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description | This patent application is a continuation of U.S. patent application Ser. No. 17/152,666, filed Jan. 19, 2021 and U.S. patent application Ser. No. 16/688,972, filed Nov. 19, 2019, issued as U.S. Pat. No. 10,966,501 on Apr. 6, 2021, which is a continuation of U.S. patent application Ser. No. 16/267,302, filed Feb. 4, 2019, issued as U.S. Pat. No. 10,477,935 on Nov. 19, 2019, which is a continuation of U.S. patent application Ser. No. 15/659,545, filed Jul. 25, 2017, which is a continuation of U.S. patent application Ser. No. 14/848,256, filed Sep. 8, 2015, issued as U.S. Pat. No. 9,713,371 on Jul. 25, 2017, which claims the benefit of U.S. patent application 62/046,453, filed Sep. 5, 2014. U.S. patent application Ser. No. 17/152,666 is a continuation of U.S. patent application Ser. No. 16/518,944, filed Jul. 22, 2019, issued as U.S. Pat. No. 10,893,737 on Jan. 19, 2021, which is a continuation of U.S. patent application Ser. No. 15/659,545, filed Jul. 25, 2017, issued as U.S. Pat. No. 10,357,094 on Jul. 23, 2019, which is a continuation of U.S. patent application Ser. No. 14/848,256, filed Sep. 8, 2015, issued as U.S. Pat. No. 9,713,371 on Jul. 25, 2017, which claims the benefit of U.S. patent application 62/046,453, filed Sep. 5, 2014. These applications and U.S. patent application 62/002,763, filed May 23, 2014, are incorporated by reference along with all other references cited in this application. The present invention relates generally to providing a portable ultraviolet (UV) light source for curing UV-curable gel nail polish. More particularly, the present invention relates to a portable UV nail lamp with a light emitting diode light source and rechargeable battery. The present invention also relates to a UV nail lamp with a light emitting diode (LED) light source and a platform for a user's hand. UV nail lamps are available for the salon and home to cure UV-curable nail polish. These nail lamps typically have UV fluorescent tubes or bulbs that use alternating current (AC) power. So, these nail lamps have an AC cord that needs to be plugged into the wall, which restricts their placement, since they need to be close to a wall socket. This can be problematic. In a salon, for example, this can restrict the number of lamps in use, the location of nail lamp stations, and thus, the number of customers that can use the lamps at a given time. The tubes or bulbs of these nail lamps consume rather significant amounts of power and generate heat, which makes these nail lamps typically large and bulky to accommodate the bulb size and to allow for heat dissipation. This makes these nail lamps somewhat difficult to move, and certainly very difficult to travel with and use in a location without a wall socket, such as while on an airplane. Further, the light from the bulbs of these lamps tends be uneven, so a person's nails are exposed to difference intensities of light output, which causes the nails to dry at different times or to cure unevenly. Further, traditional nail lamps use light bulbs that tend to produce uneven light, so a person's nails are exposed to difference intensities of light output, which causes the nails to dry at different times or to cure unevenly. These bulbs also tend to be bulky which causes the nail lamps to be large and cumbersome. Conventional bulbs can also consume much electrical energy while operating. These lamps often have a flat platform on an inside of the lamp for a user to place their hand during drying. With long drying times, the user's hand can become uncomfortable or cramp up with the fingers in a strained, stretched out position within the lamp. There is a risk that the nails can smudge before setting as the user's nails brush up against other fingers or inside the lamp. As can be appreciated, an improved nail lamp is needed. What is also needed is a method and an apparatus which can accommodate a user's five fingers in a comfortable and ergonomic resting position within a nail lamp. What is also desired is an efficient way to evenly cure UV-curable nail polish on each of the user's nails. A nail lamp for curing UV-curable nail gel uses light emitting diodes (LEDs) that emit ultraviolet light and are relatively lower power. The nail lamp is powered from an exterior power source, such as a wall socket, or by a rechargeable battery pack. A battery compartment of the nail lamp holds the battery pack, which is removable without disassembling the nail lamp. The nail lamp is easily transportable to different locations and can be used even when a wall socket is unavailable. A curing time of the nail lamp is user-selectable. The nail lamp can also include detection sensors to detect a person's hand or foot in a treatment chamber and automatically turn on or off the LEDs. A nail lamp for curing UV-curable nail gel is powered by direct current (DC) and can be battery operated. The nail lamp uses surface-mounted light emitting diodes (SMD LEDs) which are relatively lower power. The nail lamp is easily transportable and can be used even when a wall socket is unavailable, such as while traveling on an airplane or in a car. The nail lamp has a cavity or treatment chamber that can accept a user's five fingers. So, the nail lamp can evenly cure nail polish on up to five fingers at once. A compact portable LED nail curing lamp has surface-mounted light emitting diode (SMD LED) lights. The lamp provides fast and consistent results producing high gloss finish and even curing of nail polish (e.g., UV-curable gel polish). The nail lamp has a micro-USB port, which can be used to power the lamp using a wall adapter, car charger, laptop USB port, or mobile power bank for ultimate portability. In an implementation, a system includes a compact LED nail curing lamp and a mobile power battery pack. The system also includes a cable to connect the nail lamp and the mobile power battery pack. The battery pack provides portable power to the nail lamp so that the nail lamp can be used portably, such as during travel or on an airplane when a wall outlet is unavailable. A compact LED nail curing lamp has a sleek design with advanced technology, highly efficient surface-mounted light emitting diode (SMD LED) lights. The lamp provides excellent results producing high gloss finish and even curing of nail polish (e.g., UV-curable gel polish). A specific implementation of a compact LED nail curing lamp is the SMD LED Lamp S2 product by LeChat Nail Care Products of Hercules, Calif. The compact LED nail curing lamp has a micro USB port, which is convenient to use. The user can power this SMD LED lamp (e.g., LeChat's LED Lamp S2 product) using a wall adapter (included), car charger (optional), laptop USB port, or mobile power bank for ultimate portability. In an implementation, a mobile power bank battery that can be used with the SMD LED Lamp S2 product is the LeChat Mobile Power™ battery pack by LeChat Nail Care Products. This product is approved by the Underwriters Laboratories. The packaging of the product can include the certification “UL Approved.” The product is also compliant with U.S. and international standards of the Restriction of Hazardous Substances Directive (RoHS) for environmental friendly products. In an implementation, a system includes a compact LED nail curing lamp (e.g., LeChat S2 product) and a mobile power battery pack (e.g., LeChat Mobile Power product). The system also includes a cable to connect the nail lamp and the mobile power battery pack. In an implementation, the nail lamp has a micro-B USB connector input and the mobile power battery pack has a type A USB receptacle, and the cable connects these together. The battery pack provides portable power to the nail lamp so that the nail lamp can be used portably, such as during travel or on an airplane when a wall outlet is unavailable. The lamp has a large, illuminated single-button that turns the lamp on for a preset cure time of 30 seconds for efficient, rapid LED/UV gel curing. The compact design saves space and allows for portability that is convenient for travel and pedicure applications. The lamp is lightweight and designed for carrying from place to place. The nail lamp includes professional durable materials that are long lasting and reliable. In an implementation, the nail lamp is a 6-watt LED lamp that includes forty-two SMD LED lights that provide evenly distributed light that allows for an efficient cure in about 30 seconds. In an implementation, a system includes: an upper housing having a button and a power input; and a lower housing, connected to the upper housing, the cavity or treatment chamber including openings through which surface-mounted light emitting diodes can emit light through. The cavity is sufficiently wide (e.g., about 4.25 inches or 10.6 centimeters) to accommodate five fingers of a human hand placed on a flat surface. In an enclosure formed between the upper and lower, there is circuitry. The circuitry includes at least one printed circuit board with the surface-mounted light emitting diodes; a button; a multiplexer, connected to the power input; a control circuit, connected to button and the multiplexer; a timer, connected to the control circuit and the multiplexer; a recharging circuit, connected and the multiplexer. The system includes a rechargeable battery comprising a battery output coupled to the multiplexer. The recharging circuit is connected to the rechargeable battery, so it can be recharged from, for example a wall outlet, that is connected to the power input. The multiplexer switches between the power input and the rechargeable battery to supply power circuitry. The housing can include a USB power output, which can be used to power or charge other devices. The power input can be a micro USB power input, which is readily available. A nail lamp includes a housing including a base and an outer cover. On a front side of the housing, there is an opening to a cavity within the housing. Inside the housing are inner surfaces of the housing including a platform, an inner side wall, and an inner roof of the housing. The opening is shaped and sized to allow a user's hand or foot to pass through the opening into the space within the housing. A finger plate is positioned on an inside of a housing of a nail lamp. The finger plate includes five side by side depressions that are adapted to support a user's fingers when the user places a hand inside the housing on the plate. In an implementation, the finger plate is removable from the housing. Different finger plates (or foot plates) can be used for users with different size hands or feet. An arrangement of light sources is positioned on sidewalls and inner roof of an inside of a housing. The light sources can be LEDs using surface mount technology (SMT), or surface mount devices (SMD) LEDs. In an implementation, a SMD LED can produce UV light in a range of about 340 nanometers to about 410 nanometers. Other objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description and the accompanying drawings, in which like reference designations represent like features throughout the figures. FIGS. 1-8 show views of a nail lamp 100. FIG. 1 shows a perspective view, FIG. 2 shows a top view, FIG. 3 shows a front side view, FIG. 4 shows an upside down view, FIG. 5 shows a right side view, FIG. 6 shows a back side view, FIG. 7 shows a bottom or underside view, and FIG. 8 shows the nail lamp as part of a kit 800. The nail lamp device has an exterior surface 102 and at one side, an opening 104 through which a user can place their hand into an interior space 106 of the nail lamp. There is a control button on the exterior that is used to turn on an interior lighting source 108 of the device, which exposes the interior space to light from the interior lighting source. As an example, a user can insert their fingers into the interior space, turn on the cure interior lighting source, and cure their UV-curable nail polish or UV-curable nail gel coated nails with the interior light. In an implementation, there is also an exterior lighting source (e.g., an LED) of the device, which also turns on in response to the control button and is on when the interior lighting source is on. Light from the exterior lighting source is visible through a translucent material (e.g., translucent plastic) of the control button. When the interior lighting source is off, the light from the exterior lighting source will also be off. The exterior lighting source is used as an indicator that the device is on—that the interior lighting source is on. In an implementation, the interior lighting source emits light of a different wavelength from the exterior lighting source. The interior lighting source can emit UV light (wavelengths ranging approximately from 100 nanometers to 400 nanometers) to cure UV-curable gel polish. And the exterior lighting source emits wavelengths of light within the visible light spectrum (wavelengths ranging approximately from 390 nanometers to 700 nanometers). In specific implementations, the exterior lighting source emits red, green, blue, or any combination of red, green, or blue colors. The red colors include wavelengths ranging approximately from 620-740 nanometers. The green colors include wavelengths ranging approximately from 495-570 nanometers. The blue colors include wavelengths ranging approximately from 450-495 nanometers. More specifically, the nail lamp includes a housing. The housing includes an outer cover (also be referred to as an exterior surface) and inner walls. In an implementation the outer cover is made a plastic material that has a glossy sheen finish (e.g., metallic finish). On a side of the housing, there is an opening to a space (or cavity or interior space or treatment chamber) within the housing. The space within the housing is defined by inner walls of the housing. The inner walls can be made of a reflective material. This material can direct emitted light from SMD LEDs into the cavity toward the user's nails. In an implementation, the interior of the lamp includes six inner walls. One of the walls forms a ceiling of the cavity. The other walls are angled with respect to this wall. In another implementation, shown in FIG. 4, the interior of the lamp includes seven inner walls, 110, 112, 114, 116, 118, 120, and 122. In an implementation, the opening is shaped and sized to allow a user's hand to pass through the opening into the cavity. In another implementation, the opening is adapted to allow a foot to pass through the opening. In another implementation, the nail lamp is adapted to be used for both a hand and foot. FIG. 6 shows a specific implementation of a nail lamp that includes a port 124 for a micro-USB connector cable. A power source can be coupled to the port to provide the nail lamp with operating power. In other implementations, the port can be a USB port, or plug, or other types of ports for electrical power transfer. As shown in FIG. 7, on a bottom of the housing, there are grip members 126 that prevent the housing from sliding on a work surface. The grip member is one or more rubber pads which provide friction against the surface. The grip members can help stabilize the nail lamp during curing to prevent nudging the nails during use or on uneven or unlevel surfaces (e.g., table on a train or airplane). FIG. 8 shows a specific implementation of a nail lamp that is part of kit 800. The kit includes a packaging (e.g., a box) that includes the nail lamp 100, a power adaptor 128, and a USB/micro-USB cable 130. Below is a table of operational modes of the SMD LED lamp. TABLE AModeOperational Mode1. No power to power inputUV light is not operational2. Power to power inputPower UV light components and operational3. Press button when UV UV light turns on and turns off automatically light offafter 30 seconds (or other preset time)4. Press button while UV UV light immediately turns off light on FIG. 9 shows a block diagram of a cross-section of a nail lamp 900. There are five inner walls of the cavity that are visible. There is a first wall 902 that forms a ceiling of the cavity. There are two walls 904 and 906 next to the right and left of the first wall that are angled with respect to the first wall. The first, second, and third walls have SMD LEDs 907 that are attached to printed circuit boards arranged between these inner walls and the outer cover. The cavity also includes a fourth wall 908 adjacent the second wall and a fifth wall 910 adjacent the third wall. These walls have a reflective material 912 (e.g., iron, steel, aluminum, aluminum alloy, other metal or metal alloy, or other sheet metal) to direct 913 light into the cavity, and do not include SMD LEDs. A button 914 is coupled to an exterior 916 of the nail lamp. FIG. 10 shows a block diagram of a specific implementation of a first printed circuit board 1000 (PCB1). A power input 1002 (e.g., a universal serial bus (or USB) power connector input) provides power to a timer 1004, a control circuit 1006, and an LED driver 1008 of PCB1. A button 1010 is connected to the control circuit that is connected to the timer. The button can activate the control circuit that controls the timer which activates the LED driver to activate one or more SMD LEDs 1012 of PCB1. The LED driver can also control an LED 1014 that connects to the button. For example, the LED will turn on behind the button to cause the button to light up. FIG. 11 shows a block diagram of a cross section of a double-sided printed circuit board PCB1 1100 with SMD LED lights 1102 and 1104 attached to opposite sides of PCB1. There are two SMD LEDs 1102 on one side of PCB1 that emit light in a first direction away from PCB1 toward a button 1106 of the nail lamp (e.g., a back-lit control button). On an opposite side of PCB1, there is a group of SMD LEDs 1104 that emit light in a second direction away from PCB1 into a cavity of the lamp housing. FIGS. 12A-12B shows a comparison between a standard LED 1202 and a SMD LED 1204. Light from a standard LED is emitted at a smaller beam angle (angle A) compared to the SMD LED which has a greater beam angle (angle B) and beam spread. At a given distance away from a surface, the SMD LED and standard LED will each emit light in the shape of a cone. The SMD LED has a greater beam spread and will emit a greater area of illumination than the standard LED. So, a base of the cone of light (e.g., circle) for the SMD LED will have a greater area (e.g., greater diameter, B is greater than A) than that of a standard LED. Thus, fewer SMD LEDs are needed to light an area, allowing for less power used and greater energy savings. FIG. 13 shows a block diagram of a specific implementation of a nail lamp 1300 with four internal printed circuit boards. PCB1 1302 is connected to a second printed circuit board PCB2 1304 and a third printed circuit board PCB3 1306. PCB2 and PCB3 each includes at least one SMD LED light. PCB1 is also connected to a fourth printed circuit board PCB4 1308, which includes a USB connector input 1310. PCBs 1-3 provide the SMD LEDs that light the UV light cavity of the nail lamp housing. The cavity has a top horizontal section (light provided by PCB1) and two angled sections (light provided by PCBs 2 and 3) relative to the top horizontal section. And a micro USB connector (provided by PCB4) is positioned at a back of the nail lamp housing. In a specific implementation, PCBs 1-3 provide 42 LEDs, of which 24 are on PCB1,9 are on PCB2, and 9 are on PCB3. In a specific implementation, a compact LED nail curing lamp has a sleek design with advanced technology, highly efficient surface-mounted light emitting diode (SMD LED) lights. The lamp provides excellent results producing high gloss finish and even curing of nail polish (e.g., UV-curable gel polish). A specific implementation of a compact LED nail curing lamp is the SMD LED Lamp S2 product by LeChat Nail Care Products of Hercules, Calif. The compact LED nail curing lamp has a micro USB port, which is convenient to use. The user can power this SMD LED lamp (e.g., LeChat's LED Lamp S2 product) using a wall adapter (included), car charger (optional), laptop USB port, or mobile power bank for ultimate portability. In an implementation, a mobile power bank battery that can be used with the SMD LED Lamp S2 product is the LeChat Mobile Power™ battery pack by LeChat Nail Care Products. This product is approved by the Underwriters Laboratories. The packaging of the product can include the certification “UL Approved.” The product is also compliant with U.S. and international standards of the Restriction of Hazardous Substances Directive (RoHS) for environmental friendly products. In a specific implementation, the lamp has a large, illuminated single-button that turns the lamp on for a preset cure time of 30 seconds for efficient, rapid LED/UV gel curing. The compact design saves space and allows for portability that is convenient for travel and pedicure applications. The lamp is lightweight and designed for carrying from place to place. The nail lamp includes professional durable materials that are long lasting and reliable. In a specific implementation, the nail lamp is a 6-Watt LED lamp that includes forty-two SMD LED lights that provide evenly distributed light that allows for an efficient cure in about 30 seconds. An SMD LED is mounted and soldered into a circuit board. Compared to a standard LED, an SMD LED is small in size since it has no leads or surrounding packaging that a standard LED has. A SMD LED does not have the standard LED epoxy enclosure, and thus, SMD LED lights emit a much wider viewing angle instead of the focused, narrow light of the standard LED. SMD LEDs provide advantages over standard LEDs. The SMD LED has lower voltage and current requirements which allows it to give off very little heat. SMD LEDs emit a higher level of brightness while consuming less power than standard LEDs. With standard LEDs, the UV light produced to cure UV gels over time breaks down the epoxy surrounding the standard LED causing the epoxy to crack. Once cracked, the standard LED no longer flows evenly, which disrupts the transmission of light, resulting in an uneven cure. In contrast, SMD LEDs have no epoxy that surrounds it, and thus, will not crack. The resulting emission of light will be even throughout the lifetime of the light. Further, standard LEDs use a higher voltage and therefore, produce more heat. The heat produced by the higher voltage LED lights can shorten the life of the standard LED, which causes them to go out faster compared to SMD LEDs. In a specific implementation, the SMD LED Lamp S2 product is a nail lamp having a 6-Watt LED lamp with an output voltage of 5 volts and 1.2 amps. The lamp includes 42 SMD LED lights. A width of the lamp is about 103.5 millimeters. A length of the lamp is about 146.5 millimeters. A height of the lamp is about 56 millimeters. In an implementation, the nail lamp product is part of a kit which includes a universal AC adapter. The adapter has an input power of about 100 volts to about 200 volts at 50 or 60 hertz. The adaptor has an output power of about 12 volts at 1.2 amps. The kit also includes a user guide or manual which includes operating instructions, safety warranty, product specifications, a certificate of warranty, and a warranty registration card. To use the SMD LED Lamp S2 product, a user can follow the following instructions (which are included on the user manual): 1. Plug the power adaptor into the back of the SMD LED lamp and then plug the other end into a wall outlet, a car outlet, a computer, or a mobile power bank. 2. To turn the SMD LED lamp “on,” press the power button that is located on top of the lamp to the “on” position, where the LED light of the button lights up. The lamp will automatically shut off after 30 seconds. 3. The SMD LED lamp can be used with both fingernails and toenails. For toenails, the user can place the lamp over toes and perform steps 1 and 2 above. The user should follow the following safety precautions when using the SMD LED lamp product. These precautions are included on the user guide as part of the kit. 1. Never look directly into the LED/UV lights when machine is ON. 2. Do not overexpose the nails or skin under light. 3. Do not use the LED light in or around water. 4. Unplug the LED light when not being used. 5. Certain cosmetics or prescriptive lotions can cause sensitivity to LED light. Do not use lamp if using any. 6. Do not pull the cord to unplug. Instead, grab plug firmly and pull to unplug. 7. Do not use any corrosive sanitizer, solvents, thinners, or scrubbing to clean the machine. 8. Do not stack anything on top of the LED Lamp. 9. Do not disassemble the LED Lamp. This will void the Warranty. 10. Do not try to repair the machine. Please contact the distributor for service. 11. The plastic bag in packaging is a choking hazard. Do not place over head. Keep away from children and pets. 12. The electric power system is labeled on the box. Please pay attention to the voltage and frequency. FIG. 14 shows a block diagram of a specific implementation of a nail lamp that is adapted to be used with a rechargeable battery pack 1402 that is external 1404 to the housing 1406 of the nail lamp. The rechargeable battery is a unit that is separate from the nail lamp. Circuitry to recharge this rechargeable battery pack is contained within (or internal 1408 to) a housing of the rechargeable battery pack. There battery pack (or the nail lamp) may have a battery gauge or charge level indicator that indicates a charge level remaining in the battery. For example, the battery gauge can indicate there 75 percent charge remaining in the battery pack. For example, in an implementation, the display of the nail lamp can display the battery charge level of the battery pack (such as by the user pressing a battery charge level button). For example, the rechargeable battery is a portable power pack with a USB plug output (e.g., type A USB receptacle). The nail lamp has a USB power connector 1410 (e.g., micro-B USB receptacle) that can connect to the rechargeable battery using a cable. The micro-B USB receptacle of the nail lamp is connected to the type A USB receptacle of the rechargeable battery via a micro USB cable. Then, the battery pack supplies power to the nail lamp (which consumes 6 watts maximum). In an implementation, the nail lamp consumes 6 watts or less of power. Through the USB, the power adapter or batter can provide about 5 volts and 1.2 amps. In other implementations, the nail lamp consumes 5 watts or less of power (e.g., 5 volts and 1 amp), 4.5 watts or less (e.g., 5 volts and 900 milliamps), or 2.5 watts or less of power (500 milliamps). In another implementation, the nail lamp consumer more than 6 watts, such as 10 watts (e.g., 5.1 volts and 2.1 amps) or 12 watts (5.1 volts and 2.4 amps). With more power, the cavity of the nail lamp can be made larger (allow for more comfort or larger hands), or there can be more LEDs (for more even light coverage), or higher intensity LEDs (possibly for better nail curing), or any combination of these. Thus the nail lamp and rechargeable battery are a nail lamp system that allow for cordless (e.g., not connected to a wall outlet) and portable use. Users and customers need not rely on being within proximal distance to a wall outlet. In a salon, this can restrict the number of lamps in use, the location of nail lamp stations, and thus, the number of customers that can use the lamps at a given time. With a portable rechargeable nail lamp, salon customers can dry their nails anywhere in the salon, which allows for more customers that can be serviced at a given time, and reduced wait times for customers. Further, a portable rechargeable nail lamp is convenient to use during travel (e.g., on a train or airplane), and in places where there is limited or no access to wall outlets. Users can also save time by drying their nails while doing other tasks that would otherwise had to have been done at other times. For example, while working on a laptop or making phone calls at work, a person can concurrently cure their nails while the nail lamp is running on batteries or connected to their laptop. Although this application specifically describes the nail lamp as having a micro-B USB receptacle and the battery pack as having a type A USB receptacle, one having ordinary skill in the art understands that other connector types can be used to provide power. For example, some other connectors may be used such as mini-USB connector (e.g., USB mini-B), mini-A, micro-AB, or Apple's lightning connector. In a specific implementation, a portable external battery pack is the LeChat Mobile Power™. The Mobile Power pack product includes a battery housing having a USB output port, a micro USB input port, an LED power indicator, a power or flashlight button, and an LED light. The Mobile Pack product also includes a cable for connecting the battery housing with a nail lamp (e.g., the SMD LED Lamp S2 product). The cable includes a USB cable, a micro USB connector on one end of the cable, and a USB connector on an opposite end of the cable. To charge the Mobile Power product, a user can connect the micro USB connector of the cable to the micro USB input port of the external battery housing, and the other USB connector end of the cable to a USB port of a power source including a wall adapter (to a wall outlet), a laptop USB port, a desktop USB port, or a DC 5-volt USB charger. The LED power indicator of the battery pack will flicker to indicate that the external battery has started charging. When all LED power indicator lights are lit, this indicates that the battery is fully charged. In an implementation, there are four battery indicator lights arranged in a row on an external surface of the battery pack. When the Mobile Power battery pack is fully charged and ready to be used to power an electronic device, the user should first check whether the charging voltage of the digital or electronic device is matched with an output voltage (DC 5 volts) of the external battery. The user can connect the USB connector of the cable to the USB port of the battery pack, and the other micro USB connector end of the cable to a micro USB port of an electronic device such as the SMD LED nail lamp. The can be used as a general mobile power pack, and can be used to power other electronic devices such as a smart phone, tablet device, or any electronic device with a DC 5-volt USB input. A number of the battery LED power indicator lights will light according to the remaining charge capacity of the battery pack. In a specific implementation, there are four indicator lights (L1-L4) in a row with L1 on a left end, L2 to the right of L1, L3 to the right of L2, and L4 to the right of L3, and on the right end. When L1 is flashing, this indicates that there is about 0 to about 25 percent charge capacity level in the battery. When L1 and L2 are flashing, this indicates that there is about 25 to about 50 percent charge capacity level in the battery. When L1, L2, and L3 are flashing, this indicates that there is about 50 to about 75 percent charge capacity level in the battery. And when L1, L2, L3, and L4 are flashing, this indicates that there is about 75 to about 100 percent charge capacity level in the battery. When the capacity remaining in the battery is less than about 5 percent, the first light (L1) will blink to remind the user to recharge the external battery. In a specific implementation, the external battery includes a flashlight button for a flashlight function. To activate the flashlight option, the user can double click the flashlight (or power) button on the battery. Brightness of the light will cycle between 10 percent, 50 percent, and 100 percent brightness. The flashlight should not be turned on under hot temperature environments for long periods of time. In a specific implementation, when the power button is pressed, the LED indicator lights will turn on. These lights will automatically turn off in about 10 seconds for power saving. When needing to charge or power digital or electronic products, the user can simply plug the cable into the external battery device, and it will start charging when it detects the load. The user should follow the following safety precautions when using the Mobile Power product. These instructions are included in a kit containing the Mobile Power product. 1. Charge fully before using the mobile power device. 2. Do not place or use mobile device at high temperature or in humid environment. Do not expose to excessive sunlight. (Operating temperature range: charging: 0 degrees Celsius to 45 degrees Celsius; discharging: −10 degrees Celsius to about 60 degrees Celsius; and storage environment: about −20 degrees Celsius to about 60 degrees Celsius). 3. The user should not throw the mobile power device in fire or water so as to avoid fire, explosion, or both. 4. Keep the mobile power device out of reach of children. 5. Do not disassemble the device arbitrarily, since in some of the products, there are no removable or maintainable parts that are installed in the product. 6. Do not vigorously shake, hit or impact the mobile power device. 7. If the mobile power device has exposed liquid or other abnormalities, discontinue use, and contact customer service. 8. If the mobile power device has liquid leakage and splashes into the user's eyes, do not rub the eyes, wash with clean water immediately, and go to the hospital for medical treatment. 9. It is normal for the temperature of the mobile power device to rise during use; do not operate in a confined environment. 10. The transmission lines and connectors of the mobile power device must be provided by the original manufacturer. The use of transmission lines or connectors of nonoriginal manufacturer may result in severe or fatal injuries and property losses. 11. Do not cover or block the mobile power device with paper or other objects, to avoid blocking the heat dissipation and cold cutting. 12. Do not use the mobile power device if nobody is watching it in the car or anywhere. 13. Before using mobile power device, check its voltage demand. 14. If the mobile power device is not used for a long period of time, please charge or discharge it once every three months to ensure service life. 15. Remove power supply and power cord when the mobile power device is not in use. 16. Fully charge the mobile power device after the mobile power device is fully discharged. FIG. 15 shows a block diagram of a specific implementation of a nail lamp 1500 having a PCB5 1502 that can receive power from a USB power connector 1504 (e.g., micro-B USB receptacle) or rechargeable battery pack 1506. Unlike the FIG. 14 system, the rechargeable battery pack is specifically adapted to connect directly to the nail lamp circuitry (powering the nail lamp) without using the USB power connector. Specifically, power is not provided from the battery pack through the USB power connector, but rather directly from the battery. Further, the rechargeable battery pack can integrate with the housing of the nail lamp. In an example, the rechargeable battery pack snaps into place into a bottom of the nail lamp via a latching mechanism. And the rechargeable battery pack can be unlatched to be removed and replaced with a new pack, which may be desirable when the pack is spent or no longer holding charge (e.g., at the end of life of the pack). In an implementation, compared to the FIG. 14 system, circuitry to recharge this rechargeable battery pack is contained within a housing of the nail lamp (e.g., PCB5 of the nail lamp). Referring to FIG. 16, PCB5 is similar to PCB1 as described previously, but includes a recharging circuit 1602 and other circuitry to multiplex 1604 (mux), switch, or other switching mechanism to switch between taking power from the USB power connector or the rechargeable battery pack. Power from the USB power connector (such as connected to a wall adapter or other power source) can be used to power the nail lamp and also recharge (via the recharging circuit) the rechargeable battery too. FIG. 17 shows an implementation where the nail lamp of FIG. 16 includes one or more USB power output connectors 1701. These connectors can be used to charge a user's or customer's device, such as a phone or tablet. The user or customer will connect their device (e.g., phone) via a cable to one power output connectors. The device will be charged from the power from the USB power connector input 1702 or the battery 1703 through a mux 1704 or switch. Typically when the USB power input is connected to power, this power is used to charge the user's device (and also the rechargeable battery pack of the nail lamp). When the USB power input is not connected to power, the user's device is charged by the nail lamp battery. FIG. 18 shows an example of a rechargeable battery pack 1802 that can be connected 1803 to the housing of nail lamp 1804. In this implementation, the battery is contained within a base plate 1806 of the nail lamp. When the nail lamp is used, the user or customer places their fingers (that will be exposed to the UV light) onto the battery pack base plate. The battery pack base plate snaps or latches into place in the housing of the nail lamp. FIG. 19 shows an outline of a plan view of the battery pack base plate. More specifically, referring to FIG. 18, the rechargeable battery pack connects to the nail lamp at one or more connection points via connectors. For example, the nail lamp has a connector for connecting to the external rechargeable battery pack which the nail lamp is designed for. In a specific implementation, the nail lamp has a female connector while the external rechargeable battery pack has a corresponding male connector that fits into the nail lamp's connector. In another specific implementation, the nail lamp includes a male connector that fits into the external rechargeable battery pack's female connector. In other implementations, however, the nail lamp's connector can have any number or combination of pins and shapes in order to interface with the external rechargeable battery pack that the nail lamp is designed for. In a specific implementation, the nail lamp can include a fastening member that fastens to the external rechargeable battery pack to ensure a tight fit. As an example, the nail lamp can include a latch to secure the lamp to the battery. In another specific implementation, when the external rechargeable battery pack is connected to the nail lamp, the nail lamp looks for an authentication or handshaking signal (e.g., sending of an authentication code). If the lamp does not receive the proper authentication, the lamp may display a signal (e.g., flashing lights) that the battery is not an authorized peripheral for the lamp or the lamp can simply not allow the lamp circuitry to interface with the battery (e.g., not allow charging). An authentication circuit can be included in the circuitry of the lamp to provide proper authentication to the nail lamp. FIG. 19 shows a specific implementation an outline of a plan view of the battery pack base plate 1806 that is designed for a nail lamp. In an implementation, the nail lamp is the SMD LED Lamp S2 product by LeChat Nail Care Products. The shape of the external rechargeable battery pack corresponds to the shape of a base of the nail lamp, which connects to the external rechargeable battery pack. The shape of the external rechargeable battery pack allows a user to align the battery with the shape of the nail lamp base for connecting the two portions together. When connected, where the lamp and battery portions meet, the exterior surfaces become flush with each other. There will be a seam that is between the nail lamp and the battery pack. At the seam, the surfaces of the lamp and battery are relatively flush with each other. The seam line remains visible and can be felt tactilely. The battery pack base plate can have a finger plate integrated with the plate. In an implementation, the finger plate is removable from the base plate to allow for replacement or cleaning between uses. More discussion on a finger plate is in U.S. patent application 62/002,763, which is incorporated by reference. FIG. 20 shows a block diagram of a specific implementation of a kit 2000 for a nail lamp. The kit includes a UV light unit 2002, a battery pack 2004, a USB charger 2006, a USB charging cable 2008, and a user guide 2010 or instructions on use. These components can be arranged in a packaging of the kit which can include a box. In an implementation, the box can have compartments or trays for holding the components in place within the box. For example, one kit implementation is the system described in connection with FIG. 14 above. This kit has the battery pack connecting to the lamp with the USB connector input, and also the recharging circuitry is contained within the battery pack housing. Another kit implementation is the system described in connection with FIGS. 15-19 above. This kit has the battery pack directly connecting to the lamp, rather than through the USB connector input. The recharging circuitry is contained within the nail lamp housing. FIG. 21-23 show views of another implementation of a nail lamp 2100. FIG. 21 shows a perspective view, FIG. 22 shows a top view, and FIG. 23 shows a right side view. The nail lamp device has an exterior surface and at one side, an opening through which a user can place their hand into an interior space of the nail lamp. There are controls on the exterior that are used to turn on an interior lighting source of the device, which exposes the interior space to light from the interior lighting source. As an example, a user can insert their fingers into the interior space, turn on the cure interior lighting source, and cure their UV nail polish or UV nail gel coated nails with the interior light. In an implementation, the device includes sensors that detect when a hand is present inside the unit. This turns on both the interior curing lights as well as the exterior glowing lights for an allotted time (e.g., turning off after 15, 30, or 60 seconds). The light can also be manually turned on or off with, for example, button controls as an additional convenience. In an implementation, there is also an exterior lighting source of the device, which also turns on in response to the controls and is on when the interior lighting source is on. Light from the exterior lighting source is visible through a translucent shell (e.g., translucent plastic) of the exterior of the device. The translucent shell can be clear material or a light-diffusing material. When the interior lighting source is off, the light from the exterior lighting source will also be off. The exterior lighting source is used as an indicator that the device is on—that the interior lighting source is on. The entire exterior surface of the device can be lighted when on. This exterior lighting feature will make it easier for the user to know that the light is on and the curing cycle is continuing. The user will be able to see the exterior light is on from many positions and many angles, especially compared to attempting to peek into the opening (which will be partially blocked by a hand) and trying to see whether the interior lighting source is on. And the interior lighting source may not be visible light. In an implementation, on the exterior, there is a digital display. The display shows a length time in digits that the light will be turned on for. Further, the display can be a count down (or count up) timer that shows the time remaining for the light to be on. The digital display is optional and can be omitted in some implementations. More specifically, the nail lamp includes a housing 2102. The housing includes a base 2103 and an outer cover 2105. On a front side of the housing, there is an opening 2107 to a space (or cavity) within the housing. The space within the housing is defined by inner surfaces of the housing including a platform 2109, an inner side wall 2111, and an inner roof (not visible). The inner surfaces of the inside of the housing can be made of metal, plastic, or a combination of these. In an implementation, the opening is shaped and sized to allow a user's hand to pass through the opening into the space within the housing. The user's hand can be positioned within a cavity formed by the space, surrounded by the inner surfaces of the housing. In another implementation, the opening is adapted to allow a foot to pass through the opening. In another implementation, the nail lamp is adapted to be used for both a hand and foot. The outer cover of the housing includes a screen or display 2120 and controls, which in an implementation, are button features 2122a, 2122b, and 2122c. The screen may be an LED-backlit liquid crystal display (LCD) to display to a user a status or parameter of the nail lamp such as a time elapsed or a time remaining for a particular cure setting of the lamp. The display can also indicate other parameters of the lamp such as a power setting (e.g., “ON,” “OFF,” “LOW,” “HIGH,” or other messages). The screen can display images such as words, digits, 7-segment displays, meters, and others. The button features can indicate various cure settings of the nail lamp. Each button can be associated with a certain time of curing. For example, a first button can indicate a first timer setting for a first interval of time (e.g., 15 seconds). When a user selects the first timer setting by pushing the first button, an LED light source of the lamp will turn on for a time of 15 seconds of curing. A second button can indicate a second timer setting for a second interval of time (e.g., 30 seconds), and a third button can indicate a third timer setting for a third interval of time (e.g., 60 seconds). In other implementations, there can be fewer buttons (e.g., 1 or 2 buttons) or more than 3 buttons (e.g., 4, 5, or 6, or greater). FIG. 24 shows a view of an inside of a housing of a nail lamp, as viewed from a lower surface of the interior space looking toward the upper surface (e.g., inner roof). Side surfaces or side surfaces are angled with respect to the lower surface. The upper surface and side surfaces include a number of light source structures as shown. In an implementation, the light source structures are surface mounted light emitting diodes (LEDs). The LEDs can be referred to a surface mounted devices or SMDs. The LEDs are surface mounted to one or more printed circuit boards that housed within the device's enclosure, between surfaces of the interior space and exterior shell of the device. In other implementation, light sources can include other types of LEDs (other than SMDs), laser diodes, light bulbs, or other lighting. Some light source structures can be different from other light source structures. For example, first light structures 2421, 2423, 2425, 2427, 2429, 2431, 2433, 2435, 2437, 2439, 2441, 2443, 2445, and 2447 are different from the other light structures, which can be referred to as second light structures. In an implementation, the first light structures have higher energy output than the first light structures. For example, the first light structures can be 2-watt LEDs, while the second light structures are 1-watt LEDs. The light sources can include lights of the same or different output power and wavelength. In the specific arrangement of lights in FIG. 24, LED lights are positioned on the side walls and roof of the inside of the housing. There are seven side walls connected to the roof. The shaded LED lights (2421, 2423, 2425, 2427, 2429, 2431, 2433, 2435, 2437, 2439, 2441, 2443, 2445, and 2447) indicate 2-Watt output LEDs, while the remaining unshaded LED lights are 1-Watt output LEDs. Generally, on side walls of the housing, each 2-Watt LED is positioned between two 1-Watt LEDs. This distribution of LEDs can provide each nail of a user's hand (or foot) with an even exposure of light since a 2-Watt LED is positioned near each nail, as shown in FIG. 18. In other implementations, the LEDs can be arranged in another arrangement, such as an alternating pattern. On the inner roof of the housing, there is a combination of 2-Watt and 1-Watt LED lights. The 2-Watt LEDs can be arranged to correspond to a user's nails, so that a 2-Watt LED is near each nail. For example, when the user's left hand is inserted into a cavity of the housing, as shown in FIG. 18, each nail of the hand is irradiated by at least two nearby 2-Watt LEDs. Referring to FIG. 24, with the user's hand placed in the cavity, each nail is irradiated by at least one nearby sidewall LED and one nearby inner roof LED. Table B below shows how each nail is irradiated for both right and left hands of the user. TABLE BRight HandLeft HandSidewallSidewallFingerLEDRoof LEDFingerLEDRoof LEDThumb nail24212435Thumb nail24332447Index nail24252439Index nail24292443Middle nail24272441Middle nail24272441Ring nail24292443Ring nail24252439Little nail24312445Little nail24232437 Each nail is also irradiated by at least two 1-Watt LEDs. For example, when the left hand is placed in the cavity, the thumbnail is irradiated by 2-Watt LEDs 2421 and 2437, and by the two 1-Watt LEDs surrounding LED 2421. The index fingernail is irradiated by 2-Watt LEDs 2425 and 2439, and by two 1-Watt LEDs between LEDs 2425 and 2427, and between LEDs 2439 and 2441. FIG. 25 shows an inside view of a housing of a nail lamp in relief. Light sources are positioned along sidewalls and inner roof of the housing. The side walls and roof include openings or apertures to expose a light source, which can be positioned in or behind the opening. Light from the light source radiates through the opening and into the space provided by the housing. By using surface mounted LEDs, the LEDs are recessed in openings of the enclosure. This is in comparison to other not-surface-mounted types of LEDs that have a bulb-portion that extend through the openings. Also in some implementations, the LEDs can be flush with the enclosure surface. FIG. 26 shows specific arrangement of LED lights on sidewalls and inner roof of a housing. The LEDs that are circled are 2-Watt LEDs using surface mount technology (SMT). These LEDs are referred to as surface mount devices (SMD) LEDs. The LEDs that are not circled, that are positioned between the 2-Watt LEDs, are 1-Watt SMD LEDs. In an implementation, a SMD LED can produce UV light in a range of about 340 nanometers to about 410 nanometers. In a specific implementation, the SMD LEDs can produce UV light at about 395 nanometers peak irradiance. In another specific implementation, the SMD LEDs can produce UV light at about 350 nanometers. In another specific implementation, the SMD LEDs can produce UV light at about 365 nanometers. FIG. 27 shows a specific arrangement of LED lights on sidewalls and inner roof of a housing with five inner sidewalls of the housing. The configuration of LED lights in FIG. 27 is slightly different from that shown in FIGS. 24, 25, and 26. There are two fewer LEDs than the other configurations. The circled LEDs indicate 2-Watt SMD LEDs, and the uncircled LEDs indicate 1-Watt SMD LEDs. For each sidewall, one 2-Watt LED is positioned between two 1-Watt LEDs. FIG. 28 shows a specific arrangement of SMD LED lights on sidewalls and inner roof of a housing with seven inner sidewalls of the housing. Compared to the arrangement in FIG. 7, this housing includes 2 additional sidewalls, each with a 2-Watt LED 2806 and 2808. So, the arrangement in FIG. 7 has five 2-Watt LEDs on sidewalls, while this arrangement includes seven 2-Watt LEDs positioned on sidewalls. The arrangement with two additional LEDs can increase the cost of the device, but provides the irradiation for curing, which can reduce curing time and improve a uniformity of the curing. FIG. 29 shows a top view of a finger plate 2901. The finger plate is placed onto the lower surface of the interior space of a nail lamp. The finger plate is a guide for the fingers, so the fingers will be properly positioned inside the nail lamp. The user places the fingers on the finger plate, and the nails are held in position for exposure to the curing light. The finger plate can be removable (e.g., sliding out from a bottom of the lamp), such as for cleaning or so other finger plates can be used for different sized fingers. The finger plate is designed for the right or left hand, but in other implementations, there may be a specific finger plate design for each hand. The finger plate includes five side by side depressions or grooves that are adapted to support a user's fingers when the user places a hand inside the housing on the plate. A first depression 2902 can be a sloped surface (or indentation, groove, or recess) for supporting the user's thumb or little finger. A second depression 2903 can be a groove (or indentation or recess) for supporting the user's index or ring finger. A third depression 2904 can be a groove (or indentation or recess) for supporting the user's middle finger. A fourth depression 2905 can be a groove (or indentation or recess) for supporting the user's index or ring finger. A fifth depression 2906 can be a sloped surface (or groove, indentation, or recess) for supporting the user's thumb or little finger. The finger plate can include thumb guides 2910 and 2911 that include circular grooves in the finger plate. The circular groove can provide a tactile guide for the user to place the thumb when the user inserts the hand into the housing. The thumb guide allows the user to keep the hand in the same position through the curing so that the nails cure evenly and without smudging. In an implementation, the finger plate is removable from the housing. Different finger plates can be used for users with different size hands. The finger plate can also be removed to facilitate cleaning of the plate and of the inside of the housing. In salons, the plate can be removed between uses to sterilize the plate for a new user. The finger plate can also be replaced with a foot plate for curing polish on a person's foot for a pedicure. FIG. 30 shows an outline of the finger plate overlaid on a bottom up view of an inside of a housing of a nail lamp. This figure shows the positioning of the light structures in relation to the finger plate grooves. Light sources are arranged along an inner roof of the housing. The roof includes openings or apertures to expose a light source (e.g., LED, or SMD LED, or others), which can be positioned in or behind the opening. Light from the light source radiates through the opening and into the space provided by the housing. FIG. 30 shows a specific arrangement of light sources relative to a finger plate of the housing. The finger plate includes finger grooves, with spacers (e.g., raised regions or ridges) between adjacent finger grooves. There is at least one light source positioned over each finger groove. Over a first finger groove 3002, there are two openings with a light source at each opening. There is a light source positioned over a second finger groove 3003, third finger groove 3004, and fourth finger groove 3005. A light source is positioned between and over the second and third finger grooves, and the third and fourth finger grooves. There are two light sources positioned over a fifth finger groove 3006. FIG. 31 shows a specific implementation of a finger plate 3101 with extended grooves for fingers of a user's hand. There can be spacers 3105 between adjacent grooves. The finger plate includes stops 3107 in some grooves to prevent the user's fingers from sliding in the grooves (e.g., away from or toward the light sources). The stops can provide a tactile gauge for the user to indicate where to place the fingers during curing. In a specific implementation, a height of the stops is about 3 millimeters from a surface of the groove. In other implementations, the height is less than 3 millimeters (e.g., 0.5, 1, 1.5, 2, or 2.5 millimeters or greater). In other implementations, the height is greater than 3 millimeters (e.g., about 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4 millimeters or more). In an implementation, a finger plate can have shorter or longer grooves than that of FIG. 31. FIG. 32 shows an implementation of a finger plate with grooves that are shorter compared to the finger plate in FIG. 31. An edge 3202 of the finger plate provides a stop for a user's fingers. The edge can have raised regions or stops to provide the user with a tactile guide for placement of the fingers or fingertips. In a specific implementation, a height of the stops is about 1.5 millimeters from a surface of the groove. In other implementations, the height is less than 1.5 millimeters (e.g., 0.5, 1, 1.1, 1.2, 1.3, or 1.4 millimeters). In other implementations, the height is greater than 1.5 millimeters (e.g., about 1.6, 1.7, 1.8, 1.9, or 2 millimeters or more). In other implementations, the edge does not have a raised rim, and the user can place the fingertips at the edge itself. FIG. 33 shows the positioning of a user's hand (e.g., left hand) in the finger plate of FIG. 31, against the finger stops. FIG. 34 shows the positioning of a user's hand (e.g., left hand) in the finger plate of FIG. 32, against the finger stops. FIG. 35 shows a rear perspective view of a finger plate. A top view of the finger plate is in FIG. 29. As discussed, the plate can include five depressed regions (e.g., finger grooves) with adjacent regions separated by a raised region 3505 (or ridge). Three of the finger grooves, in the middle, are elevated compared to the other two finger grooves, on either side of the middle three. The depressed regions can be contoured or curved to provide comfort to a user's fingers when resting in the depressed regions. The depressed regions and raised regions can also prevent the fingers from moving while curing which can cause uneven curing or smudging. FIG. 36 shows a front perspective view of a finger plate. A first groove 3602 and a fifth groove 3603 are less raised from a base of the housing than second, third, and fourth grooves 3604, 3605, and 3606. The first and fifth grooves are slightly angled away from the second, third, and fourth grooves. A surface of the fingerplate between a front edge of the grooves and a base of the finger plate can be sloped. By elevating the second, third, and fourth finger grooves, the fingers will be positioned closer to the upper surface and the light structures. This will increase the radiation to the fingers which improve curing of the polish or gel. Curing time will be reduced and the uniformity of the curing will improve. Further, this structure reflects a natural positioning of a person's fingers at rest. So, when a user places fingers into the grooves of the finger plate, the fingers can rest in a natural position that ergonomic and comfortable than if the grooves were positioned at the same height from the base of the housing. FIG. 37 shows an irradiation pattern for light structures for the arrangement of FIG. 27. This specific arrangement of lights (e.g., LEDs) has sidewalls and inner roof of a housing with five inner sidewalls of the housing. A user's hand is positioned in the housing and each nail is irradiated by nearby light sources. A thumbnail is irradiated by three nearby light sources while a little finger nail 3705 is irradiated by two nearby light sources. In a specific implementation, for each sidewall of the housing, there is one 2-Watt LED that is surrounded by two 1-Watt LEDs. The thumbnail is irradiated by all three LEDs, while the little finger nail is irradiated by two 1-Watt LEDs. FIG. 38 shows an irradiation pattern for light structures for the arrangement of FIGS. 24, 25, 26, and 28. This specific arrangement of lights (e.g., LEDs) has sidewalls and inner roof of a housing with seven inner sidewalls of the housing. Compared to the arrangement in FIG. 37, there are two additional sidewalls 3803 and 3805, each sidewall with a light source 3806 and 3808. In this arrangement, the user's nails (right hand or left hand) can be evenly irradiated. The thumbnail and little finger nail of each hand can be each irradiated by at least three light sources. In a specific implementation, for each sidewall of the housing with three light sources, there is one 2-Watt LED that is surrounded by two 1-Watt LEDs. On each sidewall 3803 and 3805, there is one 2-Watt LED. The thumbnail and little finger nail is each irradiated by one 2-Watt LED and two 1-Watt LEDs. FIG. 39 shows a finger plate for an inside space having five inner sidewalls, such as used in connection with the light structure arrangement of FIG. 27. FIG. 40 shows a finger plate for an inside space having seven inner sidewalls, such as used in connection with the light structure arrangement of FIG. 28. The finger plates described in this application can be adapted or modified to be used with the configuration of FIG. 27 or 28, or both. For example, the finger plate in FIG. 40 can be used with the FIG. 27 configuration. And the finger plate in FIG. 39 can be used with the FIG. 28 configuration. Compared to the configuration in FIG. 39, two additional side walls 4006 and 4008 can be added at corners 3906 and 3908. The finger plate also includes indicator members 4010 (finger points) positioned in the grooves of the finger plate. In an implementation, the indicator members are raised dots or bumps analogous to Braille dots that provide the user a tactile guide that the fingertips are positioned properly. Note that for the first and fifth grooves, these include two indicator dots. This is because there grooves, depending on which hand, are for the thumb or pinkie, which are a different length. In other implementation, the indicator members can be other raised regions (e.g., bump, projection, or ridge, or others) or recessed regions that can provide the user tactile feedback. When the user inserts the hand into grooves of the finger plate, the user cannot see how far to extend the fingers into housing. With the indicator members, the user can feel where to position the hand during curing. FIG. 41 shows a front view of an inside of a housing of a nail lamp with an outer cover of the housing removed. The side walls and roof include openings 4105. Light source structures 4110 can be located in or behind the openings and are exposed through the openings. Light sources can be connected to circuit boards 4115. In a specific implementation, light sources are SMD LEDs that are mounted onto circuit boards. Circuit boards 4115 may be printed circuit boards upon which the surface mounted LEDs are soldered. There can also be heat sinks or heat fins to which the LEDs are attached to dissipate heat. There can be LEDs mounted on both sides of a printed circuit board. One side will include the LEDs facing the inside of the interior space, while the other side will include the LEDs for lighting the exterior of the device. There can be multiple printed circuit boards, with boards for the sidewalls and upper surface of the interior space. FIG. 42 shows a front view of an inside of a housing of a nail lamp with five inside side walls. Side walls are angled with respect to a vertical y-axis to allow the light sources to be angled toward a finger plate of the housing. In a specific implementation, an angle 4209 at which a side wall is angled with respect to the vertical axis is about 30 degrees. In other implementations, the angle is less than 30 degrees (e.g., about 20, 21, 22, 23, 24, 25, 26, 27, 28, or 29 degrees). In other implementations, the angle is greater than 30 degrees (e.g., about 31, 32, 33, 34, 35, 36, 37, 88, or 39 degrees, or more). FIG. 43 shows a front view of an inside of a housing of a nail lamp with seven inside side walls. Compared to the configuration in FIG. 42, the side walls can be less angled with respect to the vertical y-axis. In a specific implementation, an angle 4309 at which a side wall is angled with respect to the vertical axis is about 26 degrees. In other implementations, the angle is less than 26 degrees (e.g., about 18, 19, 20, 21, 22, 23, 24, or 25 degrees). In other implementations, the angle is greater than 26 degrees (e.g., about 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 88, or 39 degrees, or more). FIG. 44 shows a top view of an exterior of a nail lamp. There are preset settings for a user to select for curing. In an implementation, the user can select a preset curing time (e.g., 15 seconds, 30 seconds, or 60 seconds). The UV nail lamp in FIG. 44 is set to a setting of 60 seconds curing time. When the user presses the button for the selected setting, the button can light up and remain lit during the curing. A display can indicate to the user how much time has elapsed or is remaining on the curing time. The display shows 20 seconds (or 2 seconds) has elapsed or is remaining of the selected 60 seconds. Once the time expires, the UV lights, along with the lights of the housing, will turn off. In an implementation, when the user selects the desired cure time by pressing the button, the display will display the selected time. In an implementation, an exterior lighting source of the device does not turn on until a person's hand is inserted inside of the nail lamp. When the hand is inside, a sensor of the device detects when a hand is present inside the unit. This turns on both the interior curing lights as well as the exterior glowing lights for duration of the selected curing. When curing begins, exterior light source of the device will turn on, causing the exterior surface of the lamp to glow a soft and steady light for the duration of the curing time. The exterior lights can be positioned within the device, between interior curing lights and an outer translucent cover of the device. The translucent cover can be a translucent plastic material. The translucent plastic material can be a diffusing material or a diffuser, or the translucent plastic material can be combined with another diffusing material or diffuser, such as a composite material including both a translucent plastic layer and a light diffusing layer. In an implementation, the translucent plastic material of the lamp shell includes a light diffusing property. When light irradiated from the exterior light source hits an inside surface of and is transmitted through the translucent plastic material, the plastic material diffuses or spreads out (i.e., scatters) the light to give a softer light relative to the more concentrated light initially radiated from the exterior lighting source (e.g., diode on the circuit board). The scattered light can be across the entire exterior shell and cause the device to have a soft and steady glow of light. For example, in FIG. 44, about six exterior lights sources are used to illuminate and cause the lamp's exterior surface to glow. The light diffuser material spreads and homogenizes the nonuniform or uneven illumination of six light sources into a more uniform illumination. In an implementation, light diffusing property is present across an entire exterior surface area of the shell. When light from an exterior lighting source (located inside the nail lamp housing) enters an inside surface of the lamp shell, the light diffusing material scatters the light across the entire exterior surface area of the shell. This causes a more even glow across the entire lamp shell. In an implementation, the lamp shell has a light diffusing property when the lamp shell is made of a translucent material and a light diffuser film is coupled to an interior surface, or exterior surface, or both interior and exterior surfaces of the translucent lamp shell material. Examples of light diffusing films includes mylar or acetate, or similar films. Other examples of light diffusing film include films that have varying degrees of opacity. In another implementation, the lamp shell has a light diffusing property when the lamp shell includes a roughened surface, which scatters light. In a specific implementation, the lamp shell includes randomly sized and randomly placed particles on a surface of the lamp shell. In another specific implementation, particles can be of sizes large enough to be visible to the eye. In another specific implementation, the lamp shell includes a matting agent. The matting agent can blur spots of relatively more intense light produced by individual light sources. Examples of a matting agent can include silica powder, calcium carbonate powder, alumina powder, or the like. In a further implementation, the matting agents can have a particle size of approximately 1 to 5 microns. In an implementation, the light diffusing material is positioned over all of the exterior lighting sources so that all of the light from the exterior lighting sources will enter the light diffusing material and exit as an even glow that is spread across the entire surface of the shell. In a specific implementation, the light diffusing material is applied over an entire inner surface of the shell. In another implementation, the light diffusing material is applied over an outer surface of the shell. In another implementation, the light diffusing material is positioned over a portion of the exterior lighting sources. A portion of the light will enter and exit the light diffusing material and a portion of the light will not enter the light diffusing layer. This can result in various glow patterns across the shell the nail lamp. Each glow pattern can have a functional purpose, such as using a certain glow pattern to show when customers are close to finishing curing their gel nail polishes. In an implementation, a greater portion of the lamp shell's exterior surface area includes light diffusing property (or light diffusing material) than a portion that does not have light diffusing property. In another implementation, the lamp shell's exterior surface includes a portion with light diffusing property and an opaque portion, which does not let light travel through. In a specific implementation, the portion of the lamp shell's exterior surface that includes light diffusing property ranges from 10 percent to 100 percent. The remaining portion of the lamp shell's exterior surface is opaque. In another implementation, the lamp shell's exterior surface includes a portion with light diffusing property, a transparent portion, and an opaque portion. In an implementation, the nail lamp housing includes a first layer with light diffusing properties that is coupled to a second layer of material, which blocks out light. In a specific implementation, the light blocking material can block out specific wavelengths of light, such as UV light. Some of the interior light sources can emit UV light. Though the interior light sources are directed into the cavity (or interior space), some light rays may reflect off the inner walls of the cavity and be emitted through the shell of the nail lamp. To prevent the UV light from emitting through the shell, a layer of UV light blocking material can be added to the housing. Examples of materials that block out UV light are polycarbonate, acrylic, acrylic glass, and the like. In an implementation, the exterior light sources are positioned in regions of rather than the entire device. For example, the exterior lights can be positioned along an outer perimeter of the device. When the light is transmitted through and scattered by the translucent outer cover, the regions closest to the light sources will glow brighter than the regions farther away from the light sources (e.g., a top region of the outer cover). Typically, the LEDs for the exterior lighting are not the same wavelength as the interior lighting. In an implementation, the exterior lights are non-UV lights. In an implementation, these lights can produce visible colored light, all the same color, such as in blue. Other colors can include pink, orange, yellow, red, green, or purple or others. In other implementations, there can be different colors of exterior light (such as blue and yellow, or red and green). In other implementations, the lights are LEDs such as RGB LEDs that can produce changing colors of light during curing. FIG. 45 shows a perspective view of an exterior of a nail lamp. The display shows 44 seconds has elapsed or is remaining of the selected 60 seconds. Once the time expires, the UV lights, along with the lights of the housing, will turn off. FIG. 46 shows a top perspective view of an exterior of a nail lamp that is turned on (i.e., curing mode). A timer displays 20 seconds (or 2 seconds) has elapsed or is remaining of the selected 60 seconds. UV lights on an inside of the housing are turned on, and glow from an opening of the housing of the lamp. A specific process flow for operating a UV nail lamp is presented in table C below. It should be understood that the invention is not limited to the specific flows and steps presented. A flow of the invention may have additional steps (not necessarily described in this application), different steps which replace some of the steps presented, fewer steps or a subset of the steps presented, or steps in a different order than presented, or any combination of these. Further, the steps in other implementations of the invention may not be exactly the same as the steps presented and may be modified or altered as appropriate for a particular application. TABLE CStepFlow1Power on UV lamp.2Select curing mode. This can include a user selecting a cursing time, or a level of curing, or other parameters from a preset options (e.g., menu or buttons). The use can also manually input a desired curing time or level of curing (e.g., buttons, dial, knob, or menu). In an implementation, the user presses one of a plurality of buttons to select a predetermined curing time (e.g., 15 seconds, 30, seconds, and 60 seconds). A display can display the selected curing time or setting. Lights between an insde of the housing and an outer cover of the housing will light up, causing the housing to light up or glow during curing.3A user inserts a hand (or foot) into the housing. The user's hand can rest on a finger plate. The finger plate can have finger indicator members that allow the user to feel where to rest the fingertips.4Timer starts when the user's hand is inside the housing. As the timer starts, UV light sources within the housing turn on toirradiate the user's nails.5Timer stops after the selected time expires. When the timer stops, the UV light sources turn off. Lights between the inside of the housing and the other cover of the housing will turn off, causingthe housing to dim.6User removes hand from the housing.7Power off UV lamp. FIG. 47 shows a block diagram of a specific implementation a nail lamp that is adapted to be used with a power source that is external to the nail lamp. The nail lamp includes a shell 4702 (also referred to as an exterior surface) and an enclosure 4704 (also referred to as a cavity or interior space), which is defined by an upper surface 4706 (also referred to as inner wall of a nail lamp's housing) of the enclosure. A user can place a hand inside the enclosure. A removable finger plate 4708 can optionally attach to the nail lamp and further define the enclosure. A power circuit 4710, inside the lamp, is coupled to an external battery 4712 or an adapter 4714, both of which are outside of the nail lamp. The external battery can be connected to a charger 4716. The adapter can be connected to an external power supply (e.g., a wall outlet). The external battery or external power supply provides power to a power circuit. The power circuit provides power to sensors 4718, one or more interior LEDs 4720, a control circuit 4722 that includes a control unit 4724 and a timer display 4726, and one or more LED units 4728 that include exterior LEDs 4730 and interior LEDs 4720. The interior LED can also be referred to as an interior lighting source, discussed above, and used to cure the gel polish. The exterior LED can also be referred to as an exterior lighting source, discussed above, and produces light to indicate that the interior LED is activated. A button 4732, located outside of the shell, is connected to the control circuit. When pressed, the button activates the control circuit that controls the timer display and activates one or more SMD interior LEDs 4720 or LED units 4728. Heat sinks can be coupled to the interior LEDs within the shell. The heat sink can absorb heat given off by an activated LED so that a user's hand will not feel hot and uncomfortable inside the nail lamp. The power circuit can optionally include an internal battery 4734. The internal battery can be charged by connecting to an external battery or an adapter that is connected to an external power source such as a wall outlet. After the internal battery has been charged by the external battery or external power supply, the nail lamp can operate without being connected to an external battery or adapter. The power circuit can also include a switch between the internal battery and external power connections (e.g., such as connection to an external battery or wall outlet) to allow the nail lamp to switch between internal and external power sources. FIGS. 48-50 show an implementation of a nail lamp 4802 that includes a battery input port 4804 (also referred to as a power input) so that the nail lamp can be used with a rechargeable battery pack that is external to the housing of the nail lamp. The rechargeable external battery 4806 can provide power to the nail lamp. The external battery can be removably coupled to a cable 4808, which is removably coupled to the battery input port. FIG. 48 shows a block diagram of nail lamp 4802. FIG. 49 shows a side view of the nail lamp including the external battery attached to the nail lamp via the cable. FIG. 50A shows a first short side of the external battery. FIG. 50B shows a second short side of the external battery. FIG. 50C shows a first long side of the external battery. FIG. 50D shows a top face of the external battery. The external battery supplies power to the nail lamp. With an external battery coupled to the nail lamp and providing power, the nail lamp does not have to be coupled to a wall outlet or laptop for power supply, the nail lamp can be moved around a room to any location. To charge the external battery, the external battery can be connected to an adapter, which can be connected to a wall outlet. The external battery can also be charged by being connected to a charging dock. After the external battery is charged, it can be disconnected from the adapter or dock and coupled to the nail lamp. FIG. 51 shows a block diagram of a charging dock 5102 and an external battery 5104. The charging dock includes a battery dock 5106 for the external battery, and optionally a latch 5108 to prevent the battery from falling out of position in the battery dock. Once the external battery is inserted into the battery dock, the charging dock starts charging it. The charging dock stops charging the external battery after the battery is removed. The charging dock can be connected to a power supply via a cable 5110 that can be connected to an adapter 5112, which can be connected to the power supply (e.g., a wall outlet). FIGS. 52-54 show an implementation of a nail lamp 5202 including a battery dock attachment 5204 that can be removably coupled to an exterior of the nail lamp. FIG. 52 shows a block diagram of the nail lamp and the battery dock attachment. FIG. 53 shows a side view of the nail lamp and the battery dock attachment attached to the nail lamp. FIG. 54 shows a side view of the nail lamp with the battery dock attachment detached from the nail lamp. The battery dock includes a slot for a battery 5208 and a latch 5210 to hold the battery firmly to the battery dock. The latch can be, for example, a spring loaded release latch. The battery can be inserted into the slot. The battery dock attachment provides for easy removal of the battery when the battery needs to be recharged. FIGS. 55-57 show an implementation of a nail lamp 5502 that includes an internal battery dock 5504 where a rechargeable battery pack 5506 can integrate with the housing of the nail lamp. The internal battery dock is removably coupled to a battery 5506 to be removably coupled within the housing of the nail lamp. FIG. 55 shows a block diagram of the nail lamp including the internal battery dock. FIG. 56 shows a specific implementation of nail lamp 5502 in which the internal battery dock is located at a bottom 5606 of the nail lamp. The battery can be inserted into the bottom of the nail lamp. In other implementations, the battery dock can be located elsewhere, such as the top or side of the nail lamp, for easy access to the battery dock. The internal battery dock optionally includes a latch 5508 to hold the battery firmly to the battery dock. The latch can be, for example, a spring loaded release latch. The battery can be inserted into the slot. FIG. 57 shows a perspective view of the battery. The battery can include leads (e.g., copper strips) or pins that interface with the battery dock. FIG. 58 shows a specific implementation of an interior lighting source unit 5801. The interior lighting source unit includes at least one UV wavelength (which is approximately 100-400 nanometers) light source and at least one LED. The LED can produce light of a wavelength that is same or different from that produced by a UV wavelength light source. In a specific implementation (shown in FIG. 59), four UV light sources and one LED can be arranged such that the one LED lighting source 5803 is in the middle and the UV light sources 5805 surround the LED lighting source on four sides, like a rectangle, or square, or diamond shape. FIG. 59 shows another arrangement 5901 where three UV lighting sources surround one LED lighting source in a triangle shape. In a specific implementation, the LED produces light of 405 nanometers and can be 1-3 Watt LEDs. In another specific implementation, the UV lighting source produces light of 365 nanometers. FIG. 60 shows a strip 6001 of interior lighting source units 6002 and a magnification (indicated by broken line 6003) of one of the interior lighting source unit. An LED 6004 is adjacent to another LED 6006. The LEDs produce light of different wavelengths from each other. In a specific implementation, LED 6004 produces light of 405 nanometers, which can be used to cure LED gel. And LED 6006 produces light of 365 nanometers, which can be used to cure UV curable gel or extension gel. This arrangement of UV and LED light sources allow for universal usage of the nail lamp because the nail lamp can be used to cure both LED and UV-curable gel polish. In a further implementation, the nail lamp can be an inductive nail lamp, which the power required to generate light is transferred from outside the nail lamp to the gas inside via an electric or magnetic field. A benefit to an inductive nail lamp is extended lamp life. This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims. |
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042696615 | description | Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIGS. 1 and 2 the upper portion of a fuel assembly 10 including multiple fuel rods 12 and control guide tubes 14 held in spaced relationship with each other by multiple grids 16 disposed along the fuel assembly length. The fuel assembly is supported on a bottom nozzle and lower core plate, not shown, in accordance with conventional practices. As shown in FIG. 3, the top nozzle includes a number of guide tube extensions 18, one for each control rod guide tube, each of which is threaded at its bottom end into orifice plate 20 and secured firmly in place by welds 22. In order to firmly anchor the control rod guide tubes 14 to the top nozzle, FIG. 3, the guide tube extension is provided with a pair of spaced grooves 24 and the control rod guide tube 14 inserted thereinto is squeezed into the openings or grooves 24 which deforms the metal and thus provides an inseparable fit between the parts. The upper end of the guide tube extensions 18 extend through corresponding openings formed in a hold-down plate 26, FIGS. 1 and 2, which also include flow channels 42 through which coolant flows after cooling the fuel assembly. The ends of the guide tube extensions also project upwardly into upper core plate 28. Helical springs 30 are concentrically disposed on the guide tube extensions and bear at their lower ends against the orifice plate 20 and at their upper ends against the hold-down plate 26, thus urging the hold-down plate into contact with the lower surface of upper core plate 28. It will be noted that the upper core plate 28 includes a substantially large opening 32 into which the guide tube extensions extend. It further will be understood that control rods 33 are adapted for vertical movement in the control rod guide tubes 14 during the course of controlling reactor operation. In order to limit the upward movement of the fuel assembly 10, each of the guide tube extensions is equipped with an axially extending slot 34, FIG. 4, in which a pin 36 is adapted to ride when the fuel assembly is moved upwardly. The plan view of the assembly shown in FIG. 2 more clearly shows the design of the hold-down plate 26 and how the pins 36 are adapted to ride in the slots 34 located in each of the four corner guide tube extensions 18. As more clearly shown in FIGS. 2 and 5, the central control rod guide tube extension 18 located in the center of the four corner guide tubes carries a pair of oppositely disposed slots 38 and corresponding pins 40 in the hold-down plate 26. The large number of openings 42 formed by ligaments 44 are utilized to facilitate the flow of coolant through the fuel assembly. In practice, the axis of fuel rods will lie immediately below the ligaments in order to eliminate the possibility of a fuel rod being ejected from the fuel assembly in the event it encounters unusually heavy coolant flows or other forces which may move a fuel rod upwardly relative to the fuel assembly components. In operation, after all the fuel assemblies have been set in position in the reactor, the upper core plate 28 is lowered into position such that its lower surface 46 engages the upper surface of hold-down plate 26. In so doing, the springs are compressed to a slight degree thereby applying a downward force on the orifice plate 20 and control rod guide tubes 14. The guide tubes 14 transmit this load through the lower nozzle to the base of the reactor. The design of the springs and the distance between the orifice plate and hold-down plates are chosen such that the springs will never be fully compressed during reactor operation. In the event a heavy hydraulic lifting force is applied to the fuel assembly, the complete fuel assembly will move upwardly thus compressing springs 30 and causing the pins 36 and 40 respectively to ride in their slots 34 and 38 formed on the guide tube extensions. The springs therefore will absorb the lifting forces and transmit the same through the hold-down plate 26 and into the upper core plate 28 for further distribution through the internal structure of the reactor. As the assembly moves upwardly and thus compresses the springs, the guide tube extension slots will ride on the pins until, for each outer guide tube extension, the bottom of the slot is contacted by the pin, and for the center guide tube extension the bottom surface of the hold-down plate is contacted by the upper surface of the center guide tube extension shoulder 39. Since this will uniformly occur in all of the guide tube extensions, uniform loading of the guide tubes will occur but only after the springs have been compressed to the desired degree. As indicated previously, the springs have a constant such that they never are compressed to the point where all coils in each spring contact one another since this then would involve a solid structure which is intended to be avoided. The modification of FIG. 6 illustrates an arrangement where pads 50 are used at each of the four corners of the assembly, and at the center, where each control rod guide tube extension 18 projects upwardly through the hold-down plate 26. Each of these pads on the orifice plate 20 project upwardly a slight distance while the bottom surface of the hold-down plate likewise has four downwardly projecting pads 52 arranged to contact the lower pads when the fuel assembly is lifted. These nozzle pads limit the amount of fuel assembly lift in the event of an accident, such as a blow down and the four corner pads provide lead in chamfers 54 for fuel handling. The nozzle pads are sized such that they contact the hold-down plate prior to the springs being compressed solid and thereby present the nozzle guide tube extensions from topping out in the blind holes in the upper core plate. This arrangement helps assure uniform loading of the guide tubes during any accident which causes fuel assembly lift. It will be apparent that many modifications and variations are possible in light of the above teachings. It therefore is to be understood that within the scope of the appended claims the invention may be practiced other than as specifically described. |
052934101 | claims | 1. A neutron generator comprising: (i) an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment; (ii) means for heating said cathode so that the latter emits electrons which, when colliding with said gas atoms, generate ions; (iii) a target; (iv) an electrical gap to accelerate ions from said ion source towards said target upon impingement of said ions; and (v) control means for applying voltages to said anode, cathode and electrical gap, wherein a voltage applied to said anode by said control means is between 100 and 300 Volts to substantially reduce metal sputtering within the neutron generator. an ion source comprising an anode and a dispenser or volume type cathode disposed in an ionizable gas environment including at least one hydrogen isotope; means for heating said cathode so that the latter emits electrons which, when colliding with said gas atoms, generate ions; a target; an electrical gap to accelerate ions from said ion source towards said target upon impingement of said ions; and control means for applying voltages to said anode, cathode and electrical gap, wherein a voltage applied to said anode by said control means is between 100 and 300 Volts to substantially reduce metal sputtering within the neutron generator. (i) an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment; (ii) means for heating said cathode so that the latter emits electrons which, when colliding with said gas atoms, generate ions; (iii) a target; (iv) an electrical gap to accelerate ions from said ion source towards said target upon impingement of said ions; and (v) control means for applying voltages to said anode, cathode and electrical gap, wherein a voltage applied to said anode by said control means is between 100 and 300 Volts to substantially reduce metal sputtering within the neutron generator. a source of ionizable gas; an ion source for ionizing said gas and including an anode and a dispenser type cathode designed to emit electrons able to impinge on gas atoms so as to generate ions; a target spaced apart from said ion source by an accelerating gap, and being able to emit neutrons upon impingement of ions issued from said ion source; control means for applying voltages to said anode, cathode and electrical gap; and means for operating said control means such that the rise time for the neutron output to reach 90% of the maximum output plateau), measured from the time when the neutron output is 10% of said plateau, is less than 1 microsecond. a source of ionizable gas; an ion source for ionizing said gas and including an anode and a dispenser type cathode designed to emit electrons able to impinge on gas atoms so as to generate ions; a target spaced apart from said ion source by an accelerating gap, and being able to emit neutrons upon impingement of ions issued from said ion source; control means for applying voltages to said anode, cathode and electrical gap; and means for operating said control means such that the time lag between the instant when the voltage is applied to said cathode and the instant time when the instantaneous neutron output reaches 10% of the maximum output (plateau), is less than 0.5 microsecond. a source of ionizable gas; an ion source for ionizing said gas and including an anode and a dispenser type cathode designed to emit electrons able to impinge on gas atoms so as to generate ions; a target spaced apart from said ion source by an accelerating gap, and being able to emit neutrons upon impingement of ions issued from said ion source; control means for applying pulsing voltages to said anode, cathode and electrical gap; and means for operating said control means such that the neutron output reaches a maximum value (or plateau) which remains constant within a 10% range thereof, over a pulse time width comprised between 18 and 25 microsecond. a source of ionizable gas; an ion source for ionizing said gas and including an anode and a dispenser type cathode designed to emit electrons able to impinge on gas atoms so as to generate ions; a target spaced apart from said ion source by an accelerating gap, and being able to emit neutrons upon impingement of ions issued from said ion source; control means for applying voltages to said anode, cathode and electrical gap; and means for operating said control means such that the fall time between the instant when the voltage applied to said cathode is turned off and the instant time when the instantaneous neutron output falls to 10% of the maximum output (plateau), is less than 0.5 microsecond. a source of ionizable gas; an ion source for ionizing said gas and including an anode and a dispenser type cathode designed to emit electrons able to impinge on gas atoms so as to generate ions; a target spaced apart from said ion source by an accelerating gap, and being able to emit neutrons upon impingement of ions issued from said ion source; control means for applying voltages to said anode, cathode and electrical gap; and means for operating said control means such that the time required for the instantaneous neutron output to reach its maximum (plateau) value, measured from the instant time when the voltage is applied to said cathode, is less than 1.5 microsecond. irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the dispenser cathode; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output during the start of the neutron burst such that the rise time for the neutron output to reach 90% of its plateau, measured from the time when the neutron output is 10% of the plateau, is less than 1 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. generating bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the cathode; irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron burst during the start of the neutron burst such that the time lag between the instant when the voltage is applied to the cathode and the instant time when the instantaneous neutron output reaches 10% of its plateau, is less than 0.5 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the dispenser cathode; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output such that the neutron output reaches a plateau which remains constant within a 10% range thereof, over a burst time width comprised between 18 and 25 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. generating bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the cathode; irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output such that the fall time between the instant when the voltage applied to the cathode is turned off and the instant time when the instantaneous neutron output falls to 10% of its plateau, is less than 0.5 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. generating bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating cathode; irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output during the neutron burst such that the time required for the instantaneous neutron output to reach a plateau, measured from the instant time when the voltage is applied to the cathode, is less than 1.5 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. generating bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the cathode; irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output such that: (i) the rise time for the neutron output to reach 90% of its plateau, measured from the time when the neutron output is 10% of the plateau, is less than 1 microsecond; (ii) the fall time between the instant when the voltage applied to the cathode is turned off and the instant time when the instantaneous neutron output falls to 10% of the plateau, is less than 0.5 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. generating bursts of neutrons from a neutron generator including an ion source comprising an anode and a dispenser cathode disposed in an ionizable gas environment, by applying voltage pulses to the cathode and heating the cathode; irradiating, at a first given location in the borehole, the borehole materials and the earth formation with bursts of neutrons; detecting, at a second given location in the borehole, radiation resulting from interaction of the neutrons with the formation; generating signals representative of the radiation; controlling the neutron output such that: (i) the rise time for the neutron output to reach 90% of its plateau, measured from the time when the neutron output is 10% of the plateau, is less than 1 microsecond; (ii) the fall time between the instant when the voltage applied to the cathode is turned off and the instant time when the instantaneous neutron output falls to 10% of its plateau, is less than 0.5 microsecond; and (iii) the neutron output reaches a plateau which remains constant within a 10% range thereof, over a pulse time width comprised between 18 and 25 microsecond; and determining from the signals a characteristic of the earth formation surrounding the borehole. 2. The neutron generator according to claim 1, wherein said gas comprises at least one hydrogen isotope. 3. The neutron generator according to claim 2, wherein said gas environment constitutes a sealed chamber. 4. The neutron generator according to claim 1, wherein said cathode comprises at least one block of material comprised of a substrate impregnated with an electron emitting material. 5. The neutron generator according to claim 4 wherein said substrate is tungsten and said emitter material includes barium oxide. 6. The neutron generator according to claim 1, wherein said voltages are in the form of square voltage pulses. 7. The neutron generator according to claim 1 wherein said voltage applying means for said cathode is distinct from said cathode heating means. 8. The neutron generator according to claim 1, wherein said anode is made of a hollow elongated body permeable to electrons. 9. The neutron generator according to claim 8, wherein said anode is made of a cylindrical metallic coil. 10. The neutron generator according to claim 8, wherein said anode is made of a cylinder-shaped mesh. 11. The neutron generator according to claim 4, wherein said block is disposed at one end of an arm connected to said heating means and to said control means. 12. The neutron generator according to claim 8, wherein said cathode is disposed inside said anode. 13. The neutron generator according to claim 8, wherein said cathode is disposed outside said anode. 14. The neutron generator according to claim 11 wherein said cathode comprises two arms disposed diametrically on the outside of said anode. 15. The neutron generator according to claim 1, further comprising an extracting electrode disposed at the end of said ion source facing said target and submitted to a voltage complementary to the anode voltage. 16. The neutron generator according to claim 15, wherein the end of said extracting electrode facing said target is torus shaped. 17. The neutron generator according to claim 6, further comprising means for preventing slows ions, still present in said ion source at the end of said voltage pulse, from leaving said ion source. 18. The neutron generator according to claim 17 wherein said preventing means comprises a cut-off electrode disposed at the end of the ion source and which is submitted to voltage pulses synchronized with and complementary to pulses applied to said anode, and to a positive voltage between said pulses. 19. The neutron generator according to claim 18 wherein said cut-off electrode includes a mesh screen. 20. The neutron generator according to claim 19 wherein said mesh screen is in the form of a truncated sphere having its concavity facing said target. 21. The neutron generator according to claim 17 wherein said preventing means comprises means for applying to said extracting electrode negative voltage pulses synchronized with pulses applied to said anode, and a positive voltage between said pulses. 22. The neutron generator according to claim 3 comprising a cylindrical insulator disposed between said ion source and said target. 23. The neutron generator according to claim 22 wherein said insulator is made of ceramic. 24. The neutron generator according to claim 1 wherein said gas environment comprises a gas supply means incorporating a helical filament coated with material able, when heated, to emit atoms of at least one hydrogen isotope and disposed transversely to the longitudinal axis of the accelerating gap. 25. The neutron generator according to claim 23 wherein the gas pressure in said gas environment is comprised between 0.5 milliTorr and 20 milliTorr. 26. A neutron generator comprising: 27. A logging tool for investigating earth formations surrounding a borehole, comprising a sonde incorporating at least one radiation detector and a neutron generator, said neutron generator comprising: 28. A neutron generator for logging applications, comprising: 29. A neutron generator for logging applications, comprising: 30. A neutron generator for spectral logging applications, comprising: 31. A neutron generator for logging applications, comprising: 32. A neutron generator for spectral logging applications, comprising: 33. A method for investigating earth formation surrounding a borehole, comprising the steps of: 34. A method for investigating earth formation surrounding a borehole, comprising the steps of: 35. A method for investigating earth formation surrounding a borehole, comprising the steps of: 36. A method for investigating earth formation surrounding a borehole, comprising the steps of: 37. A method for investigating earth formation surrounding a borehole, comprising the steps of: 38. A method for investigating earth formation surrounding a borehole, comprising the steps of: 39. A method for investigating earth formation surrounding a borehole, comprising the steps of: |
051665310 | summary | BACKGROUND OF THE INVENTION This invention relates to a multileaf collimator for use in a radiation system used to shape and control spatial distribution of the radiation field intensity. Conventional radiation treatment of a tumor in a patient is carried out by planning the radiation beam angles and dosage, taking into consideration safety factors with respect to the patient's normal tissue and organs located in the path of the proposed radiation beam. The usual treatment field shapes result in a three-dimensional treatment volume which includes segments of normal tissue and organs (a safety margin around the tumor), thereby limiting the dose that can be given to the tumor. Cure rates for many tumors are a sensitive function of the dose they receive. The dose that can be delivered to the tumor can be increased if the portion of the normal tissue or organs receiving dose can be reduced. Techniques are under development to make the treatment volume conform more closely to the shape of the tumor volume. This permits higher dose to tumors and less damage to normal tissue and organs, with its attendant positive effects on the health of the patient. The techniques typically involve moving the jaw-blocks during treatment, scanning the radiation beam over the volume to be treated or using a multileaf collimator. Multileaf collimators can provide a similar function as the conventional jaw-blocks. In addition, each individual segment or leaf in a multileaf collimator is usually independently positionable. The radiation beam is directed at the ends and sides of the collimator leaves such that the beam is limited to the desired treatment area to be irradiated, while shielding the normal tissue and organs. Radiation beam penumbra occurs in systems equipped with multileaf collimators at the edges of the radiation field where the radiation intensity decreases with distance from the full intensity region of field. This phenomenon is a combination of geometric penumbra due to the radiation source size and transmission penumbra due to penetration of the radiation beam through the ends of the multileaf collimator leaves. Geometric penumbra is a function of the source size, the thickness of the leaves, the distance of the leaves from the source and the distance of the reference plane from the source. Transmission penumbra is a function of material the leaves are made from, the thickness of the leaves and the energy of the radiation beam. In the technical paper, "Design Principles of Telecobalt Collimators", W. H. Sutherland and C. W. Smith, Physics in Medicine and Biology, 22, 1189-1196 (1977), the authors clearly show that minimum geometric penumbra is produced when radiation collimators are pointed at the side of the radiation source. The penumbra produced by square-end or simple curved-end linear-motion multileaf collimators at points equidistant from the central axis of the radiation beam is not equal. This can be explained as an effect of geometric penumbra. When the leaf is fully retracted from the central axis, the radiation field is defined by the portion of the leaf end furthest from the radiation source, the distal portion. In the fully extended position, the portion of the leaf end closest to the radiation source defines the radiation field, the proximal portion. The proximal portion of the extended leaf end produces greater geometric penumbra than the distal portion of the retracted leaf for positions equidistant from the central axis of the radiation field because the radiation source is perceived as larger from the proximal portion. Typically, megavoltage radiation beams are very penetrating. Collimators and jaw-blocks that are used to sharply define the shape of radiation beam are typically made from high density, high atomic number materials and are usually several inches thick. If thinner sections, with less attenuation, are used then the edge of the radiation field is not defined as sharply, hence the transmission penumbra is larger. U.S. Pat. No. 4,672,212 to Brahme discloses a multileaf collimator in which the entire leaf body is curved. The curved leaf follows a curved path of travel such that the flat leaf end is always tangent to the radius of an imaginary circle having its center at the radiation source. This configuration minimizes transmission penumbra. However, the curved leaf body results in complicated leaf mounting structures which are mechanically complex, physically large, difficult to retrofit onto existing systems and expensive to manufacture. Linear motion multileaf collimators or jaw-blocks are easier to fabricate and assemble but their use typically produces larger penumbra. Leaf ends having simple curves of large radius produce acceptable penumbra for small field sizes. However, the transmission penumbra becomes progressively worse for larger fields. Leaf ends having small radii produce large penumbra for all field sizes. Also, penumbra for leaf ends at equidistant positions about the central axis are not equal. The technical paper, "Analysis of the Field-Defining Properties of a Multileaf Collimator", N. Maleki and P. Kijewski, Medical Physics, 10, 518 (abstract) (1983), contains a figure which shows calculated penumbra for a range of simple, curved leaf-ends with a constant radius. A figure from the paper is reproduced here as FIG. 6. As discussed above, leaf ends having curves of large radius produce acceptable penumbra for small field sizes. However, the penumbra becomes progressively worse for larger fields. Leaf ends having curves of small radius produce large penumbra for all field sizes. U.S. Pat. No. 4,868,843 to Nunan issued on Sep. 19, 1989, assigned to the assignee of the present invention, is hereby incorporated by reference thereto. Nunan discloses a multileaf collimator assembly which can be retrofitted as an accessory to existing systems. Alternatively, the Nunan multileaf collimator may be incorporated into the design of a new radiation system. The multiple leaves are independently positionable and travel in a straight line along the longitudinal axis of the individual leaves. This patent incorporates leaves with simple curved ends. U.S. Pat. No. 4,534,052 to Milcamps describes a linear-motion jaw-block having a curved end. The jaw-block is movable only in a retractable direction with respect to the central axis of the radiation beam. The curved jaw-block end is defined by a simple arc of large radius having a center of curvature positioned on the proximal jaw-block surface, closest to the radiation source. The radiation beam of Milcamps is defined by a sharp edge at the intersection of the "active surface" and the distal surface when the jaw-block is at the furthest retracted position from the central axis of the radiation beam. This sharp edge readily transmits the penetrating radiation beam causing excessive transmission penumbra. Additionally, the asymmetric jaw-block "active surface" produces unacceptable penumbra if extended beyond the central axis of the radiation beam, by transmission of penetrating radiation through the sharp edge, at the intersection of the proximal surface, closest to the radiation source, and the "active surface". SUMMARY OF THE INVENTION The present invention relates to a multileaf collimator for use in a radiation system which provides uniform, minimized penumbra over the full range of travel of the collimator leaves, including travel across central axis of the radiation beam. In radiation therapy systems equipped with multileaf collimators, the multileaf collimator is contained within or attached to the radiation head. Irregular field shapes, conforming to the prescribed treatment volume, are established by moving the leaves to the desired positions. The present invention is preferably used in conjunction with a plurality of elongated collimator leaves arranged in a side-by-side array. Two such arrays are positioned with the leading ends of each array facing the other in opposed relationship on opposite sides of the central axis of the radiation beam. It is an object of the present invention to equalize geometric penumbra and transmission penumbra over the full range of leaf end travel by optimizing the amount of material used to define the edge of the radiation beam. The proximal portion of the leaf-end, with greater geometric penumbra, is preferably given more material to define the radiation field. This greater attenuation more sharply defines the edge of the field, hence produces smaller transmission penumbra values. Conversely, material is also preferably taken away from the distal portion of the leaf-end, which has smaller geometric penumbra, causing it to produce less sharply defined radiation field edges, hence greater transmission penumbra. The penumbra produced by the distal and proximal portions of the leaf end will, therefore, be similar for points equidistant from the central axis of the radiation beam. This equalization of geometric and transmission penumbra is achieved by distally offsetting the axis of symmetry of each respective collimator leaf end with respect to the longitudinal axis of the leaf. Thus, it will not be necessary for the treatment planner of the radiation system to differentiate between retraction or extension of the collimator leaves. In addition, it is an object of the present invention to minimize penumbra. This is accomplished by pointing the proximal and distal tangential leaf end surfaces at the edge of the radiation source. The minimized penumbra will allow the treatment field to more closely conform to the tumor volume. Other features and advantages of the present invention will appear from the following descriptions in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawings. |
abstract | Mirror substrate consisting of crystal, especially silicon crystal, on which an amorphous layer, especially a quartz glass layer, is applied. |
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claims | 1. Lead-free radiation protection material in the energy range of an X-ray tube having a voltage of from 60 to 125 kV, having a layer structure of at least two layers with different shielding properties, said at least two layers comprising a secondary radiation layer and a barrier layer, wherein the secondary radiation layer comprises tin in an amount of from 50 to 90 wt. % and at least one further element and/or compound(s) thereof of atomic numbers 39 to 60 in an amount of from 10 to 50 wt. %. 2. Lead-free radiation protection material according to claim 1, wherein the element is selected from tin, iodine, caesium, barium, lanthanum, cerium, praseodymium, neodymium and compounds thereof. 3. Lead-free radiation protection material according to claim 1, wherein the secondary radiation layer comprises tin and cerium or a compound thereof. 4. Lead-free radiation protection material in the energy range of an X-ray tube having a voltage of from 60 to 125 kV, having a layer structure of at least two layers with different shielding properties, said at least two layers comprising a secondary radiation layer and a barrier layer, wherein the barrier layer comprises at least one element of atomic numbers greater than 71 or a compound thereof and wherein said at least one element is selected from bismuth, tungsten and compounds thereof and wherein the barrier layer further comprises at least one element of atomic numbers 61 to 71 or compounds thereof. 5. Lead-free radiation protection material according to claim 4, wherein the element is selected from the group erbium, holmium, dysprosium, terbium, gadolinium, europium, samarium, lutetium, ytterbium and thulium and compounds thereof. 6. Lead-free radiation protection material according to claim 5, wherein the element is gadolinium. 7. Lead-free radiation protection material according to claim 4, wherein at least one element of atomic numbers 61 to 71 or compounds thereof is present in the form of an intermediate layer which is arranged between the secondary radiation layer and the barrier layer. 8. Lead-free radiation protection material according to claim 4, wherein the barrier layer further comprises elements of atomic numbers greater than 71 and/or their compounds in an amount of up to 80 wt. %. 9. Lead-free radiation protection material according to claim 8, wherein the amount is in a range of from 20 to 70 wt. %. 10. Lead-free radiation protection material in the energy range of an X-ray tube having a voltage of from 60 to 125 kV, having a layer structure of at least two layers with different shielding properties, said at least two layers comprising a secondary radiation layer and a barrier layer, wherein the barrier layer comprises tungsten or compounds thereof in an amount of from 0 to 30 wt. % and/or bismuth or compounds thereof in an amount of at least 30 wt. %. 11. Lead-free radiation protection material according to claim 7, wherein the secondary radiation layer and/or the intermediate layer and/or the barrier layer comprise(s) at least one pure-material layer. 12. Lead-free radiation protection material according to claim 11, wherein the pure-material layers are greatly compressed. 13. Lead-free radiation protection material according to claim 12, wherein the pure-material layers are compressed to more than 75 vol. %. 14. Lead-free radiation protection material according to claim 13, wherein the pure-material layers are compressed to more than 90 vol. %. 15. Lead-free radiation protection material according to claim 14, wherein the greatly compressed pure-material layers are in the form of metal foils. 16. Lead-free radiation protection material according to claim 15, wherein the metal foils have a thickness of from 0.005 to 0.25 mm. 17. Lead-free radiation protection material according to claim 16, wherein the metal foils are foil strips or foil plates. 18. Lead-free radiation protection material according to claim 11, wherein the at least one pure-material layer has a carrier layer on one side. 19. Lead-free radiation protection material according to claim 11, wherein the at least one pure-material layer has a carrier layer on both sides. 20. Lead-free radiation protection material according to claim 18, wherein the carrier layers are formed by a polymer. 21. Lead-free radiation protection material according to claim 20, wherein the polymer is a latex or elastomer polymer. 22. Lead-free radiation protection material according to claim 20, wherein the carrier layers have a thickness of from 0.01 to 0.4 mm. 23. Lead-free radiation protection material according to claim 18, wherein the carrier layers comprise small amounts of protective substances. 24. Lead-free radiation protection material according to claim 11, wherein the pure-material layers of the protective foil are so composed that the layers are arranged according to increasing secondary radiation. 25. Lead-free radiation protection material according to claim 11, wherein each layer having high secondary radiation has on both sides a layer having low secondary radiation. 26. Radiation protection clothing of a lead-free radiation protection material according to claim 1. 27. Radiation protection clothing according to claim 26 in the form of an apron. 28. Radiation protection clothing of a lead-free radiation protection material according to claim 4. 29. Radiation protection clothing according to claim 28 in the form of an apron. 30. Radiation protection clothing of a lead-free radiation protection material according to claim 10. 31. Radiation protection clothing according to claim 30 in the form of an apron. |
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051026139 | summary | CROSS-REFERENCE TO RELATED APPLICATION The present invention is related to U.S. patent application Ser. No. 07/559,743, filed 30 July 1990, entitled "Brake Assembly for a Control Rod Drive," by K. J. Jamrus et al, commonly owned by the present assignee. TECHNICAL FIELD The present invention relates generally to control rod drives used in nuclear reactors and, more specifically, to a brake assembly effective for preventing rotation of the control rod drive when engaged. BACKGROUND ART In one type of nuclear reactor, control rods are selectively inserted and withdrawn from a nuclear reactor vessel for controlling the operation thereof. Each of the control rods is typically positioned by a conventional control rod drive which includes a ball screw or spindle operatively engaging a ball nut for raising and lowering the ball nut as the spindle is rotated either clockwise or counterclockwise. A hollow piston rests upon the ball nut at one end thereof and at its other end is conventionally joined to the control rod. Displacement of the ball nut provides displacement of the hollow piston which in turn inserts or withdraws the control rod in the reactor vessel. In order to achieve faster insertion of the control rod than could be obtained by normal rotation of the ball spindle, which is conventionally referred to as a scram operation, a rapid flow of high-pressure water is injected through the control rod drive past the piston for lifting the piston off the ball nut in a relatively short time for quickly inserting the control rod into the reactor vessel. The high-pressure water is channeled to the control rod drive through a scram line pipe attached to a high-pressure water accumulator. In one type of occurrence which allows for rapid backflow of the water past the piston, due to, for example, a break in the scram line, the backflow may cause a large reverse pressure on the piston which in turn provides a back force on the control rod ball nut. This back force can cause reverse rotation of the ball spindle with corresponding withdrawal of the control rod. Withdrawal of one of the control rods due to such a backflow occurrence may cause damage to adjacent fuel in the reactor vessel, requiring replacement thereof leading to undesirable down time of the reactor and economic losses. In order to prevent the above occurrence, a conventional electromechanical brake is provided in the control rod drive for holding the ball spindle from rotating unless the brake is energized. The brake is sized for restraining rotation of the ball spindle against such forces due to backflow of water over the piston when the control rod drive motor is not operating. And, when the control rod drive motor is operating, the motor itself is sized for providing adequate torque for resisting the forces due to the backflow of water in the event of the above-described occurrence. The motor is also sized to ensure that it may cause the control rod to be inserted even in the event that the brake fails in its engaged position to ensure effective control and/or shutdown of the reactor. To ensure operability of the brake, the brake is periodically tested. However, the brake is located adjacent to the reactor vessel, which is inaccessible during operation of the reactor due to the radiation field emanating from the reactor vessel. The radiation field continues at reduced levels also during shutdown of the reactor, which would require inspectors to wear suitable protective clothing and limit their time in the area. In one nuclear reactor embodiment, there are about 205 control rod drives, including a respective number of brakes, which would necessarily require a substantial amount of time for testing all of the brakes. Testing of the brakes during reactor shutdown would, therefore, be relatively costly to accomplish, which is additionally economically undesirable since the reactor is not operating for producing power. Since conventional electromechanical brakes typically utilize braking pads for restraining rotation of a rotor disc, they are subject to slippage. Slippage can result in undesirable partial withdrawal of the control rod during backflow occurrence, and also requires additional means for effectively testing the torque-resisting capability of the brake. OBJECTS OF THE INVENTION Accordingly, one object of the present invention is to provide a new and improved brake assembly for preventing rotation of a shaft. Another object of the present invention is to provide a brake assembly effective for providing a positive rotational restraint of the shaft in one direction while allowing rotation thereof in an opposite direction. Another object of the present invention is to provide a relatively simple and compact brake assembly for a shaft. Another object of the present invention is to provide a brake assembly which is relatively easily testable. Another object of the present invention is to provide a brake assembly for preventing rotation of a control rod drive for a nuclear reactor and which may be actuated and tested remotely. DISCLOSURE OF INVENTION A brake assembly is disclosed for selectively preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The brake assembly includes a stationary housing, a rotor disc fixedly connected to the shaft for rotation therewith, and a brake member disposed adjacent to the perimeter of the rotor disc. The rotor disc includes at least one rotor tooth and the brake member includes at least one braking tooth. Means are disclosed for selectively positioning the brake member in a deployed position for allowing the braking tooth to contact the rotor tooth for preventing rotation of the shaft in a first direction, and in a retracted position for allowing the rotor disc and shaft to rotate without restraint from the brake member. |
044302924 | claims | 1. In a system for disposing of radioactive gaseous wastes in a nuclear power plant of the type comprising: a steam turbine; a first condenser connected to the steam turbine; a vertically cylindrical recombining unit connected to the first condenser and comprising preheating means for preheating to a predetermined temperature radioactive gaseous wastes fed from the first condenser and catalytic recombining means which forms water vapour from oxygen and hydrogen contained in the radioactive gaseous wastes; a second condenser connected to an output of said recombining unit; and means connected to an output of said second condenser for adsorbing and holding up the radioactive gaseous wastes with an adsorbing agent; the improvement in which said recombining unit is dividable into an upper half in which said recombining means is disposed and a lower half in which said preheating means is disposed, there being a space between said recombining means and said preheating means, said second condenser being disposed downstream of and in direct contact with said recombining unit, and in which the radioactive gaseous wastes are fed from said first condenser into said recombining unit at a portion of said recombining unit near the bottom thereof and pass through said preheating means, said recombining means, and into said second condenser through a portion of said recombining unit near its upper end. |
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claims | 1. A uranium dioxide nuclear fuel pellet comprising:uranium dioxide grains; and micro-partitions partitioning and contacting the uranium dioxide grains,wherein the micro-partitions consist essentially of a ceramic material that melts in a temperature range of 1200-1800° C.,wherein the ceramic material is a mixture comprising two or more selected from the group consisting of Si-compounds, Ti-compounds, Al-compounds, Mg-compounds, and Mn-compounds, andwherein the mixture further comprises the Ti-compounds in an amount of at least 37.08 wt % or the Mn-compounds in an amount of 14.0 wt %. 2. The uranium dioxide nuclear fuel pellet of claim 1, further comprising:metallic particles dispersed in the uranium dioxide grains and configured to react with oxygen more easily than uranium dioxide does. 3. The uranium dioxide nuclear fuel pellet according to claim 2, wherein the metallic particles comprise Cr or Mo. 4. The uranium dioxide nuclear fuel pellet according to claim 2, wherein an average size of the metallic particles is about 0.3 μm to about 10 μm. 5. The uranium dioxide nuclear fuel pellet according to claim 1, wherein the micro-partitions define a plurality of microcells, wherein each of at least some of the microcells contains a single grain of uranium oxide. 6. The uranium dioxide nuclear fuel pellet according to claim 1, wherein one of the micro-partitions is located between two immediately neighboring grains of the uranium dioxide grains and contacts the two immediately neighboring grains. |
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052951693 | summary | BACKGROUND OF THE INVENTION This invention relates to reactor containment facilities and, in particular, to reactor containment facilities improved in terms of the heat dissipation characteristic of a reactor containment vessel. As disclosed in JP.A.63-75594 and JP.A.63-191096, a reactor containment vessel includes a dry well, which defines a space where a reactor pressure vessel containing a core is arranged, and a suppression chamber. The suppression chamber holds suppression-pool water and defines a wet well in the space above it, with the dry well communicating with the suppression-pool water through vent pipes. The outer periphery of this suppression chamber is surrounded by a steel wall, which constitutes the containment vessel, with the steel wall being surrounded by an outer peripheral pool containing a cooling water that is in contact therewith. In this reactor containment vessel, the coolant in the reactor pressure vessel, turned into steam that is at high temperature and pressure by being heated by the core, is conveyed from the reactor pressure vessel to the exterior of the reactor containment vessel through pipes. Any rupture in the pipes will cause some of the coolant in the reactor pressure vessel to leak into the dry well as steam at high temperature and pressure to occupy the same (a loss-of-coolant accident); then, the coolant steam will be discharged therefrom, along with the nitrogen with which the dry well has been filled, through the vent pipes into the suppression-pool water, where the steam condenses, with the nitrogen being accumulated in the wet well as noncondensing gas. The transfer of the noncondensing gas from the dry well to the wet well is completed in several minutes after the occurrence of the accident; afterwards, it is only the steam discharged from the reactor pressure vessel that flows into the suppression-pool water. The condensation of this steam causes the temperature of the suppression-pool water to be increased, generating a difference in temperature between the suppression-pool water and the outer-peripheral-pool water. Since the containment-vessel wall separating the suppression chamber from the outer peripheral pool is made of steel, which is a good conductor of heat, the above-mentioned difference in temperature causes the heat held by the suppression-pool water to be transferred to the outer-peripheral-pool water through the wall of the reactor containment vessel. Due to this arrangement, the heat in the reactor containment vessel can be discharged to the exterior thereof over a long period of time after the occurrence of the accident, without using any dynamic apparatus, with the result that a rise in pressure in the reactor containment vessel is suppressed, thereby ensuring the soundness of the reactor containment vessel. Furthermore, since it promotes the heat dissipation from the reactor containment vessel in a natural manner, without using any dynamic apparatus, the above-described containment vessel is referred to as a natural-heat-dissipation-type or natural-cooling-type containment vessel, which provides a high level of reliability since it employs no dynamic apparatus. Thus, of those reactor containment vessels endowed with a pressure-rise suppressing function to cope with a loss-of-coolant accident, which is to be taken into account from the viewpoint of safety when designing a nuclear reactor, the natural-heat-dissipation-type containment vessel, which is equipped with a cooling water pool in the outer periphery thereof, can be cooled by transferring heat from the suppression chamber to the outer-peripheral-pool water through the containment-vessel wall, thereby suppressing pressure rise in the containment vessel. When applied to a plant of a relatively large output power, this natural-heat-dissipation-type containment vessel entails, at the time of an accident, an increase in decay heat, which is discharged from the reactor core into the space in the containment vessel; this increase in decay heat is in proportion to the output power, so that it is necessary to proportionately increase the quantity of heat that can be dissipated to the exterior of the containment vessel. One method of increasing the heat dissipation from the natural-heat-dissipation-type containment vessel is to enlarge the area of the heat transfer surface through which heat is transferred from the suppression chamber to the outer-peripheral-pool water. In the case where the wall of the reactor containment vessel is used as the heat transfer surface, the heat transfer area can be increased by enlarging the diameter of the containment vessel, or increasing the water depth of the vent pipes so as to attain an enlargement in the height direction of the region which is effective in transferring heat to the outer peripheral pool. Enlarging the diameter of the reactor containment vessel, however, is not desirable since it would entail deterioration in the pressure withstanding capacity of the containment vessel, which would lead to a decrease in the allowable temperature of the suppression chamber, resulting in a degeneration in heat dissipation characteristic. Increasing the water depth of the vent pipes, on the other hand, involves an excessive swell of the suppression-pool water when a great amount of steam rapidly enters the suppression chamber at the initial stage of an accident, so that it is necessary to increase the height of the space above the pool water or augment the strength of the structures inside the suppression chamber. Thus, this method is not desirable, either. Prior-art techniques for enlarging the heat transfer area without enlarging the diameter of the containment vessel or increasing the water depth of the vent pipes, are disclosed in JP.A.64-91089 and JP.A.2-181696, according to which the outer-peripheral-pool water is circulated through pipes running through the interior of the suppression chamber, thus utilizing the heat dissipation from the pipes running through the suppression chamber as well as the natural heat dissipation through the containment-vessel wall. Another prior-art technique in this regard was presented in the "Fall Meeting of Atomic Energy Society of Japan in the Year 1989". According to the technique presented, a convection promoting plate is provided in the suppression pool to promote the pool water circulation in the lower region of the suppression pool, thereby mitigating the temperature stratification in the suppression pool; due to this arrangement, that region of the suppression pool which is effective in absorbing the heat from the nuclear reactor and the heat transfer area for heat dissipation can be enlarged in the vertical direction. According to still another prior-art technique, not only the suppression-pool water but also the wet well is cooled by utilizing the containment-vessel wall; in this prior-art technique, which is shown in JP.A.2-227699, the entire containment vessel is surrounded by a flow passage, through which air is circulated to effect cooling. The prior-art techniques mentioned above, however, have the following problems: In the prior-art techniques described in JP.A.64-91089 and JP.A.2-181696, the outer-peripheral-pool water which has been heated to high temperature by the heat released from the suppression-pool water, is allowed to circulate, so that, in the region below the vent-pipe outlets, it is always the temperature on the side of the outer peripheral pool that rises first. As a result, heat transfer takes place in that region from the outer peripheral pool toward the suppression chamber, so that the heat which has been released to the outer peripheral pool in the region above the vent-pipe outlets is again absorbed in the lower region by the suppression chamber. Thus, while an increase in heat reserve can be expected in the region below the vent-pipe outlets, the heat dissipation area for releasing heat to the outer peripheral pool is not increased; on the contrary, it rather decreases. Further, in this prior-art technique, no consideration is given to the continuity of the water circulation in the heat transfer pipes, which circulation is based on the difference in density due to the difference in temperature between the heat transfer pipes and the outer peripheral pool. The water in the heat transfer pipes and that in the outer peripheral pool are heated by the heat released from the suppression chamber and are reduced in density to be accumulated in the upper section of the pool. Since this accumulation takes place both in the heat transfer pipes and in the outer peripheral pool, and the outer peripheral pool is open to the atmospheric air, these two regions are eventually filled with water at the saturation temperature thereof (100.degree. C.), so that the requisite temperature difference cannot be secured between the two regions, resulting in the water circulation being stopped. With the prior-art technique for increasing heat dissipation presented in the Atomic Energy Society of Japan, the water in the suppression pool is circulated by the convection promoting plate installed in the suppression pool; due to this arrangement, that problem to which no consideration was given in the above prior-art technique can be solved, making it possible to utilize the region below the vent-pipe outlets and attain continuity in circulation. Since, however, only the containment-vessel wall is used as the heat transfer surface for releasing heat from the suppression chamber to the outer peripheral pool, the transfer area can only be enlarged in proportion to enlargement of the high-temperature region of the suppression pool, which means the suppression pool has to be enlarged if a further increase in heat dissipation is desired. That would entail an increase in the size of the reactor containment vessel. In the prior-art technique described in JP.A.2-227699, in which air cooling is effected, the rate of the heat transfer by the air circulation is lower than that of the convection heat transfer in the pool water, so that a large heat transfer area is needed to attain the requisite heat dissipation characteristic. Further, in this prior-art technique, no consideration is given to the above-mentioned necessity of raising the allowable temperature for the suppression pool. To attain a further improvement in heat dissipation characteristic in these prior-art reactor containment vessels so that they may be adapted to a nuclear plant of a larger output power, the heat dissipation area might be increased by enlarging the size of the reactor containment vessel. However, such an increase in the size of the reactor containment vessel would be a problem. In the reactor containment vessels described in JP.A.63-75594 (exclusive of FIG. 4) and JP.A.63-191096, which have been mentioned above, any rupture occurring, for example, in the main steam piping, will, as described above, cause the coolant in the reactor pressure vessel to enter the dry well as steam at high temperature and pressure, which steam will further flow through the vent pipes into the suppression-pool water to condense therein. In this process, part of the coolant in the reactor containment vessel will be drawn down in the dry well. It should be noted here that reactor containment facilities are generally equipped with emergency core cooling systems; when the pressure in the reactor pressure vessel has become lower than a predetermined value, the emergency core cooling system operates to cause water to be fed into the reactor pressure vessel for the purpose of submerging the core. This water further overflows from the rupture opening to be discharged into the dry well, with the result that the water level in the dry well is raised by the drawdown water and this overflow water. When the water level in the dry well has been raised up to the dry-well-side openings of the vent pipes, these hot waters flow into the suppression pool through the vent pipes. In the above prior-art techniques, however, the positions of the dry-well-side openings of the vent pipes are at high level, so that a large amount of water accumulates in the dry well at the time of an a loss-of-coolant accident as mentioned above; accordingly, the water level in the suppression pool only rises to a small degree, with the result that the contact area with the outer peripheral pool of the containment vessel cannot be greater than a fixed value. Further, since a large amount of hot water accumulates in the dry well, the temperature rise of the suppression-pool water is correspondingly dull and the difference in the temperature thereof and that of the outer-peripheral-pool water is small, with the result that the heat transfer from the suppression pool to the outer peripheral pool only occurs to a small degree. In other words, the cooling capacity of the containment vessel has to remain rather poor. By lowering the level of the dry-well-side openings of the vent pipes, the amount of water accumulating in the dry well is reduced and the amount of suppression-pool water is augmented, with the heat transfer to the outer pool of the containment vessel increasing. However, depending on the degree to which their level is lowered, it may happen that the dry-well-side openings of the vent pipes are immersed in water. In that case, it is difficult for the water level in the dry well to be smoothly lowered even if the pressure in the dry well is raised by the hot water accumulated therein (Pascal's principle), so that the pressure in the dry well rises to an excessive degree, resulting in the containment vessel being deteriorated in terms of safety. Thus, it is necessary to ascertain the degree to which the level of the dry-well-side openings of the vent pipes can be lowered without involving any problems. A prior-art technique for reducing the amount of water accumulated in the dry well is described in JP.A.63-229390, according to which a return line is provided, which extends through the wall in which the vent pipes are formed, i.e., the vent wall, and the opening on the dry well side of this return line is situated higher than the water surface of the suppression pool in the normal condition, whereby the suppression-pool water is prevented from flowing backwards to the dry well. Apart from this, shown in FIG. 4 of JP.A.63-75594, which has been mentioned above, is a structure which includes a core submerging hole allowing the dry well to communicate with the vent-pipes; this core submerging hole is provided in that portion of the vent wall which is on the dry well side, and at a height which is above the normal water level of the suppression pool and which allows the reactor core to be submerged. When, in these prior-art techniques, core coolant is drawn down into the dry well through any rupture opening, the water level in the dry well rises; when the water level has reached the height of the return line or that of the core submerging hole, the drawdown water flows into the suppression-pool water through the return line or the core submerging hole, thereby preventing the water level in the dry well from being raised. Further, since the drawdown water enters the suppression chamber, the water level of the suppression-pool water rises, thereby increasing the area of the heat transfer surface through which heat is transferred from the suppression chamber to the outer peripheral pool and improving the rate of heat dissipation from the containment vessel, which is required for a medium or long period of time after accident. In these prior-art techniques, however, the return line or the submerging hole is provided in the vent wall, so that the diameter of the return line or the submerging hole cannot be made large because of the necessity of retaining the requisite level of strength of the vent wall. Therefore, the amount of flow from the dry well to the suppression pool through the return line or the submerging hole is limited, so that, while the water amount in the dry well is increasing at high rate, it is impossible to completely prevent the water-level in the dry well from rising. Thus, the uppermost and hottest portion of the water in the dry well is not transferred to the suppression pool, so that, for a short period after the occurrence of an accident, the containment vessel suffers deterioration in its ability to transfer heat from the dry well to the suppression pool, resulting in the vessel being deteriorated in safety. Further, there are prior-art techniques in which the reactor core is cooled at the occurrence of a loss-of-coolant accident by supplying water into the core by a static means, as disclosed in "Simplicity; the key improved safety, performance and economics", Nuc. Eng. November 1989, and JP.A.63-229390 mentioned above. According to the prior-art technique described in Nuc. Eng. November 1989, the cooling of the reactor core for a short period after the occurrence of any loss-of-coolant accident is effected by means of a gravity-driven water pool in an emergency core cooling system, and the cooling of the reactor core for a long period after the occurrence of the same is achieved by returning the pool water in the suppression pool to the pressure vessel through an equalizing system. For this purpose, the equalizing system comprises an equalizing line which connects the suppression-pool water with the pressure vessel, a blasting valve provided in this equalizing line such as to remain closed during normal operation and as to be opened only at the time of an accident, and a check valve for preventing the coolant in the pressure vessel from flowing into the suppression pool. For a long period after the occurrence of an accident, the water in the containment vessel fills the lower dry well to the full by the gravity-driven water pool, and further fills dry well to the height of the inlets of the vent pipes (or the height of the return line leading to the suppression pool), with drawdown water flowing into the suppression-pool water to raise the water level thereof. As a result, the area of the heat transfer surface through which heat is transferred from the suppression chamber to the outer peripheral pool is augmented, thereby improving the rate of heat dissipation from the containment vessel as required for a medium or long period of time. In this case, it is necessary for the water in the containment vessel to fill the same up to the height of the inlets of the vent pipes (or the height of the return line leading to the suppression pool), with the result that a large amount of gravity-driven-pool water is required. In the prior-art technique described in JP.A.63-229390, the core cooling for a short period after the occurrence of a loss-of-coolant accident is effected by means of an accumulator water tank provided in the emergency core cooling system, and the core cooling for a long period after the occurrence of the accident is attained by the equalizing system connecting the suppression pool with the pressure vessel, as in the prior-art technique described in Nuc. Eng. November 1989. Also in this case, the water in the containment vessel for a long period in the containment vessel has to fill the dry well up to the height of the return line leading to the suppression pool, so that an accumulator water tank of a large capacity is required. Thus, in both of the prior-art techniques described in Nuc. Eng. November 1989 and JP.A.63-229390, it is necessary to previously set the water amount of the gravity-driven water pool or the accumulator water tank at a high level, with the result that the wall of the building structure supporting the same must be made thick. In addition, there is the problem that a more strict requirement is imposed on the structure in terms of earthquake-proof property. SUMMARY OF THE INVENTION It is a first object of this invention to provide a reactor containment facility in which an improvement is attained in terms of the heat dissipation characteristic of the reactor containment vessel for a long period of time after the occurrence of a loss-of-coolant accident while avoiding, as far as possible, augmentation in the size of the reactor containment vessel, so as to be suitable for use in a nuclear plant of a larger output power. A second object of this invention is to provide a reactor containment facility which realizes an improvement in the heat dissipation characteristic of the reactor containment vessel by increasing the allowable temperature for the suppression chamber. A third object of this invention is to provide a reactor containment facility in which an improvement is attained in terms of safety for a short period of time after the occurrence of a loss-of-coolant accident as well as in terms of the heat dissipation characteristic of the reactor containment vessel. A fourth object of this invention is to provide a reactor containment facility in which a reduction can be attained in the volume of the water source for the emergency core cooling system as well as an improvement in the heat dissipation characteristic of the reactor containment vessel. To achieve the above first and second objects, there is provided, according to a first aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a containment vessel housing the dry well; a suppression chamber holding a suppression-pool water and forming above it a first wet well; and passage means allowing the dry well to communicate with the pool water; wherein the facility further comprises: (a) means for defining a second wet well communicating with the first wet well; and (b) cooling means for keeping the second wet well at a temperature lower than that of the first wet well at the time of a loss-of-coolant accident. The reactor containment facility in accordance with the first aspect of this invention operates as follows: At the time of a loss-of-coolant accident, the high-temperature/pressure steam leaked into the dry well is transferred in a pressurized condition to the pool water in the suppression chamber along with the non-condensing gas in the dry well, and the steam is condensed in the pool water, with the noncondensing gas accumulating in the first wet well. The pool water is vaporized by the heat transferred thereto as a result of the condensation of the steam, the first wet well being filled with a mixture fluid of the steam and the noncondensing gas. The second wet well is at a relatively low temperature, so that when the mixture fluid is introduced into the second wet well from the first wet well, the steam in the mixture fluid is condensed into liquid to cause a reduction in pressure, with the second wet well becoming a noncondensing-gas region having practically no steam. The first wet well, in contrast, is brought to a condition in which it is substantially steam only that exists therein. Thus, when considering the pressure-proof property of the containment vessel, it is only necessary to take into account the vapor pressure in the first wet well, which is at a relatively high pressure level. Therefore, it is possible to raise the allowable temperature for the pool water to a saturated-steam temperature corresponding to the withstanding pressure of the containment vessel, which means the difference in temperature between the suppression-pool water and the portion outside thereof can be made so much the larger, thus attaining an improvement in heat dissipation capacity. By thus improving the heat dissipation capacity, the pressure-rise suppression effect of the reactor containment vessel is improved, thereby making it possible to provide a reactor containment vessel suitable for use in a nuclear plant of a larger output power. The second wet well may be provided separately from the conventional wet well, and the suppression chamber may be divided into a first chamber containing the pool water and a second chamber, the second wet well being defined by said second chamber. In the latter case, the second wet well is formed in the suppression chamber, so that the reactor containment facility of the present invention can be realized in a compact structure. The reactor containment facility preferably further comprises: (c) a steel wall which is in contact with the suppression-pool water and which surrounds at least the pool water so as to form the above-mentioned containment vessel; and (d) an outer peripheral pool containing a cooling water in contact with the outer peripheral surface of the steel wall. With this construction, the pool water of the suppression pool is in contact with the outer-peripheral-pool water through the intermediation of a wall that is made of steel, which is a good conductor of heat, so that a satisfactory level of heat transfer efficiency can be obtained, thus attaining a further improvement in heat dissipation capacity. To achieve the above first and second objects, there is provided, according to a second aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a containment vessel housing the dry well; a suppression chamber holding a suppression-pool water and forming above it a first wet well; and a passage means allowing the dry well to communicate with the pool water; wherein the facility further comprises: (a) means for defining a second wet well communicating with the first wet well; and (b) means which separates a mixture fluid consisting of the noncondensing gas in the suppression chamber and the steam from the pool water into the noncondensing gas and the steam and which causes the steam after the separation to remain in the first wet well and the noncondensing gas to be collected in the second wet well. The operation of the reactor containment facility in accordance with the second aspect of this invention is substantially the same as that of the reactor containment facility in accordance with the first aspect thereof. Also in this case, the reactor containment facility preferably further comprises: (c) a steel wall which is in contact with the suppression-pool water and which surrounds at least the pool water so as to form the above-mentioned containment vessel; and (d) cooling means for cooling the outer peripheral surface of the steel wall. Further, to achieve the above first and second object of this invention, there is provided, according to a third aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the suppression chamber; and an outer peripheral pool containing a cooling water in contact with the outer peripheral surface of the steel wall; wherein the facility further comprises: (a) dividing means for dividing the wet well of the suppression chamber into a first space which is in contact with the water surface of the pool water and a second space which is not in contact therewith; (b) first passage means which allows the first space to communicate with the second space and which has an area smaller than that of the dividing means; and (c) cooling means for keeping the second space at a temperature lower than that of the first space. The reactor containment facility in accordance with the third aspect of this invention operates as follows: At the time of a loss-of-coolant accident, there exists in the first space a mixture fluid consisting of the steam generated from the pool water and noncondensing gas; in the second space, the steam is condensed and the noncondensing gas accumulates; as a result, the allowable temperature of the suppression chamber is raised, as stated above, thereby improving the heat dissipating characteristic of the reactor containment vessel. Here, the first and second spaces communicate with each other through a narrow passage means, so that the intrusion of the mixture fluid from the first into the second space takes place gradually, whereby the condensation of the steam in the mixture fluid can take place steadily in the second space, leaving no steam to remain uncondensed for a long time. Thus, fractional collection of noncondensing gas and steam can be effected reliably. Further, since the suppression-pool water is water-cooled by the outer peripheral pool, the suppression effect of the reactor containment vessel is improved. Preferably, the above reactor containment facility further comprises: (d) second passage means allowing the lower section of the second space to communicate with the suppression-pool water. Due to this construction, the water condensed in the second space is returned to the suppression pool through the second passage means, thereby further enhancing the degree of repletion of the noncondensing gas in the second space. Further, the above-mentioned steel wall preferably further surrounds the first and second spaces, the above-mentioned cooling means including an air passage formed outside the steel wall. The cooling means may include a recess region formed by extending downwards the outer peripheral section of the second space to be in thermal contact with the cooling water of the outer peripheral pool. The reactor containment facility preferably further comprises: (e) at least one convection promoting pipe which is arranged in the outer peripheral pool and which has at least one upper opening situated below the water surface of the suppression-pool water at a position above the outlets of the vent pipes and at least one lower opening situated in the pool water at a position below the outlets of the vent pipes, with the upper and lower openings communicating with each other to allow the pool water to pass therethrough. With this construction, a further improvement in heat dissipation characteristic can be attained due to the action of the convection promoting pipes described below. Further, the reactor containment facility may further comprise: (f) a convection promoting plate which is arranged in the suppression-pool water along the stee wall, the upper end of the plate being positioned higher than the outlets of the vent pipes, the lower end of the plate being positioned lower than the outlets of the vent pipes, with the difference in height between the upper end and the outlets of the vent pipes being larger than the difference in height between the outlets of the vent pipes and the lower end. With this construction, the convection promoting plate helps to enlarge the convection region of the pool water to enhance the heat dissipation through the steel wall, thereby attaining a further improvement in terms of heat dissipation characteristic. Further, to achieve the above first and second objects, there is provided, according to a fourth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a containment vessel housing the dry well; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; and passage means allowing the dry well to communicate with the pool water; wherein the facility further comprises: (a) means arranged on the water surface of the pool water of the suppression chamber for serving to restrain the evaporation of the pool water. The operation of the reactor containment facility in accordance with the fourth aspect of this invention is as follows: At the time of a loss-of-coolant accident, some of the steam at high temperature and pressure is leaked into the dry well and transferred in a pressurized condition to the pool water of the suppression chamber along with the noncondensing gas in the dry well; the steam is condensed, and the noncondensing gas accumulates in the wet well. As a result of this condensation, the temperature of the suppression-pool water is raised; since, however, the evaporation is restrained by the evaporation restraining means, the evaporation of the pool water, which, in the prior art, would start at the saturation temperature corresponding to the vapor partial pressure in the wet well, starts at the saturation temperature corresponding to the total pressure in the wet well. As a result, the temperature of the suppression-pool water can be kept at a higher level under the same wet-well pressure, so that the difference in temperature between the suppression-pool water and the outside of the reactor containment vessel is augmented, thereby attaining an improvement in heat dissipation effect. The reactor containment facility preferably further comprises: (b) a steel wall in contact with the suppression-pool water and surrounding at least the pool water so as to form the above-mentioned containment vessel; and (c) cooling means for cooling the outer peripheral surface of the steel wall. Further, to achieve the above first and second objects, there is provided, according to a fifth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the suppression chamber; and an outer peripheral pool containing a cooling water in contact with the outer peripheral surface of the steel wall; wherein the facility further comprises: (a) a hydrophobic-material layer which is formed on the water surface of the suppression-pool water and which has a saturation vapor pressure and a density that are lower than those of the pool water. The operation of the reactor containment facility in accordance with the fifth aspect of this invention is as follows: When, at the time of a loss-of-coolant accident, the temperature of the suppression-pool water rises as a result of steam condensation, the evaporation of the pool water is restrained since the saturation vapor pressure of the hydrophobic-material layer floating on the pool-water surface is lower than that of water. That is, this hydrophobic-material layer functions as a means of restraining the evaporation of the pool water. Accordingly, the temperature of the suppression-pool water can be kept at a higher level, as stated above, thereby attaining an improvement in heat dissipation effect. Further, since the suppression-pool water is water-cooled by the outer peripheral pool, the suppression effect of the reactor containment vessel is improved. Further, to achieve the above first and second objects, there is provided, according to a sixth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a containment vessel housing the dry well; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; and passage means allowing the dry well to communicate with the pool water; wherein the facility further comprises: (a) circulation passage means which has an intake opening situated in the pool water at a position higher than the outlet of the passage means leading to the pool water and a discharge opening situated in the pool water at a position lower than the same, with at least a part of the circulation passage means being situated outside the suppression chamber. The reactor containment facility in accordance with the sixth aspect of this invention operates as follows: At the time of a loss-of-coolant accident, the steam at high temperature and pressure is leaked into the dry well and transferred in a pressurized state to the pool water through the passage means along with the noncondensing gas in the dry well, the steam being condensed and the noncondensing gas accumulating in the wet well. The pool water in that portion of the passage means which is higher than the above-mentioned outlet leading to the pool water is at a higher temperature as compared with the pool water in that portion of the passage means which is lower than that. That portion of the pool water which is at a relatively high temperature is taken up by the circulation passage means. Since the circulation passage means is situated outside, the pool water thus taken up is cooled to be increased in density, and descends of its own accord to be returned to the suppression-pool water through the discharge opening of the circulation passage means. This causes a circulation flow to be generated, by means of which the suppression-pool water is moved to promote heat dissipation. The above reactor containment facility preferably further comprises: (b) cooling means provided in that portion of the circulation passage means which is situated outside the suppression chamber. By cooling the circulation passage means by the cooling means, the heat dissipation capacity of the facility is further enhanced. Further, to achieve the above first and second objects, there is provided, according to a seventh aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a containment vessel housing the dry well; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; and passage means allowing the dry well to communicate with the pool water; wherein the facility further comprises: (a) circulation passage means at least a part of which is situated outside the suppression chamber for causing the pool water to be circulated from a position higher than the pool-water side outlet of the passage means to a position lower than the same. The operation of the reactor containment facility in accordance with the seventh aspect of this invention is substantially the same as that of the facility in accordance with the sixth aspect of this invention. Also in this case, the reactor containment facility preferably further comprises: (b) cooling means provided in that portion of the circulation passage means which is situated outside the suppression chamber. Further, to achieve the above first and second objects, there is provided, according to an eighth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the suppression chamber; and an outer peripheral pool containing a cooling water in contact with the outer peripheral surface of the steel wall; wherein the facility further comprises: (a) at least one convection promoting pipe which is arranged in the outer peripheral pool and which has at least one upper opening situated below the water surface of the suppression-pool water at a position above the outlets of the vent pipes and at least one lower opening situated in the pool water at a position below the outlets of the vent pipes, with the upper and lower openings communicating with each other to allow the pool water to pass therethrough. The operation of the reactor containment facility in accordance with the eighth aspect of this invention is substantially the same as that of the facility in accordance with the seventh aspect, except for the fact that the pressure suppression effect of the reactor containment vessel is further improved due to the water-cooling of the suppression-pool water by the outer peripheral pool. In the above containment facility, the difference in height between the upper opening mentioned above and the outlets of the vent pipes is larger than the difference in height between the outlets of the vent pipes and the lower opening mentioned above. Further, the above-mentioned convection promoting pipe preferably includes upper and lower header pipes respectively arranged at upper and lower positions in the outer peripheral pool and a plurality of heat transfer pipes allowing the upper and lower header pipes to communicate with each other. To achieve the above first and third objects, there is provided, according to a ninth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a first suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of first vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the first suppression chamber; an outer peripheral pool containing a cooling water in contact with the outer peripheral surface of the steel wall; and an emergency core cooling system adapted to cool the core by supplying a water into the pressure vessel at the time of a loss-of-coolant accident; wherein the height of the dry-well-side openings of the first vent pipes is so determined that when the water level in the dry well, in which water overflowing from the reactor pressure vessel accumulates at the time of a loss-of-coolant accident, has attained a core submerging level which allows submergence cooling of the core, the water in the dry well starts to flow into the first suppression chamber through the first vent pipes. The operation of the reactor containment facility in accordance with the ninth aspect of this invention is as follows: If an accident should occur in which some of the coolant in the reactor pressure vessel is lost due to a rupture in the piping, etc., the water in the emergency core cooling system, e.g., that in the accumulator tank, flows into the reactor pressure vessel and enters the dry well through the rupture opening, thereby raising the water level in the dry well. Since the pressure in the reactor containment vessel has been sufficiently reduced by the time the water level in the dry well reaches the rupture opening, the water level in the reactor pressure vessel rises from the time onwards at which the water level in the dry well has exceeded the rupture opening as does the water level in the dry well, and attains a level equal to the submergence level of the dry well. Here, the core submerging level of the dry well, which partly depends on the structure of the reactor containment vessel, is set at a value which is obtained by adding a margin height, e.g., of approx. 50 cm, to the height of the upper end of the core in the reactor pressure vessel, taking some fluctuation in water level into account. Thus, it is also possible to cope sufficiently with the evaporation of the cooling water in the reactor pressure vessel due to the core decay heat after the submergence. When the water level in the dry well has reached the core submerging level, the water in the dry well flows, starting with the uppermost hot water portion, which is the hottest water portion in the dry well through the vent pipes to the suppression pool, causing the water level and temperature of the suppression-pool water to rise. When the water in the accumulator tank, etc. has been used up, the water level of the suppression-pool water ceases to rise. As a result, the water level in the suppression pool rises higher than in the normal state and the area of the heat transfer surface through which heat is transferred to the outer peripheral pool is enlarged, thereby attaining an improvement in terms of heat dissipation for a long period of time after accident. Further, when the water level in the dry well has reached the core submerging level, the uppermost hot water portion in the dry well immediately starts to flow through the vent pipes into the suppression pool, so that heat transfer to the suppression chamber is effected in an efficient manner, thereby attaining an improvement in terms of safety for a short period after accident. Further, since the temperature of the suppression-pool water is raised to a maximum, the difference in temperature between the suppression pool and the outer peripheral pool of the reactor containment vessel is augmented, thereby making it also possible to increase the quantity of heat that is transferred. In the above reactor containment facility, the amount of coolant stored in the water source of the emergency core cooling system is preferably set such as to be substantially equal to the sum of the amount of coolant needed for raising the water level in the dry well up to the core submerging level and the amount of coolant required for making the water level of the suppression-pool water equal to the core submerging level. Due to this arrangement, the water level in the pressure suppression pool can be raised up to the core submerging level for the dry well, thereby making it possible to enlarge to a maximum the heat transfer area between the suppression pool and the outer peripheral pool of the containment vessel. Further, a structure for reducing the amount of coolant when the water level in the dry well has been raised to the core submerging level is preferably provided in that portion of the space in the dry well which is below the core submerging level. This helps to reduce the time it takes for the water level in the dry well to reach the core submerging level, thereby attaining an improvement in terms of safety. Moreover, since the amount of coolant needed for the submergence may be small, it is possible to reduce the capacity of the accumulator tank, etc. for supplying water to the core. Further, to achieve the above first and third objects, there is provided, according to a tenth aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a first suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of first vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the first suppression chamber; and an outer peripheral pool containing cooling water in contact with the outer peripheral surface of the steel wall; wherein the facility further comprises: (a) a second suppression chamber situated above the first suppression chamber and including a suppression pool and a wet well, the suppression pool communicating with the dry well through a plurality of second vent pipes; and (b) a line equipped with a valve and connecting the second suppression chamber with the reactor pressure vessel to provide an emergency core cooling system. The operation of the reactor containment facility in accordance with the tenth aspect of this invention is as follows: If an accident should occur which causes some of the reactor cooling water in the reactor pressure vessel to be discharged into the dry well due to a rupture in the piping, etc., the high-temperature water discharged into the dry well accumulates in the lower section of the dry well; the steam, however, flows through the first and second (the upper and lower) vent pipes and condenses in the suppression pools, so that there is no excessive rise in the pressure in the containment vessel. The valve provided in the line leading from the pool water of the second suppression chamber (the upper-suppression-pool water) to the reactor pressure vessel is opened when the water level in the reactor pressure vessel has been lowered to reduce the drawdown from the rupture opening, and the pressure in the reactor pressure vessel has decreased, or when the pressure in the reactor pressure vessel has been lowered to a sufficient degree by means of a safety relief valve. By thus opening the above valve provided in the line, the water in the upper suppression pool is fed into the reactor pressure vessel to cool the core. The water thus fed flows out through the rupture opening into the dry well, causing the water level in the dry well to rise. When the dry-well water level has reached the dry-well-side openings of the first vent pipes, water flows into the pool water of the first suppression chamber (the lower suppression pool), causing the water level in the lower suppression pool to rise. Due to this arrangement, the submergence cooling of the reactor core can be performed if there is no drive source such as a pump, and, since the water level in the lower suppression pool rises to a large degree, a large area can be secured for the heat transfer to the outer peripheral pool of the containment vessel. That is, an improvement is attained in terms of heat dissipation for a long period of time after accident. Further, by arranging suppression pools at upper and lower positions, the number of vent pipes can be augmented, so that the overshoot of the pressure in the dry well due to the vent-pipe resistance immediately after accident can be reduced, thereby achieving an improvement in terms of safety. Further, by dividing the requisite coolant amount of the suppression pool into upper and lower portions, the water depth in the suppression pools can be set at the same level as in the prior art, so that it is possible to reduce the size (the area or the outer diameter) of the upper and lower suppression pools, that is, the diameter of the containment vessel. In the above reactor containment facility, the height of the dry-well-side openings of the first vent pipes is preferably set at a level substantially equal to a core submerging level which is that water-level in the dry well at which submergence cooling of the core can be effected with the water in the dry well, which has overflowed from the reactor pressure vessel and accumulated in the dry well at the time of a loss-of-coolant accident. As in the case of the facility in accordance with the ninth aspect, this arrangement is advantageous in that when the water level in the dry well has reached the core submerging level, the water in the dry well flows, starting with the uppermost hot water portion, which is the hottest water portion in the dry well, to the suppression pool through the vent pipes, and the water level and temperature of the suppression-pool water start to rise, whereby heat transfer to the suppression chamber is effected in an efficient manner, thus attaining a further improvement in terms of safety for a short period of time after accident. Further, the amount of coolant of the second suppression chamber is preferably set such as to be substantially equal to the sum of the amount of coolant needed for raising the water level in the dry well up to the core submerging level and the amount of coolant required for making the water level of the suppression-pool water equal to the core submerging level. Due to this arrangement, the water level in the lower suppression pool rises to the level of the dry-well-side openings of the vent pipes, so that the heat transfer area between the suppression pool and the outer peripheral pool of the containment vessel can be enlarged to a maximum. To achieve the above first and fourth objects, there is provided, according to an eleventh aspect of this invention, a reactor containment facility comprising: a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a suppression chamber holding a suppression-pool water and forming, in the space above the same, a wet well; a plurality of vent pipes allowing the dry well to communicate with the pool water; a steel wall which is in contact with the pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the suppression chamber; an outer peripheral pool containing cooling water in contact with the outer peripheral surface of the steel wall; and an emergency core cooling system adapted to cool the core by supplying water into the pressure vessel at the time of a loss-of-coolant accident; wherein the facility further comprises: (a) equalizing means which, for a long period of time after a loss-of-coolant accident, cools the core by supplying water into the pressure vessel, utilizing the suppression-pool water and the drawdown water accumulated in the dry well as a water source. The reactor containment facility in accordance with the eleventh aspect of this invention operates as follows: Due to the provision of an equalizing means which, for a long period of time after a loss-of-coolant accident, supplies water into the pressure vessel by utilizing the suppression-pool water and the drawdown water in the lower section of the dry well as the water source, the drawdown water in the lower dry well can be directly utilized as a new water source,. so that there is no need to fill the dry well with drawdown water up to the height of the vent pipes and return it to the suppression pool for the purpose of using the same. Therefore, it is only necessary for the water source of the emergency core cooling system to have a capacity large enough to fill the lower dry well up to the core submerging level, thus making it possible to reduce the capacity of the water source. By the "drawdown water" is meant that portion of the cooling water in the pressure vessel which has outflowed through the rupture opening and that portion of the cooling water which has been leaked out through the rupture opening after being fed into the pressure vessel from the emergency core cooling system. Further, since it is also possible to transfer the decay heat from the suppression pool to the outer peripheral pool through the wall of the containment vessel, the cooling of the core and the containment vessel can be effected by a static means for a long period of time after the occurrence of an accident. In the above reactor containment facility, the opening in the suppression-pool water of the equalizing means is preferably at a height near the water surface of the pool water. Due to this arrangement, the water level in the suppression pool can be maintained at a high level when it is so set, so that the area of the heat transfer surface through which heat is transferred to the outer peripheral pool can be enlarged, thereby attaining an improvement in terms of heat dissipation. Further, the above-mentioned equalizing means preferably includes: a first equalizing line connecting the suppression-pool water with the pressure vessel; a second equalizing line branching off from the first equalizing line and opening at a position below the dry well; an isolation valve provided between the point at which the first equalizing line is connected with the pressure vessel and the branching point at which the second equalizing line branches off; and check valves respectively provided in the first and second equalizing lines, said check valves in the first equalizing line being positioned between the branching point and the point at which the first equalizing line is connected with the suppression-pool water and in the second equalizing line. In this case, the opening in the suppression-pool water of the first equalizing line is preferably at a level near the water surface of the pool water. The above reactor containment facility preferably further comprises: (b) first detection means for detecting the pressure in the pressure vessel; (c) second detection means for detecting the water level in the pressure vessel; (d) third detection means for detecting the pressure in the dry well; (e) a pressure reducing valve connected with the pressure vessel and adapted to allow the steam in the pressure vessel to escape to the dry well; and (f) control means which is adapted to open the pressure reducing valve in response to a low-water-level signal indicative of low water level in the pressure vessel and supplied from the second detection means and to a high-pressure signal indicative of high pressure in the dry well and supplied from the third detection means so as to allow the steam in the pressure vessel to escape therefrom, and which, afterwards, opens the isolation valve to operate the equalizing means, in response to a low-pressure signal indicative of low pressure in the pressure vessel. With this construction, the isolation valve of the equalizing means is opened after the pressure reducing valve has been automatically opened in the process during which the pressure in the pressure vessel decreases after the occurrence of an accident. When the isolation valve of the equalizing means has been opened, a reduction to a sufficient degree in the pressure in the pressure vessel after a long time after the occurrence of the accident will cause the pool water in the suppression pool and the drawdown water in the dry well to flow into the pressure vessel due to water head. Since check valves are provided in the first and second equalizing lines of the equalizing means, there is no risk of the water in the pressure vessel flowing backwards to the dry well or the suppression pool, and none of the pool water in the suppression pool will flow into the dry well. The above-mentioned isolation valve may comprise a blasting valve or an electrically operated valve. Further, the first and second equalizing lines are preferably respectively equipped with each two of isolation valves and check valves as mentioned above that are arranged in parallel; thus, if one of the systems becomes out of order, the equalizing means can be reliably operated by the other one. |
claims | 1. A single fluid molten salt nuclear reactor comprising:a vessel having a central region and a vessel wall, a vessel height and a vessel width;a support structure;a neutron moderator secured to the support structure and located in the central region of the vessel, the neutron moderator having a neutron moderator height and a neutron moderator width, the vessel height being greater than the neutron moderator height by a factor comprised between two and four, the vessel width being greater than the neutron moderator width by a factor comprised between two and four such that an under-moderated zone is defined between the neutron moderator and the vessel wall, the neutron moderator having at least one through hole defined therein that is in fluid communication with the under-moderated zone; anda pump to circulate a molten salt in the vessel, the support structure, the neutron moderator, and the pump being arranged to circulate the molten salt through the at least one through hole of the neutron moderator and the under-moderated zone between the neutron moderator and the vessel wall;wherein a space between the neutron moderator and the vessel wall is free of any neutron reflector. 2. The nuclear reactor of claim 1 wherein the support structure is also a guide structure to guide the molten salt therethrough, the support structure, the neutron moderator, and the pump being arranged to circulate the molten salt first through the support structure, then through the at least one through hole of the neutron moderator, and subsequently between the neutron moderator and the vessel wall. 3. The nuclear reactor of claim 1 wherein the support structure is also a guide structure to guide the molten salt therethrough, the support structure, the neutron moderator, and the pump being arranged to circulate the molten salt first between the neutron moderator and the vessel wall, then through the at least one through hole of the neutron moderator, and subsequently through the guide structure. 4. The nuclear reactor of claim 1 wherein the neutron moderator is a cylinder-shaped neutron moderator, the at least one through hole being parallel to a height of the cylinder-shaped neutron moderator. 5. The nuclear reactor of claim 1 wherein the at least one through hole is perpendicular to the neutron moderator width. 6. The nuclear reactor of claim 1 wherein the vessel has a vessel height and the neutron moderator has a neutron moderator height, the at least one through hole being parallel to the neutron moderator height. 7. A single fluid molten salt nuclear reactor comprising:a vessel having a central region and a vessel wall, a vessel height and a vessel width;two opposite walls disposed at opposite ends of the vessel;a support structure;a neutron moderator secured to the support structure and located in the central region of the vessel, the neutron moderator having a neutron moderator height and a neutron moderator width, the vessel height being greater than the neutron moderator height by a factor comprised between two and four, the vessel width being greater than the neutron moderator width by a factor comprised between two and four such that an under-moderated zone is defined between the neutron moderator and the vessel wall, the neutron moderator having at least one through hole defined therein that is in fluid communication with the under-moderated zone;a molten salt inlet formed on one of the two opposite walls;a molten outlet formed on the other of the two opposite walls; anda pump operationally connected to the molten salt inlet and to the molten salt outlet, the pump to circulate a molten salt in the vessel, through the at least one through hole of the neutron moderator and the under-moderated zone between the neutron moderator and the vessel wall;wherein a space between the neutron moderator and the vessel wall is free of any neutron reflector. 8. The nuclear reactor of claim 1 wherein the neutron moderator includes at least one of graphite and of clad beryllium compound. 9. The nuclear reactor of claim 1 wherein the neutron moderator is one of graphite, a clad beryllium compound, and a clad graphite powder. 10. The nuclear reactor of claim 7 wherein the neutron moderator includes at least one of graphite and of clad beryllium compound. 11. The nuclear reactor of claim 7 wherein the neutron moderator is one of graphite, a clad beryllium compound, and a clad graphite powder. 12. A single fluid molten salt nuclear reactor comprising:a vessel having a central region and a vessel wall, the vessel wall being free of any graphite neutron reflector, the vessel having a vessel height and a vessel width;a neutron moderator positioned a central region of the vessel, the neutron moderator having a neutron moderator height and a neutron moderator width, the vessel height being greater than the neutron moderator height by a factor comprised between two and four, the vessel width being greater than the neutron moderator width by a factor comprised between two and four such that an under-moderated zone is defined between the neutron moderator and the vessel wall, the neutron moderator having at least one through hole defined therein that is in fluid communication with the under-moderated zone; anda pump to circulate a molten salt in the vessel, the neutron moderator and the pump being arranged to circulate the molten salt through the at least one through hole of the neutron moderator and the under-moderated zone between the neutron moderator and the vessel wall such that the molten salt in the under-moderated zone reduces a neutron flux at the vessel wall to reduce damage to the vessel wall;wherein a space between the neutron moderator and the vessel wall is free of any neutron reflector. 13. The nuclear reactor of claim 12 wherein the neutron moderator:is a graphite neutron moderator,has a width comprised between one meter and two meters, andhas a height that matches the width of the neutron moderator. 14. The nuclear reactor of claim 12 further comprising a support structure that positions the neutron moderator at the central region of the vessel, the support structure having a conduit portion, the support structure, the neutron moderator, and the pump being configured to circulate the molten salt first through the conduit portion of the support structure, then through the at least one through hole of the neutron moderator, and subsequently between the neutron moderator and the vessel wall. 15. The nuclear reactor of claim 12 wherein the support structure is also a guide structure to guide the molten salt therethrough, the support structure, the neutron moderator, and the pump being arranged to circulate the molten salt first between the neutron moderator and the vessel wall, then through the at least one through hole of the neutron moderator, and subsequently through the guide structure. 16. The nuclear reactor of claim 12 wherein the neutron moderator is a cylinder-shaped neutron moderator, the at least one through hole being parallel to a height of the cylinder-shaped neutron moderator. 17. The nuclear reactor of claim 12 wherein the neutron moderator includes at least one of graphite and of clad beryllium compound. 18. The nuclear reactor of claim 12 wherein the neutron moderator is one of graphite, a clad beryllium compound, and a clad graphite powder. |
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abstract | In a nuclear reactor, a core barrel (46) is disposed in a reactor vessel (41) having an inlet nozzle (44) and an outlet nozzle (45), a core (53) is disposed in the core barrel (46), a lower plenum (58) is partitioned by the reactor vessel (41) and a bottom portion of the core barrel (46), and a downcomer portion (59) is partitioned by the reactor vessel (41) and a side wall of the core barrel (46). The lower plenum (58) includes a straightening member (61) formed of an upper ring (65) and a lower ring (69) in a ring shape, and a plurality of spokes (64 and 68) radially arranged inside the rings (65 and 69), respectively. Heat exchange efficiency is enhanced by uniformly supplying coolant introduced into a pressure vessel to the core from the lower plenum in a radial direction and a circumferential direction. |
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description | 1. Field of the Invention The present invention concerns a method for automatically adjusting a radiation-gating diaphragm (having a number of adjustable diaphragm elements) for a subsequent x-ray exposure of an examination subject, wherein the individual diaphragm elements are respectively positioned such that they—considered in a projection lying in a detector plane—contact the contours of the acquisition subject or are arranged at a small distance therefrom. The invention also concerns an x-ray system with an x-ray source, an x-ray detector, a diaphragm (arranged in an x-ray beam path between the x-ray source and the x-ray detector) with a number of automatically adjustable diaphragm elements, and a diaphragm control device in order to position the individual diaphragm elements. 2. Description of the Prior Art A diaphragm of the above type, known as a “depth diaphragm” or a “primary beam diaphragm” normally is located in the beam path between the x-ray source and the acquisition subject. It primarily has the object to allow only the acquisition subject to be irradiated, and not the surrounding areas. For example, in exposures of specific body parts or organs of a person, only tissue is irradiated that is necessary for the diagnosis or the planned intervention, such that the radiation dose for the subject is reduced. Moreover, given exposures in which, for example, the subject is a body part of a person, x-ray radiation is prevented from arriving unattenuated directly from the x-ray source (past the subject) to the detector. Such “direct radiation” can lead to image artifacts depending on the design of the detector. Thus, for example, due to scattering or due to transverse re-direction of the radiation in the detector glass, a lateral spatial expansion of the signal in the subject region can occur. This phenomenon can lead in an image intensifier to a phenomenon known as “low frequency drop”. Moreover, such direct radiation can lead to the individual structural elements of a planar image detector, assembled from a number of detector parts, respectively becoming visible at the Impact locations and interfering in the image. By the use of the depth diaphragm that covers (blocks) the irrelevant regions, so the beam precision is increased, and the image quality is improved. Such a diaphragm can either completely gate the x-ray radiation or can be semi-transparent and attenuate the radiation. The first type of diaphragm has the advantage that no x-ray radiation whatsoever arrives in the irrelevant region. By contrast, the second type of diaphragm has the advantage that, although the regions located near the actual exposure subject will appear lighter in the image, to the same extent that the visibility is increased in the region of interest, but high-contrast objects (such as, for example, operating instruments) that are laterally introduced into the examination subject) are still visible. In both versions, an optimally good adaptation of the diaphragm to the respective examination subject is important for the proper functioning of such a diaphragm, so that the examination subject is not covered by the diaphragm plates, and the surrounding regions of no interest are covered to the extent possible. In most conventional x-ray examination apparatuses, it is only possible to effect the adjustment of the diaphragm by hand, for example with the aid of a light-beam localizer. Moreover, there are x-ray systems in which it is possible to implement an automatic preadjustment using an organ program downloaded into a system control that before any manual adjustment, an approximate diaphragm adjustment to the region of interest is made. A disadvantage is that the actual position of the examination subject can vary significantly due to the positioning (for example of a patient) and variation in the size of a patient or of the respective examination subject. An ideal adjustment thus is not possible with these methods. In contrast to this, an exact adjustment of the depth diaphragm by fine adjustment by hand requires a relatively long time, which is counter to achieving an optimal workflow with short wait times for the patients. German 35 00 812 describes an x-ray irradiation apparatus with a diaphragm of the above-described type, which has a number of diaphragm elements in the form of plates or lamellae that are positioned such that they abut the contours of the examination subject—viewed as a projection in the detector plane—at least at one point, meaning that the diaphragm elements projected from the x-ray source onto the detector plane abut the contours of the examination subject likewise projected from the x-ray source onto the detector plane. For this purpose, the apparatus has a placement device for the individual plates. The detector an x-ray image intensifier with a television camera connected thereto to generate video signals. Connected to the television camera is a special evaluation circuit which is designed such that specific image regions in the video signal are each associated with specific plates or lamellae. At the beginning of an exposure of an examination subject, the diaphragm is completely open. With the control signals acquired from the video signal, the individual plates are then controlled by the evaluation circuit such that they move toward one another and thus slowly close the diaphragm. Each individual plate is stopped as to its closing motion when a specific preselected brightness level is undershot in the portion of the video signal associated with the corresponding plate. This technique consequently requires that the subject be irradiated for a certain amount of time during the adjustment of the diaphragm. Moreover, the use of the technique is limited to x-ray detectors with a video camera and with a special evaluation circuit for the video signals. An object of the present invention is to provide a method for automatic adjustment of a diaphragm and a corresponding x-ray system with such a diaphragm which enable an optimally simple, fast and good adjustment of the diaphragm before an x-ray acquisition. The object is achieved in accordance with the invention by a method and apparatus wherein, to position the individual diaphragm elements, a subject localization exposure is initially generated with low dosage with an open diaphragm. This subject localization exposure is analyzed to determine a contour of the exposure subject and, using the determined contours, the positions of the diaphragm elements are then calculated and the diaphragm elements are moved into the calculated positions so as to substantially abut the contour projected into the detector plane. (As used herein, “substantially abut” encompasses precise abutment with the contour projected into the detector plane, as well as a position a short distance away from precise abutment.) The subject localization exposure is implemented in an optimally short timeframe before the actual exposure, which preferably is not longer than the time necessary for a complete calculation and adjustment of the positions of the diaphragm elements. The dose thus can be very significantly less than in the actual exposure, for example only a tenth or a hundredth of the “normal” dose. To implement this method, in addition to the previously cited components, the inventive x-ray system has an x-ray system control that causes the subject localization exposure to be generated before an x-ray exposure with a low dose and with an open diaphragm; an image analysis device that analyzes the subject localization exposure to determine the contours of the exposure subject; and a position calculation device that, using the determined contours, calculates the positions of the diaphragm elements and conveys signals representing the calculated positions to the diaphragm control device for positioning the diaphragm elements. The invention has the advantage that a single short x-ray exposure (called a “pre-shot” below) with a very low dose is sufficient to determine the diaphragm position. This means that the additional dose exposure for the patient for the adjustment of the diaphragm positions is low. Moreover, in principle this method can be used in every type of x-ray apparatus that has a diaphragm control device for automatic positioning of the individual diaphragm elements. In particular an existing x-ray system control can be retrofitted without difficulty by reprogramming, for example with a corresponding software module. The image analysis device and the position calculation units likewise can be implemented in the form of suitable software modules in a central processor of the x-ray apparatus, for example of the x-ray system control itself or an image processing device that is already present. An existing x-ray apparatus thus can be inventively retrofitted at any time. In a preferred exemplary embodiment, for the generation of the subject localization exposure a number of adjacent image pixels are combined in groups to form a common image point. The resolution is reduced by the combinations (for example by a common readout) of individual pixels into groups of, for example, 2×2, 3×3 or 10×10 pixels, and thus the size of the image matrix is reduced. The calculation time is thereby reduced and the signal-to-noise ratio in the subject localization exposure, acquired with only a low dose is improved. Furthermore, the subject localization exposure can be added pixel-by-pixel to a subsequently obtained x-ray exposure. This means that the pre-shot and the actual exposure are added by calculation technologies, such that the dose used for the pre-shot is also completely utilized for generating the diagnostic image. Due to the very short time span between the pre-shot and the actual exposure, possible image artifacts are largely reduced and are therefore negligible. In the analysis of subject localization exposure, it is advisable to use known techniques in the image processing of x-ray images. One such method is direct ray detection, which is already used today in many cases for automatic windowing in the framework of the image processing. The subject localization exposure can be converted by means of the direct ray detection method into a representation in which the direct radiation region in which the x-ray radiation directly strikes unattenuated on the detector, is shown with a specific value, for example with 0, and the subject region is itself coded with another value, for example with 1. The result is then a binary image which can be very simply processed. There are a number of possibilities for precise calculation of the optimal positions of the diaphragm elements using the subject localization exposure. In a preferred version, the position of each diaphragm elements is calculated using the following position data: the coordinates of at least one point on the contour of the exposure subject in the subject localization exposure (that corresponds to the contour of the examination subject projected from the x-ray source on the detector plane); the position of the detector plane in which the image is acquired, relative to a primary x-ray beam direction (meaning the position along the direct connecting line between the x-ray source and the x-ray detector); the position of the diaphragm plane in which the diaphragm elements are adjustably arranged, relative to the primary x-ray beam direction. In most cases, the diaphragm plane and the detector plane are at right angles to the primary x-ray beam direction. The specification of a coordinate, for example for the distance of the diaphragm plane and detector plane relative to an x-ray source, or to a focal spot of the x-ray source, is sufficient to completely specify the positions of the detector plane and the diaphragm plane. When the detector plane and/or the diaphragm plane is slanted relative to the primary x-ray beam direction, the position must be specified by the specification of further coordinates, for example the coordinates of three points on the plane or specific angle specifications. Insofar as the distances of the diaphragm and the detector from the x-ray source remain the same, the coordinates of these positions are fixed anyway and no longer need to be-actively determined or calculated for the diagnostic exposure. To calculate the desired position of a diaphragm element, the coordinates of such a point which—considered in a projection in the detector plane—form an outermost point of the contour in the direction of the appertaining diaphragm element are preferably used on the contour of the exposure subject in the subject localization exposure. This means the points on the contour are precisely considered that first abut the diaphragm elements or would first be covered by these diaphragm elements given a movement of the diaphragm elements in a closing direction (considered in the projection on the detector plane). By suitable selection of a coordinate system in which the position data are determined and the calculations implemented, the necessary times for the determination of the positions of the diaphragm elements can be optimized. When the detector has a detector surface with detector elements in a matrix (meaning when it is, for example, a solid state detector with an active readout matrix) and the detector surface is situated perpendicularly to the primary x-ray beam direction, is appropriate to a coordinate system having an origin at the focal spot of the x-ray source and having coordinate axes in the primary x-ray beam direction (the z-axis in the following) and parallel to the rows and columns of the detector surface (x- and y-axes). The coordinates of a point on the contour of the exposure subject correspond in this coordinate system to the row and column numbers of the respective image pixel, meaning of the appertaining matrix element. In such a coordinate system, the coordinates of the boundary position (lying in the closing direction) of a diaphragm element within the diaphragm plane can be determined in a very simple manner by means of a ray set calculation. For example, the coordinates of the point on the contour of the exposure subject at which the appertaining diaphragm element (considered in the projection lying in the detector plane) would first contact the contour of the exposure subject given an adjustment in the closing direction, can be derived directly from the subject localization exposure. These coordinates then must only be multiplied with the quotients from the z-coordinate of the position of the diaphragm plane and the z-coordinate of the position of the detector plane in order to obtain the coordinates of the desired point in the image plane over which the appertaining diaphragm element may not be moved in the closing direction without covering the exposure subject. The inventive x-ray system in principle can have an arbitrarily designed diaphragms with variously arranged individual diaphragm elements. Preferably, the diaphragm allows asymmetric adjustment with regard to a diaphragm center point. In a preferred exemplary embodiment, however, the diaphragm is designed such that the diaphragm elements can be radially moved forward and backward in the direction of the diaphragm center point at different angles, meaning from various directions. Each diaphragm element has an inner edge proceeding toward the diaphragm center point and perpendicular to the movement direction. Such a diaphragm can have 4, 6, 8 or more individual elements. Depending on the number of elements, the diaphragm can be designed rectangular, hexagonal, octagonal etc. with regard to its inner contours. The diaphragm elements, however, in principle can exhibit any other arbitrary shape. The x-ray system 1 shown in FIG. 1 has a height-adjustable x-ray source 2 mounted on an emitter stand 6 with a depth diaphragm 3 mounted directly in front of it, which is constructed and operable according to the invention. A digital x-ray detector 4 with a scattered-ray grid 5 in front of it is height-adjustably mounted on the image acquisition side to a receiver stand 7. To generate an x-ray exposure of a subject O, the subject O is positioned in the beam path between the depth diaphragm 3 and the scattered-ray grid 5. The x-ray radiator 2, the depth diaphragm 3 and the digital detector 4 are respectively connected via control lines, data lines and/or supply lines with a control device 8 which contains an x-ray voltage generator and a system control 13, with which image acquisition using the individual components 2, 3, 4 is controlled. Components of the system control 13 are a position calculation unit 14 in order to calculate the positions of the individual diaphragm elements 3a, 3b of the depth diaphragm 3 and a diaphragm control 15 which controls the individual diaphragm elements 3a, 3b or actuators therefor (such as, for example, step motors) to adjust the diaphragm elements 3a, 3b associated with the diaphragm elements 3a, 3b. Moreover, connected to the system control 13 is an image computer 9 in which, among other things, an image analysis device 16 is implemented. The image computer 9 is connected via a data line with the digital detector 4 in order to read out the data generated thereby and to generate the desired x-ray images. These x-ray images can then be displayed on a connected supervision monitor 10. Operation of the image computer 9 and the control device 8, in particular of the system control 13, is possible with the aid of the supervision monitor 10 as well as appropriate user interfaces, here a mouse 11 and a keyboard 12. In addition to the shown components, the x-ray system 1 also can have further components that are typically present in or at such x-ray systems, such as, for example, an interface to connect to a computer network, in particular a radiological information system (RIS) and/or an image archiving and communication system (PACS). Such further components however, are not shown for clarity. A method for correctly setting the diaphragm elements according to the invention in an x-ray system 1 according to FIG. 1 is explained in the following, using FIGS. 2 and 3. First, immediately before the actual x-ray exposure, initiated by the system control 13, a subject localization exposure OA is acquired with the detector 4 in advance with a very low dose (for example a hundredth of the dose used for the actual x-ray exposure) given a wide-open depth diaphragm 3. The acquisition of this “pre-shot” ensues approximately one second or less before the actual x-ray exposure. The digital detector 4 is read out at this time and the data are transmitted to the image computer 9, where the data are processed in an image analysis device 16. A direct radiation detection is implemented next, which separates the sites of the direct radiation on which the x-ray radiation strikes unattenuated on the detector 4 from the points of the subject region. The result of the calculation is a binary representation of the subject localization exposure, in which the image points of the subject region are coded with 1 and the image points of the direct radiation region are coded with 0. Such a binary subject localization exposure OA is schematically shown in the left half of the FIG. 2. The direct radiation region DB and the subject region OB are clearly distinct from one another in such a binary representation, such that in particular the contours K of the examination subject O can be easily recognized. As can be seen from FIG. 3, the subject localization exposure OA is a projection P of the examination subject O imaged from the x-ray source 2 on the detector plane DE. For the further calculations, for simplicity the following assumptions are made in the exemplary embodiment: a) All calculations occur in a coordinate system having an origin S at the focal spot of the x-ray source 2. b) The diaphragm plane BE in which the individual diaphragm elements 3a, 3b can be moved toward one another to close the diaphragm 3 and the detector plane DE lie exactly at right angles to the primary x-ray beam direction R, meaning at right angles to the direct connecting line between the x-ray source 2 and the detector 4. This direction is in the following the z-axis of the coordinate system. c) The other two coordinate axes x and y are perpendicular to this z-axis, and are oriented corresponding to the rows and columns of the active matrix of the digital detector 4. d) The diaphragm 3 has four individual diaphragm elements (3a, 3b, 3c, 3d) that can be moved toward one another from the right, from the left, from below and from above, these movement directions proceeding along the coordinate axes x and y (see FIG. 2). Although these assumptions significantly simplify the calculations, they are not absolutely necessary. Insofar as other forms of diaphragms or other geometric arrangements (such as, for example, an angular irradiation or the x-ray radiation or rotation of the x-ray source and/or of the detector plane and/or of the diaphragm plane) are provided, correspondingly more position data must be considered and incorporated into the calculation. If necessary, in such cases the selection of another coordinate system can be useful. With the aid of the subject localization exposure OA, the subject borders are first determined in order to establish how far the individual diaphragm elements 3a, 3b, 3c, 3d move in the direction of the exposure subject O, meaning how far they can be moved toward one another without overlapping the electrically-conductive structure O in the projection P. This depends on, among other things, the geometric arrangement and shape of the individual diaphragm elements 3a, 3b, 3c, 3d. It is normally reasonable to first determine the points Pa, Pb, Pc, Pd on the contour K of the exposure subject O which, in the subject localization exposure OA, form an outermost point of the contour K in the direction of the respective diaphragm element 3a, 3b, 3c, 3d. In the present case, this means the point Pa farthest to the right, the point Pb farthest to the left, the uppermost point Pc and the lowermost point Pd of the contour K are sought. Insofar as the individual diaphragm elements 3a, 3b, 3c, 3d are moved together to the extent that they respectively—viewed in the projection P—contact these points Pa, Pb, Pc, Pd, the direct radiation region DB is gated as much as possible without the diaphragm 3 covering the subject O itself (see FIG. 2, right side). In the selected geometric arrangement, the coordinates of these points Pa, Pb, Pc, Pd are relatively simple to determine, in particular when the subject localization exposure OA has already been converted into the binary representation in which the subject region is coded with 1 and the direct radiation region is coded with 0. For this purpose, only the image pixels coded with 1 whose “coordinates” in the image matrix exhibit the largest and the smallest x-value or, respectively, the largest and the smallest y-value are to be sought. This can be implemented extraordinarily quickly and simply by calculation techniques. It is then only necessary to calculate these “boundary coordinates” (up to which an inward adjustment of the diaphragm elements 3a, 3b, 3c, 3d is possible without overlapping the subject O) found in the detector plane DE in the projection P back to the diaphragm plane BE. This is shown in FIG. 3 using the diaphragm elements 3a, 3b. Since both diaphragm elements 3a, 3b in the exemplary embodiment are arranged such that they can only be moved inward or outward in the direction of the x-coordinate, only the x-coordinate is significant within the detector plane DE or the diaphragm plane BE. Further significant coordinates are the distance zD (fixed in advance anyway) of detector plane DE and the distance zB of the diaphragm 3 from the origin S of the coordinate system, meaning from the focal spot of the x-ray source 2. Using a simple beam set calculation, the coordinate x3a of the “boundary position” (up to which the inner edge of the diaphragm element 3a can be moved inward without covering the subject O) can be calculated according to the formula x 3 a = x 3 b · z B z D from the x-coordinate XPa of the found boundary point Pa on the contour K of the exposure subject O projected on the detector plane DE. In the same manner, the coordinate x3b of the “boundary position” for the opposite diaphragm element 3b is obtained from the coordinate xPb of the point Pb in the subject localization exposure OA. A calculation for the upper and lower diaphragm elements 3c, 3d can likewise ensue, for which the y-coordinates are used. After the coordinates x3a, x3b (or y3c, y3d) of the boundary positions have been calculated, these are transferred to the diaphragm control 15, which controls the motorized actuation (not shown) of the individual diaphragm elements 3a, 3b, 3c, 3d such that the diaphragm elements 3a, 3b, 3c, 3d are to be moved toward one another until the inner edges of the diaphragm elements 3a, 3b, 3c, 3d arrive directly on the calculated boundary coordinates x3a, x3b, y3c, y3d. Alternatively, the adjustment can ensue such that the inner edges lie at a predetermined small distance outside of the calculation boundary coordinates. Insofar as the detector plane DE and/or the diaphragm plane BE are slanted to the primary x-ray beam direction R, meaning slanted to the z-axis, the calculations are somewhat more complicated. The z-coordinates z3a, z3b, zPa, zPb must then also each be calculated. For example, the coordinates xB1, yB1 of an arbitrary point in the diaphragm plane BE result from the coordinates xD1, yD1 of the corresponding point in the detector plane DE, i.e. in the subject localization exposure OA, according to the formulas: x B1 = x D1 · z B1 z D1 and y B1 = y D1 · z B1 z D1 wherein zB1 and zD1 are the z-coordinates of the appertaining points. FIG. 4 shows an alternative exemplary embodiment of a depth diaphragm 3′ which has a total of 8 different diaphragm elements 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h. As in the exemplary embodiment according to FIG. 2, four of these diaphragm elements 3a, 3b, 3c, 3d can be moved toward the subject from the right, left, above or below. Moreover, the depth diaphragm 3′ has four additional diaphragm elements 3e, 3f, 3g, 3h, offset by 45°, which can be correspondingly moved toward the diaphragm center point at 45° angles. As can be clearly seen from FIG. 4, a significantly better adaptation to the contour K of the exposure subject O is possible with such a diaphragm 3′ having a number of diaphragm elements. As the exemplary embodiments show, a very rapid and relatively precise adaptation of the diaphragm 3, 3′ to the examination subject O is possible in a very simple manner with the aid of the inventive method, such that a subsequently x-ray exposure is generated under optimal conditions. Possible image artifacts due to deep radiation are reduced or largely prevented, Manual adjustment of the optimal diaphragm position is superfluous. Moreover, no elaborate special design of the detector or additional detector evaluation circuit is necessary for this purpose. The designs shown in the figures and geometric arrangements are only exemplary embodiments. Arbitrary variations of these exemplary embodiments are thus possible in a wider scope without abandoning the framework of the invention. Although the invention was predominantly specified in the example of x-ray systems in the medical field, usage of the invention is not limited to this field, but the invention can also be used in scientific and/or industrially used x-ray systems. Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art. |
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048511870 | claims | 1. Nuclear reactor fuel assembly, comprising a fuel assembly box having sides, an upper end and corners; a head plate disposed in said fuel assembly box; fuel rods containing nuclear fuel being disposed in said fuel assembly box and guided in leadthroughs formed in said head plate, at least some of said fuel rods being secured to said head plate in said leadthroughs; a corner bolt standing on top of said head plate; a cross bar disposed inside one of said corners at said upper end of said fuel assembly box on said corner bolt; an angle element having an outer surface and being adapted to said fuel assembly box; two leaf springs each being disposed on said outer surface of said angle element at a respective one of said sides of said fuel assembly box and extending in longitudinal direction of said fuel assembly box; a screw bolt firmly screwed to said fuel assembly box and said angle element at said corner bolt, said screw bolt having an expansion shaft with a reduced diameter, and a bolt head having two ends and being disposed on top of and supported on said angle element, said bolt head having an outer surface with an annular recess formed therein between said ends of said bolt head defining a coaxial bolt head shaft with a reduced diameter, said coaxial bolt head shaft being disposed in a bore formed in said angle element between said ends of said bolt head; and a transverse pin being disposed in said bore and having one end protruding into said annular recess in said bolt head. 2. Fuel assembly according to claim 1, wherein said transverse pin extends in radial direction of said bolt head shaft. 3. Fuel assembly according to claim 1, wherein said transverse pin is a screw. 4. Fuel assembly according to claim 2, wherein one of said leaf springs is firmly screwed to said angle element with said screw. 5. Fuel assembly according to claim 1, wherein said expansion shaft has a smaller diameter than said coaxial bolt head shaft. |
description | 1. Field of the Invention The present invention relates to a heat control method and a heat controller, and more particularly to a heat control method and heat control apparatus suitable for use in heat control of heat generated by electronic equipment mounted aboard a space vehicle including a man-made satellite and a spaceship. 2. Related Art In general, in a space vehicle traveling through a vacuum environment, radiation of heat into space via the outer skin of the space vehicle serves as a means of heat regulation for the space vehicle. For this reason, many techniques have been developed to prevent a great increase or a great decrease in temperature and for maintaining the temperature within an appropriate range when there are large changes in the amount of internally generated heat within the space vehicle. For example, the approach of providing a temperature-control circuit separate from the electronic equipment, and that of using a thermal louver system, such as shown in FIG. 6 of the Japanese unexamined patent publication (KOKAI) No.11-217562 are known. The provision of a separate temperature-control circuit, however, not only increases the mass of the space vehicle and the amount of energy consumed, but also leads to an inevitable increase in the internal volume of the space vehicle, and increases the number of moving parts used therein, which leads to problems of low reliability and lifetime. In Japanese patent No. 2705657, there is shown a method whereby a phase-transition substance is provided between a stable heat source within a man-made satellite and a component of the man-made satellite having a heat radiating surface exhibiting great thermal variations, wherein temperature control is performed, the phase-transition substance having a small thermal conductivity at a high temperature and a large thermal conductivity at a low temperature. However, the above-noted constitution with regard to thermal conductivity at a low-temperature phase and thermal conductivity at a high-temperature phase is the reverse of the constitution of the present invention, to be described below, making efficient temperature control impossible. In Japanese patent No. 2588633, there is disclosure of a temperature controller for electronic equipment in a space vehicle, this being formed by a vessel into which a phase-change substance is sealed, a heat pip in intimate contact with the vessel, and an electric heater in intimate contact with an outer surface of the vessel. However, because additional equipment requiring a separate heater increases in weight, this is not suitable for use in a space vehicle. Additionally, in Japan patent 2625821, there is disclosure of a heat controller for a man-made satellite, in which a phase-transition substance having a low infrared radiation efficiency at a high-temperature phase, and having a high infrared radiation efficiency at a low-temperature phase is disposed between a piece of payload equipment temperature control and a heat sink. However, the constitution in this heat controller with respect to the infrared radiation efficiencies at low- and high-temperature phases is the reverse of that in the present invention, described below, and it is impossible to perform efficient temperature control. In the Japanese unexamined patent publication (KOKAI) No.63-207799, a configuration in which a single phase-change substance made of vanadium dioxide is disposed between a piece of payload equipment and a heat sink. However, this uses a different phase-change substance than the present invention, which is described below, the method of use thereof is also different, and it does not enable efficient temperature control. In the Japanese unexamined patent publication (KOKAI) No.11-217562, as shown in FIG. 2, there is a proposal of, rather than relying on a mechanical principal, simply using the heat radiation characteristics of a phase-change substance made of perovskite Mn oxide or the like, used in the heat controller to control the temperature. Specifically, the example shown is one in which a phase-change substance 1 is directly attached to a heat radiating surface 5 of the object 3, which is a piece of electronic equipment requiring heat control. In the above-noted examples of known technology, however, the phase-change substance used is one type, perovskite Mn oxide or the like, so that at high temperatures the heat radiation efficiency is high and at low temperatures the heat radiation efficiency is low. In a heat controller using the above-noted known phase-change substance, because it is necessary to achieve a high radiation efficiency with the phase-change substance alone at a high-temperature phase, it was necessary to have a thickness of several hundred microns. In the case of using perovskite Mn oxide as a phase-change substance, because of the high density (6.6 g/cm3) of this substance, at a thickness of 200 μm, for example, the weight of the required amount of material would be as much as 1.3 kg/m2. Furthermore, because this phase-change substance is a ceramic material and having hard condition, it has the drawback of making it impossible to achieve a phase-change substance that is both thin and flexible. Although this phase-change substance has only ⅓ to ⅕ the mass of a thermal louver having the same function and which is opened and closed by a blade or bi-metal element having the same function, this is still insufficient to meet the stringent weight requirements of a space vehicle, and there is a need for even further reduction in mass. Additionally, because the phase-change substance is a solid and does not exhibit flexibility, it is difficult to mount it to an object having a curvature, thereby limiting its scope of application. The shape of a space vehicle includes curved surfaces, and if mounting were possible to these surfaces, there would be a further enhancement in the range of applicability. However, as long as use is limited to a single layer of the above-noted phase-change substance of the past, it was difficult to achieve a practical heat controller in the past. Accordingly, it is an object of the present invention to improve on the above-noted drawbacks of the prior art, by providing a heat controller and a method for controlling heat, which is lighter and higher in performance than a heat controller having equivalent heat radiation characteristics in the past. It is a further object of the present invention to provide a heat controller wherein a phase-change substance, which in the past needed to have a thickness of several hundred microns or more, is formed as a film having a thickness of approximately several microns on a low-density base material, and which has heat radiation characteristics equivalent to a heat controller in the past. It is yet another object of the present invention to provide a heat control and a method for controlling heat in which flexibility is imparted so as to enable application to an object having curvature. To achieve the above-noted objects, the present invention adopts the following described basic technical constitution. Specifically, a first aspect of the present invention is a heat controller in which a composite material formed by combining a base material radiating a large amount of heat at a high-temperature phase with a phase-change substance having insulation properties at a high-temperature phase, having metallic properties at a low-temperature phase, radiating a small amount of heat at a low-temperature phase, and having a high reflectivity in the thermal infrared region at a low-temperature phase, so as to control the temperature of an object. A second aspect of the present invention is a method for controlling heat, whereby a composite material formed by combining a base material radiating a large amount of heat at a high-temperature phase with a phase-change substance having insulation properties at a high-temperature phase, having metallic properties at a low-temperature phase, radiating a large amount of heat at a high-temperature phase, radiating a small amount of heat at a low-temperature phase, and having a high reflectivity in the thermal infrared region at a low-temperature phase is mounted either directly or indirectly to an object, so as to control the temperature thereof. By adopting the above-noted technical constitution, a heat controller and a method for controlling heat according to the present invention achieve characteristics equivalent to a heat controller of the past that used a phase-change substance, and provide a heat controller that can be made lighter in weight. More specifically, in the present invention, a phase-change substance 1 having a thickness of several microns (μm) to 30 microns (μm) and having insulation properties at a low-temperature phase and metallic properties at a high-temperature phase is formed by a coating method, a printing method with a thick film, a vapor deposition method or the like, on a low-density base material made of silicon, alumina, partially stabilized-zirconia, or the like, having a thickness of 10 to 100 microns (μm) with sufficient strength and toughness and having a high radiation ratio, the resulting composite material being mounting so as to be in good thermal contact with an object requiring heat control, thereby forming a heat controller with a simple configuration. Additionally, by using a flexible foil or film as the base material, application of the heat controller to electrical equipment having curvature is possible, thereby broadening the range of application of the heat controller and enhancing the degree of freedom. Embodiments of a heat controller and a method for controlling heat according to the present invention are described in detail below, with references made to relevant accompanying drawings. Specifically, FIG. 1 is a drawing showing a specific embodiment of a heat controller 10 according to the present invention, this drawing showing a heat controller 10 in which base material 2 radiating a large amount of heat at a high-temperature phase is combined with a phase-change substance 1 having insulating properties at a high-temperature phase, having metallic properties at a low-temperature phase, radiating large amount of heat at a high-temperature phase, radiating a small amount of heat at a low-temperature phase, and having a high reflectivity in the thermal infrared region at a low-temperature phase, thereby forming a composite material 4 so as to control the temperature of an object 3. The phase-change substance 1 used in the present invention preferably has a thickness in the range from one to 30 microns (μm). The base material 2 used in the present invention has a thickness that is greater than that of the phase-change substance 1, and preferably a thickness in the range from 10 μm to 100 μm, and more preferably a thickness in the range from 30 μm to 50 μm. In the present invention, a method usable for laminating the above-noted phase-change substance 1 and the base material 2 is, for example, that of laminating the phase-change substance 1 having a thickness of one to several microns onto the surface of the base material 2 by a coating method in that the phase-change substrate is grinded into powdered condition,a printing method with a thick film in that a paste like phase-change substance is printed and baked,or a vapour deposition method or the like, and additionally the base material 2 is mounted on a surface of the object 3 the temperature of which is controlled with a good thermal contact therebetween. It is desirable that the phase-change substance 1 used in the present invention be a perovskite oxide, such as perovskite Mn oxide. Specifically, perovskite oxides that can be used in the present invention are perovskite oxides including Mn, the chemical composition of which can be expressed in the general form A1-xBxMn (where A is at least one rare earth ion selected from the group consisting of La, Pr, Nd, and Sm, and B is at least one alkali earth metal ion selected from the group consisting of Ca, Sr, and Ba). In the present invention, it is also possible to use a corundum vanadium oxide including Cr, the chemical composition of which can be expressed in the general form (V1-xCrx)2O3. The base material 2 used in the present invention can be silicone, alumina, partially stabilized-zirconia, or the like, and it is desirable that this base material 2 exhibit flexibility, in the form of a sheet or film, so that it can be bent or curved. In the present invention, it is desirable that the composite material 4 be affixed, either directly or indirectly via an appropriate heat-conducting substance, to a surface of the object 3, which is a heat-generating body, and desirable that an appropriate adhesive be used to achieve a thermal joining to the object. Additionally, the object 3 in the present invention is not restricted to being a flat-surface part of a spacecraft, and can also be any non-flat part thereof, including spherically curved parts, simple-curved parts, or parts exhibiting surface unevenness, and the heat controller 10 according to the present invention can be affixed to any such surface of the object 3. The object 3 in the present invention encompasses a man-made satellite, a space vehicle, or the like, and includes electrical and electronic equipment used in a space vehicle. The configuration and operation of the heat controller 10 according to the present invention is described in further detail below. Specifically, with regard to the action and operation of the heat controller 10 according to the present invention, it is basically possible to understand the optical characteristics in terms of the behavior of the electrons and matrices of the base material, and if the substance is a good conductor, the reflectivity and dielectric constant thereof can be expressed as a light frequency and the characteristic plasma frequency of the substance. Given the above-noted relationship, the thickness required of the phase-change substance for light reflection in the thermal infrared region at a low-temperature phase, in which the substance becomes metallic, can be much shorter than the electromagnetic waves incident to the surface thereof, so that for the thermal infrared region in which the wavelength is in the order of 10 μm, it is sufficient for the phase-change substance to have a thickness of 1 μm or greater to achieve a sufficiently high reflectivity and low radiation ratio. In the case in which the substance is an insulator, if the thickness dose not exceed the wavelength of the incident electromagnetic waves, sufficient absorption and radiation are not be achieved. From the above-noted characteristics of the phase-change substance 1, in the case in which the object 3 is at a low temperature, the amount of heat radiated by the phase-change substance 1, which is thermally joined to the object 3 is small, so that the amount of heat radiated into the external environment from the object 3 can be made small, thereby preventing a drop in the temperature of the object 3. In contrast to the above situation, in the case in which the object 3 is at a high temperature, the phase-change substance 1 thermally joined thereto becomes an insulator, so that, although a phase-change substance 1 having a thickness of several microns cannot provide a sufficiently high radiation ratio in the thermal infrared region of several tens micron, the heat radiated by the base material 2 therebeneath, which has a high radiation ratio, passes through the phase-change substance 1, thereby making the amount of heat radiated from the surface of the phase-change substance 1 large. By virtue of the above, it is possible to radiate a large amount of heat from into the external environment from the object 3, thereby limiting a rise in the temperature of the object 3. In the heat controller 10 according to the present invention, when the temperature of the object 3 drops, because the temperature of the base material 2 that is thermally joined thereto also drops, the temperature of the phase-change substance 1 that is applied thereover by painting or vapor deposition or the like also decreases. If the phase-change substance 1 drops below its phase-transition temperature, the radiation ratio thereof decreases, so that the amount of heat radiated to the external environment decrease, making it possible to limit the decrease in temperature of the object 3. In contrast to the above situation, when the temperature of the object 3 increases, the temperatures of the base material 2 and the phase-change substance 1 thermally joined thereto also increase. Although it is not possible for the phase-change substance 1 to radiate sufficient heat because of its thinness, the heat radiated from the base material 2 forming the underlayer thereof, which has a high heat radiation ratio, passes through the phase-change substance 1, it is possible to achieve a large amount of heat radiated from both of these elements combined. For this reason, there is an increase in the amount of heat radiated into the external environment, thereby enabling a limitation of the temperature rise in the object 3. Another specific embodiment of a heat controller 10 according to the present invention is described below, with reference made to FIG. 3. Specifically, in this embodiment of the present invention, a flexible substance is used as the base material 2, a phase-change substance 1 having a thickness of several microns to 30 microns being applied by a printing method with a thick film, a coating or vapor deposition or the like onto a flexible base material 2 having a thickness ranging from several microns to 100 microns, and further the base material 2 is mounted to a surface of the object 3, which has a curved surface and the temperature of which is to be controlled, so that the base material 2 is in intimate thermal contact therewith. Silicon, alumina, partially stabilized-zirconia, or the like, can be used as the flexible base material 2. In a heat controller having a configuration as noted above, when the temperature of the object 3 decreases, the temperature of the base material 2 thermally joined thereto also decreases, so that the temperature of the phase-change substance 1 formed thereover by a printing method with a thick film, a coating method, vapor deposition method or the like also decreases. When the phase-change substance 1 drops below its phase-transition temperature, the radiation ratio thereof decreases, so that the amount of heat radiated into the external environment decreases, making it possible to limit the decrease in temperature of the object 3. In contrast to the above situation, when the temperature of the object 3 increases, the temperatures of the base material 2 and the phase-change substance 1 thermally joined thereto also increase. Although it is not possible for the phase-change substance 1 to radiate sufficient heat because of its thinness, the heat radiated from the base material 2 forming the underlayer thereof, which has a high heat radiation ratio, passes through the phase-change substance 1, it is possible to achieve a large amount of heat radiated from both of these elements combined. For this reason, it is possible to limit the temperature rise in the object 3. Yet another embodiment of a heat controller according to the present invention is described below, with reference made to FIG. 4. Specifically, in this embodiment of the present invention, a reflective sheet 6, which reflects visible light is laminated to the surface of the phase-change substance 1 on the opposite side from the surface to which the base material 2 is laminated, thereby forming a composite material 7. More specifically, in the heat controller 10 according to this embodiment of the present invention, as shown in FIG. 4, a phase-change substance 1 having a thickness of several microns is affixed by printing method with a thick film, a coating method ,vapor deposition or the like to a base material 2 having a thickness of 30 μm to 50 μm, and a base material 2 is mounted to a surface of the object 3 so that it is in intimate thermal contact therewith. FIG. 5 shows a graph indicating data of temperature dependent emissivity of a thick film made of La0.8Sr0.075Ca0.125MnO3 and having a thickness of 10 μm, which being formed by a printing method with a thick film on a surface of an Yttria stabilized zirconia substrate having a rectangular configuration of 50 mm by 50 mm with a thickness of 50 microns. And this graph especially shows a total hemispherical emittance thereof measured under the temperature between 170K to 380K. Note that, this graph shows an abrupt change in the emittance below 240K which is a transition temperature and it shows that it is metallic in a low temperature area and insulation characteristic in a high temperature. Additionally, a sunlight reflective sheet 6, which has the properties of passing infrared light and reflecting visible light, is disposed over the phase-change substance 1. The phase-change substance 1 has a low reflectivity (approximately 0.3) with respect to the sunlight region (0.3 to 2.5 μm), and has a high absorption rate with respect to sunlight. Therefore, if the phase-change substance 1 is disposed so that sunlight is directly incident thereto, the heat controller 10 itself will absorb a large amount of heat, this being a disadvantage in terms of heat radiation. To solve this problem, as shown in FIG. 4, a sunlight reflective sheet 6 having the characteristics described above is disposed so as to reduce the amount of heat absorbed in the visible light region. With the exception of sunlight, because the sunlight reflective sheet 6 is transparent (for example, with respect to thermal infrared), the basic operating principle of this heat controller is the same as the first embodiment of the present invention. The present invention can also be embodied as a method for heat control and, as is clear from the above-noted description of the operation of the heat controller 10, a method for heat control according to the present invention is basically a method for controlling heat in an object such as electronic equipment aboard a space vehicle, whereby a composite material 4 is formed by combining a base material 2 radiating a large amount of heat at a high-temperature phase with a phase-change substance 1 having insulation properties at a high-temperature phase, having metallic properties at a low-temperature phase, radiating a large amount of heat at a high-temperature phase, radiating a small amount of heat at a low-temperature phase, and having a high reflectivity in the thermal infrared region at a low-temperature phase, so as to control the temperature of an object, and directly or indirectly mounting this composite material 4 to an object 3 so as to control the temperature of the object 3. In a method for controlling heat according to the present invention, it is desirable that the base material 2 have a thickness that is greater than that of the phase-change substance 1. Additionally, it is preferable in the present invention that the phase-change substance 1 be a perovskite oxide, for example perovskite Mn oxide. It is additionally preferable in the method for controlling heat according to the present invention that the base material 2 have flexibility. As noted above, in a method for controlling heat according to the present invention, it is desirable that the reflective sheet 6 having reflectivity with respect to visible light be laminated to the surface of the phase-change substance 1 opposite from the surface to which the base material 2 is laminated. The composite material 4 or 7 can be affixed to a surface of the object that generates heat, either directly or indirectly via an intervening thermally conductive substance. By adopting the various technical constitutions described in detail above, a heat controller and method for controlling heat according to the present invention achieve several effects. One effect of the present invention is that of reducing the thickness of the high-density phase-change substance 1 to several microns, thereby achieving light weight. In contrast to phase-change substances used in the past, which, in order to achieve the required low-temperature phase and high-temperature phase heat radiation used alone, had a thickness of several hundred microns, the present invention uses a phase-transition substance having a thickness of only several microns combined with a low-density base material having a high heat radiation rate, thereby enabling a reduction in weight in the phase-change substance and the base material, resulting in an overall weight reduction. The present invention achieves a second effect by using a composite material that includes a flexible base material, which enhances ease of handling, while improving the degree of freedom in mounting, thereby broadening the range of applicability. The reason for the above effect is that, because in the past the thickness of the phase-change substance was several hundreds of microns, the phase-change substance lacked flexibility and needed to be mounted to a flat surface of an object, whereas with the present invention, because of the flexibility of the base material affixing is also possible to curved surfaces. |
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052590089 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, there are two sources of coolant to make up for losses of coolant in the nuclear reactor 22. A high pressure make up tank 32 is coupled by valves 34 between the coolant inlet or cold leg 38 and a reactor vessel injection inlet 42. However, the volume of the high pressure make up tank 32 is limited. A much larger quantity of coolant water is available from the in-containment refueling water storage tank (IRWST) 50, at atmospheric pressure due to vent 52, which opens from tank 50 into the interior of the containment shell 55. A valve 56 and a series of check valves 58 are provided for draining water from the refueling water storage tank 50 to the coolant circuit 62. Additional check valves and/or motor operated valves 64 are provided for recovering water from a sump 68 located inside the containment. However, these valves 58, 64 require that the reactor be fully depressurized in order to allow injection of coolant. According to the embodiment of the invention shown in FIGS. 1 and 2, a nuclear reactor 22 is depressurized by venting the coolant circuit into the containment shell 55 in a number of stages of decreasing pressure. For example, three initial stages are achieved by opening valves 82 coupled via spargers 84 between the coolant circuit 62 and the interior of the containment shell 55, the respective valves 82 in each leg being opened at successively lower levels of the high pressure makeup tank 122 and preferably being coupled in parallel legs along conduits 86, which are progressively larger for the successive stages. A final stage of depressurization is achieved by opening a valve means 92 which couples the coolant circuit 62 directly into the containment shell 55. The goal is to reduce the pressure to atmospheric pressure as quickly as practicable, whereupon coolant can be added to the coolant circuit by gravity feed at ambient pressure in the containment 55, while preventing severe thermal and hydraulic loads, undue loss of coolant, and other dangerous effects. Preferably, in each case, two serial valves are provided for each valve means along a respective conduit leg, as redundant shutoff means for safety purposes. Such valves are normally intended to be operated simultaneously, and accordingly such valve pairs or sets are described herein simply as valves. Staged depressurization helps to reduce thermal and hydraulic loading. It also makes inadvertent use of the depressurization system 96 less severe. A relatively small depressurization flowpath is opened initially, and the flowpath is enlarged in stages. This is accomplished by opening successively larger flowpaths upon reaching decreased pressure setpoints, and also can be accomplished by timed opening of the valves 82, 92 for individual flowpaths. FIGS. 1 and 2 are schematic representations of the depressurization system 96 and the reactor 22, and FIGS. 3 and 4 are physical representations. The same reference numerals have been used in all the figures to identify corresponding elements. The depressurization system 96 reduces the pressure in a nuclear reactor 22 having a reactor vessel 46 disposed in a containment shell 55 and inlet piping 102 and outlet piping 104 coupled to the reactor vessel 46. At least one steam generator 110 is coupled between the outlet 104 and the inlet 102 for extracting useful power, typically driving an electrical generator. The reactor vessel 46, inlet/outlet conduits 102, 104 and steam generator connections together define a recirculating coolant path or circuit in which water heated by the nuclear fuel is circulated under pressure. A plurality of depressurizer valves 82, 92 are coupled in fluid communication with the coolant circuit 62 and at least one sparger 84 in fluid communication with an inside of the containment shell 55. The valves 82, 92 are provided with control means and/or operators for successively opening the depressurizer valves 82, 92 to effect depressurization. As additional valves or groups of valves open in stages, the coupling between the coolant circuit 62 and the inside of the containment shell 55 is increased. At the same time, the pressure in the coolant circuit 62 decreases. The depressurizer valves 82, 92 can be successively opened on actuation signals from pressure responsive valve controls or, preferably, via level responsive controls including sensors 122 associated with the high pressure makeup tank and arranged such that each successive one or each successive group of depressurizer valves 82, 92 opens at a progressively lower level setpoint. Preferably, a pressurizer tank 130 is disposed in the containment shell 55, the pressurizer tank 130 having a bottom head 132 coupled by a conduit 134 to a coolant outlet 140 of the reactor, also referred to herein as the hot leg of the coolant circuit 62. A top head 142 of the pressurizer tank 130 is coupled to at least one of the depressurizer valves 82. The depressurization valves 82 for the higher level opening stages, as shown in FIG. 1, are coupled to the inside of the containment shell 55 through a sparger 84, i.e., a fluid outlet opening at a submerged point in a water tank. The sparger has a series of holes 114 submerged in a tank of water 50, namely the in-containment refueling water storage tank. Tank 50 is vented to the inside of the containment shell 55, i.e., the tank 50 can be at atmospheric pressure. Preferably, the tank 50 is arranged by suitable valving 152 to empty via gravity into one or more of the reactor vessel 46, the coolant circuit 62 and/or the sump 68 in the bottom of the containment shell 55, thereby to cool the core in the event of an accident such as a loss of coolant accident. Inasmuch as the depressurization valves 82 for the higher level stages vent into the refueling water storage tank 50 and the tank 50 vents into the containment shell 55, the pressure of the reactor coolant circuit 62 is vented through to the containment shell 55 in this arrangement. The depressurization valves 82, 92 are coupled to the containment shell 55 via conduits 162, 164 which are progressively larger for depressurization valves 82, 92 opening at progressively lower pressures. Therefore, not only is the coupling between the coolant circuit 62 and the containment shell 55 increased due to additional conduits 162, 164 opening as pressure in the coolant circuit 62 decreases. Furthermore, the size of the flowpath for a given opening stage is larger than the flow path opening of the previously opening stage. The result is a gradual but expeditious decrease in coolant pressure. To render the change more gradual, the depressurization valves 82, 92 can be motor operated or otherwise arranged to open from fully closed to fully open over a period of time, whereby peak flows through the depressurization valves 82, 92 are limited. At least one of the depressurization valves 92 or group of valves 92 defines the last stage of depressurization, i.e., this valve or group is openable at a lowest level of the high pressure makeup tank. Valve(s) 92 couple directly between the coolant circuit 62 and the containment shell 55 by conduits 164. Preferably, this last stage opens a flowpath between a coolant outlet 140 of the reactor (the hot leg of the coolant circuit) and the containment shell 55. The depressurization valves 82, 92 preferably include a plurality of parallel valve legs 162 coupled between the coolant circuit 62 and spargers 84, submerged in the tank 50, or the containment 55 through conduit 164, coupling progressively larger ones of conduits 162, 164 to vent the pressure, and openable at progressively lower pressures as indicated by the level in the high pressure makeup tank 32. Spargers for boiling water reactors, intended to reduce pressure in the coolant circuit but not to bring the pressure to the atmospheric pressure in the containment, are typically located about 17 feet underwater, which creates a large back pressure. Additionally, flow resistance causes a further back pressure. The spargers 84 according to the invention are also submerged. However, in addition to venting into the containment 55 through spargers 84, the depressurization system 96 of the invention also vents directly to the containment 55 in the last stage of depressurization. The first stage, which vents into a sparger 84 from a pressurizer tank 130 coupled to the coolant outlet 140 of the reactor 22, has a relatively small conduit size, and thus reduces initial shock to the coolant circuit 62 when depressurization commences. The subsequent stages use larger conduit sizes. Additionally, it is possible to use a relatively slow opening form of valve 82, 92 to soften the impact of depressurization. Preferably, a first stage valve 82 opens a 4 inch (10 cm) internal diameter conduit 162 and takes approximately 20 seconds to open fully: and the second and third stage valves 82 open 8 inch (20 cm) conduits and take about 90 seconds to open fully. A slow opening form of valve reduces the peak flow rate upon opening of the valve, and thus conserves coolant. With the opening of the valves, and the successive opening of further stages having progressively larger conduit size, there is a slow and gradual increase in coupling between the coolant system 62 being depressurized and the inside of the containment shell 55. The foregoing conduit sizes are exemplary, preferred for a reactor having a capacity of about 600 MWe. The sizes can be scaled up or down to accommodate other reactor capacities and the like. Similarly, the staging can have a different number of stages than the number of stages shown in connection with the presently preferred embodiment. The final stage, which in the illustrated embodiment is the fourth stage, vents the coolant circuit 62 directly into the containment 55. Preferably, the fourth stage valve 92 opens a 12 inch (30 cm) conduit 164. This last stage valve or group of valves 92, and the conduit arrangement 164 therefor, are different in several respects from the first three stages. The fourth stage is coupled from the hot leg 140 of the coolant circuit 62 (i.e., the reactor output) directly into the containment shell 55, instead of through the pressurizer tank 130 and/or through underwater spargers 84. Although all the stages are coupled in fluid communication between the containment 55 and the hot leg 140 of the reactor, the stages with smaller conduits and/or which couple through the pressurizer 130 and through the spargers 84 have a characteristic back pressure due to the flow restrictions inherent therein. The fourth or final stage effectively brings the coolant circuit 62 down substantially to the atmospheric pressure existing in the containment shell 55. The hot leg 140 of the coolant circuit 62 (i.e., the reactor outlet) is the point where the coolant water is hottest in the circuit. Under operational conditions, the water in the hot leg is about 600.degree. F. (330.degree. C.). The water returning from the steam generator 110 along the cold leg 38 is at approximately 550.degree. F. (290.degree. C). Whereas the water is taken off by the depressurization system at its highest temperature, the reactor coolant in more effectively utilized in providing cooling. Both water and steam may be vented. As soon as the first stage opens, the system starts to draw water out of the hot leg 140, into the pressurizer 130, then out of the system and into the containment 55. Although the pressurizer 130 is a rather large tank, even with venting through the spargers 84 the flow through the pressurizer 130 is not sufficient to carry all the contents of the pressurizer 130 through to the refueling water supply tank 50. The water in the pressurizer 130 thus produces a back pressure which limits flow during the first three stages of depressurization. The first three stages thus have back pressure characteristics which the fourth stage does not have. These include the fluid pressure head of the water in the refueling water tank 50 above the spargers 84, the water elevation in the pressurizer 130, and the line flow resistance caused by the relatively smaller size of conduit 162 as compared to the final stage conduit 164. The depressurization valves for effecting respective stages of depressurization, and/or the operators which are arranged to open the valves, can be chosen with respect to the differential pressure at which the valves are expected to open during depressurization. In particular, the valve and/or operator for the final stage of depressurization is preferably openable only below a predetermined differential pressure, thereby minimizing the possibility that the last stage will be opened prematurely. Steam and water in the hot leg 140 of the reactor 22, as vented directly in the fourth stage, is carried through a sufficiently large opening defining the hot leg 140 that very little flow resistance occurs between the reactor vessel 46 and the point of venting through the fourth stage conduit 164 and valve 92. Thus the direct connection of the hot leg 140 with the containment 55 in the fourth stage, and the large diameter of the hot leg 140 and fourth stage conduit 164, are such that the pressure in the reactor vessel 46 and the coolant circuit 62 comes substantially fully down to the ambient atmospheric pressure in the containment 55. It is of course the pressure in the reactor vessel 46 which is most important, because the intent of depressurization is to enable water to be drained into the reactor by low pressure means, especially by gravity from the in-containment refueling water storage tank 50. Preferably, the stages each have a plurality of valves 82, 92 coupled in a series, for example as shown by valves 168. Both valves 168 in the series connection are normally closed. Having two valves in series minimizes leakage and makes it unlikely that any of the stages will be opened or left open inadvertently. Both valves 168 in each stage can be opened via actuation signals from a controller 172. The first three stages can have motor controlled valves 82, powered or geared to achieve the timed opening discussed above. Preferably these valves 82 are powered from batteries. The fourth stage can use a different type of valve to prevent common mode failure and thereby increasing reliability. For example, the fourth valve 92 can be operated pneumatically from a dedicated air cylinder. Alternatively, the fourth stage valve 92 can be explosively operated. For further redundancy, in a reactor having more than one steam generator circuit, a valve and different type of operator can be associated with each of a plurality of hot legs 140 coming out of the reactor vessel 46, again avoiding the possibility of common mode failure. Where there are two loops in the steam generator portion of the reactor design, the pressurizer 130 and its initial stage valves 82 can be coupled to one hot leg, and the final (e.g., fourth) stage valve 92 can be coupled to the other hot leg. By coupling the initial stages through the pressurizer and the final stage directly, flow is limited during the initial stages, and the pressurizer surge line can be smaller. Referring to FIGS. 3 and 4, each of the coolant loops is partly enclosed in a coolant loop compartment 175 having concrete walls 177. The fourth stage can open into a respective coolant loop compartment 175. The concrete walls 177 provide shielding for plant personnel, and it is unlikely that plant personnel will be in the area of the coolant loop compartment 175 during plant operations, because radiation levels there are high. One disadvantage, however, is due to the fact that there is some equipment housed in the cooling loop compartment, such as instrumentation coupled to the loops to monitor temperature and flow, and electrical connections for the reactor coolant pumps. Whereas the discharge from the depressurization valve 92 may wet such equipment, some cleanup would be needed before restarting the plant following depressurization. As an alternative, the fourth stage can be coupled to an outlet at the refueling cavity 181 (see FIGS. 3 and 4). The refueling cavity 181 is a stainless steel lined pit designed to be flooded during refueling operations, and is an advantageous place to direct the output of the fourth stage. The reduction of pressure through the first three stages can reduce the pressure in the coolant circuit 62 to about 50 psi prior to opening of the fourth stage. The opening of a relatively large conduit 164 to the containment in the fourth stage brings the coolant circuit 62 down to a low pressure, without producing large discharge forces and flow rates. Depending on the extent of boiling still occurring in the reactor vessel 46, some minimal pressure may remain over atmospheric pressure; however, the staged depressurization efficiently reduces the pressure to a point where it is possible to add coolant from a refueling tank at atmospheric pressure. Sufficient water is contained in the refueling water storage tank that its gravity head alone can overcome this remaining pressure. Another feature of the embodiment shown in the drawings is that the respective valves 82, 92 in each stage can be opened individually and then closed during normal plant operating conditions to verify that the valves 82, 92 are operating properly. As shown in FIG. 2, several small solenoid valves 192 can be provided in test legs 194 leading to the sparger 84, operable to isolate each of the serially coupled valves in the three stages for testing at reduced pressure conditions. Pressure conditions are reduced because the test conduits 196 comprise small (e.g., 0.75 inch or 2.0 cm) internal diameter conduits. Testing at low differential pressure reduces the possibility of causing valve leakage as a result of a test. For the first three stages, two test valves 192 can isolate and test any of the six valves in the first three stages. A similar arrangement for testing the fourth stage is shown in FIG. 3. In connection with testing of the fourth stage, a test valve arrangement of this type is required for testing, because the fourth stage valves are designed for operation at lower pressures than those typical of plant operation. The test valves can be used during a cool-down leading to a refueling outage, for conducting a more rigorous test of the automatic depressurization system and its valves. The test can be conducted, for example, at intermediate pressures in the range of 400 to 600 psig. For such a test, the test valves 192 can be arranged such that each tested valve 82 or 92 along the depressurization paths opens under a large differential pressure, by operating selected ones of the test valves 192. For example, the upstream depressurization valve in each pair can be tested by opening the test valve downstream thereof, leading to the spargers 84. The downstream depressurization valve in the pair can by tested by opening the upstream test valve to obtain elevated pressure leading into the depressurization valve. In each case, the small conduit size of the test system limits the flow occurring during the test, and reduces the impact on the downstream refueling water storage tank as well as the atmosphere in the containment, in particular keeping radiation to acceptable levels. Routing the flow to an appropriate drain means apart from the refueling water storage tank 50 is another possibility. The invention having been disclosed, a number of alternatives will now become apparent to those skilled in the art. The foregoing embodiments are illustrative, and are not intended to limit the particulars of the invention in which exclusive rights are claimed. Reference should be made to the appended claims rather than the discussion of preferred embodiments, in order to assess the scope of the invention in which exclusive rights are claimed. |
claims | 1. A method for transporting a source pin in a Positron Emission Tomography (PET) system having a transmission ring, said method comprising: aligning the transmission ring with a source pin within a storage device having a magnetic force holding the source pin in place; and moving the source pin from the storage device to the transmission ring using a magnetic force greater than the magnetic force of the storage device. 2. A method in accordance with claim 1 wherein said aligning the transmission ring comprises aligning the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force and an electromagnet force holding the source pin in place, said moving the source pin comprises moving the source pin from the storage device to the transmission ring using a magnetic force greater than the magnetic force of the permanent magnet and less than the combined magnetic force of the electromagnet and the permanent magnet. claim 1 3. A method in accordance with claim 1 wherein said aligning the transmission ring comprises aligning the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force and an electromagnet force holding the source pin in place, said moving the source pin comprises moving the source pin from the storage device to the transmission ring using a magnetic force at least twice greater than the magnetic force of the permanent magnet and less than the combined magnetic force of the electromagnet and the permanent magnet. claim 1 4. A method in accordance with claim 1 wherein said aligning the transmission ring comprises aligning the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force of at least about 5.34 Newtons (N) and an electromagnet force of at least about 23.6 N holding the source pin in place, said moving the source pin comprises: claim 1 de-energizing the electromagnet force; and moving the source pin from the storage device to the transmission ring using a magnetic force of at least about 10.67 N. 5. A method in accordance with claim 1 further comprising moving the source pin from the transmission ring to the storage device using the magnetic force of the storage device. claim 1 6. A method in accordance with claim 5 further comprising sensing a presence of the source pin in the storage device using a proximity sensor. claim 5 7. A method in accordance with claim 6 wherein said sensing a presence of the source pin comprises sensing a presence of the source pin in the storage device using a proximity sensor comprising a normally open Negative-Positive-Negative (NPN) inductive sensor. claim 6 8. A method in accordance with claim 6 wherein said sensing a presence of the source pin comprises axially sensing a presence of the source pin in the storage device using a proximity sensor. claim 6 9. A method in accordance with claim 8 wherein said axially sensing a presence of the source pin comprises axially sensing a presence of the source pin in the storage device using a proximity sensor comprising a normally open Negative-Positive-Negative (NPN) inductive sensor. claim 8 10. An imaging system comprising: a rotatable transmission ring; a storage device adjacent said transmission ring; at least one source pin storable in said storage device, said storage device having at least two magnetic forces including a permanent magnet force and an electromagnet force holding said source pin in place; and a source of magnetic force on said transmission ring, said source configured to move said source pin between said storage device and said transmission ring. 11. A system in accordance with claim 10 wherein said source of magnetic force on said transmission ring comprises a magnetic force greater than the magnetic force of said storage device permanent magnet and less than a combined magnetic force of said storage device electromagnet and said storage device permanent magnet. claim 10 12. A system in accordance with claim 11 wherein said source of magnetic force on said transmission ring comprises a permanent magnet. claim 11 13. An imaging system comprising: a rotatable transmission ring; a storage device adjacent said transmission ring, said storage device comprises a magnetic force holding a source pin in place; and a proximity sensor positioned to sense a presence of the source pin in said storage device, wherein said rotatable transmission ring comprises a source of magnetic force stronger than said storage device magnetic force and configured to move said source pin between said storage device and said transmission ring. 14. A system in accordance with claim 13 wherein said proximity sensor comprises a normally open Negative-Positive-Negative (NPN) inductive sensor. claim 13 15. A processor configured to: align a transmission ring with a source pin within a storage device having a magnetic force holding the source pin in place; and move the source pin from the storage device to the transmission ring using a magnetic force greater than the magnetic force of the storage device. 16. A processor in accordance with claim 15 further configured to: claim 15 align the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force and an electromagnet force holding the source pin in place; and move the source pin from the storage device to the transmission ring using a magnetic force greater than the magnetic force of the permanent magnet and less than the combined magnetic force of the electromagnet and the permanent magnet. 17. A processor in accordance with claim 15 further configured to: claim 15 align the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force and an electromagnet force holding the source pin in place; and move the source pin from the storage device to the transmission ring using a magnetic force at least twice greater than the magnetic force of the permanent magnet and less than the combined magnetic force of the electromagnet and the permanent magnet. 18. A processor in accordance with claim 15 further configured to: claim 15 align the transmission ring with a source pin within a storage device having at least two magnetic forces including a permanent magnet force of at least about 5.34 Newtons (N) and an electromagnet force of at least about 23.6 N holding the source pin in place; de-energize the electromagnet force; and move the source pin from the storage device to the transmission ring using a magnetic force of at least about 10.67 N. 19. A processor in accordance with claim 15 further configured to receive a signal from a proximity sensor indicative of a presence of the source pin in the storage device. claim 15 20. A processor in accordance with claim 15 further configured to receive a signal from a normally open Negative-Positive-Negative (NPN) inductive sensor indicative of a presence of the source pin in the storage device. claim 15 21. A processor in accordance with claim 18 further configured to receive a signal from a normally open Negative-Positive-Negative (NPN) inductive sensor indicative of a presence of the source pin in the storage device. claim 18 22. A Positron Emission Tomography (PET) system comprising: a rotatable transmission ring; a storage device adjacent said transmission ring; at least one source pin sized to be storable in said storage device, said storage device having a magnetic force holding said source pin in place; a proximity sensor positioned to sense a presence of said source pin within said storage device; and a source of magnetic force on said transmission ring stronger than said storage device magnetic force, said transmission ring source configured to move said source pin between said storage device and said transmission ring. |
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046876057 | description | DETAILED DESCRIPTION OF THE INVENTION In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings. Also, in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like, are words of convenience and are not to be construed as limiting terms. In General Referring now to the drawings, and particularly to FIG. 1, there is illustrated a block diagram of the basic, successive, interrelated stages of the automated nuclear fuel rod production system of the present invention, being generally designated by the numeral 10. Each of these stages will be described in detail hereafter with reference to the process steps depicted in FIGS. 2 to 5 and the equipment schematically illustrated in FIGS. 6 to 8. However, before proceeding into a detailed discussion of the various stages of the automated system 10, a brief overview of the automated system 10 will be presented. In a first stage of the automated system 10, represented by block 12 in FIG. 1 which contains the caption, Powder Formulation & Processing, a suitable radioactive gas, such as uranium hexafluoride (UF.sub.6), is converted into another radioactive substance in powder form, such as uranium dioxide (UO.sub.2), which is then blended into a suitable composition for pellet fabrication. Next, the blended powder is formed into green pellets in a second stage of the automated system 10, being represented by block 14 in FIG. 1 and designated Pellet Fabrication. After fabrication, the green pellets are sintered, sampled, ground, inspected and stored, all of which steps are included under the heading, Pellet Processing, and represented by block 16 in FIG. 1. Concurrently, as the pellets are being fabricated and processed, the other primary part of a nuclear fuel rod, the hollow tube, is being prepared for assembly with the pellets. Block 18 of FIG. 1, called Tube Preparation, represents such activity. Finally, steps carried out in assembling the prepared tubes and stored pellets together and in inspecting the assembled fuel rod are represented by block 20 of FIG. 1 and termed Fuel Rod Fabrication & Inspection. Powder Formulation & Processing Turning now to FIGS. 2, 6 and 7, there is shown the process steps and equipment involved in the first and second stages, the powder formulation and processing stage 12 and the pellet fabrication stage 14, of the automated fuel rod production system 10. The formulation and processing of a suitable radioactive compound in powder form will be described in this section, with its formation into pellets being reserved for the next section. The first, or powder formulation and processing, stage 12 of the automated system 10 begins when, as per block 22 of FIG. 2, cylinders containing raw uranium hexafluoride (UF.sub.6) gas are released from storage as needed and installed in one of several vaporization units, such as vaporizer vessels 24 illustrated in FIGS. 6 and 7. To vaporize the UF.sub.6 gas as per block 26, the cylinders are heated to a temperature of approximately 180 degrees F. in the vessels 24 by circulating hot water sprays therein. The resulting UF.sub.6 vapor is supplied under pressure from the cylinders in the vessels 24 through a pair of gas flow lines 28 to a pair of kiln units, such as rotary kilns 30. In the preferred embodiment, as depicted in FIG. 7, a pair of the vaporizer vessels 24 are connected in flow communication with each of the kilns 30 so as to provide sufficient excess capacity to ensure a continuous supply of vapor to the kilns at the same time as a depleted one of the cylinders in one of the vessels is exchanged for a fresh cylinder. The kilns 30 implement the IDR process, as per block 32 of FIG. 2, by converting the gaseous UF.sub.6 to UO.sub.2 powder, first, through reaction of the gas with superheated steam at the feed ends of the kilns and, then, through reaction of their intermediate products with a counter-current flow of steam and hydrogen at the product ends of the kilns. The UO.sub.2 is discharged by gravity flow from the product ends of the kilns 30 to a temporary storage, as per block 34 of FIG. 2, in the form of a plurality of check hopper units 36. The check hopper units 36 which together continuously receive uranium dioxide powder from the lower end of the kilns 30 are each of a size to ensure geometric control of the UO.sub.2. Powder entering the check hopper units 36 is continuously sampled by a time proportional sampler and analyzed for acceptable quality as to fluoride and moisture content as per block 38 of FIG. 2. The moisture check is made here in order to initiate the exercise of moderation control over the powder during the blending of the same which occurs next. In the preferred embodiment seen in FIG. 7, a pair of the check hopper units 36 are connected in flow communication with each of the kilns 30 such that as at least one of the check hopper units of one pair is being filled from its respective kiln, at least one of the other check hopper units is dispensing its powder while the powder in another of the check hopper units is being sampled. With such arrangement, a sequence of operation can be implemented whereby powder is continuously dispensed from at least one of the check hopper units 36 while in-line sampling of powder is carried out at another unit. Powder of acceptable quality is discharged continuously from at least one of the check hopper units 36 via a pneumatic transfer line 40 to a plurality of blending units, such as the bulk blenders 42 seen in FIGS. 6 and 7. Powder found to be unacceptable with respect to fluoride and/or moisture is transferred via safe geometry transfer containers (not shown) to a powder rework station (not shown) for further treatment to reduce fluoride and/or moisture content. Reworked powder which meets specifications is then returned to the process stream at the blenders 42. Each of the bulk blenders 42, in the preferred embodiment, has a 5000-Kg capacity and is used to produce a homogeneous blend which meets product specifications, as confirmed by the performance of a chemical analysis per block 44 of FIG. 2. Each conical shaped blender 42, preferably being three in number, has a rotating internal screw to ensure thorough blending, as per block 46 of FIG. 2. The use of large blenders 42 reduces the number of individual blends which must be made and minimizes blend-to-blend variations. Further, because of the large capacity of the blenders 42, complete elimination of all powder from a batch of one concentration from the kiln and blender components is not now necessary before powder from another batch of a different concentration can be introduced into the blenders. Transport line diverter valves 48 associated with each of the blenders 42 are actuated to direct powder via a cyclone receiver 50 to one of the blenders while blended powder in another of the blenders is inspected as per block 52 of FIG. 2 and blended powder from the remaining blender is dispensed to pellet fabrication operations immediately downstream of the blenders. In such manner, blended powder is dispensed continuously for uninterrupted pellet fabrication. Also, as indicated by blocks 54, 56 of FIG. 2, powder from dirty and clean scrap processing, after an adequate moisture check as per block 58, can be transferred to the blenders 42 for blending. Pellet Fabrication Blended powder from the blenders 42 is transferred via a pneumatic transfer line 60 to pellet fabricating units 62, preferably two in number, which begins the second, or pellet fabrication, stage 14 of the automated system 10. The entire green pellet fabrication process is controlled and operated as an automated integrated system with the pelleting equipment of the units 62 being arranged vertically to permit gravity transfers of material and to minimize floor space requirements. The equipment is enclosed and is subject to controlled ventilation to prevent the spread of airborne particles. As per block 64 of FIG. 2, blended UO.sub.2 powder released from the one of the blenders 42 which happens to be dispensing at the time is fed on demand, via transfer line 60, into a powder compactor 66 of each of the pellet fabrication units 62 as seen in FIG. 6. In the compactor 66, powder is compacted by a slugging press into small wafers or slugs which flows downward to a granulator 68 at the next lower level of each fabrication unit 62. The inlet of the granulator 68 is close-coupled with the discharge of the compactor 66 so that the two devices operate simultaneously. As per block 70 of FIG. 2, the slugs are granulated in the granulator 68 to a composition resembling freeze-dried coffee. Next, as per block 72 of FIG. 2, the granules are combined, on a proportional basis, with a suitable lubricant, such as zinc stearate, and rolled to produce a press feed material that has improved flowability. (The zinc stearate serves as a die lubricant during pellet pressing which follows.) Finally, the granule and lubricant mixture are formed, as per block 74 of FIG. 2, into green pellets by a pellet press 76 at the lowest level of each of the fabrication units 62. The pellets are typically compacted into cylindrical bodies 5/8ths-inch long and 3/8ths-inch in diameter with a 60 percent theoretical density that equals 10.3 grams per cubic centimeter. Ordinarily, the pellet fabricating units 62, operating at a rate of only about one-half of their combined capacity, provide a continuous stream of green pellets which is sufficient for feeding the processing equipment located downstream. Thus, if one of the fabricating units 62 happens to be temporarily out of commission, the other one can take up the slack and, by operating at or near its capacity, supply the total requirement of green pellets for the next pellet processing stage 16 of the automated system 10. Pellet Processing At the beginning of the third, or pellet processing, stage 16 of the automated system 10, empty boats 78 are advanced in a procession thereof toward, while boats 80 loaded with green pellets are moved away from, the discharge of the pellet press 76 by a conveyor 82. Only an end of the conveyor 82, as depicted in FIGS. 6 and 7, is associated with the pellet fabrication units 62. Most of the conveyor 82 is seen in FIG. 8 wherein it is arranged to deliver boats to and remove boats from respective infeed and discharge ends 84,86 of a plurality of sintering furnaces 88 as well as other processing equipment to be discussed later. In addition to conveying the boats, the conveyor 82 provides in process storage of both empty and full boats. At the discharge of the fabrication units 62, the green pellets are gently loaded in an orderly array within the molybdenum sintering boats 78,80 and then moved by the conveyor 82 to a branch 90 thereof where a shuttle car 92 delivers individual loaded boats 80 to the infeed ends of the furnaces 88. A boat 80 loaded with green pellets at the infeed end 84 of one sintering furnace 88 is conveyed through the furnace by a walking beam device employed by each furnace and emerges as boat 94 loaded with sintered pellets. In each furnace 88, the pellets are sintered, as per block 96 of FIG. 3, to a specified 95 percent theoretical density in a hydrogen atmosphere at approximately 1750 degrees C. to achieve the required density and microstructure. The boat handling and furnace operations are mechanized in their entirety and monitored and controlled as an integrated system from a single control station. Multiple sintering furnaces 88, such as three in number, are used to allow excess capacity so that a continuous stream of sintered pellets can be provided to the remainder of the processing equipment even when one of the furnaces is temporarily out of commission. After the boats 94 loaded with sintered pellets exit the discharge ends of the furnaces 88, they are automatically transported by the conveyor 82 to a sampling station 97 where representative ones of the sintered pellets in each boat are randomly sampled and their density inspected, as per block 98 of FIG. 3. Low density pellets are routed by a branch (not shown) of the conveyor 82 for resintering in the furnaces 88. High density (overdense) pellets are routed to clean scrap recovery, as per block 56 of FIG. 2. Other measurements and checks are performed of the pellet samples, as per blocks 100 and 102 of FIG. 3, some of which take several days before the pellets are finally approved. Therefore, the unapproved sintered pellets are advanced through the next step in the pellet processing stage 16 and thereafter stored where they will await approval before assembly into a fuel rod. The boats 94 of unapproved sintered pellets are conveyed to one of a pair of unloading units 104, as seen in FIG. 8, where the boats are unloaded and the pellets oriented in single file are fed to one of a pair of grinding units 106. The pellets are centerless ground in a dry grinding operation, as per block 108 of FIG. 3, using a diamond grinding wheel to achieve acceptable surface finish and proper diameter. The material removed during grinding is collected by a dust collection system and the recovered swarf is collected, as per block 110 of FIG. 3, and returned to clean scrap recovery, as per block 56 of FIG. 2. The ground pellets are then fed in single file to one of a pair of inspection stations 112 where on-line diameter and surface quality inspection is carried out, as per block 114 of FIG. 3, by suitable devices paced to the operation of the grinding units 106. Also, additional tests are performed on the pellets, as per blocks 116,118 of FIG. 3. Unacceptable pellets are sorted and sent to either dirty scrap processing, as per block 54 of FIG. 2, or clean scrap processing, as per block 56 of FIG. 2, depending on the particular contaminant and/or defect associated with the pellet. Acceptable pellets are loaded, row by row, onto clean pellet trays which are then routed by a tray transfer device 120 into an auto storage and retrieval system 122, as seen in FIG. 8, to an identified storage position, as per block 124 of FIG. 3. The pellets stay in the system 122 pending receipt of quality control approval of their earlier sampling and, after approval is received, until required for fuel rod tube loading. The storage area of the system 122 is designed to hold a 3-4 day requirement of pellets. Such excess capacity ensures that continuous assembly of pellets with tubes can be accommodated while awaiting up to 2 days to receive results of laboratory tests on the pellet samples. Furthermore, tray movement into, from, and within the storage and retrieval system 122 is directed and controlled in such manner that the system has the capability to trace the location of individual trays or of groups of trays as required to maintain traceability. Tube Preparation The remaining two stages of the automated fuel rod production system 10, the tube preparation stage 18 and the fuel rod fabrication and inspection stage 20 which are arranged in tandem, are carried out concurrently with the first three stages described above. By so doing, tubes will be prepared and ready for insertion of nuclear fuel pellets by the time processing of the pellets has been completed whereby a continuous (paced) assembly line type production of fuel rods can be achieved. The steps involved in the preparation of fuel rod tubes will be described in this section, while the assembly and inspection of the fuel rods will be reserved for the final section. Referring now to FIGS. 4 and 8, the tube preparation stage 18 begins when, as per block 126, tubes are taken from storage and delivered to a tube indexer system 128, seen in FIG. 8. The tube indexer system 128 is a synchronous transporter which transfers tubes through the various preparation and inspection operations of this stage. In the system 128, multiple indexing units are used with transition and feed devices separating the units. The transition and feed devices provide a pause in the system which increases system availability. Initially, the serial number of each tube is read using an automatic image recognition device (not shown) which verifies the correct label and enters all information for the tube into the traceability system. Then the tube is indexed by the system 128 to a checker station 130 seen in FIG. 8 where, as per block 132 of FIG. 4, the tube is checked to see if it is clear internally. If the tube is not clear an operator is alerted and the tube is not indexed. From the station 130, the tube then goes to a cleaner station 134 where, as per block 136 of FIG. 4, a tube cleaner engages the tube end (normally the lower end), grips it and with a rotating action wipes the end with a cleaning material. The cleaning media is discarded to a collection can, the head of the cleaner retracts and prepares for the next cycle. The lower end of the tube is now prepared for receiving an end plug at a next, tube plugger station 138 of FIG. 8. After being moved to station 138, the tube is gripped by a clamp and, as per block 140 of FIG. 4, a plug is pressed into the tube end. Then, the plugged tube is advanced to a weld station 142, inserted into a weld chamber and, as per block 144 of FIG. 4, a girth weld is made on the tube-to-plug joint. When completed, the tube is transferred to a transition device (not shown). Between the weld station 142 and the downstream inspection operations coming up next, the tubes are surged to form a break between the two indexing transporters of the indexer system 128. Then, from the transition device, the tube is advanced to a weld physicals check station 146 seen in FIG. 8 where, as per block 148 of FIG. 4, the weld beam on the tube is checked for diameter and surface discoloration. After weld physicals check, each tube is transferred to a weighing station 150 where the tube is weighed as per block 152 of FIG. 4. Finally, the tube weld is ultrasonically inspected at station 154 of FIG. 8, as per block 156 of FIG. 4. If the weld is accepted the tube is transferred downstream to a tube transporter (not shown) where it is transferred axially in preparation for fuel pellet loading operations. Tubes with rejected bottom end welds are removed from the process stream to a repair station (not shown), as per block 158 of FIG. 4, where the tube end plug is removed and the tube is again recycled through the tube preparation operations as described above. Fuel Rod Fabrication & Inspection In the fifth and final, or fuel rod fabrication and inspection, stage 20 of the automated system 10, the fuel rod tube prepared during the previous stage 18 and pellets stored in the storage and retrieval system 122 are brought together. The UO.sub.2 fuel pellets are loaded into the tube, then a spring is inserted and an upper end plug is applied and welded to the tube, after which the tube is internally pressurized and sealed. These are the basic assembly steps. They are followed by a multiple of inspection operations, although a few checks are interspersed between the assembly steps. In a tube indexing system 160, a synchronous transporter transfers tubes through the various fabrication and inspection operations. Groups of operations are separated by a transition device of the system 160. Rods are surged at various intervals in the fabrication and inspection stage to form a break between indexing transporters. First, prepared fuel tubes are fed from the axial conveyor to a surge conveyor of the fuel rod fabrication indexer system 160. A plurality of tubes, such as 25 tubes, are accumulated and transferred onto the pellet loading table 162 in FIG. 8 where, as per block 164 of FIG. 5, a vibratory loader is actuated and approved pellets are moved into the tubes. The pellets are transferred on trays to the loading table automatically from the storage and retrieval system 122. The pellets are then swept off of the trays onto the loading table for vibratory feeding into the tubes. Following the loading operation, tubes, now referred to as rods, are transferred to a transition section and then in order are transferred to the rod indexing transporter of the indexer system 160. At this time, each rod number is scanned and stored in a file for traceability. The first station following pellet loading in FIG. 8 is the plenum gage station 166 where, as per block 168 of FIG. 5, the rod plenum is measured and then pellets added or removed depending on the plenum measurement. After plenum adjustment, the rod is weighed at station 170, as per block 172, and then the top rod end is cleaned at station 174, as per block 176 of FIG. 5, in the same manner as the bottom end cleaning operation was carried out. Thereafter, a plenum spring is inserted into each of the rods at station 178, in accordance with block 180 of FIG. 5, followed by pressing a plug into the upper end of the rod and compressing the spring therein at plugging station 182 of FIG. 8, as represented by block 184 in FIG. 5. Fabrication of the fuel rod is completed by girth welding the plug and rod joint at girth weld station 186, as per block 188 of FIG. 5, and then pressurizing the rod with helium at station 190 with a seal weld being made on the plug end, as per block 192 of FIG. 5. Prior to the girth welding operation, the rods were surged to break the synchronous operations into a second group. Once again after fabrication of the fuel rod is finished and before inspection begins, the rods are surged to break the synchronous operations into a third group. Then the rods are fed to an indexing transporter of the indexer system 160 where at a first station 194 in FIG. 8, as per block 196 of FIG. 5, a weld physical check is made. The weld bead is basically checked for diameter and discoloration in the weld area. Following next in sequence, as seen in FIG. 8, the rod is inspected ultrasonically and by x-ray florescence at respective stations 198 and 200, as per respective blocks 202 and 204, followed by checks for straightness and length at a station 206, as per block 208 of FIG. 5, and an inspection of the tube surface for scratches and marks at a station 210, as per block 212 of FIG. 5. After surface inspection, fuel rods are transferred downstream to a transition conveyor of the indexer system 160 where they are in turn fed to a gamma scanner station 214. As per block 216 of FIG. 5, the rods are scanned automatically for presence of internal components, pellet stack continuity, enrichment verification and plenum length. Results are entered into the traceability system. After a helium leak test at a station 218, as per block 220 of FIG. 5, the acceptable rods are sent to storage, as per block 222. Rods rejected from any of the inspection operations are identified and transferred to a processing area, as per block 224 of FIG. 5, where corrective action can be taken, after which the rod is returned to the rod fabrication operations or to a fuel rod salvage location, as per block 226 of FIG. 5. From the foregoing description, it will be understood that the automated system 10 is capable of achieving a high rate of production in a dedicated, continuous (paced) flow mode of operation by providing excess capacity at critical stages of the system. It integrates process operations, quality control inspection, improved materials flow, and accountability which results in a reduction of manufacturing cycle time. Also, it incorporates improved features for the containment of special nuclear materials, with enhanced ventilation to minimize the amount of airborne material and achieve reduced occupational exposure levels, not only during routine operations, but also to facilitate containment during maintenance. It is thought that the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof. |
claims | 1. A computed tomography scanner for performing a spiral scan, comprising:a rotatable X-ray emitter for generating a beam fan;an X-ray detector, positioned diametrically opposite to said rotatable X-ray emitter;an evaluation unit; andan X-ray filter, arranged downstream of the rotatable X-ray emitter, a position of the X-ray filter being correlated to a position of the X-ray detector and said X-ray filter being partly inserted into the beam fan only during operation for generating an unfiltered radiation component and, simultaneously, a filtered radiation component of the beam fan, wherein the radiation components have different X-ray spectra and wherein the evaluation unit is designed for separate evaluation of a measurement signal of the unfiltered radiation component and a measurement signal of the filtered radiation component, to obtain dual-energy images, wherein the X-ray filter is displaceably arranged in the beam fan and the X-ray filter is arranged in rotatable fashion. 2. The computed tomography scanner as claimed in claim 1, wherein the position of the X-ray filter is correlated to that of the X-ray detector such that, during the evaluation, there is an assignment of the portions on the X-ray detector the two filtered and unfiltered radiation components are incident. 3. The computed tomography scanner as claimed in claim 2, wherein the X-ray filter is made of tin, aluminum, copper, titanium or tungsten. 4. The computed tomography scanner as claimed in claim 2, wherein the X-ray filter covers a portion of the X-ray detector in a defined direction of extent of the X-ray detector. 5. The computed tomography scanner as claimed in claim 4, wherein the X-ray filter covers half of the X-ray detector in the defined direction of extent. 6. The computed tomography scanner as claimed in claim 1, wherein the X-ray filter is made of tin, aluminum, copper, titanium or tungsten. 7. The computed tomography scanner as claimed in claim 1, wherein the X-ray filter covers a portion of the X-ray detector in a defined direction of extent of the X-ray detector. 8. The computed tomography scanner as claimed in claim 7, wherein the X-ray filter covers half of the X-ray detector in the defined direction of extent. 9. The computed tomography scanner as claimed in claim 1, wherein the X-ray filter includes a plurality of different X-ray filters, displaceable into the beam fan. 10. The computed tomography scanner as claimed in claim 1, wherein the X-ray emitter comprises an emitter diaphragm, and wherein the X-ray filter is installed in the emitter diaphragm. 11. The computed tomography scanner as claimed in claim 1, wherein the computed tomography scanner is operateable in normal operation without the X-ray filter and in a dual-energy mode with the X-ray filter, and wherein a feed velocity of a patient couch relative to the X-ray emitter is reduced in the dual-energy mode in the case of a spiral scan. 12. A computed tomography scanner, for performing a spiral scan, comprising:a rotatable X-ray emitter for generating a beam fan;an X-ray detector, positioned diametrically opposite to said rotatable X-ray emitter;an evaluation unit; andan X-ray filter, arranged downstream of the rotatable X-ray emitter, a position of the X-ray filter being correlated to a position of the X-ray detector and said X-ray filter being partly inserted into the beam fan only during operation for generating an unfiltered and, simultaneously, a filtered radiation component of the beam fan, wherein the radiation components have different X-ray spectra, the evaluation unit is designed for separate evaluation of a measurement signal of the unfiltered radiation component and a measurement signal of the filtered radiation component, to obtain dual-energy images, the X-ray filter is displaceably arranged in the beam fan and the X-ray filter is displaceably arranged such that during a complete rotation of the X-ray emitter, the X-ray filter is adjustable at least between a cover position in which the X-ray filter completely covers the beam fan and a removed position in which the X-ray filter completely uncovers the beam fan. 13. A method for controlling a computed tomography scanner for performing a spiral scan, wherein the computed tomography scanner comprises a rotatable X-ray emitter for generating a beam fan, an X-ray detector positioned diametrically opposite to the rotatable X-ray emitter, and an evaluation unit, the method comprising:arranging an X-ray filter downstream of the X-ray emitter, a position of the X-ray filter being correlated to that of the X-ray detector;forming an unfiltered radiation component of the beam fan and, simultaneously, a filtered radiation component of the beam fan using the X-ray filter, the X-ray filter being only partly inserted into the beam fan, wherein the unfiltered and filtered radiation components have different X-ray spectra; andevaluating a measurement signal of the unfiltered radiation component, separate from an evaluation of a measurement signal of the filtered radiation component, to obtain dual-energy images, wherein the X-ray filter is displaceably arranged in the beam fan and the X-ray filter is arranged in rotatable fashion. |
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047770082 | abstract | In a steam generator for a pressurized water type nuclear reactor, for the purpose of isolating a water chamber in the steam generator from a coolant piping communicating with the water chamber, a plug is disposed in a nozzle section of the coolant piping, the plug is supported by a support arm having an angle adjusting screw and fixedly secured to a mount seat at a manhole communicating with the water chamber, and preferably, a cover is provided on the mount seat at the manhole. |
description | The present application is a U.S. national phase application under 35 U.S.C. § 371 of International Patent Application No. PCT/US17/22648 filed Mar. 16, 2017, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/311,540, filed Mar. 22, 2016, the entireties of which are hereby incorporated by reference. The present invention relates generally to an apparatus for storing and/or transporting radioactive materials, and specifically to a ventilated apparatus for storing and/or transporting radioactive materials that utilizes natural convection cooling. In the operation of nuclear reactors, it is customary to remove fuel assemblies after their energy has been depleted down to a predetermined level. Upon removal, the spent nuclear fuel (hereinafter, “SNF”) is still highly radioactive and produces considerable heat, requiring that great care be taken in its packaging, transporting, and storing. In order to protect the environment from radiation exposure, SNF is first placed in a hermetically sealed canister that creates a confinement boundary about the SNF. The loaded canister is then transported and stored in a large cylindrical container called a cask. Generally, a transfer cask is used to transport SNF from location to location while a storage cask is used to store SNF for a determined period of time. One type of storage cask is a ventilated vertical overpack (“VVO”). A VVO is a massive structure made principally from steel and concrete and is used to store a canister loaded with SNF. In using a VVO to store SNF, a canister loaded with SNF is placed in the cavity of the body of the VVO. Because the SNF is still producing a considerable amount of heat when it is placed in the VVO for storage, it is necessary that the cavity is vented so that this heat energy has a means to escape from the VVO cavity. It is also imperative that the VVO provide adequate radiation shielding and that the SNF not be directly exposed to the external environment. Thus, a need exists for a VVO system for the storage of radioactive materials that provides enhanced ventilation, reduces the likelihood of radiation exposure, and provides sufficient radiation blockage of both gamma and neutron radiation emanating from the high level radioactive waste. The present invention, in one aspect, is a ventilated apparatus having specially designed inlet ducts that allow a canister loaded with SNF (or other radioactive materials) to be positioned within the ventilated apparatus so that a bottom end of the canister is below a top of the inlet ducts while still preventing radiation from escaping through the inlet ducts. This aspect of the present invention allows the ventilated apparatus to be designed with a minimized height because the canister does not have to be supported in a raised position above the inlet ducts within the cavity of the ventilated apparatus. Thus, it is possible for the height of the cavity of the ventilated apparatus to be approximately equal to the height of the canister, with the addition of the necessary tolerances for thermal growth effects and to provide for an adequate ventilation space above the canister. In one embodiment, the invention can be ventilated apparatus for transporting and/or storing radioactive materials comprising: an overpack body having an outer surface and an inner surface forming an internal cavity about a longitudinal axis; a base enclosing a bottom end of the cavity; a lid enclosing a top end of the cavity; a plurality of outlet ducts, each of the outlet ducts forming an air outlet passageway from a top portion of the cavity to an external atmosphere; a bottom portion of the overpack body formed by a plurality of curved segments, each of the curved segments extending circumferentially from a first end wall having a convex portion to a second end wall having a concave portion; and the curved segments circumferentially surrounding the longitudinal axis and arranged in an intermeshing configuration such that for all adjacent curved segments: (1) the convex portion of the first end wall of one of the curved segments at least partially nests within the concave portion of the second end wall of an adjacent one of the curved segments; and (2) the convex portion of the first end wall of the one of the curved segments is spaced from the concave portion of the second end wall of the adjacent one of the curved segments, thereby forming an inlet duct forming an air inlet passageway from the external atmosphere to a bottom portion of the cavity. In another embodiment, the invention can be a ventilated apparatus for transporting and/or storing radioactive materials comprising: an overpack body having an outer surface and an inner surface forming an internal cavity about a longitudinal axis; a base enclosing a bottom end of the cavity; a lid enclosing a top end of the cavity; a plurality of outlet ducts, each of the outlet ducts forming an air outlet passageway from a top portion of the cavity to an external atmosphere; a bottom portion of the overpack body formed by a plurality of segments, each of the segments extending from a first end wall having a projection to a second end wall having a channel; and the segments circumferentially surrounding the longitudinal axis and arranged in an intermeshing and spaced-apart configuration such that the projections of the first end walls of the segments project into the channels of the second end walls of adjacent ones of the segments, thereby forming an inlet duct between adjacent ones of the segments that includes an air inlet passageway from the external atmosphere to a bottom portion of the cavity through which a line of sight does not exist from the cavity to the external atmosphere. In yet another aspect, the invention can be a ventilated apparatus for transporting and/or storing radioactive materials comprising: an overpack body having an outer surface, an inner surface forming an internal cavity about a longitudinal axis, and a top surface; a base enclosing a bottom end of the cavity; a plurality of air inlet ducts, each of the air inlet ducts forming an air inlet passageway from an external atmosphere to a bottom portion of the cavity; and a lid enclosing a top end of the cavity, the lid configured so that a plurality of air outlet passageways are at least partially defined by an interface between the lid and the top surface of the overpack body, each of the air outlet passageways extending from a top portion of the cavity to the external atmosphere. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto. Referring to FIGS. 1-3B concurrently, a ventilated apparatus 1000 is illustrated according to an embodiment of the present invention. The ventilated apparatus 1000 is a vertical, ventilated, dry, SNF storage system that is fully compatible with 100 ton and 125 ton transfer casks for spent fuel canister transfer and storage operations. The ventilated apparatus 1000 can, of course, be modified and/or designed to be compatible with any size or style of transfer cask. Moreover, while the ventilated apparatus 1000 is discussed herein as being used to store SNF, it is to be understood that the invention is not so limited and that, in certain circumstances, the ventilated apparatus 1000 can be used to transport SNF from location to location if desired. Moreover, the ventilated apparatus 1000 can be used in combination with any other type of high level radioactive waste. The ventilated apparatus 1000 may in certain embodiments be a ventilated vertical overpack. The ventilated apparatus 1000 is designed to accept a canister for storage at an Independent Spent Fuel Storage Installation (“ISFSI”). All canister types engineered for the dry storage of SNF can be stored in the ventilated apparatus 1000. Suitable canisters include multi-purpose canisters (“MPCs”) and, in certain instances, can include thermally conductive casks that are hermetically sealed for the dry storage of high level radioactive waste. Typically, such canisters comprise a honeycomb basket or other structure to accommodate a plurality of SNF rods in spaced relation. The ventilated apparatus 1000 comprises two major parts: (1) a dual-walled cylindrical overpack body 100 which comprises a set of inlet ducts 150 at or near its bottom extremity and an integrally welded baseplate 130; and (2) a removable top lid 500. In some embodiments, the removable top lid 500 may be equipped with at least one, or a plurality of, outlet ducts 550. However, as described herein below with reference to FIGS. 8A-8C, the invention is not to be so limited and the outlet ducts 550 may not be formed entirely by the lid 500 but may instead be formed by the interface of the lid 550 and the overpack body 100. The overpack body 100 forms an internal cavity 10 about a longitudinal axis A-A of sufficient height and diameter for housing an MPC 200 fully therein. The ventilated apparatus 1000 is designed so that the internal cavity 10 has a minimized height that corresponds to a height of the MPC 200 which is to be stored therein. Moreover, the cavity 10 preferably has a horizontal (i.e., transverse to the longitudinal axis A-A) cross-section that is sized to accommodate only a single MPC 200. The overpack body 100 extends from a bottom end 101 to a top end 102. The base plate 130 is connected to the bottom end 101 of the overpack body 100 so as to enclose the bottom end of the cavity 10. An annular plate or shear ring 140 is connected to the top end 102 of the overpack body 100. The shear ring 140 is a ring-like structure preferably formed from metal (i.e., steel) while the base plate 130 is a thick solid disk-like plate. The base plate 130 hermetically closes the bottom end 101 of the overpack body 100 (and the cavity 10) and forms a floor for the cavity 10 upon which a canister or MPC can rest as described herein below. The overpack body 100 comprises an inner shell 110 and an outer shell 120. The inner shell 110 has an inner surface 111 and an outer surface 112. The inner surface 111 of the inner shell 110 forms the inner surface of the overpack body 100 and defines or bounds the internal cavity 10 of the overpack body 100. The outer shell 120 has an inner surface 121 that faces the outer surface 112 of the inner shell 110 in a spaced apart manner and an outer surface 122 that forms the outer surface of the overpack body 100. In certain embodiments, each of the inner and outer shells 110, 120 is formed of metal, such as for example without limitation carbon steel or the like. The inner and outer shells 110, 120 are annularly spaced apart from one another. Specifically, the inner and outer shells 110, 120 are concentrically arranged so that a gap 105 exists between the outer surface 112 of the inner shell 110 and the inner surface 121 of the outer shell 120. The shear ring 140 mentioned above extends from a top end of the outer shell 120 inwardly towards the inner shell 110 and the longitudinal axis A-A. However, the shear ring 140 stops short of the inner shell 110 and thus it is connected only to the outer shell 120 and not also to the inner shell 110. Thus, a gap 141 remains between the shear ring 140 and the inner shell 110. By virtue of its geometry, in the exemplified embodiment the overpack body 100 is a rugged, heavy-walled cylindrical vessel. The main structural function of the overpack body is provided by its carbon steel components (the inner and outer shells 110, 120) while the main radiation shielding function is provided by an annular concrete mass 115 that fills in the gap 105 between the inner and outer shells 110, 120. The concrete mass 115 may comprise common cement, a chemically inert aggregate of a suitable density, and a specially selected hydrogen-rich additive. In addition, boron carbide powder may be added to the mix that forms the concrete mass 115 if it is desired to reduce neutron flux to the environment to infinitesimal levels. Boron carbide may be added in powder form or as chips of a metallic neutron absorber such as Metamic. Additional additives that may be included in the mix are vinyl, nylon, and similar hydrogen-rich polymers that are commercially available in granular form and that don't react with concrete or water and are stable at temperatures up to approximately 170° F. The polymeric additives in the concrete may be preferentially concentrated in the outer region of the annulus where the temperature of the concrete during service conditions is lower. The quantity of the hydrogenous additive may be varied to tailor the neutron blockage capability (effectiveness) required of the ventilated apparatus 1000. Both the hydrogen-rich compound and boron carbide are optional additives. As illustrated in FIG. 2B, the gap 105 between the inner and outer shells 110, 120 is filled with the concrete mass 115 (the concrete mass 115 is removed from FIG. 2A so that the details of the inlet ducts 150 are visible). The concrete mass 115 of the overpack body 100 is enclosed by the inner and outer shells 110, 120, the baseplate 130, and the top shear ring 140. Until the lid 500 is placed onto the top of the overpack body 100, the concrete mass 115 is exposed at the gap 141. A set of steel radial connector plates 114 are connected to and join the inner and outer shells 110, 120 together, thereby defining a fixed width annular space (i.e., the gap 105) between the inner and outer shells 120, 110 in which the concrete mass 115 is poured as best seen in FIGS. 2A, 2B and 9. In the exemplified embodiment the radial connector plates 114 are flat plate-type members oriented in the radial direction but they can be curved or non-radial in other embodiments. The material make-up of the concrete mass 115 between the inner and outer shells 120, 110 is specified to provide the necessary shielding properties (dry density) and compressive strength for the ventilated apparatus 1000. The principal function of the concrete mass 115 is to provide shielding against gamma and neutron radiation. However, the concrete mass 115 also helps enhance the performance of the ventilated apparatus 1000 in other respects as well. For example, the massive bulk of the concrete mass 115 imparts a large thermal inertia to the ventilated apparatus 1000, allowing it to moderate the rise in temperature of the ventilated apparatus 1000 under hypothetical conditions when all ventilation passages 150, 550 are assumed to be blocked. The case of a postulated fire accident at an ISFSI is another example where the high thermal inertia characteristics of the concrete mass 115 of the ventilated apparatus 1000 control the temperature of the MPC 200. Although the annular concrete mass 115 in the overpack body 100 is not a structural member, it does act as an elastic/plastic filler of the inter-shell space. While the overpack body 100 has a generally circular horizontal cross-section in the exemplified embodiment, the invention is not so limited. As used herein, the term “cylindrical” includes any type of prismatic tubular structure that forms a cavity therein. As such, the overpack body 100 can have a rectangular, circular, triangular, irregular or other polygonal horizontal cross-section. Additionally, the term “concentric” includes arrangements that are non-coaxial and the term “annular” includes varying width. As noted above, the overpack body 100 comprises a plurality of specially designed inlet ducts 150. The inlet ducts 150 are located at a bottom of the overpack body 100 and allow cool air to enter the cavity 10 of the ventilated apparatus 1000. The inlet ducts 150 form passageways that pass from the exterior atmosphere into the cavity 10 through the concrete mass 115 in the gap 105. Specifically, the inlet ducts 150 extend from an opening 123 in the outer shell 120 to an opening 113 in the inner shell 110. Each of the inlet ducts 150 is formed by the openings 113, 123 in the inner and outer shells 110, 120 and a lower metal inter-shell connector 155 (or a pair of lower metal inter-shell connectors 155 as described below) extending between one of the openings 113 in the inner shell 110 and one of the openings 123 in the outer shell 120. The inlet ducts 150 are positioned about the circumference of the overpack body 100 in a radially symmetric and spaced-apart arrangement. Thus, air from the external atmosphere can pass through the opening 123 in the outer shell 120 and into the inlet ducts 150 and then through the openings 113 in the inner shell 110 and into the internal cavity 10 of the overpack body 100. Once within the cavity 10, the air is warmed by the heat emanating from the MPC 200 stored in the cavity 10. This causes the air to flow upwardly within the cavity 10 towards the lid 500 and pass from a top portion of the cavity 10 through the outlet duct(s) 550 to the external atmosphere. The structure, arrangement and function of the inlet ducts 150 will be described in much greater detail below with reference to FIG. 4. In the exemplified embodiment, the MPC 200 rests directly on a top surface 131 of the base plate 130. In other embodiments, gussets may be included that connect the inner surface 111 of the inner shell 110 to the top surface 131 of the base plate 130, and the gussets may support the MPC 200. Such gussets may additionally act as guides for properly aligning the MPC 200 within the cavity 10 during loading and as spacers for maintaining the MPC 200 in the desired alignment within the cavity 10 during storage. When the MPC 200 is positioned in the cavity 10, an annular gap 11 exists between the outer surface of the MPC 200 and the inner surface 111 of the overpack body 100 (best seen in FIG. 3B). This provides a space for the air to flow around the MPC 200 as the cool air enters the cavity 10 through the air inlet ducts 150, becomes heated within the cavity 10, and then exits the cavity 10 through the air outlet ducts 550. The overpack body 100 also comprises a set of tubular shock absorbers 116 coupled to the inner surface 111 of the overpack body 100 (i.e., the inner surface 111 of the inner shell 110). The tubular shock absorbers 116 are only illustrated being located near the top of the cavity 10 but can additionally be located near the bottom of the cavity. The tubular shock absorbers 116 are arranged in a circumferentially spaced apart manner about the inner surface 111 of the overpack body 100. In the exemplified embodiment, the tubular shock absorbers 116 are hollow tube like structures but can be plate structures if desired. The tubular shock absorbers 116 serve as the designated locations of impact with the MPC lid 201 in case the ventilated apparatus 1000 tips over. The tubular shock absorbers 116 are designed to absorb kinetic energy to protect the MPC 200 during an impactive collision (such as a non-mechanistic tip-over scenario). Thus, in the exemplified embodiment, the tubular shock absorbers 116 are thin steel members sized to serve as impact attenuators by crushing (or buckling) against the solid MPC lid 201 during an impactive collision (such as a non-mechanistic tip-over scenario). The tubular shock absorbers 116 may be included to protect the fuel stored in the MPC 200 from experiencing large inertia loads in the unlikely event that the ventilated apparatus 1000 were to tip over. The tubular shock absorbers 116 are aligned with a hard location in the MPC 200, such as its closure lid 201 (see FIG. 3B), so that impact between the MPC 200 and the overpack body 100 is ameliorated by the tubular shock absorbers 116 during a tip over event. The overpack body 100 generally has a bottom portion 106 which is the portion that includes the air inlet ducts 150, a top portion 107 which is generally the portion that includes the tubular shock absorbers 116, and a middle portion 108 therebetween. In certain embodiments the air inlet ducts 150 may be approximately three feet tall, and thus the bottom portion 106 of the overpack body 100 may be approximately the bottom three feet of the overpack body 100. The MPC 200 is illustrated in the cavity 10 in FIG. 3B with the MPC 200 resting directly atop the top surface 131 of the base plate 130. As best seen in this figure, the set of tubular shock absorbers 116 are positioned so that a reference plane RP2-RP2 that is perpendicular to the longitudinal axis A-A of the overpack body 100 intersects both a lid 201 of the MPC 200 and the set of tubular shock absorbers 116. Referring now to FIGS. 2A, 2B, and 4 the overpack body 100 and specifically the structure thereof that forms the air inlet ducts 150 will be described in greater detail. The bottom portion 106 of the overpack body 100 is formed by a plurality of spaced apart segments or curved segments 170. Each segment 170 is a circumferential section of the bottom portion 106 of the overpack body 100 and thus it is curved because the overpack body 100 is cylindrical in the exemplified embodiment. Each of the segments 170 is spaced apart from an adjacent segment 170 and the air inlet ducts 150 are formed in the spaces between the adjacent segments 170. Each of the segments 170 extends circumferentially from a first end wall 171 having a convex portion or a projection 173 to a second end wall 172 having a concave portion or a channel 174. For each of the segments 170 that form the bottom portion 106 of the overpack body 100, the projection 173 and the channel 174 extend along the entire height of that segment 170. The segments 170 are also referred to herein as curved segments because they form the bottom portions of the curved inner and outer surfaces 111, 122 of the overpack body 100. The first end wall 171 of each of the segments 170 comprises a first shoulder 175 on a first side of the projection 173 and a second shoulder 176 on a second side of the projection 173. Specifically, the first shoulder 175 of each segment 170 is adjacent to (and may include a portion of) the inner shell 110 and the second shoulder 176 of each segment 170 is adjacent to (and may include a portion of) the outer shell 120. In the exemplified embodiment the first shoulder 175 of each segment 170 is formed partially by the concrete mass 115 and partially by the inner shell 110 whereas the second shoulder 176 of each segment 170 is formed partially by the concrete mass 115 and partially by the outer shell 120. In other embodiments, the first and second shoulders 175, 176 may be formed wholly by the inner and outer shells 110, 120, respectively, and the projection 173 may be formed by the concrete mass 115. The first and second shoulders 175, 176 extend generally radially. Furthermore, the first and second shoulders 175, 176 of each respective segment 170 are aligned on the same plane. The projection 173 is located between the first and second shoulders 175, 176 and protrudes circumferentially from the first and second shoulders 175, 176. The projection 173 of each segment 170 protrudes in the same circumferential direction. Specifically, in the exemplified embodiment each of the projections 173 protrudes from its respective segment 170 in a counter-clockwise direction. However, the invention is not to be so limited in all embodiments and in certain other embodiments each of the projections 173 may protrude from its respective segment 170 in a clockwise direction. However, in all embodiments the projections 173 should protrude in the same circumferential direction. The second end wall 172 of each of the segments 170 comprises a first channel wall 177 adjacent to the inner shell 110 and a second channel wall 178 adjacent to the outer shell 120. In the exemplified embodiment, the first channel wall 177 of each segment 170 is formed entirely by the inner shell 110 but may also be formed by a portion of the concrete mass 115. Furthermore, in the exemplified embodiment the second channel wall 178 of each segment 170 is formed entirely by the outer shell 120 but may also be formed by a portion of the concrete mass 115. Furthermore, the first and second channel walls 177, 178 of each respective segment 170 are aligned on the same plane. The channel 174 is defined between the first and second channel walls 177, 178. The segments 170 circumferentially surround the longitudinal axis A-A and are arranged in a nesting or intermeshing configuration. Specifically, the projection 173 of each segment 170 at least partially nests within the channel 174 of an adjacent segment 170 such that a plane that includes the longitudinal axis A-A will intersect the first end wall 171 (projection 173) of a first one of the segments 170 and a second end wall 172 (channel 174) of a second one of the segments 170 that is in a nested arrangement with the first one of the segments 170. Thus, the convex portion or the projection 173 of the first end wall 171 of a first one of the segments 170 at least partially nests within the concave portion or channel 174 of the second end wall 172 of an adjacent one of the segments 170 that is circumferentially adjacent to the first one of the segments 170. This is true for each of the adjacent segments 170. Thus, for each segment 170, an adjacent segment's projection 173 on a first side of the segment 170 nests within its channel 174 and the segment's projection 173 nests within an adjacent segment's channel 174 on the other side of the segment 170. In the exemplified embodiment, the channels 174 have a greater radius of curvature than the projections 173. For two of the segments 170 to be nested, a plane that includes the longitudinal axis A-A needs to exist that intersects the first end wall 171 of one of the nested segments 170 and the second end wall 172 of the other one of the nested segments 170. In the exemplified embodiment, a reference plane RP3 is illustrated (FIG. 4) that includes the longitudinal axis A-A and that intersects the first end wall 171 of a first one of the segments 170 and the second end wall 172 of an adjacent one of the segments 170. In fact, due to the spacing of the segments 170 in the exemplified embodiment, the reference plane RP3 will also intersect the first end wall 171 of one segment 170 and the second end wall 172 of an adjacent segment 170 that are circumferentially spaced 180° from the first one of the segments 170 and its adjacent segment 170. Furthermore, despite the nesting/intermeshing arrangement described above and shown in FIG. 4, the convex portion or projection 173 of the first end wall 171 of the first one of the segments 170 is spaced apart from the concave portion or channel 174 of the second end wall 172 of the adjacent one of the segments 170. Thus, the projection 173 of the first end wall 171 of the first one of the segments 170 nests within the channel 174 of the second end wall 172 of the adjacent one of the segments 170 without the first end wall 171 of the first one of the segments 170 contacting the second end wall 172 of the adjacent one of the segments 170. The spaces between the segments 170 form the air inlet ducts 150, which form air inlet passageways 160 from the external atmosphere to a bottom portion of the cavity 10 as discussed herein. More specifically, the lower inter-shell connectors 155 are disposed within the spaces between the adjacent segments 170. During manufacturing, the lower inter-shell connectors 155 are put into position first and then the concrete mass 115 is poured around the lower inter-shell connectors 155, although other manufacturing techniques are possible. The inter-shell connectors 155 are provided in pairs and covered with a roof 156 such that each pair of inter-shell connectors 155 defines one of the air inlet ducts 150 therebetween although each air inlet duct 150 could be formed by a singular member in other embodiments. Each of the inter-shell connectors 155 extends from the opening 123 in the outer shell 120 to the opening 113 in the inner shell 110 to form a passageway therebetween. Furthermore, one of the inter-shell connectors 155 is in contact with each of the first and second end walls 171, 172 of each of the segments 170. Thus, the inter-shell connectors 155 take on the shape of the first and second end walls 171, 172 of the segments 170. Each of the air inlet ducts 150 is formed between one of the inter-shell connectors 155 in contact with the first end wall 171 of a first segment 170 and one of the inter-shell connectors 155 in contact with the second end wall 172 of a second segment 170 that is adjacent to the first segment 170. In the exemplified embodiment the channels 174 of each of the segments 170 have an identical radius of curvature and the projections 173 of each of the segments 170 have an identical radius of curvature. Thus, in the exemplified embodiment each segment 170 is identical in size and shape to each other segment 170. Of course, this is not required in all embodiments and in alternative embodiments the segments 170 can be different sizes and shapes. Furthermore, in the exemplified embodiment each pair of adjacent segments 170 is spaced apart the same distance, thereby forming a plurality of the air inlet ducts 150 having the same dimensions. However, the invention is not to be so limited and the spacing between the segments 170 and hence also the dimensions/widths of the air inlet ducts 150 may vary in alternative embodiments. As can be seen in FIG. 4, each of the segments 170 is a singular uninterrupted member. Thus, there is no space or gap within any one of the individual segments 170. The only air passageways from the external atmosphere to the cavity 10 are between adjacent segments 170 and there are no air passageways formed within an individual segment 170. Rather, each of the segments 170 is an uninterrupted portion of the overpack body 100 that is formed of a solid material. Thus, a single segment 170 has a convex end wall (i.e., the first end wall 171) and a concave end wall (i.e., the second end wall 172) without any gaps or spaces being formed in the segment 170 between the first and second end walls 171, 172 in the circumferential direction. The only gaps are the air inlet ducts 150 which are formed between adjacent ones of the segments 170 and not within the segments 170. In the exemplified embodiment, there are twelve of the air inlet ducts 150 illustrated. However, due to the shape of the air inlet ducts 150 described in more detail below, it would be possible to include many more of the air inlet ducts 150 in other embodiments. Specifically, the air inlet ducts 150 can be positioned very close to one another and can possibly even be placed in a nesting or partially nesting arrangement. This would increase the number of openings in the outer shell 120 and the number of pathways available for the external air to enter into the cavity 10 to more effectively cool the MPC 200 stored therein and make the air inlet less sensitive to the direction of ambient wind. Each of the segments 170 also has a convex outer wall 179 and a concave inner wall 180. The convex outer wall 179 of each segment 170 forms a portion of the outer surface 122 of the overpack body 100. The concave inner wall 180 of each segment 170 forms a portion of the inner surface 111 of the overpack body 110. The convex outer walls 179 of the segments 170 lie in a first reference cylinder RC1. The concave inner walls 180 of the segments 170 lie in a second reference cylinder RC2 that is concentric to the first reference cylinder RC1. In the exemplified embodiment, each of the air inlet ducts 150 is a generally U-shaped structure defining generally U-shaped air inlet passageways 160 extending from the opening 123 in the outer shell 120 to the opening 113 in the inner shell 110. Thus, each of the air inlet ducts 150 (and also each of the air inlet passageways 160) has a convex side 151 and a concave side 152. The convex side 151 of each of the air inlet ducts 150 (and each of the air inlet passageways 160) faces the concave side 152 of an adjacent one of the air inlet ducts 150 (or air inlet passageways 160). Similarly, the concave side 152 of each of the air inlet ducts 150 (and each of the air inlet passageways 160) faces the convex side 151 of an adjacent one of the air inlet ducts 150 (or air inlet passageways 160). Thus, the air inlet ducts 150 may be positioned closer together than that illustrated in a nesting arrangement as mentioned above to increase the number of air inlet ducts 150 included in the apparatus 1000 in some embodiments. Furthermore, each of the air inlet passageways 160 comprises a first radial section 161 extending from the outer surface 122 of the overpack body 100 towards the cavity 10, a curved section 162 extending from the first radial section 161 towards the cavity 10, and a second radial section 163 extending from the curved section to the inner surface 111 of the overpack body 100. The first and second radial sections 161, 163 of each air inlet passageway 160 are aligned on the same radius of the first reference cylinder RC1 or on the same reference plane that includes the longitudinal axis A-A. In the exemplified embodiment, the overall shape of the air inlet passageways 160 are that of a horseshoe having ends that extend outwardly away from a longitudinal centerline of the horseshoe. Due to the U-shape of the air inlet passageways 160 of the air inlet ducts 150, a line of sight does not exist from the cavity 10 to the external atmosphere through the air inlet passageway 160 of the air inlet ducts 150. Specifically, viewing through the air inlet passageways 160 of the air inlet ducts 150 from the cavity 10, a person will not be able to see through to the external atmosphere, and vice versa. Although the U-shape is illustrated in the exemplified embodiment, other shapes are possible so long as a line of sight does not exist through the air inlet passageway 160 as noted herein. In some embodiments, the MPC 200 is positioned within the cavity 10 so that a first reference plane RP1 that is perpendicular to the longitudinal axis A-A of the overpack body 100 intersects both the MPC 200 and the inlet ducts 150. However, even though the MPC 200 is positioned atop the top surface 131 of the base plate 130 and thus is transversely aligned with the air inlet ducts 150, radiation (which travels in a straight line and cannot follow a tortuous path) cannot pass from the MPC 200 to the external environment. Rather, all radiation will contact the concrete mass 115 thereby preventing the radiation (both gamma and neutron radiation) from passing to the external environment. To maximize the cooling effect that the ventilating air stream has on the MPC 200 within the ventilated apparatus 1000, the hydraulic resistance in the air flow path is minimized to the extent possible. Towards that end, the ventilated apparatus 1000 comprises twelve inlet ducts 150 (shown in FIG. 4) in the exemplified embodiment. Of course, more or less inlet ducts 150 can be used as desired. Each inlet duct 150 is narrow and tall so as to minimize radiation streaming while optimizing the size of the airflow passages. The curved shape of the inlet ducts 150 also helps minimize hydraulic pressure loss. In one embodiment, each of the inlet ducts 150 has a height H1 and a width W1 (denoted in FIG. 3A) such that a ratio of the height to the width is at least 10:1, and more specifically at least 15:1, and still more specifically approximately 18:1. In one embodiment, the height is approximately 36 inches and the width is approximately 2 inches. The inlet ducts 150 permit the MPC 200 to be positioned directly atop the top surface 131 of the base plate 130 of the ventilated apparatus 1000 if desired, thus minimizing the overall height of the cavity 10 that is necessary to house the MPC 200. Naturally, the height of the overpack body 100 may then also be minimized. Minimizing the height of the overpack body 100 is an important ALARA-friendly design feature for those sites where the Egress Bays in their Fuel Buildings have low overhead openings in their roll-up doors. To this extent, the height of the storage cavity 10 in the ventilated apparatus 1000 is set equal to the height of the MPC 200 plus a fixed amount to account for thermal growth effects and to provide for adequate ventilation space above the MPC 200. As described herein, the MPC 200 can be placed directly on the base plate 130 such that the bottom region of the MPC 200 is level with the inlet ducts 150 because radiation emanating from the MPC 200 is not allowed to escape through the specially shaped inlet ducts 150 due to: (1) the inlet ducts 150 having a narrow width and being curved in shape; (2) the configuration of the inlet ducts 150 is such that that there is no clear line of sight from inside the cavity 10 to the exterior environment; and (3) there is enough steel and/or concrete in the path of any radiation emanating from the MPC 200 to de-energize it to acceptable levels. With the radiation streaming problem at the inlet ducts 150 solved, the top 102 of the overpack body 100 can be as little as ½″ higher than a top surface of the MPC 200. Additionally, positioning the MPC 200 in the cavity 10 so that the bottom surface of the MPC 200 is below the top of the opening 152 of the inlet ducts 150 ensures adequate MPC cooling during a “smart flood condition.” A “smart flood” is one that floods the cavity 10 so that the water level is just high enough to completely block airflow though the inlet ducts 150. In other words, the water level is just even with the top of the inlet ducts 150. Because the bottom surface of the MPC 200 is situated at a height that is below the top of the openings 123 of the inlet ducts 150, the bottom of the MPC 200 will be in contact with (i.e. submerged in) the water during a “smart flood” condition. Because the heat removal efficacy of water is over 100 times that of air, a wet bottom is all that is needed to effectively remove heat and keep the MPC 200 cool. Due to the height of the inlet ducts 150 being approximately 36 inches, the amount of water required to block the entire inlet duct 150 is a sufficient amount of water to cool the MPC 200. Thus, during a “smart flood condition” as described herein, the MPC cooling action effectively changes from ventilation air-cooling to evaporative water cooling. As noted above, the lid 500 is provided to close the open top end of the cavity 10. The lid 500 may also be provided with a structure that forms outlet ducts 550, thereby permitting air that is heated within the cavity 10 to exit the cavity 10 at a top portion of the cavity 10. The outlet ducts 550 may be formed into the lid 500 itself, or may be formed at the interface of the lid 500 and the overpack body 100. Either way, as heated air leaves the cavity 10 through the outlet ducts 550, cool air will continue to enter the cavity 10 at a bottom portion thereof through the air inlet ducts 150. This creates a natural convective flow of air to cool the MPC 200 within the cavity 10. Referring to FIGS. 1-3B and 5, the overpack lid 500 will be described in accordance with one embodiment of the present invention. The overpack lid 500 is a weldment of steel plates 510 filled with a concrete mass 515 that provides neutron and gamma attenuation to minimize skyshine. The lid 500 is secured to the top end 102 of the overpack body 100 by a plurality of bolts 501 that extend through the lid 500. The lid 500 may in other embodiments include a lid flange and the bolts 501 may extend through the lid flange for securing to the overpack body 100. In the exemplified embodiment, the bolts 501 connect to bolt receiving apertures 117 formed into the radial connector plates 114 as best shown in FIG. 9. Of course, alternative structures for securing the lid 500 to the overpack body 100 are possible in other embodiments. When secured to the overpack body 100, surface contact between the lid 500 and the overpack body 100 forms a lid-to-body interface. The lid 500 is preferably non-fixedly secured to the body 100 and encloses the top end of the cavity 10 formed by the overpack body 100. In the embodiment of FIGS. 1-3B and 5, the lid 500 comprises a radial ring plate or shear ring 505 welded to a bottom surface of the lid 500 which provides additional shielding against the laterally directed photons emanating from the MPC 200 and/or the annular space 11 formed between the outer surface of the MPC 200 and the inner surface 121 of the inner shell 120. The shear ring 505 also assists in locating the top lid 500 in a coaxial disposition along the longitudinal axis A-A of the ventilated apparatus 1000 through its interaction with the shear ring 140 of the overpack body 100. When the lid 500 is secured to the overpack body 100, the outer edge of the shear ring 505 of the lid 500 abuts the inner edge of the shear ring 140 of the overpack body 100. Specifically, the shear ring 505 of the lid 500 lies within the gap 141 atop the concrete mass 115 between the shear ring 140 of the overpack body 100 and the inner shell 110. Thus, the shear ring 505 also functions to prevent the lid 500 from sliding across the top surface of the overpack body 100 during a postulated tip-over event defined as a non-mechanistic event for the ventilated apparatus 1000. Specifically, the contact between the shear ring 505 of the lid 500 and the shear ring 140 of the overpack body 100 prevents any such sliding movement of the lid 500 relative to the overpack body 100. In this embodiment, the lid 500 comprises the plurality of outlet ducts 550 that allow heated air within the storage cavity 10 of the ventilated apparatus 1000 to escape. The outlet ducts 550 form passageways through the lid 500 that extend from openings 551 in the bottom surface 504 of the lid 500 to openings 552 in the peripheral surface 506 of the lid 500. While the outlet ducts 550 form L-shaped passageways in the exemplified embodiment, any other tortuous or curved path can be used so long as a clear line of sight does not exist from the external atmosphere to the ventilated apparatus 1000 into the cavity 10 through the outlet ducts 550. In the exemplified embodiment, the outlet ducts 550 are positioned about the circumference of the lid 500 in a radially symmetric and spaced-apart arrangement. The outlet ducts 550 terminate in openings 552 that are narrow in height but axi-symmetric in the circumferential extent. The narrow vertical dimensions of the outlet ducts 550 helps to efficiently block the leakage of radiation. It should be noted, however, that while the outlet ducts 550 are preferably located within the lid 500 in the exemplified embodiment, the outlet ducts 550 can be located within the overpack body 100 in alternative embodiments, for example at a top thereof, or at an interface of the lid 500 and the overpack body 100 as described herein with reference to FIGS. 8A-8C. As has been mentioned herein, the purpose of the inlet ducts 150 and the outlet ducts 550 is to facilitate the passive cooling of an MPC 200 located within the cavity 10 of the ventilated apparatus 1000 through natural convection/ventilation. The ventilated apparatus 1000 is free of forced cooling equipment, such as blowers and closed-loop cooling systems. Instead, the ventilated apparatus 1000 utilizes the natural phenomena of rising warmed air, i.e., the chimney effect, to effectuate the necessary circulation of air about the MPC 200 stored in the storage cavity 10. More specifically, the upward flowing air (which is heated from the MPC 200) within the annular space 11 that is formed between the inner surface 121 of the overpack body 100 and the outer surface of the MPC 200 draws cool ambient air into the storage cavity 10 through inlet ducts 150 by creating a siphoning effect at the inlet ducts 150. The rising warm air exits the cavity 10 through the outlet ducts 550 as heated air. The rate of air flow through the ventilated apparatus 1000 is governed by the quantity of heat produced in the MPC 200, the greater the heat generation rate, the greater the air upflow rate. FIG. 6 illustrates another embodiment of a lid 600 that can be used with the overpack body 100. The lid 600 is very similar to the lid 500 described herein. In that regard, the lid 600 has a shear ring 505 and the lid 600 defines a plurality of outlet ducts 650. The differences in structure of the lid 600 relative to the lid 500 can be readily seen by viewing FIGS. 5 and 6 concurrently. FIG. 7 illustrates yet another embodiment of a lid 700 that can be used with the overpack body 100. The lid 700 is similar to the lid 500 except as described herein. The first difference is that the lid 700 has a dome shape. A dome shaped lid such as the lid 700 may be used where the ventilated apparatus 1000 is required to withstand a very large downward load such as a falling missile. Further differences between the lid 700 and the lid 500 are also present in lid 800 illustrated in FIG. 8A and described below. Referring to FIGS. 8A-8C, the lid 800 and its cooperative structure when coupled to the overpack body 100 will be described. The lid 800 is similar to the lid 500 except that the outlet passageways of the outlet ducts are at least partially defined by the interface between the lid 800 and the overpack body 100 rather than being formed directly into the lid. Thus, the lid 800 does not define the entirety of the outlet ducts but they are formed once the lid 800 is coupled to the overpack body 100 as shown in FIG. 8C. Specifically, as seen in FIGS. 8A and 8B, the lid 800 comprises a bottom surface 804 and an opposite top surface 803. A plurality of spacers 806 are coupled to and extend from the bottom surface 804 of the lid 800. Furthermore, a shear ring 805 is coupled to the lid 800 via the spacers 806 such that the shear ring 805 is coupled directly to the terminal or distal ends of the spacers 806. Thus, the spacers 806 ensure that there is a space between the shear ring 805 and the bottom surface 804 of the lid 800. Referring to FIG. 8C the lid 800 is shown coupled to the overpack body 100 described earlier. As shown, when the lid 800 is coupled to the overpack body 100, the shear ring 805 of the lid 800 abuts against the shear ring 140 of the overpack body 100 similar to that which was described with reference to FIGS. 1-4. Furthermore, the spacers 806 rest directly atop the shear ring 140 of the overpack body 100. Thus, the spacers 806 ensure that a space exists between the bottom surface 804 of the lid 800 and the shear ring 140 of the overpack body 100. This space forms a portion of the outlet ducts 850. As shown in FIG. 8C, although a portion of the outlet ducts 850 appear to be formed between the bottom surface 804 of the lid 800 and the shear ring 805 of the lid 800, a portion of the outlet ducts 850 is also formed between the bottom surface 804 of the lid 800 and the top surface 102 of the overpack body 100 (or the shear ring 140 of the overpack body 100). Specifically, in the exemplified embodiment each of the air outlet passageways comprises an outlet portion 810 that is formed by the top surface 102 of the overpack body 100 and a perimeter portion 808 of the bottom surface 804 of the lid 800. Thus, in this embodiment the outlet ducts 850 are at least partially defined by an interface between the lid 800 and the overpack body 100. Each of the air outlet ducts 850 forms an air outlet passageway from the top portion of the cavity 10 to the external atmosphere as with the previously described embodiments. FIG. 10 is a close-up view of a portion of the bottom of the overpack body 100 in accordance with an alternative embodiment. In some embodiments, it may be desired to restrain the ventilated apparatus 1000 from movement on the storage pad at the ISFSI. Thus, in this embodiment the base plate 130 has been extended so as to form a flange 132 that protrudes from the outer surface 122 of the overpack body 100. The flange 132 has a plurality of apertures 133 therethrough, each of which operates as an anchor location through which an anchor 139 (screw, bolt, etc.) can be inserted to secure the overpack body 100 to a storage pad or other desired surface. The anchor locations are reinforced by gussets 134 that extend from the outer surface 122 of the overpack body 100 to the upper surface 135 of the flange 132. The radial dimension of the flange 132 (i.e., the distance that it extends from the outer surface 122 of the overpack body 100) is preferably minimized to minimize movement of the flange 132 during a cask uplift or tipping event and to facilitate its handling by a vertical cask transporter without significantly increasing the overall width dimension of the overpack body 100. While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. |
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claims | 1. A lithographic exposure device comprising a reflective optical element and a hydrocarbon getter positioned in sufficient proximity to the reflective optical element to reduce carbon deposition thereon; and a controller for controlling an energy beam to maintain the amount of hydrocarbons in the system at a predetermined level. 2. The device according to claim 1, wherein the hydrocarbon getter comprises a substrate and a high energy source positioned to direct the energy beam, having sufficient energy to crack the hydrocarbons and form carbon, on the substrate. 3. The device according to claim 2, which is an extreme ultraviolet (EUV) lithography exposure device comprising a primary EUV source and at least one reflective optical element for soft X-ray or extreme ultraviolet wavelength (EUV) range radiation, wherein the hydrocarbon getter energy source is capable of directing a beam having an energy at least as great as that generated by the primary EUV source. 4. The device according to claim 3, wherein the energy source is an electron gun or a separate EUV source. 5. The device according to claim 4, wherein the substrate comprises a metal coating. 6. The device according to claim 5, wherein the substrate comprises ruthenium (Ru)-coated glass. 7. The device according to claim 4, wherein the energy source is an electron gun. 8. The device according to claim 3, wherein the substrate comprises a quartz crystal thickness monitor. 9. The device according to claim 8, further comprising: a residual gas analyzer for determining the hydrocarbon level in the device. 10. The device according to claim 9, wherein the controller controls the beam current in response to a thickness of carbon deposited on the substrate. 11. The device according to claim 1, wherein the hydrocarbon getter is positioned at a distance of 1 cm to 10 cm from the reflective optical element. 12. An extreme ultraviolet (EUV) lithography exposure device comprising:a primary EUV source;a reflective optical element for the soft X-ray or EUV wavelength range radiation;a hydrocarbon getter comprising a substrate and an electron gun or a separate EUV source positioned to direct an energy beam at the substrate;a residual gas analyzer for determining the amount of hydrocarbons in the device; anda controller for controlling the beam current to maintain the amount of hydrocarbons in the system at a predetermined level. 13. The device according to claim 12, wherein the substrate comprises a quartz crystal thickness monitor. 14. The device according to claim 12, wherein the controller controls the beam current in response to a thickness of carbon deposited on the substrate. 15. A method of reducing carbon deposition on a reflective element of a lithographic exposure device, the method comprising positioning a hydrocarbon getter in the lithographic exposure device in sufficient proximity to the reflective element to reduce carbon deposition thereon; and controlling the strength of an enemy beam in response to the measured thickness of the deposited carbon to maintain the amount of hydrocarbons in the device at a predetermined level. 16. The method according to claim 15, wherein the hydrocarbon getter comprises a substrate and a high energy source positioned to impinge the energy beam on the substrate. 17. The method according to claim 16, wherein:the lithographic exposure device comprises a primary extreme ultraviolet (EUV) source and at least one reflective optical element for the soft X-ray or EUV wavelength radiation range; andthe energy source comprises an electron gun or a separate EUV source. 18. The method according to claim 15, comprising:positioning the hydrocarbon getter at a distance of 1 cm to 10 cm from the reflective element. 19. The method according to claim 18, wherein the substrate comprises a quartz crystal thickness monitor. 20. The method according to claim 19, further comprising:determining the amount of hydrocarbons in the device;measuring the thickness of carbon deposited on the substrate. |
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abstract | An anti-scatter X-ray raster provides suppression of secondary scattered Compton radiation thus improving image contrast. The anti-scatter X-ray raster comprises a plurality of tubular channels made of an X-ray absorbing material. The tubular channels are spliced together to form a cellular structure. The largest cross size (d) of a singe channel its length (H) meet a relationship 2d/H greater than xcex8c, where xcex8c is a critical angle of total external reflection of X-rays from the material forming the walls of the tubular channels. The cross-section of the tubular channels need not be circular but may be, for example triangular or hexagonal. In a non-focused raster embodiment all of the longitudinal axis of the channels are parallel. In focused embodiments, the longitudinal axis of the channels are radially angled such that if extended they would meet at the X-ray source point. |
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summary | ||
claims | 1. A device for connecting a first depressurization vessel to a second depressurization vessel, the device comprising:a communication hole comprising:a first opening which is connected to the first depressurization vessel, anda second opening which is connected to the second depressurization vessel, the first opening and the second opening being, respectively, at opposite ends of the communication hole such that extreme ultraviolet radiation passes in a radiation direction from the first opening to the second opening;a gas inlet through which a gas from a gas supply unit flows into the communication hole in a direction perpendicular to the radiation direction of the extreme ultraviolet radiation; anda first gas outlet which is opposed to the gas inlet such that the gas is exhausted from the gas outlet by a first gas exhaust unit;at least one second gas outlet provided on a side of the second depressurization vessel with respect to the first gas outlet such that the gas supplied through the gas inlet is exhausted by a second gas exhaust unit, wherein the second gas outlet is arranged not opposed to the gas inlet. 2. The device of claim 1, wherein the gasdoes not absorb the extreme ultraviolet radiation. 3. The device of claim 2, further comprising:at least one third gas outlet provided on a side of the first depressurization vessel with respect to the first gas outlet such that the gas supplied through the gas inlet is exhausted by a third gas exhaust unit, wherein the third gas outlet is arranged not opposed to the gas inlet. 4. The device according to claim 2, wherein a pressure inside the first depressurization vessel is higher than a pressure inside the second depressurization vessel. 5. The device according to claim 1, wherein an opening of the gas inlet and an opening of the first gas outlet each has a rectangular shape of about 5 mm by about 5 mm. 6. An exposure equipment comprising:a first depressurization vessel that comprises a component for radiating extreme ultraviolet radiation and a first opening through which the extreme ultraviolet radiation passes;a second depressurization vessel that comprises a second opening for receiving the extreme ultraviolet radiation passed from the first depressurization vessel; anda connection device which connects the first depressurization vessel to the second depressurization vessel, the connection device comprising:a communication hole comprising two opening ends disposed on opposite sides, respectively, of the communication hole, wherein the first opening and the second opening are opposed to each other and are connected to respective ones of the two opening ends;a gas inlet through which a gas, which does not absorb the extreme ultraviolet radiation, flows in a direction perpendicular to a passing direction of the extreme ultraviolet radiation; anda first gas outlet which is provided at a position opposed to the gas inlet so as to remove the gas from the communication hole;at least one second gas outlet which is provided between the second depressurization vessel and the first gas outlet so as to remove the gas from the communication hole; andat least one third gas outlet which is provided between the first depressurization vessel and the first gas outlet so as to remove the gas from the communication hole;a gas supply unit connected to the gas inlet so as to supply the gas to the connection device; anda gas exhaust unit comprising:a first gas exhaust unit connected to the first gas outlet so as to remove the gas;a second gas exhaust unit connected to one of the at least one second gas outlet so as to remove the gas; anda third gas exhaust unit connected to one of the at least one third gas outlet so as to remove the gas. |
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042010926 | abstract | A method of detecting and monitoring leaks in the piping of a nuclear reactor senses the acoustic energy from the leak and analyzes its frequency spectrum versus acoustic amplitude. A choke flow condition will exist where the leak flows at sonic velocity; here the acoustic energy is directly proportional to the area of the crack producing the leak. This is utilized to provide an indication of crack enlargement. |
abstract | A filter is provided which includes channels for circulation of coolant fluid through the filter, at least one channel extending along a channel centerline and includes an upstream section, a downstream section and an intermediate section extending between the upstream section and the downstream section and being enlarged relative to the upstream section and the downstream section. The filter also includes at least one separating member defining inside the intermediate section of the at least one channel an annular passage whose axis is substantially coaxial to the channel centerline in the intermediate section. |
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description | This patent application is related to previous patents by the inventor related to the disposal of nuclear waste in deep underground formations. These patents are: U.S. Pat. No. 5,850,614; U.S. Pat. No. 6,238,138; and U.S. Pat. No. 8,933,289; the disclosures of which are all incorporated herein by reference in their entirety. The present invention relates generally to disposing of nuclear waste and more particularly, to: (a) the operations of nuclear waste disposal; and (b) utilization of specialized capsules or containers for nuclear waste which may be sequestered in lateral wellbores drilled into deep geologic formations, such that, the nuclear waste is disposed of safely, efficiently, economically and in addition, if required, may be retrieved for various reasons. A portion of the disclosure of this patent application may contain material that is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever. Certain marks referenced herein may be common law or registered trademarks of third parties affiliated or unaffiliated with the applicant or the assignee. Use of these marks is by way of example and should not be construed as descriptive or to limit the scope of this invention to material associated only with such marks. Today there is a massive quantity of nuclear waste accumulating across the world. In the US alone there are more than 70,000 metric tons (MT) of high-level solid waste (HLW) being stored in cooling pools and in concrete casks on the surface. This surface operation is very costly typically costing hundreds of millions of dollars annually. The HLW is generally called spent nuclear fuel (SNF) and consists of thousands of nuclear fuel assemblies which have been removed from operating nuclear power plants. These fuel assemblies are highly radioactive and also thermally active and continue to generate sensible heat which must be safely removed by maintaining these assemblies in cooling tanks at the onsite surface storage site. There are approximately 80,000 individual fuel assemblies being stored today in the US and about 15,000 MT being added annually. There is a significant need for new mechanisms and processes to safely get rid of the surface storage of this radioactive waste and to sequester this SNF waste in a safe manner. In this application HLW and SNF are used interchangeably to describe the solid nuclear waste product. In this application the word capsule and canister may be used interchangeably with the same meaning; and HLW and SNF describing nuclear waste may also be used interchangeably herein. Current scientific knowledge teaches that the conversion of nuclear waste to an acceptable waste form requires either, (a) that the wastes be separated from the other constituents and processed separately, or (b) that the wastes together with the other constituents be processed together. Both processes present a variety of technical challenges. Due to the radioactivity and toxicity of the wastes, separation can be both hazardous, expensive and prone to human-induced accidental problems. To date, and based on the prior art, in order to provide a satisfactory and economical final disposal of these wastes, it is desirable that the wastes be processed into a final form without the hazardous and expensive step of removing the other constituents. It has been understood that the waste in this final form prevents removal of the fissile constituents of the wastes and further immobilizes the waste to prevent degradation and transport of the waste by environmental mechanisms. Several methods for providing an acceptable final form for waste are known in the art, including: (a) Vitrification to produce borosilicate glasses having waste constituents bound within the glasses has been shown as an effective method for treatment of low volumes of HLW. In the vitrification process, wastes are mixed with glass-forming additives and converted into an amorphous glassy form by high temperature melting and cooling. There are several inherent technical drawbacks of vitrification. A further drawback of vitrification arises due to the low solubility of many of the waste components of interest in glass which prohibits large concentrations of the waste components in the final glass form. This low solubility greatly increases the required volume of the final waste form for a given volume of radioactive waste components of interest, thus unfortunately the waste volume “grows.” This makes the overall nuclear waste product even larger than the original thus requiring more storage and costs. (b) Ceramification produces another form of nuclear waste. It can be accomplished by the incorporation of waste components of interest into a synthetic rock (synroc) which is a ceramic material. The synroc process has been fully developed and as commercialized in Australia (ANSTO) produces a crystalline final waste form and involves several complex expensive steps involving high temperatures and pressures utilized to successfully create a suitable final waste form. The cost associated with these two primary methodologies is prohibitive. Published information from the US Hanford Nuclear facility which is designed for vitrification operations has a projected cost level of $16 Billion. Published information from the ANSTO facility which is designed for ceramification operations has a projected cost of hundreds of millions of dollars. Commercial revenues are expected to pay for development. Both processes listed herein (e.g., vitrification and/or ceramification) increases a volume of waste product to be stored. Thus, use of these processes may be counter-intuitive with a goal of minimizing an amount of nuclear waste. That is, use of these processes creates even more nuclear waste that needs to be safely handled and stored. Based on the inherent shortcomings of the prior art, there exists a critical need for an effective, economical method for developing and utilizing an acceptable nuclear waste process for nuclear waste products; a process that precludes the need for all the expensive, time-consuming and dangerous intermediate operations that are currently being used or contemplated to render the nuclear waste in a form that eventually, still has to be buried in deep underground repositories. An approach is needed that minimizes these intermediate steps. To solve the above-described problems, the present invention provides a system and method to dispose of the nuclear waste currently accumulating on the surface. The novel approach as taught in the application provides a methodology wherein the waste disposal operations go directly from the existing fuel assembly rod cooling ponds to the underground disposal repository with minimal additional effort and without the afore-listed intermediary steps of vitrification and ceramification. It is to these ends that the present invention has been developed. To minimize the limitations in the prior art, and to minimize other limitations that will be apparent upon reading and understanding the present specification, the present invention describes systems and methods for storage of nuclear waste into closed and deep geological formations, using waste-capsules and largely intact bundles of fuels rods. The present invention is concerned with disposing of nuclear waste and, more specifically, to a method and system of disposing of encapsulated nuclear waste in deep underground closed rock formations using multilateral horizontal boreholes connected to the surface by a vertical wellbore. More specifically, the invention describes methods and systems in which a novel capsule system and internment methodology are illustrated to provide a safe long-term nuclear waste repository. A primary object of the present invention is to provide a method of disposing of nuclear waste in deep underground rock formations. An additional object of the present invention is to provide a method of disposing of nuclear waste in underground rock formations which will provide protection in case of rupturing or leaking of a canister in which such waste may be stored. As noted, both processes listed herein (e.g., vitrification and/or ceramification) increases the volume of waste product to be stored. Thus, use of these processes may be counter-intuitive with a goal of minimizing an amount of nuclear waste. That is, use of these processes creates even more nuclear waste that needs to be safely handled and stored. It is possible to provide a method of disposing of nuclear waste in underground rock formations which will bury the waste in horizontally extending lateral boreholes positioned well below the earth's surface and thus very remote from the ecosphere. In some embodiments, providing a waste-capsule in which the nuclear waste is further protected by a series of engineering and natural barriers may be utilized. It is possible to provide a method of disposing of nuclear waste in deep closed underground rock formations wherein the design of the capsule provides several novel features which allow: (a) personnel safety during surface transport of HLW; (b) personnel safety on the surface during drilling and disposal working operations; (c) economic and operational efficiencies in post-processing after waste accumulation at the power plants and prior to preparation of SNF for sequestering underground; (d) long term corrosion resistance while stored underground; (e) long term radionuclide protection to the environment; (f) retrievability of the capsule and thus the HLW after emplacement even under severe adverse conditions; (g) an additional object of the present invention is to provide a method in which the capsules can be disposed underground in a manner such that the waste generated heat load is optimally distributed such that the process remains stable over time and the heat load is below permissible limits; and/or (h) an implementation of non-waste-bearing inline spacers to allow control of generated heat load in the waste repository. A method of disposing nuclear waste in underground rock formations is disclosed by the present invention. The method includes a step of selecting an area of land having a rock formation positioned there below. The rock formation must be of a depth able to prevent radioactive material placed therein from reaching the surface over geologic times and must be at least a predetermined distance from active water sources. In some embodiments, the method may further include drilling a vertical wellbore from about 5,000 feet to about 30,000 feet deep from the surface of the selected area which extends into the underground rock formation. In some embodiments, a diameter of the vertical wellbore may be between about 10 inches and about 36 inches, plus or minus one inch. The selected geologic formations should also be structurally closed and comprise sufficient distinct geologic layers of specific petrophysical properties such that the repository is stratigraphically impermeable to fluid migration. In some embodiments, at least one primary horizontal lateral wellbore of length varying from 500 feet to 20,000 feet, may be drilled out from the vertical wellbore whereby the surface of the horizontal lateral is defined by the underground rock formation. In some embodiments, a diameter of the lateral well bores may vary from about 5 inches to about 30 inches, plus or minus one inch. Secondary laterals can be drilled off the initial primary lateral as needed to increase the total volumetric capacity of the disposal system. A steel casing is placed within the horizontal lateral and cemented in place by circulating cement in the annular space between the steel casing and the wall of the wellbore. Nuclear waste to be stored within the lateral is placed in a canister or capsule and the encapsulated nuclear waste is positioned within the primary horizontal lateral as described herein. The capsules are then sealed in place with appropriate means. In some embodiments, a method may provide an operational method for fabricating at least one nuclear waste capsule. In this operational method the recommended tasks involved provide a more efficient methodology to allow safer, more economical and long lasting disposal of the nuclear waste in the deep underground repositories. In some embodiments, a very significant existing consideration be addressed in long-term nuclear waste disposal process. It is the eventual degradation of the physical integrity of the well bore system components. Some mechanisms are needed to minimize the degradation. A long-lived technology system is required to guarantee within technical certainty that the HLW can be contained adjacent and within the repository zone. In some embodiments, a means may be utilized that may provide for very long-lived protection from degradation and migration of material away from the nuclear waste material. Stratigraphic and current structural geological analysis of underground oil formations which have historically produced heavy oil and other hydrocarbons indicate that tar-like deposits have existed for millions of years and have remained essentially unchanged and intact over time. In many cases the tar-like deposits actually formed an impermeable seal that prevented fluid flow across the rock matrix due to physical and chemical changes in the rock media. Bitumen-like products and some petroleum-based products possess the qualities that make them capable of being utilized for low temperature sealing situations in the disposal of nuclear wastes. Other more temperature resistant chemical products are needed for higher temperature situations. In many oil reservoirs, geologists have defined so-called “marker” beds of tar or high viscosity bitumen which are millions of years old. This geologic phenomenon illustrates the chemical stability of the hydrocarbon-based material over very long time periods, usually millions of years. This chemical stability of the tar-like material allows a selection of natural or similar synthetic hydrocarbons or hydrocarbon derivatives based materials as the long-lived high-temperature resistant layer used to surround the high-level waste material inside the capsules. This application provides for the use of such a medium in the protection of the HLW material. The current invention teaches an improved engineered barrier system implemented in this application with the longest duration barrier, the protective medium at the inner-most layer of protection. In a naturally occurring degradation process, the degradation beginning at the outermost layer in contact with the earth continues inwards into the central core of the system. The outer protective layers, outer cement, outer steel pipe, inner cement, inner steel pipe, in this application all will degrade over varying time horizons. The inner-most tar-like medium has been historically demonstrated in the geological record, to be an effective fluid and migration barrier for millions of years. In numerical terms the cement and steel may degrade in 2,000 to 10,000 years, however the tar enclosed central core shall be protected for hundreds of thousands of years. The foregoing and other objects, advantages and characterizing features will become apparent from the following description of certain illustrative embodiments of the invention. The novel features which are considered characteristic for the invention are set forth in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawings. Attention is called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims. These and other advantages and features of the present invention are described herein with specificity so as to make the present invention understandable to one of ordinary skill in the art, both with respect to how to practice the present invention and how to make the present invention. 10 drilling-rig 10 10a nuclear power plant 10a 10b surface-storage-locations 10b 15 vertical-wellbore 15 20 primary lateral wellbore 20 20a secondary lateral wellbore 20a 25 waste-capsule 25 (for HLW or spent nuclear fuel) 30a cement 30a (between inner and outer pipes) 30b cement 30b (between outer pipe and formation) 31 outer pipe 31 32 initial lateral borehole 32 33 inner pipe 33 33a mechanical plug 33a 34 carrier tube 34 35 protective-medium 35 36 fuel rod assembly 36 36a fuel-rods-bundle 36a 36b dividing-plane 36b (for disassembly of fuel rod assembly core) 36c nuclear waste core 36c 37a centralizer 37a (for inner pipe) 37b centralizer 37b (for outer pipe) 38 deep-geological-formation 38 (for nuclear waste disposal) 39 support 39 (for fuel nuclear waste core) 40 pipe-coupling 40 42 valve element 42 44 non-waste-bearing-spacer 44 301 step of minimal to no preprocessing prior to storage 301 302 step of vitrification preprocessing prior to storage 302 303 step of ceramification preprocessing prior to storage 303 800 method of handling nuclear waste 800 801 status of fuel rod assembly in surface storage 801 803 step of receiving fuel rod assembly from surface storage 803 805 step of disassembling fuel rod assembly 805 807 step of dissembling using dividing-planes 807 809 step of inserting nuclear waste core into carrier tube 809 811 step of supporting nuclear waste core 811 813 step of injecting protective-medium 813 815 step of sealing carrier tube 815 817 step of installing spacers between carrier tubes 817 819 step of joining carrier tubes via pipe couplings 819 821 step of inserting sealed carrier tubes into inner pipes into boreholes 821 823 step of finishing inserting sealed carrier tubes into inner pipes 823 825 step of drilling boreholes 825 827 step of loading outer pipes into boreholes 827 829 step of injecting cement 829 831 step of loading inner pipes into outer pipes 831 833 step of injecting cement 833 835 step of sealing boreholes 835 In the following discussion that addresses a number of embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part thereof, where depictions are made, by way of illustration, of specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the invention. In this patent application the words “tube” and “pipe” may be used interchangeably and refer to cylindrical elements implemented in the design and installation processes. In this patent application the word “capsule,” “carrier tube,” and “canister” may be used interchangeably with the same meaning; and “HLW” and “SNF” describing nuclear waste may also be used interchangeably herein. FIG. 1 may illustrate an inclusive overview of the nuclear waste disposal system and/or process. A surface drilling-rig 10 may be apparatus that drills vertical-wellbore 15, primary lateral wellbore 20, and/or secondary lateral wellbore 20a; and into which the waste-capsule(s) 25 may be disposed of in deep-geological-formation 38. In some embodiments, deepgeological-formation 38 may be located substantially from about 5,000 feet to about 30,000 feet below a surface, plus or minus 1,000 feet. In some embodiments, deep-geological-formation 38 may have geologic properties that make storing nuclear materials relatively safe. For example, and without limiting the scope of the present invention, in some embodiments, deep-geological-formation 38 may have one or more of the following geologic properties: structural closure, stratigraphically varied, low porosity, low permeability, low water saturation, and reasonable clay content. For example, and without limiting the scope of the present invention, in some embodiments, primary lateral wellbore 20 (e.g., which may be an initial lateral borehole 32) may be located a predetermined depth of at least 10,000 feet below the surface. In some embodiments, waste-capsule 25 may store (e.g., contain) HLW (high-level solid waste) and/or SNF (spent nuclear fuel). Associated usually, but normally at distant remote locations, may be nuclear power plant 10a; and/or surface-storage-locations 10b for nuclear waste storage. In some embodiments, drilling-rig 10 may be a typical drilling rig as used in the oil-well drilling industry but with several updated modifications and features to allow safe handling of the radioactive waste (such as, HLW and/or SNF). FIG. 2 may illustrate primary lateral wellbore 20 relationship with respect to vertical-wellbore 15. In some embodiments, while at least some portions of vertical-wellbore 15 may be substantially vertical with respect to a surface of the earth, at least some portions of primary lateral wellbore 20 may be substantially horizontal. In some embodiments, one or more primary lateral wellbores 20 may emanate (e.g., derive) from vertical-wellbore 15. In some embodiments, one or more secondary lateral wellbores 20a may emanate (e.g., derive) from primary lateral wellbores 20. In some embodiments, one or more waste-capsules 25 may be located, placed, and/or stored in one or more of primary lateral wellbores 20, secondary lateral wellbores 20a, and/or vertical-wellbores 15. In some embodiments, drilling-rig 10 may be used to form one or more of vertical-wellbores 15, primary lateral wellbores 20, and/or secondary lateral wellbores 20a. In some embodiments, one or more of vertical-wellbores 15, primary lateral wellbores 20, and/or secondary lateral wellbores 20a may have predetermined diameters. For example, and without limiting the scope of the present invention, in some embodiments such wellbore diameters may be selected from the range of substantially six inches to substantially 48 inches, plus or minus one inch. In some embodiments, one or more of vertical-wellbores 15, primary lateral wellbores 20, and/or secondary lateral wellbores 20a may have predetermined lengths. For example, and without limiting the scope of the present invention, in some embodiments such lengths may be selected from the range of substantially five hundred feet to substantially twenty five thousand feet. FIG. 3 illustrates two means for preprocessing the SNF for eventual disposal according embodiments of this invention. Some embodiments of the present invention may be focused on utilizing the least number of intermediary steps (e.g., preprocessing steps) in moving from nuclear power plant 10a to deep-geological-formation 38. Step 301 may be an embodiment for waste disposal as taught by this application, with minimal to no preprocessing steps. Step 302 may illustrates the vitrification pre-process in which the SNF is changed to glass like materials and then subsequently stored according to an embodiment of this invention. Step 303 may show the ceramification pre-process in which a synthetic ceramic rock “synroc” may be produced that may then be subsequently stored according to embodiments of this invention. As shown in FIG. 3, in some embodiments, waste-capsule 25 may comprise two opposing terminal ends. In some embodiments, waste-capsule 25 may be an elongate member. In some embodiments, waste-capsule 25 may be a substantially cylindrical member. In some embodiments, waste-capsule 25 may be rigid to semi-rigid. FIG. 4 may illustrate a transverse-width cross-section of a generic nuclear fuel rod assembly 36 as normally used in nuclear power plant 10a. In practice, fuel rod assembly 36 may be constructed by piecing together two or more sub-assemblies of fuel-rods-bundles 36a to form an integral sub-assembly unit in which physical division-planes 36b may be formed demarcated. For example, and without limiting the scope of the present invention, a given fuel rod assembly 36 may be formed from four such fuel-rods-bundles 36a, as shown in FIG. 4. Some embodiments of the present invention may utilize this inherent demarcation feature of fuel rod assemblies 36 to fashion a new and efficient means to safely solve waste disposal problems for SNF and/or HLW. A given fuel rod assembly 36 may be a complex apparatus comprising: metal fuel guides, channel fasteners, tie plates, expansion springs, locking tabs, metal channels, control rods, fuel rods, spacers, core plate assembly, lower tie plates, fuel support pieces, fuel pellets, end plugs, channel spacers, plenum springs, and the like. FIG. 5 may illustrate an efficient operational sequence of tasks going from a complete fuel rod assembly 36 to a set of broken apart or otherwise separated fuel-rods-bundles 36a. FIG. 8 may illustrate a flow chart addressing such steps. In some embodiments, fuel rod assembly 36 may be disassembled by separating these subassembly elements of fuel-rods-bundles 36a at division-planes 36b as shown in steps 805 and 807 in FIG. 8. FIG. 5 may be a graphical depiction of steps 805 and 807 in FIG. 8. In some embodiments, a given fuel-rods-bundle 36a once separated from other fuel-rods-bundle 36a, may be known as a “nuclear-waste-core 36c.” In some embodiments, nuclear-waste-core 36c or portions thereof may be located (e.g., placed) within a given waste-capsule 25. These steps 805 and 807 may be accomplished by robotic means (with or without shielding in some embodiments) with little or minimal radiation exposure problems to personnel. Steps 805 and 807 may avoid or mitigate potential problems of high cost, time, and human safety that occur if fuel rod assembly 36, which is relatively complex, were completely deconstructed into its constituent elements for pre-storage and disposal processing. FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, FIG. 6E, and FIG. 6F depict various aspects of various embodiments of the present invention. In FIG. 6A a location of carrier tube 34 (waste-capsule 25) in deep-geological-formation 38 may show use of centralizer 37b. In some embodiments, centralizer 37b may allow outer pipe 31 to “standoff” from initial lateral borehole 32 within deep-geological-formation 38. In some embodiments, use of centralizer 37b around an outside portion of outer pipe 31 may then provide a substantially annual void space between outer surfaces of outer pipe 31 and surfaces of initial lateral borehole 32; which may then be substantially filled with cement 30b. In some embodiments, cement 30b may be injected as slurry into this substantially annular void space. In some embodiments, initial lateral borehole 32 may be a portion of primary lateral wellbore 20, secondary lateral wellbore 20a, and/or vertical-wellbore 15. In some embodiments, initial lateral borehole 32 may be formed from drilling hardware of drilling-rig 10. In some embodiments, outer pipe 31 may be a structural member. In some embodiments, outer pipe 31 may have a pre-determined length and a predetermined diameter. In some embodiments, outer pipe 31 may be an elongate member; that may be substantially hollow. In some embodiments, outer pipe 31 may be a cylindrical member. In some embodiments, outer pipe 31 may be substantially rigid to semi-rigid. In some embodiments, outer pipe 31 may be substantially constructed from one or more of: a steel, steel like alloy, stainless steel, copper, aluminum, zircalloy, combinations thereof, and/or the like. In some embodiments, outer pipe 31 may be described as at least one layer of pipe. FIG. 6B may show nuclear waste core 36c or portions thereof housed within carrier tube 34. In some embodiments, within carrier tube 34 may be nuclear waste core 36c or portions thereof. In some embodiments, carrier tube 34 may comprise one or more supports 39. In some embodiments, a given support 39 may be a structural member. In some embodiments, use of one or more supports 39 within carrier tube 34 may aid in positioning and/or locating nuclear waste core 36c or portions thereof within carrier tube 34. In some embodiments, nuclear waste core 36c may be suspended internally (e.g., coaxially) within carrier tube 34 by supports 39. FIG. 6C may depict protective-medium 35 located substantially around nuclear waste core 36c or substantially around portions thereof. In some embodiments, carrier tube 34 may comprise one or more valves 42. In some embodiments, valve 42 may permit access into internal volumes of carrier tube 34. In some embodiments, valve 42 may permit protective-medium 35 to be injected (e.g., pumped) into internal void volumes of carrier tube 34; in which case valve 42 may be characterized as an injector valve or as an injector port. In some embodiments, valve 42 may be a relief valve or an overflow port and may permit excess protective-medium 35 to exit carrier tube 34. In some embodiments, protective-medium 35 may substantially occupy internal volumes of carrier tube 34 that would otherwise be void space. In some embodiments, protective-medium 35 may help to seal nuclear waste core 36c (e.g., SNF and/or HLW) within carrier tube 34. In some embodiments, protective-medium 35 may help to waterproof carrier tube 34. In some embodiments, due to densities of protective-medium 35, protective-medium 35 may help to absorb radioactive emissions of nuclear waste core 36c. In some embodiments, due to heat capacities of protective-medium 35, protective-medium 35 may help to absorb heat emissions from nuclear waste core 36c. In some embodiments, protective-medium 35 may be substantially constructed from one or more: hydrocarbons, petroleum derivatives, high temperature hydrocarbon derived products, tar, bitumen, heavy crude oil, bentonite clay suspensions, oils, slurries, combinations thereof, and/or the like. FIG. 6C may also depict transverse sectional-line 7-7. FIG. 7 may depict the transverse cross-sectional view derived from sectional-line 7-7 shown in FIG. 6C. FIG. 6D may show valve 42 located on a terminal end of carrier tube 34. In some embodiments, a given carrier tube 34 (or a given waste-capsule 25) may have two opposing terminal ends (see e.g., FIG. 3). In some embodiments, at each such opposing terminal end of a given carrier tube 34 (or a given waste-capsule 25) may be one or more valves 42. In some embodiments, a valve 42 at one such terminal end may be for injection; while a valve 42 disposed oppositely at the other terminal end may be for relief. While FIG. 6D may show one such terminal end, the other opposing terminal end may be substantially a mirror image of FIG. 6D. FIG. 6E may be longitudinal cross-sectional schematic view, similar to FIG. 6A. In some embodiments, for example, as shown in FIG. 6E, mechanical plugs 33a may be inserted into inner pipe 33 at each end of inner pipe 33 to hold a given inserted carrier tube 34 in place within inner pipe 33. In some embodiments, inner pipe 33 may be located within outer pipe 31. In some embodiments, inner pipe 33 and outer pipe 31 may be substantially coaxial with respect to each other. In some embodiments, inner pipe 33 and outer pipe 31 may be constructed from the same or similar types of materials. In some embodiments, inner pipe 33 may have a pre-determined length and a predetermined diameter. In some embodiments, inner pipe 33 may be a tube, tubular, and/or a casing. In some embodiments, inner pipe 33 may be a structural member. In some embodiments, inner pipe 33 may be an elongate member; that may be substantially hollow. In some embodiments, inner pipe 33 may be a cylindrical member. In some embodiments, inner pipe 33 may be substantially rigid to semi-rigid. In some embodiments, inner pipe 33 may be described as at least one layer of pipe. In some embodiments, the at least one layer of pipe may comprise outer pipe 31 and inner pipe 33. Continuing discussing FIG. 6E, in some embodiments, one or more non-waste-bearing-spacers 44 may be disposed between waste-capsules 25, within a given run of inner pipe 33 or within a given run of initial lateral borehole 32. In some embodiments, a given non-wastebearing-spacer 44 may comprise two opposing terminal ends. In some embodiments, a given non-waste-bearing-spacer 44 may be an elongate member. In some embodiments, a given nonwaste-bearing-spacer 44 may be a substantially cylindrical member. In some embodiments, a given non-waste-bearing-spacer 44 may be rigid to semi-rigid. In some embodiments, a given non-waste-bearing-spacer 44 may be a structural member. In some embodiments, a given nonwaste-bearing-spacer 44 may function as a heat sink. In some embodiments, a given non-wastebearing-spacer 44 may be substantially or partially constructed from one or metals, such as steel, aluminum, alloys thereof, and/or the like. In some embodiments, one or more non-waste-bearing-spacer 44 disposed between waste-capsules 25, along with these waste-capsules 25 may form a waste-string. In some embodiments, a given waste-capsule 25 may be attached to a given non-waste-bearing-spacer 44, e.g., at mating (or at abutting) respective terminal ends. In some embodiments, a nature of this attachment may be removable. In some embodiments, a given non-waste-bearing-spacer 44 may be attached to another given non-waste-bearing-spacer 44, e.g., at mating (or at abutting) respective terminal ends. In some embodiments, a nature of this attachment may be removable. Calculations of a heat load generated by degrading of radioactive waste in the waste-capsules 25 may be made to determine a quantity, length, and/or materials of non-waste-bearing-spacer 44 needed to keep this heat flux within predetermined limits. Such calculations may provide limits to quantity, length, and/or materials of installed non-waste-bearing-spacer(s) 44 in the waste-string that also may include at least one waste-capsule 25. FIG. 6F may depict pipe-coupling 40 which may be used to link to proximate inner pipes 33 to each other, in some embodiments. In some embodiments, pipe-coupling 40 may be a hollow cylindrical sleeve, with inner threading. In some embodiments, ends of inner pipes 33 may have outer threading, which may be complimentary with the inner threading of pipe-coupling 40. In some embodiments, pipe-coupling 40 may comprise a movable or articulable joint. In some embodiments, pipe-coupling 40 may be flexible. FIG. 7 may depict a transverse cross-sectional view through a section of initial lateral borehole 32; wherein this cross-section is made at sectional-line 7-7 shown in FIG. 6C. FIG. 7 may show innermost nuclear waste core 36c. In some embodiments, nuclear waste core 36c may be a fuel-rods-bundle 36a of still intact nuclear fuel rods (or portions thereof) disassembled from fuel rod assembly 36. In some embodiments, attached externally (or in physical contact with) to nuclear waste core 36c, at predetermined locations, may be supports 39. See also, FIG. 6A, FIG. 6B, FIG. 6C, and FIG. 6D. Continuing discussing FIG. 7, in some embodiments, implemented along rectilinear faces of nuclear waste core 36c at these predetermined locations may be supports 39, which may support nuclear waste core 36c inside carrier tube 34. In some embodiments, disposed around supports 39 and around nuclear waste core 36c and within carrier tube 34 may be void space; wherein this void space may be substantially occupied by protective-medium 35. In some embodiments, carrier tube 34 may be a first concentric layer radially outward from nuclear waste core 36c and which may completely surround nuclear waste core 36c, including surrounding nuclear waste core 36c at its terminal ends. In some embodiments, carrier tube 34 may be a structural member. In some embodiments, carrier tube 34 may be an elongate member. In some embodiments, carrier tube 34 may be a substantially cylindrical member. In some embodiments, carrier tube 34 may be a substantially rigid to substantially semi-rigid. In some embodiments, carrier tube 34 may house SNF and/or HLW, such as nuclear waste core 36c. In some embodiments, carrier tube 34 may be a substantially constructed from and/or have a layer substantially constructive from corrosive resistant materials; wherein such materials may be resistive to radiation and/or heat. In some embodiments, carrier tube 34 may be substantially constructed of a metal or a metallic alloy which may be characterized by both its strength and its corrosion resistance. In some embodiments, carrier tube 34 may be substantially constructed of one or more of: steel, stainless steel, aluminum, cooper, zircalloy, combinations thereof, and/or the like. In some embodiments, carrier tube 34 may be at least ½ (0.5) inch in wall thickness. In some embodiments, directly adjacent and juxtaposed externally to carrier tube 34 may be inner pipe 33. In some embodiments, inner pipe 33 may provide both external support and increased strength to carrier tube 34 which carries nuclear waste core 36c. In some embodiments, a wall thickness of inner pipe 33 may be at least ½ (0.5) inch. In some embodiments, inner pipe 33 may be substantially constructed of a steel, metal, and/or alloy, with yield strength in excess of 75,000 psi. In some embodiments, such a steel type may be at least N-80 grade and or P-110 grade or better. In some embodiments, use of inner pipe 33 may provide additional engineering barriers to protect SNF and/or HLW while buried according to one or more embodiments of the present invention. Continuing discussing FIG. 7, in some embodiments, disposed on an external surface of inner pipe 33 may be centralizers 37a. In some embodiments, such centralizers 37a may be spaced substantially orthogonally around external surfaces of inner pipe 33. In some embodiments, such centralizers 37a may keep inner pipe 33 at a “standoff” distance (predetermined distance) from outer pipe 31. In some embodiments, external and concentric to inner pipe 33 may outer pipe 31 of larger diameter than inner pipe 33. In some embodiments, use of centralizers 37a may form a substantially uniform annulus between outer pipe 31 and inner pipe 33. In some embodiments, this annulus (e.g., ring structure) may be substantially filled with cement 30a. In some embodiments, such positioned cement 30a may provide external support as well as an engineered barrier for the internal elements of waste-capsule 25 (i.e., of carrier tube 34). Continuing discussing FIG. 7, in some embodiments, disposed on an external surface of outer pipe 31 may be centralizers 37b. In some embodiments, such centralizers 37b may be spaced substantially orthogonally around external surfaces of outer pipe 31. In some embodiments, such centralizers 37b may keep outer pipe 31 at a “standoff” distance (predetermined distance) from initial lateral borehole 32. In some embodiments, use of centralizers 37b may form another substantially uniform annulus between initial lateral borehole 32 and outer pipe 31. In some embodiments, this annulus may be substantially filled with cement 30b. In some embodiments, such positioned cement 30b may provide external support as well as an engineered barrier for the internal elements of waste-capsule 25 (i.e., of carrier tube 34). FIG. 8 may depict a flowchart. FIG. 8 may depict various steps of method 800. In some embodiments, method 800 may be a method for handling nuclear waste. In some embodiments, method 800 may be a method for processing fuel rod assemblies 36 into nuclear waste cores 36c, for subsequent subterranean storage in deep-geological-formations 38, according to one or more embodiments of the present invention. In some embodiments, method 800 may be a method for subterranean storage of nuclear waste in deep-geological-formations 38. In some embodiments, method 800 may comprise one or more of: status 801, step 803, step 805, step, 807, step 809, step 811, step 813, step 815, step 817, step 819, step 821, step 823, step 825, step 827, step 829, step 831, step 833, and/or step 825. In some embodiments, status 801; and/or steps 803 through step 819 may occur away from subterranean storage location site; i.e., away from below where deep-geological-formation 38 may be located. In some embodiments steps 821 through step 835 may occur at or below the subterranean storage location site. Continuing discussing FIG. 8, in some embodiments, status 801 may be a status of when fuel rod assemblies 36 may be stored at the surface, such as in storage pools. For example, nuclear waste from the nuclear power plants 10a may be stored at status 801 for long term cooling for periods of several years, such as, between four and 30 years, or for up to 30 years or more in other embodiments. Such surface storage may be initially done in cooling pools; sometimes then later in casks or other massive protected containers on or near the surface. In some embodiments, step 803 may be step of receiving fuel rod assemblies 36 from that surface storage (e.g., from cooling pools or casks). That is, in some embodiments, the receiving step 803 may be a harvesting step, as in a step of harvesting fuel rod assemblies 36 from the surface storage. In some embodiments, step 803 may transition in step 805. Continuing discussing FIG. 8, in some embodiments, step 805 may be a step of disassembling fuel rod assemblies 36 into resulting sub-assemblies, for example, of nuclear waste cores 36c. In FIG. 8, “NWC” may stand for one or more nuclear waste cores 36c. In some embodiments, step 807 may be a step of disassembling fuel rod assemblies 36 into resulting nuclear waste cores 36c by using dividing-planes 36b. That is, step 807 may be a sub-step of step 805. As noted earlier, steps 805 and/or step 807, may be automated and performed by robotics, to increase safety to personnel. Such automation may be shielded (radiation shielding) in some embodiments. Such disassembly may be mechanical disassembly and separation. Resulting nuclear waste cores 36c from steps 805 and step 807 may be in rectangular prism form (i.e., in square matrix form). See also FIG. 4 and FIG. 5 and their corresponding discussion above. Continuing discussing FIG. 8, in some embodiments, step 805 may transition into step 809. In some embodiments, step 809 may be a step of inserting nuclear waste cores 36c into carrier tube(s) 34. In some embodiments, step 809 may include sub-step 811. In some embodiments, sub-step 811 may be optional. In some embodiments, sub-step 811 may be a step of supporting nuclear waste cores 36c within carrier tube(s) 34 with support(s) 39. In some embodiments, use of support(s) 39, may facilitate use of protective-medium 35 as noted above. See also, FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, and FIG. 7; as well as their corresponding discussions above. Continuing discussing FIG. 8, in some embodiments, step 813 may be a step of injecting protective-medium 35 into carrier tube(s) 34, e.g., via use of valve 42, as noted above. In some embodiments, carrier tube(s) 34 may be pre-loaded with protective-medium 35, prior to insertion of nuclear waste cores 36c into the given carrier tube 34 via step 809. That is in some embodiments, step 813 may precede step 809. In such embodiments, insertion of nuclear waste cores 36c into carrier tube 34, may then force excess protective-medium out of that given carrier tube 34, e.g., via valve 42 (e.g., as a relief valve). And then step 809 may progress into step 815. That is, in such embodiments, step 813 may progress into step 809, which may then progress to step 815. Step 809 may still also follow step 805. Whereas, in other embodiments, step 805 may progress to step 809, which may progress to step 813, which may progress to step 815. See FIG. 8. Continuing discussing FIG. 8, in some embodiments, step 815 may be a step of sealing a given carrier tube 34 that may comprise nuclear waste cores 36c. In some embodiments, step 815 may involve sealing terminal ends of the given carrier tube 34 via welding. In some embodiments, step 815 may involve sealing terminal ends of the given carrier tube 34 with mechanical plug(s) 33a. See e.g., FIG. 6E and its discussion above. Continuing discussing FIG. 8, in some embodiments, step 815 may progress into step 817. In some embodiments, step 817 may be a step of installing spacers 44, as needed for heat management, between the now sealed carrier tube(s) 34 (with nuclear waste cores 36c). See e.g., FIG. 6E and its above discussion. In such a manner a given waste-string may be formed. In some embodiments, a waste-string may comprise at least two carrier tubes 34 separated and attached to a common spacer 44. In some embodiments, step 817 may be optional. In some embodiments, where step 817 may be omitted, then step 815 may progress to step 819 or to step 821. Continuing discussing FIG. 8, in some embodiments, step 817 may then progress into step 819. In some embodiments, step 819 may be optional or used as desired or used as necessary. In some embodiments, step 819 may be a step of joining carrier tubes 34 together via use of pipe-coupling(s) 40. In some embodiments, such carrier tubes 34 may already be linked (e.g., attached to each other) via spacers 44, per step 817 as noted above. In some embodiments, step 819 may then progress into step 821. Continuing discussing FIG. 8, in some embodiments, step 821 may be a step of inserting the sealed carrier tubes 34 into inner pipes 33; and subsequently placing such inner pipes 33 into drilled boreholes. In some embodiments, step 815 may progress directly to step 821 (e.g., when spacers 44 and pipe-couplings 40 may not be used). In some embodiments, step 817 may progress directly to step 821 (e.g., when pipe-couplings 40 may not be used). In some embodiments, when step 819 progresses into step 821, then the sealed carrier tubes 34 that may be inserted into inner pipe(s) 33 may include use of spacers 44 and/or use of pipe-couplings 40. In some embodiments, step 821 may include use of mechanical plugs 33a in inner pipes 33 at terminal ends of carrier tube(s) 34 also within that given inner pipe 33. Use of such mechanical plugs 33a may minimize unintended shifting of the inserted carrier tube(s) 34 within inner pipe(s) 33; e.g., during transportation of such loaded inner tube(s) 33 or during loading of the loaded inner pipe(s) 33. In some embodiments, as shown in FIG. 8, step 821 may also loop back onto step 819; e.g., when inner pipes 33 may need to be joined via pipe-couplings 40. Continuing discussing FIG. 8, in some embodiments, one or more of step 825, step 827, step 829, step 831, and/or step 833 may progress and lead to step 821. In some embodiments, step 825 may be a step of drilling the given borehole(s) by use of drilling-rig 10. In some embodiments, step 825 may yield one or more of: vertical-wellbore 15, primary lateral wellbore 20, secondary lateral wellbore 20a, and/or initial lateral borehole 32. In some embodiments, step 825 may result in one or more wellbores being drilled into deep-geological-formation 38. Continuing discussing FIG. 8, in some embodiments, step 825 may progress into step 827. In some embodiments, step 827 may be a step of loading outer pipes 31 into the resulting boreholes from step 825. In some embodiments, loading of these outer pipes 31 into the resulting boreholes may also entail fitting such outer pipes 31 with centralizers 37b. Continuing discussing FIG. 8, in some embodiments, step 827 may progress into step 829. In some embodiments, step 829 may be an injecting cement step; such a cement casing (see e.g., cement 30b in FIG. 6A) may be substantially formed in an annulus around outer pipes 31 and within boreholes (e.g., one or more of vertical-wellbore 15, primary lateral wellbore 20, secondary lateral wellbore 20a, and/or initial lateral borehole 32) that may house such outer pipes 31. In some embodiments, during step 829, cement (while in un-cured slurry form) may be pumped into and within the outer pipes 31, and subsequently forced out of an open bottom end of outer pipes 31, wherein such pressure may then force this cement slurry into the noted annular space. In some embodiments, step 829 may be a step of circulation of cement. In some embodiments, after such injected (e.g., pumped) cement per step 829 has sufficiently cured, interior portions of outer pipes 31 may be cleaned of undesirable residual cement; e.g., via use of wiper plugs. Continuing discussing FIG. 8, in some embodiments, step 829 may progress into step 831. In some embodiments, step 831 may be a step of loading inner pipes 33 into outer pipes 31. In some embodiments, loading of these inner pipes 33 into outer pipes 31 may also entail fitting such inner pipes 33 with centralizers 37a; such axis of inner pipes 33 may be substantially concentric (coaxial) with respect to axis of outer pipes 31. Continuing discussing FIG. 8, in some embodiments, step 831 may progress into step 833. In some embodiments, step 833 may be an injecting cement step; such that a cement layer (see e.g., cement 30a in FIG. 6A) may be substantially formed in an annulus around inner pipes 33 and within outer pipes 31 that may house such inner pipes 33. In some embodiments, during step 833, cement (while in un-cured slurry form) may be pumped into and within the inner pipes 33, and subsequently forced out of an open bottom end of inner pipes 33, wherein such pressure may then force this cement slurry into the noted annular space between the exterior of inner pipes 33 and the interior of outer pipes 31. In some embodiments, step 833 may be a step of circulation of cement. In some embodiments, after such injected (e.g., pumped) cement per step 833, interior portions of inner pipes 33 may be cleaned of undesirable residual cement; e.g., via use of wiper plugs. In some embodiments, step 833 may then progress into step 821; wherein waste-strings may be installed (inserted) to the inner pipes 33. Continuing discussing FIG. 8, in some embodiments, step 821 may progress into step 823. In some embodiments, step 823 may be a step of finishing inserting the sealed carrier tubes 34 into the inner pipes 33; wherein these inner pipes 33 may already be installed into the outer pipes 31. In some embodiments, step 823 may be a step of completing sequential insertion of all carrier tubes 34 into inner pipes 33. In some embodiments, such carrier tubes may be with spacers 44 per step 817. In some embodiments, step 823 may loop back onto step 821 depending on the total number of carrier tubes to be inserted. Continuing discussing FIG. 8, in some embodiments, step 823 may progress into step 835. In some embodiments, step 835 may be a step of sealing the various boreholes. Various backfills, including, but not limited to cement pours, may be used for this purpose. In some embodiments, retrieval of subterranean stored waste-capsule(s) 25 (and/or carrier tube(s) 34) stored according to method 800 may be straightforward. In some embodiments, such subterranean stored waste-capsule(s) 25 (and/or carrier tube(s) 34) may be retrieved using an “overshot” fishing tool (e.g., as used in oilfield operations) and returned sequentially to the surface in a routine operation. Then once on the surface, protective-medium 35 inside a given carrier tube 34 and surrounding the nuclear waste core 36c may be removed by an efficient dissolution process with the appropriate solvents; and thus making nuclear waste core 36c fully accessible, for various purposes, including research, investigation, observation, and/or available for re-processing, or relocation. Systems and methods for deep geological storage of nuclear waste have been described. The foregoing description of the various embodiments of the invention has been presented for the purposes of illustration and disclosure. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit of the invention. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. |
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046845038 | abstract | A reconstitutable fuel assembly includes an improved attaching structure which has a plurality of coupling sleeves interfitting the upper hold-down plate, lower adapter plate and a plurality of hold-down springs of the top nozzle of the assembly. The coupling sleeves insert over a plurality of extensions extending upwardly from the main bodies of the guide thimbles. The sleeves rest on annular ledges formed on the bottom portions of the respective extensions. A removable cap is attached to the top portion of each of the thimbles extensions and applied to the upper portion of each of the coupling sleeves to releasably lock the coupling sleeves on the guide thimble extensions. In view that the coupling sleeves are fixed to the adapter plate at their lower portions, the sleeves and hold-down plate, adapter plate and hold-down springs disposed between the plates and encircling individual sleeves can be removed together from the fuel assembly as a unitary subassembly upon removal of the removable caps. |
description | The field of the present invention relates to apparel worn by a person in or on a body of water. In particular, methods and apparel are disclosed for attenuating electromagnetic fields emanating from a person in or on a body of water. The subject matter disclosed or claimed herein may be related to subject matter disclosed or claimed in: (i) U.S. non-provisional application Ser. No. 12/347,967 filed Dec. 31, 2008 in the names of Michael D. Slinkard and John M. Maupin and entitled “Methods and apparel for attenuating electromagnetic fields emanating from a hunter,” (ii) U.S. non-provisional application Ser. No. 12/347,971 filed Dec. 3, 2008 in the names of Michael D. Slinkard and John M. Maupin and entitled “Methods and hunting blind for attenuating electromagnetic fields emanating from a hunter,” and (iii) U.S. non-provisional application Ser. No. 12/428,763 filed Apr. 23, 2009 in the names of Michael D. Slinkard and John M. Maupin and entitled “Methods and apparel for attenuating electromagnetic fields emanating from an animal handler.” Each of said applications is incorporated by reference as if fully set forth herein. It is known that the human body generates electromagnetic fields during normal body functions, and that those fields can increase in strength with increased activity, excitement, emotion, or attention. For example, brain activity, nerve activity, and muscle activity all result in electric fields that emanate from the body. Detection and characterization of such fields is the basis for the conventional clinical techniques of electrocardiography (i.e., ECG or EKG), electroencephalography (i.e., EEG), and electromyelography (i.e., EMG). For the purposes of the present disclosure or claims, “electromagnetic” is intended to denote those fields that have temporal variations well below so-called optical frequencies (i.e., having frequency components no greater than about 1 gigahertz (GHz), typically no greater than about 1 megahertz (MHz), and often no greater than about 1 kilohertz (kHz). It is also known that at least some animals can detect or respond to electromagnetic fields. For example, sharks detect electric fields emanating from prey by means of special sensing organs called the ampullae of Lorenzini (http://en.wikipedia.org/wiki/Ampullae_of_Lorenzini). A shark-repelling system is disclosed in U.S. Pat. No. 4,211,980 that generates an electric field to drive away the sharks. Other animals are believed to navigate their natural migratory routes using the earth's magnetic field (http://www.pbs.org/wgbh/nova/magnetic/animals.html). Fabrics exist that are adapted to attenuate or block electromagnetic fields. They typically include electrically conductive fibers (metal, carbon nanotubes, or other conductive fibers) incorporated into the fabric along with more typical textile fibers. Garments constructed from such fabrics are conventionally used to shield a human wearer from surrounding electromagnetic fields. Such shielding can be usefully employed into safety equipment or apparel, can be worn by or applied to a patient to provide various health or therapeutic benefits, or for other purposes. Examples of such fabrics and their uses can be found in the following references, each of which is incorporated by reference as if fully set forth herein: U.S. Pat. No. 7,354,877 entitled “Carbon nanotube fabrics” issued Apr. 8, 2008 to Rosenberger et al; U.S. Pat. No. 6,868,854 entitled “Method and article for treatment of fibromyalgia” issued Mar. 22, 2005 to Kempe; Pat. Pub. No. 2004/0053780 entitled “Method for fabricating nanotube yarn” published Mar. 18, 2004 in the names of Jiang et al; U.S. Pat. No. 6,265,466 entitled “Electromagnetic shielding composite comprising nanotubes” issued Jul. 24, 2001 to Glatkowski et al; U.S. Pat. No. 6,146,351 entitled “Method of reducing delayed onset muscle soreness” issued Nov. 14, 2000 to Kempe; U.S. Pat. No. 5,621,188 entitled “Air permeable electromagnetic shielding medium” issued Apr. 15, 1997 to Lee et al; U.S. Pat. No. 4,825,877 entitled “Method of pain reduction using radiation-shielding textiles” issued May 2, 1989 to Kempe; and U.S. Pat. No. 4,653,473 entitled “Method and article for pain reduction using radiation-shielding textile” issued Mar. 31, 1987 to Kempe. There is no teaching or suggestion in the prior art to attenuate or block electromagnetic fields emanating from a human body, or that such attenuation or blocking would be desirable. A method comprises attenuating, while in or on a body of water, one's own emanated electromagnetic field by wearing at least one article of apparel that includes an electromagnetically shielding fabric. The shielding fabric comprises a substantially continuous system of conductive fibers combined with a non-conductive fabric. The attenuation of one's own emanated electromagnetic field decreases the likelihood of being located in the body of water by a predator detecting the emanated electromagnetic field. Another method comprises attenuating the electromagnetic field emanated by a person in or on a body of water. The attenuation is accomplished by (i) providing to the person at least one article of apparel that includes the electromagnetically shielding fabric, and (ii) instructing the person to wear, while in or on a body of water, at least one said article of apparel. The attenuation of the electromagnetic field emanated by the person decreases the likelihood of a predator in the body of water locating the person by detecting the emanated electromagnetic field. Objects and advantages pertaining to apparel incorporating electromagnetic shielding fabric may become apparent upon referring to the exemplary embodiments illustrated in the drawings and disclosed in the following written description or appended claims. The embodiments shown in the Figures are exemplary, and should not be construed as limiting the scope of the present disclosure or appended claims. Electromagnetically shielding apparel can be advantageously employed during a variety of activities or in a variety of situations. In one example, such electromagnetic shielding can be incorporated into any suitable apparel worn while the wearer 50 is in or on a body of water 500 (e.g., river, lake, sea, ocean), as in FIGS. 5A-5B. Blocking or attenuating the electromagnetic field 52 emanated by the person 50 can reduce the likelihood of detection of the wearer 50 by an aquatic or marine water-borne predator 55, e.g., a shark. Without electromagnetically shielding apparel (as in FIG. 5B), the predator 55 might detect the person in the water from a larger distance D2. With electromagnetically shielding apparel (as in FIG. 5A), the predator 55 might only detect the person 50 in the water after approaching more closely (distance D1 that is smaller than distance D2). Shielding of a person's emanated electromagnetic field while in a body of water can be particularly advantageous under conditions of poor underwater visibility, wherein a water-borne predator might rely more heavily on electromagnetic prey detection, and wherein a person would have more difficulty seeing and avoiding a water-borne predator. Electromagnetically shielding apparel can be provided to or worn by, e.g., bathers, waders, swimmers, surfers, boaters, sailors, personal water craft users, wind surfers, para-sailors, para-surfers, snorkelers, or divers (free, scuba, or other) in a river, lake, sea, ocean, or other body of water. Examples of suitable articles of apparel can include, but are not limited to, trunks, shirts, bathing suits, wet suits, dry suits, deck apparel, and so on. Some examples are shown in FIG. 2. Electromagnetically shielding apparel can be included with other water survival gear on a vessel or aircraft, or electromagnetically shielding fabric can be incorporated into conventional survival gear, e.g., a life vest, life raft, or exposure suit. There is no teaching or suggestion in the prior art to attenuate or block electromagnetic fields emanating from a person in or on a body of water, or that such attenuation or blocking would be desirable. Another exemplary method comprises attenuating, while hunting, the electromagnetic field emanated by a hunter. The electromagnetic field is attenuated by at least one article of apparel worn by the hunter while hunting. The article comprises an electromagnetically shielding fabric, which fabric comprises a substantially continuous system of conductive fibers combined with a non-conductive fabric. Another method can include providing at least one such article of electromagnetically shielding apparel to a hunter and instructing that hunter to wear the article while hunting. That method can also include constructing at least one said article of apparel prior to providing it to the hunter. There is no teaching or suggestion in the prior art to attenuate or block electromagnetic fields emanating from a hunter while hunting (or an observer while observing wildlife), or that such attenuation or blocking would be desirable. By attenuating or blocking electromagnetic fields emanating from a hunter or observer, that hunter or observer can more closely approach an animal without detection, or detection of that hunter or observer by the animal can be made less likely. It is therefore desirable to provide hunting apparel (including, e.g., clothing, eyewear, headwear) or a hunting blind that attenuates or blocks electromagnetic fields emanating from the hunter or observer, thereby decreasing the likelihood of detection of the hunter or observer by an animal that is sensitive to electromagnetic fields, and increasing the likelihood that the hunter will be successful in taking the animal, or that the observer will be successful in making the desired observation of the animal. The hunter wears the article of apparel while hunting. The electromagnetically shielding fabric blocks or attenuates an electromagnetic field emanating from the hunter's body, thereby decreasing the likelihood that he or she will be detected by a prey animal sensitive to such electromagnetic fields. An electromagnetic field 12 emanated by a hunter 10 and thus attenuated can be detected by an animal 14 at a maximum distance D1 (FIG. 1A) that is smaller than the maximum detection distance D2 at which an unattenuated field 12 (FIG. 1B) can be detected by that same animal 14. The hunter 10 can therefore approach the animal 14 more closely without detection, facilitating the kill. In measurements of electromagnetic fields emanating from a human body, reductions of field strength ranging from about 38% to about 65% have been observed, as shown illustrated in the experimental results disclosed in an Appendix attached to application Ser. Nos. 12/347,967, 12/347,971, and 12/428,763 (already incorporated by reference). Any suitable, desirable, or practicable reduction of emanated electromagnetic field strength shall fall within the scope of the present disclosure or appended claims. It is possible in some instances of hunting that a human hunter might become the prey of a predatory animal, either the animal he is hunting or another animal in the same habitat. In those circumstances, the electromagnetically shielding apparel can reduce the likelihood that the predatory animal will locate the human hunter by detecting the electromagnetic field emanated by the hunter. As illustrated by the examples of FIG. 2, an article of hunting apparel incorporating electromagnetically shielding fabric can comprise an article of clothing (e.g., pants 18, shorts, shirt 16, undergarments, leggings, sleeves, gloves 20, mittens, jacket, coat, vest, overalls, waders, or snowsuit), footwear (e.g., shoes, boots 24, socks 22, or boot liners), headwear (e.g., hood 12, facemask 14, or hat), or eyewear (e.g., glasses or goggles 26). Another exemplary method comprises attenuating, while handling an animal, the electromagnetic field emanated by a handler of the animal. The electromagnetic field is attenuated by at least one article of apparel worn by the handler while handling the animal. The article of apparel comprises an electromagnetically shielding fabric, which fabric comprises a substantially continuous system of conductive fibers combined with a non-conductive fabric. Another method can include providing at least one such article of electromagnetically shielding apparel to a handler and instructing that handler to wear the article while handling the animal. That method can also include constructing at least one said article of apparel prior to providing it to the handler. There is no teaching or suggestion in the prior art to attenuate or block electromagnetic fields emanating from an animal handler while handling an animal, or that such attenuation or blocking would be desirable. Attenuating or blocking electromagnetic fields emanating from a person can be advantageous while handling an animal. It has been observed frequently that animals can be affected by emotional responses or the emotional state of a person nearby, e.g., a person's anxiety can cause nervous or uneasy behavior of the animal, or a person's fear can trigger an aggressive response from the animal. Sensing by an animal of a person's emotional state or response might occur in a variety of ways, e.g., by detecting by smell pheromones released as a result of the person's emotional state or response, or by sensing emotion-related electromagnetic fields resulting from the person's emotional state or responses. Attenuating or blocking fields emanating from the person can advantageously reduce the effect on the animal of the emotional state or an emotional response of the person. “Handling” an animal shall encompass, inter alia: (i) literal handling of the animal by holding or touching the animal; (ii) handling the animal using a rope, chain, leash, muzzle, harness, saddle, reins, yoke, prod, whip, or other equipment; (iii) feeding the animal; (iv) guiding, directing, herding, capturing, or restraining the animal; (v) riding the animal; (vi) using the animal to pull or push a vehicle, object, or equipment of any sort; (vii) using the animal in a performance, display, or demonstration; (viii) training the animal for any purpose, including but not limited to those listed here; (ix) conducting veterinary examination or treatment of the animal; (x) using an animal to train another handler to perform any animal-handling task, including but not limited to those listed here; (xi) using an animal to learn from another handler to perform any animal-handling task, including but not limited to those listed here; and (xii) other activities that involve interaction between a person and an animal. An animal handler wears the article of electromagnetically shielding apparel while handling the animal. Instead or in addition, other people likely to be near the animal (i.e., bystanders) can wear articles of electromagnetically shielding apparel; for purposes of the present disclosure or appended claims, the terms “handler” and “handling” shall be construed as including both those persons interacting directly with the animal as well as bystanders that might interact with the animal indirectly (e.g., by being near enough to affect the animal via pheromones or emanated electromagnetic fields). By blocking or attenuating electromagnetic fields emanating from a person near the animal, the animal is less likely to sense such fields that arise from an emotional response or state of the person, and is therefore also less likely to react to that emotional state or reaction. In particular, emotional responses or states that might cause undesirable behavior of the animal (e.g., flight or aggression) are less likely to be sensed by the animal. Such emotional states or responses can arise for a variety of reasons, e.g., a handler's or bystander's fear of the animal, a handler's frustration with the animal's behavior or response (or lack thereof) to its training, a handler's frustration or discomfort while being taught how to handle an animal, or an instructor's frustration at a handler trainee's response (or lack thereof) to his/her instruction. Any other use of electromagnetically shielding clothing, in a situation wherein blocking or attenuation of the wearer's emanated electromagnetic field may be advantageous, shall fall within the scope of the present disclosure, whether that situation involves an animal or not. The electromagnetically shielding fabric may block or attenuate electric fields, magnetic fields, or both, and any of those alternative shall fall within the scope of the present disclosure or appended claims. It may be preferable under particular circumstances to preferentially block either electric fields or magnetic fields, and such uses are encompassed by the present disclosure or appended claims. In addition to providing electromagnetic shielding, the article of apparel can also be adapted or arranged to decrease visual or olfactory perception of the hunter by a prey animal or predatory animal, or of a person in a body of water by a water-borne predator. For example, articles of apparel 30 can include a visual camouflage pattern on at least a portion of its outer surface (as in FIGS. 3A and 3B). Many examples of such visual camouflage are known, and some examples are disclosed in various of the incorporated references. Any suitable visual camouflage pattern, including both two- and three-dimensional patterns, shall fall within the scope of the present disclosure or claims. In another example, the article of apparel can include an odor absorber, suppressant, attenuator, or blocker. Some examples of these are disclosed in various of the incorporated references. Any suitable odor absorber, suppressant, attenuator, or blocker shall fall within the scope of the present disclosure or claims. By combining electromagnetic shielding with visual camouflage or odor control, the overall likelihood that the hunter will be detected by a prey animal can be decreased, and the probability of a successful kill can be increased. Use of odor control can also reduce the likelihood that an animal will sense (via pheromones) and react to an emotional response or the emotional state of a handler. Any suitable fabric can be employed that incorporates conductive fibers of any suitable type to form a substantially continuous electrical conduction network in the fabric. The conduction network 42 can be arranged irregularly (as in the example of FIG. 4A), in a grid-like pattern (as in the example of FIG. 4B), or in any other suitable, desirable, or practicable arrangement. The conductive fibers can be intermingled with non-conductive fibers 44 to form the shielding fabric 40 (in a regular, interwoven arrangement or in an irregular arrangement). Examples of suitable fibers include typical textile fibers, e.g., wool, silk, or other natural polyamide fibers; cotton, rayon, or other cellulosic fibers; or nylon, polyester, Kevlar, or other synthetic fibers. Alternatively, the conductive fibers 42 (regularly or irregularly arranged) can be applied to a surface of a non-conducting fabric 46 to form the shielding fabric 40. In that latter case, the non-conducting fabric can comprise a woven, textile fabric, or can comprise a substantially continuous sheet fabric such as a plastic sheet or polymer film. The conductive fibers can be combined with the non-conducting fabric in any suitable, desirable, or practicable way, including those described above or others not explicitly disclosed herein, and all such combinations shall fall within the scope of the present disclosure or appended claims. Any suitable conductive fibers can be employed that provide sufficient conductivity for providing electromagnetic shielding and that can form fibers suitable for incorporation into a fabric. In various examples disclosed in the incorporated references, the conductive fibers comprise stainless steel, copper, silver, carbon (e.g., fibers, graphite, or nanotubes), conductive ceramic, conductive polymer, or conductive nanotubes. Any suitable composition of the electromagnetic shielding fabric can be employed. One suitable example is Farabloc® fabric described in incorporated U.S. Pat. Nos. 4,653,473, 4,825,877, 6,146,351, and 6,868,854. In various examples of such fabrics disclosed in the incorporated references, the fabric includes between about 2% and about 35% by weight of the conductive fibers. Other exemplary fabrics can include greater than about 5%, greater than about 10%, greater than about 15%, greater than about 20%, greater than about 25%, or greater than about 30% by weight of the conductive fibers, while still other exemplary fabrics can include less than about 30%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, or less than about 5% by weight of the conductive fibers. Fabrics having greater than 35% by weight of conductive fibers can be employed if suitable, desirable, or practicable. Higher compositions of conductive fiber typically can provide greater electromagnetic shielding, but might also come at a higher cost or weight, or might yield a fabric with other undesirable properties. Any suitably optimized composition can be used in a given situation. A number of case studies are presented in application Ser. Nos. 12/347,967, 12/347,971, and 12/428,763 (already incorporated by reference). Those case studies demonstrate the effectiveness of garments incorporating electromagnetically shielding fabric for decreasing the likelihood of detection by prey animals while hunting. In addition to the case studies, a more controlled, systematic test of the effect of electromagnetically shielding fabric on animals' perception of the electromagnetic field emanating from a human body is disclosed in a manuscript reproduced in an Appendix attached to those incorporated applications. Another exemplary method comprises attenuating, while hunting, the electromagnetic field emanated by a hunter within a hunting blind. The hunting blind includes an electromagnetically shielding fabric of any suitable type described herein. Another method can include providing an electromagnetically shielding hunting blind to a hunter and instructing that hunter to remain within the hunting blind while hunting. That method can also include constructing the hunting blind prior to providing it to the hunter. There is no teaching or suggestion in the prior art to incorporate electromagnetically shielding fabric into hunting apparel or a hunting blind, or that the incorporation of such fabrics would be desirable. A several examples of a hunting blind are shown in application Ser. Nos. 12/347,967, 12/347,971, and 12/428,763 (already incorporated by reference). A hunting blind can include electromagnetically shielding fabric arranged to attenuate the electromagnetic field emanating from a hunter within the hunting blind. The attenuation of the hunter's electromagnetic field enables prey animals to approach the blind more closely before perceiving the hunter's presence within the blind. The hunting blind can be arranged in any suitable configuration while remaining within the scope of the present disclosure or appended claims. Many examples of hunting blinds can be found in the prior art (some of which are cited above), and any of them can incorporate electromagnetically shielding fabric to attenuate the electromagnetic field emanating from a hunter within the hunting blind. The electromagnetically shielding fabric can be integrated into the structure of the hunting blind, or can be provided as a add-on covering or lining for an existing hunting blind. It may be desirable in many circumstances to arrange the shielding fabric of the hunting blind to substantially completely enclose the hunter in all directions (except for openings provided for viewing the prey and for shooting through), although such complete enclosure may not always be necessary. If the hunting blind is elevated and if such complete enclosure is desired, the shielding fabric can be incorporated into the bottom surface of the blind (below the hunter) as well as into the blind's other surfaces. If the hunting blind rests on the ground, the shielding fabric can be incorporated into the bottom surface of the blind, the shielding fabric can be omitted from the bottom surface, or the blind may not even have a bottom surface; the ground can provide electromagnetic shielding in a downward direction if no shielding fabric is present below the hunter. Blinds that do not substantially enclose the hunter shall also fall within the scope of the present disclosure or appended claims. As with the articles of hunting apparel disclosed above, a hunting blind that incorporates electromagnetically shielding fabric can also include a visual camouflage pattern on at least a portion of its outer surface, or can also include an odor absorber, suppressant, attenuator, or blocker. Any suitable fabric composition (e.g., Farabloc®) can be incorporated into a hunting blind. It is intended that equivalents of the disclosed exemplary embodiments and methods shall fall within the scope of the present disclosure or appended claims. It is intended that the disclosed exemplary embodiments and methods, and equivalents thereof, may be modified while remaining within the scope of the present disclosure or appended claims. For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “a dog or a cat” would be interpreted as “a dog, or a cat, or both”; e.g., “a dog, a cat, or a mouse” would be interpreted as “a dog, or a cat, or a mouse, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either . . . or”, “only one of . . .”, or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure or appended claims, all instances of the words “comprising,” “including,” “having,” and variants thereof shall be construed as open ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof. |
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description | This application is a continuation-in-part of U.S. patent application Ser. No. 15/167,617 filed May 27, 2016, which is: a continuation-in-part of U.S. patent application Ser. No. 15/152,479 filed May 11, 2016, which: is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/087,096 filed Apr. 14, 2011, which claims benefit of U.S. provisional patent application No. 61/324,776 filed Apr. 16, 2010; and is a continuation-in-part of U.S. patent application Ser. No. 13/788,890 filed Mar. 7, 2013; is a continuation-in-part of U.S. patent application Ser. No. 14/952,817 filed Nov. 25, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 14/293,861 filed Jun. 2, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 12/985,039 filed Jan. 5, 2011, which claims the benefit of U.S. provisional patent application No. 61/324,776, filed Apr. 16, 2010; is a continuation-in-part of U.S. patent application Ser. No. 14/860,577 filed Sep. 21, 2015, which is a continuation of U.S. patent application Ser. No. 14/223,289 filed Mar. 24, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 12/985,039 filed Jan. 5, 2011, which claims the benefit of U.S. provisional patent application No. 61/324,776, filed Apr. 16, 2010; and is a continuation-in-part U.S. patent application Ser. No. 15/073,471 filed Mar. 17, 2016, which claims benefit of U.S. provisional patent application No. 62/304,839 filed Mar. 7, 2016, is a continuation-in-part of U.S. patent application Ser. No. 14/860,577 filed Sep. 21, 2015, which is a continuation of U.S. patent application Ser. No. 14/223,289 filed Mar. 24, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/572,542 filed Aug. 10, 2012, which is a continuation-in-part of U.S. patent application Ser. No. 12/425,683 filed Apr. 17, 2009, which claims the benefit of U.S. provisional patent application No. 61/055,395 filed May 22, 2008, now U.S. Pat. No. 7,939,809 B2; all of which are incorporated herein in their entirety by this reference thereto. Field of the Invention This invention relates generally to imaging and/or treatment of solid cancers. More particularly, the invention relates to control of a charged particle beam state using imaging in the cancer treatment room with the patient at least partially positioned for charged particle therapy. Discussion of the Prior Art Cancer Treatment Proton therapy works by aiming energetic ionizing particles, such as protons accelerated with a particle accelerator, onto a target tumor. These particles damage the DNA of cells, ultimately causing their death. Cancerous cells, because of their high rate of division and their reduced ability to repair damaged DNA, are particularly vulnerable to attack on their DNA. Patents related to the current invention are summarized here. Proton Beam Therapy System F. Cole, et. al. of Loma Linda University Medical Center “Multi-Station Proton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describe a proton beam therapy system for selectively generating and transporting proton beams from a single proton source and accelerator to a selected treatment room of a plurality of patient treatment rooms. Imaging P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,274,018 (Sep. 25, 2007) and P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,045,781 (May 16, 2006) describe a charged particle beam apparatus configured for serial and/or parallel imaging of an object. K. Hiramoto, et. al. “Ion Beam Therapy System and its Couch Positioning System”, U.S. Pat. No. 7,193,227 (Mar. 20, 2007) describe an ion beam therapy system having an X-ray imaging system moving in conjunction with a rotating gantry. C. Maurer, et. al. “Apparatus and Method for Registration of Images to Physical Space Using a Weighted Combination of Points and Surfaces”, U.S. Pat. No. 6,560,354 (May 6, 2003) described a process of X-ray computed tomography registered to physical measurements taken on the patient's body, where different body parts are given different weights. Weights are used in an iterative registration process to determine a rigid body transformation process, where the transformation function is used to assist surgical or stereotactic procedures. M. Blair, et. al. “Proton Beam Digital Imaging System”, U.S. Pat. No. 5,825,845 (Oct. 20, 1998) describe a proton beam digital imaging system having an X-ray source that is movable into a treatment beam line that can produce an X-ray beam through a region of the body. By comparison of the relative positions of the center of the beam in the patient orientation image and the isocentre in the master prescription image with respect to selected monuments, the amount and direction of movement of the patient to make the best beam center correspond to the target isocentre is determined. S. Nishihara, et. al. “Therapeutic Apparatus”, U.S. Pat. No. 5,039,867 (Aug. 13, 1991) describe a method and apparatus for positioning a therapeutic beam in which a first distance is determined on the basis of a first image, a second distance is determined on the basis of a second image, and the patient is moved to a therapy beam irradiation position on the basis of the first and second distances. Problem There exists in the art of charged particle irradiation therapy a need to know and/or control position, direction, energy, intensity, and/or cross-sectional area or shape of the charged particle beam relative to a tumor in a patient where a relative position of the tumor in the patient changes with time. The invention comprises a positively charged particle cancer treatment motion control system integrated with at least one imaging system. Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that are performed concurrently or in different order are illustrated in the figures to help improve understanding of embodiments of the present invention. The invention relates generally to at least one imaging system supported and moved by a gantry system also used to direct a charged particle beam, such as in treatment of a tumor of a patient. In one embodiment, a gantry positions both: (1) a section of a beam transport system, such as a terminal section, used to transport and direct positively charged particles to a tumor and (2) at least one imaging system. In one case, the imaging system is orientated on a same axis as the positively charged particle, such as at a different time through rotation of the gantry. In another case, the imaging system uses at least two crossing beamlines, each beamline coupled to a respective detector, to yield multiple views of the patient. In another case, one or more imaging subsystem yields a two-dimensional image of the patient, such as for position confirmation and/or as part of a set of images used to develop a three-dimensional image of the patient. In another embodiment, multiple linked control stations are used to control position of elements of a beam transport system, nozzle, and/or patient specific beam shaping element relative to a dynamically controlled patient position and/or an imaging surface, element, or system. In another embodiment, a tomography system is optionally used in combination with a charged particle cancer therapy system. Optionally and preferably, a common injector, accelerator, and beam transport system is used for both charged particle based tomographic imaging and charged particle cancer therapy. In one case, an output nozzle of the beam transport system is positioned with a gantry system while the gantry system and/or a patient support maintains a scintillation plate of the tomography system on the opposite side of the patient from the output nozzle. In another example, a charged particle state determination system, of a cancer therapy system or tomographic imaging system, uses one or more coated layers in conjunction with a scintillation detector or a tomographic imaging system at time of tumor and surrounding tissue sample mapping and/or at time of tumor treatment, such as to determine an input vector of the charged particle beam into a patient and/or an output vector of the charged particle beam from the patient. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system. The cancer therapy system uses the same injector, accelerator, and guided delivery system in delivering charged particles to the cancerous tumor. For example, the tomography apparatus and cancer therapy system use a common raster beam method and apparatus for treatment of solid cancers. More particularly, the invention comprises a multi-axis and/or multi-field raster beam charged particle accelerator used in: (1) tomography and (2) cancer therapy. Optionally, the system independently controls patient translation position, patient rotation position, two-dimensional beam trajectory, delivered radiation beam energy, delivered radiation beam intensity, beam velocity, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. The system operates in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus to deliver an effective and uniform dose of radiation to a tumor while distributing radiation striking healthy tissue. In another embodiment, a treatment delivery control system (TDCS) or main controller is used to control multiple aspects of the cancer therapy system, including one or more of: an imaging system, such as a CT or PET; a positioner, such as a couch or patient interface module; an injector or injection system; a radio-frequency quadrupole system; a ring accelerator or synchrotron; an extraction system; an irradiation plan; and a display system. The TDCS is preferably a control system for automated cancer therapy once the patient is positioned. The TDCS integrates output of one or more of the below described cancer therapy system elements with inputs of one or more of the below described cancer therapy system elements. More generally, the TDCS controls or manages input and/or output of imaging, an irradiation plan, and charged particle delivery. In yet another embodiment, one or more trays are inserted into the positively charged particle beam path, such as at or near the exit port of a gantry nozzle in close proximity to the patient. Each tray holds an insert, such as a patient specific insert for controlling the energy, focus depth, and/or shape of the charged particle beam. Examples of inserts include a range shifter, a compensator, an aperture, a ridge filter, and a blank. Optionally and preferably, each tray communicates a held and positioned insert to a main controller of the charged particle cancer therapy system. The trays optionally hold one or more of the imaging sheets configured to emit light upon transmission of the charged particle beam through a corresponding localized position of the one or more imaging sheets. Charged Particle Beam Therapy Throughout this document, a charged particle beam therapy system, such as a proton beam, hydrogen ion beam, or carbon ion beam, is described. Herein, the charged particle beam therapy system is described using a proton beam. However, the aspects taught and described in terms of a proton beam are not intended to be limiting to that of a proton beam and are illustrative of a charged particle beam system, a positively charged beam system, and/or a multiply charged particle beam system, such as C4+ or C6+. Any of the techniques described herein are equally applicable to any charged particle beam system. Referring now to FIG. 1A, a charged particle beam system 100 is illustrated. The charged particle beam preferably comprises a number of subsystems including any of: a main controller 110; an injection system 120; a synchrotron 130 that typically includes: (1) an accelerator system 132 and (2) an internal or connected extraction system 134; a beam transport system 135; a scanning/targeting/delivery system 140; a patient interface module 150; a display system 160; and/or an imaging system 170. An exemplary method of use of the charged particle beam system 100 is provided. The main controller 110 controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller 110 obtains an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 optionally controls the injection system 120 to inject a proton into a synchrotron 130. The synchrotron typically contains at least an accelerator system 132 and an extraction system 134. The main controller 110 preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The controller 110 also preferably controls targeting of the proton beam through the scanning/targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150, such as translational and rotational position of the patient, are preferably controlled by the main controller 110. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient. Herein, the main controller 110 refers to a single system controlling the charged particle beam system 100, to a single controller controlling a plurality of subsystems controlling the charged particle beam system 100, or to a plurality of individual controllers controlling one or more sub-systems of the charged particle beam system 100. Referring now to FIG. 13A, a first example of an integrated cancer treatment—imaging system 1300 is illustrated. In this example, the charged particle beam system 100 is illustrated with a treatment beam 269 directed to the tumor 720 of the patient 730 along the z-axis. Also illustrated is a set of imaging sources 1310, imaging system elements, and/or paths therefrom and a set of detectors 1320 corresponding to a respective element of the set of imaging sources 1310. Herein, the set of imaging sources 1310 are referred to as sources, but are optionally any point or element of the beam train prior to the tumor or a center point about which the gantry rotates. Hence, a given imaging source is optionally a dispersion element used to for cone beam. As illustrated, a first imaging source 1312 yields a first beam path 1332 and a second imaging source 1314 yields a second beam path 1334, where each path passes at least into the tumor 720 and optionally and preferably to a first detector array 1322 and a second detector array 1324, respectively, of the set of detectors 1320. Herein, the first beam path 1332 and the second beam path 1334 are illustrated as forming a ninety degree angle, which yields complementary images of the tumor 720 and/or the patient 730. However, the formed angle is optionally any angle from ten to three hundred fifty degrees. Herein, for clarity of presentation, the first beam path 1332 and the second beam path 1334 are illustrated as single lines, which optionally is an expanding, uniform diameter, or focusing beam. Herein, the first beam path 1332 and the second beam path 1334 are illustrated in transmission mode with their respective sources and detectors on opposite sides of the patient 730. However, a beam path from a source to a detector is optionally a scattered path and/or a diffuse reflectance path. Optionally, one or more detectors of the set of detectors 1320 are a single detector element, a line of detector elements, or preferably a two-dimensional detector array. Use of two two-dimensional detector arrays is referred to herein as a two-dimensional—two-dimensional imaging system or a 2D-2D imaging system. Still referring to FIG. 13A, the first imaging source 1312 and the second imaging source 1314 are illustrated at a first position and a second position, respectively. Each of the first imaging source 1312 and the second imaging source 1322 optionally: (1) maintain a fixed position; (2) provide the first beam path 1332 and the second beam path 1334, respectively, through the gantry 960, such as through a set of one or more holes or slits; (3) provide the first beam path 1332 and the second beam path 1334, respectively, off axis to a plane of movement of the nozzle system 760; (4) move with the gantry 960 as the gantry 960 rotates about at least a first axis; and/or (5) represent a narrow cross-diameter section of an expanding cone beam path. Still referring to FIG. 13A, the set of detectors 1320 are illustrated as coupling with respective elements of the set of sources 1310. Each member of the set of detectors 1320 optionally and preferably co-moves/and/or co-rotates with a respective member of the set of sources 1310. Thus, if the first imaging source 1312 is statically positioned, then the first detector 1322 is optionally and preferably statically positioned. Similarly, to facilitate imaging, if the first imaging source 1312 moves along a first arc as the gantry 960 moves, then the first detector 1322 optionally and preferably moves along the first arc or a second arc as the gantry 960 moves, where relative positions of the first imaging source 1312 on the first arc, a point that the gantry 960 moves about, and relative positions of the first detector 1322 along the second arc are constant. To facilitate the process, the detectors are optionally mechanically linked, such as with a first mechanical support 1342 to the gantry 960 in a manner that when the gantry 960 moves, the gantry moves both the source and the corresponding detector. Optionally, the source moves and a series of detectors, such as along the second arc, capture a set of images. Still referring to FIG. 13A, optionally and preferably, elements of the set of sources 1310 combined with elements of the set of detectors 1320 are used to collect a series of responses, such as one source and one detector yielding a detected intensity and preferably a set of detected intensities to form an image. For instance, the first imaging source 1312, such as a first X-ray source or first cone beam X-ray source, and the first detector 1322, such as an X-ray film, digital X-ray detector, or two-dimensional detector, yield a first X-ray image of the patient at a first time and a second X-ray image of the patient at a second time, such as to confirm a maintained location of a tumor or after movement of the gantry 760 or rotation of the patient 730. A set of n images using the first imaging source 1312 and the first detector 1322 collected as a function of movement of the gantry 760 and/or as a function of movement and/or rotation of the patient 730 are optionally and preferably combined to yield a three-dimensional image of the patient 730, such as a three-dimensional X-ray image of the patient 730, where n is a positive integer, such as greater than 1, 2, 3, 4, 5, 10, 15, 25, 50, or 100. The set of n images is optionally gathered as described in combination with images gathered using the second imaging source 1314, such as a second X-ray source or second cone beam X-ray source, and the second detector 1324, such as a second X-ray detector, where the use of two, or multiple, source/detector combinations are combined to yield images where the patient 730 has not moved between images as the two, or the multiple, images are optionally and preferably collected at the same time, such as with a difference in time of less than 0.01, 0.1, 1, or 5 seconds. Longer time differences are optionally used. Preferably the n two-dimensional images are collected as a function of rotation of the gantry 960 about the tumor and/or the patient and/or as a function of rotation of the patient 730 and the two-dimensional images of the X-ray cone beam are mathematically combined to form a three-dimensional image of the tumor 720 and/or the patient 730. Optionally, the first X-ray source and/or the second X-ray source is the source of X-rays that are divergent forming a cone through the tumor. A set of images collected as a function of rotation of the divergent X-ray cone around the tumor with a two-dimensional detector that detects the divergent X-rays transmitted through the tumor is used to form a three-dimensional X-ray of the tumor and of a portion of the patient, such as in X-ray computed tomography. Still referring to FIG. 13A, use of two imaging sources and two detectors set at ninety degrees to one another allows the gantry 960 or the patient 730 to rotate through half an angle required using only one imaging source and detector combination. A third imaging source/detector combination allows the three imaging source/detector combination to be set at sixty degree intervals allowing the imaging time to be cut to that of one-third that gantry 960 or patient 730 rotation required using a single imaging source-detector combination. Generally, n source-detector combinations reduces the time and/or the rotation requirements to 1/n. Further reduction is possible if the patient 730 and the gantry 960 rotate in opposite directions. Generally, the used of multiple source-detector combination of a given technology allow for a gantry that need not rotate through as large of an angle, with dramatic engineering benefits. Still referring to FIG. 13A, the set of sources 1310 and set of detectors 1320 optionally use more than one imaging technology. For example, a first imaging technology uses X-rays, a second used fluoroscopy, a third detects fluorescence, a fourth uses cone beam computed tomography or cone beam CT, and a fifth uses other electromagnetic waves. Optionally, the set of sources 1310 and the set of detectors 1320 use two or more sources and/or two or more detectors of a given imaging technology, such as described supra with two X-ray sources to n X-ray sources. Still referring to FIG. 13A, use of one or more of the set of sources 1310 and use of one or more of the set of detectors 1320 is optionally coupled with use of the positively charged particle tomography system described supra. As illustrated in FIG. 13A, the positively charged particle tomography system uses a second mechanical support 1343 to co-rotate the scintillation plate 710 with the gantry 960, as well as to co-rotate an optional sheet, such as the first sheet 760 and/or the fourth sheet 790. Referring now to FIG. 1B, an example of a charged particle cancer therapy system 100 is provided. A main controller receives input from one, two, three, or four of a respiration monitoring and/or controlling controller 180, a beam controller 185, a rotation controller 147, and/or a timing to a time period in a respiration cycle controller 148. The beam controller 185 preferably includes one or more or a beam energy controller 182, the beam intensity controller 340, a beam velocity controller 186, and/or a horizontal/vertical beam positioning controller 188. The main controller 110 controls any element of the injection system 120; the synchrotron 130; the scanning/targeting/delivery system 140; the patient interface module 150; the display system 160; and/or the imaging system 170. For example, the respiration monitoring/controlling controller 180 controls any element or method associated with the respiration of the patient; the beam controller 185 controls any of the elements controlling acceleration and/or extraction of the charged particle beam; the rotation controller 147 controls any element associated with rotation of the patient 830 or gantry; and the timing to a period in respiration cycle controller 148 controls any aspects affecting delivery time of the charged particle beam to the patient. As a further example, the beam controller 185 optionally controls any magnetic and/or electric field about any magnet in the charged particle cancer therapy system 100. One or more beam state sensors 190 sense position, direction, intensity, and/or energy of the charged particles at one or more positions in the charged particle beam path. A tomography system 700, described infra, is optionally used to monitor intensity and/or position of the charged particle beam. Referring now to FIG. 2, an illustrative exemplary embodiment of one version of the charged particle beam system 100 is provided. The number, position, and described type of components is illustrative and non-limiting in nature. In the illustrated embodiment, the injection system 120 or ion source or charged particle beam source generates protons. The injection system 120 optionally includes one or more of: a negative ion beam source, an ion beam focusing lens, and a tandem accelerator. The protons are delivered into a vacuum tube that runs into, through, and out of the synchrotron. The generated protons are delivered along an initial path 262. Focusing magnets 230, such as quadrupole magnets or injection quadrupole magnets, are used to focus the proton beam path. A quadrupole magnet is a focusing magnet. An injector bending magnet 232 bends the proton beam toward a plane of the synchrotron 130. The focused protons having an initial energy are introduced into an injector magnet 240, which is preferably an injection Lamberson magnet. Typically, the initial beam path 262 is along an axis off of, such as above, a circulating plane of the synchrotron 130. The injector bending magnet 232 and injector magnet 240 combine to move the protons into the synchrotron 130. Main bending magnets, dipole magnets, turning magnets, or circulating magnets 250 are used to turn the protons along a circulating beam path 264. A dipole magnet is a bending magnet. The main bending magnets 250 bend the initial beam path 262 into a circulating beam path 264. In this example, the main bending magnets 250 or circulating magnets are represented as four sets of four magnets to maintain the circulating beam path 264 into a stable circulating beam path. However, any number of magnets or sets of magnets are optionally used to move the protons around a single orbit in the circulation process. The protons pass through an accelerator 270. The accelerator accelerates the protons in the circulating beam path 264. As the protons are accelerated, the fields applied by the magnets are increased. Particularly, the speed of the protons achieved by the accelerator 270 are synchronized with magnetic fields of the main bending magnets 250 or circulating magnets to maintain stable circulation of the protons about a central point or region 280 of the synchrotron. At separate points in time the accelerator 270/main bending magnet 250 combination is used to accelerate and/or decelerate the circulating protons while maintaining the protons in the circulating path or orbit. An extraction element of an inflector/deflector system is used in combination with a Lamberson extraction magnet 292 to remove protons from their circulating beam path 264 within the synchrotron 130. One example of a deflector component is a Lamberson magnet. Typically the deflector moves the protons from the circulating plane to an axis off of the circulating plane, such as above the circulating plane. Extracted protons are preferably directed and/or focused using an extraction bending magnet 237 and extraction focusing magnets 235, such as quadrupole magnets along a positively charged particle beam transport path 268 in a beam transport system 135, such as a beam path or proton beam path, into the scanning/targeting/delivery system 140. Two components of a scanning system 140 or targeting system typically include a first axis control 142, such as a vertical control, and a second axis control 144, such as a horizontal control. In one embodiment, the first axis control 142 allows for about 100 mm of vertical or y-axis scanning of the proton beam 268 and the second axis control 144 allows for about 700 mm of horizontal or x-axis scanning of the proton beam 268. A nozzle system 146 is used for imaging the proton beam, for defining shape of the proton beam, and/or as a vacuum barrier between the low pressure beam path of the synchrotron and the atmosphere. Protons are delivered with control to the patient interface module 150 and to a tumor of a patient. All of the above listed elements are optional and may be used in various permutations and combinations. Proton Beam Extraction Referring now to FIG. 3, both: (1) an exemplary proton beam extraction system 300 from the synchrotron 130 and (2) a charged particle beam intensity control system 305 are illustrated. For clarity, FIG. 3 removes elements represented in FIG. 2, such as the turning magnets, which allows for greater clarity of presentation of the proton beam path as a function of time. Generally, protons are extracted from the synchrotron 130 by slowing the protons. As described, supra, the protons were initially accelerated in a circulating path, which is maintained with a plurality of main bending magnets 250. The circulating path is referred to herein as an original central beamline 264. The protons repeatedly cycle around a central point in the synchrotron 280. The proton path traverses through a radio frequency (RF) cavity system 310. To initiate extraction, an RF field is applied across a first blade 312 and a second blade 314, in the RF cavity system 310. The first blade 312 and second blade 314 are referred to herein as a first pair of blades. In the proton extraction process, an RF voltage is applied across the first pair of blades, where the first blade 312 of the first pair of blades is on one side of the circulating proton beam path 264 and the second blade 314 of the first pair of blades is on an opposite side of the circulating proton beam path 264. The applied RF field applies energy to the circulating charged-particle beam. The applied RF field alters the orbiting or circulating beam path slightly of the protons from the original central beamline 264 to an altered circulating beam path 265. Upon a second pass of the protons through the RF cavity system, the RF field further moves the protons off of the original proton beamline 264. For example, if the original beamline is considered as a circular path, then the altered beamline is slightly elliptical. The frequency of the applied RF field is timed to apply outward or inward movement to a given band of protons circulating in the synchrotron accelerator. Orbits of the protons are slightly more off axis compared to the original circulating beam path 264. Successive passes of the protons through the RF cavity system are forced further and further from the original central beamline 264 by altering the direction and/or intensity of the RF field with each successive pass of the proton beam through the RF field. Timing of application of the RF field and/or frequency of the RF field is related to the circulating charged particles circulation pathlength in the synchrotron 130 and the velocity of the charged particles so that the applied RF field has a period, with a peak-to-peak time period, equal to a period of time of beam circulation in the synchrotron 130 about the center 280 or an integer multiple of the time period of beam circulation about the center 280 of the synchrotron 130. Alternatively, the time period of beam circulation about the center 280 of the synchrotron 130 is an integer multiple of the RF period time. The RF period is optionally used to calculated the velocity of the charged particles, which relates directly to the energy of the circulating charged particles. The RF voltage is frequency modulated at a frequency about equal to the period of one proton cycling around the synchrotron for one revolution or at a frequency than is an integral multiplier of the period of one proton cycling about the synchrotron. The applied RF frequency modulated voltage excites a betatron oscillation. For example, the oscillation is a sine wave motion of the protons. The process of timing the RF field to a given proton beam within the RF cavity system is repeated thousands of times with each successive pass of the protons being moved approximately one micrometer further off of the original central beamline 264. For clarity, the approximately 1000 changing beam paths with each successive path of a given band of protons through the RF field are illustrated as the altered beam path 265. The RF time period is process is known, thus energy of the charged particles at time of hitting the extraction material or material 330, described infra, is known. With a sufficient sine wave betatron amplitude, the altered circulating beam path 265 touches and/or traverses a material 330, such as a foil or a sheet of foil. The foil is preferably a lightweight material, such as beryllium, a lithium hydride, a carbon sheet, or a material having low nuclear charge components. Herein, a material of low nuclear charge is a material composed of atoms consisting essentially of atoms having six or fewer protons. The foil is preferably about 10 to 150 microns thick, is more preferably about 30 to 100 microns thick, and is still more preferably about 40 to 60 microns thick. In one example, the foil is beryllium with a thickness of about 50 microns. When the protons traverse through the foil, energy of the protons is lost and the speed of the protons is reduced. Typically, a current is also generated, described infra. Protons moving at the slower speed travel in the synchrotron with a reduced radius of curvature 266 compared to either the original central beamline 264 or the altered circulating path 265. The reduced radius of curvature 266 path is also referred to herein as a path having a smaller diameter of trajectory or a path having protons with reduced energy. The reduced radius of curvature 266 is typically about two millimeters less than a radius of curvature of the last pass of the protons along the altered proton beam path 265. The thickness of the material 330 is optionally adjusted to create a change in the radius of curvature, such as about ½, 1, 2, 3, or 4 mm less than the last pass of the protons 265 or original radius of curvature 264. The reduction in velocity of the charged particles transmitting through the material 330 is calculable, such as by using the pathlength of the betatron oscillating charged particle beam through the material 330 and/or using the density of the material 330. Protons moving with the smaller radius of curvature travel between a second pair of blades. In one case, the second pair of blades is physically distinct and/or is separated from the first pair of blades. In a second case, one of the first pair of blades is also a member of the second pair of blades. For example, the second pair of blades is the second blade 314 and a third blade 316 in the RF cavity system 310. A high voltage DC signal, such as about 1 to 5 kV, is then applied across the second pair of blades, which directs the protons out of the synchrotron through an extraction magnet 292, such as a Lamberson extraction magnet, into a transport path 268. Control of acceleration of the charged particle beam path in the synchrotron with the accelerator and/or applied fields of the turning magnets in combination with the above described extraction system allows for control of the intensity of the extracted proton beam, where intensity is a proton flux per unit time or the number of protons extracted as a function of time. For example, when a current is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In another embodiment, instead of moving the charged particles to the material 330, the material 330 is mechanically moved to the circulating charged particles. Particularly, the material 330 is mechanically or electromechanically translated into the path of the circulating charged particles to induce the extraction process, described supra. In this case, the velocity or energy of the circulating charged particle beam is calculable using the pathlength of the beam path about the center 280 of the synchrotron 130 and from the force applied by the bending magnets 250. In either case, because the extraction system does not depend on any change in magnetic field properties, it allows the synchrotron to continue to operate in acceleration or deceleration mode during the extraction process. Stated differently, the extraction process does not interfere with synchrotron acceleration. In stark contrast, traditional extraction systems introduce a new magnetic field, such as via a hexapole, during the extraction process. More particularly, traditional synchrotrons have a magnet, such as a hexapole magnet, that is off during an acceleration stage. During the extraction phase, the hexapole magnetic field is introduced to the circulating path of the synchrotron. The introduction of the magnetic field necessitates two distinct modes, an acceleration mode and an extraction mode, which are mutually exclusive in time. The herein described system allows for acceleration and/or deceleration of the proton during the extraction step and tumor treatment without the use of a newly introduced magnetic field, such as by a hexapole magnet. Charged Particle Beam Intensity Control Control of applied field, such as a radio-frequency (RF) field, frequency and magnitude in the RF cavity system 310 allows for intensity control of the extracted proton beam, where intensity is extracted proton flux per unit time or the number of protons extracted as a function of time. Still referring FIG. 3, the intensity control system 305 is further described. In this example, an intensity control feedback loop is added to the extraction system, described supra. When protons in the proton beam hit the material 330 electrons are given off from the material 330 resulting in a current. The resulting current is converted to a voltage and is used as part of an ion beam intensity monitoring system or as part of an ion beam feedback loop for controlling beam intensity. The voltage is optionally measured and sent to the main controller 110 or to an intensity controller subsystem 340, which is preferably in communication or under the direction of the main controller 110. More particularly, when protons in the charged particle beam path pass through the material 330, some of the protons lose a small fraction of their energy, such as about one-tenth of a percent, which results in a secondary electron. That is, protons in the charged particle beam push some electrons when passing through material 330 giving the electrons enough energy to cause secondary emission. The resulting electron flow results in a current or signal that is proportional to the number of protons going through the target or extraction material 330. The resulting current is preferably converted to voltage and amplified. The resulting signal is referred to as a measured intensity signal. The amplified signal or measured intensity signal resulting from the protons passing through the material 330 is optionally used in monitoring the intensity of the extracted protons and is preferably used in controlling the intensity of the extracted protons. For example, the measured intensity signal is compared to a goal signal, which is predetermined in an irradiation of the tumor plan. The difference between the measured intensity signal and the planned for goal signal is calculated. The difference is used as a control to the RF generator. Hence, the measured flow of current resulting from the protons passing through the material 330 is used as a control in the RF generator to increase or decrease the number of protons undergoing betatron oscillation and striking the material 330. Hence, the voltage determined off of the material 330 is used as a measure of the orbital path and is used as a feedback control to control the RF cavity system. In one example, the intensity controller subsystem 340 preferably additionally receives input from: (1) a detector 350, which provides a reading of the actual intensity of the proton beam and/or (2) an irradiation plan 360. The irradiation plan provides the desired intensity of the proton beam for each x, y, energy, and/or rotational position of the patient/tumor as a function of time. Thus, the intensity controller 340 receives the desired intensity from the irradiation plan 350, the actual intensity from the detector 350 and/or a measure of intensity from the material 330, and adjusts the amplitude and/or the duration of application of the applied radio-frequency field in the RF cavity system 310 to yield an intensity of the proton beam that matches the desired intensity from the irradiation plan 360. As described, supra, the protons striking the material 330 is a step in the extraction of the protons from the synchrotron 130. Hence, the measured intensity signal is used to change the number of protons per unit time being extracted, which is referred to as intensity of the proton beam. The intensity of the proton beam is thus under algorithm control. Further, the intensity of the proton beam is controlled separately from the velocity of the protons in the synchrotron 130. Hence, intensity of the protons extracted and the energy of the protons extracted are independently variable. Still further, the intensity of the extracted protons is controllably variable while scanning the charged particles beam in the tumor from one voxel to an adjacent voxel as a separate hexapole and separated time period from acceleration and/or treatment is not required, as described supra. For example, protons initially move at an equilibrium trajectory in the synchrotron 130. An RF field is used to excite or move the protons into a betatron oscillation. In one case, the frequency of the protons orbit is about 10 MHz. In one example, in about one millisecond or after about 10,000 orbits, the first protons hit an outer edge of the target material 130. The specific frequency is dependent upon the period of the orbit. Upon hitting the material 130, the protons push electrons through the foil to produce a current. The current is converted to voltage and amplified to yield a measured intensity signal. The measured intensity signal is used as a feedback input to control the applied RF magnitude or RF field. An energy beam sensor, described infra, is optionally used as a feedback control to the RF field frequency or RF field of the RF field extraction system 310 to dynamically control, modify, and/or alter the delivered charge particle beam energy, such as in a continuous pencil beam scanning system operating to treat tumor voxels without alternating between an extraction phase and a treatment phase. Preferably, the measured intensity signal is compared to a target signal and a measure of the difference between the measured intensity signal and target signal is used to adjust the applied RF field in the RF cavity system 310 in the extraction system to control the intensity of the protons in the extraction step. Stated again, the signal resulting from the protons striking and/or passing through the material 130 is used as an input in RF field modulation. An increase in the magnitude of the RF modulation results in protons hitting the foil or material 130 sooner. By increasing the RF, more protons are pushed into the foil, which results in an increased intensity, or more protons per unit time, of protons extracted from the synchrotron 130. In another example, a detector 350 external to the synchrotron 130 is used to determine the flux of protons extracted from the synchrotron and a signal from the external detector is used to alter the RF field, RF intensity, RF amplitude, and/or RF modulation in the RF cavity system 310. Here the external detector generates an external signal, which is used in a manner similar to the measured intensity signal, described in the preceding paragraphs. Preferably, an algorithm or irradiation plan 360 is used as an input to the intensity controller 340, which controls the RF field modulation by directing the RF signal in the betatron oscillation generation in the RF cavity system 310. The irradiation plan 360 preferably includes the desired intensity of the charged particle beam as a function of time and/or energy of the charged particle beam as a function of time, for each patient rotation position, and/or for each x-, y-position of the charged particle beam. In yet another example, when a current from material 330 resulting from protons passing through or hitting material is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In still yet another embodiment, intensity modulation of the extracted proton beam is controlled by the main controller 110. The main controller 110 optionally and/or additionally controls timing of extraction of the charged particle beam and energy of the extracted proton beam. The benefits of the system include a multi-dimensional scanning system. Particularly, the system allows independence in: (1) energy of the protons extracted and (2) intensity of the protons extracted. That is, energy of the protons extracted is controlled by an energy control system and an intensity control system controls the intensity of the extracted protons. The energy control system and intensity control system are optionally independently controlled. Preferably, the main controller 110 controls the energy control system and the main controller 110 simultaneously controls the intensity control system to yield an extracted proton beam with controlled energy and controlled intensity where the controlled energy and controlled intensity are independently variable and/or continually available as a separate extraction phase and acceleration phase are not required, as described supra. Thus the irradiation spot hitting the tumor is under independent control of: time; energy; intensity; x-axis position, where the x-axis represents horizontal movement of the proton beam relative to the patient, and y-axis position, where the y-axis represents vertical movement of the proton beam relative to the patient. In addition, the patient is optionally independently translated and/or rotated relative to a translational axis of the proton beam at the same time. Beam Transport The beam transport system 135 is used to move the charged particles from the accelerator to the patient, such as via a nozzle in a gantry, described infra. Charged Particle Energy The beam transport system 135 optionally includes means for determining an energy of the charged particles in the charged particle beam. For example, an energy of the charged particle beam is determined via calculation, such as via equation 1, using knowledge of a magnet geometry and applied magnetic field to determine mass and/or energy. Referring now to equation 1, for a known magnet geometry, charge, q, and magnetic field, B, the Larmor radius, ρL, or magnet bend radius is defined as: ρ L = v ⊥ Ω c = 2 Em qB ( eq . 1 ) where: ν⊥ is the ion velocity perpendicular to the magnetic field, Ωc is the cyclotron frequency, q is the charge of the ion, B is the magnetic field, m is the mass of the charge particle, and E is the charged particle energy. Solving for the charged particle energy yields equation 2. E = ( ρ L qB ) 2 2 m ( eq . 2 ) Thus, an energy of the charged particle in the charged particle beam in the beam transport system 135 is calculable from the know magnet geometry, known or measured magnetic field, charged particle mass, charged particle charge, and the known magnet bend radius, which is proportional to and/or equivalent to the Larmor radius. Nozzle After extraction from the synchrotron 130 and transport of the charged particle beam along the proton beam path 268 in the beam transport system 135, the charged particle beam exits through the nozzle system 146. In one example, the nozzle system includes a nozzle foil covering an end of the nozzle system 146 or a cross-sectional area within the nozzle system forming a vacuum seal. The nozzle system includes a nozzle that expands in x/y-cross-sectional area along the z-axis of the proton beam path 268 to allow the proton beam 268 to be scanned along the x-axis and y-axis by the vertical control element and horizontal control element, respectively. The nozzle foil is preferably mechanically supported by the outer edges of an exit port of the nozzle 146. An example of a nozzle foil is a sheet of about 0.1 inch thick aluminum foil. Generally, the nozzle foil separates atmosphere pressures on the patient side of the nozzle foil from the low pressure region, such as about 10−5 to 10−7 torr region, on the synchrotron 130 side of the nozzle foil. The low pressure region is maintained to reduce scattering of the circulating charged particle beam in the synchrotron. Herein, the exit foil of the nozzle is optionally the first sheet 760 of the charged particle beam state determination system 750, described infra. Charged Particle Control Referring now to FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, and FIG. 6B, a charged particle beam control system is described where one or more patient specific beam control assemblies are removably inserted into the charged particle beam path proximate the nozzle of the charged particle cancer therapy system 100, where the patient specific beam control assemblies adjust the beam energy, diameter, cross-sectional shape, focal point, and/or beam state of the charged particle beam to properly couple energy of the charged particle beam to the individual's specific tumor. Beam Control Tray Referring now to FIG. 4A and FIG. 4B, a beam control tray assembly 400 is illustrated in a top view and side view, respectively. The beam control tray assembly 400 optionally comprises any of a tray frame 410, a tray aperture 412, a tray handle 420, a tray connector/communicator 430, and means for holding a patient specific tray insert 510, described infra. Generally, the beam control tray assembly 400 is used to: (1) hold the patient specific tray insert 510 in a rigid location relative to the beam control tray 400, (2) electronically identify the held patient specific tray insert 510 to the main controller 110, and (3) removably insert the patient specific tray insert 510 into an accurate and precise fixed location relative to the charged particle beam, such as the proton beam path 268 at the nozzle of the charged particle cancer therapy system 100. For clarity of presentation and without loss of generality, the means for holding the patient specific tray insert 510 in the tray frame 410 of the beam control tray assembly 400 is illustrated as a set of recessed set screws 415. However, the means for holding the patient specific tray insert 510 relative to the rest of the beam control tray assembly 400 is optionally any mechanical and/or electromechanical positioning element, such as a latch, clamp, fastener, clip, slide, strap, or the like. Generally, the means for holding the patient specific tray insert 510 in the beam control tray 400 fixes the tray insert and tray frame relative to one another even when rotated along and/or around multiple axes, such as when attached to a charged particle cancer therapy system 100 dynamic gantry nozzle 610 or gantry nozzle, which is an optional element of the nozzle system 146, that moves in three-dimensional space relative to a fixed point in the beamline, proton beam path 268, and/or a given patient position. As illustrated in FIG. 4A and FIG. 4B, the recessed set screws 415 fix the patient specific tray insert 510 into the aperture 412 of the tray frame 410. The tray frame 410 is illustrated as circumferentially surrounding the patient specific tray insert 510, which aids in structural stability of the beam control tray assembly 400. However, generally the tray frame 410 is of any geometry that forms a stable beam control tray assembly 400. Still referring to FIG. 4A and now referring to FIG. 5 and FIG. 6A, the optional tray handle 420 is used to manually insert/retract the beam control tray assembly 400 into a receiving element of the gantry nozzle or dynamic gantry nozzle 610. While the beam control tray assembly 400 is optionally inserted into the charged particle beam path 268 at any point after extraction from the synchrotron 130, the beam control tray assembly 400 is preferably inserted into the positively charged particle beam proximate the dynamic gantry nozzle 610 as control of the beam shape is preferably done with little space for the beam shape to defocus before striking the tumor. Optionally, insertion and/or retraction of the beam control tray assembly 400 is semi-automated, such as in a manner of a digital-video disk player receiving a digital-video disk, with a selected auto load and/or a selected auto unload feature. Patient Specific Tray Insert Referring again to FIG. 5, a system of assembling trays 500 is described. The beam control tray assembly 400 optionally and preferably has interchangeable patient specific tray inserts 510, such as a range shifter insert 511, a patient specific ridge filter insert 512, an aperture insert 513, a compensator insert 514, or a blank insert 515. As described, supra, any of the range shifter insert 511, the patient specific ridge filter insert 512, the aperture insert 513, the compensator insert 514, or the blank insert 515 after insertion into the tray frame 410 are inserted as the beam control tray assembly 400 into the positively charged particle beam path 268, such as proximate the dynamic gantry nozzle 610. Still referring to FIG. 5, the patient specific tray inserts 510 are further described. The patient specific tray inserts comprise a combination of any of: (1) a standardized beam control insert and (2) a patient specific beam control insert. For example, the range shifter insert or 511 or compensator insert 514 used to control the depth of penetration of the charged particle beam into the patient is optionally: (a) a standard thickness of a beam slowing material, such as a first thickness of Lucite, (b) one member of a set of members of varying thicknesses and/or densities where each member of the set of members slows the charged particles in the beam path by a known amount, or (c) is a material with a density and thickness designed to slow the charged particles by a customized amount for the individual patient being treated, based on the depth of the individual's tumor in the tissue, the thickness of intervening tissue, and/or the density of intervening bone/tissue. Similarly, the ridge filter insert 512 used to change the focal point or shape of the beam as a function of depth is optionally: (1) selected from a set of ridge filters where different members of the set of ridge filters yield different focal depths or (2) customized for treatment of the individual's tumor based on position of the tumor in the tissue of the individual. Similarly, the aperture insert is: (1) optionally selected from a set of aperture shapes or (2) is a customized individual aperture insert 513 designed for the specific shape of the individual's tumor. The blank insert 515 is an open slot, but serves the purpose of identifying slot occupancy, as described infra. Slot Occupancy/Identification Referring again to FIG. 4A, FIG. 4B, and FIG. 5, occupancy and identification of the particular patient specific tray insert 510 into the beam control tray assembly 400 is described. Generally, the beam control tray assembly 400 optionally contains means for identifying, to the main controller 110 and/or a treatment delivery control system described infra, the specific patient tray insert 510 and its location in the charged particle beam path 268. First, the particular tray insert is optionally labeled and/or communicated to the beam control tray assembly 400 or directly to the main controller 110. Second, the beam control tray assembly 400 optionally communicates the tray type and/or tray insert to the main controller 110. In various embodiments, communication of the particular tray insert to the main controller 110 is performed: (1) directly from the tray insert, (2) from the tray insert 510 to the tray assembly 400 and subsequently to the main controller 110, and/or (3) directly from the tray assembly 400. Generally, communication is performed wirelessly and/or via an established electromechanical link. Identification is optionally performed using a radio-frequency identification label, use of a barcode, or the like, and/or via operator input. Examples are provided to further clarify identification of the patient specific tray insert 510 in a given beam control tray assembly 400 to the main controller. In a first example, one or more of the patient specific tray inserts 510, such as the range shifter insert 511, the patient specific ridge filter insert 512, the aperture insert 513, the compensator insert 514, or the blank insert 515 include an identifier 520 and/or and a first electromechanical identifier plug 530. The identifier 520 is optionally a label, a radio-frequency identification tag, a barcode, a 2-dimensional bar-code, a matrix-code, or the like. The first electromechanical identifier plug 530 optionally includes memory programmed with the particular patient specific tray insert information and a connector used to communicate the information to the beam control tray assembly 400 and/or to the main controller 110. As illustrated in FIG. 5, the first electromechanical identifier plug 530 affixed to the patient specific tray insert 510 plugs into a second electromechanical identifier plug, such as the tray connector/communicator 430, of the beam control tray assembly 400, which is described infra. In a second example, the beam control tray assembly 400 uses the second electromechanical identifier plug to send occupancy, position, and/or identification information related to the type of tray insert or the patient specific tray insert 510 associated with the beam control tray assembly to the main controller 110. For example, a first tray assembly is configured with a first tray insert and a second tray assembly is configured with a second tray insert. The first tray assembly sends information to the main controller 110 that the first tray assembly holds the first tray insert, such as a range shifter, and the second tray assembly sends information to the main controller 110 that the second tray assembly holds the second tray insert, such as an aperture. The second electromechanical identifier plug optionally contains programmable memory for the operator to input the specific tray insert type, a selection switch for the operator to select the tray insert type, and/or an electromechanical connection to the main controller. The second electromechanical identifier plug associated with the beam control tray assembly 400 is optionally used without use of the first electromechanical identifier plug 530 associated with the tray insert 510. In a third example, one type of tray connector/communicator 430 is used for each type of patient specific tray insert 510. For example, a first connector/communicator type is used for holding a range shifter insert 511, while a second, third, fourth, and fifth connector/communicator type is used for trays respectively holding a patient specific ridge filter insert 512, an aperture insert 513, a compensator insert 514, or a blank insert 515. In one case, the tray communicates tray type with the main controller. In a second case, the tray communicates patient specific tray insert information with the main controller, such as an aperture identifier custom built for the individual patient being treated. Tray Insertion/Coupling Referring now to FIG. 6A and FIG. 6B a beam control insertion process 600 is described. The beam control insertion process 600 comprises: (1) insertion of the beam control tray assembly 400 and the associated patient specific tray insert 510 into the charged particle beam path 268 and/or dynamic gantry nozzle 610, such as into a tray assembly receiver 620 and (2) an optional partial or total retraction of beam of the tray assembly receiver 620 into the dynamic gantry nozzle 610. Referring now to FIG. 6A, insertion of one or more of the beam control tray assemblies 400 and the associated patient specific tray inserts 510 into the dynamic gantry nozzle 610 is further described. In FIG. 6A, three beam control tray assemblies, of a possible n tray assemblies, are illustrated, a first tray assembly 402, a second tray assembly 404, and a third tray assembly 406, where n is a positive integer of 1, 2, 3, 4, 5 or more. As illustrated, the first tray assembly 402 slides into a first receiving slot 403, the second tray assembly 404 slides into a second receiving slot 405, and the third tray assembly 406 slides into a third receiving slot 407. Generally, any tray optionally inserts into any slot or tray types are limited to particular slots through use of a mechanical, physical, positional, and/or steric constraints, such as a first tray type configured for a first insert type having a first size and a second tray type configured for a second insert type having a second distinct size at least ten percent different from the first size. Still referring to FIG. 6A, identification of individual tray inserts inserted into individual receiving slots is further described. As illustrated, sliding the first tray assembly 402 into the first receiving slot 403 connects the associated electromechanical connector/communicator 430 of the first tray assembly 402 to a first receptor 626. The electromechanical connector/communicator 430 of the first tray assembly communicates tray insert information of the first beam control tray assembly to the main controller 110 via the first receptor 626. Similarly, sliding the second tray assembly 404 into the second receiving slot 405 connects the associated electromechanical connector/communicator 430 of the second tray assembly 404 into a second receptor 627, which links communication of the associated electromechanical connector/communicator 430 with the main controller 110 via the second receptor 627, while a third receptor 628 connects to the electromechanical connected placed into the third slot 407. The non-wireless/direct connection is preferred due to the high radiation levels within the treatment room and the high shielding of the treatment room, which both hinder wireless communication. The connection of the communicator and the receptor is optionally of any configuration and/or orientation. Tray Receiver Assembly Retraction Referring again to FIG. 6A and FIG. 6B, retraction of the tray receiver assembly 620 relative to a nozzle end 612 of the dynamic gantry nozzle 610 is described. The tray receiver assembly 620 comprises a framework to hold one or more of the beam control tray assemblies 400 in one or more slots, such as through use of a first tray receiver assembly side 622 through which the beam control tray assemblies 400 are inserted and/or through use of a second tray receiver assembly side 624 used as a backstop, as illustrated holding the plugin receptors configured to receive associated tray connector/communicators 430, such as the first, second, and third receptors 626, 627, 628. Optionally, the tray receiver assembly 620 retracts partially or completely into the dynamic gantry nozzle 610 using a retraction mechanism 660 configured to alternatingly retract and extend the tray receiver assembly 620 relative to a nozzle end 612 of the gantry nozzle 610, such as along a first retraction track 662 and a second retraction track 664 using one or more motors and computer control. Optionally the tray receiver assembly 620 is partially or fully retracted when moving the gantry, nozzle, and/or gantry nozzle 610 to avoid physical constraints of movement, such as potential collision with another object in the patient treatment room. For clarity of presentation and without loss of generality, several examples of loading patient specific tray inserts into tray assemblies with subsequent insertion into an positively charged particle beam path proximate a gantry nozzle 610 are provided. In a first example, a single beam control tray assembly 400 is used to control the charged particle beam 268 in the charged particle cancer therapy system 100. In this example, a patient specific range shifter insert 511, which is custom fabricated for a patient, is loaded into a patient specific tray insert 510 to form a first tray assembly 402, where the first tray assembly 402 is loaded into the third receptor 628, which is fully retracted into the gantry nozzle 610. In a second example, two beam control assemblies 400 are used to control the charged particle beam 268 in the charged particle cancer therapy system 100. In this example, a patient specific ridge filter 512 is loaded into a first tray assembly 402, which is loaded into the second receptor 627 and a patient specific aperture 513 is loaded into a second tray assembly 404, which is loaded into the first receptor 626 and the two associated tray connector/communicators 430 using the first receptor 626 and second receptor 627 communicate to the main controller 110 the patient specific tray inserts 510. The tray receiver assembly 620 is subsequently retracted one slot so that the patient specific ridge filter 512 and the patient specific aperture reside outside of and at the nozzle end 612 of the gantry nozzle 610. In a third example, three beam control tray assemblies 400 are used, such as a range shifter 511 in a first tray inserted into the first receiving slot 403, a compensator in a second tray inserted into the second receiving slot 405, and an aperture in a third tray inserted into the third receiving slot 407. Generally, any patient specific tray insert 510 is inserted into a tray frame 410 to form a beam control tray assembly 400 inserted into any slot of the tray receiver assembly 620 and the tray assembly is not retracted or retracted any distance into the gantry nozzle 610. Tomography/Beam State In one embodiment, the charged particle tomography apparatus is used to image a tumor in a patient. As current beam position determination/verification is used in both tomography and cancer therapy treatment, for clarity of presentation and without limitation beam state determination is also addressed in this section. However, beam state determination is optionally used separately and without tomography. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system using common elements. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system that are part of the cancer therapy system, described supra. In various examples, the tomography imaging system is optionally simultaneously operational with a charged particle cancer therapy system using common elements, allows tomographic imaging with rotation of the patient, is operational on a patient in an upright, semi-upright, and/or horizontal position, is simultaneously operational with X-ray imaging, and/or allows use of adaptive charged particle cancer therapy. Further, the common tomography and cancer therapy apparatus elements are optionally operational in a multi-axis and/or multi-field raster beam mode. In conventional medical X-ray tomography, a sectional image through a body is made by moving one or both of an X-ray source and the X-ray film in opposite directions during the exposure. By modifying the direction and extent of the movement, operators can select different focal planes, which contain the structures of interest. More modern variations of tomography involve gathering projection data from multiple directions by moving the X-ray source and feeding the data into a tomographic reconstruction software algorithm processed by a computer. Herein, in stark contrast to known methods, the radiation source is a charged particle, such as a proton ion beam or a carbon ion beam. A proton beam is used herein to describe the tomography system, but the description applies to a heavier ion beam, such as a carbon ion beam. Further, in stark contrast to known techniques, herein the radiation source is preferably stationary while the patient is rotated. Referring now to FIG. 7, an example of a tomography apparatus is described and an example of a beam state determination is described. In this example, the tomography system 700 uses elements in common with the charged particle beam system 100, including elements of one or more of the injection system 120, accelerator 130, targeting/delivery system 140, patient interface module 150, display system 160, and/or imaging system 170, such as the X-ray imaging system. One or more scintillation plates, such as a scintillating plastic, are used to measure energy, intensity, and/or position of the charged particle beam. For instance, a scintillation plate 710 is positioned behind the patient 730 relative to the targeting/delivery system 140 elements, which is optionally used to measure intensity and/or position of the charged particle beam after transmitting through the patient. Optionally, a second scintillation plate or a charged particle induced photon emitting sheet, described infra, is positioned prior to the patient 730 relative to the targeting/delivery system 140 elements, which is optionally used to measure incident intensity and/or position of the charged particle beam prior to transmitting through the patient. The charged particle beam system 100 as described has proven operation at up to and including 330 MeV, which is sufficient to send protons through the body and into contact with the scintillation material. Particularly, 250 MeV to 330 MeV are used to pass the beam through a standard sized patient with a standard sized pathlength, such as through the chest. The intensity or count of protons hitting the plate as a function of position is used to create an image. The velocity or energy of the proton hitting the scintillation plate is also used in creation of an image of the tumor 720 and/or an image of the patient 730. The patient 730 is rotated about the y-axis and a new image is collected. Preferably, a new image is collected with about every one degree of rotation of the patient resulting in about 360 images that are combined into a tomogram using tomographic reconstruction software. The tomographic reconstruction software uses overlapping rotationally varied images in the reconstruction. Optionally, a new image is collected at about every 2, 3, 4, 5, 10, 15, 30, or 45 degrees of rotation of the patient. In one embodiment, a tomogram or an individual tomogram section image is collected at about the same time as cancer therapy occurs using the charged particle beam system 100. For example, a tomogram is collected and cancer therapy is subsequently performed: without the patient moving from the positioning systems, such as in a semi-vertical partial immobilization system, a sitting partial immobilization system, or the a laying position. In a second example, an individual tomogram slice is collected using a first cycle of the accelerator 130 and using a following cycle of the accelerator 130, the tumor 720 is irradiated, such as within about 1, 2, 5, 10, 15 or 30 seconds. In a third case, about 2, 3, 4, or 5 tomogram slices are collected using 1, 2, 3, 4, or more rotation positions of the patient 730 within about 5, 10, 15, 30, or 60 seconds of subsequent tumor irradiation therapy. In another embodiment, the independent control of the tomographic imaging process and X-ray collection process allows simultaneous single and/or multi-field collection of X-ray images and tomographic images easing interpretation of multiple images. Indeed, the X-ray and tomographic images are optionally overlaid to from a hybrid X-ray/proton beam tomographic image as the patient 730 is optionally in the same position for each image. In still another embodiment, the tomogram is collected with the patient 730 in the about the same position as when the patient's tumor is treated using subsequent irradiation therapy. For some tumors, the patient being positioned in the same upright or semi-upright position allows the tumor 720 to be separated from surrounding organs or tissue of the patient 730 better than in a laying position. Positioning of the scintillation plate 710 behind the patient 730 allows the tomographic imaging to occur while the patient is in the same upright or semi-upright position. The use of common elements in the tomographic imaging and in the charged particle cancer therapy allows benefits of the cancer therapy, described supra, to optionally be used with the tomographic imaging, such as proton beam x-axis control, proton beam y-axis control, control of proton beam energy, control of proton beam intensity, timing control of beam delivery to the patient, rotation control of the patient, and control of patient translation all in a raster beam mode of proton energy delivery. The use of a single proton or cation beamline for both imaging and treatment facilitates eases patient setup, reduces alignment uncertainties, reduces beam state uncertainties, and eases quality assurance. In yet still another embodiment, initially a three-dimensional tomographic proton based reference image is collected, such as with hundreds of individual rotation images of the tumor 720 and patient 730. Subsequently, just prior to proton treatment of the cancer, just a few 2-dimensional control tomographic images of the patient are collected, such as with a stationary patient or at just a few rotation positions, such as an image straight on to the patient, with the patient rotated about 45 degrees each way, and/or the patient rotated about 90 degrees each way about the y-axis. The individual control images are compared with the 3-dimensional reference image. An adaptive proton therapy is subsequently performed where: (1) the proton cancer therapy is not used for a given position based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images and/or (2) the proton cancer therapy is modified in real time based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images. Charged Particle State Determination/Verification/Photonic Monitoring Still referring to FIG. 7, the tomography system 700 is optionally used with a charged particle beam state determination system 750, optionally used as a charged particle verification system. The charged particle state determination system 750 optionally measures, determines, and/or verifies one of more of: (1) position of the charged particle beam, (2) direction of the charged particle beam, (3) intensity of the charged particle beam, (4) energy of the charged particle beam, and (5) a history of the charged particle beam. For clarity of presentation and without loss of generality, a description of the charged particle beam state determination system 750 is described and illustrated separately in FIG. 8 and FIG. 9A; however, as described herein elements of the charged particle beam state determination system 750 are optionally and preferably integrated into the nozzle system 146 and/or the tomography system 700 of the charged particle treatment system 100. More particularly, any element of the charged particle beam state determination system 750 is integrated into the nozzle system 146, the dynamic gantry nozzle 610, and/or tomography system 700, such as a surface of the scintillation plate 710 or a surface of a scintillation detector, plate, or system. The nozzle system 146 or the dynamic gantry nozzle 610 provides an outlet of the charged particle beam from the vacuum tube initiating at the injection system 120 and passing through the synchrotron 130 and beam transport system 135. Any plate, sheet, fluorophore, or detector of the charged particle beam state determination system is optionally integrated into the nozzle system 146. For example, an exit foil of the nozzle 610 is optionally a first sheet 760 of the charged particle beam state determination system 750 and a first coating 762 is optionally coated onto the exit foil, as illustrated in FIG. 7. Similarly, optionally a surface of the scintillation plate 710 is a support surface for a fourth coating 792, as illustrated in FIG. 7. The charged particle beam state determination system 750 is further described, infra. Referring now to FIG. 7, FIG. 8, and FIG. 9A, four sheets, a first sheet 760, a second sheet 770, a third sheet 780, and a fourth sheet 790 are used to illustrated detection sheets and/or photon emitting sheets upon transmittance of a charged particle beam. Each sheet is optionally coated with a photon emitter, such as a fluorophore, such as the first sheet 760 is optionally coated with a first coating 762. Without loss of generality and for clarity of presentation, the four sheets are each illustrated as units, where the light emitting layer is not illustrated. Thus, for example, the second sheet 770 optionally refers to a support sheet, a light emitting sheet, and/or a support sheet coated by a light emitting element. The four sheets are representative of n sheets, where n is a positive integer. Referring now to FIG. 7 and FIG. 8, the charged particle beam state verification system 750 is a system that allows for monitoring of the actual charged particle beam position in real-time without destruction of the charged particle beam. The charged particle beam state verification system 750 preferably includes a first position element or first beam verification layer, which is also referred to herein as a coating, luminescent, fluorescent, phosphorescent, radiance, or viewing layer. The first position element optionally and preferably includes a coating or thin layer substantially in contact with a sheet, such as an inside surface of the nozzle foil, where the inside surface is on the synchrotron side of the nozzle foil. Less preferably, the verification layer or coating layer is substantially in contact with an outer surface of the nozzle foil, where the outer surface is on the patient treatment side of the nozzle foil. Preferably, the nozzle foil provides a substrate surface for coating by the coating layer. Optionally, a binding layer is located between the coating layer and the nozzle foil, substrate, or support sheet. Optionally, the position element is placed anywhere in the charged particle beam path. Optionally, more than one position element on more than one sheet, respectively, is used in the charged particle beam path and is used to determine a state property of the charged particle beam, as described infra. Still referring to FIG. 7 and FIG. 8, the coating, referred to as a fluorophore, yields a measurable spectroscopic response, spatially viewable by a detector or camera, as a result of transmission by the proton beam. The coating is preferably a phosphor, but is optionally any material that is viewable or imaged by a detector where the material changes spectroscopically as a result of the charged particle beam hitting or transmitting through the coating or coating layer. A detector or camera views secondary photons emitted from the coating layer and determines a position of a treatment beam 269, which is also referred to as a current position of the charged particle beam or final treatment vector of the charged particle beam, by the spectroscopic differences resulting from protons and/or charged particle beam passing through the coating layer. For example, the camera views a surface of the coating surface as the proton beam or positively charged cation beam is being scanned by the first axis control 142, vertical control, and the second axis control 144, horizontal control, beam position control elements during treatment of the tumor 720. The camera views the current position of the charged particle beam or treatment beam 269 as measured by spectroscopic response. The coating layer is preferably a phosphor or luminescent material that glows and/or emits photons for a short period of time, such as less than 5 seconds for a 50% intensity, as a result of excitation by the charged particle beam. The detector observes the temperature change and/or observe photons emitted from the charged particle beam traversed spot. Optionally, a plurality of cameras or detectors are used, where each detector views all or a portion of the coating layer. For example, two detectors are used where a first detector views a first half of the coating layer and the second detector views a second half of the coating layer. Preferably, at least a portion of the detector is mounted into the nozzle system to view the proton beam position after passing through the first axis and second axis controllers 142, 144. Preferably, the coating layer is positioned in the proton beam path 268 in a position prior to the protons striking the patient 730. Referring now to FIG. 1 and FIG. 7, the main controller 110, connected to the camera or detector output, optionally and preferably compares the final proton beam position or position of the treatment beam 269 with the planned proton beam position and/or a calibration reference to determine if the actual proton beam position or position of the treatment beam 269 is within tolerance. The charged particle beam state determination system 750 preferably is used in one or more phases, such as a calibration phase, a mapping phase, a beam position verification phase, a treatment phase, and a treatment plan modification phase. The calibration phase is used to correlate, as a function of x-, y-position of the glowing response the actual x-, y-position of the proton beam at the patient interface. During the treatment phase, the charged particle beam position is monitored and compared to the calibration and/or treatment plan to verify accurate proton delivery to the tumor 720 and/or as a charged particle beam shutoff safety indicator. Referring now to FIG. 10, the position verification system 172 and/or the treatment delivery control system 112, upon determination of a tumor shift, an unpredicted tumor distortion upon treatment, and/or a treatment anomaly optionally generates and or provides a recommended treatment change 1070. The treatment change 1070 is optionally sent out while the patient 730 is still in the treatment position, such as to a proximate physician or over the internet to a remote physician, for physician approval 1072, receipt of which allows continuation of the now modified and approved treatment plan. Referring now to FIG. 13B, a second example of the integrated cancer treatment—imaging system 1300 is illustrated using greater than three imagers. Still referring to FIG. 13B, two pairs of imaging systems are illustrated. Particularly, the first and second imaging source 1312, 1314 coupled to the first and second detectors 1322, 1324 are as described supra. For clarity of presentation and without loss of generality, the first and second imaging systems are referred to as a first X-ray imaging system and a second X-ray imaging system. The second pair of imaging systems uses a third imaging source 1316 coupled to a third detector 1326 and a fourth imaging source 1318 coupled to a fourth detector 1328 in a manner similar to the first and second imaging systems described in the previous example. Here, the second pair of imaging systems optionally and preferably uses a second imaging technology, such as fluoroscopy. Optionally, the second pair of imaging systems is a single unit, such as the third imaging source 1318 couple to the third detector 1328, and not a pair of units. Optionally, one or more of the set of imaging sources 1310 are statically positioned while one of more of the set of imaging sources 1310 co-rotate with the gantry 960. Pairs of imaging sources/detector optionally have common and distinct distances, such as a first distance, d1, such as for a first source-detector pair and a second distance, d2, such as for a second source-detector or second source-detector pair. As illustrated, the tomography detector or the scintillation plate 710 is at a third distance, d3. The distinct differences allow the source-detector elements to rotate on a separate rotation system at a rate different from rotation of the gantry 960, which allows collection of a full three-dimensional image while tumor treatment is proceeding with the positively charged particles. For clarity of presentation, referring now to FIG. 13C, any of the beams or beam paths described herein is optionally a cone beam 1390 as illustrated. The patient support 152 is an mechanical and/or electromechanical device used to position, rotate, and/or constrain any portion of the tumor 720 and/or the patient 730 relative to any axis. Still yet another embodiment includes any combination and/or permutation of any of the elements described herein. Herein, any number, such as 1, 2, 3, 4, 5, is optionally more than the number, less than the number, or within 1, 2, 5, 10, 20, or 50 percent of the number. The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. In the foregoing description, the invention has been described with reference to specific exemplary embodiments; however, it will be appreciated that various modifications and changes may be made without departing from the scope of the present invention as set forth herein. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the generic embodiments described herein and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present invention and are accordingly not limited to the specific configuration recited in the specific examples. Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below. In a fourth example, the gantry comprises at least two imaging devices, where each imaging device moves with rotation of the gantry and where the two imaging devices view the patient 730 along two axes forming an angle of ninety degrees, in the range of eighty-five to ninety-five degrees, and/or in the range of seventy-five to one hundred five degrees. Pendant Referring still to FIG. 12A and referring now to FIG. 12B, a pendant system 1250, such as a system using the external pendant 1216 and/or internal pendent 1218 is described. In a first case, the external pendant 1216 and internal pendant 1218 have identical controls. In a second case, controls and/or functions of the external pendant 1216 intersect with controls and/or function of the internal pendant 1218. Particular processes and functions of the internal pendant 1218 are provided below, without loss of generality, to facilitate description of the external and internal pendants 1216, 1218. The internal pendant 1218 optionally comprises any number of input buttons, screens, tabs, switches, or the like. The pendant system 1250 is further described, infra. |
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abstract | A beam line before incidence on a beam scanner is arranged with an injector flag Faraday cup that detects a beam current by measuring a total beam amount of an ion beam to be able to be brought in and out thereto and therefrom. When the ion beam is shut off by placing the injector flag Faraday cup on a beam trajectory line, the ion beam impinges on graphite provided at the injector flag Faraday cup. At this occasion, even when the graphite is sputtered by the ion beam, since the injector flag Faraday cup is arranged on an upstream side of the beam scanner and the ion beam is shut off by the injector flag Faraday cup, particles of the sputtered graphite do not adhere to a peripheral member of the injector flag Faraday cup. |
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052746828 | summary | FIELD OF THE INVENTION The present invention relates to the consolidation of spent nuclear fuel rods, and, more particularly, to a storage canister for spent rods and the method of loading and sealing it. BACKGROUND OF THE INVENTION Nuclear fuel assemblies for powering nuclear reactors generally consist of large numbers of fuel rods contained in discrete fuel rod assemblies. These assemblies or cells generally consist of a bottom end fitting or nozzle, a plurality of fuel rods extending upwardly therefrom and spaced from each other in a square or triangular pitch configuration, spacer grids situated periodically along the length of the assembly for support and orientation of the fuel rods, a plurality of control guide tubes interspersed throughout the rod assembly, and a top end fitting or cap. Moreover, the assembly is installed and removed from the reactor as a unit. When the nuclear fuel rods have expended a large amount of their available energy, the fuel rods are considered to be "spent," and the fuel rod assembly is pulled from the reactor and temporarily stored in an adjacent pool until the assemblies are transported to a reprocessing center or to permanent or temporary storage. Even though the rods are considered "spent," they are still highly radioactive and constitute a very real hazard both to personnel and to property. In general, there are a number of alternatives available for disposition of the radioactive spent fuel rods, none of which is totally satisfactory. The fuel rod assemblies can be enclosed in a suitable basket and cask arrangement and transported to a storage facility, or possibly, to a reprocessing plant. A second alternative is to store the spent fuel in a dry storage system. Dry storage entails either the use of a large number of metal casks or the building of massive concrete containers either above or below ground, which is a very expensive process, and, where the storage system is above ground, it is often not acceptable to people living or working in its vicinity. A third alternative is the storage of the fuel units in the existing water pool originally designed for temporary storage. This type of storage is the simplest and cheapest, since the fuel rod assemblies can remain in the pool and be left there until the appropriate governmental agency or other agency collects them, often at the end of the life of the nuclear plant. However, such storage pools have a limited capacity, and, where they are adjacent to the nuclear reactor, when one becomes full the construction of a new pool is necessary. Numerous attempts have been made to increase the capacity of a pool through a process known as fuel rod compaction or consolidation. This process, in brief, comprises removing the fuel rods from each fuel rod assembly and placing them in a storage canister where they are placed in rows with minimal spacing, most often in a square or triangular array. It is possible, with this process, to place the fuel rods from two or more fuel assemblies into a single storage canister, thereby achieving approximately a 1:2 reduction in required pool volume, or, conversely, a 2:1 increase in pool storage capacity. Examples of such rod consolidation systems are shown in U.S. Pat. No. 4,659,536 of Baudro; U.S. Pat. No. 4,731,219 of Beneck, et al.; and U.S. Pat. No. 5,000,906 of Ellingson, et al. However, successful consolidation has been an elusive goal for a number of reasons. Inasmuch as the pools are approximately forty feet deep, and inasmuch as the rods must remain immersed in the water at all times, all of the consolidation operations must be performed under the shielding and cooling water. In addition, even though the rods are kept under water, the process could be quite hazardous to personnel performing the operation. The rods themselves, because of their dimensions, for example, one-half inch in diameter and eighteen feet long, are subject to flexing and bending. As a consequence, placing the rods in a desired location can be quite difficult. Prior art arrangements, such as the Beneck et al. system, for achieving rod consolidation have included a system whereby the rods are pulled out row-by-row, as in, for example, a 14.times.14 matrix of rods, lifted and deposited in a tapered interim storage container, which tapers from a large area top opening to a bottom that has the area of a storage canister. After the intermediate container has the rods from approximately two fuel assemblies deposited therein, the intermediate container is placed over a storage canister, and the bottom plate of the tapered container is lowered or removed to cause the rods to slide into the storage canister. If the rods jam or stick, as they often do, they must be pushed from above the pool by operators using long rods. This last operation is made more difficult in that the rods develop on their outside surfaces what is referred to in the trade as "crud". When the fuel rods are pulled, this radioactive crud is scraped off and clouds the water making it difficult for the operators to see what they are doing and contaminating the pool. The method just described has proven to be quite slow and complicated, and can be hazardous to personnel. After a storage canister has been filled, it is generally capped by a lid member. In accordance with U.S. government requirements for storing spent nuclear fuel rods, the lid must be lockable or self-locking with tamper proof, or tamper indicating mechanisms. Meticulous records must be kept by the operator as to just what has been put in the canister and when, and the lock and tamper indicator is intended to insure that what has been put in the canister remains there, undisturbed. An example of a storage canister and a lid locking mechanism is disclosed in U.S. Pat. No. 4,474,727 of Kmonk, et al. SUMMARY OF INVENTION The present invention is a storage canister for spent nuclear fuel rods and the method of loading and locking the canister with a tamper indicating mechanism. The apparatus and methodology of the present invention may, for example, be primarily used in an automated nuclear fuel rod consolidation system which comprises a commercially available five or six axes robot mounted on the operations floor along the side of the storage pool. Directly below the robot within the pool, at a depth of, for example, twenty-five feet, is an apertured work table, and resting on the floor of the pool directly below the work table is a header and support base, which includes a manifold for a pair of vacuum filter assemblies which are mounted to, and extend upwardly from, the support base. Extending vertically from the support base and into openings in the work table are a plurality of holders configured to support fuel assemblies or fuel rod canisters, which are accessible from above the work table. A plurality of individual or multiple purpose long reach tools are mounted on racks above and to either side of the work table. Each of the tools has a quick change coupling mounted to its upper end which matches and is adapted to couple with a corresponding quick change coupling on the end of the robot arm. Locating pins are mounted on the top surface of the work table, and a position sensor carried by one of the long reach tools sends signals to the computer to give precise locations on the work table, thereby enabling the computer to determine the exact location of all components in the system. In operation, three or four spent fuel rod assemblies are transferred, under water, to the fuel rod assembly holders as dictated by the number of cells provided in the work table for fuel rod assemblies. Empty canisters are transferred to canister holders and their lids are placed in a well located in the work table. The upper end fittings of the fuel rod assemblies are then cut away by a long reach tool having a cutter on its lower end and placed in a scrap canister. Alternatively, the upper end fittings can be unbolted on those fuel assembly types which permit this type of removal. The computer next directs the robot to couple with a fuel rod transfer tool having a collet for grasping a fuel rod and pulling it out of the rod assembly up into the tool. When this occurs, crud is scraped off of the rod, but, because of the downward water current created by the filter units with their associated pumps, the crud passed down the holder into the manifold and up through the filter, thereby preventing clouding of the water and contamination of the pool. To ensure that the rod transfer tool centers exactly over a rod to be pulled, an apertured funnel guide plate is placed over the fuel rod assembly, which precisely locates every fourth rod in the assembly, for example. The funnel guide plate is indexed by means of locating pins that fit into holes in the work table or by slots or channels on the underside of the plate that engages the top edges of the canister so that ultimately all of the rods are pulled. The funnel guide plate is the subject of U.S. patent application Ser. No. 07/831,404, filed Feb. 5, 1992, of which this application is a continuation-in-part. After the canister is completely filled, the skeleton of the fuel rod assembly, comprising guide tubes and spacer grids, is subjected to compaction. The guide tubes are cut above and below the grids, and each tube section is fed into the tube compactor where it is repeatedly cut and flattened into small pieces and then dropped into the scrap canister. Finally, the spacer grids are introduced into a grid crushing apparatus, where the spacer grids are crushed in accordance with a novel methodology which forms the basis of U.S. patent application Ser. No. 07/570,812, filed Aug. 22, 1990, also a continuation in part of U.S. patent application Ser. No. 07/831,404 filed Feb. 5, 1992. In accordance with the present invention, in a preferred embodiment thereof, the storage canister has a loading configuration and a storage configuration and comprises an elongated hollow tubular member, rectangular or square shaped in cross-section, having a plurality of spacers or dividers therein and affixed thereto, defining an array of rod locations within the canister. The bottom wall of the canister has an opening therein for permitting passage of water therethrough, and an apertured base plate, axially slidably located in the bottom of the canister, is adapted to permit ingress and egress of water through the bottom wall in a first, or loading configuration position, and to block, confine, or restrict passage of water in a second, or storage configuration position. Mounted on the top surface of the base plate and spaced therefrom is a plurality of horizontal apertured plates, spaced from each other. The apertures in the plates are aligned and oriented with respect to each other so that some fuel rods extend through the array with their tips resting on the base plate; some fuel rods pass through the array to where their tips rest upon the first plate of the array which is adjacent to the base plate; some fuel rods pass through the array to where their tips rest upon the second plate in the array, and some rods have their tips resting upon the top plate of the array. As a consequence, adjacent rods are vertically displaced from each other so that the rod grasping tool can grasp a rod without interference from adjacent rods, the highest rods in the array being the last to be inserted. The storage canister has mounted therein a plurality of corrugated plate members or spacers which extend along a portion of the interior length of the canister. Adjacent pairs of the plates define a plurality of longitudinally extending rod locating passages so that when a rod is inserted into a passageway, it maintains a fixed transverse location as it passes down the length of the canister until the tip passes into the array of apertured plates. Thus, the pairs of corrugated plate members define a plurality of rod locations within the canister. The apertures in the plates of the array are oriented so that no two adjacent rods rest upon the same plate, thus adjacent rods are vertically staggered with respect to each other. Each fuel rod is characterized by a weld bead where the rod tip is welded to the rod, both at the top and bottom thereof. The staggered arrangement of the rods permits the rods to be placed in close proximity to each other without the weld beads of adjacent rods interfering with each other, whether during insertion or as finally positioned within the canister. As discussed heretofore, the exterior of the rod is characterized by a deposit of "crud" which, during insertion of the rod into the storage canister, is scraped off as it passes down between the corrugated plates. In order to facilitate removal of the "crud", a central opening or plurality of openings in the bottom wall of the canister communicates with the vacuum pump assembly through the base of the holder so that a current flows downward through the bottom of the holder. A significantly small volume of the surrounding pool water is also drawn in by the vacuum pump. This adjacent water flows upward through the central screened aperture of the base of the canister, and back out of the canister base through additional apertures encircling the central screened aperture in the base, thereby preventing a buildup of crud on the screen which must allow free upward flow later when in the storage configuration. To facilitate a large volume downward flow during the fuel rod loading configuration, the apertured base plate of the array of plates, and the array itself are lifted up from the bottom of the holder by pins or other means in the loading configuration, and, when the canister is full and is lifted out of the holder, the bottom wall of the canister moves up into contact with the base plate so that the apertured base plate rests against the bottom wall, thereby sealing off all the apertures in the wall except the central screen aperture while in the storage configuration. The storage canister of the invention is provided with two slots on each side adjacent the top edge. A closure or cap member has eight locking cams oriented to fit within the slots, and threaded bolt members for rotating the cams to force them into the slots when the closure member is in position within the top end of the canister. Each bolt member has fitted thereon a circular tamper indicator having a detent recess on its underside. Within the top plate of the closure member are spring loaded plungers adapted to fit within the detent recesses of the tamper indicators, and thus, as the bolts are screwed down to force the cams into the slots, the tamper indicator descends until the detent recesses are engaged by the corresponding plungers. The position of the indicators on the bolts in such that the detent is engaged at that point where the cams are firmly seated in the slots, thus locking the closure lid in place. Any further rotation of the bolts, in either direction, will cause permanent distortion of the indicator members inasmuch as the plungers in the detents prevent rotation of the indicator members. Thus, any attempt to unlock the closure after it is properly locked in place will result in a distorted indicator, thereby indicating tampering. The various features and advantages of the present invention will be more readily seen from the following detailed description, read in conjunction with the accompanying drawings. |
044937920 | abstract | Method and apparatus for minimizing diversion of radioactive samples from a nuclear fuel sampling system. The apparatus includes a sampler for drawing a radioactive sample from a remote vessel containing nuclear fuel. The sampler is located within a shielding enclosure that has solid walls for preventing direct physical access to the sampler. A tray is located in the wall of the enclosure and is used for translating a sample vessel in and out of the enclosure. The apparatus further includes a time lock escapement that periodically immobilizes the tray for a period of time sufficient to minimize diversion of the radioactive samples. |
claims | 1. A detection system comprising:a substrate having a detection surface for holding a sample and including an excitation region at least partly in contact with the sample, and a radiation coupling arrangement for advancing excitation radiation from an excitation radiation source to the citation region to interact with bound labels of the sample to produce light coming from the bound labels;a collection arrangement positioned in the excitation region for collecting and directing the light coming from the bound labels;a detector for detecting the collected light; anda magnet arrangement configured to be disposed next to and at the same side of the detection surface, to be stationary with respect to the excitation radiation source and the radiation coupling arrangement, and to attract magnetic beads within the sample to the detection surface. 2. The detector system as claimed in claim 1, wherein the excitation radiation is evanescent. 3. The detection system as claimed in claim 1, further comprising a magnetic field guide arrangement for focusing the magnetic field from the magnet arrangement to the excitation region. 4. The detection sterna claimed in claim 3, wherein the magnetic field guide arrangement comprises an opening through which the radiation coupling arrangement guides the excitation radiation and/or the light coming from the bound labels. 5. The detection system as claimed in claim 4, wherein the radiation coupling arrangement is configured to advance the excitation radiation to the excitation region up a center of the field guide arrangement. 6. The detection system as claimed in claim 5, further comprising a beam splitter for providing different radiation paths for the light coming from the bound labels and the excitation radiation. 7. The detection system as claimed in claim 1, wherein the detector is mounted on the surface of the magnet arrangement that is closest to the sample holder. 8. The detection system as claimed in claim 1, further comprising a carrier movable between a magnetic actuation position and a detection position,wherein the detector and the magnet arrangement are mounted side by side on the carrier. 9. The detection system as claimed in claim 1, wherein the detector comprises a radiation focusing arrangement. 10. The detection system as claimed in claim 1, wherein the detector comprises one of a radiation band pass and high pass filter. 11. The detection system as claimed in claim 1, wherein the radiation coupling arrangement comprises a radiation arrangement associated with the excitation radiation source for directing the excitation radiation to the excitation region at an acute angle with respect to the detection surface of the substrate, such that the substrate provides total internal reflection. 12. The detection system as claimed in claim 1, wherein the radiation coupling arrangement comprises an evanescent radiation guide. 13. The detection system as claimed in claim 1, wherein the excitation radiation is light and the collected light is luminescence radiation. 14. The detection system as claimed in claim 1, wherein the detector comprises a pixelated light detector. 15. The detection system as claim in claim 1, wherein the excitation radiation source a light emitting diode (LED) and the collected light is scattered light. 16. A detection method comprising acts of:disposing a magnet arrangement next to and at the same side of a detection surface of a substrate, the detection surface holding a sample and including an excitation region at least partly in contact with the sample;advancing excitation radiation from an excitation radiation source to the excitation region using a radiation coupling arrangement to interact with bound labels of the sample producing light coming from the bound labels;collecting and directing radiation of the light coming from the bound labels using a collection arrangement positioned in the excitation region; anddetecting the collected light coming from the bound labels. 17. The method as claimed in claim 16, comprising an act of mounting the detector on the surface of the magnet arrangement that is closest to the sample holder. 18. The method as claimed in claim 16, comprising acts of:providing a carrier movable between a magnetic actuation position and a detection position; andmounting the detector end the magnet arrangement side by side on the carrier. 19. A detection system comprising:a substrate having a detection surface for holding a sample and including an excitation region in contact with the sample, and a radiation coupling configured to advance excitation radiation from an excitation radiation source to the excitation region to interact with bound labels of the sample to produce light coming from the bound labels;a collector positioned in the excitation region configured to collect and direct the light coming from the bound labels;a magnet arrangement configured to be disposed next to and at the same side of the detection surface, to be stationary with respect to the excitation radiation source and the radiation coupling arrangement, and to attract magnetic beads within the sample to the detection surface; anda detector, configured to detect the light coming from the bound labels, mounted on the surface of the magnet arrangement that is closest to the sample holder. 20. The detection system as claimed in claim 19, further comprising a carrier movable between a magnetic actuation position and a detection position,wherein the detector and the magnet arrangement are mounted side by side on the carrier. |
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description | This patent application is related to co-pending, commonly-owned U.S. patent application Ser. No. 11/564,183 entitled “Prognostic Condition Assessment Decision Aid”, filed under US concurrently herewith on Nov. 28, 2006, and to commonly-owned U.S. patent application Ser. No. 10/770,672 entitled “Lifecycle Support Software Tool,” filed on Feb. 2, 2004, now U.S. Pat. No. 7,206,708 which applications are hereby incorporated by reference. The present invention relates to operational analysis of vehicles, and more specifically, to methods and systems for health operations analysis models to compare a first and second fleet of vehicles. The operation and maintenance of a fleet of military, commercial, or private vehicles can be economically burdensome for an organization. Many costs are realized over a period of time when an organization maintains a fleet of military, commercial, or private vehicles. Initial considerations are often limited to the cost of the vehicles, related design and development costs, and maintenance costs as the major considerations in acquiring or upgrading a fleet of vehicles. However, a number of considerations are often under-analyzed or completely ignored because they are not well understood by an organization. For example, reliability, maintainability, and testability are often not factors considered when determining the cost of a fleet of vehicles, although support requirements and health management are significant operational drivers for a fleet of vehicles. The integration of health management into the initial design of a vehicle may include a detailed benefit analysis, including all of the operational performance benefits that an integrated health management system may provide. Such a detailed benefit analysis may include the observations and recommendations of original equipment manufacturers (OEMs), mission operators, command and control elements, fleet management, and maintenance operations. Therefore, it would be advantageous to provide a system health operations analysis model providing performance improvement on a fleet of vehicles without disproportionately increasing operational costs, and while reducing the total ownership cost over the service life of the fleet of vehicles. The present invention relates to methods and systems for health operations analysis models to compare a first and second fleet of vehicles. In one embodiment, a method includes providing a system health operations analysis model, comprising determining a first system health operations analysis of a first fleet of vehicles, determining a second system health operations analysis of a second fleet of vehicles, comparing the first and second system health operations analyses, and generating a system health operations output of the first and second system health operations analyses. In another embodiment of the present invention, a computer-based system includes providing a system health operations analysis comprising an analysis component configured to compute a system health operations analysis of a first fleet of vehicles and a system health operations analysis of a second fleet of vehicles, a comparator configured to receive the system health operations analyses from the analysis component and to perform a comparison between the first and second system health operations analyses, and an output component configured to receive the comparison from the comparator and to provide a visual display of the comparison between the first and second system health operations analyses. In yet another embodiment of the present invention, one or more computer-readable media comprise computer executable instructions that, when executed, perform a method of health operations analysis, comprising determining a system health operations analysis of a first fleet of vehicles to determine the operational costs of the first fleet of vehicles, determining a system health operations analysis of a second fleet of vehicles to determine the operational costs of the second fleet of vehicles, and wherein determining the system health operations analysis of at least one of the first and second fleets includes determining the system health operations analysis based on at least one of an actual operational data, an actual maintenance data, a hypothetical operational data, and a hypothetical maintenance data, comparing the first and second system health operations analyses and operational costs, and generating a system health operations output of the compared first and second system health operations analyses including at least one of cost metrics and reliability metrics. The present invention relates to methods and systems for health operations analysis models. Many specific details of certain embodiments of the invention are set forth in the following description and in FIGS. 1 through 11 to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description. FIG. 1 illustrates an overall environment 100 for operating health operations analysis models in accordance with an embodiment of the present invention. As shown in FIG. 1, a user 102 interacts with a computing device 110 in network connection 120 with a server 140. The computing device 110 may be a desktop, mobile, handheld, or laptop computer, or any other suitable computer-based device. The computing device 110 may include a number of components 112. The components 112 may include one or more processors 114 that are coupled to instances of a user interface (UI) 116. The user interface 116 represents any devices and related drivers that enable the computing device 110 to receive input from the user 102, and to provide output to the user 102. Thus, to receive input from the user 102, the user interface 116 may include keyboards or keypads, mouse devices, touch screens, microphones, speech recognition packages, or the like. To provide output to the user 102, the user interface 116 may include speakers, display screens, printing mechanisms, or the like. The computing device 110 may include one or more instances of a computer-readable storage medium 118 that are addressable by the processor 114. As such, the processor may read data or executable instructions from, or store data to, the storage medium 118. The storage medium 118 may contain a client-based discrete even simulation component 119, which may be implemented as one or more software modules that, when loaded into the processor 114 and executed, cause the computing device 110 to perform any of the functions described herein. Additionally, the storage medium 118 may contain implementations of any of the various software modules described herein. Similarly, the server 140 may include a number of components 142. The server may include one or more processors 144 that are coupled to instances of a user interface (UI) 146. The user interface 146 represents any devices and related drivers that enable the server 140 to receive input from the user 102, and to provide output to the user 102. The server 140 may include one or more instances of a computer-readable storage medium 148 that are addressable by the processor 144. As such, the processor may read data or executable instructions from, or store data to, the storage medium 148. The storage medium 148 may contain a server-based discrete even simulation component 149, which may be implemented as one or more software modules that, when loaded into the processor 144 and executed, cause the server 140 to perform any of the functions described herein. Additionally, the storage medium 148 may contain implementations of any of the various software modules described herein. Having presented the above overview of the environment 100, the discussion now turns to a description of further details of the overall environment, now presented with FIG. 2. FIG. 2 is a flow diagram 200 of a model for creating a system health operations analysis in accordance with an embodiment of the invention. Input data 210 is generated from a plurality of sources, each of which may include processes and metrics. In this embodiment, the sources include production processes and metrics 212, mission processes and metrics 214, maintenance processes and metrics 216, command and control processes and metrics 218, and fleet management processes and metrics 220. In alternate embodiments, other data sources may be used. Each of these sources, including the processes and metrics, may contain actual data from a fleet of vehicles. A fleet of vehicles is a plurality of vehicles. Alternatively, predicted or modeled data (together referred to as “hypothetical data”) may be incorporated into some or all of the sources along with actual data, thus supplying the input data 210 with at least some hypothetical data. For example, when data does not exist for a particular source, such as mission processes and metrics 214, it may be desirable to input hypothetical data into this source to facilitate running of the analysis. In some embodiments, the sources may only contain actual data from a fleet of vehicles. In other embodiments, a source may contain only hypothetical data such as a source for a vehicle that is not currently in operation, but only exists in a conceptual stage of development. Each data input 210 may include tasks and specific measures of effectiveness, or objectives. For example, the production processes and metrics 212 may include design, integration and production of the vehicles which meet the organization's contractual requirements, and further may focus on reducing costs for the original equipment manufacturers (OEMs). The mission processes and metrics 214 may include tasks such as performing missions, operating vehicles, and generating maintenance needs, and further may focus on mission reliability and mission effectiveness. The maintenance processes and metrics 216 may include tasks such as performing scheduled and unscheduled maintenance, and further may focus on maintenance man hours, awaiting maintenance time, inventory costs, and turnaround time. The command and control processes and metrics 218 may include tasks such as risk management and mission planning, and further may focus on effective mission generation, logistics, and scenario closure. Fleet management processes and metrics 220 may include tasks such as matching vehicles to mission requirements, maintenance planning, managing fleet health and planning deployments, and further may focus on managing costs, manpower, operational availability, and spare vehicles. Additionally, other input data sources may have their own specific measures of effectiveness related to operational goals. The input data 210 is entered into a computing device 240, such as the computing device 110 or server 140 represented in FIG. 1, which processes the input data 210. The computing device 240 includes components 242 such as a processor 244, user interface 246, and storage medium 248. Additionally, the components 242 include a discrete event simulation component 249 in order to compute a system health operation analysis in accordance with an embodiment of the present invention. As further shown in FIG. 2, the computing device 240 populates an output database 290 by processing the input data 210 using the discrete event simulation component 249. The output database 290 may then be used by a system health operation analysis model to compare the system health operations analysis of a first fleet of vehicles to the system health operations analysis of a second fleet of vehicles, or to some other standard for comparison, such as a theoretical standard, a target or projected standard, or any other suitable analysis result. FIG. 3 illustrates a flow diagram of a model 300 for creating a system health operations analysis in accordance with another embodiment of the invention. At block 310, data is gathered to populate the model. With reference to FIG. 2, this data may include data from one or more of the sources 212, 214, 216, 218, and 220, although additional sources may be utilized. Further, the data may be actual data, hypothetical data, or a combination of actual and hypothetical data. If a vehicle of a fleet under analysis is in current operational condition or existence, then inputs will usually be queried from the appropriate vehicle maintenance information system. The level of detail of the inputs may vary in some embodiments, depending on the amount of detail that is available for a fleet of vehicles. Further, in various alternate embodiments, the input data may represent varying periods of time, such as a one year history, or greater or lesser periods of time. At block 320, system sensitivities to logistics resources and new operational concepts are developed. In some embodiments, the system sensitivity analysis may be the analysis of performance changes made possible by varying specific input parameters. For example, reducing fault isolation time on an avionics system input may increase the operational availability of a fleet or decrease manpower requirements (and therefore costs) of an organization. The magnitude of the system performance change, given equal increments of input change, will not typically be linear. Therefore, there is a “sensitive” input range that may be identified to develop solutions with a cost benefit that fits within cost constraints and program objectives. Further, system sensitivities may be input in the form of utilization rates, which act as effectiveness factors, and may vary the productivity or computation of an input data set. At block 330, health management solution assumptions are developed. Various embodiments of analysis models may have a number of assumptions that must be made to support the analysis. Some of these assumptions may be relatively obvious from the information available from an existing fleet. Others may be less obvious, particularly if the vehicle under analysis is still in the conceptual phase. Some of the health management solution assumptions may overlap with input data in the case of a development program. For example, gate turn time may be available from a maintenance information system on a current platform. It may also be an important factor that must be verified before conducting analysis on the model. In some embodiments, the health management solution assumptions developed at block 330 may include: development period, aircraft production schedule, fleet size, aircraft service life, aircraft utilization, average flight duration (hours), maintainer labor rates, maintenance resources and schedules, average gate turn time, operational tempo changes (flight schedule changes), and mission types, priorities, and other features. Additionally, a health management solution may also include the following assumptions: event horizon, prognostic coverage, ability to fault forwarding (e.g., providing an RF link to maintenance services), and fault ambiguity of the forwarded message. At block 340, a benefit analysis is developed. In some embodiments, the benefit analysis feeds into a comprehensive business case, and may include factors such as engineering cost estimates which illustrate a second fleet cost versus a benefit of a second fleet's solution (e.g., cost to install a new apparatus versus benefit realized thorough implementation of a new system or apparatus). For example, the benefit analysis may be developed to account for a number of maintenance man hours used, incorporating different rates of pay for each type of maintenance position, and including the times when those positions are utilized. At block 350, a system health operations analysis is created for a fleet of vehicles. In one embodiment of environment 300, the system health operations analysis model will incorporate data from each of the proceeding blocks (310, 320, 330, 340). FIG. 4 is a schematic view of a model 400 for comparing two system health operations analyses in accordance with another embodiment of the invention. The comparison may include a first fleet of vehicles 410 and a second fleet 420 of vehicles. The vehicles may be airplanes, automobiles, trucks, maritime vessels, weapons, missiles, unmanned aerial vehicles, machinery and equipment used in above-ground or underground mining, buses, trains, railroad equipment, and other types of manned or unmanned mobile platforms. The vehicles may be used for military, commercial, or private use. For example, commercial aircraft (as shown in FIG. 4) and military aircraft may provide large fleets of vehicles while managing large operational budgets. Additionally, the vehicles may include drivers, pilots, captains, or other human operators, or they may be computer controlled from a remote location, such as a drone aircraft controlled by a computer and remote operator or autonomously guided. The first and second fleet of vehicles 410, 420 may be a group of similar vehicles, such that they are all of the some model and production year, or they may have substantial variance in configuration. More specifically, in some embodiments, the vehicles in the first fleet 410 may be substantially the same vehicles as the vehicles in the second fleet 420, while in other embodiments, some aspects of the first and second fleet of vehicles are different. For example, in a particular embodiment, the first fleet 410 may be a fleet of Boeing 737 commercial airplanes in an existing operational configuration while the second fleet 420 may be a fleet of Boeing 737 commercial airplanes with a new (or proposed) operational configuration. Alternatively, the vehicles in the first fleet 410 may be different vehicles than those in the second fleet 420 of vehicles. For example, in another particular embodiment, the first fleet 410 of vehicles may include a fleet of Boeing 737 commercial airliners while the second fleet of vehicles 420 may include a fleet of Boeing 787 commercial airliners. In the above example, it is contemplated that an organization may want to determine if it would be cost effective to convert a fleet of 737 airplanes to a fleet of 787 airplanes. While this example may assume both the first fleet of vehicles 410 and second fleet of vehicles 420 are in current operational status, this may not necessarily be true. If the 787 airplanes in the above example are under development, they may entail proposed or hypothetical data inputs into a system health operations analysis. Once the configuration of the first and second fleet of vehicles 410, 420 is determined, the system health operations analysis of the first and second fleet 412, 422 may be determined. The system health operations analysis of the first and second fleet 412, 422 are then compared 430 in order to create an output database 440. The output database 440 may contain data and information concerning the system health operations analyses of the first and second fleets 412, 422, and other relevant data such as cost analysis, life cycle analysis, input assumptions, and the like. The output database 440 enables a researcher or analyst to extract data in order to make a determination upon whether the second fleet has an optimal health management system resulting in metrics linked to operational goals. For example, a researcher or analysis might want to determine a point in future where the initial investment in upgrades to the second fleet of vehicles 420 are realized by cost savings from a proposed implementation of a system or apparatus on the second fleet of vehicles 420 that is not configured on the first fleet of vehicles 410. Other outputs to database 440 may include accumulation of fleet utilization hours, completed versus aborted missions, and the accumulation of flight time. In FIG. 5, a schematic view of another model 500 for comparing two system health operations analyses is presented. Various data inputs are compiled for a first and second fleet of vehicles 410, 420 (FIG. 4,) such as mission requirements 510, maintenance requirements 520, prognostic health indicators 530, maintenance schedule and concepts 540, and fleet resource availability 550. The mission requirements 510 include information relating to the number of flights, missions, or trips of a fleet. For example, in the situation where a fleet is a group of carrier vans, the number of trips for the first fleet may be set to one hundred (100) for a day. More specific information relating to each trip may also be included in the mission requirements 510 such as the mission priority, mission duration, mission requirements, and other ongoing missions. Further, the mission difficulty, climate conditions, time between missions, rate of travel, and other information relating to the flight, mission, or trip may be included in the mission requirements 510. The maintenance requirements 520 include information relating to maintenance activities for each fleet of vehicles. Maintenance requirements may include scheduled maintenance such as routine fluid monitoring and fluid replacement of a vehicle. Additionally, maintenance requirements may include scheduled inspections. Maintenance requirements may also evaluate maintenance utilization, maintenance resources, availability of spare parts, downtime, and other metrics that involve costs to maintain a fleet of vehicles. Costs and metrics associated with man hours and inventory may be significant factors in the maintenance requirements 520, and may include time to complete maintenance on subsystems and order parts to replace inventory. As further shown in FIG. 5, the system health operations analyses may also include prognostic health indicators 530. For example, prognostic health indicators 530 may include unscheduled maintenance that may be anticipated (predicted with a certain accuracy) and statistically modeled through a time element referred to as “event horizon”, and may be an important component of maintenance, but may not exist under the traditional maintenance requirements 520. Historical and statistical information may be used to model failure rates of a fleet of vehicles which require unscheduled maintenance. Predictive maintenance capability (e.g., prognostic health indicators) may be inserted as an event horizon. This may be translated into an engineering design requirement once the appropriate event horizon is identified through use of the system health operations analysis model. Maintenance schedules and concepts 540 is yet another element that may be included in a comparison of the system health operations analyses. Maintenance schedules and concepts 540 may include fault forwarding. Fault forwarding involves communicating a maintenance request to a maintenance scheduler before the vehicle is actually available for maintenance. For example, if a sensor on an airplane detects a part failure, that “fault” may be forwarded to the maintenance scheduler who can coordinate manpower, equipment, and other maintenance needs in order to efficiently maintain or repair the airplane upon its arrival at the maintenance location. Fleet resource availability 550 is yet another element that may be included in a comparison of the system health operations analyses. Fleet resource availability may include vehicle schedules, maintainer schedules, spare vehicle acquisitions, resource planning, and other related activities for a fleet of vehicles. One fleet resource availability issue involves a decision whether to fix a vehicle or to continue operation of the vehicle (hereinafter “fix or fly decision”), which controls when maintenance is conducted. The fix or fly decision is an application of risk tolerance which may impact whether a flight, mission, or trip occurs or instead, whether maintenance must be performed. The event horizon is the predictive capability of the system to determine the amount of time before the next unscheduled maintenance. Conditioned based maintenance may be included within fleet source availability 550. Condition based maintenance may utilize one or both of event horizon and fix or fly decisions, such as if a vehicle may continue in service or should be scheduled for maintenance. Additionally, condition based maintenance may remove scheduled maintenance requirements on components (e.g., routine inspections) and insert the capability to evaluate the condition of components at any point in time to facilitate replacing components at the optimum point in time. For example, if a failure is predicted, but it is not a catastrophic failure, a conditioned based maintenance system may decide to conduct maintenance at the most cost effective time, even if that means jeopardizing the occurrence of a failure before maintenance is performed. In catastrophic failure scenarios, condition based maintenance may be used on a more conservative level, or other appropriate precautions may be implemented. At process 560, experimentation with operational scenarios and health management technologies may be performed on the various elements described above including mission requirements 510, maintenance requirements 520, prognostic health indicators 530, maintenance schedule and concepts, 540, and fleet resource availability 550 in order to evaluate the system health operations analysis of a first and second fleet of vehicles. The experimentation with operational scenarios and health management technologies 560 may permit the derivation of optimum health management solutions 570. The optimum health management solutions 570 may be related to operational costs, reliability, and operational effectiveness. Additionally, fleet metrics may be targeted for other organizational improvements such as those depicted in FIG. 2, elements 212, 214, 216, 218, 220, and for the different processes and metrics associated with a fleet of vehicles. For example, a researcher may desire to derive the optimum health management solution for a second fleet of vehicles by targeting maintenance requirements such as utilization of maintenance workers in order to reduce maintenance costs, and in turn overall fleet operational costs. Therefore, the researcher may run different scenarios of the environment 500 in order to create an optimum health management solution for a second fleet by manipulating the maintenance requirements 520. Further, it is contemplated that any of the other elements, or combination thereof, may be manipulated in order to derive the optimum health management solution 570 for a second fleet of vehicles. When comparing a first and second fleet of vehicles, some informational data inputs may be substantially the same while others may vary to a considerable degree. For example, the mission duration and mission requirements of a first and second fleet may be substantially similar while the mission priority is substantially different for the second fleet of vehicles. The analysis by a researcher may focus on cost, reliability, or other targeted improvements for a second fleet of vehicles. In FIG. 6, an embodiment of a model 600 for comparing the system health operations analysis of a first and second fleet of vehicles is depicted. The model 600 may include various data inputs and display elements (610, 620, 630, 640, 650), as described more fully below. Data may be inputted on the computer user interface, while additional data may be input from other sources such as databases or spreadsheets (e.g., Microsoft Excel). The model 600 may be used to view an animation of a system health operations analysis model as it performs a simulation of two or more fleets of vehicles, or it may be used to obtain a final output from the system health operations analysis model. The model 600 may include a design, production, and support element 610. The design, production, and support element 610 may include sub-elements such as propulsion, hydraulics, flight controls, avionics, electrical, wiring, ECS, landing gear, and structures for a first and second fleet (depicted as ‘A’ and ‘B’). Other sub-elements may be included in the design, production, and support element 610. Further, sub-elements can also be modified, expanded, or reduced according to the requirements of the model 600. The model 600 may also include a maintenance operations element 620. The maintenance operations may include sub-elements for maintenance man hours, fleet backlog, and other related sub-elements. The model 600 may further include a command and control element 630 including sub-elements such as scenario days, daily flights, schedule rate, and other related sub-elements. Further, the model 600 may include a missions/flights/trips element 640, with sub-elements such as age of aircraft, mission attributes, vehicle condition, mission status and other related sub-elements. Additionally, element 640 may show the number of flights currently taking place, mission/flight reliability, or percentage of scheduled missions/flights that were completed, and number of failures in sub-elements for each fleet throughout a simulation run. The model 600 may also include a fleet management element 650 with sub-elements such as mission backlog, idle vehicles, and other related sub-elements. Some of the sub-elements may be for data input or data display, while some may include a combination of data input and display of data. Additionally, some sub-elements may include data input or display of data for both a first and second fleet while other data input or display of data may only include a single value. For example, in the command and control element 630, the “scenario days” sub-element may only include a single value while the schedule rate may only include data input or display of data for each of the two fleets. The single value typically illustrates a scenario input that is being applied to both fleets. In some embodiments, the system health operations analysis model 600 may run an animation of a fleet comparison. In an example animation process, the “entities” that may enter the mission flight elements are vehicles that have a mission assigned, and therefore contain those mission attributes. Immediately before leaving the missions/flights/trips sub element, the missions and vehicles may be separated and become two distinct entities. The mission entities may then proceed to command and control to determine missions and to tally mission statistics. Last, the vehicles may go back to fleet management for evaluation of maintenance needs. Additionally, the animation speed may be adjusted to increase or decrease the rate of analysis. For example, a researcher or analyst may want to observe the changes in the model over a short period in one study while in another study may want to observe the changes over a number of years. Another entity may be generated in a flight sub-model to represent messages during missions such that they are relayed back to maintenance. For example, using messages, maintainers can start the maintenance preparation without doing actual repairs until the plane's arrival, such as by getting parts in place, researching the problem, etc. Sub-models below the displays may provide logic on the flow of the entities. In FIG. 7, an embodiment of a command and control console of a first and second fleet of vehicles is depicted in environment 700. The command and control console may convey the integration of vehicle health status and mission status into one decision console. Traditionally, maintenance and mission considerations are separate decisions performed by different organizations. The command and control console may be for animation purposes or may be used to collect data reflecting the execution of maintenance and mission operations in other areas of the model. With continued reference to FIG. 7, some embodiments of the command and control console may include a number of elements. A simulated real-time mission status of vehicles may be shown over a world map (or other map) view 702. Portions of the simulation console may change colors, indicating a different status of the simulation run. Additionally, fleet operational metrics may be included in the command and control environment 700. The fleet size of a first and second fleet of vehicles (fleet A and B) 704 may change due to retiring a vehicle after use by a production schedule that allocates vehicle production over time. A graph 706 of operational availability over time may also be included. Operational availability may be one of the primary performance metrics for military fleets to track maintenance performance. The time plot may track the average availability for multiple fleets over time to illustrate relative performance. For purposes of validation and error checking, each fleet's operational availability may be computed using two or more different methods. For example, the operational availability may be the result of the total time minus maintenance time, divided by the total time. Below the operational availability graph may be instantaneous illustrations of operational availability for each fleet 708. These may be the number of vehicles in the fleet that are not in maintenance divided by the total fleet population. Illustrations of the daily sortie generation rate may also be depicted 710. This may be the number of missions, flights, or trips that were achieved by the fleet for the period time period, such as the previous day. This may be updated at the end of each period. On the lower right portion of the command and control environment 700, the flights complete and flights lost may be represented 712. This may also be known as missions complete and missions aborted, respectively. Lost flights and missions aborted means that the vehicle had to end the mission prematurely or divert from the scheduled destination. Additionally, the model may depict vehicle failures that lead to accidents (not shown). A time plot 714 may illustrate the accrual of missions/flights/trips over time. This may be useful in scenarios in which a certain number of missions, flights, or trips need to take place over a period of time. Each fleet may be plotted to illustrate relative performance. Additionally, a number of windows 716 may illustrate the number of vehicles in flight for each fleet and the number of vehicles in maintenance for each fleet. A portion of the screen may also display inputs of the model 718. The command and control environment 700 may include other elements to facilitate animation, research, and analysis of one or more fleet of vehicles. Further, some of the elements described above may not be included in order to simplify the animation, reduce complexity, or achieve other desired results. Embodiments of methods and systems for health operations analysis models in accordance with the present invention may be used to generate a variety of different outputs for analysis. For example, in FIG. 8, an upper chart 810 shows an operational availability sensitivity to manpower, while a lower chart 820 depicts the total maintenance man hours. The charts 810, 820 in environment 800 depict the manpower analysis of a baseline fleet 812, and an upgraded fleet 814 with an advanced diagnostics system that yields an overall average of 10% reduction in repair times. The result may be improved availability given the same number of maintenance personal and costs. This is illustrated in the upper chart 810 that plots the changes in availability and utilization given changes in manpower. On the right side of the upper chart 810, the reduction in manpower results in utilizations approaching 100% (designated generally as 816). In the lower chart 820, availability performance falls dramatically (designated generally as 822) because there are simply too few resources to perform the required maintenance as manning levels are decreased. These charts 810, 820, created from multiple simulation runs of a system health operations analysis model with different manpower levels, demonstrate the sensitivities of the utilization of maintainers and the effects on the fleets' operational availabilities. These charts provide a comparison between a manpower baseline and changes to manpower. The 100% manpower is the maximum quantity of maintainers required at any given time. The quantity is reduced until operational availability drops to zero or maintainer utilization rises to about 100%, thus enabling the identification of the optimum manning level and for the operation of a fleet of vehicles. It should be appreciated that this is just one example of numerous sensitivities that can be charted. In FIG. 9, a prognostics graph 900 is depicted. More specifically, the graph 900 shows the impact of prognostics on availability 910 and mission reliability 920. The event horizon on the x-axis is the average hours of predictive time provided before the failure indication becomes extreme enough to result in significant functional loss or failure. By enabling the elimination of scheduled inspections and removals at conservative time intervals, prognostics may increase component service life. This may enable maintenance to be performed at more opportune times while minimizing interruptions in missions. Certain event horizons can provide significant improvements on the availability of the fleet until its return diminishes. This can show the desired event horizon to maximize the benefits of prognostics. A vast number of other charts and outputs may be created by system health operations analysis models in accordance with the present invention based on the needs of a researcher or analyst. Other outputs from multiple simulation runs may include mission reliability, which is the percentage of successful missions out of the total launched missions. Additionally, operational availability sensitivities may be outputted based on any of the following: changes in mean times between failures, changes in mean times between repairs, changes in scheduled maintenance intervals, percentages of missions that take place in remote sites, and percentages of faults that are forwarded to maintenance while aircrafts are still in the air. It is further contemplated that any of the inputs of the model may be isolated and analyzed for their overall effect on the model. Therefore, every input may reveal information about other inputs, requiring statistical analysis such as regression analysis in order to derive correlations and conclusions from the model. The data outputs incorporate information from both command and control inputs (operations related inputs) and maintenance related inputs, such as maintenance decisions, in order to make comparisons of two fleets of vehicles. FIG. 10 is a flow chart of a model 1000 for aiding in prognostic condition assessment decisions in accordance with yet another embodiment of the invention. The prognostic condition assessment decisions may include simulating real-time decision-making or it may include longer term strategic decision-making integrated into a system health analysis model. For example, in real-time decision-making, an operational controller may decide whether or not a particular flight should occur or whether it should be aborted. Conversely, longer term strategic decision-making integrated in a system health analysis model may apply to the larger operations of flights, and may not include real-time decision-making for individual flights. Further, decision rules may be created to facilitate decision making, either for the real-time occurrences or for the longer term occurrences. At block 1010, data is received relating to a fleet of vehicles for missions and maintenance activity. The fleet of vehicles, as illustrated above in FIG. 4, may be a fleet of airplanes, automobiles, trucks, maritime vessels, weapons, missiles, unmanned aerial vehicles, machinery and equipment used in above-ground or underground mining, buses, trains, railroad equipment, and other types of manned or unmanned mobile platforms. For example, the fleet of vehicles may be a fleet of Boeing 747 airplanes in an existing operational status. Further, the data for missions and maintenance activity may be derived from a number of sources such as actual operational data, mission planning data, maintenance history data, and the like. Some of the data for missions and maintenance activity may be actual data, and some may be hypothetical data. At block 1020, an operational allocation of the fleet is simulated. For example, the inputs at block 1010 are manipulated by a computer program (FIG. 2) to generate a simulation of a fleet of vehicles in operation over a specified period of time. This simulation may include missions, maintenance action, delays, and other events associated with the operations of a fleet of vehicles. At block 1030, the optimum operational allocations are determined. The optimum operation allocations may include any operations which maximize the reliability of missions, reduce the operational costs of the fleet of vehicles, or achieve any other desired result of an operational control group. Further, multiple factors may be weighed in order to achieve a preferred operational allocation. For example, mission reliability and operational costs may be weighed such that an ideal operational allocation results in a desired proportional performance of both factors. Maintenance policies, plans, and decision tools may be developed to aid field decision makers in allocating resources and optimizing usage. At block 1040, the schedules for the fleet of vehicles are generated. The schedules may be generated from the optimum operational allocations which best satisfy the operational control group's requirements. The operational control group may desire to create alternative schedules which provide flexibility upon the occurrence of unforeseen events, such as harsh environmental conditions, maintenance backlogs, higher usage rates, or similar unexpected events which may disrupt the schedules of a fleet of vehicles. FIG. 11 is a flow chart 1100 of another model for aiding in prognostic condition assessment decisions in accordance with another alternate embodiment of the invention. At block 1110 and 1120, input data from a fleet of vehicles is obtained from one or more sources. Block 1110 includes maintenance related data while block 1120 includes mission related data. The data in blocks 1110, 1120 may be used to create prognostic indicators at block 1130. For example, prognostic indicators may include unscheduled events that occur for a fleet of vehicles that may be predicted or statistically modeled. Alternatively, prognostic health indicators may only use maintenance data 1110 or mission requirements 1120. At block 1140, decision criteria are compiled. Decision criteria may include condition based maintenance 1142, fix or fly decisions 1144, and fault forwarding 1146. Additionally, other information, algorithms, statistical models, and the like may be incorporated to create decision criteria for a fleet of vehicles. For example, the decision criteria for a fleet of vehicles may include decisions of when maintenance must be performed on an airplane or when the airplane is able to fly a mission. In an embodiment, the decision criteria may be predetermined computer instructions that make decisions based on a status of a vehicle. Additionally, a user may make decisions, such as to abort a mission or to continue the mission, in a real-time environment. In yet another embodiment, a user may receive feedback from the model 1100 which depicts the results of a real-time decision. At block 1150, mission and maintenance are simulated using at least some of the maintenance data 1110, mission data 1120, prognostic indicators 1130, and decision criteria 1140. In some embodiments, the simulated mission and maintenance 1150 may include other elements, such as operational control group inputs. At block 1160, the optimum allocations are determined based on the simulated allocation. The optimum allocations may be a single allocation of maintenance and missions of a fleet of vehicles, or it may be multiple allocations of the fleet of vehicles, each emphasizing different operational factors, or combination thereof. At block 1170, schedules are generated for the fleet of vehicles based on the optimum allocations of the fleet of vehicles. The optimum allocations 1160 and generated schedules 1170 may be used by operational control groups to aid decisions on allocation of vehicles in a fleet of vehicles to further organizational objectives. Embodiments of methods and systems in accordance with the present invention may provide significant advantages over the prior art. For example, embodiments of the present invention may enable detailed studies of fleets of vehicles to determine cost sensitivities associated with a wide variety of inputs and assumptions. These studies may then be used to focus quality improvement and cost reduction activities to achieve increased benefit. Such studies may also be used to compare fleets of vehicles, including vehicles of the same type under different operating conditions, or vehicles of different types under the same operating conditions. Embodiments of the invention may also advantageously permit various factors to be included in the modeling and analyses of system health operations, including some factors that have not previously been effectively considered or modeled. Ideally, embodiments of the methods and systems for analyzing system health operations in accordance with the present invention may provide improved performance and reduced ownership costs of fleets of vehicles in comparison with the prior art. This analysis capability may not only improve the prior art, but may reduce the overall analysis time and costs, thus reducing overall development costs for vehicles when compared to the prior art. While preferred and alternate embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of these preferred and alternate embodiments. Instead, the invention should be determined entirely by reference to the claims that follow. |
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claims | 1. An optical element, comprising:a substrate;a multilayer film supported on the substrate, the multilayer film reflecting exposure light, the exposure light comprising at least one of extreme ultraviolet radiation and soft X-radiation from source light in a prescribed wavelength region; anda protective layer provided on the multilayer film, the protective layer having a composition preventing oxidation of the multilayer film, the protective layer having an absorption index relative to non-exposure light, other than the exposure light, that is larger than the absorption index of the protective layer relative to the exposure light. 2. The optical element according to claim 1, wherein the non-exposure light comprises at least one of ultraviolet radiation, visible light, and infrared light. 3. The optical element according to claim 1, wherein a material composition of the protective layer changes along a depthwise direction. 4. The optical element according to claim 1, wherein the protective layer has a surface-side layer on its outermost surface side, the surface-side layer being in a state where it is saturated by oxidation, the protective layer also having an interfacial-side layer on its boundary face side adjoining the multilayer film, the boundary face side being in a state where it is unsaturated by oxidation. 5. The optical element according to claim 4, wherein the protective layer has a composition that prevents oxidation of the multilayer film by the surface-side layer. 6. The optical element according to claim 4, wherein the protective layer exhibits relative absorption of the non-exposure light from the source light by the interfacial-side layer. 7. The optical element according to claim 4, wherein the surface-side layer is formed with SiO2, and the interfacial-side layer is formed with SiO. 8. The optical element according to claim 4, wherein the surface-side layer is formed with TiO2, and the interfacial-side layer is formed with TiO. 9. The optical element according to claim 4, wherein the surface-side layer is formed with ZrO2, and the interfacial-side layer is formed with ZrO. 10. The optical element according to claim 4, wherein the protective layer comprises an intermediate layer between the surface-side layer and the interfacial-side layer. 11. The optical element according to claim 10, wherein the intermediate layer comprises at least one of Si, SiO, SiO1.5, and SiO2. 12. The optical element according to claim 1, wherein the multilayer film is formed by alternately laminating on top of the substrate a first layer that is composed of material with a small refractive index difference relative to the refractive index of a vacuum in the extreme ultraviolet ray region, and a second layer that is composed of material with a large refractive index difference. 13. The optical element according to claim 1, wherein the protective layer is situated on top of the first layer that is the topmost layer of the multilayer film. 14. An exposure apparatus, comprising:a light source that generates extreme ultraviolet radiation;an illumination optical system that guides the extreme ultraviolet radiation from the light source to a mask used for pattern transfer; anda projection optical system that forms a pattern image of the mask on a sensitive substrate, whereinat least one of the mask, the illumination optical system, and the projection optical system comprises the optical element according to claim 1. 15. A device manufacturing method comprising a pattern-exposure step performed using the exposure apparatus according to claim 14. |
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claims | 1. A method of removing radioactive internals structural members in the core of a reactor pressure vessel in a containment vessel, the reactor pressure vessel including a core barrel, a lower internals assembly and an upper internals assembly, the method comprising the steps of:removing the core barrel from the reactor pressure vessel;severing the lower internals assembly into an upper section and a lower section;placing a first cask in the lower section of the lower internals assembly, the lower section of the lower internals assembly including radioactive first internals structural members and second internals structural members, the first internals structural members being attached to the second internals structural members;detaching the radioactive first internals structural members from the second internals structural members;placing the detached first internals structural members in the first cask;placing the first cask and the second internals structural members, in a second cask;bracing the first cask within the second cask;placing the upper internals assembly and the severed upper section of the lower internals assembly in a third cask;removing the second cask containing the lower section of the lower internals assembly, the second internals structural members, and the casked detached radioactive first internals structural members from the containment vessel; andremoving the third cask containing the upper internals assembly and the severed upper section of the lower internals assembly from the containment vessel. 2. The method of claim 1 wherein the first internals structural members comprise radioactive baffle plates and the second internals members comprise former plates bolted to the radioactive baffle plates; and wherein the step of detaching the radioactive first internals members from second internals members comprises the step of:unbolting the radioactive baffle plates from the former plates. 3. The method of claim 2 wherein the baffle plates have a plurality of segments; and wherein the step of unbolting the radioactive baffle plates from the former plates comprises the step of:unbolting the baffle plate segments from the former plates. 4. The method of claim 2 wherein the baffle plates are fastened to the former plates by bolts secured by lock bars welded to the baffle plates; and wherein the step of unbolting the radioactive baffle plates from the former plates comprises the steps of:placing a strong back near a baffle plate bolt;placing a tool between the strong back and the baffle plate bolt;placing a pneumatic cavity between the tool and the strong back;expanding the pneumatic cavity to urge the tool into engagement with the baffle plate bolt;cutting or breaking the lock bar securing the baffle plate bolt; andunbolting the baffle plate bolt with the tool. 5. The method of claim 4 wherein the step of placing a strong back near a baffle plate bolt comprises the step of:keying the strong back with the lower internals assembly to precisely position the strong back. 6. The method of claim 1 wherein the lower internals assembly has a plate member disposed at one end of a barrel member; and wherein the step of placing the first cask in the lower internals assembly comprises:placing the first cask on the lower internals assembly plate member in spaced relationship from the barrel member. 7. The method of claim 6 wherein the lower internals assembly plate member has guide members; wherein the first cask has a base plate member; and wherein the step of placing the first cask on the lower internals assembly plate member and in spaced relationship from the barrel member comprises:lowering the first cask base plate member over the guide members. 8. The method of claim 7 wherein the first cask has a number of detachable side wall members; and wherein the step of placing the detached first internals structural members in the first cask comprises:placing the detached first internals structural members on the first cask base plate member after the first cask base plate member is lowered over the guide members; andattaching the number of first cask detachable side wall members to the first cask base plate member after the detached first internals structural members have been placed on the first cask base plate member. 9. The method of claim 1, further comprising:draining water from the first cask in the lower internals assembly. 10. The method of claim 1, further comprising:positioning indexable guides in the first cask proximate the detached first members. 11. The method of claim 1 wherein the first cask and the second cask each have a wall thickness; and wherein the wall thickness of the first cask is greater than the wall thickness of the second cask. 12. The method of claim 11 wherein the wall thickness of the first cask is at least twice the wall thickness of the second cask. 13. The method of claim 1 wherein the first cask and the second cask are made from substantially similar materials of construction. 14. The method of claim 1, wherein the detached first internals members have radiation contact levels of at least 500,000 R/hr; and wherein the second cask has an outside surface with a radiation level of about 800 mR/hr. or less. 15. The method of claim 1, further comprising:placing the upper internals assembly into the severed upper section of the lower internals assembly;placing the severed upper section of the lower internals assembly containing the upper internals assembly into the third cask; andremoving the third cask containing the severed upper section of the lower internals assembly and the upper internals assembly from the containment vessel. 16. The method of claim 15 wherein the upper internals assembly has extending members; and wherein the method further comprises:severing the extending members from the upper internals assembly before the step of placing the upper internals assembly in the third cask. 17. The method of claim 1 wherein the first cask further comprises a plurality of radial arms structured to extend radially outwardly from the first cask; and wherein the method further comprises:extending the radial arms to engage the lower internals assembly, thereby stabilizing the first cask within the lower internals assembly and the second cask. |
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summary | ||
description | 1. Field of the Invention The present invention relates generally to rear door systems for transferring hot cell equipment, and, more particularly, to a rear door system for transferring hot cell equipment which has an improved structure such that a vertical moving table is vertically moved on the rear door of a large hot cell that handles highly radioactive material but cannot have a roof door, so that an operation of transferring the hot cell equipment, which is relatively large or heavy and is highly radioactive, into or out of the hot cell can be conducted using only the rear door, thus making it easy to transfer the hot cell equipment, and preventing a user from being directly exposed to radiation, thereby preventing the user from being subjected to safety hazards that may occur when transferring the hot cell equipment. 2. Description of the Related Art As well known to those skilled in the art, large hot cells, which handle highly radioactive material, include rear doors and roof doors. Here, in the case of hot cell equipment which is relatively small and light and has relatively low radioactivity, the rear door is opened, and then the hot cell equipment is carried into or out of the hot cell therethrough. In the case of hot cell equipment which is relatively large and heavy and has relatively high radioactivity, the roof door is opened and, thereafter, the hot cell equipment is carried into or out of the hot cell therethrough using a crane, which is provided in a service area. Meanwhile, of the hot cells that handle highly radioactive material, in the case of a hot cell which has no roof door, the hot cell equipment, which is relatively large and heavy and has relatively high radioactivity, cannot be carried into the hot cell. Thus, in the case where there is no roof door, only hot cells that handle radiation material that is relatively small and have relatively low radioactivity have been constructed. As such, of the hot cells that handle highly radioactive material, in the case of a hot cell which is provided with a rear door but has no roof door, all of the hot cell equipment is carried into or out of the hot cell through the rear door. Here, in the case of the large hot cell which handles highly radioactive material, radiation shielding walls constituting the hot cell are very thick. Therefore, in space defined by the rear door and areas adjacent to the corresponding radiation shielding wall, there are some areas that a crane in the hot cell and a crane in the service area cannot approach. Hence, there is a problem in that it is difficult to carry the hot cell, which is heavy or large, into or out of the hot cell. Furthermore, typically, the height of a hot cell working table, which is installed in the hot cell, is 900 mm, and the height of an opening defined by the rear door is 2000 mm. Therefore, the height of a space between the upper end of the opening, defined by the rear door, and the hot cell working table is 1100 mm. However, taking the curved edge of the working table into account, the effective space between the upper end of the opening and the working table is less than 1100 mm. Therefore, it also is very difficult to carry the hot cell equipment, which is large or heavy, into or out of the hot cell. In addition, in the case of hot cell equipment which is small and light but has high radioactivity, there is a problem in that a user may be exposed to large amounts of radiation. Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a rear door system for transferring hot cell equipment which has an improved structure such that a vertical moving table is vertically moved on the rear door of a large hot cell that handles highly radioactive material but cannot have a roof door, so that an operation of transferring the hot cell equipment, which is relatively large or heavy and is highly radioactive, into or out of the hot cell can be conducted using only the rear door, thus making it easy to transfer the hot cell equipment, and preventing a user from being directly exposed to radiation, thereby preventing the user from being subjected to safety hazards that may occur when transferring the hot cell equipment. In order to accomplish the above object, the present invention provides a rear door system for transferring hot cell equipment into or out of a hot cell, including: a rear door provided to a rear wall of the hot cell so as to be movable to open or close the rear wall of the hot cell; a vertical moving table provided at a predetermined position on a lower portion of a front surface of the rear door so as to be movable upwards or downwards; a drive unit provided at a predetermined position in a lower end of the rear door to move the rear door; a stationary working table disposed above the vertical moving table and fixed in the hot cell in a horizontal orientation; a removable table removably coupled at a predetermined position to the stationary working table; and a hot cell crane hook and a service area crane hook respectively provided inside and outside the hot cell. Preferably, guide rails may be vertically provided at respective predetermined opposite positions on the lower portion of the front surface of the rear door. Furthermore, the vertical moving table may include: a ball screw provided through an end of the vertical moving table so as to be rotatable; support members provided on respective opposite ends of the ball screw and fastened at respective predetermined positions to the front surface of the rear door; a ball nut coupled to the ball screw so as to be movable upwards or downwards; a bevel gear provided on a lower end of the ball screw; a shaft gear engaging with the bevel gear in a horizontal direction; a rotating shaft coupled at an end thereof to the shaft gear and provided so as to be rotatable; and a moving table driving motor coupled to the rotating shaft. In addition, at least one rail block may be provided at each of predetermined opposite positions on a rear surface of the vertical moving table. As well, a receiving space having a predetermined size corresponding to a size of the removable table may be formed at a predetermined position through the stationary working table. Preferably, a plurality of steel plates, which are attracted by magnetic force, may be provided in an upper surface of the removable table. Furthermore, a plurality of reinforcing bars may be horizontally provided under a lower surface of the removable table at positions spaced apart from each other in a longitudinal direction at predetermined intervals. As well, a magnet may be provided on the hot cell crane hook. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a front view schematically showing a rear door system for transferring hot cell equipment, according to an embodiment of the present invention. FIG. 2 is a rear view schematically showing the rear door system for transferring the hot cell equipment. FIG. 3 is a side view schematically showing the rear door system for transferring the hot cell equipment. FIG. 4 is a sectional view taken along the line A-A′ of FIG. 3. FIG. 5 is a sectional view taken along the line B-B′ of FIG. 3. FIG. 6 is an enlarged view of the circled portion C of FIG. 3. FIG. 7 is a side view showing a vertical moving table of the rear door system for transferring the hot cell equipment. FIGS. 8, 9 and 10 are views illustrating the operation of the rear door system for transferring the hot cell equipment. As shown in the drawings, the rear door system 1 for a hot cell for transferring the hot cell equipment according to the present invention includes a rear door 10, a vertical moving table 20, a drive unit 30, a stationary working table 40, a removable table 50, a hot cell crane hook 60, and a service area crane hook 60′. The rear door 10 is openably coupled to a rear wall 3 of a hot cell to carry the hot cell equipment 8 into or out of the hot cell. Two guide rails 11 are vertically provided on the lower portion of the front surface of the rear door 10 at predetermined respective positions opposite each other. Furthermore, two clamps 15 are provided at predetermined positions on the respective opposite edges of the rear surface of the rear door 10. The clamps 15 serve to fasten the rear door 10 to the rear wall 3 of the hot cell for safety under normal conditions. The vertical moving table 20 is coupled at a predetermined position to the lower portion of the front surface of the rear door 10 so as to be movable upwards and downwards along the guide rails 11, which are vertically provided on the lower portion of the front surface of the rear door 10. To make it possible for the vertical moving table 20 to vertically move along the guide rails 11 of the rear door 10, at least one rail block 28 is provided on the rear surface of the vertical moving table 20, so that the vertical moving table 20 is movably coupled to the guide rails 11 by the rail block 28. In the embodiment of the present invention, although two rail blocks 28 are provided at each of opposite positions on the rear surface of the vertical moving table 20, more than two or less than two rail blocks 28 may be provided at each of predetermined positions on the rear surface of the vertical moving table 20, so long as the vertical moving table 20 can be coupled to the guide rails 11, which are provided on the front surface of the rear door 10, so as to be easily movable upwards and downwards. As such, the vertical moving table 20 is vertically movable on the front surface of the rear door 10 by coupling the rail blocks 28 of the vertical moving table 20 to the guide rails 11, which are provided at respective opposite positions on the lower portion of the front surface of the rear door 10. Meanwhile, a ball screw 21 is provided through the end of the vertical moving table 20 so as to be rotatable. Support members 22 are provided on respective opposite ends of the ball screw 21. The support members 22 are fastened at predetermined positions to the front surface of the rear door 10. Furthermore, a ball nut 23, the upper end of which is coupled to the lower surface of the vertical moving table 20, is fitted over the ball screw 21 so as to be movable upwards or downwards depending on the rotation of the ball screw 21. Here, a bevel gear 24 is provided on the lower end of the ball screw 21. The bevel gear 24 engages with a shaft gear 25 of a rotating shaft 26 which is rotatably coupled to the center of the end of a moving table driving motor 27. In the above-mentioned construction, the rotating shaft 26, which is coupled to the moving table driving motor 27, is rotated by the operation of the moving table driving motor 27. The shaft gear 25 is rotated by the rotation of the rotating shaft 26. Then, the bevel gear 24 is rotated by the rotation of the shaft gear 25, thus rotating the ball screw 21. Thus, the ball nut 23, which is provided on the ball screw 21, is moved upwards or downwards by the rotation of the ball screw 21. Thereby, the vertical moving table 20, which is coupled to the upper end of the ball nut 23, is moved upwards or downwards. The drive unit 30 is provided at a predetermined position in the lower end of the rear door 10 to move the rear door 10. To achieve the above-mentioned purpose, the drive unit 30 includes a drive motor 31, a drive gear 32, which is provided on the lower end of the drive motor 31, a bevel gear 33, which engages with the drive gear 32, and a central shaft 34, which is coupled to the center of the bevel gear 33. The drive unit 30 further includes rear drive wheels 35, which are coupled to respective opposite ends of the central shaft 34 so as to be rotatable, and front wheels 36, which are provided ahead of the rear drive wheel 35. Here, support guide rails 7 are provided at predetermined opposite positions on a support bottom, which extends from the lower surface of the rear wall 3 of the hot cell. The rear drive wheels 35 are placed on the respective support guide rails 7 so as to be movable forwards or backwards along the support guide rails 7. Meanwhile, a dog 13 is provided at a predetermined position on the rear surface of the rear door 10. In addition, a limit switch 5 is provided on the rear wall 3 of the hot cell at a position corresponding to the dog 13. The dog 13 and the limit switch 5 are constructed such that they can come into contact with each other. When the dog 13 comes into contact with the limit switch 5, the drive motor 31 of the drive unit 30 is turned off, so that the rear door 10 is stopped. The stationary working table 40 is disposed above the vertical moving table 20 and is horizontally fixed in the hot cell. The stationary working table 40 is made of a typical stainless steel plate and is fixed to the upper end of a support structure (not designated by a reference numeral), which is placed on the bottom in the hot cell. The removable table 50 is removably coupled at a predetermined position to the stationary working table 40. Furthermore, the removable table 50 is attached to a magnet 61 of the hot cell crane hook 60, which is provided in the hot cell, by the magnetic force of the magnet 61 and is moved upwards or downwards by the operation of the hot cell crane hook 60. In other words, the removable table 50 is removably coupled at the predetermined position to the stationary working table 40. For this, a receiving space 41 for installation of the removable table 50 is formed at the predetermined position through the stationary working table 40. Here, a plurality of steel plates 51, which are attracted by the magnetic force of the magnet 61, is inserted in the upper surface of the removable table 50. In other words, the steel plates 51, which are provided in the upper surface of the removable table 50, become attached to the magnet 61 of the hot cell crane hook 60 by magnetic force, so that the removable table 50 is attached to or removed from the stationary working table 40 by operating the hot cell crane hook 60 having the magnet 61. Furthermore, several reinforcing bars 53 for reinforcing the removable table 50 are horizontally provided under the lower surface of the removable table 50 at positions spaced apart from each other in a longitudinal direction at predetermined intervals. As such, because the steel plates 51 are provided in the removable table 50, a process of attaching or removing the removable table 50 to or from the stationary working table 40 can be easily conducted using the magnet 61 of the hot cell crane hook 60. Furthermore, the removable table 50 is reinforced with several reinforcing bars 53. Thanks to the reinforcing bars 53, the removable table 50 is prevented from sagging. Hereinafter, the operation of the rear door system for transferring the hot cell equipment according to the present invention will be explained herein below with reference to FIGS. 8, 9 and 10. First, when it is desired to carry the hot cell equipment 8 out of the hot cell using the rear door system 1 of the present invention, the magnet 61 is hung on the hot cell crane hook 60 and, thereafter, the hot cell crane hook 60 is moved downwards such that the magnet 61 provided on the end of the hot cell crane hook 60 is disposed on the upper surface of the removable table 50. Then, the removable table 50 is attached to the magnet 61 by the magnetic force of the magnet 61. After the removable table 50 is attached to the magnet 61 of the hot cell crane hook 60, the hot cell crane hook 60 is moved upwards to remove the removable table 50 from the stationary working table 40. Subsequently, the magnet 61 and the removable table 50, which is attached to the magnet 61 using the magnetic force, are removed from the hot cell crane hook 60. Thereafter, the hot cell equipment 8, which is placed in the hot cell, is held by the hot cell crane hook 60 and is moved into the space in which the removable table 50 was disposed, that is, the receiving space 41 of the stationary working table 40. Then, the hot cell equipment 8 is placed on the upper surface of the vertical moving table 20, which is disposed below the stationary working table 40. As such, after the hot cell equipment 8 has been placed on the vertical moving table 20, the drive unit 30, which is provided in the lower end of the rear door 10, is operated to move the rear door 10 out of the hot cell. To move the rear door 10, the drive motor 31 of the drive unit 30 is operated, and then the drive gear 32, which is provided on the lower end of the drive motor 31, is rotated. Thus, the bevel gear 33, which engages with the drive gear 32, is rotated by the rotation of the drive gear 32. Then, the central shaft 34, which is coupled to the center of the bevel gear 33, and the rear drive wheels 35, which are provided on the opposite ends of the central shaft 34, are rotated by the rotation of the bevel gear 33. As a result, the rear door 10 is moved. Here, when the rear drive wheels 35, which are provided under the rear door 10, are rotated, the front wheels 36, which are disposed ahead of the rear drive wheels 35, are rotated along with the rear drive wheels 35 to move the rear door 10. Furthermore, when the rear door 10 is moved forwards or backwards by the drive unit 30, the rear drive wheels 35 are moved along the respective support guide rails 7, which are provided at predetermined opposite positions on the support bottom both in an opening of the rear wall 3 of the hot cell and in a service area. As such, after the rear door 10 is moved along the support guide rails 7 and is spaced apart from the rear wall 3 of the hot cell by a predetermined distance, the hot cell equipment 8, which is placed on the upper surface of the vertical moving table 20, is held by a service area crane hook 60′, which is disposed in the service area outside the hot cell, and is moved to a desired location. In the present invention, the vertical position of the hot cell equipment 8, which is placed on the upper surface of the vertical moving table 20, can be adjusted. In detail, depending on the size or height of the hot cell equipment 8 that is placed on the upper surface of the vertical moving table 20, the vertical position of the hot cell equipment 8 can be adjusted by vertically moving the vertical moving table 20. To achieve the above-mentioned purpose, the moving table driving motor 27 is operated, so that the rotating shaft 26, which is coupled to the center of the end of the moving table driving motor 27, is rotated. Thus, the shaft gear 25, which is coupled to the end of the rotating shaft 26, is rotated by the rotation thereof, and the bevel gear 24, which engages with the shaft gear 25, is rotated by the rotation of the shaft gear 25. Thereby, the ball screw 21 is rotated, so that the ball nut 23, which is provided on the ball screw 21, is moved upwards or downwards by the rotation of the ball screw 21. As a result, the vertical moving table 20, which is coupled to the upper end of the ball nut 23, is moved upwards or downwards, thus adjusting the vertical position of the hot cell equipment 8. After the hot cell equipment 8 is moved to the service area crane hook 60′ from the vertical moving table 20 of the rear door 10, which has been moved into the service area outside the hot cell through the above-mentioned process, the rear door 10 is moved to the rear wall 3 of the hot cell again. At this time, the movement of the rear door 10 towards the rear wall 3 of the hot cell is conducted in the order reverse to that of the above operating process. When the dog 13, which is provided at a predetermined position on the upper end of the rear door 10, comes into contact with the limit switch 5, which is provided on the rear wall 3 of the hot cell at the position corresponding to the dog 13, the movement of the rear door 10 is stopped. For this, the dog 13, which is provided on the upper end of the rear door 10, is connected to the drive unit 30, which is provided in the lower end of the rear door 10. In other words, the drive unit 30, which moves the rear door 10, is connected to the dog 13, which is provided on the upper end of the rear door 10 and is set such that, when the rear door 10 is closed to the rear wall 3 of the hot cell, the dog 13 is brought into contact with the limit switch 5. Furthermore, when the dog 13 is brought into contact with the limit switch 5, the dog 13 stops the operation of the drive unit 30. Therefore, every time the rear door 10 is closed, it can be precisely disposed at the same position in the rear wall 3 of the hot cell. As described above, a rear door system for transferring hot cell equipment according to the present invention has an improved structure in which a vertical moving table is vertically moved on the rear door of a large hot cell that handles highly radioactive material but cannot have a roof door. Thus, an operation of transferring the hot cell equipment, which is relatively large or heavy and is highly radioactive, into or out of the hot cell can be conducted using only the rear door. Therefore, the present invention can make it easy to transfer the hot cell equipment and prevent a user from being directly exposed to radiation, thus preventing the user from being subjected to safety hazards that may occur when transferring the hot cell equipment. Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. |
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051877260 | claims | 1. An X-ray lithography mask comprising: (a) a carrier of thin material which does not substantially attenuate X-rays passed therethrough and having top and bottom surfaces; (b) at least one phase shifting feature formed on a surface of the carrier, the feature defined by a region of X-ray phase shifting material of a height selected such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the X-rays, the feature having at least one sharply defined sidewall which is substantially upright with respect to the surface of the carrier, wherein the material forming the feature on the mask is PMMA. a carrier of thin material which does not substantially attenuate X-rays passed therethrough and having top and bottom surfaces; (b) at least one phase shifting feature formed on a surface of the carrier, the feature defined by a region of X-ray phase shifting material of a height selected such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the X-rays, the feature having at least one sharply defined sidewall which is substantially upright with respect to the surface of the carrier, wherein the feature formed on the carrier has, in addition to the upright sidewall, at least one sidewall which is slanted at an angle with respect to the surface of the carrier. (a) a carrier of thin material which does not substantially attenuate X-rays passed therethrough and having top and bottom surfaces; (b) at least one phase shifting feature formed on a surface of the carrier, the feature defined by a region of X-ray phase shifting material of a height selected such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the X-rays, the feature having at least one sharply defined sidewall which is substantially upright with respect to the surface of the carrier; and (c) further including at least one spacer formed on the surface of the carrier, the spacer selected from the group of materials which provides substantially no phase shift of X-rays passed therethrough or of a height selected to introduce a full wave phase shift of X-rays passed therethrough or multiples thereof, and wherein there are a plurality of phase shifting features formed of phase shifting material, at least one of the features formed directly on the surface of the carrier and at least one of the features formed on the spacer, whereby when X-rays are passed through the X-ray lithography mask, the patterns formed in a target photoresist under the phase shifting feature on the spacer will be broader than the structures formed in the target photoresist under the phase shifting feature which is on the surface of the carrier. (a) a phase shift mask having: (b) a target comprising a layer of photoresist on a substrate, the target photoresist having a top surface spaced closely beneath the phase shift mask and separated therefrom by a gap less than about fifteen micrometers; and further including at least one spacer formed on the surface of the carrier, the spacer selected from the group of materials which provides substantially no phase shift of X-rays passed therethrough or of a height selected to introduce a full wave phase shift of X-rays passed therethrough or multiples thereof, and wherein there are a plurality of phase shifting features formed of phase shifting material, at least one of the features formed directly on the surface of the carrier and at least one of the features formed on the space, whereby when X-rays are passed through the X-ray lithography mask, the patterns formed in the target photoresist under the phase shifting feature on the spacer will be broader than the structures formed in the photoresist under the phase shifting feature which is on the surface of the carrier. (a) providing an X-ray lithography mask having a carrier of thin material which does not substantially attenuate X-rays passed therethrough and having top and bottom surfaces, at least one phase shift feature formed on the surface of the carrier defined by a region of phase shifting material of a height such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the X-rays and the phase shifting material is substantially transparent to the X-rays, the feature having at least one sharply defined sidewall which is substantially upright with respect to the surface of the carrier; (b) providing a target of a layer of X-ray sensitive photoresist on a substrate and positioning the target under the mask and spaced therefrom by a small gap; (c) passing a beam of substantially collimated X-rays through the mask onto the target to result in substantially complete exposure of the target photoresist in regions thereof that are adjacent to the regions under the sidewall of the phase shift feature including the region under the phase shift feature and with sufficiently low exposure of the target photoresist in the region underlying the upright sidewall of the phase shift feature due to interference effects that the photoresist in such region will not be developed by a photoresist developer; and (d) developing the target photoresist to remove the fully exposed resist and to leave thin wall structure on the substrate which had been under the upright sidewall of the phase shift feature on the mask. (a) providing an absorber X-ray mask comprising a carrier and an absorber laid thereon in a pattern corresponding to the desired pattern in the phase shift mask; (b) passing a beam of substantially collimated X-rays through the absorber mask and onto a photoresist on a phase shift mask carrier spaced closely underneath the mask to expose the resist in all regions outside of the shadow of the absorber and to leave the resist material in the shadow of the mask unexposed, the height of the photoresist selected such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the selected band of X-rays to which the photoresist and carrier are substantially transparent; (c) developing the photoresist material on the phase shift mask carrier surface to remove the exposed material and leave the unexposed material in the desired pattern corresponding to the phase shift feature on the phase shift mask. (a) a phase shift mask having: (b) a target comprising a layer of photoresist on a substrate, the target photoresist having a top surface spaced closely beneath the phase shift mask and separated therefrom by a gap, the photoresist selected such that when the selected ban of X-rays is passed through the phase shifting feature the photoresist will be substantially completely exposed under the phase shifting feature except at regions under the upright sidewall. (a) a phase shift mask having: (b) a target comprising a layer of photoresist on a substrate, the target photoresist having a top surface spaced closely beneath the phase shift mask and separated therefrom by a gap less than about fifteen micrometers, wherein the feature formed on the carrier has, in addition to the upright sidewall, at least one sidewall which is slanted at an angle with respect to the surface of the carrier. (a) a phase shift mask having: (b) a target comprising a layer of photoresist on a substrate, the target photoresist having a top surface spaced closely beneath the phase shift mask and separated therefrom by a gap less than about fifteen micrometers, wherein the material forming the feature on the mask is PMMA. (a) providing an X-ray lithography mask having a carrier of thin material which does not substantially attenuate X-rays passed therethrough and having top and bottom surfaces, at least one phase shift feature formed on the surface of the carrier defined by a region of phase shifting material of a height such that a selected band of X-rays passed therethrough is phase shifted by substantially one-half wavelength of the X-rays and wherein the phase shift material is substantially transparent to the X-rays, the feature having at least one sharply defined sidewall which is substantially upright with respect to the surface of the carrier; (b) providing a target of a layer of X-ray sensitive photoresist on a substrate and positioning the target under the mask and spaced therefrom by a small gap; (c) passing a beam of X-rays through the mask onto the target to result in substantially complete exposure of the target photoresist in regions thereof that are adjacent to the regions under the sidewall of the phase shift feature including the region under the phase shift feature and with low exposure of the target photoresist in the region underlying the upright sidewall of the phase shift feature due to interference effects; and (d) developing the target photoresist with a developer for the photoresist. 2. The X-ray lithography mask of claim 1 further including an X-ray absorbing material formed in a pattern on the surface of the carrier, the material forming the phase shifting feature having a portion thereof overlying the X-ray absorbing material. 3. The X-ray lithography mask of claim 1 wherein the feature has a height above the carrier of about 2.5 to 3.0 micrometers. 4. The X-ray lithography mask of claim wherein the carrier is formed of silicon nitride having a thickness of about 1 micrometer or less. 5. AN X-ray lithography mask comprising: 6. The X-ray lithography mask of claim 5 wherein the material forming the phase shift feature is partially absorbent of X-rays passed therethrough. 7. An X-ray lithography mask comprising: 8. An X-ray lithography mask and target set comprising: 9. A method of producing microstructures by X-ray lithogrpahy comprising: 10. The method of claim 9 wherein the gap between the mask and the target photoresist is ten micrometers or less. 11. The method of claim 9 wherein the step of passing a beam of substantially collimated X-rays is carried out by providing X-rays from a synchrotron and passing the X-ray flux from the synchrotron through the mask to the target photoresist. 12. The method of claim 9 wherein the target photoresist is formed of PMMA. 13. The method of claim 9 wherein the photoresist has a sharply defined resist exposure threshold and wherein the region in the target resist underlying the vertical sidewall of the phase shift feature receives less than the exposure threshold of the resist whereas the regions adjacent thereto receive greater exposure than the X-ray exposure threshold resist so as to provide, after developing of the exposed photoresist, sharply defined thin wall structures formed by the remaining photoresist on the 14. The method of claim 9 wherein the mask includes at least one phase shift feature having at least one upright sidewall and, in addition to the upright sidewall, at least one sidewall which is slanted with respect to the carrier so that no significant interference effects take place under the slanted sidewall as the X-rays are passed therethrough and wherein all of the photoresist under the slanted sidewall in the target photoresist is removed by the developer. 15. The method of claim 14 wherein the feature having a slanted sidewall has two slanted sidewalls which intersect and define the ends of an upright sidewall so that after passing the X-rays through the mask and developing the photoresist, an isolated open thin wall structure formed of the undeveloped photoresist is left remaining on the substrate. 16. The method of claim 9 wherein the X-ray mask further includes an X-ray absorber formed in a pattern on the surface of the carrier and wherein the material of the phase shift feature has a portion thereof which overlies the absorber structure, such that when X-rays are passed through the X-ray mask, the areas in the target resist under the absorber and under the upright sidewalls of the phase shift feature receive a low X-ray exposure and are left on the substrate after the target resist is developed. 17. The method of claim 9 wherein the mask further includes at least one spacer formed on the surface of the carrier which has essentially no phase shift of X-rays passed therethrough or has a selected of a height which introduces a full wave phase shift or multiples thereof of X-rays passed therethrough, and wherein there are a plurality of phase shifting features at least one of which is formed on top of the spacer and one is formed directly on the carrier surface, such that after X-rays are passed through the mask, those portions of the target resist underlying the upright sidewalls of the feature on the spacer leave broader wall structures on the substrate than those portions of the target resist underlying the upright sidewalls of the feature formed directly on the carrier surface. 18. The method of claim 9 wherein the material of the phase shift feature partially absorbs the X-rays pass therethrough. 19. The method of claim 9 wherein the carrier of the mask is formed of silicon nitride having a thickness of about one micrometer or less. 20. The method of claim 9 wherein the material of the phase shift feature on the mask is formed on PMMA. 21. The method of claim 20 wherein the feature has a height above the carrier surface of 2.5 to 3 micrometers. 22. A method of making an X-ray lithography phase shift mask comprising the steps of: 23. The method of claim 22 wherein the photoresist is PMMA. 24. The method of claim 22 wherein the X-rays are passed through the mask at an angle to the surface of the carrier of the mask to cast a shadow of the absorber in the photoresist material which is at an angle to the carrier of the phase shift mask, so that when the resist material is developed, the phase shift feature formed by the unexposed resist has slanted sidewalls corresponding to the angle of incidence of the X-rays passing through the absorber mask into the photoresist. 25. An X-ray lithography mask and target set comprising: 26. The X-ray lithography mask and target set of claim 25 wherein the height of the phase shifting feature is selected to provide substantially a one-half wavelength phase shift of a region of X-rays passed therethrough which interact the most with the target photoresist. 27. The X-ray lithography mask and target set of claim 25 wherein the feature has a height above the carrier of about 2.5 to 3.0 micrometers. 28. The X-ray lithography mask and target set of claim 25 wherein the carrier is formed of silicon nitride having a thickness of about 1 micrometer or less. 29. The X-ray lithography mask and target set of claim 25 wherein the material forming the phase shift feature is partially absorbent of X-rays passed therethrough. 30. The X-ray lithography mask and target set of claim 25 further including an X-ray absorbing material formed in a pattern on the surface of the carrier, the material forming the phase shifting feature having a portion thereof overlying the X-ray absorbing material. 31. An X-ray lithography mask and target set comprising: 32. An X-ray lithography mask and target set comprising: 33. A method of producing microstructures by X-ray lithography comprising: 34. The method of claim 33 wherein the X-ray mask further includes an X-ray absorber formed in a pattern on the surface of the carrier and wherein the material of the phase shift feature has a portion thereof which overlies the absorber structure, such that when X-rays are passed through the X-ray mask, The areas in the target resist under the absorber and under the upright sidewalls of the phase shift feature receive a low X-ray exposure. 35. The method of claim 34 wherein the gap between the mask and the target photoresist is ten micrometers or less. 36. The method of claim 34 wherein the mask includes at least one phase shift feature having at least one upright sidewall and, in addition to the upright sidewall, at least one sidewall which is slanted with respect to the carrier so that no significant interference effects take place under the slanted sidewall as the X-rays are passed therethrough. 37. The method of claim 36 wherein the feature having a slanted sidewall has two slanted sidewalls which intersect and define the ends of an upright sidewall. |
description | This application claims the benefit of U.S. Provisional Application No. 62/945,587 filed Dec. 9, 2019, which is incorporated herein by reference in its entirety. The present invention relates generally to systems and apparatuses for storing high level radioactive waste such as used or spent nuclear fuel (SNF), and more particularly to an improved system comprising a nuclear fuel basket with integral shims. In the operation of nuclear reactors, the nuclear energy source is in the form of hollow Zircaloy tubes filled with enriched uranium, collectively arranged in multiple assemblages referred to as fuel assemblies. When the energy in the fuel assembly has been depleted to a certain predetermined level, the used or “spent” nuclear fuel (SNF) assemblies are removed from the nuclear reactor. The standard structure used to package used or spent fuel assemblies discharged from light water reactors for off-site shipment or on-site dry storage is known as the fuel basket. The fuel basket is essentially an assemblage of prismatic storage cells each of which is sized to store one fuel assembly that comprises a plurality of individual spent nuclear fuel rods. The fuel basket is arranged inside a cylindrical metallic fuel storage canister, which is often referred to as a multi-purpose canister (MPC) that forms the primary nuclear waste containment barrier. Such MPCs are available from Holtec International of Camden, N.J. The fuel assemblies are typically loaded into the canister while submerged in the spent fuel pool of the reactor containment structure to minimize radiation exposure to personnel. The typical prismatic structure of the fuel basket used to store the SNF comprises openings or cells; each of which houses a single fuel assembly as previously noted. The cells have a square cross-sectional shape to match the configuration of U.S. type PWR (Pressurized Water Reactor) fuel assemblies. The fuel basket walls may be made by stacking and mechanically interlocking slotted plates together which are arranged in an orthogonal pattern to achieve the desired height. All of the exterior plates are typically welded together to structurally stabilize the stack. The resultant cells may have a square cross-sectional shapes to match the configuration of U.S. type PWR (Pressurized Water Reactor) fuel assemblies. FIGS. 1 and 2A show a typical fuel basket structure having a plurality of undulating planar stepped side walls surfaces formed by the exterior outboard slotted plates. The basket has a compound rectilinear polygonal prismatic perimeter in top down view; however, the nuclear waste canister has a circular shell wall causing a profile mismatch. Accordingly, some means is required to compensate for dimensional and profile differences at the peripheral fuel basket to canister interface in order to center and stabilize the basket within the canister for handling and transport without damaging the fuel assemblies contained therein. In one prior approach, the fuel basket is first positioned inside the metallic cylindrical canister and thereafter laterally centered therein by multiple so-called “loose” extruded basket shims. FIG. 2B shows such loose basket shims comprise multiple individual tubular extrusions of various complex and compound cross-sectional shapes each forming an enclosed central cavity or space. The extrusions are inserted into the many differently configured lateral gaps or pockets formed between the stepped lateral exterior surfaces of the fuel basket and the cylindrical inner surface of the canister. The entire peripheral gap is typically filled with the loose shims as shown, requiring many individual and custom made cross-sectional shapes of shim tubes to achieve this as shown. The prior use of unattached extruded loose shim tubes alone however has several fabrication and performance drawbacks. First, the fuel basket rejects the decay heat emitted by the used or spent nuclear fuel assemblies to the outer canister shell via the loose basket shims which serve as a heat conduction bridge. In theory, the heated canister shell in turn then emits the heat to the immediate surrounding environment to cool the canister and fuel assemblies. Without direct coupling of the tubular shims to fuel basket plates, however, thermal conduction is not as effective as desired. The tubular shaped shim extrusions with solid walls further block a straight line of sight between the exterior surfaces of the fuel basket and the interior surface of the cylindrical canister. This blocks a radiant heat transfer path from the basket directly to the canister, which detrimentally reduces overall heat transfer effectiveness required to cool the fuel assemblies to prevent their structural degradation. Accordingly, because the heat rejection rate is limited by the loose extruded shims and the canister diameter is standardized to fit within a radiation shielded overpack or cask, a restriction is imposed on the size of the fuel basket and concomitantly the number of fuel assemblies which can be stored therein to keep the assembles from overheating. Secondly, as is further apparent in FIG. 2B, multiple sizes of shims with various cross-sectional shapes must be fabricated to accommodate both different diameter fuel baskets (i.e. lateral width dimensions in all lateral directions), and the many differently configured cross-sectional shaped gaps formed between the basket periphery and canister. Such a full set of shims of various dimensions and shapes for a single basket and canister assembly are obviously quite costly to manufacture. Finally, the “loose” extruded tubular shims do not structurally reinforce or stiffen the fuel basket itself because there is no solid fixation of the shims to the slotted plate walls of the basket. When the basket is therefore lifted and handled for insertion into the fuel canister, the basket is susceptible to damage if banged against the canister or outright dropped to the floor. Accordingly, there remains a need for improvements in supporting, stabilizing, and centering fuel baskets in SNF canisters. The present application discloses a nuclear fuel storage system including a canister and fuel basket with integral fuel basket shimming system. The present system is economical to manufacture and overcomes the drawbacks of using the foregoing prior individual “loose” shims alone to fill the many different size and shaped peripheral gaps formed between the fuel basket exterior side surfaces and the cylindrical fuel storage canister. The present basket shimming system advantageously provides a mechanical support system which directly reinforces the fuel basket structurally separate from the canister to avoid damage when inserting the basket therein, and laterally centers and stabilizes the basket in the canister to resist movement and damage during seismic events. In addition, the present integral fuel basket shimming system improves the nuclear fuel assembly heat rejection rate by providing unobstructed straight lines of sight between the lateral exterior side surfaces of the fuel basket and the canister shell for efficient radiant heat transfer. This direct radiant heat rejection path established between the fuel basket and canister advantageously protects the structural integrity of the fuel assembles better. Moreover, larger capacity fuel baskets holding a greater number of fuel assemblies can accordingly be stored in a single canister due to the improved heat rejection rates obtainable. In one implementation, a fuel basket incorporating the present shimming system generally comprises a plurality of interlocked and orthogonally intersecting slotted plates. The plates are built up in horizontal tiers or rows to the desired height of the fuel basket. At least some slotted plates comprise cantilevered lateral plate extensions on the ends which protrude perpendicularly beyond the flat lateral walls and exterior peripheral surfaces of the adjoining plate on the sides of the basket. The vertical edge surfaces of the ends of the plate extensions are configured to terminate proximate to or abut the interior surface of the cylindrical canister. This restricts lateral movement of the fuel basket within the fuel storage canister in the case of a seismic event or if dropped during handling such as insertion of the canister into a radiation shielded outer transfer or storage cask. A plurality of differently configured lateral peripheral pockets, spaces, or gaps is formed between the exterior walls of the fuel basket and canister shell. In one embodiment, vertically elongated reinforcement members are disposed in at least some of the gaps. The reinforcement members are fixedly coupled directly to the fuel basket, and more specifically in some constructions to the slotted plate extensions that define part of peripheral gaps in conjunction with the circular arcuate interior surfaces of the canister. The reinforcement members may have a height coextensive with the height of the fuel basket. In certain embodiments, the reinforcement members may comprise reinforcement plates or a combination of reinforcement plates and tubular shim members both of which are fixedly coupled directly to the cantilevered basket plate extensions. This provides structural reinforcement of the fuel basket plate extensions and in turn the overall fuel basket structure in both the lateral direction and vertical direction if subjected to compression forces in the event the basket were dropped on its end during insertion into the canister, or if the canister were similarly dropped after the basket is in place. The structural integrity of the fuel assemblies contained the fuel basket is therefore better protected overall. The bottom edges of some or all of the lateral plate extensions and reinforcement members may further comprise flow cutouts or holes where the edges abuttingly engage the bottom closure plate of the canister. This allows the inert gas (e.g. helium or other inert gas) which fills the hermetically sealed cavity of the canister and protectively blankets the fuel assemblies therein to recirculate up and down via natural convective thermosiphon action driven by the gravity and the heat emitted from the decaying fuel assemblies. The peripheral spaces or gaps between the fuel basket and cylindrical shell of the canister act as a gas flow downcomer of the gas recirculation circuit which is in fluid communication with the riser space formed inside the fuel basket through the nuclear fuel assemblies via the flow cutouts. According to one aspect, a nuclear fuel storage system comprises: a canister comprising a cylindrical shell extending along a vertical centerline; a fuel basket positioned in the canister, the fuel basket formed by a plurality of orthogonally arranged and interlocked slotted plates which collectively define exterior side surfaces of the fuel basket; the fuel basket comprising a plurality of interior cells being defined by the slotted plates, each interior cell configured to hold a fuel assembly comprising spent nuclear fuel; at least some of the slotted plates comprising cantilevered plate extensions, the plate extensions protruding laterally beyond the exterior side surfaces of the fuel basket and defining peripheral gaps between the fuel basket and the canister; wherein the plate extensions are configured to engage the shell of the canister. According to another aspect, a nuclear fuel storage system comprises: a canister comprising a cylindrical shell extending along a vertical centerline; a fuel basket positioned in the canister, the fuel basket defining a grid array of interior cells each of which is configured to hold a fuel assembly comprising spent nuclear fuel; the fuel basket comprising a plurality cantilevered plate extensions, the plate extensions protruding laterally beyond vertical exterior side surfaces of the fuel basket and defining peripheral gaps between the fuel basket and the canister; and a plurality of vertically elongated reinforcement members positioned in the peripheral gaps, the reinforcement members each being fixedly coupled to the plate extensions. According to another aspect, a method for forming a structurally reinforced fuel basket for storing nuclear fuel comprises: providing a fuel basket comprising a plurality of vertically stacked and interlocked slotted plates collectively defining a plurality of vertical exterior sidewalls, a plurality of lateral plate extensions protruding laterally outward beyond the exterior sidewalls, and a plurality of storage cells each of which is configured to hold a fuel assembly comprising spent nuclear fuel; fixedly coupling a plurality of vertically elongated reinforcement members to the plate extensions; and inserting the fuel basket with coupled reinforcement members into an upwardly cavity of a cylindrical nuclear fuel storage canister. In some embodiment, the fixedly coupling step includes bolting the reinforcement members to the lateral plate extensions. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. All drawings are schematic and not necessarily to scale. Features shown numbered in certain figures which may appear un-numbered in other figures are the same features unless noted otherwise herein. A general reference herein to a figure by a whole number which includes related figures sharing the same whole number but with different alphabetical suffixes shall be construed as a reference to all of those figures unless expressly noted otherwise. The features and benefits of the invention are illustrated and described herein by reference to non-limiting exemplary (“example”) embodiments. This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. Accordingly, the disclosure expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features. In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. As used throughout, any ranges disclosed herein are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, any references cited herein are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls. As used herein, the terms “seal weld or welding” if used herein shall be construed according to its conventional meaning in the art to be a continuous weld which forms a gas-tight joint between the parts joined by the weld. FIGS. 3-8 depict a nuclear fuel canister 100 with a first embodiment of a nuclear fuel basket 200 comprising of a hybrid integral shimming system according to the present disclosure for centering, supporting, and reinforcing the basket structure. The shimming system utilizes a plurality of reinforcement members including a combination of reinforcement plates 250 and tubular shim members 260 all fixedly coupled to the fuel basket as further described in detail below. This contrasts to the use of prior “loose” basket shims which are not affixed to the fuel basket and therefore do not structural reinforce the fuel basket outside of the canister. The present reinforcement members are positioned in some, but not necessarily all peripheral pockets or gaps G formed between the fuel basket and the canister. The reinforcement plates 250 may generally have a smaller more compact cross-sectional profile allowing them to be used in tighter/smaller peripheral gaps, whereas the tubular shim members 260 with larger cross-sectional profiles can be used in the larger gaps. Canister 100 may be used for storing any type of high level radioactive nuclear waste, including without limitation spent nuclear fuel (SNF) or other forms of radioactive waste materials removed form the reactor. The SNF canister 100 may be any commercially-available nuclear fuel/waste storage canister, such as a multi-purpose canister (MPC) available from Holtec International of Camden, N.J. or other. Canister 100 has a vertically elongated and metallic body a cylindrical shell 101 extending along a vertical centerline Vc which passes through the geometric center of the shell. Canister 100 includes a bottom closure plate 102 seal welded to a bottom end of the shell, and a top closure plate 103 seal welded to a top end of the shell. A hermetically sealed cavity 104 is therefore formed inside the canister such as via seal welding the closure plates to the shell ends. The foregoing canister parts may be formed of any suitable metal, such as for example without limitation steel including stainless steel for corrosion protection. Fuel basket 200 is a honeycomb prismatic structure which comprises a top 230, bottom 231, and plurality of stepped and rectilinear shaped peripheral sides 232 defining exterior sidewalls 232A extending vertically therebetween. The structure of the fuel basket 200 is formed by a plurality of the interlocked and orthogonally intersecting slotted plates 210. Slotted plates 210 are horizontally elongated in length each having a length (measure transversely to vertical centerline Vc) substantially greater than their height (e.g. at least 4 times the height or more). Peripheral sides 232 of the outermost exterior slotted plates 210 define outward facing exterior peripheral side surfaces 233 which are collectively formed by the slotted plates 202. Plates 210 may be continuous monolithic structures which extend diametrically/laterally from one side of the canister 100 to the opposite side as shown. The elongated slotted plates 210 each define a centerline longitudinal axis LA extending along the length of the plate. In one embodiment, slotted plates 210 each include flat and parallel opposing vertical major sides surfaces 211, 212, a top longitudinal edge 213, bottom longitudinal edge 214, and opposing ends 215 defining peripheral side edges 217 of the plates. To interlock the plates, a plurality of longitudinally spaced apart vertical slots 216 are formed perpendicularly to longitudinal axis LA in the top longitudinal edge, bottom longitudinal edge, or both of each (depending on the location of the plate in the fuel basket 200). The plates are oriented horizontally/laterally and interlocked with each other via the slots 216 to form a stacked structure comprised of multiple horizontal rows or tiers of plates rising and stacked to the desired height of the fuel basket. The fuel basket may be slightly shorter than the canister 100 in height such that an upper flow plenum 200A is formed between top 230 of the basket and the canister top closure plate 103 (see, e.g. FIGS. 13A-B), which is further described herein. The uppermost plates 210A from the top tier comprise only downwardly open slots 216, the lowermost plates 210C from the bottom tier comprise only upwardly bottom slots 216, and those intermediate plates 210B in middle tiers therebetween comprise both top and bottom slots 216. As shown, the slots 216 extend only partially through the entire height H1 of the slotted plates, approximately 50% or less of height H1 in some embodiments. The plates 210A-C may have the same or different heights and lengths depending on their location with the fuel basket structure. Fuel basket 200 includes a grid array of plural vertically-extending fuel assembly storage cells 240 in its interior. Each cell is configured in cross-sectional area and shape to hold a single U.S. style fuel assembly 28, which contains multitude of spent nuclear fuel rods 28a (or other nuclear waste). An exemplary fuel assembly of this type having a conventional rectilinear cross-sectional configuration is shown in FIG. 19. Such fuel assemblies are well known in the industry. The cells 240 of the fuel basket are defined by the orthogonally intersecting slotted plates 210, and therefore a concomitantly rectilinear cross-sectional shape (e.g. square). This gives the fuel basket an overall compound rectilinear polygonal shape in transverse cross section as shown which includes multi-faceted and stepped exterior peripheral side surfaces 233 collectively defined by the flat lateral peripheral sidewalls 232A of the outermost exterior slotted plates 210. A plurality of peripheral spaces or gaps G are formed around the perimeter of the fuel basket 200 between the peripheral sidewalls 232A and interior surface 110 of the fuel canister 100. The gaps G extend vertical for the full height of the fuel basket in the canister. As shown for example in FIG. 8 et al., the gaps G vary in size and configuration, but generally have the same compound arcuate shape on the outermost portion attributed to the cylindrical canister shell 101, and a rectilinear shape on the innermost portions attributed to the fuel basket geometry which collectively define the gaps. To laterally stabilize and center the fuel basket 200 in the canister 100, and compensate for the mismatch between the rectilinear polygonal exterior peripheral side surfaces 233 of fuel basket 200 and non-polygonal and circular arcuate interior surface 110 of canister 100, at least some of the slotted plates 200 comprise a cantilevered lateral plate extension 220 formed on one or preferably both ends. When the slotted plate are interlocked and assembled into the final fuel basket assembly, the lateral plate extensions 220 protrude perpendicularly and laterally outward beyond the flat outwardly facing exterior peripheral side surfaces 233 of the adjoining plate which is oriented perpendicularly to the extension (see, e.g. FIGS. 5B and 8). It bears noting that the vertical end surfaces of the plate extensions 220 define the plate ends 215 and concomitantly peripheral side edges 217 of the slotted plates 210 previously described herein. The peripheral side edges of the extensions are configured to terminate proximate to or abut the interior surface of the cylindrical shell 101 of canister 100. This ensures contact between the slotted plates and canister shell to stabilize the fuel basket 200 in the lateral direction during the occurrence of a seismic event which can shake the fuel canister 100 and nuclear fuel assemblies 28 therein. It bears noting that not all slotted plates 210 necessarily require plate extensions 220. It further bears particular noting that the peripheral side edges 217 defined by the plate extensions 220 of the present slotted plates 210 shown in FIG. 4 each form a straight vertical linear peripheral edge which extends for the full height H1 of the slotted plate 210 from top longitudinal edge 213 to bottom longitudinal edge 214. This contrasts to the undulating edge formed in conventional slotted plate designs which include a tab projection for insertion into a slot-shaped hole of a perpendicularly mating slotted plates (compare FIGS. 2A and 4). In such prior designs shown in FIG. 2A, the tabs do not extend beyond the perpendicularly mating plate as shown in any manner sufficient to form any structural extensions of the plate sufficient to attach and support any other elements in the peripheral gaps between the fuel basket and cylindrical canister shell. The present slotted plates 210 may have a monolithic body of unitary structure in one embodiment from end to end 215. Plates 210 may be formed of any suitable material. One non-limiting example is a metal, such as preferably a corrosion resistant metal like stainless steel. For enhanced radiation blocking, some or all of the slotted plates may alternatively be formed of suitable radiation shielding materials such as a boron-containing material like Metamic® (a proprietary product of Holtec International of Camden, N.J.). Metamic® is a discontinuously reinforced aluminum boron carbide metal matrix composite material designed for neutron radiation shielding. Other material may be used for plates 210 in certain embodiments. With continuing reference to FIGS. 3-8, the fuel basket 200 in another aspect further includes a plurality of vertically-extending and elongated reinforcement members or plates 250. Reinforcement plates 250 are positioned in at least some of the peripheral gaps G in the canister 100 between the exterior peripheral side surfaces 233 of the fuel basket 200 and interior surface 110 of the fuel canister 100. The plates 250 are preferably rigidly affixed and coupled to the fuel basket, such as without limitation slotted plate extensions 220 as shown. The reinforcement plates 250 provide structural support and reinforcement of the extensions and fuel basket 200 in both (1) the vertical direction under compression forces in the event the basket were dropped on its end during insertion into the canister 100 (or if the canister were dropped on its end with the fuel basket installed), and (2) the lateral direction. Because the plate extensions 220 are cantilevered without lateral support, they are more susceptible to bending and damage if impacted and not buttressed by the reinforcement plates depending on the unsupported length of the cantilever. The reinforcement plates 250 may be provided in coordinated pairs of plates of the same or different configurations in some embodiments. At least some of the slotted plate extensions 220, and a majority in certain instances may be fitted with mating pairs of reinforcement plates 250. In certain embodiments, a majority of slotted plate extensions 220 may be coupled to a pair of reinforcement plates 250 (see, e.g. FIGS. 14-18). One reinforcement plate 250 in each pair may be coupled to opposite major side surfaces 211, 212 of the slotted plate 210 on extensions 220 as shown in certain embodiments. These plate extensions 220 may therefore be sandwiched between pairs of reinforcement plates 250 which structurally reinforce the plate extensions from both sides. In certain embodiments of fuel baskets 200, a single reinforcement plate 250 may be fixedly coupled to one side of some of the plate extensions 220 at certain locations as needed around the peripherally of the basket. Such an arrangement is shown in FIGS. 5-8 further described below. The reinforcement plates 250 may extend vertically for the full height of the basket 200 from the top 230 to bottom 231 thereby having a coextensive height to the basket. Plates 250 may be formed of any suitable metal, such as preferably a corrosion resistant metal such as for example without limitation aluminum or stainless steel. Other metals may be used. Reinforcement plates 250 may have a variety of polygonal transverse cross-sectional shapes (e.g. rectilinear) as needed to match the configuration of the peripheral spaces or gaps G between the fuel basket 200 and cylindrical canister shell 101 where they plates are to be installed. The plates 250 may have typical structural shapes used in industry and are laterally open structures which do not define an interior space (unlike the tubular shimming members 260 further described herein). Non-limiting examples of some rectilinear shapes which may be used for reinforcement plates 250 include for example without limitation straight reinforcement plates 250A having a flat strap-like body and L-shaped angled reinforcement plates 250B having an angled body similar to a structural angle (see, e.g. FIG. 8). The angled reinforcement plates 250B may have perpendicularly oriented legs of equal or unequal width as needed to match the cross-sectional shape and geometry of the peripheral G in which the plates are to be positioned. Other polygonal shapes, non-polygonal shapes, or combinations thereof may be used for reinforcement plates 250 as needed to match the shape of the mating associated peripheral gap G in which the plates are to be positioned. Single or pairs of reinforcement plates 250 may be fixedly coupled to the lateral plate extensions 220 of slotted plates 210 via any suitable coupling mechanism. In one embodiment, reinforcement plates 250 may be bolted to the slotted plate extensions via bolts 251 which comprise assemblies of the elongated threaded bolt body, nuts, and washers as shown. The nuts may be tack welded to the bolt bodies after assembly to the fuel basket plate extensions 220 to prevent their loosening. The bolt bodies are received through bolt holes 265 formed in the plate extensions 220 and reinforcement plates 250 at the bolting locations. The reinforcement plates 250 are bolted to at least the plate extensions 220 of the uppermost and lowermost slotted plates 210 in the fuel basket assembly. Multiple bolts may be used at these upper and lower locations to fixedly couple the reinforcement plate 250 to the slotted plate extensions 220 as shown. Preferably, the reinforcement plates may be further bolted to some intermediate plate extensions 220 therebetween along the height of the fuel basket 220 in a vertically spaced apart manner for added securement of the extensions to the fuel basket 200 (see, e.g. FIG. 5A). The bolting may be completed to rigidly affix the reinforcement plates 250 to the fuel basket 200 before the basket 200 is slideably inserted into the cavity 104 of the fuel canister 100. It will be appreciated that the reinforcement plates 250 are only positioned within the peripheral pockets or gaps G outboard of the peripheral sides 232 of the fuel basket 200 around its perimeter, and not the interior. Because the bolting preferably does not protrude into any of the fuel assembly storage cells 240 of the basket 200, the bolts 251 do not interfere with sliding and loading the spent fuel assemblies 28 into the cells. Reinforcement plates 250 may be formed of a suitable metal such as high temperature tolerant materials like Aluminum Alloy 2219 or other, corrosion resistant steel such as stainless steel, or other metal which may be extruded or otherwise formed to shape. With continuing reference to FIGS. 3-8, the hybrid shimming system of fuel basket 200 further includes reinforcement members in the form of tubular shim members 260 fixedly coupled to the basket (e.g. plate extensions 220). Shim members 260 may occupy peripheral gaps G which do not contain reinforcement plates 250 in some embodiments. This provides several advantages. For example, the tubular shim members may be positioned into larger peripheral gaps G around the perimeter of the fuel basket to add greater structural stability and reinforcement of the basket in those locations. The smaller peripheral gaps may be structurally reinforced by use of the reinforcement plates 250 in those locations which can be fabricated and are shaped to fit such tighter spaces more readily. By integrating the tubular shim members 260 into the basket structure by rigid fixation thereto, a greater resistance of the fuel basket to compressive forces acting on the ends of the shim members and basket is achieved since the shim tubes act as columns which structurally can withstand greater compressive forces if the canister (or fuel basket alone before insertion therein) were dropped during handling than the reinforcement plates 250 alone. The tubular shim members 260 also offer greater resistance to laterally directed forces on the fuel basket and canister in the event of a drop at least partially on the side of the basket or canister after basket insertion therein. This advantageously offers better protection for the fuel assemblies in the basket from physical damage during a drop event. In addition, fabrication costs can be reduced for the fuel basket 200 since the number of tubular shim members 260 can be minimized when combined with the reinforcement plates 250 which generally have simpler rectilinear shapes (in cross section) as shown that are less costly to fabricate. The tubular shim members 260 each comprise vertically elongated bodies defining a top end 261, bottom end 262, and sidewalls 263 extending therebetween which defines an enclosed central opening 264. Top and bottom ends 261, 262 may be open to the central opening 264. Tubular shim members 260 may have a height coextensive with the height of the fuel basket, and further with the height of the reinforcement plates 250. Both the tubular shim members 260 and reinforcement plates 250 are oriented parallel to the vertical centerline Cv of the canister 100. Tubular shim members 260 may have a variety of transverse cross-sectional shapes as need to complement the geometry of the peripheral gaps G in which they are positioned. Shim members 260 may therefore have a polygonal cross-sectional shape (e.g. rectangular, square, triangular, hexagonal, etc.), non-polygonal cross-sectional shape (e.g. circular, etc.), or combinations thereof. In the illustrated embodiment, a combination of rectilinear tubular shim member 260A comprised of four substantially straight rectangular walls, and partial square shim members 260B comprised of three perpendicularly oriented inner straight walls, and an outer arcuately curved wall extending therebetween are provided. Other shapes may be used depending on the cross-sectional shape of the peripheral gap G. For example, the embodiment of FIGS. 9-12 further described herein show tubular shim members 260C having a partial triangular cross-sectional shape comprising two perpendicularly oriented inner walls and an outer arcuately curved wall extending therebetween which matches the curve of the canister 100 interior surface. Similarly to reinforcement plates 250, tubular shim members 260 may be fixedly coupled to the slotted plate extensions 220 of fuel basket 200 in the same manner such as in one embodiment via bolts 251 previously described herein which comprise assemblies of the threaded bolt body, nuts, and washers. The shim members 260 are bolted to at least the plate extensions 220 of the uppermost and lowermost slotted plates 210 in the fuel basket assembly. The vertical central space 264 and open top and bottom ends 261, 262 of the tubes provide access to the bolting necessary to tighten the fastener assemblies. Accordingly, part of the bolts 251 protrudes into the central spaces of the tubes as shown. Multiple bolts may be used at these upper and lower locations to fixedly couple the reinforcement plate 250 to the slotted plate extensions 220. In some embodiments as shown, the same bolts 251 may be used to fixedly couple both a reinforcement plate 250 and a tubular shim member 260 to a single slotted plate extension 220. The plate extension may therefore be sandwiched in an assemblage between the reinforcement plate and shim tube (best shown in FIG. 8). In some instances, a pair of tubular shim members 260 may occupy the same peripheral pocket or gap G (see, e.g. FIG. 8, top right detail image). In other less preferred but still satisfactory embodiments, the tubular shim members 260 and/or reinforcement plates 250 may be welded to the slotted plate extensions 220. Bolting shim members 260 and reinforcement plates 250 to the fuel basket plate extensions 220 obviates any issues with forming dissimilar metal welds and offers fabrication savings since bolting is generally a less expensive coupling procedure than welding. Tubular shim members 260 may be formed of a suitable metal such as high temperature tolerant materials like Aluminum Alloy 2219 or other, corrosion resistant steel such as stainless steel, or other metal which may be extruded or otherwise formed to shape. With continuing reference to FIGS. 4-8, the bottom edges of some or all of the lateral plate extensions 220, reinforcement plates 250, and/or tubular shim members 260 may further comprise flow holes or cutouts 270 where the edges abuttingly engage the bottom closure plate 102 of the canister 100. This provides flow access to the fuel assembly storage cells 240 in the basket 200 which allows the inert gas (e.g. helium or other inert gas) circulating and contained in cavity 104 of the canister to blanket the fuel assembles for corrosion protection. The flow cutouts 270 allow the gas to recirculate up and down within the canister via natural convective thermosiphon action driven by the heat emitted from the decaying fuel assemblies 28. The peripheral spaces or gaps G between the fuel basket and cylindrical shell 101 of the canister 100 act as a gas flow downcomer of the gas recirculation circuit which is in fluid communication via cutouts 270 with the interior space formed by the cells 240 inside the fuel basket which contain the fuel assemblies. The upper flow plenum 200A formed in the canister above the top of the fuel basket 200 is in fluid communication with both the peripheral downcomer and interior riser. This is best shown in FIG. 13B which depicts inert gas flow arrows showing the gas flow recirculation circuit used to cool the fuel assembly. FIGS. 9-13B depict a nuclear fuel canister 100 with fuel basket 200 comprising a second embodiment of a hybrid integral shimming system according to the present disclosure which structurally reinforces and centers/stabilizes the fuel basket 200 in the canister. This embodiment is similar to the first embodiment shown in FIGS. 3-8 in that it combines reinforcement members comprising both reinforcement plates 250 and tubular shim members 260; albeit some of slightly different configuration. These reinforcement members are fixedly bolted to the fuel basket cantilevered lateral plate extensions 220 and have a vertical height coextensive with the full height of the fuel basket. These reinforcement members may include flow cutouts 270 (also formed in the slotted plate extensions 220 as previously described herein. All similar features of the canister, fuel basket, and shimming system will therefore not be repeated here in detail for the sake of brevity. Differences will be described with a general overview of the second embodiment as well. Although the present embodiment (and the prior embodiment in FIGS. 5-8) uses a combination of reinforcement members comprised of both reinforcement plates 250 and tubular shim members 260, it bears noting that in other embodiments only reinforcement plates or only tubular shim members may be used depending on the configuration/geometry and sizes of the peripheral gaps G formed between the canister shell 101 and exterior sidewalls 232A of the fuel basket. Referring to FIGS. 9-13B, fuel basket 200 comprises more interior fuel assembly storage cells 240 (e.g. 44 cells as shown) than the number of cells in the embodiment of the fuel basket of FIGS. 3-8 (e.g. 37 cells as shown). The diameter of the canister 100 however may be same in both embodiments in certain instances. The 37 cell fuel basket represents the largest capacity previously available on the market, which is limited at least in part by the lower heat rejection capacity of prior basket designs which dissipates heat emitted by the decaying nuclear fuel assembly. Accordingly, the greater heat rejection capability of the present fuel basket designs using the integral shimming system advantageously allows for a greater number of fuel assemblies to be safely stored in the canister without increasing the diameter. The reinforcement members in the present embodiment of FIGS. 9-13B include perpendicularly angled reinforcement plates 250B previously described herein. In this embodiment of the fuel basket shimming system, angled plates 250B have legs of unequal length to fit the peripheral gap G in which they are located. The tubular shim members include the four sided shim members 260B and generally triangular shaped shim members 260C previously referred to. In this embodiment, shim members 260B and 260C are fixedly coupled together via bolts 251 which pass laterally/horizontal therethrough and through lateral plate extensions 220 of the fuel basket which is sandwiched between the shim members and extension as shown. The shim members 260B and 260C occupy different peripheral gaps G on each side of the plate extension. FIGS. 14-18 depict a nuclear fuel canister 100 with fuel basket 200 comprising a third embodiment of a hybrid integral shimming system according to the present disclosure which structurally reinforces and centers/stabilizes the fuel basket 200 in the canister. Fuel basket 200 in this embodiment comprises more interior fuel assembly storage cells 240 (e.g. 104 cells as shown) than the number of cells in either the fuel baskets of FIG. 3-8 or 9-13B. The canister diameter however may be the same as in these prior embodiments described. The increased number of storage cells 240 results in peripheral gaps G generally too small to practically accommodate tubular shimming members 260 having larger transverse cross-sectional profile. This embodiment includes reinforcement members comprising only reinforcement plates 250A of the straight and flat strap-shaped design previously described herein. In some peripheral gaps G, a pair of perpendicularly oriented reinforcement plates 250A may be positioned in a single gap and fixedly coupled to different orthogonally oriented plate extensions 220 as shown to collectively form an L-shaped angled support. These 2-piece assemblies of reinforcement plates 250A may be replaced in some embodiments by a single monolithic angled reinforcement plate 250B previously described herein. The reinforcement plates are fixedly bolted to the fuel basket cantilevered lateral plate extensions 220 by bolts 251 and have a vertical height coextensive with the full height of the fuel basket. These reinforcement members may also include flow cutouts 270 as needed (also formed in the slotted plate extensions 220 as previously described herein). All other similar features of the canister, fuel basket, and present shimming system as the prior shimming system embodiments described will therefore again not be repeated here in detail for the sake of brevity. A method for forming a structurally reinforced fuel basket for storing nuclear fuel will now be briefly described. The steps of the method may include interlocking a plurality of slotted plates 210 to form a fuel basket comprising a plurality of vertical exterior sidewalls 232A and a rectilinear grid array of a plurality of fuel assembly storage cells 240. The interlocked slotted plates 210 are configured such that the cantilevered lateral extensions 220 are formed which protrude outwards beyond the sidewalls 232A along the entire height of the fuel basket. With the fuel basket 200 thus provided, the method continues with fixedly coupling a plurality of the vertically elongated reinforcement members directly to the lateral plate extensions 220 of the fuel basket. The reinforcement members may include reinforcement plates 250 and/or tubular shimming members 260. In one embodiment, the plates and shimming members are bolted to the lateral plate extensions 220 using bolts 250 previously described herein and extend for the full height of the fuel basket 200. The method may further include forming a gas flow path between the peripheral gaps G at the bottom of the fuel basket 200 and the interior fuel storage cells 240 by providing the flow cutouts 270 in the bottom end of some or all of the reinforcement plates 250 if used, tubular shimming members 260 if used, and the lateral plate extensions 220 of the lowermost tier of slotted plates 210 abutting the bottom closure plate 102. The reinforcement members structurally reinforce the fuel basket to protect the integrity of the fuel storage cells and fuel assemblies to be stored therein as previously described. The reinforced fuel basket 200 is next inserted and slid through the open top end of the canister 100 into the cavity 104. The bottom closure lid 102 has already been hermetically seal welded onto the bottom end of the canister previously. The fuel basket becomes seated on the upward facing top surface of the bottom closure lid. One or more fuel assemblies 28 are then inserted into the storage cells 240 of the basket. The top closure lid 103 is then hermetically seal welded onto the top end of the canister 100 which completes the encapsulation of the fuel basket and fuel assembly (see, e.g. FIGS. 13A-B. The canister 100 may then be filled with an inert gas (e.g. helium, nitrogen, etc.) which begins to flow in the gas recirculation circuit within the canister driven by the natural convective thermo-siphon as the gas is heated by the fuel assemblies 28. Numerous advantages can be realized with the present fuel basket integral shimming system embodiments disclosed herein, which can be summarized as including but not limited to the following. The bottom edges of the slotted plates 210, lateral plate extensions 220, reinforcement plates 250 if provided, and tubular shim members 260 if provided may include flow cutouts 270 as previously described herein to enable inert gas (e.g. helium or other) recirculation by the natural gravity-driven thermosiphon action. It bears particular note that not all of these components require flow cutouts depending on their location and orientation within the fuel canister 100 in relation to the peripheral gaps G which collectively form the downcomer of the inert gas recirculation system within the canister. The cross sectional area of the open peripheral spaces or gaps G around the perimeter of the fuel basket 200, which serve as the downcomer for the recirculating gas, is maximized by limited use of tubular shims fixedly attached to the slotted plate extensions 220 which helps boost the convective heat transfer to the canister shell wall and cooling of the fuel assemblies in the basket. Each slotted plate extension 220 serves as a heat transfer extended surface (“fin”) projecting laterally outwards from the prismatic fuel basket 200 to enhance dissipation of heat emitted by the fuel assemblies in the basket to the peripheral gaps and in turn to the canister shell 101. These heat transfer fins or extended surfaces aid in helping to draw the waste heat from the interior of the basket and transferring the heat to the recirculating inert gas flowing downwards through in the downcomer space defined by the peripheral gaps G internal to the canister 100. The flow holes or cutouts 270 provide a direct line of sight between the bottom of the stored fuel and the bottom region of the fuel storage canister shell 100 which helps maximize radiative heating of the bottom region of the canister fuel confinement boundary and thus alleviate the risk of stress corrosion cracking of the canister which can occur under the right environmental conditions; a well known phenomenon and failure mechanism in the art. The need to weld the exterior peripheral basket slotted panels or plates 210 together is eliminated by bolting the reinforcement members (e.g. reinforcement plates 250 and/or tubular shimming members 260) to the fuel basket lateral plate extensions 220, thereby enabling the assembled basket to be entirely weld-free and thus of high dimensional fidelity. This significantly reduces fabrication times and costs. The reinforcement members structurally ties the upper and lowest slotted plates 210 together to lock the entire vertical stack of plates into a structurally stable assemblage. The reinforcement plates 250 and tubular shim members 260, which extend all the down to the bottom edge of the fuel basket 200, help to strengthen and stiffen the basket against axial inertial loads during any postulated vertical drop event as well as against any related laterally-acting inertial radial loads (if basket dropped partially on its side). During such a vertical drop event, the axial impact forces are transmitted between the bottom closure lid of the canister 100 to the opposite end top closure lid via the vertically-extending reinforcement plates and shim members. While the foregoing description and drawings represent some example systems, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope and range of equivalents of the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. In addition, numerous variations in the methods/processes described herein may be made. One skilled in the art will further appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims and equivalents thereof, and not limited to the foregoing description or embodiments. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention. |
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summary | ||
claims | 1. A reactor for containing a nuclear reaction, the reactor comprising:a sealable containment envelope having an inner surface, the containment envelope having a pressure limit of a gas contained within the containment envelope;a vessel including core material and located within the containment envelope, the vessel designed to enclose the core material at temperatures below a breach temperature;the inner surface having a containment temperature below the breach temperature; andan apparatus comprising a first material disposed in a location within the containment envelope such that upon a breach of the vessel by the core material, the breached core material contacts the first material; the first material having:a melting point below the breach temperature;a boiling point above the containment temperature; anda difference between the melting point and boiling point that is greater than 100 degrees Celsius. 2. The reactor of claim 1, wherein the first material has a boiling point above 100 degrees Celsius at a pressure of 1 atmosphere. 3. The reactor of claim 1, wherein the breach temperature is above 500 degrees Celsius and the boiling point is below the breach temperature. 4. The reactor of claim 1, wherein the first material has a melting point between 50 and 800 degrees Celsius. 5. The reactor of claim 1, wherein the first material has a boiling point at 1 atmosphere between 150 and 3000 degrees Celsius. 6. The reactor of claim 1, wherein the first material has a melting point between 200 and 700 degrees Celsius, and a boiling point between 800 and 2650 degrees Celsius. 7. The reactor of claim 1, wherein the melting point is greater than the containment temperature. 8. The reactor of claim 1, wherein the first material comprises a composition that is not expected to exothermically react with any component comprising more than 1% of the breached core material at the breach temperature and the pressure limit. 9. The reactor of claim 1, wherein the boiling point of the first material is above a third temperature between the breach and containment temperatures, and the third temperature is within 400 degrees Celsius of the containment temperature. 10. The reactor of claim 9, wherein the melting point of the first material is below the third temperature. 11. The reactor of claim 1, wherein the difference between the melting point and the boiling point is greater than 100 degrees Celsius and less than 2700 degrees Celsius. 12. The reactor of claim 1, wherein a liquid phase of the first material has a density greater than a density of at least 10% of core material. 13. The reactor of claim 1, further comprising a system to contain the breached core material and a liquid phase associated with the first material, wherein the system includes a depth sufficient to float the breached core material above a bottom surface of the containment envelope, and the first material has at least the volume necessary to float the breached core material above the bottom surface. 14. The reactor of claim 1, further comprising a system to contain the breached core material and a liquid phase associated with the first material, wherein upon contact between the breached core material and the first material, the first material forms a liquid puddle having a depth and a width, and the depth is less than 20% of the width. 15. The reactor of claim 1, wherein the first material comprises any of Pb, Zn, Sn, S, and Bi. 16. The reactor of claim 1, wherein the first material comprises Al. 17. The reactor of claim 1, further comprising an apparatus associated with the inner surface configured to increase the condensation rate. 18. The reactor of claim 1, wherein the inner surface is in fluid communication with the first material. 19. The reactor of claim 1, wherein the first material has a melting point below 700 degrees Celsius. 20. A method of transferring heat from a core material inside a containment envelope to a region outside the containment envelope, the method comprising providing a reactor having:a sealable containment envelope having an inner surface, the containment envelope having a pressure limit of a gas contained within the containment envelope, the containment envelope in thermal communication with the region outside the containment envelope;a vessel including the core material and located within the containment envelope, the vessel designed to enclose the core material at temperatures below a breach temperature;the inner surface having a containment temperature below the breach temperature; andan apparatus comprising a first material disposed in a location within the containment envelope such that upon a breach of the vessel by the core material, the breached core material contacts the first material; the first material having:a melting point below the breach temperature;a boiling point above the containment temperature; anda difference between the melting point and boiling point that is greater than 100 degrees Celsius at a pressure of 1 atmosphere;operating the reactor; andallowing core material at a temperature above the breach temperature to contact the first material. |
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description | This application is a continuation-in-part of U.S. patent application Ser. No. 11/231,227, filed on Sep. 20, 2005, now issued as U.S. Pat. No. 7,470,921 on Dec. 30, 2008 entitled ULTRAVIOLET LIGHT-EMITTING DIODE DEVICE, the disclosure of which is hereby expressly incorporated herein by reference. 1. Field of the Disclosure The present disclosure relates to light-emitting diode devices and, more particularly, to ultraviolet light-emitting diode devices for use in curing fluids. 2. Description of the Related Art In methods for ultraviolet (UV) curing of fluids including inks, coatings, and adhesives, the cured substance includes UV photo initiators therein which, when exposed to UV light, convert monomers in the fluids into linking polymers to solidify the monomer material. Conventional methods for UV curing employ UV light-emitting diodes (LEDs) and UV lamps to supply UV light for curing UV curable fluids on various products. However, these methods are often time-consuming and inefficient, thereby increasing difficulty and expense for curing UV curable fluids. For example, known UV LED fluid-curing devices require a large number of light emitting sources which not only add size and cost to a fluid-curing device, but also are inefficient in terms of power usage. What is needed is an ultraviolet light-emitting diode device which is an improvement over the foregoing. The present disclosure relates to light-emitting diode devices. More particularly, the present disclosure relates to an ultraviolet (UV) light-emitting diode (LED) device for curing fluids such as inks, coatings, and adhesives, for example. In one embodiment, LEDs are positioned on faces defined by an inverted recess in a base portion. The LEDs are configured such that the light beams emitted from the LEDs converge at a single area or point to provide a single, focused area or point of amplified power from the LEDs. In another embodiment, the base portion is elongated to provide a single, focused line or region of amplified power from the LEDs. In one embodiment, the curing process occurs in an inert atmosphere. Because of the reduced number of light emitting sources required by the present disclosure, the size and cost of the UV LED device may advantageously be decreased. In one embodiment, a printed circuit is disposed in the base portion to provide power to the LEDs. All of the embodiments of the present disclosure advantageously reduce the amount of time required for curing the fluid and increase the efficiency of the curing process. In another embodiment, an optical culmination device is used to further intensify the power output from the LEDs. The optical culmination device provides enhanced power output from the UV LED device which makes the curing process more efficient than previous curing systems. In one form thereof, the present disclosure provides a system for curing a quantity of curable material, including a dispenser in communication with the quantity of curable material, the dispenser capable of dispensing a dispensed portion of the curable material; at least one light-emitting diode; and at least one optical culmination device positioned to intercept a light emitted from the at least one light-emitting diode and at least one of intensify and direct the light emitted from the at least one light-emitting diode to cure the dispensed portion of the curable material. In another form thereof, the present disclosure provides a system for curing a quantity of curable material, including a dispenser in communication with the quantity of curable material, the dispenser capable of dispensing a dispensed portion of the curable material; at least one light-emitting diode; and culmination means for at least one of intensifying and directing a light emitted from the at least one light-emitting diode to cure the dispensed portion of the curable material. In yet another form thereof, the present disclosure provides a system for curing a quantity of curable material, including a dispenser in communication with the quantity of curable material, the dispenser capable of dispensing a dispensed portion of the curable material; at least one light-emitting diode; and a base portion including a recess defining a plurality of faces, at least one light-emitting diode positioned on at least one of the faces, the faces configured to focus a light emitted from each at least one light-emitting diode to cure the dispensed portion of the curable material. Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. The exemplifications set out herein illustrate embodiments of the disclosure, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. Referring to FIGS. 1 and 11, LED device base 22 is shown including bottom edge 25 and recess 23 including faces 32, 35, 38, 41, and 44. First face 32 is formed as a square-shaped face and each second face 35, 38, 41, and 44 is formed as a trapezoid-shaped face. In this way, recess 23 forms an inverted, pyramidal frustum-shaped recess comprised of four congruent trapezoidal-shaped faces 35, 38, 41, 44, and square face 32. Square or first face 32 may be the center face and trapezoidal or second faces 35, 38, 41, and 44 may be the angled faces of LED device 20. Base 22 may be formed of various materials, and, in one embodiment, base 22 is an aluminum block with recess 23 machined therein. Base 22 may be constructed of any heat-dissipating and thermally-conductive material, for example, aluminum, copper, brass, a thermally conductive polymer, cobalt, or a combination of any of the previous, e.g., aluminum combined with a thermally conductive polymer. Recess 23 may be formed through extrusion, milling, or injection-molding processes. Although edge 25 is defined as bottom edge 25, it is to be understood that the bottom side of LED device 20 is the side normally facing a substance to be cured. The bottom side of LED device 20 may be oriented in any configuration including facing sideways, upwards, or any angle therebetween depending on the orientation of the substrate upon which a curable substance is deposited. Referring now to FIGS. 1 and 10, base 22 may be integrally formed with heat sink 52 having heat sink fins 53 extending away from base 22. Thus, heat sink 52 and heat sink fins 53 are made of identical or substantially similar material as base 22. Alternatively, device 20 may not include heat sink 52 and instead be cooled with such methods as convection, liquid cooling, or gas cooling of device 20. Referring now to FIGS. 1-3, LED device 20 includes base 22 with each face 32, 35, 38, 41, and 44 having LED 50 attached thereto. In one embodiment, LEDs 50 are centered on each respective face of base 22. In another embodiment, only some of faces 32, 35, 38, 41, and 44 have an LED 50 attached thereto. LEDs 50 are shown as relatively large, single point light sources, however, LEDs 50 may also be constructed of a plurality of point light sources (FIG. 6). Printed circuit 24 connects all five LEDs 50 and is connected to wires 30 which extend from base 22 to a power source (not shown) to provide power to LEDs 50. As shown in FIG. 3, wires 30 may be routed between heat sink fins 53 and then away from device 20 to connect to the power source. Printed circuit 24 may be formed directly in the material comprising base 22. LEDs 50 may be electrically interconnected via printed circuit 24 by any known interconnection method. In one embodiment, LEDs 50 may be UV LEDs to provide UV light for curing UV curable substances. UV LEDs 50 may be used to cure substances which include UV photo initiators contained therein which, when exposed to UV light, convert monomers in the substance into linking polymers to solidify the monomer material. In an alternative embodiment, LEDs 50 may include other types of LEDs such as visible light LEDs. In one exemplary embodiment, each LED 50 is a Part No. NCCU001 light-emitting diode, available from Nichia Corporation located in Japan. As shown in FIG. 3, structure 64 may be used to provide an inert atmosphere in which to cure the fluids. The inert atmosphere advantageously removes oxygen from the curing area. During the curing process, the photo initiators in the curable fluid will take an oxygen atom from other chemicals in the fluid in order to solidify the monomer material. If the curing process takes place in an atmosphere which contains oxygen, the curing process is slowed because the photo initiators take oxygen atoms from the surrounding atmosphere instead of the fluid chemicals. If oxygen is removed from the curing area, the photo initiators must latch on to oxygen atoms in the fluids instead of oxygen atoms from the surrounding area, thereby increasing the speed of the curing process. Structure 64 includes a plurality of apertures 63 disposed on bottom surface 67 thereof. Nitrogen or another inert gas may be supplied to hose 59 and enter structure 64 via hose connection 61. The gas circulates throughout the hollow interior of structure 64 and exits via apertures 63 to essentially provide a curtain of inert gas. The curing process will then take place inside this curtained inert atmosphere. In one embodiment, the inert gas may be provided via a nitrogen source (not shown) connected to hose 59 to supply nitrogen gas to structure 64. The nitrogen source may be a nitrogen tank or a nitrogen generator which essentially removes nitrogen from ambient air and pumps nitrogen gas into hose 59 for delivery to structure 64. Referring now to FIGS. 4 and 5, in one embodiment, faces 35 and 38 (FIG. 4) and faces 41 and 44 (FIG. 5) are angled such that light emitted from LED 50 on each respective face of base 22 converges at the same area or point, i.e., amplified area 48 or Point A. Faces 35, 38, 41, and 44 are all identically disposed at an angle θ with respect to a plane containing face 32. In one embodiment, angle θ is between 35° and 45°. In an alternative embodiment, angle θ is 36.7°. Various other measurements for angle θ may be chosen depending on the distance from device 20 to the substance to be cured. Additionally, the measurement of angle θ may vary depending on the dimensions of base 22, for example, if base 22 is widened, the measurements for angle θ would necessarily change to sustain the focused area or point of amplified power supplied by LEDs 50. Thus, angle θ could possibly measure anywhere between 0° and 90°. As shown in FIG. 4, LED 50 on face 38 emits light beam 39, LED 50 on face 32 emits light beam 33, and LED 50 on face 35 emits light beam 36. Light beam 36, light beam 33, and light beam 39 intersect one another and produce amplified area 48 of focused and amplified light wherein light from all three beams 33, 36, and 39 converge. Amplified area 48 may be a single point of amplified and focused light or amplified area 48 may be a small localized area which is positioned on a surface of substrate 68 (FIG. 12) upon which ink or another UV-curable fluid is deposited. As shown in FIG. 5, LED 50 on face 41 emits light beam 42 and LED 50 on face 44 emits light beam 45 which intersect and converge with light beams 33, 36, and 39 to further add amplification and power to amplified area 48. Therefore, light emitted from all five LEDs 50 disposed on faces 32, 35, 38, 41, and 44 converge at amplified area 48 to provide a single, focused, and amplified area of power from LEDs 50, thereby advantageously providing a significantly increased power source at a single area or location. As shown in FIGS. 4 and 5, each light beam emitted from LEDs 50 is in the general shape of a cone. The most intense light emitted from each LED 50 travels along a beam center line located in the exact center of the light cone, i.e., beam center lines 34, 37, 40, 43, and 46 for light beams 33, 36, 39, 42, and 45, respectively. The intensity of the light decreases moving away from the center of the beam towards the edge of the cone. As such, each beam center line meets at Point A which is the most focused and intense point of amplified light emitted from LEDs 50. The focused power from LEDs 50 may be arranged to provide a focused curing of a substance by positioning area 48 or Point A on the surface of a substrate containing a UV curable fluid. The focused area or point of amplified light reduces the likelihood of incomplete curing and increases the efficiency of the curing process because fewer LEDs need be employed. In one embodiment, Point A may be within amplified area 48. Referring now to FIG. 7, device 20 is shown including heat sink 52 having heat sink fins 53 and structure 64 attached on a bottom side thereof. Axial fan 66 may be mounted on top of heat sink fins 53 to further facilitate removal of heat from base 22 generated by LEDs 50. Axial fan 66 may include motor 71 to drive blades 69. Referring now to FIG. 12, a typical inkjet printer is shown including print head 60 which is capable of depositing fluid onto substrate 68. Print head 60 laterally moves along rail 62 in the directions defined by double-ended Arrow A. Device 20 is mounted on each side of print head 60 with heat sink 52 extending towards and connected to axial fan 66. Housings or structures 72 may also be provided to surround bases 22 of devices 20 and may be similar to structure 64 (FIGS. 3 and 7) described above. Tubes 65 may provide an inert gas, e.g., nitrogen, to housings 72, similar to hose 59 (FIG. 3) described above. The nitrogen gas in housings 72 may be used to create an inert gas curtain in which to cure the fluid deposited on substrate 68. For example, in one embodiment, the nitrogen gas may be released toward substrate 68 via a plurality of apertures 63 in the bottoms of housings 72 near substrate 68, similar to apertures 63 in structure 64 (FIG. 3) described above. Substrate 68 is supported by support structure 70 which may include a conveyor belt or other moving means capable of supporting and moving substrate 68. In operation and as shown in FIG. 12, LED 50 on face 35 of base 22 emits light beam 36 towards substrate 68, LED 50 on face 32 emits light beam 33 towards substrate 68, and LED 50 on face 38 emits light beam 39 towards substrate 68. Light beam 36, light beam 33, and light beam 39 intersect one another and produce amplified area 48 of light on substrate 68 wherein light from all three beams 33, 36, and 39 converge. In an exemplary embodiment, amplified area 48 is positioned on a surface of substrate 68 upon which fluid is deposited by print head 60. As shown in FIG. 5 but not shown in FIG. 12, LED 50 on face 41 and LED 50 on face 44 also produce light beams 42 and 45, respectively, which converge with beams 33, 36, and 39 to add to amplified area 48 of focused and amplified light power. Referring now to FIG. 6, an alternative embodiment LED device 20′ is shown including faces 32′, 35′, 38′, 41′, and 44′. In one embodiment, each second or angled face 35′, 38′, 41′, and 44′ may include a substantially identical angled configuration with respect to a plane containing first or center face 32′ as described above for faces 35, 38, 41, and 44 with respect to a plane containing face 32 (FIGS. 4 and 5). Faces 41′ and 44′ may, in one embodiment, be substantially similar in size and shape to faces 41 and 44, as described above, e.g., the parallel sides of faces 41′ and 44′ are substantially the same length as the parallel sides of faces 41 and 44. Faces 35′ and 38′, however, are not substantially congruent to faces 41′ and 44′. Instead, faces 35′ and 38′ are extended along a length of device 20′ and their parallel sides are of greater length than the corresponding parallel sides of faces 35 and 38. Faces 35′ and 38′ have a plurality of LEDs 50 positioned thereon in a straight line arrangement. Similarly, face 32′ is extended along the length of device 20′ and may be shaped as a rectangle with a plurality of LEDs 50 positioned thereon in a straight line arrangement. Faces 41′ and 44′ each also include LED 50 mounted thereon. Printed circuit 24′ connects all LEDs 50 mounted on device 20′ to a power source (not shown). Light emitted from LEDs 50 on faces 32′, 35′, 38′, 41′, and 44′ is directed in the same general direction as light emitted from LEDs 50 on faces 32, 35, 38, 41, and 44, as described above (FIGS. 4 and 5). The light emitted from LEDs 50 on faces 35′ and 38′ is substantially similar to light emitted from faces 35 and 38, as shown in FIG. 4. The primary difference as compared to device 20 is that device 20′ has the ability to provide a line or extended region of focused and amplified power centered over face 32′ as opposed to a single point or area of focused and amplified power as provided by device 20. In an alternative embodiment, only some of faces 32′, 35′, 38′, 41′, and 44′ have an LED 50 attached thereto. Referring now to FIGS. 8 and 9, an alternative embodiment device 20″ is shown including base 22″ having bottom edge 25″ and recess 23″ with faces 32″, 35″, 38″, 41″, and 44″. Heat sink 52″ is disposed on top 26″ of base 22″ and, in one embodiment, heat sink 52″ is integrally formed with base 22″. In one embodiment, base 22″ may include projection 56 and recess 58 to facilitate interconnection between adjacent bases 22″ wherein projection 56 of one base 22″ is shaped to mate with recess 58 of another base 22″. All faces 32″, 35″, 38″, 41″, and 44″ extend along longitudinal length L of base 22″. Although not shown, LEDs 50 may be disposed along faces 32″, 35″, 38″, 41″, and 44″ in a straight line arrangement on each respective face. In one embodiment, light emitted from LED 50 on each respective face converges along a line centered over center or first face 32″, similar to device 20′, as described above. In one embodiment, each base 22″ may have length L which measures approximately 5 inches. As shown in FIG. 8, angled or second faces 35″ and 38″ are disposed at first angle α with respect to a plane containing face 32″. In one embodiment, first angle α is between 25° and 30°. In an alternative embodiment, first angle α is 26.9902°. As shown in FIG. 8, angled or third faces 41″ and 44″ are disposed at second angle β with respect to a plane containing face 32″. In one embodiment, second angle β is between 50° and 60°. In an alternative embodiment, second angle β is 53.9839°. Various other measurements for angle α and angle β may be chosen depending on the distance from device 20″ to the substance to be cured. Additionally, the measurements of angle α and angle β may vary depending on the dimensions of base 22″, for example, if base 22″ is widened, the measurements for angle α and angle β would necessarily change to sustain the focused area of amplified power supplied by LEDs 50. Thus, angle α and angle β could possibly measure anywhere between 0° and 90°. In an alternative embodiment, more than one device 20″ may be employed in an end-to-end manner such as to lengthen the area of amplified power provided by LEDs 50 on device 20″ and provide a modularized system. In such an embodiment, more than one power supply may need to be employed for each device 20″, or, alternatively, a modified power supply could supply power to every device 20″ in the arrangement. If more than one device 20″ is employed, an inert atmosphere chamber (not shown) may be employed instead of the curtain-type inert atmosphere generation described above. Although described throughout as having generally polygonal shapes, faces 32, 35, 38, 41, 44, as well as any alternative embodiments of these faces, may be formed into any which allows for the correct orientation of the LEDs 50, as described above. In all of the above embodiments, LEDs 50 are driven by a power supply (not shown) which is capable of supplying constant current or adjustable pulsed current. LEDs 50 may be overdriven by the power supply to obtain greater power from LEDs 50. A control card may be employed to control the current supplied to LEDs 50. For example, one control card may control one device 20″ (FIGS. 8-9) which may, in one embodiment, include 65 LEDs 50. In another example, one control card may control thirteen strings of five LEDs each. Referring now to FIGS. 13 and 14, an alternative embodiment device 100 is shown including base 102 having bottom edge 104 and recess 106 with faces 108, 110, 112, 114, 116. Faces 108, 110, 112, 114, 116 are generally planar faces and define two-dimensional planes in which each face extends. In an exemplary embodiment, faces 108, 110, 112, 114, 116 are generally rectangular-shaped and, therefore, are elongated in at least one of two dimensions in which the faces extend. Device 100 may be used for curing inks, as described above, and may further include any or all of the structure of any other embodiment disclosed herein. Base 102 is substantially identical to base 22, described above, except as described below. Each face may include a respective copper attachment strip 109, 111, 113, 115, 117 to which are attached a plurality of LEDs 50. Heat pipes 120 may extend from top 122 of base 102 and, in one embodiment, at least one of heat pipes 120 is directly attached to a copper attachment strip 109, for example. Heat pipes 120 may include a hollow, copper tube which is sealed on both ends and which includes a wicking material in a water-based solution. Heat pipes 120 may draw heat away from each copper attachment strip and fan 124 (FIG. 14) may be used to facilitate dispersement of heat drawn away from base 102 with heat pipes 120. Thus, heat pipes 120 may be used as an active cooling device in a forced air convection system. All faces 108, 110, 112, 114, 116 extend along a longitudinal length of base 102. LEDs 50 may be disposed along faces 108, 110, 112, 114, 116 in a substantially straight line arrangement on each respective face. In one embodiment, light emitted from LEDs 50 on each respective face converges along a line centered over center or first face 112, similar to devices 20′, 20″, as described above. In one embodiment, each base 102 may have a length which measures approximately five inches. Base 102 further defines first end 126 and second end 128 between which the length extends. As shown in FIG. 13, angled or second faces 110, 114 are disposed at first angle α with respect to a plane containing face 112. In embodiments, first angle α measures between approximately 5° to approximately 90°. First angle α can be as low as approximately 5°, 10°, 15°, 20°, or 25°, or as high as approximately 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, or 30°, for example. In an exemplary embodiment, first angle α measures approximately 26.9902°. As shown in FIG. 13, angled or third faces 108, 116 are disposed at second angle β with respect to a plane containing face 112. In embodiments, second angle β measures between approximately 5° to approximately 90°. Second angle β can be as low as approximately 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, or 50°, or as high as approximately 90°, 85°, 80°, 75°, 70°, 65°, 60°, or 55°, for example. In an exemplary embodiment, second angle β measures approximately 53.9839°. Various other measurements for angle α and angle β may be chosen depending on the distance from device 100 to the substance to be cured. Additionally, the measurements of angle α and angle β may vary depending on the dimensions of base 102. For example, if base 102 is widened, the measurements for angle α and angle β may change to sustain the focused area of amplified power supplied by LEDs 50. Referring again to FIGS. 13 and 14, device 100 further includes mounting structure 130 having plates 132 and optionally connecting bars 134. Mounting structure 130 is used to mount optical culmination devices 144 to device 100, as described below. Specifically, plates 132 are used to hold optical culmination devices 144 and connecting bars 134 connect plates 132 together between first end 126 and second end 128. Connecting bars 134 are not required and may be used in one embodiment to facilitate connection of plates 132 to each first end 126 and second end 128. Connecting bars 134 may be used to guide movement of device 100 along a track, such as a printing track, for example. One plate 132 is secured to second end 128 of base 102 via fasteners 138. Connecting bars 134 are then connected to plate 132 via fasteners 138. After positioning of optical culmination devices 144, as described below, the other plate 132 is then attached to first end 126 of base 102 and connecting bars 134 via fasteners 138 secured in receiving apertures 140 in base 102 and connecting bars 134. Device 100 also includes at least one optical culmination device 144. Optical culmination device 144 does not form a part of each LED 50 and is to be distinguished from a lens component (not shown in detail) of each LED 50. Optical culmination device 144 may be formed as a cylinder, a semicylinder, or any portion of a cylinder. Optical culmination device 144 may be formed of suitable materials which transmit light waves therethrough, such as an acrylic material, a polymer material, a glass material, a ceramic material, or any combination of these materials, for example. In an exemplary embodiment, optical culmination device 144 may be formed as a clear cast acrylic rod having a diameter of approximately ⅜″, available as Item No. 44600 from United States Plastic Corporation of Lima, Ohio. In an exemplary embodiment, optical culmination device 144 is formed as a cylinder or semicylinder having a diameter as low as approximately ⅛″, ¼″, ⅜″, ½″, ⅝″, 3/4″, ⅞″, or 1″ or as high as approximately 2″, 1⅞″, 1¾″, 1⅝″, 1½″, 1⅜″, 1¼″, or 1⅛″, for example. Optical culmination device 144 is configured to culminate, i.e., intensify and climax, the light emitted from LEDs 50 of device 100. Optical culmination device 144 reorients light rays emitted from LEDs 50 from a continuously diverging pattern and causes the light rays to converge at a single area or point location at a specified distance from device 100. Device 144 may be configured to have this intensification area or point location occur at a desired distance, depending on the application of device 100. In an exemplary embodiment, optical culmination device 144 may intensify and amplify power from LEDs 50 such that, prior to placement of optical culmination device 144, the power output of device 100 is approximately 730 mW/cm2, and, subsequent to placement of optical culmination device 144, the power output of device 100 is as low as approximately 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, or 3.2 W/cm2 or as high as approximately 6.0, 5.7, 5.4, 5.0, 4.7, 4.5, 4.2, 4.0, 3.8, 3.6 or 3.4 W/cm2, for example. Thus, substantially all light emitted from each LED 50 is captured by optical culmination device 144 and refracted so as to converge at a single location or area coincident with the light emitted from all LEDs 50 of device 100. In an exemplary embodiment, a power output of approximately 3.4 W/cm2 is achieved at a distance from bottom edge 104 of base portion 102 of approximately ⅛″, and is concentrated in an area having a length of approximately three inches and a width of approximately 3/32″. In an exemplary embodiment shown in FIG. 14, a plurality of optical culmination devices 144 are secured to device 100 via mounting structure 130. Each throughbore 142 in mounting structure 130 is formed in a shape complementary to a cross-sectional shape of each optical culmination device 144. For example, as shown in FIG. 14, throughbores 142 have a generally circular shape which is complementary to the generally cylindrical shape of each optical culmination device 144. To assemble mounting structure 130 and optical culmination devices 144 to device 100, one plate 132 is secured to second end 128 of base 102 via fasteners 138. Connecting bars 134 are then connected to plate 132 via fasteners 138. Optical culmination devices 144 are positioned in substantial alignment along each row of LEDs 50 on faces 108, 110, 112, 114, 116. Each optical culmination device 144 is located in a corresponding throughbore 142 of plate 132. The other plate 132 is then attached to first end 126 of base 102 and connecting bars 134 via fasteners 138. Each throughbore 142 of plate 132 is oriented to align with each optical culmination device 144. In an exemplary embodiment, the respective ends of each optical culmination device 144 extend substantially through throughbores 142 of plates 132 and are substantially flush with the outer surfaces of plates 132. In alternative embodiments, optical culmination devices 144 may be used with any other embodiment LED device described herein, i.e., devices 144 may be sized to accommodate placement adjacent any LED 50 of any embodiment described herein. For example, devices 144 may be truncated such that devices 144 are able to be placed near LEDs 50 as shown in FIG. 1. Referring now to FIGS. 15 and 16, another alternative embodiment UV LED device 160 is shown and may include base portion 162 and a plurality of LED die packages 164. Device 160 may be used for curing inks, as described above, and may further include any or all of the structure of any other embodiment disclosed herein. Each LED die package 164 may include a plurality of LEDs 166, protective lens 168, and mount 170 for mounting LEDs 166 to base portion 162 via fasteners 172. LED die package 164 is generally available from Nichia Corporation of Japan. Device 160 also includes power cords 161 for supplying power to LEDs 166 and cooling device 176 for removing heat generated from LED die package 164 during use. Cooling device 176 may include a plurality of cooling hoses 177 and water supply hoses 178 for supplying water or other cooling solution from a source (not shown) to provide coolant for cooling device 176. Cooling device 176 may be mounted to base portion 162 via a plurality of fasteners 172. Base portion 162 includes a plurality of apertures 174 which are used for engagement with fasteners 172 to secure optical culmination device unit 180 to base portion 162. Optical culmination device unit 180 includes mounting structure 182 and optical culmination device 184. Optical culmination device 184 is substantially identical to optical culmination device 144, described above. Mounting structure 182 may include cavity 188 and a plurality of apertures (not shown) for receiving fasteners 172 inserted through apertures 174 of base portion 162. Mounting structure 182 may also include longitudinal aperture 186 which extends along a length of mounting structure 182 at least a distance equal to the longitudinal length of which LED die packages 164 extend. In an exemplary embodiment, optical culmination device 184 may substantially cover aperture 186 such that any light emitted from LED die packages 164 must traverse optical culmination device 184 prior to exiting mounting structure 182 via aperture 186. Optical culmination device 184 facilitates convergence of light emitted from LEDs 166 into a linear pattern similar to optical culmination device 144, described above, as opposed to a series of circular patterns as are emitted by LED die packages 164 without the aid of optical culmination device 184. Such a linear pattern advantageously permits further intensification of power from LEDs 166 in a desired region or point location. Although illustrated in FIGS. 15 and 16 as arranged in a linear, planar manner, LED die packages 64 may be arranged on a plurality of faces of an inverted recess, as described above with any other embodiment described herein. Furthermore, a plurality of optical culmination devices 184 may be utilized in such a configuration, which may cause the power output of device 100 to be as low as approximately 5, 10, 15, 20, or 25 W/cm2 or as high as approximately 50, 45, 40, 35, or 30 W/cm2, for example. While this disclosure has been described as having exemplary designs, the present disclosure may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains. |
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claims | 1. A fuel assembly comprising:fuel rods;two or three water rods;a tie plate arranged for supporting said two or three water rods, wherein said two or three water rods are secured to the tie plate;one or more spacers configured to support said fuel rods and said two or three water rods;a handle secured to the water rods at a respective top end of each of the water rods, anda joint arrangement,wherein the handle is secured to said two or three water rods by means of the joint arrangement, said joint arrangement being configured to transfer a vertical lifting force from the handle to said two or three water rods;said joint arrangement comprises:a balancing element arranged between said two or three water rods and the handle; wherein said joint arrangement further comprises:a first joint arranged between the balancing element and the handle;a set of second joints, where each second joint of the set of second joints is arranged between a respective one of said two or three water rods and said balancing element; whereinsaid first joint and said set of second joints are configured to allow a rotational movement of said balancing element in relation to said handle as well as in relation to said two or three water rods, and whereinsaid first joint and each one of said second joints comprise a pair of spherically rounded joint surfaces. 2. A fuel assembly according to claim 1, wherein said first joint is centrally arranged in relation to the second joints. 3. A fuel assembly according to claim 1, wherein said pair of spherically rounded joint surfaces of said first joint comprises one spherically rounded joint surface on the handle and one spherically rounded joint surface on the balancing element, and wherein the spherically rounded joint surfaces of said pair of spherically rounded joint surfaces of the first joint are arranged in contact with each other. 4. A fuel assembly according to claim 1, said first joint comprising distance means configured to provide a clearance for rotation of the balancing element in relation to the handle. 5. A fuel assembly according to claim 1, wherein a respective fastener is secured to the top portion of each water rod and wherein each of said pairs of spherically rounded joint surfaces of said second joints comprises one spherically rounded joint surface on the fastener and one spherically rounded surface on the balancing element, so that the balancing element comprises one spherically rounded joint surface for each fastener, and wherein the spherically rounded joint surfaces of each of said pairs of spherically rounded joint surfaces of the set of second joints are arranged in contact with each other. 6. A fuel assembly according to claim 5, wherein each respective fastener comprises a nut, wherein a bottom side of each nut comprises a respective one of the spherically rounded joint surfaces of the set of second joints. 7. A fuel assembly according to claim 1, wherein said balancing element comprises two or three through-going holes, wherein each one of said two or three water rods extends through one of the through-going holes so that one water rod extends through each through-going hole, and wherein each of said through-going holes is configured with an internal diameter that provides a clearance for the respective water rod thereby allowing rotational movement of the balancing element in relation to each water rod. 8. A fuel assembly according to claim 1, wherein the number of said two or three water rods are three. 9. A fuel assembly according to claim 1, wherein the number of said two or three water rods are two. 10. A fuel assembly according to claim 1, wherein the balancing element consists of a single element, said single element being provided with said spherically rounded surface of the first joint on its bottom side, and being provided with said spherically rounded surfaces of the second joint on its top side. 11. A fuel assembly according to claim 10, wherein said single element is a plate-like element. 12. A fuel assembly according to claim 1, wherein said balancing element is arranged to rotate upon experiencing mutually different vertical forces from the water rods during lifting. 13. A fuel assembly according to claim 1, configured to be arranged inside a channel and wherein the tie plate, the spacer, the fuel rods and the water rods are configured for being lifted out of the channel. 14. A fuel assembly according to claim 1, further comprising a channel, wherein the handle is attached to the channel and wherein the tie plate, the spacer, the fuel rods and the water rods are configured for being lifted together with the channel. |
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abstract | An apparatus for use in making localized passive measurements of electromagnetic radiation emitted from an object located in a radioactive environment includes a hollow elongate conduit having a first end, a second end, and a reflective inner surface. The first end of the conduit is positionable in the radioactive environment proximate the object, and the second end of the conduit is positionable outside the radioactive environment. The conduit has at least one bend between the first end and the second end, such that light entering the first end of the conduit is reflected by the inner surface of the conduit at least once as it travels through the conduit before reaching the second end. A detector in optical communication with the second end of the conduit is configured to detect electromagnetic radiation that reaches the second end. |
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abstract | The feedwater controller of a nuclear power plant having three or more feedwater pumps supplying water to the reactor vessel, electric motors driving the feedwater pumps and electric power converters connected to the electric motors is equipped with a flow rate controller and a trip compensation means. The flow rate controller calculates a flow rate to the reactor vessel based on a detected value indicating a condition of the nuclear power plant and a preset value of the water level of the reactor vessel, and generates a rotation speed command signal for the electric motors based on the flow rate command signal. The trip compensation means increases the rotation speed of the electric motors not having tripped if one of the feedwater pumps trips. |
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claims | 1. A nuclear reactor module, comprising:a reactor vessel;a pressurizer located at an upper portion of the reactor vessel;a reactor core located at a lower portion of the reactor vessel;a baffle assembly located between the reactor core and the pressurizer; anda reactor housing having an inward-facing portion and a flow path through the reactor housing that fluidly couples the reactor core to a lower portion of the baffle assembly, the inward-facing portion comprising a curvature for reducing turning loss of a coolant flowing past the inward-facing portion, the inward-facing portion of the reactor housing comprising multiple wing-shaped extensions located about a perimeter of an upper portion of the reactor housing. 2. The nuclear reactor module of claim 1, wherein a cross section of the inward-facing portion comprises an airfoil. 3. The nuclear reactor module of claim 2, wherein the inward-facing portion of the reactor housing is disposed about a perimeter of an upper portion of the reactor housing. 4. The nuclear reactor module of claim 1, wherein the baffle assembly comprises a lower baffle plate including an ellipsoidal surface having a perimeter that is larger than the inward-facing portion of the reactor housing. 5. The nuclear reactor module according to claim 4, wherein the ellipsoidal surface of the lower baffle plate directs the coolant towards the lower portion of the reactor vessel. 6. The nuclear reactor module according to claim 1, wherein the inward-facing portion of the reactor housing includes a cross section that approximates an inverted teardrop. 7. The nuclear reactor module according to claim 1, wherein the inward-facing portion of the reactor housing includes a cross section that increases in thickness towards an upper portion of the reactor housing. 8. The nuclear reactor module according to claim 7, wherein the upper end of the reactor housing comprises a perimeter that includes a rounded rim. 9. A baffle assembly for use in a nuclear reactor module, comprising:an upper baffle plate exposed to a pressurized volume of saturated coolant; anda lower baffle plate exposed to subcooled coolant, the subcooled coolant in fluid communication between a location proximate to a portion of the lower baffle plate and a location proximate with the upper baffle plate, wherein one or more of the upper baffle plate and the lower baffle plate are heated by the saturated coolant. 10. The baffle assembly of claim 9, wherein a flow path created by a separation of the upper baffle plate and the lower baffle plate is of sufficient length to prevent an insurge of coolant from a volume proximate with the lower baffle plate. 11. The baffle assembly of claim 9, wherein the upper baffle plate is heated by the pressurized volume of saturated coolant. 12. The baffle assembly of claim 9, wherein the peripheral portion of the lower baffle plate curves in a direction towards a lower portion of the nuclear reactor module. 13. The baffle assembly of claim 9, wherein the lower baffle plate comprises a bullet-shaped tip at a central portion. 14. The baffle assembly of claim 13, wherein the lower baffle plate curves downward at a peripheral portion. 15. An upper portion of a nuclear reactor module, comprising:a pressurizer region; anda baffle assembly below the pressurizer region, the baffle assembly comprising:an upper baffle plate proximate with the lower portion of the pressurizer region; anda lower baffle plate below the upper baffle plate, wherein the lower baffle plate comprises a surface that curves downward toward a peripheral region of the lower baffle plate. 16. The upper portion of the nuclear reactor module of claim 15, further comprising an upper portion of a riser having a curved inward-facing portion for reducing turning loss of coolant circulating from a lower portion of the nuclear reactor module. 17. The upper portion of the nuclear reactor module of claim 16, wherein the curved inward-facing portion of the riser extends continuously about a perimeter of the upper portion of the riser. 18. The upper portion of the nuclear reactor module of claim 15, further comprising a divider for directing coolant in an outward direction from a center of the lower baffle plate. 19. The upper portion of the nuclear reactor module of claim 15, wherein the lower baffle plate is defined by a shape selected from the group consisting of an ellipsoid, a dome, a hemisphere, and a concave surface. |
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abstract | An accelerator neutron source (ANS) including a field ionization (FI) array configured to generate deuterium and tritium ions and a plasma for containing the deuterium and tritium ions produced by the FI array. The ANS also includes a target comprising deuterium and tritium ions and the ANS is configured to accelerate deuterium and tritium ions produced by the FI array toward the target to generate neutrons by applying a voltage to an accelerating electrode. |
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046410333 | abstract | An apparatus and method for maintaining an optical element at a sufficiently high temperature during transmission of radiation by the optical element to prevent radiation degradation of the optical element by an increase in the absorption of at least one wavelength of the radiation. The material of the optical element is such that the absorption of the wavelength(s) concerned temporarily decreases upon annealing the optical element. The optical element may be kept at the temperature required by a wide variety of heating techniques, including gas convection heating, direct contact heating, and radiant heating. The heated optical element may be employed in optical systems for transmitting radiation from a source of radiation to a target to be exposed to this radiation. |
abstract | A flat-panel detector includes: a ray-conversion layer configured to convert rays into a light having a first wavelength; and a plurality of imaging units. At least one of the plurality of imaging units includes: a photo sensor configured for receiving the light and converting the light to an electrical signal; and a light guider located a side of the photo sensor adjacent to the ray-conversion layer, the light guider having a light entry surface adjacent to the ray-conversion layer and a light exit surface adjacent to the photo sensor, the light entry surface being configured to receive the light from the ray-conversion layer and having an area greater than an area of the light exit surface, and an orthogonal projection of the light exit surface in a direction perpendicular to the ray-conversion layer at least partially overlapping that of the photo sensor. |
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059206012 | summary | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to apparatus and methods for delivery of neutron beams for medical therapy. More particularly, it concerns a neutron delivery system with a bimodal energy spectrum that can be used for both fast-neutron therapy and for fast-neutron therapy augmented by boron neutron capture therapy. 2. Background Art Although the prior art for neutron therapy is voluminous, the prior art fails to disclose the bimodal energy spectrum of the present invention. For example, see the following prior art references: U.S. Pat. No. 5,392,319, Feb. 21, 1995, Accelerator-based neutron irradiation, Eggers Phillip E., Dublin, Ohio. U.S. Pat. No. 4,666,651, May 19, 1987, High energy neutron generator, Barjon, Robert, Grenoble, France Breyaat, Genevieve, Brignod, France. U.S. Pat. No. 4,139,777, Feb. 13, 1979, Cyclotron and neutron therapy installation incorporating such a cyclotron, Rautenbach, Willem L., 18 Unie Ave., Stellenbosh, Cape Province, South Africa. U.S. Pat. No. 4,112,306, Sep. 5, 1978, Neutron irradiation therapy machine, Nunan, Craig S., Los Altos Hills, Calif. U.S. Pat. No. 3,781,564, Dec. 25, 1973, NEUTRON BEAM COLLIMATORS, Lundberg, Derek Anthony Hatfield, England. U.S. Pat. No. 3,715,597, Feb. 6, 1973, ROTATABLE NEUTRON THERAPY IRRADIATION APPARATUS, Hoffmann, Ernst-Gunther, Hamburg, Germany, Federal Republic of Meyerhoff, Kaus, Hamburg, Germany, Federal Republic of Offermann, Bernd Peter, Hamburg, Germany, Federal Republic of Barthel, Rolf, Hamburg, Germany, Federal Republic of Germany. Application of neutrons for radiotherapy of cancer has been a subject of considerable clinical and research interest since the discovery of the neutron by Chadwick, in 1932. Fast neutron radiotherapy was first used by Robert Stone in the Lawrence Berkeley Laboratory in 1938. This technology has evolved over the years to the point where it is now a reimbursable modality of choice for inoperable salivary gland tumors, and it is emerging, on the basis of recent research data, as a promising alternate modality for prostate cancer, some lung tumors, and certain other malignancies as well. Neutron capture therapy (NCT), a somewhat different form of neutron-based therapy, was proposed in the mid 1930s and, despite some notable failures in early U.S. trials, has attracted a great deal of renewed research interest lately, due to significant improvements in the relevant technology and radiobiological knowledge. The basic physical processes involved in fast neutron therapy and neutron capture therapy differ in several respects. In fast neutron therapy, neutrons having relatively high energy (approximately 30-50 MeV) are generated by a suitable neutron source and used directly for irradiation of the treatment volume, just as is done with standard photon (x-ray) therapy. Delivery of fast-neutron therapy for cancer is typically accomplished using accelerator based fast neutron sources that generally involve targeting a proton or deuteron beam onto beryllium. Currently available systems employ various types of cyclotron or liner accelerator technology to deliver the necessary proton beam, which impinges on a suitable target, producing neutrons that are subsequently collimated and delivered to the patient via either a fixed beam delivery system, or by a rotating isocentric structure. In neutron capture therapy, a neutron capture agent, which in current practice is boron-10 (yielding Boron NCT, or BNCT) is selectively taken into the malignant tissue following the administration of a suitable boronated pharmaceutical, preferably into the bloodstream of the patient. At an appropriate time after boron administration, the treatment volume is exposed to a field of thermal neutrons produced by application of an external neutron beam. The thermal neutrons interact with the boron-10, which has a very high capture cross section in thermal energy range and which, ideally, is present only in the malignant cells. Each boron-neutron interaction produces an alpha particle and a lithium ion. These highly-energetic charged particles deposit their energy within a geometric volume that is comparable to the size of the malignant cell, leading to a high probability of cell inactivation by direct DNA damage. Because boron is ideally taken up only in the malignant cells, the NCT process offers the possibility of highly selective destruction of malignant tissue, with cellular-level separating of neighboring normal tissue since the neutron sources used for NCT are, themselves, designed to produce a minimal level of damage of normal tissue. When BNCT is administered as a primary therapy, an epithermal-neutron beam (neutrons having energies in the range of 1 eV to 10 keV) is used to produce the required thermal neutron flux at depth, since these somewhat higher-energy neutrons will penetrate deeper into the irradiation volume before thermalizing, yet they are still not of sufficient energy to inflict unacceptable damage to intervening normal tissue. A third form of neutron therapy, which is basically a hybrid that combines the features of fast neutron therapy and NCT is also currently a subject of research interest, and constitutes the field of application where this invention is useful. In this type of radiotherapy, a neutron capture agent is introduced preferentially into the malignant tissue prior to the administration of standard fast neutron therapy. Because a small fraction of the neutrons in fast neutron therapy will be thermalized in the irradiation volume, it is possible to obtain a small incremental absorbed dose from the neutron capture interactions that result. Improved tumor control relative to fast neutron therapy alone using the augmentation concept is clearly promising based on current radiobiological research. However, until now, no NCT augmentation system has been developed that makes a significant improvement over the unaugmented fast neutron therapy. Additionally, prior art fast-neutron therapy systems are largely located only at major research centers due to the fact that they are physically complex, bulky and require high-level operating staffs to maintain. In general these systems are not well suited for wide-spread, practical, clinical deployment. BRIEF SUMMARY AND OBJECTS OF THE INVENTION The present invention provides a potentially compact, user friendly, field-deployable neutron delivery system with dual capabilities for fast neutron therapy alone, or for fast neutron therapy with neutron capture therapy augmentation, with much improved capability for tumor control during neutron beam treatment. It is an object of the present invention to provide improved capability for tumor control during medical therapy through means of superior control of a neutron beam. The present invention is a neutron delivery system that provides improved capability for tumor control by producing a specially tailored neutron beam. The specially tailored neutron beam has a bimodal energy spectrum and provides dramatically enhanced tumor control during medical therapy by allowing neutron therapy to be enhanced with neutron capture therapy. The system includes: a structure for producing a proton beam; at least one target; and a magnet arrangement for directing the proton beam into the at least one target. The target includes layers for producing, when impacted by the proton beam, at least one neutron beam having a bimodal energy spectrum for use with both fast-neutron therapy and boron neutron capture therapy. Finally, the neutron beam passes through a collimator prior to delivery to a patient. Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. |
045487820 | description | DESCRIPTION OF THE PREFERRED EMBODIMENT In the present invention, an intense, space-charge-neutralized, pulsed ion beam is utilized to heat a tokamak plasma. The term "space-charge-neutralized" is used herein to indicate that the intense ion beam contains an equal number of ions and electrons (although the electrons may be of much lower energy than the ions) so that the ion beam used in the present invention may be thought of as an intense, neutral, plasma beam. The intense ion beam is injected into the tokamak before the plasma is fully formed, the remainder of the plasma is formed around the beam, and the beam transfers its energy to the plasma by inelastic collisions with the electrons and ions of the plasma. Referring now to the drawings wherein like reference characters refer to like or corresponding parts throughout the several views and, more particularly to FIG. 1, there is illustrate a first embodiment of the apparatus for heating a tokamak-confined plasma to thermonuclear temperatures. A basic tokamak magnetic field apparatus 10 includes a toroidal shell 12 defining an endless chamber 14. The chamber 14 is evacuated to a high vacuum and a high-density, low-volume plasma 16 (hereinafter also referred to as the target plasma) is established in the chamber by means not shown. The target plasma 16 of major radius R and minor radius r.sub.o is confined within the shell 12 in a helical magnetic field B created by the superposition of a strong, externally generated toroidal field B.sub.t and a poloidal field B.sub.p generated by the plasma current I. (The characters B, B.sub.t and B.sub.p are used herein to denote the vector magnetic fields). A toroidal winding 18, energized by a direct-current voltage source, not shown, establishes the toroidal (longitudinal) magnetic field B.sub.t while the plasma current I is induced by transformer action (the plasma acts as a transformer secondary winding) produced by primary windings 19 magnetically linked to the toroidal shell 12. A vacuum region 20 surrounds the plasma 16 in the chamber 14. Although the plasma current has the basic function of providing the rotational transform needed for plasma equilibrium, it has the incidental benefit of ohmically heating the target plasma to temperatures on the order of 1 keV. However, since much higher temperatures are required to sustain a thermonuclear reaction (approximately 10 keV in the case of a T, D type reaction), additional heating of the target plasma is required. In order to heat the target plasma by injecting a space-charge-neutralized, pulsed ion beam into the target plasma, five things must be accomplished: first, an ion beam having the required characteristics (these characteristics will be explained hereinafter) must be produced; second, the ion beam must propagate to the tokamak and must propagate across the magnetic field in the vacuum region of the tokamak; third, the ion beam must be trapped by the target plasma; fourth, the remainder of the plasma must be formed around the beam and target plasma; and fifth, the beam must transfer its energy to the plasma in a time of the order of, or less than, the plasma's energy containment time. Considering first the production of an ion beam having the proper characteristics, in general an electron beam and an ion beam may be generated in an ion accelerator which includes an anode and a cathode separated by an anode-cathode gap and in which the anode and cathode are capable of emitting ions and electrons, respectively. Until recently, the ratio of power delivered to the ion beam to the power delivered to the electron beam was low; however, advances in ion accelerators have greatly increased the portion of the energy delivered to the anode-cathode gap which goes to producing the ion beam. Referring still to FIG. 1, the first embodiment of the present invention includes a pulsed ion-accelerator means 22 of the type capable of producing an intense, space-charge-neutralized ion beam. A reflex triode, reflex tetrode, a pinched electron diode or magnetically insulated diode is suitable for use as ion-accelerator means 22. Typically, ion-accelerator means 22 will include an anode 24 and a cathode 26 separated by an anode-cathode gap d. The ion-accelerator means 22 is energized by a pulsed power generator 28 which typically includes a capacitor bank connected in the form of a conventional Marx generator or pulse transformer 30 and a conventional pulse-forming line 32. Marx generator 30 provides the high voltage necessary to generate the intense ion beam and pulse-forming line 32 provides rapid delivery of the energy to the ion-accelerator means 22. Ion-accelerator means 22 and pulsed power generator 28 are well known in the art and are disclosed in U.S. Pat. No. 4,115,191 hereby incorporated by reference. The ion-accelerator means 22 is situated in a guide tube 34 which leads to an opening 36 (see FIG. 2) in a side wall of the tokamak shell 12. The guide tube 34 is attached nearly tangent to the side wall. The ion accelerator means 22 and the guide tube 34 are subjected to a longitudinal magnetic field B.sub.G generated by guide tube winding 38 (energized by a direct-current supply not shown). The operation of the ion-accelerator means 22 will now be briefly described. Upon being energized by the pulsed-power generator 30, an ion current is drawn from anode 24 and passes through the cathode 26. The ion accelerator means 22 is designed so that the ion beam-to-electron beam current ratio is enhanced by preventing the generation of electron current. The ion beam, represented by dashed lines 40, emerging from the cathode 26 is neutralized by electrons dragged off plasma which has been formed on the outside surface of the cathode. In the case of an ion accelerator having a planar anode-cathode gap d (in centimeters) with an applied voltage V (in megavolts), according to the Langmuir-Child law, the ion-current density produced (in amperes/cm.sup.2) is ##EQU1## where .epsilon..sub.o is the permittivity of free space, M is the mass of a proton (in MKS units), and PA1 e is the charge of a proton (in MKS units), PA1 j.sub.LC is the ion current density, and PA1 e is the proton charge. PA1 c is the speed of light. if it is assumed that no electrons are present in the gap. In fact, the presence of electrons in the gap d allows the possibility that the space-charge-limited ion current can be enhanced by a factor a (a=j.sub.i /j.sub.LC, where j is the actual current density). For example, reflex triode operation with enhancement factors of approximately 100 has been observed. Considering now the injection of the space-charge-neutralized ion beam 40 into the tokomak 10, reference is made to FIG. 2. The pulsed ion-accelerator means 22, such as a reflex triode, is shown situated in the guide tube 34 which leads to the opening 36 in the side wall of the tokamak shell 21. The ion beam 40 emerging from the anode 24 and passing through the cathode 26 (neutralized as previously indicated by dragging electrons from the cathode) will propagate down the guide tube 34. At the end of the guide tube 34, the magnetic field in the guide tube B.sub.G (as generated by guide tube winding 38) merges with the tokamak magnetic field B. The ion beam 40 propagating through the guide tube 36 into the tokamak enters the tokamak nearly tangential to the field lines. The ion beam 40 must propagate across the vacuum magnetic field region 20 to reach the target plasma. As is well known, a neutralized group of ions and electrons can move across a vacuum magnetic field essentially unimpeded, if .omega..sub.pi.sup.2 >>.OMEGA..sub.i.sup.2, where .omega..sub.pi and .OMEGA..sub.i are the ion plasma frequency and gyrofrequency of the ion beam 40, respectively. In MKS units, .omega..sub.pi.sup.2 =ne.sup.2 /.epsilon..sub.o M and .OMEGA..sub.i.sup.2 =eB/M, where e is the proton charge, M is the proton mass, B is the magnetic field strength, .epsilon..sub.o is the permittivity of free space, and n is the beam density. As illustrated in FIG. 3 which shows a cross-section of the beam 40 within the vacuum region 20 (as viewed from the tokamk toward the guide tube 34), for .omega..sub.pi.sup.2 >>.OMEGA..sub.i.sup.2 charge separation within the beam due to adiabatic guiding center inertial drifts will set up a polarization field in the beam EQU E.sub.o =-V.sub.o X B where V.sub.o is the beam velocity in the guide tube. In order for the foregoing relationships to be valid, the beam density n must be sufficiently large that .omega..sub.pi.sup.2 >>.OMEGA..sub.i.sup.2. From the Langmuir-Child law the beam density is EQU n=j.sub.LC /eVo (2) where Substituting for the ion current density j.sub.LC from equation (1) and substituting .sqroot.2eV.multidot.M for the beam velocity V.sub.o gives a beam density EQU n.apprxeq.(3.times.10.sup.11).alpha.V/d.sup.2 (cm.sup.-3) where V (the applied voltage) is in megavolts and d (the anode-cathode gap) is in centimeters and the enhancement factor .alpha. has been included. It will be apparent to persons skilled in the art that n can be increased by converging the magnetic field B.sub.G in the guide tube 34. As will be evident from the example treated hereinafter, the condition .omega..sub.pi hu 2 >>.OMEGA..sub.i.sup.2 can easily be achieved. It is further noted that if the ions emerging from ion accelerator means 22 are not space-charge-neutralized by the addition of electrons, they will only propagate (in the vacuum region 20) a distance on the order of their Larmor radius, a distance too short to be of interest in this application. As was shown above, when the ion beam 40 passes from the guide tube 34 into the tokamak 10 a polarization electric field E.sub.o is set up which gives the E.sub. .times.B drift necessary for propagation. After the beam 40 has propagated from the wall through the vacuum region 20, it must be trapped by the target plasma. Considering the trapping of the ion beam by the target plasma, reference is made to FIG. 4 which shows the beam 40 striking the plasma 16. Each magnetic field line in the beam 40 must be at a different potential in order to maintain the polarization field E.sub.o which converts the beam. However, the potential of the target plasma 16 is the same on different field lines because the plasma is a good conductor. Therefore the target plasma short-circuits the polarization field E.sub.o and traps the beam at the outside of the plasma. The trapped beam travels around the chamber 14 on the surface of the target plasma. After the beam 40 has been trapped by the target plasma, the remainder of the plasma must be formed around the beam and target plasma, and the beam must transfer its energy to the plasma. Considering first the formation of the remainder of the plasma around the beam and target plasma, reference is made to FIG. 1. A fast pulsed valve 44 is shown situated in the side wall of the tokamak shell 12. The volume of the plasma is increased by injecting a puff of gas into the chamber 14 with the fast pulsed valve 44. The injected puff of gas produces a cold gas blanket around the target plasma and the beam which is ionized either by the target plasma and the beam, or by some other means (e.g., radio-frequency breakdown) and thereby increases the volume of plasma to its final value. The technique of "fast gas puffing" is well known in the art and is described, for example, in "High Density and Collisional Plasma Regimes in the Alcator Program" by E. Apgar et al., Plasma Physics and Controlled Nuclear Fusion Research, 1976, Vol. 1 (1976), hereby incorporated by reference. Considering now the transfer of energy by the beam to the plasma, after formation of the remainder of the plasma around the beam and the target plasma, the transformer which drove the initial target plasma current is shut down (i.e., the magnetizing current in the primary windings 19 ceases) and the total tokamak current necessary for creation of the poloidal magnetic field is now carried in the ion beam 40. As the ion beam slows down, it heats the electrons and ions by classical collisions. The total current does not decrease as fast as the beam current does, because of the inductance of the system. When the beam has finally lost all of its energy, the plasma is heated to a sufficiently high temperature that the tokamak current decays very slowly. Referring to FIG. 5, there is illustrated a second embodiment of the apparatus for heating a tokamak-confined plasma to thermonuclear temperatures. A basic tokamak magnetic field apparatus 10 includes a toroidal shell 12 defining an endless chamber 14. The chamber 14 is evacuated to a high vacuum, and a low density (larger than the ion beam density) high-volume plasma 16 (hereafter also referred to as the tokamak plasma) is established in the chamber by means not shown. The tokamak plasma 16' of major radius R and minor radius equal to the radius of the shell 12, is confined within the shell in a magnetic field B created by the superposition of a strong, externally generated toroidal field B.sub.t and a much smaller vertical field B.sub.v parallel to the axis of the shell 12. (The characters B, B.sub.t and B.sub.v are used herein to devote the vector magnetic fields). A toroidal winding 18, energized by a direct current source, not shown, establishes the toroidal (longitudinal) magnetic field B.sub.t, while longitudinal coils 19, also energized by a direct current source, not shown, establish the vertical magnetic-field B.sub.v. No plasma current is carried by the tokamak plasma. In order to heat the tokamak plasma by injecting a space-charge-neutralized, pulsed ion beam into the target plasma, five things must be accomplished: first, an ion beam having the required characteristics must be produced; second, the ion beam must propagate to the tokamak, third, the ion beam must be trapped by the tokamak plasma; fourth, the remainder of the plasma must be formed around the beam, and fifth, the beam must transfer its energy to the plasma in a time comparable to, or less than, the plasma energy containment time. Considering first the production of an ion beam having the proper characteristics, reference is made to FIG. 5. The second embodiment of the present invention includes a pulsed ion-accelerator means 22 as described hereinabove of the type capable of producing an intense, space-charge-neutralized ion beam. Typically, ion accelerator means 22 will include an anode 24 and a cathode 26 separated by an anode-cathode gap d. The ion accelerator means 22 is energized by a pulsed power generator 28 which typically includes a capacitor bank connected in the form of a conventional Marx generator or pulse transformer 30 and a conventional pulse-forming line 32. Marx generator 30 provides the high voltage necessary to generate the intense ion beam and pulse-forming line 32 provides rapid delivery of the energy to ion-accelerator means 22. The ion accelerator means 22 is situated in a guide tube 34 which leads to an opening 36 (FIG. 6) in the top wall of the tokamak shell 12. The guide tube is attached nearly tangent to the top wall. The ion accelerator means 22 and the guide tube 34 are subjected to a longitudinal magnetic field B.sub.G generated by guide tube windings 38 (energized by a direct current supply not shown). Considering now the injection of the space-charge-neutralized ion beam 40 into the tokamak 10, reference is made to FIG. 6. The pulsed ion-accelerator means 22, such as a reflex triode, is shown situated in the guide tube 34 which leads to the opening in the top wall of the tokamak shell 12. If the vacuum requirements for the ion source and tokamak are different, a thin foil transparent to the beam can be placed somewhere in the guide tube or else at the opening between guide tube and tokamak. The ion beam 40 emerging from the anode 24 and passing through the cathode 26 (neutralized by dragging electrons from the cathode) will propagate down the guide tube 34. At the end of the guide tube 34, the magnetic field in the guide tube B.sub.G (as generated by guide tube winding 38) merges with the tokamak magnetic field B. The ion beam 40 propagating through the guide tube 36 into the tokamak enters the tokamak nearly tangential to the field lines. After the beam 40 has entered the tokamak it must be trapped by the tokamak plasma 16'. Considering the trapping of the ion beam by the tokamak plasma, reference is made to FIG. 7 which shows the ion beam 40 entering the chamber 14 nearly tangential to the toroidal magnetic field lines. When the ion beam 40 passes into the tokamak 10, the ion beam current inductively generates an equal and oppositely directed plasma current so that no net current is produced in the tokamak. Since there is no tokamak current, the ion beam responds only to the toroidal magnetic field B.sub.t and the vertical magnetic field B.sub.v. The beam ions will have a large velocity component v.sub..parallel. parallel to the toroidal field B.sub.t, and a slow downward drift velocity component v.sub..perp. parallel to the vertical field B.sub.v whose magnitude is given by ##EQU2## The plasma current decays rapidly because at low density and high current there is a large anomalous resistivity (Lampe, Manheimer, McBride and Orens, Phys. Fluids 15, 2356 (1972)), whereas the ion beam current decays slowly by classical collisions of beam ions with plasma electrons. The condition for anomalous resistivity is given approximately by ##EQU3## where v.sub.o is the electron drift velocity, m and M are respectively the electron and ion masses, and T.sub.e and T.sub.i are respectively the electron and ion temperatures. If there is anomalous resistivity, the electron-ion collision frequency is given approximately by .sup..omega. pe/1000 where .sup..omega. pe is the electron plasma frequency. Thus, as the beam ions drift downward, a net tokamak current necessary for creation of the poloidal magnetic field is generated. The pinch forces on the ion beam can stop the downward drift and trap the beam on a given magnetic field surface when the net tokamak current ##EQU4## where a is the radius of the ion beam, and By varying B.sub.v and the density of the tokamak plasma, it is possible to optimize this process. (Varying the plasma density varies the rate at which the plasma current decays). After the beam 40 has been trapped by the tokamak plasma, the remainder of the plasma must be formed around the beam so that the beam can transfer its energy to the plasma. Considering first the formation of the remainder of the plasma around the beam, reference is made to FIG. 5. A fast pulsed valve 44 is shown situated in the side wall of the tokamak shell 12. The density of the plasma is increased by injecting a puff of gas into the chamber 14 with the fast pulsed valve. The injected puff of gas permeates the plasma and is ionized either by the plasma and the beam, or by some other means (e.g., radio-frequency breakdown) and thereby increases the density of the plasma to its final value. Considering now the transfer of energy by the beam to the plasma, after formation of the remainder of the plasma around the ion beam, total tokamak current is carried by the ion beam 40. As the ion beam slows down, it heats the electrons and ions by classical collisions. The total current does not decrease as fast as the beam current does, because of the inductance of the system. When the beam has finally lost all of its energy, the p1asma is heated to a sufficiently high temperature that the current decays very slowly. Reference is made to "The Transient Tokamak", Naval Research Laboratory Memorandum Report 4142 (December 1979) by the present inventors wherein it is shown that for high field, high density plasma, a single pulse of ion beam energy (about 1 megajoule) is sufficient to reach ignition. Specifically, numerical solutions for the Alcator C device at MIT are shown in FIG. 1 therein. It is assumed that the fully-formed plasma minor radius r=10 cm, the major radius R=60 cm, the plasma density n=10.sup.15 cm.sup.-3 and B=160 KG. A 5 megavolt, 1.5 megamp., 200 nanosecond tritium beam (of energy E=1.5 megajoules) shot into a deuterium-tritium plasma causes the plasma to ignite and, after the numerical integration stops at t=1 second, the energy multiplication factor (ratio of the output power derived from the fusion reaction to the input power required to heat the plasma) Q exceeds 12. The ion beam heating approach has several advantages over ohmic heating. Chiefly, there is the enormous power of the beam. The 1.5 megajoules of beam energy is deposited in about 100 milliseconds representing an initial power dissipation of 15 Megawatts. Secondly, before the beam slows down, it deposits the last bit of its energy into the plasma. In this case, it leads to an ion temperature increase of about 2 keV and this final boost leads directly to ignition. Also, additional calculations show that for Alcator C, a derated beam (V=2 Mev I=1 Meg Amp) and derated field (B.apprxeq.80 KG) can give rise to Q.apprxeq.1. Furthermore, ion beam heating can also give rise to breakeven on large volume tokamaks. Although the present invention has been described with application to the heating of a tokamak-confined plasma, those skilled in the art will recognize that the present invention can be used with other fusion schemes in which a plasma is confined in a magnetic field, specifically, linear plasma-confining magnetic field devices (magnetic mirrors) or other toroidal confining devices such as tormak or surmac. It is obvious that many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as described. |
abstract | An apparatus for simultaneous parallel processing of a sample using light energy for optical viewing or surface processing in parallel with a charged particle beam. A charged particle beam transmits a focused ion beam or an electron beam along a path to a sample. An optical microscope transmits light along a first path to the sample, and a prism aligned along the first light path reflects light into a second light path toward the sample. A portion of the prism and reflective surface is removed for passage of the charged particle beam. A lens is aligned along the second light path and has a portion removed for passage of the charged particle beam. The removed portions of the prism and lens are aligned along the charged particle beam path to permit parallel delivery of the charged particle beam and the light to substantially the same portion of the sample. |
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abstract | A container for a non-irradiated nuclear fuel assembly including a single casing for receiving at least one nuclear fuel assembly, the casing being formed from an elongate tubular shell, the shell including a metallic internal layer delimiting at least one individual housing for receiving a nuclear fuel assembly, and a metallic external layer surrounding the internal layer, the shell being filled between its internal layer and its external layer, and from lids for closing the or each housing at the longitudinal ends of the shell. |
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abstract | The present invention relates to an universal method for the large scale production of high-purity carrier free or non carrier added radioisotopes by applying a number of “unit operations” which are derived from physics and material science and hitherto not used for isotope production. A required number of said unit operations is combined, selected and optimized individually for each radioisotope production scheme. The use of said unit operations allows a batch wise operation or a fully automated continuous production scheme. The radioisotopes produced by the inventive method are especially suitable for producing radioisotope-labelled bioconjugates as well as particles, in particular nanoparticles and microparticles. |
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description | This application is a divisional application of U.S. patent application Ser. No. 15/004,128, filed Jan. 22, 2016, which is herein incorporated by reference in its entirety. This invention was made with Government support under Contract No. DE-NE0000633 awarded by the Department of Energy. The Government has certain rights in this invention. In known pressurized water reactors (PWR) and boiling water reactors (BWR), a reactor core may contain a large number of fuel rods that are several meters in height. The reactor core may be surrounded by water contained within a reactor vessel. Additionally, the reactor may contain in-core instrumentation including a number of instrument assemblies located in the reactor core. During maintenance or refueling operations, in which some or all of the fuel rods in the reactor core may be inspected or replaced, respectively, the reactor vessel must be at least partially disassembled or removed in order to gain access to the reactor core. Prior to disassembling the reactor vessel, the in-core instrumentation may be disconnected and physically removed from the reactor core by opening the reactor vessel penetrations and pulling the in-core instrumentation out of the reactor core. However, in order to remove the in-core instrumentation, an operator and/or tool is typically introduced into the containment vessel in order to access the in-core instrumentation. For example, the containment structure may comprise a man-way that is large enough for an operator to enter a containment region located above the reactor pressure vessel. Work conditions and precautionary measures may be established to allow operators to position themselves on top of the reactor pressure vessel head to withdraw the in-core instruments. To withdraw an instrument, the operator may loosen a Swagelok fitting for each in-core instrument and physically grasp the external end of the in-core instrument, which may comprise a forty to eighty foot long tube or cable. The operator then pulls about fifteen feet of the in-core instrument through the reactor pressure vessel such that the lower end of the in-core instrument is withdrawn from the reactor core. Withdrawing the in-core instrumentation via known refueling operations may therefore not only require providing access to the inside of containment, but the refueling tool or operator may also need to be placed in close physical proximity to the reactor core in order to loosen or open the Swagelok fitting located on top of the reactor pressure vessel. Accordingly, two of the primary means of reducing potential radiation exposure, namely providing shielding from and maintaining distance to a radioactive source, may be compromised in known refueling operations. Alternatively, if the in-core instrumentation and reactor core are first allowed to cool down and/or become less radioactive before the operator or tool is used, then a significant amount of time may transpire in which the reactor module is taken off-line and is unable to generate electricity. This application addresses these and other problems. An in-core instrumentation system for a reactor module is disclosed herein. The in-core instrumentation system may comprise a plurality of in-core instruments connected to a containment vessel and a reactor pressure vessel at least partially located within the containment vessel. A reactor core may be housed within a lower head that is removably attached to the reactor pressure vessel, and lower ends of the in-core instruments may be located within the reactor core. The in-core instruments are configured such that the lower ends may be concurrently removed from the reactor core as a result of removing the lower head from the reactor pressure vessel. A method for withdrawing in-core instrumentation from a reactor module is disclosed herein. The method may comprise initiating a shut-down procedure for a reactor core located within a reactor pressure vessel. A sealed reactor module may be transported to a refueling pool. The sealed reactor module may comprise the reactor pressure vessel housed within a containment vessel, and in-core instrumentation may be at least partially located within the reactor core while the sealed reactor module is being transported. A lower containment head of the containment vessel may be removed in the refueling pool. Additionally, a lower head of the reactor pressure vessel may be removed in the refueling pool. In response to removing the lower head from the reactor pressure vessel, the method may comprise withdrawing the in-core instrumentation from the reactor core. A system for withdrawing in-core instrumentation from a reactor module is disclosed herein. The system may comprise means for performing a method similar to that described above. Various examples disclosed and/or referred to herein may be operated consistent with, or in conjunction with, one or more features found in U.S. Pat. No. 8,588,360, entitled Evacuated Containment Vessel for a Nuclear Reactor, U.S. Pat. No. 8,687,759, entitled Internal Dry Containment Vessel for a Nuclear Reactor, U.S. patent application Ser. No. 14/814,904, entitled Control Rod Position Indicator, and U.S. patent application Ser. No. 14/923,277, entitled Passive Cooling to Cold Shut-Down, the contents of which are incorporated by reference herein. FIG. 1 illustrates an example nuclear reactor module 100 with a dry and/or evacuated containment region 14. The nuclear reactor module 100 may comprise a reactor core 6 surrounded by a reactor pressure vessel 52. Primary coolant 10 in the reactor pressure vessel 52 surrounds the reactor core 6. Reactor pressure vessel 52 may be surrounded by a containment vessel 54. In some examples, containment vessel 54 may be located in a reactor pool 150. The reactor pool 150 may contain borated water stored below ground level. Containment vessel 54 may be at least partially submerged in the reactor pool 150. In some examples, at least a portion of the upper head of containment vessel 54 may be located above a surface 155 of the reactor pool 150 in order to keep any electrical connections and/or penetrations through the upper head dry. Additionally, containment vessel 54 may be configured to prohibit the release of any primary coolant 10 associated with reactor pressure vessel 52 to escape outside of containment vessel 54 into the reactor pool 150 and/or into the surrounding environment. Containment vessel 54 may be approximately cylindrical in shape. In some examples, containment vessel 54 may have one or more ellipsoidal, domed, or spherical ends, forming a capsule shaped containment. Containment vessel 54 may be welded or otherwise sealed to the environment, such that liquids and/or gases are not allowed to escape from, or enter into, containment vessel 54 during normal operation of reactor module 100. In various examples, reactor pressure vessel 52 and/or containment vessel 54 may be bottom supported, top supported, supported about its center, or any combination thereof. In some examples and/or modes of operation, an inner surface of reactor pressure vessel 52 may be exposed to a wet environment comprising the primary coolant 10 and/or vapor, and an outer surface of reactor pressure vessel 52 may be exposed to a substantially dry environment. The reactor pressure vessel 52 may comprise and/or be made of stainless steel, carbon steel, other types of materials or composites, or any combination thereof. The containment region formed within containment vessel 54 may substantially surround the reactor pressure vessel 52. Containment region 14 may comprise a dry, voided, evacuated, and/or gaseous environment in some examples and/or modes of operation. Containment region 14 may comprise an amount of air, a noble gas such as Argon, other types of gases, or any combination thereof. Additionally, the surfaces of one or both of reactor pressure vessel 52 and containment vessel 54 that bound containment region 14 may be exposed to water during certain modes of operation such as refueling, shutdown, or transport within the reactor pool 150. Containment region 14 may be maintained at or below atmospheric pressure, including a partial vacuum of approximately 300 mmHG absolute (5.8 psia) or less. In some examples, containment region 14 may be maintained at approximately 50 mmHG absolute (1 psia). In still other examples, containment region 14 may be maintained at a substantially complete vacuum. Any gas or gasses in containment vessel 54 may be evacuated and/or removed prior to operation of reactor module 100. During normal operation of reactor module 100, containment region 14 may be kept dry and/or evacuated of any water or liquid. Similarly, containment region 14 may be kept at least partially evacuated of any air or gases. A heat exchanger may be configured to circulate feedwater and/or steam in a secondary cooling system in order to generate electricity. In some examples, the feedwater passes through the heat exchanger and may become super-heated steam. The feedwater and/or steam in the secondary cooling system are kept isolated from the primary coolant 10 in the reactor pressure vessel 52, such that they are not allowed to mix or come into direct (e.g., fluid) contact with each other. The heat exchanger and/or associated piping of the secondary cooling system may be configured to penetrate through reactor pressure vessel 52 at one or more plenum 30. Additionally, the secondary piping may be routed to the upper region of containment above the level of the reactor pool 150, where the piping penetrates through containment vessel 54. By exiting containment above the reactor pool 150, the high temperature steam and feedwater lines do not loose heat to the reactor pool water 150. FIG. 2 illustrates the example nuclear reactor module 100 of FIG. 1, with a flooded or at least partially flooded containment region 14. During a normal, non-emergency shutdown, one or more steam generators may be configured to release steam and cool down the reactor module 100 from normal operating temperatures down to about 250° F. (121° C.). However, as the process of releasing steam may become somewhat ineffective at 250° F., the temperature of the reactor module may become essentially static or fixed the closer that it gets to the boiling temperature of the secondary coolant. The cool-down process may be augmented by at least partially flooding the containment region 14 of the example reactor module 100. In some examples, the containment region 14 may be flooded with borated water from the reactor pool 150 until the level of the water is at or above the height of a pressurizer baffle plate located within the reactor pressure vessel 52. During the cool-down process, water that enters containment region 14 is kept outside of reactor pressure vessel 52 and, similarly, all of the primary coolant 10 is kept within reactor pressure vessel 52. The upper head of the reactor pressure vessel 52 may be kept above the level of the water to avoid any connections that may pass through the upper head from being submerged in or otherwise exposed to water. In some examples, the predetermined level of the water within the containment region 14 may be associated with flooding the containment region 14 so that the majority of the reactor pressure vessel 52 is surrounded by the water. In other examples, the entire reactor pressure vessel 52 may be surrounded or submerged in the water that floods the containment region 14. The containment region 14 may be at least partially filled with water to initiate a passive cool-down process to a cold shutdown state, e.g., a shutdown state associated with primary coolant temperatures of less than 200° F. (93° C.). Once the containment region 14 is flooded above a predetermined level, no further action may be required, and the passive cool-down of the operating temperature to less than 200° F. may occur primarily as a function of natural circulation of the primary coolant 10 within the reactor pressure vessel 52, the shutdown reactor's decay heat, the transfer of heat from the primary coolant 10 to the water in the containment region 14, and the temperature of the reactor pool 150. During the cool-down process, an upper portion 16 of the containment region 14 may remain substantially dry and/or above the surface of the water contained therein. The pressure within upper portion 16 may be equalized to approximate atmospheric conditions as the reactor module reaches the shutdown state. A manway and/or release valve may be provided in the upper portion 16 of the containment region 14 to vent gases to atmosphere. In some examples, the manway and/or one or more valves may be configured to provide access to the containment region 14 for purposes of adding water. The pressure in the upper portion 16 may be controlled in order to maintain the level of water within the containment region 14 to a predetermined height within containment vessel 54. In examples where the reactor module 100 is configured to operate without any conventional thermal insulation being applied to the exterior of the reactor pressure vessel 52, heat may be readily transferred through the reactor vessel wall to the surrounding water in the containment region 14 during the cool-down process. FIG. 3 illustrates an example nuclear reactor module 300 comprising a reactor pressure vessel 320 housed within a partially disassembled containment vessel 340. A lower containment head 345 is shown removed from containment vessel 340. The removal of lower containment head 345 may be performed during refueling, maintenance, inspection, or other non-operational processes of reactor module 300. Containment vessel 340 may be removably attached to lower containment head 345 via an upper containment flange 342 and a lower containment flange 344. For example, a plurality of bolts may pass through and/or connect upper containment flange 342 to lower containment flange 344. Similarly, the bolts may be loosened and/or removed prior to removing lower containment head 345 from containment vessel 340. In-core instrumentation 330 is shown as being at least partially inserted into a reactor core 360 contained within reactor pressure vessel 320. In some examples, in-core instrumentation 330 may comprise twelve or more in-core instrument assemblies. Each in-core assembly may comprise a monitor, a sensor, a measuring device, a detector, other types of instruments, or any combination thereof. Additionally, the in-core assemblies may be attached to a number of wires or cables. The wires or cables associated with in-core instrumentation 330 may extend from an upper containment head 355 of containment vessel 340 down to reactor core 360. Upper containment head 355 may comprise one or more penetrations that are configured to allow in-core instrumentation 330 to be electrically coupled to wiring located outside of containment vessel 340. Lower containment head 345 may remain completely submerged below the surface 155 of a reactor pool, such as reactor pool 150 (FIG. 1) during the disassembly of containment vessel 340. While reactor pressure vessel 320 may remain intact and/or sealed during the disassembly of containment vessel 340, at least the lower portion of reactor pressure vessel 320 may also be surrounded by the reactor pool. FIG. 4 illustrates the example nuclear reactor module 300 of FIG. 3 comprising a partially disassembled reactor pressure vessel 320. A lower vessel head 325 is shown having been removed from the reactor pressure vessel 320, such as during refueling, maintenance, inspection, or other non-operational processes of reactor module 300. Reactor pressure vessel 320 may be removably attached to lower vessel head 325 via an upper vessel flange 322 and a lower vessel flange 324. For example, a plurality of bolts may pass through and/or connect upper vessel flange 322 to lower vessel flange 324. Similarly, the bolts may be loosened and/or removed prior to removing lower vessel head 325 from reactor pressure vessel 320. As a result of removing lower vessel head 325 from reactor pressure vessel 320, the in-core instrumentation 330 may be effectively withdrawn from the reactor core 360 as the lower vessel head 325 is being separated. Where in-core instrumentation 330 comprises multiple in-core instrument assemblies, all of the in-core instrument assemblies may be withdrawn from reactor core 360 substantially at the same time. In-core instrumentation 330 is shown as being at least partially protruding from or extending below the partially disassembled reactor pressure vessel 320 following the removal of lower vessel head 325. During a non-operational process, such as refueling, a visual inspection of the exterior of the reactor pressure vessel 320 and containment vessel 340 may be performed. Following the removal of lower containment head 345 and/or lower vessel head 325, remote inspection of the flanges and internal surfaces of the vessels may be performed while the vessels and/or lower heads are supported in one or more stands. In some examples, the remote inspections may comprise ultrasonic testing of key welds and full visual inspection of the internal surfaces. Additionally, some or all of the inspection may occur underneath the surface 155 of a reactor pool. In-core instrumentation 330 may remain connected to the top of containment vessel 340, and sealed by one or more pressurizer penetrations, as the reactor flanges are separated and lower vessel head 325 is removed from reactor pressure vessel 320. Each instrument assembly associated with in-core instrumentation 330 may be configured to slide out of their respective guide tubes in response to separating lower vessel head 325 from reactor pressure vessel 320. The withdrawal of in-core instrumentation 330 from the reactor core 360 and guide tubes may be accomplished without breaking the water-tight seal formed between containment vessel 340 and the surrounding pool of water. For example, the upper head of containment vessel 340 located at least partially above the surface 155 of the reactor pool may remain completely sealed to the surrounding environment during the disassembly of both the reactor pressure vessel 320 and the containment vessel 340, such that withdrawal of in-core instrumentation 330 from the guide tubes may be accomplished without providing any external access through the upper head of containment vessel 340. The guide tubes may be located in reactor core 360 and in some examples may extend up into a lower riser assembly 365 located above reactor core 360. In some examples, the in-core instrumentation 330 may be configured such that the lower ends are concurrently removed from both the lower riser assembly 365 and the reactor core 360 as a result of removing the lower head from the reactor pressure vessel 320. When in-core instrumentation 330 is clear of lower riser assembly 365, containment vessel 340 may be moved to a maintenance facility. On the other hand, lower vessel head 325 may be moved to a refueling bay, or remain behind without being moved, such that multiple operations may be performed on separated components of reactor module 300. During disassembly and transport of reactor module 300 and/or containment vessel 340, the lower ends of in-core instrumentation 330 may remain submerged in and surrounded by the reactor pool water at all times. The reactor pool water may operate to both reduce the temperature of in-core instrumentation 330 and provide a shield for any radiation which may be emitted from the lower ends. FIG. 5 illustrates a partial view of a nuclear reactor building 500 comprising equipment for assembling and/or disassembling a reactor module, such as reactor module 300 (FIG. 3). The equipment may comprise one or more stands located at the bottom of a containment pool or refueling bay. A first stand 510 may be configured to assemble and/or disassemble a containment vessel, such as containment vessel 340 (FIG. 3), after the reactor module has been shut down. During disassembly of the reactor module, a lower containment head 545 of the containment vessel may be placed in first stand 510. For example, a crane may be configured to transport the entire reactor module from a reactor bay and then lower the reactor module into first stand 510. After being placed in first stand 510, a containment flange associated with the lower containment head 545 may be de-tensioned by a containment tool 550, such as by loosening and/or removing a number of bolts. With lower containment head 545 decoupled from the containment vessel, the reactor module may be lifted from first stand 510 by the crane and placed in a second stand 520. With lower containment head 545 remaining behind in first stand 510, a lower vessel head 525 associated with a reactor pressure vessel may be placed in second stand 520. After being placed in second stand 520, a reactor vessel flange associated with lower vessel head 525 may be de-tensioned by a reactor pressure vessel tool 560, such as by loosening and/or removing a number of bolts. One or both of reactor pressure vessel tool 560 and containment tool 550 may be operated remotely. With lower vessel head 525 decoupled from the reactor pressure vessel, the reactor module may be lifted from second stand 520 by the crane and moved to a maintenance facility. Additionally, the lower vessel head 525 may be moved separately from the reactor module, or lower vessel head 525 may be refueled and/or maintenance work performed while being held in second stand 520. In some examples, the refueling bay containing reactor pressure vessel tool 560 and containment tool 550 may comprise a rectangular area approximately sixty feet long by thirty feet wide. The floor of the refueling bay may be at elevation twenty feet, and covered by seventy five feet of water. In some examples, the refueling bay floor may be approximately six feet below the bottom of pool for the balance of the facility. An inspection of the inner and outer surfaces of lower vessel head 525 and lower containment vessel 545 may be performed following the partial disassembly of the reactor module. Additionally, the exposed core support assembly and lower riser assembly may also be inspected. The inspection of the vessel features may include visual, volumetric, ultrasonic, and/or other inspection techniques. The inspections may be performed during the refueling process of the reactor module. A visual examination may be conducted to detect discontinuities and imperfections on the surface of components, including such conditions as cracks, wear, corrosion, or erosion. Additionally, the visual examination may be conducted to determine the general mechanical and structural condition of components and their supports by verifying parameters such as clearances, settings, and physical displacements, and to detect discontinuities and imperfections, such as loss of integrity at bolted or welded connections, loose or missing parts, debris, corrosion, wear, or erosion. A volumetric examination may indicate the presence of discontinuities throughout the volume of material and may be conducted from either the inside or outside surface of a component. The volumetric examination may comprise remotely deployed ultrasonic devices for examination of code identified vessel welds. A lower vessel inspection tree (LVIT) may comprise operating control console and cabling used to perform visual and ultrasonic testing of surfaces and features within lower vessel head 525 and lower containment vessel 545. An LVIT may be installed at or near the lower vessel sections in the bottom of the refueling pool. One or more LVITs may be used to locate, monitor, and report the position of inspection elements, and to acquire data that is transmitted back to the control console. The installation of the LVIT on the lower vessels may be performed remotely using a reactor building crane with the wet hoist attached. Additionally, in-pool cameras may be used by the crane operator to control crane motion and load placement. FIG. 6 illustrates a nuclear power building 600 comprising a plurality of reactor modules, such as a reactor module 610 and an additional reactor module 620. Nuclear power building 600 is shown as including twelve reactor modules by way of example only, and fewer or more reactor modules per nuclear power building are contemplated herein. Nuclear power building 600 may comprise an overhead crane 655 supported by a rail 695 and configured to move or transport the plurality of reactor modules. In the illustrated example, reactor module 610 has been removed from a reactor bay 630 and is in the process of being transported through a shared reactor building passageway 650. The passageway 650 may be fluidly connected to each of the reactor bays, such as reactor bay 630, allowing reactor module 610 to be transported by crane 655 while being at least partially submerged under water. Passageway 650 may fluidly connect reactor bay 630 to a spent fuel pool 680 and/or to a dry dock 690. Additionally, the passageway 650 may fluidly connect reactor bay 630 to a refueling bay 665 containing a containment vessel stand 660 and a reactor pressure vessel stand 670. In some examples, containment vessel stand 660 and reactor pressure vessel stand 670 may be configured similarly as first stand 510 and second stand 520 illustrated in FIG. 5, and may include a containment assembly/disassembly tool and a reactor pressure vessel assembly/disassembly tool, respectively. By including a plurality of reactor modules, reactor module 610 may be taken off-line for purposes of refueling and/or maintenance while the remaining reactor modules continue to operate and produce power. In a nuclear power facility comprising twelve reactor modules, where each reactor module has a designed fuel life of two years, a different reactor module may be refueled every two months as part of a continuous refueling cycle. For reactor modules having longer designed fuel lives, the reactor modules may be refueled less frequently. An LVIT 640 may be configured to enter nuclear power building 600 through an opening or door for purposes of conducting visual and/or ultrasonic inspections of the reactor modules. In some examples, LVIT 640 may be moved within nuclear power building 600 by crane 655. After the LVIT 640 has been placed by or near the vessel to be inspected, crane 655 may be disengaged from the LVIT 640, freeing crane 655 to perform other operations in support of the refueling outage while the inspections are conducted. Once the inspection is completed, crane 655 may be used to remove the LVIT 640 from the vessel that was inspected. LVIT 640 may be configured to inspect one or both of a reactor pressure vessel and a containment vessel. In some examples, two or more LVITs may operate concurrently to inspect the reactor pressure vessel and the containment vessel, providing the ability to perform multiple inspections at the same time. Providing duplicate and/or redundant inspection devices may reduce the amount of equipment necessary to complete the reactor module inspections, allow concurrent inspections of multiple reactor modules, and/or provide the ability to use either inspection device as a spare in the event of equipment failure. FIG. 7 illustrates an example nuclear reactor module 700 with at least a portion of the in-core instrumentation 730 withdrawn into a containment vessel 740. A lower containment head has been removed from containment vessel 740, such that a reactor pressure vessel 720 at least partially housed within containment vessel 740 may be accessed below a lower containment flange 742. Similarly, a lower vessel head has been removed from reactor pressure vessel 720 in the illustrated example. With both of the lower heads removed from reactor pressure vessel 720 and containment vessel 740, a lower reactor pressure vessel flange 722 may be located beneath a surface 755 of a pool of water. In other examples, both the lower reactor pressure vessel flange 722 and the lower containment flange 742 may be located beneath the surface 755. The surface 755 associated with the pool of water may be located within a dry dock, such as dry dock 690 (FIG. 6). In some examples, the level of surface 755 may be adjusted when the reactor module 700 is located at the dry dock in order to provide access to one or more components, such as a steam generator. In still other examples, the position of reactor module 700 may be lowered or raised to adjust the relative level of surface 755. In-core instrumentation 730 may be electrically coupled to an upper containment head 745 of containment vessel 740. A connection device 780 may provide a sealed penetration through upper containment head 745. External wiring 785 may be operably coupled to in-core instrumentation 730 via the connection device 780. In some examples, connection device 780 may comprise a two-part connector configured to attach to both in-core instrumentation 730 and external wiring 785. Additionally, in-core instrumentation 730 may be routed through a sealed penetration 760 of an upper head 725 of reactor pressurizer vessel 720. The withdrawal of in-core instrumentation 730 through sealed penetration 760 and into containment vessel 740 may operate to withdraw a lower end 735 of in-core instrumentation 730 into reactor pressure vessel 720. The withdrawal process may be initiated after the temperature of the reactor coolant and/or the reactor pressure vessel have decreased to a threshold cooling temperature, e.g., by the transfer of heat to the surrounding pool water. While the reactor coolant and/or the reactor pressure vessel are being cooled down, refueling and other maintenance operations may be performed on other components, such as the reactor core which has been separated from reactor pressure vessel 720. In some examples, such as where in-core instrumentation 730 comprises a plurality of in-core instrument assemblies, all of the lower ends 735 of the instrument assemblies may be withdrawn into reactor pressure vessel 720 at the same time. In other examples, each of the instrument assemblies may be separately withdrawn into reactor pressure vessel 720. An access portal 770 may be provided in upper containment head 745. Access portal 770 may be configured to provide access for an operator and/or a tool to enter containment vessel 740 for purposes of withdrawing in-core instrumentation 730. For example, the tool may comprise a pole and grasping device configured to attach to a portion of in-core instrumentation 730 located near or some distance above sealed penetration 760, in order to pull the portion of in-core instrumentation 730 into upper containment head 745. In other examples, the upper portion of in-core instrumentation 730 may be pulled up through a containment penetration provided at or near connection device 780, so that the upper portion of in-core instrumentation 730 may be pulled outside of containment vessel 740 without providing access through access portal 770. Sealed penetration 760 may comprise a Swagelok fitting. The fitting may be configured to retain the position of in-core instrumentation 730 at a fixed position. In some examples, sealed penetration 760 may be loosened to allow the withdrawal of the upper portion of in-core instrumentation 730 into containment vessel 740. Once the in-core instrumentation 730 has been withdrawn, sealed penetration 760 may be tightened to again fix the position of lower ends 735 within reactor pressure vessel 725. A Swagelok tool may be inserted into the upper containment head 745 of containment vessel 740 through access portal 770. In other examples, the sealed penetration 760 may be automatically loosened and tightened during different stages of the disassembly operation, without requiring access into the containment vessel 740. FIG. 8 illustrates an example an in-core instrumentation system 800 for a nuclear reactor. After performing a refueling operation and/or other maintenance activity, the reactor module may be prepared for reassembly of the reactor pressure vessel and containment vessel so that the reactor module may be placed back on line. For example, a lower head containing a reactor core with new fuel rods may be reattached to a reactor pressure vessel 820. Following the reattachment of the lower head to reactor pressure vessel 820, in-core instrumentation 830 may be reinserted into the replenished reactor core and/or into the corresponding guide tubes. In-core instrumentation 830 may comprise relatively flexible cabling suspended from a containment vessel connection 880. The instrumentation cabling may be routed through relatively rigid instrumentation sheathing 855. An upper end of instrumentation sheathing 855 may be supported by a bracket 850. Bracket 850 may be configured to stabilize the upper ends of sheathing 855 and, in some examples, may provide a means of simultaneously withdrawing in-core instrumentation 830 through an instrumentation position control device 860. Instrumentation position control device 860 may provide for a sealed penetration through an upper head of reactor vessel 820. Similar to the example nuclear reactor module 700 illustrated in FIG. 7, an upper portion of in-core instrumentation 830 may have been withdrawn into the containment vessel. The withdrawal of in-core instrumentation 830 may be accomplished by raising bracket 850. In some examples, the insertion of in-core instrumentation 830 into the reactor core and/or guide tubes may be accomplished by lowering bracket 850. In some examples, bracket 850 and/or instrumentation sheathing 855 may provide a guide by which in-core instrumentation 830 may be threaded or inserted down into the reactor core. Instrumentation sheathing 855 may comprise a threaded portion 835. The threaded portion 835 may be substantially the same length as the length of in-core instrumentation 830 that is withdrawn from reactor pressure vessel 820 into the containment vessel. Instrumentation position control device 860 may comprise one or more threaded gears and/or motors that may be configured to raise or lower in-core instrumentation 830 via a threaded engagement with the threaded portion 835 of instrumentation sheathing 855. Instrumentation position control device 860 may be remotely actuated to control the position of in-core instrumentation 830. Additionally, instrumentation position control device 860 may be remotely sealed or unsealed. FIG. 9 illustrates an example system 900 associated with withdrawing and/or inserting in-core instrumentation into a reactor core. A plurality of in-core instruments 930 may be connected to a containment vessel 940. In some examples, in-core instruments 930 may be suspended from an upper head of the containment vessel 940 at instrument connection 980. A reactor pressure vessel 920 may be at least partially located within the containment vessel 940. During full power operation of the reactor module, reactor pressure vessel 920 may be entirely housed in a sealed containment region within containment vessel 940. During the initial stages of a refueling operation, in which a lower head of containment vessel 940 may be removed in order to access the internal components of the reactor module including the reactor core 990, a portion of reactor pressure vessel 920 may be partially located outside of containment vessel 940. For example, a lower head of the reactor pressure vessel 920 may be exposed to a surrounding pool of water below the containment vessel 940. The reactor core 990 may be housed within a lower vessel head that is removably attached to the reactor pressure vessel 920. With the lower vessel head attached to the reactor pressure vessel 920, the lower ends of in-core instruments 930 may be located within the reactor core 990 which is housed in the lower vessel head of reactor pressure vessel 920. Additionally, in-core instruments 930 may pass through a vessel penetration 960 located in an upper vessel head of reactor pressure vessel 920. The in-core instruments 930 may be configured such that the lower ends are concurrently removed from the reactor core 990 as a result of removing the lower vessel head from the reactor pressure vessel 920. The lower ends of in-core instruments 930 may be removed from the reactor core 990 without unsealing the vessel penetration 960. Additionally, in examples in which the upper vessel head of the containment vessel 940 is environmentally sealed, the lower ends of in-core instruments 930 may be removed from the reactor core 930 without unsealing the upper vessel head of containment vessel 940. The containment vessel 940 may be at least partially submerged in a surrounding pool of water. As a result of removing the lower vessel head from the reactor pressure vessel 920, the lower ends of the in-core instruments 930 may be exposed to the pool of water. In examples where the lower vessel head is removably attached to the reactor pressure vessel 920 at a vessel flange, the exposed lower ends of the in-core instruments 930 may extend several meters below the vessel flange in the pool of water. The reactor module may be transported to a maintenance bay and/r refueling bay while the exposed lower ends of the in-core instruments 930 extend below the vessel flange into the pool of water. Additionally, an upper portion of the in-core instruments 930 may be withdrawn from the reactor pressure vessel 920 into the containment vessel 940 while the reactor pressure flange remains submerged in the pool of water. A reactor controller 970 may be configured to monitor the temperature of the in-core instruments 930. Reactor controller 970 may comprise a sensor, a gauge, a thermometer, a thermocouple, other means of monitoring temperature, or any combination thereof. Additionally, reactor controller 970 may be configured to monitor, measure, detect, read, sense, estimate, or otherwise determine the temperature associated with the reactor pressure vessel 920. Reactor controller 970 may be configured to raise and/or lower in-core instruments 930 in response to determining that the temperature associated with the in-core instruments 930 has reached a threshold cooling temperature. FIG. 10 illustrates an example process 1000 of refueling a nuclear reactor module. The reactor module may comprise a reactor vessel housed within a containment vessel. The containment vessel may at least partially surround the reactor pressure vessel by a containment region. The containment region may be evacuated of liquid and/or air during normal operation of the reactor module. Additionally, the containment vessel may be at least partially submerged in a reactor pool. At operation 1010, a reactor shut-down or other type of maintenance activity may be initiated. For example, a plurality of control rods may be inserted into the reactor core. At operation 1020, the sealed reactor module may be transported to a refueling pool. The reactor module may comprise a reactor pressure vessel housed within a containment vessel. In-core instrumentation may be at least partially located within the reactor core while the sealed reactor module is being transported. At operation 1030, a lower containment head of the containment vessel may be removed in the refueling pool. The lower containment head may be removed by placing the reactor module in a first stand and then loosening a plurality of bolts connecting the lower containment head to the containment vessel. The containment vessel may then be lifted off of the lower containment head while the lower containment head remains fixed in the first stand. At operation 1040, a lower head of the reactor pressure vessel may be removed in the refueling pool. The lower head of the reactor pressure vessel may be removed by placing the reactor module in a second stand and then loosening a plurality of bolts connecting the lower head of the reactor pressure vessel to the reactor pressure. The reactor pressure vessel may then be removed from the lower head while the lower head remains fixed in the second stand. The in-core instrumentation may be withdrawn from the reactor core together with, or as a result of removing, the lower vessel head from the reactor pressure vessel. In some examples, the in-core instrumentation is withdrawn from the reactor core after the lower vessel head is disconnected from a reactor pressure vessel flange. The in-core instrumentation may extend below the reactor pressure vessel flange in the refueling pool after the lower vessel head has been removed. At operation 1050, the temperature of the reactor coolant and/or the reactor pressure vessel may be allowed to cool down. During the cool down period, the reactor core may be separately processed for refueling. At operation 1060, at least a portion of the in-core instrumentation may be withdrawn from the reactor pressure vessel into the containment vessel after the lower head has been removed from the reactor pressure vessel. Operation 1060 may be performed in a maintenance facility, such as a maintenance bay. The maintenance bay may be fluidly connected to a refueling bay, such as by a shared waterway of a reactor building. At operation 1070, the reactor core may be refueled. In some examples, the reactor core may be refueled in the refueling bay while the portion of the in-core instrumentation is withdrawn from the reactor pressure vessel. Additionally, the reactor core may be refueled while the in reactor coolant and the reactor pressure vessel are allowed to cool down at operation 1050. At operation 1080, the lower head of the reactor pressure vessel may be reattached to the reactor module after the reactor core has been refueled. At operation 1090, the in-core instrumentation may be inserted into the replenished reactor core while returning the portion of the in-core instrumentation from the containment vessel back into the reactor pressure vessel. At operation 1110, the reactor module, with the in-core instruments having been inserted into the reactor core, may be transported to a reactor bay after the reactor module has been environmentally sealed by reattaching the lower containment head to the containment vessel. In other examples, the insertion of the in-core instrumentation at operation 1090 may occur after transporting the reactor module to the reactor bay at operation 1110. One or more example systems described herein may comprise various nuclear reactor technologies, and may comprise and/or be used in conjunction with nuclear reactors that employ uranium oxides, uranium hydrides, uranium nitrides, uranium carbides, mixed oxides, and/or other types of fuel. Although the examples provided herein have primarily described a pressurized water reactor and/or a light water reactor, it should be apparent to one skilled in the art that the examples may be applied to other types of power systems. For example, the examples or variations thereof may also be made operable with a boiling water reactor, sodium liquid metal reactor, gas cooled reactor, pebble-bed reactor, and/or other types of reactor designs. Additionally, the examples illustrated herein are not necessarily limited to any particular type of reactor cooling mechanism, nor to any particular type of fuel employed to produce heat within or associated with a nuclear reaction. Any rates and values described herein are provided by way of example only. Other rates and values may be determined through experimentation such as by construction of full scale or scaled models of a nuclear reactor system. Having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail. We claim all modifications and variations coming within the spirit and scope of the following claims. |
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abstract | It has been discovered that irradiating the cut side of sugarcane billets, preferably 2-50 mm, with UVB or UVC light or combinations thereof initiates stilbene production, particularly resveratrol and piceatannol. In an embodiment the cut sides of sugarcane billets of a predetermined thickness are irradiated with Ultraviolet-C or Ultraviolet-B light or combinations thereof at an intensity and for a duration of time sufficient to produce a significant increase in a level of one or more stilbenes in the irradiated billets compared to a level of stilbenes in billets that are not irradiated; and the irradiated sugarcane billets are maintained for at least about three days up to about 20 days, to optimize stilbene levels. |
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048636800 | claims | 1. A fuel assembly having a plurality of cylindrical fuel rods having a plurality of fuel pellets sealed therein and a channel box for holding said cylindrical fuel rods in a regularly bundled pattern, comprising; a plurality of small units each having a predetermined number of said fuel rods bundled as spaced with a fixed intercentral distance and being arranged in such a manner that the intercentral distance between the component fuel rods falling on the mutually juxtaposed sides of the adjacent small units is larger than the intercentral distance between the adjacent fuel rods in the same units; and at least one water rod disposed near the center of a cluster of said plurality of units. a plurality of small units each having a predetermined number of fuel rods bundled as spaced with a fixed intercentral distance and being arranged in such a manner that the intercentral distance between the component fuel rods falling on the mutually juxtaposed sides of the adjacent small units is larger than the intercentral distance between the adjacent fuel rods in the same units; at least one water rod disposed among said plurality of small units; and at least either of an internal gap formed consequently among said small units and said water rod allowed to be disposed as deviated from the center of an in-channel toward a narrow gap side. 2. The fuel assembly of claim 1, wherein at least one of the fuel rods located near each of the peripheral corners is a partial length fuel rod. 3. The fuel assembly of claim 1, wherein the intercentral distance between the fuel rods belonging one each to two adjacent small units is varied by the combination of small units. 4. A fuel assembly intended for incorporation in a D-lattice core having a plurality of cylindrical fuel rods with a plurality of fuel pellets sealed therein and a channel box containing said cylindrical fuel rods in a regularly bundled pattern, comprising: 5. The fuel assembly of claim 4, wherein said internal gap is in the shape of four sides of a square each extended outwardly slightly from the corners of said square and a greater width is given to the narrow gap side gaps then to the wide gap side gaps of said internal gap. |
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056595913 | claims | 1. In a light-water reactor having a safety tank defining a containment, a containment spray system, comprising: a water trough being disposed in the safety tank and having a bottom; and an immersion pump disposed in the vicinity of said bottom of said water trough, a spray branch and an outlet-side spray nozzle array, connected to said water trough for injecting water into the containment in finely dispersed form in the event of an operational incident. 2. The containment spray system according to claim 1, wherein said water trough is a fuel assembly storage trough being unused and decoupled from a reactor sump circuit during normal operation. 3. The containment spray system according to claim 2, wherein said fuel assembly storage trough is filled with borated water. 4. The containment spray system according to claim 2, wherein said fuel assembly storage trough is an inner storage trough disposed toward a reactor pressure vessel. 5. The containment spray system according to claim 2, wherein said fuel assembly storage trough has a cover forming a protection against rubble. 6. The containment spray system according to claim 1, wherein said spray nozzles have a bore diameter and said immersion pump has a feed pressure, being adjusted for producing a maximum droplet diameter of 100 .mu.m in a spray mist. 7. The containment spray system according to claim 6, wherein said bore diameter is in a range between 0.5 mm and 1 mm and said feed pressure of said immersion pump is between approximately 3 bar and 80 bar. 8. The containment spray system according to claim 6, wherein said bore diameter is in a range between 1 mm and 1.5 mm and said feed pressure of said immersion pump is between approximately 6 bar and 80 bar. |
abstract | Disclosed herein is a method comprising heating helium in a core of a nuclear reactor; extracting heat from the helium; superheating water to steam using the heat extracted from the helium; expanding the helium in a turbine; wherein the turbine is in operative communication with an electrical generator; and generating electricity in the electrical generator. |
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summary | ||
description | The present application claims priority from Japanese application serial no. 2006-050916, filed on Feb. 27, 2006, the content of which is hereby incorporated by reference into this application. The present invention relates to a reactor power control apparatus, and more particularly to a reactor power control apparatus of a natural circulation reactor in which coolant is circulated by natural circulation. In addition, the present invention relates to a natural circulation reactor generation system of which includes the reactor power control apparatus. The present invention relates further to a method for controlling reactor power of a natural circulation reactor. Generally, reactors are largely divided into a forced circulation type and a natural circulation type based on a circulation system of the coolant (cooling water) . The forced circulation reactor includes a recirculation pump such as a jet pump or an internal pump or the like. This pump supplies forcibly cooling water into the core. Meanwhile, the natural circulation reactor does not include a recirculation pump as in the case of the forced circulation reactor. The cooling water is circulated by the natural circulation force which is based on the difference in density of the cooling water outside of a core shroud which surrounds a core and two-phase flow including steam and cooling water inside the reactor shroud. In this manner, because the natural circulation reactor does not include a recirculation pump, when load variation of the reactor is demanded, it necessary to be changed the reactor power by operation of a control rod. However, in the case where control rod operation is used, there is a problem in that because the time constant is large from the operation of the control rod to when power of a generator or the like is changed, the following for the load variation becomes bad. A natural circulation reactor in which thermal power of the reactor is changed without control rod operation is known (see Japanese Patent No. 2521256). Reactor power is changed by using a turbine steam (main steam) control valve and a turbine bypass valve in tandem to control thermal power from the reactor (see Japanese Patent No. 2521256). The natural circulation reactor disclosed in Japanese Patent No. 2521256 achieves the decrease of the generator power, in other words, the decrease of the reactor power by opening the turbine bypass valve and introducing steam to a condenser. Also, the increase of the generator power, that is, the increase of the reactor power is achieved by increasing reactor pressure and collapsing void in the cooling water due to close of the turbine steam control valve. However, in the case where the turbine steam control valve is closed and the reactor pressure is increased, because the flow rate of steam being supplied to the turbine is reduced, there is a problem in that the generator power is decreased and the reactor power is changed. The object of the present invention provides a reactor power control apparatus of a natural circulation reactor which can suppress generator power variation and supply stable electrical power and also suppress variation in the reactor power. In order to accomplish the object of the present invention described above, the present invention is a reactor power control apparatus of a natural circulation reactor comprising: a reactor power control section for controlling reactor power; and a pressure control section for controlling reactor pressure, wherein the degree of the opening of a inlet port steam control valve provided with a moisture separation heater is controlled based on a power adjustment demand signal being input from the power control section into the pressure control section. As a result, when load change is demanded for the reactor, by controlling the opening and closing of the inlet port steam control valve, the flow rate of steam passing the inlet port steam control valve is adjusted and variation in the reactor power is suppressed. According to the power control apparatus of a natural circulation reactor of the present invention, stable reactor power can be obtained without great variation in reactor power. In addition, following of load variation is improved. According to the generation system of the natural circulation reactor of the present invention, stable generator power can be obtained without great variation in reactor power. Furthermore, according to the power control method for the natural-circulation reactor of the present invention, stable reactor power can be obtained without great variation in reactor power. Preferred embodiments of a reactor power control apparatus of a natural circulation reactor according to the present invention will be described with reference to the drawings, but the present invention is not to be limited by the following examples. FIG. 1 is a pattern diagram showing an embodiment of the generation system having the reactor power control apparatus of the natural circulation reactor of the present invention. As shown in FIG. 1, the natural circulation reactor included in the generation system of the natural circulation reactor comprises a plurality of fuel assemblies 1 and a reactor pressure vessel 6 which encloses a core 4 wherein a control rod 3 is inserted into a space between the fuel assemblies 1 to control the reactivity of the core 4. Control rod drive apparatuses 8 are provided at the lower part of the reactor pressure vessel 6. The control rod drive apparatuses 8 drive the control rod 3 in the vertical direction inside the core 4 such that it can be inserted and withdrawn. The main steam pipe 32 and the feed water pipe 33 are connected to the reactor pressure vessel 6. A cylindrical core shroud 5 is disposed so as to enclose the core 4. An ascending path in which the coolant ascends in the direction of the arrow in the drawing is formed in the core shroud 5. A downcomer 7 which is descending paths is formed between the core shroud 5 and the reactor pressure vessel 6. The coolant descends in the downcomer 7. A cylindrical chimney 9 is disposed at the upper section of the core shroud 5 and a steam separator 10 and a steam dryer 11 are provided at the upper side of the chimney 9. The coolant undergoes natural circulation force due to the difference in density between the coolant that is the two phase gas-liquid, boiled in the core 4 and ascending in the chimney 9 and the coolant that is liquid phase, descending in the downcomer 7. In the reactor pressure vessel 6, a circulation path that the coolant descends down the downcomer 7 and then ascends in the core 4 and the chimney 9, and the coolant separated the steam by the steam separator 10 descends in the downcomer 7 another time, is formed. At the steam drier 11, the tiny water droplets are removed from the steam that is separated at the steam-water separator 10, and then the steam is supplied to the high-pressure turbine 17 and then introduced to the low-pressure turbine 18 via the main steam pipe 32. The steam introduced to the low-pressure turbine 18 is converted to rotational energy for the turbine. A generator 21 connected to the low-pressure turbine 18 is rotated and the power is generated. In addition a moisture separation heater 22 for heating the steam whose temperature was reduced in the high-pressure turbine 17 and restoring energy efficiency is provided between the high-pressure turbine 17 and the low-pressure turbine 18. The steam that rotated the low-pressure turbine 18 is condensed at the condenser 23 which has a cooling source and the steam becomes condensed water (cooling water). The condensed water is passed through the feed water pipe 33 having the feed water pump 24 and returned to the inside of the reactor pressure vessel 6. It is to be noted that the main steam pipe 32 has a main steam control valve 28 for adjusting the flow rate of steam being supplying into the high-pressure turbine 17. The inlet port steam pipe 29 and the turbine bypass pipe 30 are also connected to the main steam pipe 32. The inlet port steam pipe 29 has an inlet port steam control valve 27 which adjusts the amount of steam flowing into the moisture separation heater 22. The turbine bypass pipe 30 has a turbine bypass valve 31 which adjusts the flow rate of steam being introduced to the condenser 23. The reactor power control apparatus of the natural-circulation reactor provides with a power control apparatus 15 which is the power control section for controlling the reactor power to a predetermined reactor power and a pressure control apparatus 16 which is the power control section for controlling the reactor pressure to a predetermined pressure. The load following demand signal S2 from the center feeding chamber (not shown), the power adjustment demand signal S4 from the power control apparatus 15 and the reactor pressure signal S9 from the reactor pressure detector 13 provided in the reactor pressure vessel 6 are input to the pressure control apparatus 16. It is to be noted that any one of the load following demand signal S2 and the power adjustment demand signal S4 may be input. The load following demand signal S2 herein may, for example, be a signal having comparatively narrow range and short period which is output from the center feeding chamber for stabilizing the overall generation power of the generation system, and refers to a sign wave type signal which changes in units of seconds as is the case for speed governing. Inlet port steam control valve opening command signal S8 for the inlet port steam control valve 27, main steam control valve opening command signal S5 for the main steam control valve 28 and turbine bypass valve opening command signal S7 for the turbine bypass valve 31 are output from the pressure control apparatus 16. Further, the reactor power equivalent signal S20 to be input to the power control apparatus 15 is output from the pressure control apparatus 16. The reactor power signal S1 from the reactor power detector 12 provided in the reactor pressure vessel 6 and the abovementioned reactor power equivalent signal S20 are input into the power control apparatus 15. The abovementioned power adjustment demand signal S4 and the control rod drive command signal S21 for the control rod drive control apparatus 14 are output from the power control apparatus 15. The power control apparatus 15 into which the reactor power equivalent signal S20 has been input, outputs the control rod drive command signal S21. The control rod drive control apparatus 14 is driven by the control rod drive command signal S21. In the case where the reactor power equivalent signal S20 is the command signal that increases the reactor power, the control rod 3 is withdrawn from the core 4 by the control rod drive apparatus 8. In the case where the reactor power equivalent signal S20 is the command signal that decreases the reactor power, the control rod 3 is inserted into the core 4. FIG. 2 shows control system inside the pressure control apparatus 16 in the generation system of the natural circulation reactor shown in FIG. 1. As shown in FIG. 2, in the pressure control apparatus 16, the power adjustment demand signal S4 which is the error signal in which the current power value is subtracted from the target power value, is output from the power control apparatus 15 and input into the power controller 163 which is provided in the pressure control apparatus 16. It is to be noted that the power adjustment demand signal S4 may be directly input into the power controller 163 without going via the power control apparatus 15. Preset pressure setting value for keeping the reactor pressure fixed is subtracted from reactor pressure signal S9 output from the reactor pressure detector 13. Pressure error signal S11 that is the error between the preset pressure setting value and the reactor pressure signal S9 is input to the pressure adjuster 161 provided in the pressure control apparatus 16. The pressure adjuster 161 adjusts the input pressure error signal S11 and outputs the pressure signal S12. The low value preferential signal S15 output from the low value preferential circuit 164 as described hereinafter is subtracted from the pressure signal 12. As a result, turbine bypass valve opening command signal S7 that is error signal is generated. The turbine bypass valve 31 is opened based on the difference amount of the turbine bypass valve opening command signal S7. The pressure signal S12 output from the pressure adjuster 161, the turbine speed control signal S14 that is output from the turbine speed controller and the load limit signal S13 output from the load limiter 162 that is provided in the pressure control apparatus 16 are input into low value preferential circuit 164. The low value preferential circuit 164 selects one low value signal of the pressure signal S12, the load limit signal S13 and the turbine speed control signal S14, and outputs the low value preferential signal S15. In the case where the reactor power decreases, the power controller 163 performs proportional-integral control to the input power adjustment demand signal S4, and outputs inlet port steam control valve opening command signal S8 which is the close command. The inlet port steam control valve 27 is closed based on the inlet port steam control valve opening command signal S8 and as a result, reactor power increases. It is to be noted that the signal being input into the power controller 163 may also be the load following demand signal S2 output from the center feeding chamber. In the case where the load following demand signal S2 is the generator power increase request signal, as described above, the inlet port steam control valve 27 is closed based on the inlet port steam control valve opening command signal S8 and reactor power increases. Meanwhile, the power control signal S16 output from the power controller 163 is added to the low-value preferential signal S15, and the main steam control valve opening command signal S5 is generated. The main steam control valve 28 is opened based on the addition amount of the main steam control valve opening command signal S5. As described above, in the reactor power control apparatus of this embodiment, when the inlet port steam control valve opening command signal S8 is output as a close command, the degree of opening of the inlet port steam control valve 27 is controlled to be 0%, in other words, the inlet port steam control valve is closed. Thus, the steam that is to be supplied to the inlet port steam pipe 29 is blocked by the inlet port steam control valve 27 and introduced into the main steam control valve 28. As a result, the flow rate of steam being supplying to the high-pressure turbine 17 increases and power of the generator 21, that is, the reactor power can be increased. In this manner, according to the reactor power control apparatus of this embodiment, because power from the generator 21 can be increased in a short period of time without operating the control rod 3, following of load variation can be increased. In addition, according to the reactor power control apparatus of the natural circulation reactor of this embodiment, even if there is variation in reactor power, the main steam control valve 28 through which an abundance of steam pass is never closed. Thus, operation of the reactor can continue without causing any variation in reactor power. According to the power control method for the natural circulation reactor of this embodiment, stable reactor operation can be performed without great variation in reactor power, because firstly, continuous valve open and close control of a series of valves described above is performed by the pressure control apparatus 16 in a short period, and subsequently long control operations such as that required for control rod 3 operation is performed by the power control apparatus 15 as described above. In addition, as shown in FIG. 7, the control being performed in the reactor power control apparatus of this embodiment is performed for load variation which occurs mainly during rated power operation and not during start-up operation. That is to say, in the reactor power control apparatus of this embodiment, control carried out in a comparatively short period of time is performed by the pressure control apparatus 16, and control which requires a comparatively long period of time is performed by the power control apparatus 15. It is to be noted that in this embodiment, the degree of valve opening of the inlet port steam control valve 27 is either 0% or 100% which is the fully open operation state, but a structure having the half open configuration such as that in which the degree of valve opening of the inlet port steam control valve 27 is about 50% may be employed. Because the degree of the opening of the inlet port steam control valve 27 is in the half open state in this manner, the degree of the valve opening has the margin. Thus, the inlet port steam control valve can be operated when the reactor power increases, as well as when the reactor power decreases. FIG. 3 shows a control system of another embodiment of the pressure control apparatus 16 in the reactor generation system shown in FIG. 1. The structure of this embodiment differing from the control system shown in FIG. 2 will be described hereinafter. The power controller 163 outputs power control signal S17 obtained by subjecting to proportional-integral control the power adjustment demand signal S4 for example. This power control signal S17 is added to the differential signal S18 obtained by subtracting the low value preferential signal S15 from the power signal S12. The turbine bypass valve opening command signal S7 is obtained by adding the power control signal S17 to the differential signal S18. The degree of the opening of the turbine bypass valve 31 is controlled based on the addition amount of this turbine bypass valve opening command signal S7. According to the reactor power control apparatus of this embodiment, because the steam of the amount which is proportional to the degree of the opening of the turbine bypass valve 31 is supplied to the condenser 23 and the steam becomes condensed water, power of the generator 21, in other words, the reactor power can be maintained at a constant value. Thus, the reactor power control apparatus of this embodiment is effective as a control system in the case where the reactor power varies. It is to be noted that two power control signals S16 and S17 may be output from the power controller 163, and open and close control of the main steam control valve 28 and open and close control of the turbine bypass valve 31 may be performed together. As a result, both the main steam control valve 28 and the turbine bypass valve 31 are used together and reactor power can be adjusted. FIG. 4 shows a control system of another embodiment in the pressure control apparatus 16 in the reactor generation system shown in FIG. 1. In the control system of this embodiment, the structure differing from the control system shown in FIG. 2 will be described hereinafter. This pressure control apparatus provides with an input gate portion 160 that inputs the output power adjustment demand signal S4. In the case where the reactor power state is greater than the target value, the value of the power adjustment demand signal S4 is defined as negative, and in the case where the reactor power state is smaller than the target value, the value of the power adjustment demand signal S4 is defined as positive. That is to say, in the case where the input power adjustment demand signal S4 is negative, the reactor power is controlled so as to decrease. In the case where the input power adjustment demand signal S4 is positive, the reactor power is controlled so as to increase. As shown in FIG. 5, in this embodiment, in the case where the threshold value is set at 0 and the power adjustment demand signal S4 is a negative signal, an upper limit that is less than 0 is set. In the case where the power adjustment demand signal S4 is a positive signal, a lower limit that is greater than 0 is set. As a result, the turbine bypass valve 31 and the inlet port steam control valve 27 are controlled separately. In the case where the input power adjustment demand signal S4 is negative, the power adjustment demand signal S4 passed through the input gate portion 160 is changed the sign and is subsequently input into the power controller 163a provided in the pressure control apparatus 16. The power controller 163a performs the proportional-integral control to the input power adjustment demand signal S4 for example, and outputs power control signal S16. The power control signal S16 is added to the differential signal S18 obtained by subtracting the low value preferential signal S15 from the power signal S12 to become the turbine bypass valve opening command signal S7. As a result, the opening of the turbine bypass valve 31 is controlled by the addition amount of this turbine bypass valve opening command signal S7. Thus, according to reactor power control apparatus of this embodiment, in the case where the power adjustment demand signal S4 is negative, because the steam of the amount which is proportional to the degree of the opening of the turbine bypass valve 31 is supplied to the steam condenser 23 and the steam becomes condensed water, the power of the generator 21, in other words, the reactor power that has been increased for some reason is controlled so as to decrease (or return to the target value). Meanwhile, in the case where the input power adjustment demand signal S4 is positive, the power adjustment demand signal S4 is passed through the input gate portion 160 and then input into the power controller 163b provided in the pressure control apparatus 16. The power controller 163b performs the proportional-integral control for the power adjustment demand signal S4 for example, and outputs the inlet port steam control valve opening command signal S8 which is the close command. The inlet port steam control valve 27 is controlled so as to close by this inlet port steam control valve opening command signal S8. Thus, according to the reactor power control apparatus of this embodiment, in the case where the power adjustment demand signal S4 is positive, the degree of the opening of the inlet port steam control valve 27 is controlled to be 0%, that is, such that the inlet port steam control valve 27 is closed. Accordingly, the steam flow being introduced to the inlet port steam pipe 29 is stopped by the inlet port steam control valve 27. As a result, the reactor power that has decreased for some reason can be increased (returned to the target value). In this manner, according to the reactor power control apparatus of this embodiment, because the reactor power can be adjusted (restored to the target value) in a short period of time without operating the control rod, continuous operation of the reactor with stable reactor power becomes possible. It is to be noted that the signal being input can be the load following demand signal S2 that was output from the power control apparatus 15 rather than the power adjustment demand signal S4. It is to be noted that in this case, it is preferable that the power control signal S16 from the power controller 163a corrects the main steam control valve opening command signal S5 and the degree of the opening of the main steam control valve 28 is adjusted by the corrected main steam control valve opening command signal S5. The following is a description of the state of the natural circulation reactor in the case where the reactor power control apparatus of this invention is used. FIG. 6 shows the relative changes of the main parameters for the state of the natural circulation reactor in which the reactor power control apparatus is used. As shown in FIG. 6, reactor neutron flux, reactor pressure, and the degree of the opening of the inlet port main steam control valve (MSH-CV) are selected as the main parameters. The relative changes in the main parameter are described in a time series. First, for example reduction of the neutron flux in the reactor pressure vessel 6 begins and reduction of the reactor power begins due to variation in the feed water temperature by a change in the operation state of the feed water pump changing for some reason (A). When this occurs, the degree of the opening of the inlet port steam control valve 27 is controlled so as to be smaller by the pressure control apparatus 16 which receives the power adjustment demand signal S4 (B). Next, the internal pressure of the reactor pressure vessel 6 starts to increase when the inlet port steam control valve 27 closes (C). In addition, when the internal pressure of the reactor pressure vessel increases, the void that is generated in the reactor is collapsed, and thus neutron flux increases and reactor power is restored (D). Furthermore, because the control rod 3 is withdrawn from the core 4 by the power control apparatus 15 that input the reactor power equivalent signal S20, the neutron flux in the reactor is gently increased and the reactor power also gently increase so as to correspond with the neutron flux increase (E) In addition, as the reactor power is restored, the degree of the opening in the inlet port steam control valve 27 is also restored to its original state (F). It is to be noted that the reactor power control apparatus of the present invention is not to be limited by the embodiments described above and as a matter of course, various modifications and changes can be made to the structure of the present invention in terms of use of other materials and configuration, without departing from the scope of the present invention. |
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052951650 | abstract | Self-locking plug for plugging a hole defined by a surrounding structure, which structure may be a nuclear power reactor pressure vessel core barrel flange. When the hole is plugged, transient hydraulic forces generated in the pressure vessel will tend to force the plug from the hole. The plug includes a plug body sized to be disposed in the hole and a locking member pivotally connected to the plug for locking the plug body to the flange, so that the plug is not inadvertently forced from the hole by the transient hydraulic forces. A cam, which is capable of engaging the locking mechanism for outwardly pivoting the locking mechanism, is slidably connected to the plug body. A movable piston is connected to the cam for driving the cam into engagement with the locking mechanism. Moreover, the locking mechanism pivots to engage the flange as the cam engages the locking member. A ram, which is also connected to the plug body, is provided to ram the plug body into the hole for snugly plugging the hole. In this manner, the plug is locked to the flange and resists being inadvertently dislodged from the hole, which may otherwise occur due to transient hydraulic forces generated in the pressure vessel during service operations to retrieve the detector. |
043269184 | summary | The present invention relates generally to the storage of spent nuclear fuel and more particularly to a low cost, uncomplicated and yet reliable technique for storing spent nuclear fuel safely. The problem with storing spent (actually partially spent) nuclear fuel is not a new one. Delays in reprocessing have resulted in a particular need for interim storage capability for the spent fuel. Many conventional options exist such as storage pools at or away from reactor sites. However, their implementation is characterized by high cost, long lead times and/or other logistic limitations such as shipping cask availability. As will be seen hereinafter, the present invention eliminates or at least minimizes these constraints by permitting on site or at least localized storage at a relatively low cost using readily available materials. In view of the foregoing, an object of the present invention is to provide an uncomplicated, economical and yet reliable and safe technique for storing spent fuel from a nuclear reactor. Another object of the present invention is to provide a nuclear fuel storage technique which utilizes readily available components. A more specific object of the present invention is to provide an assembly for storing spent fuel, which assembly has a predesigned cooling capability while, at the same time, automatically compensating for a malfunction in this capability. Another more specific object of the present invention is to provide a fuel storage assembly which utilizes the same means for protecting the assembly against cooling malfunction while, at the same time, serving as a heat transfer media, a neutronic poison and as an absorber/combining agent for any non-gaseous material inadvertently released from the contained fuel rods. As will be described in more detail hereinafter, the storage assembly disclosed herein is one which has housing means adapted for positioning underground and including a closed inner chamber for containing the nuclear fuel, e.g., the fuel rods. A thermally conductive member is located partially within the inner chamber and partially outside the housing means for transferring heat generated by the contained nuclear fuel from the housing chamber to the surrounding ground. In accordance with the present invention, particulate material is located within the chamber and around the nuclear fuel contained therein. This material is seclected so as to serve as a heat transfer media between the contained nuclear fuel and the heat transferring member while, at the same time, standing ready to fuse into a solid mass around the contained nuclear fuel if the heat transferring rod malfunctions or otherwise fails to transfer the heat generated by the fuel out of the chamber in a predetermined manner. |
description | The present invention relates to a technique for a structure of a radiation detection apparatus used in a radiation tomography apparatus. In a conventional radiation detection apparatus in a radiation tomography apparatus, a collimator and a detector element array are generally attached to each other as individual components (for example, see Abstract in Patent Document 1 and the like). However, since in recent years coverage in a slice direction is extended, and the collimator arcuately arranged facing a radiation source may lead to better control of image quality degradation, a construction having the collimator integrated with the detector element array is becoming mainstream. In such a construction, the collimator and detector element array are generally adhesively secured by an adhesive. The collimator, however, is constructed of heavy metal such as tungsten, and therefore, it experiences a large centrifugal force by a rotation during a scan. Moreover, the collimator and detector elements have significantly different coefficients of linear expansion, so that their adhesive layer suffers from stress due to a change in ambient temperature. These phenomena may induce a failure in the adhesive layer with time, which causes the collimator to fall off. In view of such circumstances, there is a need for a technique for preventing a collimator from falling off from a radiation detection apparatus even when a failure of the adhesive joint occurs in the collimator. The invention in its first aspect provides a radiation detection apparatus for use in a radiation tomography apparatus, said radiation detection apparatus comprising: a detector element array in which a plurality of detector elements are arranged substantially in a fan-angle direction and in a cone-angle direction of a radiation; a collimator adhesively bonded to a side of said detector element array on which the radiation impinges, and having outer end surfaces on both sides in the cone-angle direction tapered to align with a direction of emission from a radiation source; and a pair of blocks disposed to sandwich said collimator in the cone-angle direction, and having inner end surfaces on both sides in the cone-angle direction tapered to align with said direction of emission. The invention in its second aspect provides the radiation detection apparatus in the aforementioned first aspect, wherein: said outer end surface in said collimator on either side lies close to said inner end surface in said pair of blocks on either side and separated by a space. The invention in its third aspect provides the radiation detection apparatus in the aforementioned first aspect, wherein: said outer end surface in said collimator on either side is adjacent to said inner end surface in said pair of blocks on either side with an elastic material interposed therebetween. The invention in its fourth aspect provides the radiation detection apparatus in any one of the aforementioned first through third aspects, wherein: said collimator comprises a plurality of collimator modules arranged in the fan-angle direction, and each of said plurality of collimator modules has both end surfaces in the cone-angle direction tapered to align with said direction of emission. The invention in its fifth aspect provides the radiation detection apparatus in any one of the aforementioned first through fourth aspects, wherein: said collimator comprises a plurality of collimator modules arranged in the cone-angle direction, and each of said plurality of collimator modules has both end surfaces in the cone-angle direction tapered to align with said direction of emission. The invention in its sixth aspect provides a radiation detection apparatus for use in a radiation tomography apparatus, said radiation detection apparatus comprising: a detector element array in which a plurality of detector elements are arranged substantially in a fan-angle direction and in a cone-angle direction of a radiation; a collimator adhesively bonded to a side of said detector element array on which the radiation impinges, and having outer end surfaces on both sides in the fan-angle direction tapered to align with a direction of emission from a radiation source; and a pair of blocks disposed to sandwich said collimator in the fan-angle direction, and having inner end surfaces on both sides in the fan-angle direction tapered to align with said direction of emission. The invention in its seventh aspect provides the radiation detection apparatus in the aforementioned sixth aspect, wherein: said outer end surface in said collimator on either side lies close to said inner end surface in said pair of blocks on either side and separated by a space. The invention in its eighth aspect provides the radiation detection apparatus in the aforementioned sixth aspect, wherein: said outer end surface in said collimator on either side is adjacent to said inner end surface in said pair of blocks on either side with an elastic material interposed therebetween. The invention in its ninth aspect provides the radiation detection apparatus in any one of the aforementioned sixth through eighth aspects, wherein: said collimator comprises a plurality of collimator modules arranged in the fan-angle direction, and each of said plurality of collimator modules has both end surfaces in the fan-angle direction tapered to align with said direction of emission. The invention in its tenth aspect provides the radiation detection apparatus in any one of the aforementioned first through ninth aspects, wherein: said pair of blocks are included in a support portion for directly or indirectly supporting said detector element array. The invention in its eleventh aspect provides a radiation tomography apparatus comprising the radiation detection apparatus in any one of the aforementioned first through tenth aspects. According to the invention in the aspects described above, the radiation detection apparatus comprises a collimator having outer end surfaces on both sides in a specified direction tapered, the direction being a fan-angle direction or a cone-angle direction, and a pair of blocks disposed to sandwich the aforementioned collimator in the aforementioned specified direction, and having inner end surfaces on both sides in the aforementioned specified direction tapered; thus, even in case that adhesive delamination occurs between the collimator and detector element array, the collimator can be prevented from falling off to the outside of the aforementioned blocks by a what-is-called wedge effect. FIG. 1 is a diagram schematically showing a configuration of an X-ray CT (Computed Tomography) apparatus (radiation tomography apparatus) in accordance with a first embodiment. As shown in FIG. 1, the X-ray CT apparatus 100 comprises an operation console 1, an imaging table 10, and a scan gantry 20. The operation console 1 comprises an input device 2 for accepting an input from an operator 41, a data processing apparatus 3 for controlling several sections for imaging of a subject (object to be imaged) 40 and applying data processing for producing an image, etc., a data collection buffer 5 for collecting data acquired in the scan gantry 20, a monitor 6 for displaying an image, and a storage device 7 for storing therein programs, data, and the like. The imaging table 10 comprises a cradle 12 for laying thereon the subject 40 to carry the subject 40 into a bore B in the scan gantry 20. The cradle 12 is vertically and horizontally translated by a motor incorporated in the imaging table 10. As used herein, a body axis direction of the subject 40, i.e., a direction of horizontal translation of the cradle 12, will be referred to as z-axis direction, a vertical direction as y-axis direction, and a horizontal direction perpendicular to the z- and y-axis directions as x-axis direction. The scan gantry 20 comprises a rotatably supported rotating section 15. The rotating section 15 is provided with an X-ray tube 21, an X-ray controller 22 for controlling the X-ray tube 21, an aperture 23 for shaping X-rays 81 generated from the X-ray tube 21 into a fan beam or a cone beam, an X-ray detector (radiation detection apparatus) 24 for detecting the X-rays 81 passing through the subject 40, a DAS 25 for collecting output signals from the X-ray detector 24 as data, and a rotating section controller 26 for controlling the X-ray controller 22 and aperture 23. The body of the scan gantry 20 comprises a master controller 29 for communicating control signals and the like with the operation console 1 and imaging table 10. The rotating section 15 and the body of the scan gantry 20 are electrically connected to each other by a slip ring 30. The X-ray tube 21 and X-ray detector 24 are placed facing each other on either side of an imaging volume in which the subject 40 is placed, i.e., the bore B of the scan gantry 20. A rotation of the rotating section 15 causes the X-ray tube 21 and X-ray detector 24 to rotate around the subject 40 while keeping their positional relationship. The X-rays 81 in the form of a fan or cone beam emitted from the X-ray tube 21 and shaped through the aperture 23 pass through the subject 40 and impinge upon a detecting surface of the X-ray detector 24. As used herein, a body axis direction of the subject 40, i.e., a horizontal direction also defined as a direction of the axis of rotation of the rotating section 15, will be referred to as z-axis direction, a vertical direction as y-axis direction, and a horizontal direction orthogonal to the y- and z-axis directions as x-axis direction. Moreover, a direction of width of an arc of the X-rays 81 emitted in a fan shape from a focal spot f of the X-ray tube 21 will be referred to as fan-angle direction (FAN), a direction of the thickness of the arc of the X-rays 81 as cone-angle direction (CONE), and a direction of a straight line in which the X-rays 81 are emitted from the focal spot f of the X-ray tube 21 as direction of emission (E). The fan-angle direction and/or a tangential direction of the fan angle is also called channel direction (CH), and the z-axis direction and/or cone-angle direction is called slice direction (SL). FIG. 2 is a diagram showing a configuration of the X-ray detector 24 in accordance with the first embodiment. The X-ray detector 24 is mainly comprised of a pair of rails (blocks) consisting of a first rail 51A and a second rail 51B, a pair of spacers consisting of a first spacer 52A and a second spacer 52B, and a plurality of first detector modules 53. The first and second rails 51A, 51B have mutually similar shapes, and generally, are each arcuately curved in the fan-angle direction. The first rail 51A and second rail 51B are positioned in parallel with each other at a specific distance in the z-axis direction. The first and second spacers 52A, 52B have mutually similar shapes, and generally, each have a columnar shape extending in the z-axis direction. The first spacer 52A and second spacer 52B are positioned in parallel with each other at a specific distance in the fan-angle direction (FAN). The first spacer 52A connects respective ends of the pair of rails 51A, 51B on one side in the fan-angle direction (FAN). The second spacer 52B connects respective ends of the pair of rails 51A, 51B on the other side in the fan-angle direction (FAN). The connection is achieved by, for example, screwing (not shown). The plurality of first detector modules 53 each have a generally identical shape having its long-side direction in the z-axis direction. The plurality of first detector modules 53 are tightly arranged in the fan-angle direction (FAN). The plurality of first detector modules 53 each have one of its both ends in the z-axis direction attached to the first rail 51A and the other to the second rail 51B. This attachment is achieved by, for example, screwing (not shown). In practice, each of the plurality of first detector modules 53 is connected with a cable or circuitry for transmitting detected signals to the DAS 25, which is omitted in the drawing here. FIG. 3 is a diagram showing a configuration of a first detector module 53. The first detector module 53 is mainly comprised of a substrate 531, a photodiode array 532, a scintillator array 533, and a collimator module 534. The substrate 531 is a plate-like rectangle having its plate thickness direction in the direction of emission (E) and its long-side direction in the z-axis direction. The substrate 531 is constructed of ceramic, for example. The substrate 531 has the photodiode array 532 formed on its plate surface on a side on which X-rays impinge, and the scintillator array 533 is laid over the photodiode array 532. The photodiode array 532 has a plurality of photodiode elements 532A in the form of a matrix in the channel direction (CH) and slice direction (SL). The scintillator array 533 has a plurality of scintillator elements 533A in the form of a matrix in the channel direction (CH) and slice direction (SL). The scintillator elements 533A and photodiode elements 532A correspond to one another in position in the direction of emission (E). Specifically, a single scintillator element 533A and a single photodiode element 532A corresponding to each other form a single detector element 53A, and the scintillator array 533 and photodiode array 532 form a detector element array 538. The number of detector elements per single detector module is 32 (CH)×64 (SL), for example, and the size of a single detector element is of the order of 1 mm square, for example. In the drawings to be referred to, a number of the detector elements, which is less than the actual number of the detector elements, are drawn for aiding understanding of the structure. The detector element array 538 has the collimator module 534 adhesively secured on its surface on a side on which X-rays impinge, i.e., over the scintillator array 533, by an adhesive (not shown). The collimator module 534 is constructed of heavy metal such as, for example, tungsten or molybdenum. Moreover, the collimator module 534 is fabricated by a technique called DMLM (Direct Material Laser Melting), for example, which involves depositing layers of powder of such heavy metal melted using laser to form a desired shape. The collimator module 534 is formed with grid-like walls that two-dimensionally separate individual detector elements 53A in the channel direction (CH) and slice direction (SL). Surfaces of the grid-like walls are each formed to align with the direction of emission (E). Thus, the collimator module 534 has outer end surfaces on both sides in the fan-angle direction (FAN) and those in the cone-angle direction (CONE) tapered to align with the direction of emission. FIG. 4 is a vertical cross-sectional view representing a cross section perpendicular to the fan-angle direction (FAN) of the X-ray detector 24 in accordance with the first embodiment. The detector modules 53 are each secured to the pair of rails 51A, 51B by screwing both ends of its substrate 531 in the z-axis direction thereto. The pair of rails 51A, 51B are disposed to sandwich the collimator module 534 in each individual detector module 53 in the cone-angle direction (CONE). Inner end surfaces of the pair of rails 51A, 51B on both sides in the z-axis direction are tapered to align with the direction of emission (E). By such a configuration, a what-is-called wedge effect is produced between the collimator module 534 and pair of rails 51A, 51B. Accordingly, even when adhesion between the collimator module 534 and detector element array 538 is broken to cause the collimator module 534 to be delaminated from the detector element array 538, the collimator module 534 is prevented from falling off to the outside of the pair of rails 51A, 51B. The inner end surface in the pair of rails 51A, 51B on either side and the outer end surface in the collimator module 534 on either side lie close to each other separated by a small gap d. The gap d has a size of the order of 10 μm-30 μm, for example. By such a configuration, even when the collimator module 534 and/or pair of rails 51A, 51B thermally expand, the outer end surface in the collimator module 534 on either side is prevented from coming into contact with the inner end surface in the pair of rails 51A, 51B on either side, thus preventing stress in the collimator module 534. FIG. 5 is a partial enlarged view of a vertical cross section of the X-ray detector 24 in accordance with the first embodiment. An elastic material g such as rubber or sponge may be interposed between the inner end surface in the pair of rails 51A, 51B on either side and the outer end surface in the collimator module 534 on either side, as shown in FIG. 5. By such a configuration, even when the collimator module 534 comes off, it is prevented from bumping in the inside of the pair of rails 51A, 51B, which promotes safety. In this embodiment, the component disposed to sandwich the collimator module 534 in the cone-angle direction (CONE) forms part of the pair of rails 51A, 51B to which the detector module 53 is attached. Accordingly, this component does not need to be provided separately, which makes design and assembly easy and allows low-cost implementation. a. FIG. 6 is a diagram showing a configuration of an X-ray detector 24′ in accordance with a second embodiment. The X-ray detector 24′ is mainly comprised of a pair of rails (blocks) consisting of a third rail 61A and a fourth rail 61B, a pair of spacers (blocks) consisting of a third spacer 62A and a fourth spacer 62B, a plurality of detector modules 63, and a base 64. The third and fourth rails 61A, 61B have mutually similar shapes, and generally, are each arcuately curved in the fan-angle direction (FAN). The third rail 61A and forth rail 61B are positioned in parallel with each other at a specific distance in the z-axis direction. The third and fourth spacers 62A, 62B have mutually similar shapes, and generally, each have a columnar shape extending in the z-axis direction. The third spacer 62A and fourth spacer 62B are positioned in parallel with each other at a specific distance in the fan-angle direction (FAN). The third spacer 62A connects respective ends of the pair of rails 61A, 61B on one side in the fan-angle direction (FAN). The forth spacer 62B connects respective ends of the pair of rails 61A, 61B on the other side in the fan-angle direction (FAN). The base 64 is a component having a surface arcuately curved in the fan-angle direction (FAN) and cone-angle direction (CONE), and has a generally rectangular shape having its long-side direction in the fan-angle direction (FAN) as viewed from the focal spot f of the X-ray tube 21. The base 64 is provided with a plurality of second detector modules 63 placed on its curved surface on a side on which X-rays impinge, and the second detector modules 63 are arranged in the fan-angle direction (FAN) and cone-angle direction (CONE). With the plurality of second detector modules 63 placed thereon, the base 64 is connected to the pair of rails 61A, 61B and pair of spacers 62A, 62B from a side on which X-rays exit. The plurality of second detector modules 63 each have a generally identical shape symmetric with respect to the fan-angle direction (FAN) and cone-angle direction (CONE). The plurality of second detector modules 63 are tightly arranged in the fan-angle direction (FAN) and cone-angle direction (CONE) in a region surrounded by the pair of rails 61A, 61B and pair of spacers 62A, 62B. FIG. 7 is a diagram showing a configuration of a second detector module 63. The second detector module 63 is mainly comprised of a substrate 631, a photodiode array 632, a scintillator array 633, and a collimator module 634. The substrate 631 is a plate-like rectangle having its plate thickness direction in the direction of emission (E), and has a square plate surface having its equal sides in the channel direction (CH) and slice direction (SL). The substrate 631 is constructed of ceramic, for example. The substrate 631 has the photodiode array 632 formed on its plate surface on a side on which X-rays impinge, and the scintillator array 633 is laid over the photodiode array 632. The photodiode array 632 has a plurality of photodiode elements 632a in the form of a matrix in the channel direction (CH) and slice direction (SL). The scintillator array 633 has a plurality of scintillator elements 633a in the form of a matrix in the channel direction (CH) and slice direction (SL). The scintillator elements 633a and photodiode elements (632A) correspond to one another in position in the direction of emission (E). Specifically, a single scintillator element 633A and a single photodiode element (632A) corresponding to each other form a single detector element 63A, and the scintillator array 633 and photodiode array 632 form a detector element array 638. The number of detector elements per single detector module is 16 (CH)×16 (SL), for example, and the size of a single detector element is of the order of 1 mm square, for example. In the drawings to be referred to, a number of the detector elements, which is less than the actual number of the detector elements, are drawn for aiding understanding of the structure. The detector element array 638 has the collimator module 634 adhesively secured on its surface on a side on which X-rays impinge, i.e., over the scintillator array 633, by an adhesive (not shown). The collimator module 634 is constructed of heavy metal such as, for example, tungsten or molybdenum. The collimator module 634 is formed with grid-like walls that two-dimensionally separate individual detector elements 63A in the channel direction (CH) and slice direction (SL). Surfaces of the grid-like walls are each formed to align with the direction of emission (E). Thus, the collimator module 634 has outer end surfaces on both sides in the fan-angle direction (FAN) and those in the cone-angle direction (CONE) tapered to align with the direction of emission. FIG. 8 is a vertical cross-sectional view representing a cross section perpendicular to the cone-angle direction (CONE) of the X-ray detector 24′ in accordance with the second embodiment. FIG. 9 is a vertical cross-sectional view representing a cross section perpendicular to the fan-angle direction (FAN) of the X-ray detector 24′ in accordance with the second embodiment. The individual second detector modules 63 have their substrate 631 adhesively secured to a side of the base 64 on which X-rays impinge. The pair of rails 61A, 61B are disposed to sandwich the collimator modules 634 in the cone-angle direction (CONE) in the second detector modules 63 arranged in the cone-angle direction (CONE). Inner end surfaces in the pair of rails 61A, 61B on both sides in the cone-angle direction (CONE) are tapered to align with the direction of emission (E). Moreover, the pair of spacers 62A, 62B are disposed to sandwich the collimator modules 634 in the fan-angle direction (FAN) in the second detector modules 63 arranged in the fan-angle direction (FAN). Inner end surfaces in the pair of spacers 62A, 62B on both sides in the fan-angle direction (FAN) are tapered to align with the direction of emission (E). By such a configuration, a what-is-called wedge effect is produced between the plurality of collimator modules 634 arranged in the cone-angle direction (CONE) and the pair of rails 61A, 61B. The wedge effect is also produced between the plurality of collimator modules 634 arranged in the fan-angle direction (FAN) and the pair of spacers 62A, 62B. Accordingly, even when adhesion between the collimator module 634 and detector element array 638 is broken to cause the collimator module 634 to be delaminated from the detector element array 638, the collimator module 634 is prevented from falling off to the outside of the pair of rails 61A, 61B and pair of spacers 62A, 62B. The inner end surface in the pair of rails 61A, 61B on either side in the cone-angle direction (CONE) and the outer end surface in the whole collimator modules 634 arranged in the cone-angle direction (CONE) on either side in the cone-angle direction (CONE) lie close to each other separated by a small gap d. Moreover, the inner end surface in the pair of spacers 62A, 62B on either side in the fan-angle direction (FAN) and the outer end surface in the whole collimator modules 634 arranged in the fan-angle direction (FAN) on either side in the fan-angle direction (FAN) also lie close to each other separated by a small gap d. These gaps d each have a size of the order of 10 μm-30 μm, for example. By such a configuration, even when the collimator module 634, pair of rails 61A, 61B and/or pair of spacers 62A, 62B thermally expand, the outer end surface in the collimator modules 634 on either side is prevented from coming into contact with the pair of rails 61A, 61B and/or pair of spacers 62A, 62B, thus preventing stress in the collimator modules 634. FIG. 10 is a partial enlarged view of a vertical cross section of the X-ray detector 24′ in accordance with the second embodiment. In the present embodiment, an elastic material g such as rubber or sponge may be interposed between the inner end surface in the pair of spacers 62A, 62B on either side in the fan-angle direction (FAN) and the outer end surface in the plurality of collimator modules 634 arranged in the fan-angle direction (FAN) on either side in the fan-angle direction (FAN), as shown in FIG. 10. Likewise, an elastic material g such as rubber or sponge may be interposed between the inner end surface in the pair of rails 61A, 61B on either side in the cone-angle direction (CONE) and the outer end surface in the plurality of collimator modules 634 arranged in the cone-angle direction (CONE) on either side in the cone-angle direction (CONE). By such a configuration, even when the collimator module 634 comes off, it is prevented from bumping in the inside of pair of rails 61A, 61B and pair of spacers 62A, 62B, which promotes safety. Moreover, the second detector module 63 may have a configuration in which a plurality of collimator modules are combined with a single detector element array 638. By such a configuration, reduction of process steps in fabrication or assembly of the X-ray detector 24′ and enhancement of accuracy may be possible. According to the embodiments described above, the X-ray detector comprises a collimator having outer end surfaces on both sides in a specified direction tapered, the direction being a cone-angle direction (CONE) or a fan-angle direction (FAN), and a pair of blocks disposed to sandwich the aforementioned collimator in the aforementioned specified direction, and having inner end surfaces on both sides in the aforementioned specified direction tapered; thus, even in case that adhesive delamination occurs between the collimator and detector element array, the collimator can be prevented from falling off from the aforementioned X-ray detector by a what-is-called wedge effect. The present invention is not limited to the embodiments described above and several modifications may be made without departing from the spirit and scope of the invention. For example, while the embodiments described above refer to the X-ray CT apparatus, the present invention may be applied to a PET-CT or SPECT-CT apparatus in which an X-ray CT apparatus is combined with PET or SPECT. |
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claims | 1. A system for positioning handling structures with articles for handling, the system comprising:a handling structure moveable over an area bounded by a boundary structure and populated by at least one article, wherein the handling structure is configured to move the article;a first emitter rigidly attached to the handling structure configured to emit visible light forming a first plane; anda second emitter rigidly attached to the handling structure configured to emit visible light forming a second plane, wherein an intersection of the first plane and the second plane forms a line extending directly from the area axially upward toward the handling structure, wherein an intersection of the first plane and the boundary structure creates a first visible intersection point horizontally aligned with the handling structure, and wherein an intersection of the second plane and the boundary structure creates a second visible intersection point vertically aligned with the handling structure. 2. The system of claim 1, further comprising:a sensor configured to detect at least one of, the intersection of the first plane and the second plane, and the first and the second intersection points; anda computer processor configured to determine a position of the handling structure from the at least one of, the intersection of the first plane and the second plane, and the first and the second intersection points. 3. The system of claim 2, further comprising:a controller configured to move the handling structure over the area and raise and lower the handling structure to move the article, wherein the computer processor is further configured to control the controller to move the handling structure based on the determined position. 4. The system of claim 3, wherein the computer processor is further configured to control the controller to move the handling structure based on a list of positions versus articles. 5. The system of claim 4, further comprising:the area, wherein the area is a nuclear reactor core; andthe article, wherein the article is a nuclear fuel assembly, and wherein the handling structure is a refueling bridge including an axially extensible mast that moves the nuclear fuel assembly. 6. A system for determining position of fuel handling structures in a nuclear reactor environment, the system comprising:a fuel handling structure moveable over a volume populated by nuclear fuel;an emitter system rigidly attached to the handling structure, wherein the emitter system emits, a first visible plane of light axially downward and horizontally to visibly intersect a boundary structure of the volume at a first point and a nuclear fuel assembly of the nuclear fuel, and a second visible plane of light axially downward and vertically to visibly intersect the boundary structure at a second point and the nuclear fuel assembly, wherein the first visible plane of light and the second visible plane of light intersect each other only on a line extending axially upward from the nuclear fuel assembly to the fuel handling structure. 7. The system of claim 6, wherein the emitter system is rigidly attached to a refueling bridge, a trolley on the refueling bridge, a mast extending axially from the trolley, or a grapple extending axially from the mast. 8. The system of claim 7, wherein the volume is a nuclear fuel core in a nuclear reactor, and wherein the boundary structure is at an outermost periphery of the core. 9. The system of claim 8, wherein the emitter system configured to operate underwater in reactor coolant water emit light visible after passing through at least twenty-five feet of the coolant water. 10. The system of claim 8, wherein the first and the second planes of light are formed by lasers. 11. The system of claim 6, further comprising:a sensor configured to detect the first point and the second point; anda computer processor configured to determine a position of the fuel handling structure from the first and the second points. 12. The system of claim 11, further comprising:a controller configured to move the fuel handling structure over the volume and raise and lower the fuel handling structure with respect to the volume, wherein the computer processor is further configured to control the controller to move the fuel handling structure based on the determined position. 13. The system of claim 12, wherein the computer processor is further configured to control the controller to move the handling structure based on a list of core positions versus fuel assemblies. 14. The system of claim 6, wherein the emitter system includes an offset emitter, wherein the fuel handling structure includes a mast extending axially from a refueling bridge, and wherein the offset emitter is mounted on the refueling bridge. 15. The system of claim 14wherein the offset emitter is a different color and separately operable from other emitters of the emitter system. 16. The system of claim 14wherein the offset emitter is configured to emit the first plane of light. 17. The system of claim 16, wherein the first plane of light is at an angle to the axial direction, and wherein the second plane of light is only in the axial direction. |
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060289066 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below using FIG. 1 to FIG. 4. FIG. 4 shows the structure of a control rod for an advanced boiling water reactor, having an oval metal hafnium tube, that has been subjected to anodizing film treatment, in the embodiment of the present invention. This control rod comprises an upper handle 2, a tie rod 5, a sheath 3, a lower connector plate 6, and a coupling socket 7, and is structured with oval tubes of metal hafnium 4 contained inside the sheath 3. FIG. 1(a) is a horizontal cross section of a region containing the neutron absorber material of the control rod shown in FIG. 4. Each end of the cruciform tie rod 5 is groove shaped, sheaths 3 formed with a U-shaped cross-section are welded to each end of the tie rod 5, and two oval metal hafnium tubes are contained in each space thus formed. There are cases where the plate thickness of metal hafnium is caused to vary in the direction of the axis of the control rod, and cases where the metal hafnium is further divided into a number of tubes in the axis direction. FIG. 1(b) is an enlarged schematic drawing of the oval tube metal hafnium 4 of the present invention. The oval tubular shape of the metal hafnium is formed by half oval shapes like the members 4-1 and 4-2 shown in FIG. 1 by subjecting metal hafnium plates to bending, then the members 1-4 and 1-2 are joined at the ends and fixed by welding. A surface oxide film 4' is formed on the surface of the oval hafnium tubes by anodizing. FIG. 2 is a flowchart showing the fabrication sequence for metal hafnium, having an oval tube cross section and provided with an anodized film. The raw material is pure metal hafnium having purity of 95% or more, and material certification is carried out at the time of entering the manufacturing process. Next, bending work is carried out using a pressbrake to impart a radius of curvature at both ends of the long plates. Machining of the grooves for welding is then carried out. After that, welding inspection certification, and cleaning treatment is carried out. At this stage, the two oval tube half members 4-1 and 4-2 shown in FIG. 1 have been formed. The two oval halves are joined at the ends, and an oval tube is made by welding them together. Machining is then carried out to form cooling holes and fixing holes, etc. in the oval tube, and finishing processing is carried out. At the stage where these processes have been completed, anodizing treatment is carried out in an electrolyte bath. FIG. 3 is a schematic drawing showing equipment for carrying out the anodizing treatment. Anode material comprising a stainless steel anode 9, for anodizing the outer surface of the metal hafnium, integrally formed with a stainless steel anode 9' for anodizing the inner surface of the metal hafnium tube, is provided in the electrolytic bath 11, and the electrolytic bath 11 is filled with electrolyte 10. Circular holes 4h for fixing to a control rod structural member is formed in the metal hafnium oval tube, at an end in the longitudinal direction, and the metal hafnium is lowered using these circular holes 4h. A metal hafnium rod having a diameter smaller than the internal diameter of the circular hole 4h is passed through the circular holes 4h, and is connected to positive electrodes of a direct current source 12 by conductors through a raising and lowering device 13. On the other hand, a conductor is taken out from the anode in the electrolytic bath, and connected to the negative electrode of the direct current source 12. The metal hafnium pipe suspended from the metal hafnium rod 8 is dipped into the electrolytic bath, by the raising and lowering device 13, so that the stainless steel anode 9' having a smaller diameter that the internal diameter of the tube is inserted into the metal hafnium tube. When anodizing treatment is carried out, there is a current density per unit surface area of a cover oxide member at a level necessary to obtain a uniform oxidation film. As a result, in processing material having a fixed area, like the neutron absorber material used in the control rod in one go, there is a possibility that the necessary current level will become large, exceeding the normal usage range. Using the raising and lowering mechanism 13 as shown in FIG. 3, the processing region of the cover oxide member is divided into a few areas, to provide processing equipment that can carry out the process with a current level within a practical range. With respect to a necessary current density for anodizing metal hafnium at mass production levels, requirements are determined by additional measurements, but with examined effects for zircalloy having the same crystal lattice interstitial as hafnium and for which characteristics such as oxidation etc. are analogous, current density of about 1A/dm.sup.2 is obtained. If calculations are made based on this, then in controlling processing current to be in a normal household level of 10A, in the case of an oval metal hafnium tube having a length of about 1800 mm and a width of about 50 mm, it can be presumed that it would be appropriate to divide the metal hafnium oval tube into four stages. Therefore, at a first stage a quarter of the length of the metal hafnium oval tube is dipped in the electrolytic bath, current flows from the direct current source, and an anodized film is formed. After the anodized film has stabilized, the anodizing treated metal hafnium tube is lowered by the raising and lowering device, and a further quarter of the hafnium tube is dipped in the electrolytic bath, so that half of the tube is now immersed, and anodizing treatment is carried out. Subsequently, a stabilized anodized film is formed in third and fourth stages. Using the above process, the oval metal hafnium tube that has been provided with an anodized film on the surface is then subjected to inspection, is cleaned, and then normally progresses to control rod assembly processing, which completes the control rod containing neutron absorber material that has been subjected to anodizing treatment. A specific method of providing the anodized film on the surface of the metal hafnium will be described below. Short test pieces have been prepared using a hafnium rod having the technical specifications of an actual reactor control rod. Because film certification is carried out at a welded portion, weld material was also prepared as a test piece. Electrolyte used in the test was ammonium borate [1% (NH.sub.4).sub.2 O.5B.sub.2 0.sub.3 ]. As a general electrolyte for use in anodizing treatment, KOH or NaOH can be used, but as boric oxide ions are larger than ions of metal such as K and Na etc., it is considered that they will have difficulty in sticking to the hafnium rod as impurities, which is why the aforementioned electrolyte is used. The electrolytic bath is filled with the electrolyte, and anodizing treatment is carried out using platinum as a cathode and the hafnium rod as an anode. At room temperature, direct current at fixed voltages of 100V, 200V and 300V is respectively made to flow between the two electrodes. The period of time for which current flow is maintained was five minutes, for the anodized film formed on the test piece to stabilize. With the above described method, visual inspection, corrosion resistance test and hardness test are carried out on the test piece which has been subjected to anodizing treatment. Through the visual inspection formation of similar anodized film was observed on test pieces to which direct current having the foregoing values was applied. The surfaces of the welded portion were also no different from the surface of the base material, and it was observed that a favorable anodized film was formed. Because of the influence of voltage, the tone of cover films formed at voltages from 100V to 300V varied from dark blue to dark green. This is a variation in the anodized film formed, and the thickness of a cover film can be judged from the tone. FIG. 5 is a drawing showing oxidation weight after corrosion testing of the test piece that has been subjected to anodizing film treatment, under the conditions of a test temperature of 410.degree. C. for eight hours and 530.degree. C. for 16 hours, pressure of 105 kg/cm.sup.2, dissolved oxygen of 200-400 ppb, and flow rate of 10 liters per hour. The metal hafnium that has been provided with the anodized film was observed to have a tendency toward improved corrosion resistance compared to the base material without the anodized film. FIG. 6 shows the measurement results of a hardness test on the test piece provided with the anodized film, taken using a Micro Vickers hardness meter. The metal hafnium that has been provided with the anodized film was observed to have a tendency towards increased surface hardness compared to the base material without the anodized film. However, if the compression load was increased, the hardness of the test piece provided with the anodized film tended to decrease, but with this increased load a compression head destroyed the cover film, and it can be considered that the cover film was also affected by the hardness of the internal base material. From the above described tests, it will be understood that an anodized film having excellent corrosion resistance and excellent wear resistance can be provided on the surface of metal hafnium that has welded portions, in a comparatively short time. With a control rod that is actually manufactured, in the case of a hafnium control rod used in an advanced boiling water reactor using metal hafnium oval tubes as a neutron absorber material, in the manufacturing process shown in FIG. 2, there are cases where metal hafnium oval tubes are manufactured. In such a case, the previously described anodizing treatment process is added in the final process shown in FIG. 2, by using equipment for electrolytic treatment as shown in FIG. 3, there will be no significant influence on the manufacturing process, and it is possible to provide a neutron absorber material having excellent corrosion resistance and wear resistance. In the test, using voltage from 100V to 300V, favorable results are obtained in that the corrosion resistance and wear resistance do not differ greatly with different voltages, but in the processing for an actual product, a relationship between stable film formation and voltage or current value should be understood using an actual electrolytic bath, so that production will be carried out under ideal conditions to give high production efficiency. |
claims | 1. A method of evaluating pellet-cladding interaction in a core of a nuclear reactor, said nuclear reactor core having a reactor protection system, and including a plurality of elongated fuel rods, said fuel rods each including a cladding tube surrounding a plurality of nuclear fuel pellets with a gap being defined between said nuclear fuel pellets and said cladding tube, said reactor protection system defining a number of operational limits for a plurality of parameters of said core, said operational limits being based, at least in part, upon a predetermined set of technical specifications for said core, said method comprising the steps of:selecting a number of said parameters of said core to be analyzed, including xenon-135 distribution in said core;evaluating the selected parameters at a plurality of statepoints, each of said statepoints corresponding to a predetermined point in time for a predetermined core condition, wherein a set of said statepoints defines a history point, said history point being representative of the operational history of one or more of said fuel rods of said core;generating a model of an operating space of said core based, at least in part, upon said statepoints and plotting said model of said operating space on a display;selecting a loci of statepoints from said statepoints of said model and subjecting said loci of statepoints to a predetermined simulated transient, wherein each of said statepoints of said loci of statepoints falls within the operational limits of said reactor protection system, said loci of statepoints defining a subset of said statepoints within said operating space of said core, the selection of said loci of statepoints being based, at least in part, upon one or more said history point;evaluating said loci of statepoints for pellet-cladding interaction in response to said simulated transient, prior to operation of said nuclear reactor;if pellet-cladding interaction is predicted, then rearranging said fuel rods or adjusting the operational limits of said reactor protection system; andif pellet-cladding interaction is not predicted, then accepting the arrangement of said fuel rods for safe operation in said core. 2. The method of claim 1 further comprising subjecting as said transient, a transient which is representative of a Condition II event. 3. The method of claim 1 further comprising selecting as said parameters, at least one parameter selected from the group consisting of time-in-cycle, xenon distribution, control rod position, and power level. 4. The method of claim 3 further comprising:establishing a set of allowable core operating guidelines in order to provide for the safe operation of said core and to avoid pellet-cladding interaction,selecting a number of fuel rods of said core, the selected fuel rods having a controlling effect on the limits of said operating space, andevaluating the selected fuel rods for compliance with said guidelines. 5. The method of claim 3 further comprising:evaluating the xenon distribution in said core as a function of a delta xenon parameter and a xenon mid parameter,wherein the delta xenon parameter comprises the amount of xenon distributed in the top of said core minus the average amount of xenon in the bottom of said core, andwherein the xenon mid parameter comprises the average distribution of xenon in the middle third of said core over the average xenon distribution of the entire core. 6. The method of claim 1 wherein each said history point comprises at least one history parameter selected from the group consisting of local burnup, local power level, local isotopic concentrations of select nuclei, local effective cold gap, and maximum allowed power; and wherein said at least one history parameter is evaluated for at least one power history for each of said fuel rods, in order to create historical data for each of said fuel rods within said core. 7. The method of claim 6 further comprising:providing a nuclear analysis code,incorporating said historical data into said nuclear analysis code, andemploying said nuclear analysis code to evaluate said core over a fuel cycle under a number of different core operating scenarios, said core operating scenarios being selected from the group consisting of base load operation at 100% power, operation at reduced power, and load follow operation wherein the core power level changes frequently. 8. The method of claim 7 further comprising:comparing the evaluation of said loci of statepoints to said historical data, andaccepting or rejecting said fuel rods for safe operation in said core. 9. The method of claim 1 further comprising employing three-dimensional nuclear core power distribution analysis in order to analyze the potential for pellet-cladding interaction in said fuel rods. 10. The method of claim 1 further comprising:providing as said statepoints, statepoints associated with normal operation of said core, and statepoints associated with said Condition II event, andmodeling and analyzing said fuel rods of said core using a reduced number of said normal operation statepoints and said Condition II statepoints in order to accurately evaluate said fuel rods of said core for pellet-cladding interaction without requiring all of said statepoints for all of said fuel rods of said core to be analyzed individually. |
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043472141 | claims | 1. An apparatus for detecting the location of failed fuel by analyzing tag gas consisting of rare gas released in cover gas from the failed fuel, said rare gas being at least one from the group consisting of Xenon and Krypton, comprising: (a) tag gas collection/enrichment means including at least two activated-charcoal adsorption columns for collecting tag gas from cover gas at an ambient temperature and for enriching said collected tag gas to an analyzable concentration, said columns being connected and being progressively smaller in volume in accordance with the increase in the degree of enrichment of the tag gas to an analyzable concentration; (b) a line for introducing said cover gas containing tag gas into said tag gas collection/enrichment means; (c) tag gas analysis means for analyzing said enriched tag gas to determine the composition thereof; (d) a line for supplying said enriched tag gas to said analysis means; and (e) a line for transmitting residual gas from which said collected gas is separated to a cover gas clean-up system. (a) tag gas collection/enrichment means including a storage tank for collecting the cover gas containing tag gas and a selectively gas-permeable membrane means including a selectively gas permeable membrane formed from one from the group consisting of silicone rubber, porous metal, porous ceramic and tetrafluoroethylene for selectively permeating tag gas at the ambient temperature; (b) a line for introducing said cover gas containing tag gas into said tag gas collection/enrichment means; (c) tag gas analysis means for analyzing said enriched tag gas to determine the composition thereof; (d) a line for supplying said enriched tag gas to said analysis means; and (e) a line for transmitting residual gas from which said collected gas is separated to a cover gas clean-up system. 2. An apparatus according to claim 1, wherein each said ambient-temperature activated-charcoal adsorption column is provided with a heater for desorbing adsorbed tag gas. 3. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are operated within a temperature range of 0.degree. C. to 60.degree. C. to adsorb tag gas. 4. An apparatus according to claim 2, wherein the adsorbed tag gas is removed by heating to at least 300.degree. C. by means of said heater. 5. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are multi-stage arranged in series with one another. 6. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are multi-stage arranged in parallel with one another and are each provided with a storage tank for desorbed gas, said apparatus further comprising a line for transmitting desorbed gas from each said activated-charcoal adsorption column to each corresponding storage tank and a line for refluxing gas from said storage tank to said activated-charcoal adsorption column. 7. An apparatus according to claim 5, wherein said gas separator is operated within a temperature range of 0.degree. C. to 60.degree. C. to permeate the tag gas selectively. 8. An apparatus for detecting the location of failed fuel by analyzing tag gas consisting of rare gas released in cover gas from the failed fuel, comprising: |
claims | 1. A vehicle diagnostic system comprising:a trigger data storage system configured to store:the identity of diagnostic data from a vehicle that is to be monitored for a trigger characteristic;the trigger characteristic; andthe identity of diagnostic data from a vehicle that is to be recorded in response to detection of the trigger characteristic in the diagnostic data that is to be monitored;a diagnostic data storage system configured to store diagnostic data from the vehicle; anda processing system configured to cause the vehicle diagnostic system to:receive from a user of the vehicle diagnostic system:a selection of diagnostic data that is to be monitored for a trigger characteristic from among both digital and analog diagnostic data types;the trigger characteristic; anda selection of diagnostic data that is to be recorded in response to detection of the trigger characteristic from among both the digital and analog diagnostic data types;store the selections and the trigger characteristic in the trigger data storage system;read the selections and the trigger characteristic from the trigger data storage system;receive both analog and digital diagnostic data from the vehicle, including the selection of diagnostic data that is to be monitored and the selection of diagnostic data that is to be recorded;monitor the received diagnostic data that was selected to be monitored to determine whether the received diagnostic data meets the user-specified trigger characteristic; andrecord the received diagnostic data that was selected to be recorded in the diagnostic data storage system in response to a determination that the trigger characteristic has been met. 2. The vehicle diagnostic system of claim 1 wherein the processing system is further configured to cause user-selected digital diagnostic data to be recorded in response to user-selected analog diagnostic data meeting the trigger characteristic. 3. The vehicle diagnostic system of claim 1 wherein the processing system is further configured to cause user-selected analog diagnostic data to be recorded in response to user-selected digital diagnostic data meeting the trigger characteristic. 4. The vehicle diagnostic system of claim 3 wherein the processing system is further configured to cause user-selected digital diagnostic data to be recorded in response to user-selected analog diagnostic data meeting the trigger characteristic. 5. The vehicle diagnostic system of claim 1 wherein:the trigger data storage system is configured to store:an identification of diagnostic data to be monitored of both the digital and analog type;a trigger characteristic of both analog and digital diagnostic data; andan identification of diagnostic data to be recorded of both the digital and analog type; andthe diagnostic data storage system is configured to store diagnostic data of both the analog and digital type. 6. The vehicle diagnostic system of claim 1 wherein:the trigger data storage system is further configured to store a commencement time for recording the diagnostic data that is to be recorded relative to when a determination has been made that the trigger characteristic has been met; andthe processing system is further configured to cause the vehicle diagnostic system to:receive a commencement time from the user for recording of the diagnostic data that is to be recorded relative to when a determination has been made that the trigger characteristic has been met;store the commencement time in the trigger data storage system;read the commencement time from the trigger data storage system; andbegin recording the received diagnostic data that was selected to be recorded at the commencement time. 7. The vehicle diagnostic system of claim 6 wherein the trigger storage system and the processing system are configured to allow the commencement time to be specified to be before or after the trigger characteristic is met. 8. The vehicle diagnostic system of claim 1 wherein:the trigger data storage system is further configured to store a recording length for recording the diagnostic data that is to be recorded;the processing system is further configured to cause the vehicle diagnostic system to:receive a recording length for recording the diagnostic data that is to be recorded from the user;store the recording length in the trigger data storage system;read the recording length from the trigger data storage system; andrecord the received diagnostic data that was selected to be recorded for the recording length in response to a determination that the trigger characteristic has been met. 9. The vehicle diagnostic system of claim 1 wherein the processing system is configured to cause the vehicle diagnostic system to repeatedly request certain types of digital diagnostic information that is selected to be recorded from the vehicle. 10. The vehicle diagnostic system of claim 1 wherein the processing system is configured to cause the vehicle diagnostic system to repeatedly request certain types of digital diagnostic information that is selected to be monitored from the vehicle. 11. The vehicle diagnostic system of claim 1 further including:a digital data connector configured to connect to a data port on the vehicle; andan analog probe configured to extract analog diagnostic information from the vehicle. 12. The vehicle diagnostic system of claim 1:further including a display configured to communicate diagnostic data that is recorded in the diagnostic data storage system to the user; andwherein the processing system is further configured to cause the diagnostic data that is stored in the diagnostic data storage system to be delivered to the display when requested by the user. 13. A vehicle diagnostic method comprising:receiving from a user:a selection of diagnostic data that is to be monitored for a trigger characteristic from among both digital and analog diagnostic data types;the trigger characteristic; anda selection of diagnostic data that is to be recorded in response to detection of the trigger characteristic from among both the digital and analog diagnostic data types;storing the selections and the trigger characteristic;reading the selections and the trigger characteristic;receiving the selections of diagnostic data from the vehicle;monitoring the received diagnostic data that was selected to be monitored to determine whether the received diagnostic data meets the user-specified trigger characteristic; andrecording the received diagnostic data that was selected to be recorded in response to a determination that the trigger characteristic has been met. 14. The vehicle diagnostic method of claim 13 wherein user-selected digital diagnostic data is recorded in response to user-selected analog diagnostic data meeting the trigger characteristic. 15. The vehicle diagnostic method of claim 13 wherein user-selected analog diagnostic data is recorded in response to user-selected digital diagnostic data meeting the trigger characteristic. 16. The vehicle diagnostic method of claim 15 wherein user-selected digital diagnostic data is recorded in response to user-selected analog diagnostic data meeting the trigger characteristic. 17. The vehicle diagnostic method of claim 13 further comprising:receiving a commencement time from the user for recording the diagnostic data that is to be recorded relative to when a determination that the trigger characteristic has been met;storing the commencement time;reading the commencement time; andbeginning to record the received diagnostic data that was selected to be recorded at the commencement time. 18. The vehicle diagnostic method of claim 17 wherein the commencement time is before or after the trigger characteristic is met. 19. The vehicle diagnostic method of claim 13 further comprising:receiving a recording length from the user for recording the diagnostic data that is to be recorded;storing the recording length;reading the recording length; andrecording the received diagnostic data that was selected to be recorded for the recording length in response to a determination that the trigger characteristic has been met. 20. The vehicle diagnostic method of claim 13 further comprising repeatedly requesting the digital diagnostic information that was selected to be recorded from the vehicle. 21. The vehicle diagnostic method of claim 13 further comprising repeatedly requesting the digital diagnostic information that was selected to be monitored from the vehicle. 22. The vehicle diagnostic method of claim 13 further comprising connecting a digital data connector to a data port on the vehicle and attaching an analog probe to the vehicle. 23. The vehicle diagnostic method of claim 13 further comprising delivering the diagnostic data that is stored to a display when requested by the user. 24. A vehicle diagnostic system comprising a processing system configured to cause the vehicle diagnostic system to:monitor analog diagnostic data that is received from a vehicle to determine whether the analog diagnostic data meets a user-specified trigger characteristic; andrecord digital diagnostic data that is received from the vehicle in response to a determination that the trigger characteristic has been met. 25. The vehicle diagnostic system of claim 24 wherein the processing system is also configured to cause the vehicle diagnostic system to receive a selection from a user of the analog diagnostic data that is to be monitored and the digital diagnostic data that is to be recorded, both from among analog and digital diagnostic data types that is received from the vehicle. 26. A vehicle diagnostic method comprising:monitoring analog diagnostic data that is received from a vehicle to determine whether the analog diagnostic data meets a user-specified trigger characteristic; andrecording digital diagnostic data that is received from the vehicle in response to a determination that the trigger characteristic has been met. 27. The vehicle diagnostic method of claim 26 further comprising receiving a selection from a user of the analog diagnostic data that is to be monitored and the digital diagnostic data that is to be recorded, both from among analog and digital data types. 28. A vehicle diagnostic system comprising a processing system configured to cause the vehicle diagnostic system to:monitor digital diagnostic data that is received from a vehicle to determine whether the digital diagnostic data meets a user-specified trigger characteristic; andrecord analog diagnostic data that is received from the vehicle in response to a determination that the trigger characteristic has been met. 29. The vehicle diagnostic system of claim 28 wherein the processing system is also configured to cause the vehicle diagnostic system to receive from a user a selection of the digital diagnostic data that is to be monitored and the analog diagnostic data that is to be recorded, both from among analog and digital data types. 30. A vehicle diagnostic method comprising:monitoring digital diagnostic data that is received from a vehicle to determine whether the digital diagnostic data meets a user-specified trigger characteristic; andrecording analog diagnostic data that is received from the vehicle in response to a determination that the trigger characteristic has been met. 31. The vehicle diagnostic method of claim 30 further comprising receiving a selection from a user of the digital diagnostic data that is to be monitored and the analog diagnostic data that is to be recorded, both from among analog and digital data types. |
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description | This application claims benefit of provisional applications 60/115,133, filed Jan. 7, 1999, 60/157,633, filed Oct. 4, 1999, 60/207,711, filed May 26, 2000, and 60/207,713, filed May 26, 2000, the complete disclosures of which are incorporated herein by reference. This application is also a continuation-in-part of application Ser. No. 09/477,997, filed Jan. 5, 2000, the complete disclosure of which is incorporated herein by reference. This invention was made with government support under grant F49620-98-1-0418 from the Air Force Office Of Science Research. The government has rights in the invention. This invention relates to methods of microfabrication and nanofabrication. The invention also relates to methods of performing atomic force microscope imaging. Lithographic methods are at the heart of modern day microfabrication, nanotechnology and molecular electronics. These methods often rely on patterning a resistive film, followed by a chemical etch of the substrate. Dip pen technology, where ink on a sharp object is transported to a paper substrate by capillary forces, is approximately 4000 years old. Ewing, The Fountain Pen: A Collector's Companion (Running Press Book Publishers, Philadelphia, 1997). It has been used extensively throughout history to transport molecules on macroscale dimensions. By the present invention, these two related but, with regard to scale and transport mechanism, disparate concepts have been merged to create “dip pen” nanolithography (DPN). DPN utilizes a scanning probe microscope (SPM) tip (e.g., an atomic force microscope (AFM) tip) as a “nib” or “pen,” a solid-state substrate (e.g., gold) as “paper,” and molecules with a chemical affinity for the solid-state substrate as “ink.” Capillary transport of molecules from the tip to the solid substrate is used in DPN to directly write patterns consisting of a relatively small collection of molecules in submicrometer dimensions. DPN is not the only lithographic method that allows one to directly transport molecules to substrates of interest in a positive printing mode. For example, microcontact printing, which uses an elastomer stamp, can deposit patterns of thiol-functionalized molecules directly onto gold substrates. Xia et al., Angew. Chem. Int. Ed. Engl., 37:550 (1998); Kim et al., Nature, 376:581 (1995); Xia et al., Science, 273:347 (1996); Yan et al., J. Am. Chem. Soc., 120:6179 (1998); Kumar et al., J. Am. Chem. Soc., 114:9188 (1992). This method is a parallel technique to DPN, allowing one to deposit an entire pattern or series of patterns on a substrate of interest in one step. In contrast, DPN allows one to selectively place different types of molecules at specific sites within a particular type of nanostructure. In this regard, DPN complements microcontact printing and many other existing methods of micro- and nanofabrication. There are also a variety of negative printing techniques that rely on scanning probe instruments, electron beams, or molecular beams to pattern substrates using self-assembling monolayers and other organic materials as resist layers (i.e., to remove material for subsequent processing or adsorption steps). Bottomley, Anal. Chem., 70:425R (1998); Nyffenegger et al., Chem. Rev., 97:1195 (1997); Berggren et al., Science, 269:1255 (1995); Sondag-Huethorstet al., Appl. Phys. Lett., 64:285 (1994); Schoer et al., Langmuir, 13:2323 (1997); Xu et al., Langmuir, 13:127 (1997); Perkins et al., Appl. Phys. Lett., 68:550 (1996); Carr et al., J. Vac. Sci. Technol. A, 15:1446 (1997); Lercel et al., Appl. Phys. Lett., 68:1504 (1996); Sugimura et al., J. Vac. Sci. Technol. A, 14:1223 (1996); Komeda et al., J. Vac. Sci. Technol. A, 16:1680 (1998); Muller et al., J. Vac. Sci. Technol. B, 13:2846 (1995); Kim et al., Science, 257:375 (1992). However, DPN can deliver relatively small amounts of a molecular substance to a substrate in a nanolithographic fashion that does not rely on a resist, a stamp, complicated processing methods, or sophisticated noncommercial instrumentation. A problem that has plagued AFM since its invention is the narrow gap capillary formed between an AFM tip and sample when an experiment is conducted in air which condenses water from the ambient and significantly influences imaging experiments, especially those attempting to achieve nanometer or even angstrom resolution. Xu et al., J. Phys. Chem. B, 102:540 (1998); Binggeli et al., Appl. Phys. Lett, 65:415 (1994); Fujihira et al., Chem. Lett., 499 (1996); Piner et al., Langmuir, 13:6864 (1997). It has been shown that this is a dynamic problem, and water, depending upon relative humidity and substrate wetting properties, will either be transported from the substrate to the tip-or-vice versa. In the latter case, metastable, nanometer-length-scale patterns, could be formed from very thin layers of water deposited from the AFM tip (Piner et al., Langmuir, 13:6864 (1997)). The present invention shows that, when the transported molecules can anchor themselves to the substrate, stable surface structures are formed, resulting in a new type of nanolithography, DPN. The present invention also overcomes the problems caused by the water condensation that occurs when performing AFM. In particular, it has been found that the resolution of AFM is improved considerably when the AFM tip is coated with certain hydrophobic compounds prior to performing AFM. As noted above, the invention provides a method of lithography referred to as “dip pen” nanolithography, or DPN. DPN is a direct-write, nanolithography technique by which molecules are delivered to a substrate of interest in a positive printing mode. DPN utilizes a solid substrate as the “paper” and a scanning probe microscope (SPM) tip (e.g., an atomic force microscope (AFM) tip) as the “pen”. The tip is coated with a patterning compound (the “ink”), and the coated tip is used to apply the patterning compound to the substrate to produce a desired pattern. As presently understood, the molecules of the patterning compound are delivered from the tip to the substrate by capillary transport. DPN is useful in the fabrication of a variety of microscale and nanoscale devices. The invention also provides substrates patterned by DPN, including combinatorial arrays, and kits, devices and software for performing DPN. The invention further provides a method of performing AFM imaging in air. The method comprises coating an AFM tip with a hydrophobic compound. Then, AFM imaging is performed in air using the coated tip. The hydrophobic compound is selected so that AFM imaging performed using the coated AFM tip is improved compared to AFM imaging performed using an uncoated AFM tip. Finally, the invention provides AFM tips coated with the hydrophobic compounds. DPN utilizes a scanning probe microscope (SPM) tip. As used herein, the phrases “scanning probe microscope tip” and “SPM tip” are used to mean tips used in atomic scale imaging, including atomic force microscope (AFM) tips, near field scanning optical microscope (NSOM) tips, scanning tunneling microscope (STM) tips, and devices having similar properties, including devices made especially for DPN using the guidelines provided herein. Many SPM tips are available commercially (e.g., from Park Scientific, Digital Instruments, Molecular Imaging, Nanonics Ltd. and Topometrix). Alternatively, SPM tips can be made by methods well known in the art. For instance, SPM tips can be made by e-beam lithography (e.g., a solid tip with a hole bored in it can be fabricated by e-beam lithography). Most preferably, the SPM tip is an AFM tip. Any AFM tip can be used, and suitable AFM tips include those that are available commercially from, e.g., Park Scientific, Digital Instruments and Molecular Imaging. Also preferred are NSOM tips usable in an AFM. These tips are hollow, and the patterning compounds accumulate in the hollows of the NSOM tips which serve as reservoirs of the patterning compound to produce a type of “fountain pen” for use in DPN. Suitable NSOM tips are available from Nanonics Ltd. and Topometrix. STM tips usable in an AFM are also suitable for DPN, and such tips can be fabricated (see, e.g, Giessibl et al., Science, 289, 422 (2000)) or can be obtained commercially (e.g., from Thermomicroscopes, Digital Instruments, or Molecular Imaging). The tip is also preferably one to which the patterning compound physisorbs only. As used herein “physisorb” means that the patterning compound adheres to the tip surface by a means other than as a result of a chemical reaction (i.e., no chemisorption or covalent linkage) and can be removed from the tip surface with a suitable solvent. Physisorption of the patterning compounds to the tip can be enhanced by coating the tip with an adhesion layer and by proper choice of solvent (when one is used) for the patterning compound. The adhesion layer is a uniform, thin (<10 nm) layer of material deposited on the tip surface which does not significantly change the tip's shape. It should also be strong enough to tolerate AFM operation (force of about 10 nN). Titanium and chromium form very thin uniform layers on tips without changing tip shape significantly, and are well-suited to be used to form the adhesion layer. The tips can be coated with an adhesion layer by vacuum deposition (see Holland, Vacuum Deposition Of Thin Films (Wiley, New York, N.Y., 1956)), or any other method of forming thin metal films. By “proper solvent” is meant a solvent that adheres to (wets) the tip well. The proper solvent will vary depending on the patterning compound used, the type of tip used, whether or not the tip is coated with an adhesion layer, and the material used to form the adhesion layer. For example, acetonitrile adheres well to uncoated silicon nitride tips, making the use of an adhesion layer unnecessary when acetonitrile is used as the solvent for a patterning compound. In contrast, water does not adhere to uncoated silicon nitride tips. Water does adhere well to titanium-coated silicon nitride tips, and such coated tips can be used when water is used as the solvent. Physisorption of aqueous solutions of patterning compounds can also be enhanced by increasing the hydrophilicity of the tips (whether coated or uncoated with an adhesion layer). For instance, hydrophilicity can be increased by cleaning the tips (e.g., with a piranha solution, by plasma cleaning, or with UV ozone cleaning) or by oxygen plasma etching. See Lo et al., Langmuir, 15, 6522-6526 (1999); James et al., Langmuir, 14, 741-744 (1998). Alternatively, a mixture of water and another solvent (e.g., 1:3 ratio of water:acetonitrile) may adhere to uncoated silicon nitride tips, making the use of an adhesion layer or treatment to increase hydrophilicity unnecessary. The proper, solvent for a particular set of circumstances can be determined empirically using the guidance provided herein. The substrate may be of any shape and size. In particular, the substrate may be flat or curved. Substrates may be made of any material which can be modified by a patterning compound to form stable surface structures (see below). Substrates useful in the practice of the invention include metals (e.g., gold, silver, aluminum, copper, platinum, and paladium), metal oxides (e.g., oxides of Al, Ti, Fe, Ag, Zn, Zr, In, Sn and Cu), semiconductor materials (e.g., Si, CdSe, CdS and CdS coated with ZnS), magnetic materials (e.g., ferromagnetite), polymers or polymer-coated substrates, superconductor materials (YBa2Cu3O7-δ), Si, SiO2, glass, AgI, AgBr, HgI2, PbS, PbSe, ZnSe, ZnS, ZnTe, CdTe, InP, In2O3/SnO2, In2S3, In2Se3, In2Te3, Cd3P2, Cd3As2, InAs, AlAs, GaP, and GaAs. Methods of making such substrates are well-known in the art and include evaporation and sputtering (metal films), crystal semiconductor growth (e.g., Si, Ge, GaAs), chemical vapor deposition (semiconductor thin films), epitaxial growth (crystalline semiconductor thim films), and thermal shrinkage (oriented polymers). See, e.g., Alcock et al., Canadian Metallurgical Quarterly, 23, 309 (1984); Holland, Vacuum Deposition of Thin Films (Wiley, New York 1956); Grove, Philos. Trans. Faraday Soc., 87 (1852); Teal, IEEE Trans. Electron Dev. ED-23, 621 (1976); Sell, Key Eng. Materials, 58, 169 (1991); Keller et al., Float-Zone Silicon (Marcel Dekker, New York, 1981); Sherman, Chemical Vapor Deposition For Microelectronics: Principles, Technology And Applications (Noyes, Park Ridges, N.J.,1987); Epitaxial Silicon Technology (Baliga, ed., Academic Press, Orlando, Fla., 1986); U.S. Pat. No. 5,138,174; Hidber et al., Langmuir, 12, 5209-5215 (1996). Suitable substrates can also be obtained commercially from, e.g., Digital Instruments (gold), Molecular Imaging (gold), Park Scientific (gold), Electronic Materials, Inc. (semiconductor wafers), Silicon Quest, Inc. (semiconductor wafers), MEMS Technology Applications Center, Inc. (semiconductor wafers), Crystal Specialties, Inc. (semiconductor wafers), Siltronix, Switzerland (silicon wafers), Aleene's, Buellton, Calif. (biaxially-oriented polystyrene sheets), and Kama Corp., Hazelton, Pa. (oriented thin films of polystyrene). The SPM tip is used to deliver a patterning compound to a substrate of interest. Any patterning compound can be used, provided it is capable of modifying the substrate to form stable surface structures. Stable surface structures are formed by chemisorption of the molecules of the patterning compound onto the substrate or by covalent linkage of the molecules of the patterning compound to the substrate. Many suitable compounds which can be used as the patterning compound, and the corresponding substrate(s) for the compounds, are known in the art. For example: a. Compounds of the formula R1SH, R1SSR2, R1SR2, R1SO2H, (R1)3P, R1NC, R1CN, (R1)3N, R1COOH, or ArSH can be used to pattern gold substrates; b. Compounds of formula R1SH, (R1)3N, or ArSH can be used to pattern silver, copper, palladium and semiconductor substrates; c. Compounds of the formula R1NC, R1SH, R1SSR2, or R1SR2 can be used to pattern platinum substrates; d. Compounds of the formula R1SH can be used to pattern aluminum, TiO2, SiO2, GaAs and InP substrates; e. Organosilanes, including compounds of the formula R1SiCl3, R1Si(OR2)3, (R1COO)2, R1CH═CH2, R1Li or R1MgX, can be used to pattern Si, SiO2 and glass substrates; f. Compounds of the formula R1COOH or R1CONHR2 can be used to pattern metal oxide substrates; g. Compounds of the formula R1SH, R1NH2, ArNH2, pyrrole, or pyrrole derivatives wherein R1 is attached to one of the carbons of the pyrrole ring, can be used to pattern cuprate high temperature superconductors; h. Compounds of the formula R1PO3H2 can be used to pattern ZrO2 and In2O3/SnO2 substrates; i. Compounds of the formula R1COOH can be used to pattern aluminum, copper, silicon and platinum substrates; j. Compounds that are unsaturated, such as azoalkanes (R3NNR3) and isothiocyanates (R3NCS), can be used to pattern silicon substrates; k. Proteins and peptides can be used to pattern, gold, silver, glass, silicon, and polystyrene; and l. Silazanes can be used to pattern SiO2 and oxidized GaAs.In the above formulas: R1 and R2 each has the formula X(CH2)n and, if a compound is substituted with both R1 and R2, then R1 and R2 can be the same or different; R3 has the formula CH3(CH2)n; n is 0-30; Ar is an aryl; X is —CH3, —CHCH3, —COOH, —CO2(CH2)mCH3, —OH, —CH2OH, ethylene glycol, hexa(ethylene glycol), —O(CH2)mCH3, —NH2, —NH(CH2)mNH2, halogen, glucose, maltose, fullerene C60, a nucleic acid (oligonucleotide, DNA, RNA, etc.), a protein (e.g., an antibody or enzyme) or a ligand (e.g., an antigen, enzyme substrate or receptor); and m is 0-30. For a description of patterning compounds and their preparation and use, see Xia and Whitesides, Angew. Chem. Int. Ed., 37, 550-575 (1998) and references cited therein; Bishop et al., Curr. Opinion Colloid & Interface Sci., 1, 127-136 (1996); Calvert, J. Vac. Sci. Technol. B, 11, 2155-2163 (1993); Ulman, Chem. Rev., 96:1533 (1996) (alkanethiols on gold); Dubois et al., Annu. Rev. Phys. Chem., 43:437 (1992) (alkanethiols on gold); Ulman, An Introduction to Ultrathin Organic Films: From Langmuir-Blodgett to Self-Assembly (Academic, Boston, 1991) (alkanethiols on gold); Whitesides, Proceedings of the Robert A. Welch Foundation 39th Conference On Chemical Research Nanophase Chemistry, Houston, Tex., pages 109-121 (1995) (alkanethiols attached to gold); Mucic et al. Chem. Commun. 555-557 (1996) (describes a method of attaching 3′ thiol DNA to gold surfaces); U.S. Pat. No. 5,472,881 (binding of oligonucleotide-phosphorothiolates to gold surfaces); Burwell, Chemical Technology, 4, 370-377 (1974) and Matteucci and Caruthers, J. Am. Chem. Soc., 103, 3185-3191 (1981) (binding of oligonucleotides-alkylsiloxanes to silica and glass surfaces); Grabar et al., Anal. Chem., 67, 735-743 (binding of aminoalkylsiloxanes and for similar binding of mercaptoalkylsiloxanes); Nuzzo et al., J. Am. Chem. Soc., 109, 2358 (1987) (disulfides on gold); Allara and Nuzzo, Langmuir, 1, 45 (1985) (carboxylic acids on aluminum); Allara and Tompkins, J. Colloid Interfate Sci., 49, 410-421 (1974) (carboxylic acids on copper); Iler, The Chemistry Of Silica, Chapter 6, (Wiley 1979) (carboxylic acids on silica); Timmons and Zisman, J. Phys. Chem., 69, 984-990 (1965) (carboxylic acids on platinum); Soriaga and Hubbard, J. Am. Chem. Soc., 104, 3937 (1982) (aromatic ring compounds on platinum); Hubbard, Acc. Chem. Res., 13, 177 (1980) (sulfolanes, sulfoxides and other functionalized solvents on platinum); Hickman et al., J. Am. Chem. Soc., 111, 7271 (1989) (isonitriles on platinum); Maoz and Sagiv, Langmuir, 3, 1045 (1987) (silanes on silica); Maoz and Sagiv, Langmuir, 3, 1034 (1987) (silanes on silica); Wasserman et al., Langmuir, 5, 1074 (1989) (silanes on silica); Eltekova and Eltekov, Langmuir, 3,951 (1987) (aromatic carboxylic acids, aldehydes, alcohols and methoxy groups on titanium dioxide and silica); and Lec et al., J. Phys. Chem., 92, 2597 (1988) (rigid phosphates on metals); Lo et al., J. Am. Chem. Soc., 118, 11295-11296 (1996) (attachment of pyrroles to superconductors); Chen et al., J. Am. Chem. Soc., 117, 6374-5 (1995) (attachment of amines and thiols to superconductors); Chen et al., Langmuir, 12, 2622-2624 (1996) (attachment of thiols to superconductors); McDevitt et al., U.S. Pat. No. 5,846,909 (attachment of amines and thiols to superconductors); Xu et al., Langmuir, 14, 6505-6511 (1998) (attachment of amines to superconductors); Mirkin et al., Adv. Mater. (Weinheim, Ger.), 9, 167-173 (1997) (attachment of amines to superconductors); Hovis et al., J. Phys. Chem. B, 102, 6873-6879 (1998) (attachment of olefins and dienes to silicon); Hovis et al., Surf. Sci., 402-404, 1-7 (1998) (attachment of olefins and dienes to silicon); Hovis et al., J. Phys. Chem. B, 101, 9581-9585 (1997) (attachment of olefins and dienes to silicon); Hamers et al., J. Phys. Chem. B, 101, 1489-1492 (1997) (attachment of olefins and dienes to silicon); Hamers et al., U.S. Pat. No. 5,908,692 (attachment of olefins and dienes to silicon); Ellison et al., J. Phys. Chem. B, 103, 6243-6251 (1999) (attachment of isothiocyanates to silicon); Ellison et al., J. Phys. Chem. B, 102, 8510-8518 (1998) (attachment of azoalkanes to silicon); Ohno et al., Mol. Cryst. Liq. Cryst. Sci. Technol., Sect. A, 295, 487-490 (1997) (attachment of thiols to GaAs); Reuter et al., Mater. Res. Soc. Symp. Proc., 380, 119-24 (1995) (attachment of thiols to GaAs); Bain, Adv. Mater. (Weinheim, Fed. Repub. Ger.), 4, 591-4 (1992) (attachment of thiols to GaAs); Sheen et al., J. Am. Chem. Soc., 114, 1514-15 (1992) (attachment of thiols to GaAs); Nakagawa et al., Jpn. J. Appl. Phys., Part 1, 30, 3759-62 (1991) (attachment of thiols to GaAs); Lunt et al., J. Appl. Phys., 70, 7449-67 (1991) (attachment of thiols to GaAs); Lunt et al., J. Vac. Sci. Technol., B, 9, 2333-6 (1991) (attachment ofthiols to GaAs); Yamamoto et al., Langmuir ACS ASAP, web release number Ia990467r (attachment of thiols to InP); Gu et al., J. Phys. Chem. B, 102, 9015-9028 (1998) (attachment of thiols to InP); Menzel et al., Adv. Mater. (Weinheim, Ger.), 11, 131-134 (1999) (attachment of disulfides to gold); Yonezawa et al., Chem. Mater., 11, 33-35 (1999) (attachment of disulfides to gold); Porter et al., Langmuir, 14, 7378-7386 (1998) (attachment of disulfides to gold); Son et al., J. Phys. Chem., 98, 8488-93 (1994) (attachment of nitriles to gold and silver); Steiner et al., Langmuir, 8, 2771-7 (1992) (attachment of nitriles to gold and copper); Solomun et al., J. Phys. Chem., 95, 10041-9 (1991) (attachment of nitriles to gold); Solomun et al., Ber. Bunsen-Ges. Phys. Chem., 95, 95-8 (1991) (attachment of nitriles to gold); Henderson et al., Inorg. Chim. Acta, 242, 115-24 (1996) (attachment of isonitriles to gold); Huc et al., J. Phys. Chem. B, 103, 10489-10495 (1999) (attachment of isonitriles to gold); Hickman et al., Langmuir, 8, 357-9 (1992) (attachment of isonitriles to platinum); Steiner et al., Langmuir, 8, 90-4 (1992) (attachment of amines and phospines to gold and attachment of amines to copper); Mayya et al., J. Phys. Chem. B, 101, 9790-9793 (1997) (attachment of amines to gold and silver); Chen et al., Langmuir, 15, 1075-1082 (1999) (attachment of carboxylates to gold); Tao, J. Am. Chem. Soc., 115, 4350-4358 (1993) (attachment of carboxylates to copper and silver); Laibinis et al., J. Am. Chem. Soc., 114, 1990-5 (1992) (attachment of thiols to silver and copper); Laibinis et al., Langmuir, 7, 3167-73 (1991) (attachment of thiols to silver); Fenter et al., Langmuir, 7, 2013-16 (1991) (attachment of thiols to silver); Chang et al., Am. Chem. Soc., 116, 6792-805 (1994) (attachment of thiols to silver); Li et al., J. Phys. Chem., 98, 11751-5 (1994) (attachment of thiols to silver); Li et al., Report, 24 pp (1994) (attachment of thiols to silver); Tarlov et al., U.S. Pat. No. 5,942,397 (attachment of thiols to silver and copper); Waldeck, et al., PCT application WO/99/48682 (attachment of thiols to silver and copper); Gui et al., Langmuir, 7, 955-63 (1991) (attachment of thiols to silver); Walczak et al., J. Am. Chem. Soc., 113, 2370-8 (1991) (attachment of thiols to silver); Sangiorgi et al., Gazz. Chim. Ital., 111, 99-102 (1981) (attachment of amines to copper); Magallon et al., Book of Abstracts, 215th ACS National Meeting, Dallas, Mar. 29-Apr. 2, 1998, COLL-048 (attachment of amines to copper); Patil et al., Langmuir, 14, 2707-2711 (1998) (attachment of amines to silver); Sastry et al., J. Phys. Chem. B, 101, 4954-4958 (1997) (attachment of amines to silver); Bansal et al., J. Phys. Chem. B. 102, 4058-4060 (1998) (attachment of alkyl lithium to silicon); Bansal et al., J. Phys. Chem. B, 102, 1067-1070 (1998) (attachment of alkyl lithium to silicon); Chidsey, Book of Abstracts, 214th ACS National Meeting, Las Vegas, Nev., Sep. 7-11, 1997, I&EC-027 (attachment of alkyl lithium to silicon); Song, J. H., Thesis, University of California at San Diego (1998) (attachment of alkyl lithium to silicon dioxide); Meyer et al., J. Am. Chem. Soc., 110, 4914-18 (1988) (attachment of amines to semiconductors); Brazdil et al. J. Phys. Chem., 85, 1005-14 (1981) (attachment of amines to semiconductors); James et al., Langmuir, 14, 741-744 (1998) (attachment of proteins and peptides to glass); Bernard et al., Langmuir, 14, 2225-2229 (1998) (attachment of proteins to glass, polystyrene, gold, silver and silicon wafers); Pereira et al., J. Mater. Chem., 10, 259 (2000) (attachment of silazanes to SiO2); Pereira et al., J. Mater. Chem., 10, 259 (2000) (attachment of silazanes to SiO2); Dammel, Diazonaphthoquinone Based Resists (1st ed., SPIE Optical Engineering Press, Bellingham, Wash., 1993) (attachment of silazanes to SiO2); Anwander et al., J. Phys. Chem. B, 104, 3532 (2000) (attachment of silazanes to SiO2); Slavov et al., J. Phys. Chem., 104, 983 (2000) (attachment of silazanes to SiO2). Other compounds known in the art besides those listed above, or which are developed or discovered using the guidelines provided herein or otherwise, can also be used as the patterning compound. Presently preferred are alkanethiols and arylthiols on a variety of substrates and trichlorosilanes on SiO2 substrates (see Examples 1 and 2). To practice DPN, the SPM tip is coated with a patterning compound. This can be accomplished in a number of ways. For instance, the tip can be coated by vapor deposition, by direct contact scanning, or by bringing the tip into contact with a solution of the patterning compound. The simplest method of coating the tips is by direct contact scanning. Coating by direct contact scanning is accomplished by depositing a drop of a saturated solution of the patterning compound on a solid substrate (e.g., glass or silicon nitride; available from Fisher Scientific or MEMS Technology Application Center). Upon drying, the patterning compound forms a microcrystalline phase on the substrate. To coat the patterning compound on the SPM tip, the tip is scanned repeatedly across this microcrystalline phase. While this method is simple, it does not lead to the best loading of the tip, since it is difficult to control the amount of patterning compound transferred from the substrate to the tip. The tips can also be coated by vapor deposition. See Sherman, Chemical Vapor Deposition For Microelectronics: Principles, Technology And Applications (Noyes, Park Ridges, N.J., 1987. Briefly, a patterning compound in pure form, solid or liquid, no solvent) is placed on a solid substrate (e.g., glass or silicon nitride; obtained from Fisher Scientific or MEMS Technology Application Center), and the tip is positioned near (within about 1-20 cm, depending on chamber design) the patterning compound. The compound is then heated to a temperature at which it vaporizes, thereby coating the tip with the compound. For instance, 1-octadecanethiol can be vapor deposited at 60° C. Coating by vapor deposition should be performed in a closed chamber to prevent contamination of other areas. If the patterning compound is one which is oxidized by air, the chamber should be a vacuum chamber or a nitrogen-filled chamber. Coating the tips by vapor deposition produces thin, uniform layers of patterning compounds on the tips and gives very reliable results in DPN. Preferably, however, the SPM tip is coated by dipping the tip into a solution of the patterning compound. The solvent is not critical; all that is required is that the compound be in solution. However, the solvent is preferably the one in which the patterning compound is most soluble. Also, the solution is preferably a saturated solution. In addition, the solvent is preferably one that adheres to (wets) the tip (uncoated or coated with an adhesion layer) very well (see above). The tip is maintained in contact with the solution of the patterning compound for a time sufficient for the compound to coat the tip. Such times can be determined empirically. Generally, from about 30 seconds to about 3 minutes is sufficient. Preferably, the tip is dipped in the solution multiple times, with the tip being dried between each dipping. The number of times a tip needs to be dipped in a chosen solution can be determined empirically. Preferably, the tip is dried by blowing an inert gas (such as carbon tetrafluoride, 1,2-dichloro-1,1,2,2,-tetrafluoroethane, dichlorodifluoromethane, octafluorocyclobutane, trichlorofluoromethane, difluoroethane,nitrogen, nitrogen, argon or dehumidified air) not containing any particles (i.e., purified) over the tip. Generally, about 10 seconds of blowing with the gas at room temperature is sufficient to dry the tip. After dipping (the single dipping or the last of multiple dippings), the tip may be used wet to pattern the substrate, or it may be dried (preferably as described above) before use. A dry tip gives a low, but stable, rate of transport of the patterning compound for a long time (on the order of weeks), whereas a wet tip gives a high rate of transport of the patterning compound for a short time (about 2-3 hours). A dry tip is preferred for compounds having a good rate of transport under dry conditions (such as the compounds listed above wherein X=—CH3), whereas a wet tip is preferred for compounds having a low rate of transport under dry conditions (such as the compounds listed above wherein X=—COOH). To perform DPN, the coated tip is used to apply a patterning compound to a substrate so as to form a desired pattern. The pattern may be any pattern and may be simple or complex. For instance, the pattern may be a dot, a line, a cross, a geometric shape (e.g, a triangle, square or circle), combinations of two or more of the foregoing, combinatorial arrays (e.g., a square array of rows and columns of dots), electronic circuits, or part of, or a step in, the formation of a three-dimensional structure. A transport medium is preferably used in DPN since, as presently understood, the patterning compound is transported to the substrate by capillary transport. The transport medium forms a meniscus which bridges the gap between the tip and the substrate (see FIG. 1). Thus, the tip is “in contact” with the substrate when it is close enough so that this meniscus forms. The tip may be actually touching the substrate, but it need not be. The tip only needs to be close enough to the substrate so that a meniscus forms. Suitable transport media include water, hydrocarbons (e.g., hexane), and solvents in which the patterning compounds are soluble (e.g., the solvent used for coating the tip—see above). Faster writing with the tip can be accomplished by using the transport medium in which the patterning compound is most soluble. The possibility that the patterning compound can be deposited on the substrate without the use of a transport medium has not been completely ruled out, although it seems highly unlikely. Even under conditions of low, or even no humidity, there is likely some water on the substrate which could function as the transport medium DPN is performed using an AFM or a device performing similar functions and having similar properties, including devices developed especially for performing DPN using the guidelines provided herein, using techniques that are conventional and well known in AFM microscopy. Briefly, the substrate is placed in the sample holder of the device, the substrate is contacted with the SPM tip(s) coated with the patterning compound(s), and the substrate is scanned to pattern it with the patterning compound(s). An AFM can be operated in several modes, and DPN can be performed when the AFM or similar device is operated in any of these modes. For instance, DPN can be performed in (1) contact (constant force) mode wherein the tip is maintained in contact with (touching) the substrate surface, (2) non-contact (dynamic) mode wherein the tip is vibrated very close to the substrate surface, and/or (3) intermittent contact (tapping) mode which is very similar to the non-contact mode, except that the tip is allowed to strike (touch) the surface of the substrate. Single tips can be used to write a pattern utilizing an AFM or similar device. Two or more different patterning compounds can be applied to the same substrate to form patterns (the same or different) of the different compounds by: (1) removing a first tip coated with a first patterning compound and replacing it with another tip coated with a different patterning compound; or (2) rinsing the first tip coated with the first patterning compound so as to remove the patterning compound from the tip and then coating the tip with a different patterning compound. Suitable solvents for rinsing tips to remove patterning compounds are those solvents in which the patterning compound is soluble. Preferably, the rinsing solvent is the solvent in which the patterning compound is most soluble. Rinsing of tips can be accomplished by simply dipping the tip in the rinsing solvent. Alternatively, a plurality of tips can be used in a single AFM or similar device to write a plurality of patterns (the same pattern or different patterns) on a substrate using the same or different patterning compounds (see, e.g., Example 6 below, U.S. Pat. Nos. 5,630,92, and 5,666,190, Lutwyche et al., Sens. Actuators A, 73:89 (1999), Vettiger et al., Microelectron Eng., 46:11 (1999), Minne et al., Appl. Phys. Lett., 73:1742 (1998), and Tsukamoto et al., Rev. Sci. Instrum., 62:1767 (1991) which describe devices comprising multiple cantilevers and tips for patterning a substrate). One or more of the plurality of tips can be rinsed as described above for single tips, if desired, to change the patterning compound coated on the tip(s). The AFM or similar device used for DPN preferably comprises at least one micron-scale well positioned so that the well(s) will be adjacent the substrate when the substrate is placed in the sample holder. Preferably the AFM or similar device comprises a plurality of wells holding a plurality of patterning compounds or holding at least one patterning compound and at least one rinsing solvent. “Well” is used herein to mean any container, device, or material that can hold a patterning compound or rinsing solvent and includes depressions, channels and other wells which can be prepared by microfabrication (e.g, the same processes used to fabricate microelectronic devices, such as photolithograpy; see, e.g., PCT application WO 00/04390). The wells may also simply be pieces of filter paper soaked in a patterning compound or rinsing solvent. The wells can be mounted anywhere on the AFM or similar device which is adjacent the substrate and wherey they can be addressed by the SPM tip(s), such as on the sample holder or translation stage. When two or more patterns and/or two or more patterning compounds (in the same or different patterns) are applied to a single substrate, a positioning (registration) system is used to align the patterns and/or patterning compounds relative to each other and/or relative to selected alignment marks. For instance, two or more alignment marks, which can be imaged by normal AFM imaging methods, are applied to the substrate by DPN or another lithographic technique (such as photolithography or e-beam lithography). The alignment marks may be simple shapes, such as a cross or rectangle. Better resolution is obtained by making the alignment marks using DPN. If DPN is used, the alignment marks are preferably made with patterning compounds which form strong covalent bonds with the substrate. The best compound for forming the alignmeni marks on gold substrates is 16-mercaptohexadecanoic acid. The alignment marks are imaged by normal AFM methods (such as lateral force AFM imaging, AFM topography imaging and non-contact mode AFM imaging), preferably using an SPM tip coated with a patterning compound for making a desired pattern. For this reason, the patterning compounds used to make the alignment marks should not react with the other patterning compounds which are to be used to make the desired patterns and should not be destroyed by subsequent DPN patterning. Using the imaging data, the proper parameters (position and orientation) can be calculated using simple computer programs (e.g., Microsoft Excel spreadsheet), and the desired pattern(s) deposited on the substrate using the calculated parameters. Virtually an infinite number of patterns and/or patterning compounds can be positioned using the alignment marks since the system is based on calculating positions and orientations relative to the alignment marks. To get the best results, the SPM tip positioning system which is used should be stable and not have drift problems. One AFM positioning system which meets these standards is the 100 micrometer pizoelectric tube scanner available from Park Scientific. It provides stable positioning with nanometer scale resolution. DPN can also be used in a nanoplotter format by having a series of wells containing a plurality of different patterning compounds and rinsing solvents adjacent the substrate. One or more tips can be used. When a plurality of tips is used, the tips can be used serially or in parallel to produce patterns on the substrate. In a nanoplotter format using a single tip, the tip is dipped into a well containing a patterning compound to coat the tip, and the coated tip is used to apply a pattern to the substrate. The tip is then rinsed by dipping it in a well containing a rinsing solvent or a series of such wells. The rinsed tip is then dipped into another well to be coated with a second patterning compound and is used to apply a pattern to the substrate with the second patterning compound. The patterns are aligned as described in the previous paragraph. The process of coating the tip with patterning compounds, applying a pattern to the substrate, and rinsing the tip, can be repeated as many times as desired, and the entire process can be automated using appropriate software. A particularly preferred nanoplotter format is described in Example 6 and illustrated in FIGS. 17 and 18. In this preferred format, a plurality of AFM tips are attached to an AFM. A multiple-tip array can be fabricated by simply physically separating an array of the desired number of cantilevers from a commercially-available wafer block containing a large number of individual cantilevers, and this array can be used as a single cantilever on the AFM. The array can be attached to the AFM tip holder in a variety of ways, e.g, with epoxy glue. Of course, arrays of tips of any spacing or configuration and adapted for attachment to an AFM tip holder can be microfabricated by methods known in the art. See, e.g., Minne et al., Applied Physics Letters, 72:2340 (1998). The plurality of tips in the array can be employed for serial or parallel DPN. When the plurality of tips is used for parallel DPN, only one of the tips needs to be connected to a feedback system (this tip is referred to as the “imaging tip”). The feedback system is a standard feedback system for an AFM and comprises a laser, photodiode and feedback electronics. The remaining tips (referred to as “writing tips”) are guided by the imaging tip (i.e., all of the writing tips reproduce what occurs at the imaging tip in passive fashion). As a consequence, all of the writing tips will produce the same pattern on the substrate as produced by the imaging tip. Of course, each writing tip may be coated with a patterning compound which is the same or different than that coated on the imaging tip or on the other writing tips, so that the same pattern is produced using the same patterning compound or using different patterning compounds. When serial DPN is employed, each of the tips used in sequence must be connected to a feedback system (simultaneously or sequentially). The only adaptation of the AFM necessary to provide for a choice of serial or parallel DPN is to add a tilt stage to the AFM. The tilt stage is adapted for receiving and holding the sample holder, which in turn is adapted for receiving and holding the substrate. Tilt stages are included with many AFM's or can be obtained commercially (e.g., from Newport Corp.) and attached to the AFM according to the manufacturer's instructions. The AFM preferably also comprises aplurality ofwells located adjacent the substrate and so that the AFM operator can individually address and coat the tips with patterning compounds or rinse the tips with rinsing solvents. Some AFM's are equipped with a translation stage which can move very large distances (e.g., the M5 AFM from Thermomicroscopes), and the wells can be mounted on this type of translation stage. For inking or rinsing, a well is moved below an AFM tip by the translation stage and, then, the tip is lowered by a standard coarse approach motor until it touches the ink or solvent in the well. The tip is held in contact with the ink or solvent in order to coat or rinse the tip. The wells could also be mounted on the sample holder or tilt stage. DPN can also be used to apply a second patterning compound to a first patterning compound which has already been applied to a substrate. The first patterning compound can be applied to the substrate by DPN, microcontact printing (see, e.g, Xia and Whitesides, Angew. Chem. Ind. Ed., 37, 550-575 (1998); James et al., Langmuir, 14, 741-744 (1998); Bernard et al., Langmuir, 14, 2225-2229 (1998); Huck et al., Langmuir, 15, 6862-6867 (1999)), by self-assembly of a monolayer on a substrate immersed in the compound (see, e.g, Ross et al., Langmuir, 9, 632-636 (1993); Bishop and Nuzzo, Curr. Opinion in Colloid & Interface Science, 1, 127-136 (1996); Xia and Whitesides, Angew. Chem. Ind Ed., 37, 550-575 (1998);Yan et al., Langmuir, 15, 1208-1214 (1999); Lahiri et al., Langmuir, 15, 2055-2060 (1999); Huck et al., Langmuir, 15, 6862-6867 (1999)), or any other method. The second patterning compound is chosen so that it reacts chemically or otherwise stably combines (e.g., by hybridization of two complimentary strands of nucleic acid) with the first patterning compound. See, e.g., Dubois and Nuzzo, Annu. Rev. Phys. Chem., 43, 437-63 (1992); Yan et al., J. Am. Chem. Soc., 120, 6179-6180 (1998); Yan et al., Langmuir, 15, 1208-1214 (1999); Lahiri et al., Langmuir, 15, 2055-2060 (1999); and Huck et al., Langmuir, 15, 6862-6867 (1999). As with DPN performed directly on a substrate, both the second patterning compound and a transport medium are necessary, since the second patterning compound is transported to the first patterning compound by capillary transport (see above). Third, fourth, etc., patterning compounds can also be applied to the first patterning compound, or to other patterning compounds, already on the substrate. Further, additional patterning compounds can be applied to form multiple layers of patterning compounds. Each of these additional patterning compounds may be the same or different than the other patterning compounds, and each of the multiple layers may be the same or different than the other layers and may be composed of one or more different patterning compounds. Further, DPN can be used in combination with other lithographic techniques. For instance, DPN can be used in conjunction with microcontact printing and the other lithographic techniques discussed in the Background section above. DPN can also be used in conjunction with wet (chemical) etching techniques. In particular, an SPM tip can be used to deliver a patterning compound to a substrate of interest in a pattern of interest, all as described above, and the patterning compound functions as an etching resist in one or more subsequent wet etching procedures. The patterning compounds can be used to pattern the substrate prior to any etching or after one or more etching steps have been performed to protect areas exposed by the etching step(s). The wet etching procedures and materials used in them are standard and well known in the art. See, e.g., Xia et al., Angew. Chem. Int. Ed., 37, 550 (1998); Xia et al., Chem. Mater., 7, 2332 (1995); Kumar et al., J. Am. Chem. Soc., 114, 9188-9189 (1992); Seidel et al., J. Electrochem. Soc., 137, 3612 (1990). Wet etching procedures are used for, e.g., the preparation of three-dimensional architectures on or in substrates (e.g., Si wafers),of interest. See, e.g., Xia et al., Angew. Chem. Int. Ed., 37, 550 (1998); Xia et al., Chem. Mater., 7, 2332 (1995). After, etching, the patterning compound may be retained on the substrate or removed from it. Methods of removing the patterning compounds from the substrates are well known in the art. See, e.g., Example 5. Several parameters affect the resolution of DPN, and its ultimate resolution is not yet clear. First, the grain size of the substrate affects DPN resolution much like the texture of paper controls the resolution of conventional writing. As shown in Example 1 below, DPN has been used to make lines 30 nm in width on a particular gold substrate. This size is the average grain diameter of the gold substrate, and it represents the resolution limit of DPN on this type of substrate. It is expected that better resolution will be obtained using smoother (smaller grain size) substrates, such as silicon. Indeed, using another, smoother gold substrate, the resolution was increased to 15 nm (see Example 4). Second, chemisorption, covalent attachment and self-assembly all act to limit diffusion of the molecules after deposition. In contrast, compounds, such as water, which do not anchor to the substrate, form only metastable patterns of poor resolution (See Piner et al., Langmuir, 13:6864 (1997)) and cannot be used. Third, the tip-substrate contact time and, thus, scan speed influence DPN resolution. Faster scan speeds and a smaller number of traces give narrower lines. Fourth, the rate of transport of the patterning compound from the tip to the substrate affects resolution. For instance, using water as the transport medium, it has been found that relative humidity affects the resolution of the lithographic process. For example, a 30-nm-wide line (FIG. 2C) required 5 minutes to generate in a 34% relative humidity environment, whereas a 100-nm-line (FIG. 2D) required 1.5 minutes to generate in a 42% relative humidity environment. It is known that the size of the water meniscus that bridges the tip and substrate depends upon relative humidity (Piner et al., Langmuir, 13:6864 (1997)), and the size of the water meniscus affects the rate of transport of the patterning compound to the substrate. Further, when a wet tip is used, the water meniscus contains residual solvent in the transport medium, and the transport rate is also affected by the properties of the solvent. Fifth, the sharpness of the tip also affects the resolution of DPN. Thus, it is expected That better resolution will be obtained using sharper tips (e.g., by changing the tips frequently, cleaning the tips before coating them, and attaching sharp structures (such as carbon nanotubes) to the ends of the tips). In summary, DPN is a simple but powerful method for transporting molecules from SPM tips to substrates at resolutions comparable to those achieved with much more expensive and sophisticated competitive lithographic methods, such as electron-beam lithography. DPN is a useful tool for creating and functionalizing microscale and nanoscale structures. For instance, DPN can be used in the fabrication of microsensors, microreactors, combinatorial arrays, micromechanical systems, microanalytical systems, biosurfaces, biomaterials, microelectronics, microoptical systems, and nanoelectronic devices. See, e.g., Xia and Whitesides, Angew. Chem. Int. Ed., 37, 550-575 (1998). DPN should be especially useful for the detailed functionalization of nanoscale devices prepared by more conventional lithographic methods. See Reed et al., Science, 278:252 (1997); Feldheim et al., Chem. Soc. Rev., 27:1 (1998). DPN, particularly parallel DPN, should also be especially useful for the preparation of arrays, particularly combinatorial arrays. An “array” is an arrangement of a plurality of discrete sample areas in a pattern on a substrate. The sample areas may be any shape.(e.g, dots, circles, squares or triangles) and may be arranged in any pattern (e.g., rows and columns of discrete sample areas). Each sample area may contain the same or a different sample as contained in the other sample areas of the array. A “combinatorial array” is an array wherein each sample area or a small group of replicate sample areas (usually 2-4) contain(s) a sample which is different than that found in other sample areas of the array. A “sample” is a material or combination of materials to be studied, identified, reacted, etc. DPN will be particularly useful for the preparation of combinatorial arrays on the submicrometer scale. An “array on the submicrometer scale” means that at least one of the dimensions (e.g, length, width or diameter) of the sample areas, excluding the depth, is less than 1 μm. At present, DPN can be used to prepare dots that are 10 nm in diameter. With improvements in tips (e.g., sharper tips), it should be possible to produce dots that approach 1 nm in diameter. Arrays on a submicrometer scale allow for faster reaction times and the use of less reagents than the currently-used microscale (i.e., having dimensions, other than depth, which are 1-999 μm) and larger arrays. Also, more information can be gained per unit area (i.e., the arrays are more dense than the currently-used micrometer scale arrays). Finally, the use of submicrometer arrays provides new opportunities for screening. For instance, such arrays can be screened with SPM's to look for physical changes in the patterns (e.g., shape, stickiness, height) and/or to identify chemicals present in the sample areas, including sequencing of nucleic acids (see below). Each sample area of an array contains a single sample. For instance, the sample may be a biological material, such as a nucleic acid (e.g., an oligonucleotide, DNA, or RNA), protein or peptide (e.g., an antibody or an enzyme), ligand (e.g., an antigen, enzyme substrate, receptor or the ligand for a receptor), or a combination or mixture of biological materials (e.g., a mixture of proteins). Such materials may be deposited directly on a desired substrate as described above (see the description of patterning compounds above). Alternatively, each sample area may contain a compound for capturing the biological material. See, e.g, PCT applications WO 00/04382, WO 00/04389 and WO 00/04390, the complete disclosures of which are incorporated herein by reference. For instance, patterning compounds terminating in certain functional groups (e.g., —COOH) can bind proteins through a functional group present on, or added to, the protein (e.g., —NH2). Also, it has been reported that polylysine, which can be attached to the substrate as described above, promotes the binding of cells to substrates. See James et al., Langmuir, 14, 741-744 (1998). As another example, each sample area may contain a chemical compound (organic, inorganic and composite materials) or a mixture of chemical compounds. Chemical compounds may be deposited directly on the substrate or may be attached through a functional group present on a patterning compound present in the sample area. As yet another example, each sample area may contain a type of microparticles or nanoparticles. See Example 7. From the foregoing, those skilled in the art will recognize that a patterning compound may comprise a sample or may be used to capture a sample. Arrays and methods of using them are known in the art. For instance, such arrays can be used for biological and chemical screenings to identify and/or quantitate a biological or chemical material (e.g., immunoassays, enzyme activity assays, genomics, and proteomics). Biological and chemical libraries of naturally-occurring or synthetic compounds and other materials, including cells, can be used, e.g., to identify and design or refine drug candidates, enzyme inhibitors, ligands for receptors, and receptors for ligands, and in genomics and proteomics. Arrays of microparticles and nanoparticles can be used for a variety of purposes (see Example 7). Arrays can also be used for studies of crystallization, etching (see Example 5), etc. References describing combinatorial arrays and other arrays and their uses include U.S. Pat. Nos. 5,747,334, 5,962,736, and 5,985,356, and PCT applications WO 96/31625, WO 99/31267, WO 00/04382, WO 00/04389, WO 00/04390,WO00/36136, and WO 00/46406. Results of experiments performed on the arrays of the invention can be detected by conventional means (e.g., fluorescence, chemiluminescence, bioluminescence, and radioactivity). Alternatively, an SPM can be used for screening arrays. For instance, an AFM can be used for quantitative imaging and identification of molecules, including the imaging and identification of chemical and biological molecules through the use of an SPM tip coated with a chemical or biomolecular identifier. See Frisbie et al., Science, 265, 2071-2074 (1994); Wilbur et al., Langmuir, 11, 825-831 (1995); Noy et al., J. Am. Chem. Soc., 117, 7943-7951 (1995); Noy et al., Langmuir, 14, 1508-1511 (1998); and U.S. Pat. Nos. 5,363,697, 5,372,93, 5,472,881 and 5,874,668, the complete disclosures of which are incorporated herein by reference. The present invention also includes novel components for more precisely depositing patterns on a substrate by DPN. In particular, the present invention includes a component that receives as input dot sizes and line widths of the patterning compound to be deposited on the substrate, and subsequently determines the corresponding parameter values that can be used in controlling the lower level software and hardware that deposits the substance on the substrate, e.g., such lower level software and hardware includes AFM systems. That is, since such lower level software and hardware (also denoted herein as AFM software and AFM hardware) typically are controlled by inputs such as “holding time” for stationarily depositing a dot of a desired size (e.g., diameter), and/or substrate drawing speed for depositing a line having a desired line width, the present invention includes a component for translating between: (a) dot size and line width, and (b) holding time and drawing speed, respectively. Moreover, since it is has been determined that dot size and line width are each a function of the diffusion rate of the patterning compound onto the substrate, the component for translating (also denoted a “pattern translator” or merely “translator” herein) translates between (a) and (b) above by using such diffusion rates. In particular, the applicants have determined that: (i) dot size may be determined according to the following equation:R=√{square root over (C*t/π)},where R is the radius of the dot, t is the holding time, and C is the diffusion constant, wherein C is, in turn, determined by the tip characteristics, the substrate, the patterning compound, and the contact force of the tip against the substrate; and (ii) line width may be determined according to the following equation:W=C/s,wherein W is the line width, s is the tip sweeping (e.g., drawing) speed, and C is as described above To more fully describe the components for performing the precision DPN of the present invention, reference is made to FIG. 28A which is a high level diagram of the DPN system 2004 of the present invention. Accordingly, this system includes a DPN geometry engine 2008 which provides a user interactive DNP application software components for allowing a user to interactively design DPN patterns. In one embodiment, the DNP. application components are provided on a WINDOWS 2000 platform by Microsoft Corp. More specifically, the DPN geometry engine 2008 includes the following modules: To more fully describe the components for performing the precision DPN of the present invention, reference is made to FIG. 28A which is a high level diagram of the DPN system 2004 of the present invention. Accordingly, this system includes a DPN geometry engine 2008 which provides a user interactive DNP application software components for allowing a user to interactively design DPN patterns. In one embodiment, the DNP application components are provided on a WINDOWS 2000 platform by Microsoft Corp. More specifically, the DPN geometry engine 2008 includes the following modules: (a) A computer aided design system 2012 (CAD) for generating at least two dimensional patterns. (b) A user interface 2016 for interacting with the computer aided design system, and for supplying information related specifically to the DPN process to be performed, such as, the identifications of the substrate, and the patterning compound to be deposited. Additionally, a user may be able to input tip characteristics such as tip shape, and tip materials, as well as an expected tip contact force against the substrate. Note that the user interface 2016 may provide graphical presentations to the user's display 2020. Alternatively, the user interface may receive input from a non-interactive source such a networked database (not shown). In one embodiment, the user may have multiple concurrent window presentations of his/her pattern or design. (c) A DPN runtime parameter storage 2024 for storing the DPN specific parameters such as the identification of the substrate and patterning compound, the tip characteristics, and contact force as in (b) immediately above. Patterns are output from the CAD 2012 to the pattern translator 2028 for translating into specifications of dots and piecewise linear shapes that can then be output to the drawing system 2030 which, e.g., may be an atomic force microscope system. In particular, this output is provided to the AFM software drivers 2032, wherein as mentioned above these drivers accept commands having values of holding time and drawing speed rather than dot size and line width. Additionally, the pattern translator 2028 also receives input from the DPN runtime parameter storage 2024 providing the parameter values identified in (c) above. Note that upon receiving the inputs from the CAD 2012 and the parameter storage 2024, the pattern translator 2028 may query a diffusion calibration database/expert system 2036 for the diffusion constant(s) C as described hereinabove. That is, the pattern translator 2028 uses the parameter values obtained from the parameter storage 2024 to query the diffusion calibration database/expert system 2036 for the corresponding diffusion constant(s) C that are to be applied to corresponding input from the CAD 2012. Subsequently, the pattern translator 2028 generates AFM commands for output to the AFM software drivers 2032, wherein each of the AFM commands is typically one of the following tip movement commands: (a) Keep the tip away from the substrate surface. (b) Hold the tip in contact with the substrate surface at a fixed position for a given time (t) with a given force. (c) Move the tip, while in contact with the substrate, in a line from a-first point to a second point at a given (fixed or variable) speed. Subsequently, the AFM software drivers 2032 direct the AFM hardware 2040 to apply the patterning compound to the substrate according to the commands received by the AFM software drivers 2032. Note that, for at least some of the AFM commands, the corresponding tip movement is in a range of approximately one nanometer to one hundred micrometers. However, dots provided by the present invention may be approximately one nanometer. Moreover, it is within the scope of the present invention that the AFM software drivers 2032 and the AFM hardware 2040 may utilize multiple drawing tips for drawing on the substrate. In particular, each drawing tip may use a different patterning compound (e.g., different ink). Note that the AFM software drivers 2032 may generate the tip controls for which of the multiple tips to use at any given time during a drawing of a pattern by the drawing system 2030. Note that the AFM software drivers 2032 can be commercially obtained from Thermomicroscopes, 9830 S. 51st Street, Suite A124 Phoenix, Ariz. 85044. Additionally, the AFM hardware can be obtained from Thermomicroscopes or one or more of the following companies: Veeco Inc., 112 Robin Hill Road, Santa Barbara, Calif. 93117, or Molecular Imaging Inc., 1171 Borregas Avenue, Sunnyvale, Calif. 94089. Additionally, note in an alternative embodiment, the diffusion rates may be empirically determined by the user, and accordingly, the diffusion calibration database/expert system 2036 may be unnecessary. Instead the user may enter the diffusion rates, e.g., via the user interface 2016. In FIG. 28B a high level flowchart is provided of the steps performed by the pattern translator 2028. In step 2054, the pattern translator 2028 receives a design (CAD) file from the CAD 2012. In step 2058, the pattern translator 2028 retrieves all corresponding DPN parameters for the DPN runtime parameter storage 2024. Note that, in one embodiment, there may be different such parameter values for different geometric data entities in the CAD file. Additionally, note that in another embodiment, the DPN parameter values may be provided in the CAD file and associated with their corresponding geometric entities. Further, in a simple case where such DPN parameter values are the same for all geometric entities, the DPN parameter values may occur in the CAD file only once wherein this occurrence is applicable to all geometric entities therein. Following this, in step 2062, a first geometric entity in the design file is obtained (denoted herein as “G”). Thus, in step 2066, the corresponding DPN parameter values are determined for G. Subsequently, in step 2070, the diffusion constant, CG, is obtained from the diffusion calibration database/expert system 2036. Note that as this database's name implies, it may be substantially a database (e.g., a relational database) that contains, e.g., a table associating a dot size, a patterning compound, a substrate, tip characteristics, and a contact force with a desired holding time for obtaining the dot size for the patterning compound on the substrate when the tip has the tip characteristics and the tip contacts the substrate surface with the contact force. Similarly, such a database will have a table associating a line width, a patterning compound, a substrate, tip characteristics, and a contact force with a desired holding time for obtaining the line width for a line of the patterning compound on the substrate when the tip has the tip characteristics and the tip contacts the substrate surface with the contact force. For example, the following is an illustration of entries in such a table: PatterningSub-DiffusionCompoundstrateTipContact forceconstant1-octa-goldMicro-1 nano newton 0.08 mm2/secdecanethiollever A16-mercapto-goldMicro-1 nano newton 0.04 mm2/sechexadecanoiclever AacidsilazaneSiliconMicro-1 nano newton0.005 mm2/secoxidelever AsilazaneGaAsMicro-1 nano newton0.003 mm2/seclever A Note, however, in some embodiments, such tables may be very large and/or not all combinations will have been previously determined (i.e., calibrated). Accordingly, where the invention embodiment is used with, e.g., various combinations of patterning compounds (e.g., different inks, or etching mask substances), and/or on various substrates, and/or where various types of tips may be used, the diffusion calibration database/expert system 2036 may intelligently compute, infer or interpolate a likely holding time and/or drawing speed. For example, a rule based expert system may be one embodiment of the diffusion calibration database/expert system 2036 for determining a likely diffusion constant. Additionally, note that when such a new a dot size and/or line width is verified for a particular patterning compound, substrate, tip characteristics, and contact force, then such values may be associated and stored for subsequent use by the diffusion calibration database/expert system 2036. In another alternative embodiment, instead of storing the diffusion constant, the holding times and drawing speeds may be associated with dot size and line width as well as the patterning compound, substrate, tip characteristics, and contact force. Referring again to FIG. 28B, in step 2074, the diffusion constant CG is used to determine a corresponding holding time and/or drawing speed for, respectively, each dot and piecewise linear portion of G. Thus, in step 2078, the pattern translator 2028 generates the AFM commands for drawing each portion of G and writes the generated AFM commands to an output file. Note, the software for generating sequences of AFM commands for drawing geometric entities is known to those skilled in the art, and such software is used in, e.g., dot matrix printers. Consequently, in step 2082, a determination is made as to whether there are additional geometric entities in the CAD file that need to be translated into AFM drawing commands. If so, then step 2062 is again encountered. Alternatively, step 2086 is performed, wherein the output file of AFM commands is provided as input to the AFM software drivers 2032. Note that further details regarding the pattern translator 2020 are provided in the APPENDIX hereinbelow. The invention also provides kits for performing DPN. In one embodiment, the kit comprises a container holding a patterning compound and instructions directing that the patterning compound be used to coat a scanning probe microscope tip and that the coated tip should be used to apply the patterning compound to the substrate so as to produce a desired pattern. This kit may further comprise a container holding a rinsing solvent, a scanning probe microscope tip, a substrate, or combinations thereof. In another embodiment, the kit comprises a scanning probe microsocpe tip coated with a patterning compound. This kit may further comprise a substrate, one or more containers, each holding a patterning compound or a rinsing solvent, or both. The substrates, tips, patterning compounds, and rinsing solvents are those described above. Any suitable container can be used, such as a vial, tube, jar, or a well or an array of wells. The kit may further comprise materials for forming a thin solid adhesion layer to enhance physisorption of the patterning compounds to the tips as described above (such as a container of titanium or chromium), materials useful for coating the tips with the patterning compounds (such as solvents for the patterning compounds or solid substrates for direct contact scanning), materials for performing lithography by methods other than DPN (see the Background section and references cited therein), and/or materials for wet etching. Finally, the kit may comprise other reagents and items useful for performing DPN or any other lithography method, such as reagents, beakers, vials, etc. The invention further provides an AFM adapted for performing DPN. In one embodiment, this microscope comprises a sample holder adapted for receiving and holding a substrate and at least one well holding a patterning compound, the well being positioned so that it will be adjacent the substrate when the substrate is placed in the sample holder and and so that it can be addressed by an SPM tip mounted on the AFM. The sample holder, wells and tips are described above. In another embodiment, the microscope comprises a plurality of scanning probe microscope tips and a tilt stage adapted for receiving and holding a sample holder, the sample holder being adapted for receiving and holding a substrate. The plurality of scanning probe microscope tips and the tilt stage are described above. As noted above, when an AFM is operated in air, water condenses between the tip and surface and then is transported by means of the capillary as the tip is scanned across the surface. This filled capillary, and the capillary force associated with it, significantly impede the operation of the AFM and substantially affect the imaging process. Quite surprisingly, it has been found that AFM tips coated with certain hydrophobic compounds exhibit an improved ability to image substrates in air by AFM as compared to uncoated tips. The reason for this is that the hydrophobic molecules reduce the size of the water meniscus formed and effectively reduce friction. As a consequence, the resolution of AFM in air is increased using a coated tip, as compared to using an uncoated tip. Accordingly, coating tips with the hydrophobic molecules can be utilized as a general pretreatment for AFM tips for performing AFM in air. Hydrophobic compounds useful for coating AFM tips, for performing AFM in air must form a uniform thin coating on the tip surface, must not bind covalently to the substrate being imaged or to the tip, must bind to the tip more strongly than to the substrate, and must stay solid at the temperature of AFM operation. Suitable hydrophobic compounds include those hydrophobic compounds described above for use as patterning compounds, provided that such hydrophobic patterning compounds are not used to coat AFM tips which are used to image a corresponding substrate for the patterning compound or to coat AFM tips which are made of, or coated with, materials useful as the corresponding substrate for the patterning compound. Preferred hydrophobic compounds for most substrates are those having the formula R4NH2, wherein R4 is an alkyl of the formula CH3(CH2)n or an aryl, and n is 0-30, preferably 10-20 (see discussion of patterning compounds above). Particularly preferred is 1-dodecylamine for AFM temperatures of operation below 74° F. (about 23.3° C.). AFM in air using any AFM tip may be improved by coating the AFM tip with the hydrophobic compounds described in the previous paragraph. Suitable AFM tips include those described above for use in DPN. AFM tips can be coated with the hydrophobic compounds in a variety of ways. Suitable methods include those described above for coating AFM tips with patterning compounds for use in DPN. Preferably, the AFM tip is coated with a hydrophobic compound by simply dipping the tip into a solution of the compound for a sufficient time to coat the tip and then drying the coated tip with an inert gas, all as described above for coating a tip with a patterning compound. After the tip is coated, AFM is performed in the same manner as it would be if the tip were not coated. No changes in AFM procedures have been found necessary. The transfer of 1-octadecanethiol (ODT) to gold (Au) surfaces is a system that has been studied extensively. See Bain et al., Angew. Chem. Int. Ed. Engl., 28:506 (1989); A. Ulman, An Introduction to Ultrathin Organic Films: From Langmuir-Blodgett to Self-Assembly (Academic Press, Boston, 1991); Dubois et al., Annu. Rev. Phys. Chem., 43:437 (1992); Bishop et al., Curr. Opin. Coll. Interf. Sci., 1:127 (1996); Alves et al., J. Am. Chem. Soc. 114:1222 (1992). Au having this moderately-air-stable molecule immobilized on it can be easily differentiated from unmodified Au by means of lateral force microscopy (LFM). When an AFM tip coated with ODT is brought into contact with a sample surface, the ODT flows from the tip to the sample by capillary action, much like a dip pen (FIG. 1). This process has been studied using a conventional AFM tip on thin film substrates that were prepared by thermally evaporating 300 Å of polycrystalline Au onto mica at room temperature. A Park Scientific Model CP AFM instrument was used to perform all experiments. The scanner was enclosed in a glass isolation chamber, and the relative humidity was measured with a hygrometer. All humidity measurements have an absolute error of ±5%. A silicon nitride tip (Park Scientific, Microlever A) was coated with ODT by dipping the cantilever into a saturated solution of ODT in acetonitrile for 1 minute. The cantilever was blown dry with compressed difluoroethane prior to use. A simple demonstration of the DPN process involved raster scanning a tip that was prepared in this manner across a 1 μm by 1 μm section of a Au substrate (FIG. 2A). An LFM image of this section within a larger scan area (3 μm by 3 μm) showed two areas of differing contrast (FIG. 2A). The interior dark area, or region of lower lateral force, was a deposited monolayer of ODT, and the exterior lighter area was bare Au. Formation of high-quality self-assembled monolayers (SAMs) occurred when the deposition process was carried out on Au(111)/mica, which was prepared by annealing the Au thin film substrates at 300° C. for 3 hours. Alves et al., J. Am. Chem. Soc., 114:1222 (1992). In this case, it was possible to obtain a lattice-resolved image of an ODT SAM (FIG. 2B). The hexagonal lattice parameter of 5.0±0.2 Å compares well with reported values for SAMs of ODT on Au(111) (Id.) and shows that ODT, rather than some other adsorbate (water or acetonitrile), was transported from the tip to the substrate. Although the experiments performed on Au(111)/mica provided important information about the chemical identity of the transported species in these experiments, Au(111)/mica is a poor substrate for DPN. The deep valleys around the small Au(111) facets make it difficult to draw long (micrometer) contiguous lines with nanometer widths. The nonannealed Au substrates are relatively rough (root-mean square roughness≅2 nm), but 30 nm lines could be deposited by DPN (FIG. 2C). This distance is the average Au grain diameter of the thin film substrates and represents the resolution limit of DPN on this type of substrate. The 30-nm molecule-based line prepared on this type of substrate was discontinuous and followed the grain edges of the Au. Smoother and more contiguous lines could be drawn by increasing the line width to 100 nm (FIG. 2D) or presumably by using a smoother Au substrate. The width of the line depends upon tip scan speed and rate of transport of the alkanethiol from the tip to the substrate (relative humidity can change the transport rate). Faster scan speeds and a smaller number of traces give narrower lines. DPN was also used to prepare molecular dot features to demonstrate the diffusion properties of the “ink” (FIGS. 3A and 3B). The ODT-coated tip was brought into contact (set point=1 nN) with the Au substrate for a set period of time. For example, 0.66 μm, 0.88 μm, and 1.6 μm diameter ODT dots were generated by holding the tip in contact with the surface for 2, 4, and 16 minutes, respectively (left to right, FIG. 3A). The uniform appearance of the dots likely reflects an even flow of ODT in all directions from the tip to the surface. Opposite contrast images were obtained by depositing dots of an alkanethiol derivative, 16-mercaptohexadecanoic acid in an analogous fashion (FIG. 3B). This not only provides additional evidence that the molecules are being transported from the tip to the surface but also demonstrates the molecular generality of DPN. Arrays and grids could be generated in addition to individual lines and dots. An array of twenty-five 0.46-μm diameter ODT dots spaced 0.54 μm apart (FIG. 3C) was generated by holding an ODT-coated tip in contact with the surface (1 nM) for 20 seconds at 45% relative humidity without lateral movement to form each dot. A grid consisting of eight intersecting lines 2 μm in length and 100 nm wide (FIG. 3D) was generated by sweeping the ODT-coated tip on a Au surface at a 4 μm per second scan speed with a 1 nN force for 1.5 minutes to form each line. A large number of compounds and substrates have been successfully utilized in DPN. They are listed below in Table 1, along with possible uses for the combinations of compounds and substrates. AFM tips (Park Scientific) were used. The tips were silicon tips, silicon nitride tips, and silicon nitride tips coated with a 10 nm layer of titanium to enhance physisorption of patterning compounds. The silicon nitride tips were coated with the titanium by vacuum deposition as described in Holland, Vacuum Deposition Of Thin Films (Wiley, New York, N.Y., 1956). It should be noted that coating the silicon nitride tips with titanium made the tips dull and decreased the resolution of DPN. However, titanium-coated tips are useful when water is used as the solvent for a patterning compound. DPN performed with uncoated silicon nitride tips gave the best resolution (as low as about 10 nm). Metal film substrates listed in Table 1 were prepared by vacuum deposition as described in Holland, Vacuum Deposition Of Thin Films (Wiley, New York, N.Y., 1956). Semidconductor substrates were obtained from Electronic Materials, Inc., Silicon Quest, Inc. MEMS Technology Applications Center, Inc., or Crystal Specialties, Inc. The patterning compounds listed in Table 1 were obtained from Aldrich Chemical Co. The solvents listed in Table 1 were obtained from Fisher Scientific. The AFM tips were coated with the patterning compounds as described in Example 1 (dipping in a solution of the patterning compound followed by drying with an inert gas), by vapor deposition or by direct contact scanning. The method of Example 1 gave the best results. Also, dipping and drying the tips multiple times further improved results. The tips were coated by vapor deposition as described in Sherman, Chemical Vapor Deposition For Microelectronics. Principles, Technology And Applications (Noyes, Park Ridges, N.J., 1987). Briefly, a patterning compound in pure form (solid or liquid, no solvent) was placed on a solid substrate (e.g., glassor silicon nitride; obtained from Fisher Scientific or MEMS Technology Application Center) in a closed chamber. For compounds which are oxidized by air, a vacuum chamber or a nitrogen-filled chamber was used. The AFM tip was position about 1-20 cm from the patterning compound, the distance depending on the amount of material and the chamber design. The compound was then heated to a temperature at which it vaporizes, thereby coating the tip with the compound. For instance, 1-octadecanethiol can be vapor deposited at 60° C. Coating the tips by vapor deposition produced thin, uniform layers of patterning compounds on the tips and gave quite reliable results for DPN. The tips were coated by direct contact scanning by depositing a drop of a saturated solution of the patterning compound on a solid substrate (e.g., glass or silicon nitride; obtained from Fisher Scientific or MEMS Technology Application Center). Upon drying, the patterning compound formed a microcrystalline phase on the substrate. To load the patterning compound on the AFM tip, the tip was scanned repeatedly (˜5 Hz scan speed) across this microcrystalline phase. While this method was simple, it did not lead to the best loading of the tip, since it was difficult to control the amount of patterning compound transferred from the substrate to the tip. DPN was performed as described in Example 1 using a Park Scientific AFM, Model CP, scanning speed 5-10 Hz. Scanning times ranged from 10 seconds to 5 minutes. Patterns prepared included grids, dots, letters, and rectangles. The width of the grid lines and the lines that formed the letters ranged from 15 nm to 250 nm, and the diameters of the individual dots ranged from 12 nm to 5 micrometers. TABLE 1PatterningPotentialSubstrateCompound/Solvent(s)ApplicationsComments and ReferencesAun-octadecanethiol/Basic researchStudy of intermolecular forces.acetonitrile, ethanolLangmuir, 10, 3315 (1994)Etching resist forEtchant: KCN/O2(pH-14).microfabricationJ. Vac. Sci. Tech. B, 13, 1139(1995)dodecanethiol/MolecularInsulating thin coating onacetonitrile, ethanolelectronicsnanometer scale gold clusters.Superlattices and Microstructures18, 275 (1995)n-hexadecanethiol/Etching resist forEtchant: KCN/O2(pH-14).acetonitrile, ethanolmicrofabricationLangmuir, 15, 300 (1999)n-docosanethiol/Etching resist forEtchant: KCN/O2(pH-14).acetonitrile, ethanolmicrofabricationJ. Vac. Sci. Technol. B, 13, 2846(1995)11-mercapto-1-SurfaceCapturing SiO2 clustersundecanol/functionalizationacetonitrile, ethanol16-mercapto-1-Basic researchStudy of intermolecular forces.hexadecanoic acid/Langmuir 14, 1508 (1998)acetonitrile, ethanolSurfaceCapturing SiO2, SnO2 clusters. J.functionalizationAm. Chem. Soc., 114, 5221(1992)octanedithiol/Basic researchStudy of intermolecular forces.acetonitrile, ethanolJpn. J. Appl. Phys. 37, L299(1998)hexanedithiol/SurfaceCapturing gold clusters. J. Am.acetonitrile, ethanolfunctionalizationChem. Soc., 114, 5221 (1992)propanedithiol/Basic researchStudy of intermolecular forces. J.acetonitrile, ethanolAm. Chem. Soc., 114, 5221(1992)α,α′-p-xylyldithiol/SurfaceCapturing gold clusters.acetonitrile, ethanolfunctionalizationScience, 272, 1323 (1996)MolecularConducting nanometer scaleelectronicsjunction.Science, 272, 1323 (1996)4,4′-biphenyldithiol/SurfaceCapturing gold and CdS clusters.acetonitrile, ethanolfunctionalizationInorganica Chemica Acta 242,115 (1996)terphenyldithiol/SurfaceCapturing gold and CdS clusters.acetonitrile, ethanolfunctionalizationInorganica Chemica Acta 242,115 (1996)terphenyldiisocyanide/SurfaceCapturing gold and CdS clusters.acetonitrile,functionalizationInorganica Chemica Acta 242,methylene chloride115 (1996)MolecularConductive coating on nanometerelectronicsscale gold clusters. Superlatticesand Microstructures, 18, 275(1995)DNA/Gene detectionDNA probe to detect biologicalwater:acetonitrile (1:3)cells.J. Am. Chem. Soc. 119, 8916(1997)Agn-hexadecanethiol/Etching resist forEtchant: Fe(NO3)3(pH-6).acetonitrile, ethanolmicrofabricationMicroelectron. Eng., 32, 255(1996)Al2-mercaptoacetic acid/SurfaceCapturing CdS clusters.acetonitrile, ethanolfunctionalizationJ. Am. Chem. Soc., 114, 5221(1992)GaAs-100n-octadecanethiol/Basic researchSelf assembled monolayeracetonitrile, ethanolformationEtching resist forHCl/HNO3(pH-1).microfabricationJ. Vac. Sci. Technol. B, 11, 2823(1993)TiO2n-octadecanethiol/Etching resist foracetonitrile, ethanolmicrofabricationSiO216-mercapto-1-SurfaceCapturing gold and CdS clustershexadecanoic acid/functionalizationacetonitrile, ethanoloctadecyltrichlorosilaneEtching resist forEtchant: HF/NH4F (pH-2).(OTS,microfabricationAppl. Phys. Lett., 70, 1593 (1997)CH3(CH2)17SiCl3)1.2 nm thick SAM/hexaneAPTS, 3-(2-SurfaceCapturing nanometer scale goldAminoethlyamino)propyltrimethoxysilane/functionalizationclusters.waterAppl. Phys. Lett. 70, 2759 (1997) As noted above, when an AFM is operated in air, water condenses between the tip and surface and then is transported by means of the capillary as the tip is scanned across the surface. Piner et al., Langmuir 13, 6864-6868 (1997). Notably, this filled capillary, and the capillary force associated with it, significantly impede the operation of the AFM, especially when run in lateral force mode. Noy et al., J. Am. Chem. Soc. 117, 7943-7951 (1995); Wilbur et al., Langmuir 11, 825-831 (1995). In air, the capillary force can be 10 times larger than chemical adhesion force between tip and sample. Therefore, the capillary force can substantially affect the structure of the sample and the imaging process. To make matters worse, the magnitude of this effect will depend on many variables, including the relative hydrophobicities of the tip and sample, the relative humidity, and the scan speed. For these reasons, many groups have chosen to work in solution cells where the effect can be made more uniform and reproducible. Frisbie et al., Science 265, 2071-2074 (1994); Noy et al., Langmuir 14, 1508-1511 (1998). This, however, imposes a large constraint on the use of an AFM, and solvent can affect the structure of the material being imaged. Vezenov et al., J. Am. Chem. Soc. 119, 2006-2015 (1997). Therefore, other methods that allow one to image in air with the capillary effect reduced or eliminated would be desirable. This example describes one such method. The method involves the modification of silicon nitride AFM tips with a physisorbed layer of 1-dodecylamine. Such tips improve one's ability to do LFM in air by substantially decreasing the capillary force and providing higher resolution, especially with soft materials. All data presented in this example were obtained with a Park Scientific Model CP AFM with a combined AFM/LFM head. Cantilevers (model no. MLCT-AUNM) were obtained from Park Scientific and had the following specifications: gold coated microlever, silicon nitride tip, cantilever A, spring constant=0.05N/m. The AFM was mounted in a Park vibration isolation chamber which had been modified with a dry nitrogen purge line. Also, an electronic hygrometer, placed inside the chamber, was used for humidity measurements (±5% with a range of 12˜100%). Muscovite green mica was obtained from Ted Pella, Inc. Soda lime glass microscope slides were obtained from Fisher. Polystyrene spheres with 0.23±0.002 μm diameters were purchased from Polysciences, and Si3N4 on silicon was obtained from MCNC MEMS Technology Applications Center. 1-Dodecylamine (99+%) was purchased from Aldrich Chemical Inc. and used without further purification. Acetonitrile (A.C.S. grade) was purchased from Fisher Scientific Instruments, Inc. Two methods for coating an AFM tip with 1-dodecylamine were explored. The first method involved saturating ethanol or acetonitrile with 1-dodecylamine and then depositing a droplet of this solution on a glass substrate. Upon drying, the 1-dodecylamine formed a microcrystalline phase on the glass substrate. To load the 1-dodecylamine on the AFM tip, the tip was scanned repeatedly (˜5 Hz scan speed) across this microcrystalline phase. While this method was simple, it did not lead to the best loading of the tip, since it was difficult to control the amount of 1-dodecylamine transferred from the substrate to the tip. A better method was to transfer the dodecylamine directly from solution to the AFM cantilever. This method involved soaking the AFM cantilever and tip in acetonitrile for several minutes in order to remove any residual contaminants on the tip. Then the tip was soaked in a ˜5 mM 1-dodecylamine/acetonitrile solution for approximately 30 seconds. Next, the tip was blown dry with compressed freon. Repeating this procedure several times typically gave the best results. The 1-dodecylamine is physisorbed, rather than chemisorbed, onto the silicon nitride tips. Indeed, the dodecylamine can be rinsed off the tip with acetonitrile as is the case with bulk silicon nitride. Benoit et al. Microbeam and Nanobeam Analysis; Springer Verlag, (1996). Modification of the tip in this manner significantly reduced the capillary effects due to atmospheric water condensation as evidenced by several experiments described below. First, a digital oscilloscope, directly connected to the lateral force detector of the AFM, was used to record the lateral force output as a function of time. In this experiment, the force of friction changed direction when the tip scanned left to right, as compared with right to left. Therefore, the output of the LFM detector switched polarity each time the tip scan direction changed. If one or more AFM raster scans were recorded, the output of the detector was in the form of a square wave, FIGS. 4A-B. The height of the square wave is directly proportional to the sliding friction of the tip on the sample and, therefore, one can compare the forces of friction between an unmodified tip and a glass substrate and between a modified tip and a glass substrate simply by comparing the height of the square waves under nearly identical scanning and environmental conditions. The tip/sample frictional force was at least a factor of three less for the modified tip than for the unmodified tip. This experiment was repeated on a mica substrate, and a similar reduction in friction was observed. In general, reductions in friction measured in this way and under these conditions ranged from a factor of three to more than a factor of ten less for the modified tips, depending upon substrate and environmental conditions, such as relative humidity. While this experiment showed that 1-dodecylamine treatment of an AFM tip lowered friction, it did not prove that water and the capillary force were the key factors. In another experiment, the effects of the 1-dodecylamine coating on the capillary transport of water was examined. Details of water transport involving unmodified tips have been discussed elsewhere. Piner et al., Langmuir 13, 6864-6868 (1997). When an AFM tip was scanned across a sample, it transported water to the sample by capillary action, FIG. 5A. After scanning a 4 μm×5 μm area of a soda glass substrate for several minutes, contiguous adlayers of water were deposited onto the substrate and imaged by LFM by increasing the scan size. Areas of lower friction, where water had been deposited, appeared darker than non-painted areas, FIG. 5A. The same experiment conducted with a tip coated with 1-dodecylamine did not show evidence of substantial water transport, FIG. 5B. Indeed, only random variations in friction were observed. While these experiments showed that friction could be reduced and the transport of water from the tip to the substrate by capillary action could be inhibited by coating the tip with 1-dodecylamine, they did not provide information about the resolving power of the modified tip. Mica is an excellent substrate to evaluate this issue and, indeed, lattice resolved images could be routinely obtained with the modified tips, demonstrating that this modification procedure reduced the force of friction without blunting the tip, FIG. 6A. It was impossible to determine whether the portion of the tip that was involved in the imaging was bare or had a layer of 1-dodecylamine on it. In fact, it is likely that the 1-dodecylamine layer had been mechanically removed from this part of the tip exposing the bare Si3N4. In any event, the remainder of the tip must have had a hydrophobic layer of dodecylamine on it, since water was inhibited from filling the capillary surrounding the point of contact, thereby reducing the capillary effect (see above). While the atomic scale imaging ability of the AFM was not adversely affected by the 1-dodecylamine coating on the tip, the above experiment did not provide useful information about the suitability of the tip for obtaining morphology data on a larger scale. In order to obtain such information, a sample of monodisperse 0.23 μm diameter latex spheres was imaged with both modified and unmodified tips. Since the topography recorded by an AFM is a convolution of the shape of the tip and the shape of the sample, any change in the shape of the tip will be reflected in a change in the imaged topography of the latex spheres. No detectable difference was found in images taken with unmodified and modified tips, respectively, FIGS. 7A-B. This shows that the shape of the tip was not significantly changed as it would be if a metallic coating had been evaporated onto it. Moreover, it suggests that the 1-dodecylamine coating was fairly uniform over the surface of the tip and was sharp enough that it did not adversely affect atomic scale imaging. A significant issue pertains to the performance of the modified tips in the imaging of soft materials. Typically, it is difficult to determine whether or not a chemically-modified tip exhibits improved performance as compared with a bare tip. This is because chemical modification is often an irreversible process which sometimes requires the deposition of an intermediary layer. However, since the modification process reported herein was based upon physisorbed layers of 1-dodecylamine, it was possible to compare the performance of a tip before modification, after modification, and after the tip had been rinsed and the 1-dodecylamine had been removed. Qualitatively, the 1-dodecylamine-modified tips always provided significant improvements in the imaging of monolayers based upon alkanethiols and organic crystals deposited onto a variety of substrates. For example, a lattice resolved image of a hydrophilic self-assembled monolayer of 11-mercapto-1-undecanol on a Au(111) surface was routinely obtained with a modified tip, FIG. 6B. The lattice could not be resolved with the same unmodified AFM tip. On this surface, the coated tip showed a reduction in friction of at least a factor of five by the square wave analysis (see above). It should be noted, that the OH-terminated SAM is hydrophilic and, hence, has a strong capillary attraction to a clean tip. Reducing the capillary force by the modified tip allows one to image the lattice. A second example of improved resolution involved imaging free standing liquid surfaces, such as water condensed on mica. It is well known that at humidities between 30 and 40 percent, water has two distinct phases on mica. Hu et al., Science 268, 267-269 (1995). In previous work by this group, a non-contact mode scanning polarization force microscope (SPFM) was used to image these phases. It was found that, when a probe tip came into contact with mica, strong capillary forces caused water to wet the tip and strongly disturbed the water condensate on the mica. To reduce the capillary effect so that two phases of water could be imaged, the tip was kept ˜20 nm away from the surface. Because of this constraint, one cannot image such phases with a contact mode scanning probe technique. FIGS. 6C-D show images of the two phases of water on mica recorded at 30 percent humidity with a 1-dodecylamine modified tip in contact mode. The heights of the features (FIG. 6C) corresponded with the frictional map (FIG. 6D), with higher features having lower friction. The quality of the modified tip, which it is believed correlates with the uniformity of the 1-dodecylamine layer on the tip, was important. Only well modified tips made it possible to image the two phases of water, while less well modified ones resulted in poorer quality images. In fact, this was such a sensitive test that it could be used as a diagnostic indicator of the quality of the 1-dodecylamine-modified tips before proceeding to other samples. In conclusion, this example describes a very simple, but extremely useful, method for making Si3N4 AFM tips hydrophobic. This modification procedure lowers the capillary force and improves the performance of the AFM in air. Significantly, it does not adversely affect the shape of the AFM tip and allows one to obtain lattice resolved images of hydrophilic substrates, including soft materials such as SAMs and even free-standing water, on a solid support. The development of methodology that allows one to get such information in air is extremely important because, although solution cells can reduce the effect of the capillary force, the structures of soft materials can be significantly affected by solvent. Vezenov et al., J. Am. Soc. 119, 2006-2015 (1997). Finally, although it might be possible to make an AFM tip more hydrophobic by first coating it with a metal layer and then derivatizing the metal layer with a hydrophobic chemisorbed organic monolayer, it is difficult to do so without concomitantly blunting the AFM tip. The inability to align nanoscale lithographically generated patterns comprised of chemically distinct materials is an issue that limits the advancement of both solid-state and molecule-based nanoelectronics. Reed et al., Science 278, 252 (1997); Feldheim, et al., Chem. Soc. Rev. 27, 1 (1998). The primary reasons for this problem are that many lithographic processes: 1) rely on masking or stamping procedures, 2) utilize resist layers, 3) are subject to significant thermal drift problems, and 4) rely on optical-based pattern alignment. Campbell, The Science and Engineering of Microelectronic Fabrication (Oxford Press); Chou et al., Appl. Phys. Lett. 67, 3114 (1995); Wang et al., Appl. Phys. Lett. 70, 1593 (1997); Jackman et al., Science 269, 664 (1995); Kim et al., Nature 376, 581 (1995); Schoer et al., Langmuir 13, 2323 (1997); Whelan et al., Appl. Phys. Lett. 69,4245 (1996); Younkin et al., Appl. Phys. Lett. 71, 1261 (1997); Bottomley, Anal. Chem. 70, 425R. (1998); Nyffenegger and Penner, Chem. Rev. 97, 1195 (1997); Berggren, et al., Science 269, 1255 (1995); Sondag-Huethorst et al., Appl. Phys. Lett. 64, 285 (1994); Schoer and Crooks, Langmuir 13, 2323 (1997); Xu and Liu, Langmuir 13, 127 (1997); Perkins, et al., Appl. Phys. Lett. 68, 550 (1996); Carr, et al., J. Vac. Sci. Technol. A 15, 1446 (1997); Sugimura et al., J. Vac. Sci. Technol. A 14, 1223 (1996); Komeda et al., J. Vac. Sci. Technol. A 16, 1680 (1998); Muller et al., J. Vac. Sci. Technol. B 13, 2846 (1995); and Kim and M. Lieber, Science 257, 375 (1992). With respect to feature size, resist-based optical methods allow one to reproducibly pattern many materials, soft or solid-state, in the >100 nm line width and spatial resolution regime, while e-beam lithography methods allow one to pattern in the 10-200 nm scale. In the case of soft-lithography, both e-beam lithography and optical methods rely on resist layers and the backfilling of etched areas with component molecules. This indirect patterning approach compromises the chemical purity of the structures generated and poses limitations on the types of materials that can be patterned. Moreover, when more than one material is being lithographically patterned, the optical-based pattern alignment methods used in these techniques limit their spatial resolution to approximately 100 nm. This example describes the generation of multicomponent nanostructures by DPN, and shows that patterns of two different soft materials can be generated by this technique with near-perfect alignment and 10 nm spatial resolution in an arbitrary manner. These results should open many avenues to those interested in molecule-based electronics to generate, align, and interface soft structures with each other and conventional macroscopically addressable microelectronic circuitry. Unless otherwise specified, DPN was performed on atomically flat Au(111) substrates using a conventional instrument (Park Scientific CP AFM) and cantilevers (Park Scientific Microlever A). The atomically flat Au(111) substrates were prepared by first heating a piece of mica at 120° C. in vacuum for 12 hours to remove possible water and then thermally evaporating 30 nm of gold onto the mica surface at 220° C. in vacuum. Using atomically flat Au(111) substrates, lines 15 nm in width can be deposited. To prevent piezo tube drift problems, a 100 μm scanner with closed loop scan control (Park Scientific) was used for all experiments. The patterning compound was coated on the tips as described in Example 1 (dipping in a solution) or by vapor deposition (for liquids and low-melting-point solids). Vapor deposition was performed by suspending the silicon nitride cantilever in a 100 mL reaction vessel 1 cm above the patterning compound (ODT). The system was closed, heated at 60 ° C. for 20 min, and then allowed to cool to room temperature prior to use of the coated tips. SEM analysis of tips before and after coating by dipping in a solution or by vapor deposition showed that the patterning compound uniformly coated the tips. The uniform coating on the tips allows one to deposit the patterning compound on a substrate in a controlled fashion, as well as to obtain high quality images. Since DPN allows one to image nanostructures with the same tool used to form them, there was the tantalizing prospect of generating nanostructures made of different soft materials with excellent registry. The basic idea for generating multiple patterns in registry by DPN is related to analogous strategies for generating multicomponent structures by e-beam lithography that rely on alignment marks. However, the DPN method has two distinct advantages, in that it does not make use of resists or optical methods for locating alignment marks. For example, using DPN, one can generate 15 nm diameter self-assembled monolayer (SAM) dots of 16-mercaptohexadecanoic acid (MHA) on a Au(111) faceted substrate (preparation same as described above for atomically flat Au(111) substrates) by holding an MHA-coated tip in contact (0.1 nN) with the Au(111) surface for ten seconds (see FIG. 9A). By increasing the scan size, the patterned dots are then imaged with the same tip by lateral force microscopy (LFM). Since the SAM and bare gold have very different wetting properties, LFM provides excellent contrast. Wilbur et al., Langmuir 11, 825 (1995). Based upon the position of the first pattern, the coordinates of additional patterns can be determined (see FIG. 9B), allowing for precise placement of a second pattern of MHA dots. Note the uniformity of the dots (FIG. 9A) and that the maximum misalignment of the first pattern with respect to the second pattern is less than 10 nm (see upper right edge of FIG. 9C). The elapsed time between generating the data in FIGS. 9A and 9C was 10 minutes, demonstrating that DPN, with proper control over environment, can be used to pattern organic monolayers with a spatial and pattern alignment resolution better than 10 nm under ambient conditions. This method for patterning with multiple patterning compounds required an additional modification of the experiment described above. Since the MHA SAM dot patterns were imaged with an tip coated with a patterning compound, it is likely that a small amount of undetectable patterning compound was deposited while imaging. This could significantly affect some applications of DPN, especially those dealing with electronic measurements on molecule-based structures. To overcome this problem, micron-scale alignment marks drawn with an MHA-coated tip (cross-hairs on FIG. 10A) were used to precisely place nanostructures in a pristine area on the Au substrate. In a typical experiment, an initial pattern of 50 nm parallel lines comprised of MHA and separated by 190 nm was prepared (see FIG. 10A). This pattern was 2 μm away from the exterior alignment marks. Note that an image of these lines was not taken to avoid contamination of the patterned area. The MHA-coated tip was then replaced with an ODT-coated tip. This tip was used to locate the alignment marks, and then precalculated coordinates based upon the position of the alignment marks (FIG. 10B) were used to pattern the substrate with a second set of 50 nm parallel ODT SAM lines (see FIG. 10C). Note that these lines were placed in interdigitated fashion and with near-perfect registry with respect to the first set of MHA SAM lines (see FIG. 10C). There is one unique capability of DPN referred to as “overwriting.” Overwriting involves generating one soft structure out of one type of patterning compound and then filling in with a second type of patterning compound by raster scanning across the original nanostructure. As a further proof-of concept experiment aimed at demonstrating the multiple-patterning-compound, high-registry, and overwriting capabilities of DPN over moderately large areas, a MHA-coated tip was used to generate three geometric structures (a triangle, a square, and a pentagon) with 100 nm line widths. The tip was then changed to an ODT-coated tip, and a 10 μm by 8.5 μm area that comprised the original nanostructures was overwritten with the ODT-coated tip by raster scanning 20 times across the substrate (contact force ˜0.1 nN) (dark areas of FIG. 11). Since water was used as the transport medium in these experiments, and the water solubilities of the patterning compounds used in these experiments are very low, there was essentially no detectable exchange between the molecules used to generate the nanostructure and the ones used to overwrite on the exposed gold (see FIG. 11). In summary, the high-resolution, multiple-patterning-compound registration capabilities of DPN have been demonstrated. On an atomically flat Au(111) surface, 15 nm patterns were generated with a spatial resolution better than 10 nm. Even on a rough surface such as amorphous gold, the spatial resolution was better than conventional photolithographic and e-beam lithographic methods for patterning soft materials. Lithographic techniques such as photolithography (Wallraff and Hinsberg, Chem. Rev., 99:1801 (1999)), electron beam lithography (Wallraff and Hinsberg, Chem. Rev., 99:1801 (1999); Xia et al., Chem. Rev., 99:1823 (1999)), and microcontact printing (Xia et al., Chem. Rev., 99:1823 (1999)) can be used with varying degrees of ease, resolution, and cost to generate three-dimensional features on silicon wafers. DPN is complementary to these other nanolithographic techniques and can be used with conventional laboratory instrumentation (an AFM) in routine fashion to generate patterns of, e.g., alkylthiols on polycrystalline gold substrates, under ambient conditions. Moreover, DPN offers 15 nm linewidth and 5 nm spatial resolution with conventional AFM cantilevers (see prior examples; Piner et al., Science, 283:661 (1999); Piner et al., Langmuir, 15:5457 (1999); Hong et al., Langmuir, 15:7897 (1999); Hong et al., Science, 286:523 (1999)). Three-dimensional architectures on and in silicon are vital to the microelectronics industry and, increasingly, are being applied to other uses in microfabrication (Xia and Whitesides, Angew, Chem. Int. Ed. Engl., 37:550 (1998)). For example, the anisotropic etching of silicon commonly yields narrow grooves, cantilevers, and thin membranes (Seidel et al., J. Electrochem. Soc., 137:3612 (1990)), which have been used for sensors of pressure, actuators, micro-optical components, and masks for submicron lithography techniques (Seidel et al., J. Electrochem. Soc., 137:3612 (1990)). For both the microeletronics applications and other microfabricated devices, significant advantages are expected from being able to make smaller feature sizes (Xia and Whitesides, Angew, Chem. Int. Ed. Engl., 37:550 (1998)). Additionally, the ability to fabricate smaller scale structures can lead to the discovery or realization of physical and chemical properties fundamentally different from those typically associated with larger structures. Examples include Coulomb blockades, single-electron tunneling, quantum size effects, catalytic response, and surface plasmon effects (Xia and Whitesides, Angew, Chem. Int. Ed. Engl., 37:550 (1998)). Therefore, a range of applications is envisioned for the custom-generated solid-state features potentially attainable through DPN and wet chemical etching. Consequently, the suitability of DPN-generated nanostructures as resists for generating three-dimensional multilayered solid-state structures by standard wet etching techniques was evaluated in a systematic study, the results of which are reported in this example. In this study, DPN was used to deposit alkylthiol monolayer resists on Au/Ti/Si substrates. Subsequent wet chemical etching yielded the targeted three-dimensional structures. Many spatially separated patterns of the monolayer resists can be deposited by DPN on a single Au/Ti/Si chip and, thus, the effects of etching conditions can be examined on multiple features in combinatorial fashion. As diagrammed in FIG. 12, in a typical experiment in this study, DPN was used to deposit alkylthiols onto an Au/Ti/Si substrate. It has been well established that alkylthiols form well-ordered monolayers on Au thin films that protect the underlying Au from dissolution during certain wet chemical etching procedures (Xia et al., Chem. Mater., 7:2332 (1995); Kumar et al., J. Am. Chem. Soc., 114:9188 (1992)), and this appears to also hold true for DPN-generated resists (see below). Thus, the Au, Ti, and SiO2 which were not protected by the monolayer could be removed by chemical etchants in a staged procedure (FIG. 12, panels b-e). This procedure yielded “first-stage” three-dimensional features: multilayer, Au-topped features on the Si substrate (FIG. 12, panel b). Furthermore, “second-stage” features were prepared by using the remaining Au as an etching resist to allow for selective etching of the exposed Si substrate (FIG. 12, panels c and d). Finally, the residual Au was removed to yield final-stage all-Si features, FIG. 12, panel e. Thus, DPN can be combined with wet chemical etching to yield three-dimensional features on Si(100) wafers with at least one dimension on the sub-100 nm length scale. Specifically, FIG. 12 diagrams the procedure used to prepare nanoscale features on Si wafers. First, polished single-crystalline Si(100) wafers were coated with 5 nm of Ti, followed by 10 nm of Au by thermal evaporation. The Si(100) wafers (4″ diameter (1-0-0) wafers; 3-4.9 ohm/cm resistivity; 500-550 μm thickness) were purchased from Silicon Quest International, Inc. (Santa Clara, Calif.). Thermal evaporation of 5 nm of Ti (99.99%; Alfa Aesar; Ward Hill, Mass.) followed by 10 nm of Au (99.99%; D. F. Goldsmith; Evanston, Ill.) was accomplished using an Edwards Auto306 Turbo Evaporator equipped with a turbopump (Model EXT510) and an Edwards FTM6 quartz crystal microbalance to determine film thickness. Au and Ti depositions were conducted at room temperature at a rate of 1 nm/second and a base pressure of <9×10−7 mb. After Au evaporation, the following procedure was performed on the substrates: a) DPN was used to deposit patterns of ODT, b) Au and Ti were etched from the regions not protected by the ODT monolayers using a previously reported ferri/ferrocyanide based etchant (Xia et al., Chem. Mater., 7:2332 (1995)), c) residual Ti and SiO2 were removed by immersing the sample into a 1% HF solution (note: this procedure also passivates the exposed Si surfaces with respect to native oxide growth) (Ohmi, J. Electrochem. Soc., 143:2957 (1996)), and d) the remaining Si was etched anisotropically by minor modifications of a previously reported basic etchant (Seidel et al., J. Electrochem. Soc., 137:3612 (1990)). The topography of the resulting wafers was evaluated by AFM and SEM. All DPN and all AFM imaging experiments were carried out with a Thermomicroscopes CP AFM and conventional cantilevers (Thermomicroscopes sharpened Microlever A, force constant=0.05 N/m, Si3N4). A contact force of 0.5 nN was typically used for DPN patterning. To minimize piezo tube drift problems, a 100-μm scanner with closed loop scan control was used for all of the experiments. For DPN, the tips were treated with ODT in the following fashion: 1) tips were soaked in 30% H2O2H2SO4 (3:7) (caution: this mixture reacts violently with organic material) for 30 minutes, 2) tips were rinsed with water, 3) tips were heated in an enclosed canister (approximately 15 cm3 internal volume) with 200 mg ODT at 60° C. for 30 minutes, and 4) tips were blown dry with compressed difluoroethane prior to use. Typical ambient imaging conditions were 30% humidity and 23° C., unless reported otherwise. Scanning electron microscopy (SEM) was performed using a Hitachi SEM equipped with EDS detector. A standard ferri/ferrocyanide etchant was prepared as previously reported (Xia et al., Chem. Mater., 7:2332 (1995)) with minor modification: 0.1 M Na2S2O3, 1.0 M KOH, 0.01 M K3Fe(CN)6, 0.001 M K4Fe(CN)6 in nanopure water. Au etching was accomplished by immersing the wafer in this solution for 2-5 minutes while stirring. The HF etchant (1% (v:v) solution in nanopure water) was prepared from 49% HF and substrates were agitated in this solution for 10 seconds. Silicon etching was accomplished by immersing the wafer in 4 M KOH in 15% (v:v) isopropanol in nanopure water at 55° C. for 10 seconds while stirring (Seidel et al., J. Electrochem. Soc., 137:3612 (1990)). Final passivation of the Si substrate with respect to SiO2 growth was achieved by immersing the samples in 1% HF for 10 seconds with mild agitation. Substrates were rinsed with nanopure water after each etching procedure. To remove residual Au, the substrates were cleaned in O2 plasma for 3 minutes and soaked in aqua regia (3:1 HCl:HNO3) for 1 minute, followed by immersing the samples in 1% HF for 10 seconds with mild agitation. FIG. 13A shows the AFM topography images of an Au/Ti/Si chip patterned according to the procedure outlined in FIG. 12, panels a-d. This image shows four pillars with a height of 55 nm formed by etching an Au/Ti/Si chip patterned with four equal-sized dots of ODT with center-to-center distances of 0.8 μm. Each ODT dot was deposited by holding the AFM tip in contact with the Au surface for 2 seconds. Although the sizes of the ODT dots were not measured prior to etching, their estimated diameters were approximately 100 nm. This estimate is based upon the measured sizes of ODT “test” patterns deposited with the same tip on the same surface immediately prior to deposition of the ODT dots corresponding to the shown pillars. The average diameter of the shown pillar tops was 90 nm with average base diameter of 240 nm. FIG. 13B shows a pillar (55 nm height, 45 nm top diameter, and 155 nm base diameter) from a similarly patterned and etched region on the same Au/Ti/Si substrate. The cross-sectional topography trace across the pillar diameter showed a flat top and symmetric sidewalls, FIG. 13C. The shape of the structure may be convoluted by the shape of the AFM tip approximately 10 nm radius of curvature), resulting in side widths as measured by AFM which may be larger than the actual widths. Additionally, an Au/Ti/Si substrate was patterned with three ODT lines drawn by DPN (0.4 μm/second, estimated width of each ODT line is 100 nm) with 1 μm center-to-center distances. FIG. 14A shows the AFM topography image after etching this substrate according to FIG. 12, panels a-d. The top and base widths are 65 nm and 415 nm, respectively, and line heights are 55 nm. FIG. 14B shows a line from a similarly patterned and etched region on the same Au/Ti/Si wafer, with a 50 nm top width, 155 nm base width, and 55 nm height. The cross-sectional topography trace across the line diameter shows a flat top and symmetric sidewalls (FIG. 14C). FIGS. 15 and 16 show the feature-size variation possible with this technique. In FIG. 15A, the ODT-coated AFM tip was held in contact with the surface for varying lengths of time (16-0.062 seconds) to generate various sized dots with 2 μm center-to-center distances which subsequently yielded etched three-dimensional structures with top diameters ranging from 1.47 μm to 147 nm and heights of 80 nm. The top diameters as measured by SEM differed by less than 15% from the diameters measured from the AFM images, compare FIGS. 15A and 15B. Additionally, energy dispersive spectroscopy (EDS) showed the presence of Au on the pillar tops whereas Au was not observed in the areas surrounding the elevated micro- and nanostructures. As expected, the diameters of the micro- and nano-trilayer structures correlated with the size of the DPN-generated resist features, which was directly related to tip-substrate contact time, FIG. 15C. Line structures were also fabricated in combinatorial fashion, FIG. 16. ODT lines were drawn at a scan rate varying from 0.2-2.8 μm/second with 1 μm center-to-center distances. After etching, these resists afforded trilayer structures, all with a height of 80 nm and top line widths ranging from 505 to 50 nm, FIG. 16. The field emission scanning electron micrograph of the patterned area looks comparable to the AFM image of the same area with the top widths as determined by the two techniques being within 15% of one another, compare FIGS. 16A and 16B. In conclusion, it has been demonstrated that DPN can be used to deposit monolayer-based resists with micron to sub-100 nm dimensions on the surfaces of Au/Ti/Si trilayer substrates. These resists can be used with wet chemical etchants to remove the unprotected substrate layers, resulting in three-dimensional solid-state feature with comparable dimensions. It is important to note that this example does not address the ultimate resolution of solid-state nanostructure fabrication by means of DPN. Indeed, it is believed that the feature size will decrease through the use of new “inks” and sharper “pens.” Finally, this work demonstrates the potential of using DPN to replace the complicated and more expensive hard lithography techniques (e.g. e-beam lithography) for a variety of solid-state nanolithography applications. The largest limitation in using scanning probe methodologies for doing ultra-high-resolution nanolithography over large areas derives from the serial nature of most of these techniques. For this reason, scanning probe lithography (SPL) methods have been primarily used as customization tools for preparing and studying academic curiosities (Snow et al., Appl. Phys. Lett., 75:1476 (1999); Luthi et al., Appl. Phys. Lett., 75:1314 (1999); Bottomley, Anal. Chem., 70:425R (1998); Schoer and Crooks, Langmuir, 13:2323 (1997); Xu and Liu, Langmuir, 13:127 (1997); Nyffenegger and Penner, Chem. Rev., 97:1195 (1997); Sugimur and Nakagiri, J. Vac. Sci. Technol. A, 14:1223 (1996); Muller et al., J. Vac. Sci. Technol. B, 13:2846 (1995); Jaschke and Butt, Langmuir, 11:1061 (1995); Kim and Lieber, Science, 257:375 (1992)). If SPL methodologies are ever to compete with optical or even stamping lithographic methods for patterning large areas (Xia et al., Chem. Rev., 99:1823 (1999); Jackman et al., Science, 269:664 (1995); Chou et al., Appl. Phys. Lett., 67:3114 (1995)), they must be converted from serial to parallel processes. Several important steps have been taken in this direction. For example, researchers have developed a variety of different scanning multiple probe instruments (Lutwyche et al., Sens. Actuators A, 73:89 (1999); Vettiger et al., Microelectron Eng., 46:11 (1999); Minne et al., Appl. Phys. Lett., 73:1742 (1998); Tsukamoto et al., Rev. Sci. Instrum., 62:1767 (1991)), and some have begun to use these instruments for parallel SPL. In particular, Quate and coworkers have shown that as many as 50 tips could be used at once (Minne et al., Appl. Phys. Lett., 73:1742 (1998)), and with such a strategy, both imaging and patterning speeds could be dramatically improved. However, a major limitation of all parallel SPL methods thus far developed is that each tip within the array needs a separate feedback system, which dramatically increases the instrumentation complexity and cost. One of the reasons separate feedback systems are required in such a process is that tip-substrate contact force influences the line width and quality of the patterned structure. Although parallel scanning tunneling microscope (STM) lithography has not yet been demonstrated, such a process would presumably require a feedback system for each tip that allows one to maintain constant tunneling currents. Like most other SPL methods, DPN thus far has been used exclusively in a serial format. Herein, a method for doing parallel or single pen soft nanolithography using an array of cantilevers and a conventional AFM with a single feedback system is reported. There is a key scientific observation that allows one to transform DPN from a serial to parallel process without substantially complicating the instrumentation required to do DPN. It has been discovered that features (e.g. dots and lines) generated from inks such as 1-octadecanethiol (ODT), under different contact forces that span a two-order of magnitude is range, are virtually identical with respect to diameter and line-width, respectively. Surprisingly, even patterning experiments conducted with a small negative contact force, where the AFM tip bends down to the surface, exhibit ink transport rates that are comparable to experiments executed with the tip-substrate contact force as large as 4 nN (FIG. 19). These experiments clearly showed that, in DPN writing, the ink molecules migrate from the tip through the meniscus to the substrate by diffusion, and the tip is simply directing molecular flow. The development of an eight pen nanoplotter capable of doing parallel DPN is described in this example. Significantly, since DPN line width and writing speed are independent of contact force, this has been accomplished in a configuration that uses a single tip feedback system to monitor a tip with dual imaging and writing capabilities (designated the “imaging tip”). In parallel writing mode, all other tips reproduce what occurs at the imaging tip in passive fashion. Experiments that demonstrate eight-pen parallel writing, ink and rinsing wells, and “molecular corralling” by means of a nanoplotter-generated structure are reported. All experiments were performed on a Thermomicroscopes M5 AFM equipped with a closed loop scanner that minimizes thermal drift. Custom DPN software (described above) was used to drive the instrument. The instrument has a 200 mm×200 mm sample holder and an automated translation stage. The intention in transforming DPN into a parallel process was to create an SPL method that allows one to generate multiple single-ink patterns in parallel or a single multiple-ink pattern in series. This tool would be the nanotechnologist's equivalent of a multiple-pen nanoplotter with parallel writing capabilities. To accomplish this goal, several modifications of the AFM and DPN process were required (see FIGS. 17 and 18). First, a tilt stage (purchased from Newport Corporation) was mounted on the translation stage of the AFM. The substrate to be patterned was placed in the sample holder, which was mounted on the tilt stage. This arrangement allows one to control the orientation of the substrate with respect to the ink coated tips which, in turn, allows one to selectively engage single or multiple tips during a patterning experiment (FIG. 17). Second, ink wells, which allow one to individually address and ink the pens in the nanoplotter, were fabricated. Specifically, it has been found that rectangular pieces of filter paper soaked with different inks or solvents can be used as ink wells and rinsing wells, respectively (FIG. 17). The filter-paper ink and rinsing wells were located on the translation stage proximate the substrate. An AFM tip can be coated with a molecular ink of interest or rinsed with a solvent simply by making contact with the appropriate filter-paper ink or rinsing well for 30 seconds (contact force=1 nN). Finally, a multiple tip array was fabricated simply by physically separating an array of cantilevers from a commercially available wafer block containing 250 individual cantilevers (Thermomicroscopes Sharpened Microlevers C, force constant=0.01 N/m), and then, using that array as a single cantilever (FIG. 18). The array was affixed to a ceramic tip carrier that comes with the commercially acquired mounted cantilevers and was mounted onto the AFM tip holder with epoxy glue (FIG. 18). For the sake of simplicity, experiments involving only, two cantilevers in the array will be described first. In parallel writing, one tip, designated “the imaging tip,” is used for both imaging and writing, while the second tip is used simply for writing. The imaging tip is used the way a normal AFM tip is used and is interfaced with force sensors providing feedback; the writing tips do not need feedback systems. In a patterning experiment, the imaging tip is used to determine overall surface topology, locate alignment marks generated by DPN, and lithographically pattern molecules in an area with coordinates defined with respect to the alignment marks (Example 4 and Hong et al., Science, 286:52 (1999)). With this strategy, the writing tip(s) reproduce the structure generated with the imaging tip at a distance determined by the spacing of the tips in the cantilever array (600 μm in the case of a two pen experiment). In a typical parallel, multiple-pen experiment involving a cantilever array, each tip was coated, with an ink by dipping it into the appropriate ink well. This was accomplished by moving the translation stage to position the desired ink well below the tip to be coated and lowering the tip until it touched the filter paper. Contact was maintained for 30 seconds, contact force=1 nN. To begin parallel patterning, the tilt stage was adjusted so that the writing tip was 0.4 μm closer to the sample than the imaging tip. The tip-to-sample distances in an array experiment can be monitored with the Z-stepper motor counter. The laser was placed on the imaging tip so that during patterning both tips were in contact with the surface (FIG. 17). The first demonstration of parallel writing involved two tips coated with the same ink, ODT (FIG. 20A). In this experiment, two one-molecule-thick nanostructures comprised of ODT were patterned onto a gold surface by moving the imaging tip along the surface in the form of a square (contact force ˜0.1 nN; relative humidity ˜30%; writing speed=0.6 μm/sec). Note that the line-widths are nearly identical and the nanostructure registration (orientation of the first square with respect to the second) is near-perfect. Parallel patterning can be accomplished with more than one ink. In this case the imaging tip was placed in a rinsing well to remove the ODT ink and then coated with 16-mercaptohexadecanoic acid (MHA) by immersing it in an MHA ink well. The parallel multiple-ink experiment was then carried out in a manner analogous to the parallel single ink experiment under virtually identical conditions. The two resulting nanostructures can be differentiated based upon lateral force but, again, are perfectly aligned due to the rigid, fixed nature of the two tips (FIG. 20B). Interestingly, the line-widths of the two patterns were identical. This likely is a coincidental result since feature size and line width in a DPN experiment often depend on the transport properties of the specific inks and ink loading. A remarkable feature of this type of nanoplotter is that, in addition to offering parallel writing capabilities, one can operate the system in serial fashion to generate customized nanostructures made of different inks. To demonstrate this capability, a cantilever array that had a tip coated with ODT and a tip coated with MHA was utilized. The laser was focused on the ODT coated tip, and the tilt stage was adjusted so that only this tip was in contact with the surface (FIG. 17). The ODT coated tip was then used to generate the vertical sides of a cross on a Au surface (contact force ˜0.1 nN; relative humidity ˜30%; writing speed=1.3 μm/second) (FIG. 21A). The laser was then moved to the MHA coated tip, and the tilt stage was readjusted so that only this tip was in contact with surface. The MHA tip was then used to draw the 30 nm wide horizontal sides of the nanostructure (“nano” refers to line width) (FIG. 21A). Microscopic ODT alignment marks deposited on the periphery of the area to be patterned were used to locate the initial nanostructure as described above (see also Example 4 and Hong et al., Science, 286:523 (1999)). This type of multiple ink nanostructure with a bare gold interior would be impossible to prepare by stamping methodologies or conventional nanolithography methods, but was prepared in five minutes with the multiple-pen nanoplotter. Moreover, this tool and these types of structures can now be used to begin evaluating important issues involving molecular diffusion on the nanometer length scale and across nanometer wide molecule-based barriers. As a proof-of-concept, the diffusion of MHA from a-tip to the surface within this type of “molecule-based corral” was examined. As a first step, a cross shape was generated with a single ink, ODT (contact force ˜0.1 nN; relative humidity ˜30%; writing speed=0.5 μm/second). Then, an MHA coated tip was held in contact with the surface for ten minutes at the center of the cross so that MHA molecules were transported onto the surface and could diffuse out from the point of contact. Importantly, even 80 nm wide ODT lines acted as a diffusion barrier, and MHA molecules were trapped inside the ODT cross pattern (FIG. 21B). When the horizontal sides of the molecular corral are comprised of MHA barriers, the MHA molecules diffuse from tip onto the surface and over the hydrophilic MHA barriers. Interestingly, in this two component nanostructure, the MHA does not go over the ODT barriers, resulting in an anisotropic pattern (FIG. 21C). Although it is not known yet if the corral is changing the shape of the meniscus, which in turn controls ink diffusion, or alternatively, the ink is deposited and then migrates from the point of contact to generate this structure, this type of proof-of-concept experiment shows how one can begin to discover and study important interfacial processes using this new nanotechnology tool. The parallel nanoplotting strategy reported herein is not limited to two tips. Indeed, it has been shown that a cantilever array consisting of eight tips can be used to generate nanostructures in parallel fashion. In this case, each of the eight tips was coated with ODT. The outermost tip was designated as the imaging tip and the feedback laser was focused on it during the writing experiment. To demonstrate this concept, four separate nanostructures. a 180 nm dot (contact force ˜0.1 nN, relative humidity=26%, contact time=1 second), a 40 nm wide line, a square and an octagon (contact force ˜0.1 nN, relative humidity ˜26%, writing speed=0.5 μm/second) were generated and reproduced in parallel fashion with the seven passively following tips (FIG. 22). Note that there is a less than 10% standard deviation in line width for the original nanostructures and the seven copies. In summary, DPN has been transformed from a serial to a parallel process and, through such work, the concept of a multiple-pen nanoplotter with both serial and parallel writing capabilities has been demonstrated. It is important to note that the number of pens that can be used in a parallel DPN experiment to passively reproduce nanostructures is not limited to eight. Indeed, there is no reason why the number of pens cannot be increased to hundreds or even a thousand pens without the need for additional feedback systems. Finally, this work will allow researchers in the biological, chemical, physics, and engineering communities to begin using DPN and conventional AFM instrumentation to do automated, large scale, moderately fast, high-resolution and alignment patterning of nanostructures for both fundamental science and technological applications. A general method for organizing micro- and nanoparticles on a substrate could facilitate the formation and study of photonic band gap materials, make it possible to generate particle arrays for analysis of the relationship between pattern structure and catalytic activity, and enable formation of single protein particle arrays for proteomics research. While several methods have been reported for assembling collections of particles onto patterned surfaces (van Blaaderen et al., Nature 385:321-323 (1997); Sastryet al., Langmuir 16:3553-3556 (2000); Tien et al., Langmuir 13:5349-5355 (1997); Chen et al., Langmuir 16:7825-7834 (2000); Vossmeyer et al., J. Appl. Phys. 84:3664-3670 (1998); Qin et al., Adv. Mater. 11:1433-1437 (1999)), a major challenge lies in the selective immobilization of single particles into pre-determined positions with respect to adjacent particles. A strategy for chemically and physically immobilizing a wide variety of particle types and sizes with a high degree of control over particle placement calls for a soft lithography technique capable of high-resolution patterning, but also with the ability to form patterns of one or more molecules with precision alignment registration. DPN is such a tool. This example demonstrates combinatorial arrays produced by DPN, focusing on the problem of particle assembly in the context of colloidal crystallization. Recently, conventional sedimentation methods for preparing colloidal crystals consisting of close-packed layers of polymer or inorganic particles (Park et al., Adv. Mater. 10:1028-1032 (1998), and references cited therein; Jiang et al., Chem. Mater. 11:2132-2140 (1999)) have been combined with polymer templates, fabricated by e-beam lithography, to form high quality single-component structures (van Blaaderen et al., Nature 385:321-323 (1997)). However, sedimentation or solvent evaporation routes do not offer the element of chemical control over particle placement. Herein, a DPN-based strategy for generating charged chemical templates to study the assembly of single particles into two-dimensional square lattices is described. The general method (outlined in FIG. 23) is to form a pattern on a substrate composed of an array of dots of an ink which will attract and bind a specific type of particle. For the present studies, MHA was used to make templates on a gold substrate, and positively-charged protonated amine- or amidine-modified polystyrene spheres were used as particle building blocks. Gold coated substrates were prepared as described in Example 5. For in situ imaging experiments requiring transparent substrates, glass coverslips (Corning No. 1 thickness, VWR, Chicago, Ill.) were cleaned with Ar/O2 plasma for 1 minute, then coated with 2 nm of Ti and 15 nm of Au. The unpattemed regions of the gold substrate were passivated by immersing the substrate in a 1 mM ethanolic solution of another alkanethiol, such as ODT or cystamine. Minimal, if any, exchange took place between the immobilized MHA molecules and the ODT or cystamine in solution during this treatment, as evidenced by lateral force microscopy of the substrate before and after treatment with ODT. The gold substrates were patterned with MHA to form arrays of dots. DPN patterning was carried out under ambient laboratory conditions (30% humidity, 23° C.) as described in Example 5. It is important to note that the carboxylic acid groups in the MHA patterns were deprotonated providing an electrostatic driving force for particle assembly. (Vezenov et al., J. Am. Chem. Soc. 119:2006-2015 (1997)) Suspensions of charged polystyrene latex particles in water were purchased from either Bangs Laboratories (0.93 μm, Fishers, IN) or IDC Latex (1.0 μm and 190 nm, Portland, Oreg.). Particles were rinsed free of surfactant by centrifugation and redispersion twice in distilled deionized water (18.1 MΩ) purified with a Barnstead (Dubuque, Iowa) NANOpure water system. Particle assembly on the substrate was accomplished by placing a 20 μl droplet of dispersed particles (10% wt/vol in deionized water) on the horizontal substrate in a humidity chamber (100% relative humidity). Gentle rinsing with deionized water completed the process. Optical microscopy was performed using the Park Scientific CP AFM optics (Thermomicroscopes, Sunnyvale, Calif.) or, for in situ imaging, an inverted optical microscope (Axiovert 100A, Carl Zeiss, Jena, Germany) operated in differential interference contrast mode (DIC). Images were captured with a Penguin 600 CL digital camera (Pixera, Los Gatos, Calif.). Intermittent-contact imaging of particles was performed with a Thermomicroscopes M5 AFM using silicon ultralevers (Thermomicroscopes, spring constant=3.2 N/m). Lateral force imaging was carried out under ambient laboratory conditions (30% humidity, 23° C.) and as previously reported (Weinberger et al., Adv. Mater. 12:1600-1603 (2000)). In a typical experiment involving 0.93 μm diameter particles, multiple templates were monitored simultaneously for particle assembly by optical microscopy. In these experiments, the template dot diameter was varied to search for optimal conditions for particle-template recognition, FIG. 24 (left to right). After 1 hour of particle assembly, the substrates were rinsed with deionized water, dried under ambient laboratory conditions, and then imaged by optical microscopy, FIG. 25. The combinatorial experiment revealed that the optimum size of the template pad with which to immobilize a single particle of this type in high registry with the pattern was approximately 500-750 nm. It is important to note that drying of the substrate tended to displace the particles from their preferred positions on the template, an effect that has been noted by others with larger scale experiments (Aizenberg et al., Phys. Rev. Lett. 84:2997-3000 (2000)). Indeed, evidence for better, in fact near-perfect, particle organization is obtained by in situ imaging of the surface after 1 μm amine-modified particles have reacted with the template for 1 hour, FIG. 26. Single particle spatial organization of particles on the micron length-scale has been achieved by physical means, for instance using optical tweezers (Mio et al., Langmuir 15:8565-8568 (1999)) or by sedimentation onto e-beam lithographically patterned polymer films (van Blaaderen et al., Nature 385:321-323 (1997)). However, the DPN-based method described here offers an advantage over previous methods because it provides flexibility of length scale and pattern type, as well as a means to achieve more robust particle array structures. For instance, DPN has been used to construct chemical templates which can be utilized to prepare square arrays of 190 nm diameter amidine-modified polystyrene particles. Screening of the dried particle arrays using non-contact AFM or SEM imaging revealed that 300 nm template dots of MHA, spaced 570 nm apart, with a surrounding repulsive monolayer of cystamine, were suitable for immobilizing single particles at each site in the array, FIG. 27A. However, MHA dots of diameter and spacing of 700 nm and 850 nm resulted in immobilization of multiple particles at some sites, FIG. 27B. Similar particle assembly experiments conducted at pH <5 or >9 resulted in random, non-selective particle adsorption, presumably due to protonation of the surface acid groups or deprotonation of particle amine or amidine groups. These experiments strongly suggested that the particle assembly process was induced by electrostatic interactions between charged particles and patterned regions of the substrate. In conclusion, it has been demonstrated that DPN can be used as a tool for generating combinatorial chemical templates with which to position single particles in two-dimensional arrays. The specific example of charged alkanethiols and latex particles described here will provide a general approach for creating two-dimensional templates for positioning subsequent particle layers in predefined crystalline structures that may be composed of single or multiple particle sizes and compositions. In a more general sense, the combinatorial DPN method will allow researchers to efficiently and quickly form patterned substrates with which to study particle-particle and particle-substrate interactions, whether the particles are the dielectric spheres which comprise certain photonic band-gap materials, metal, semiconductor particles with potential catalytic or electronic properties, or even living biological cells and macrobiomolecules. The program is written in the Microsoft Visual Basic. This Form_DPNWrite is a core subroutine of the pattern interpreter. The processes which should be done before the execution of the subroutine are: 1) Users should design patterns utilizing the user-interface subroutine. 2) The patterns designed by the users should be converted into series of dots and lines via well-known subroutines. The dots and lines should be saved in the variables, MyDot(i) and MyLine(i), respectively. 3) The diffusion constant C should be measured or retrieved from the table for the current tip, substrate, substance and environmental conditions, and it should be saved in the variable, Diffusion. The major functions of this subroutine are: 1) Calculate the holding time and speed for the basic patterns, dots and lines, respectively. 2) Save the corresponding command lines in the script file. 3) Ask the SPM software to run the script file to perform DPN writing. MyDot(i) is an array of DPNDot objects (class). Several important properties of the DPNDot object are X, Y, Size, HoldTime. MyDot(i) represents a dot pattern with a radius of MyDot(i). Size at the position of (MyDot(i).X, MyDot(i). Y). MyLine(i) is an array of DPNLine objects (class). Several important properties of the DPNLine objects are X1, Y1, X2, Y2, DPNWidth, Repeat, Speed. MyLine(i) represents a line pattern connecting between (X1, Y1) and (X2, Y2) with a linewidth of DPNWidth. Repeat is an optional parameter and its default value is 1. By specifying Repeat, users can specify whether the line will be drawn by one or multiple sweeps of the SPM tip. Program Starts Here: Public Sub Form_DPNWrite( ) ‘Calculate the holding time for each dot and save it in MyDot(i).HoldTime.’ For i=1 To MyDotNum MyDot(i).HoldTime=Round(3.14159*MyDot(i).Size*MyDot(i).Size/Diffusion, 5) Next i ‘Calculate the speed for each line and save it in MyLine(i).Speed.’ For i=1 To MyLineNum MyLine(i).Speed Round(Diffusion*MyLine(i).Repeat/MyLine(i).DPNWidth, 5) Next i ‘Create the script file which will store all the command lines which can be recognized by SPM software’ Open “c:\dpnwriting\nanoplot.scr” For Output As #1 ‘In the following lines, Command 1˜10 represent command lines specific for each commercial system for the drawing system 2030, and accordingly are dependent upon, e.g., the atomic force microscope system utilized as the drawing system. ‘Add the command for the SPM system initialization to the script file.’ Print #1, “Command 1: Set up the Drawing System.” Print #1, “Command 2: Separate the tip from the substrate.” ‘Add the commands for dot patterns to the script file.’ For i=1 To MyDotNum If MyDot(i).HoldTime >0 Then Print #1, “Command 3: Move the tip to the position of the dot.” Print #1, “Command 4: Approach the tip to make a contact with the substrate.” Print #1, “Command 5: Hold the tip for the period of MyDot(i).HoldTime.” End If Print #1, “Command 6: Separate the tip from the substrate.” Next i ‘Add the commands for line patterns to the script file.’ For i=1 To MyLineNum If MyLine(i).Speed >0 Then Print #1, “Command 7: Move the tip to the initial position, (X1, Y1)” Print #1, “Command 8: Approach the tip to make a contact with the substrate.” Print #1, “Command 9: Sweep the tip to (X2, Y2) with MyLine(i).Speed.” End If Print #1, “Command 10: Separate the tip from the substrate.” Next i Close #1 ‘Have the drawing system 2030 execute the commands in the script file.’ ‘The method to have the AFM software drivers 2032 run the script file depends on the commercial drawing system 2030 used. The following is one example where Shell Visual Basic function is utilized.’ Do_DPN=Shell(“c:\spmsoftware\spmsoftware.exe-x c:\dpnwriting\nanoplot.scr”, vbMinimizedFocus) End Sub |
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claims | 1. A fuel assembly comprising a plurality of fuel rods, each fuel rod containing a plurality of nuclear fuel pellets not requiring coatings, wherein at least one fuel pellet in more than 50% of said fuel rods in said fuel assembly comprises a sintered admixture consisting of UO2 and ZrB2. 2. The fuel assembly of claim 1, wherein said ZrB2 is present in said fuel pellet in an amount of about 5 ppm to about 5 wt %, based on the total amount of fuel in said fuel pellet. 3. The fuel assembly of claim 2, wherein boron of said ZrB2 is present in said fuel pellet in an amount of about 10 ppm to about 20,000 ppm, based on the total amount of fuel in said fuel pellet. 4. The fuel assembly of claim 1, wherein said ZrB2 in said at least one fuel pellet comprises enriched boron. 5. The fuel assembly of claim 4, wherein said enriched boron is enriched to a content of 10B greater than natural boron. 6. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 60% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2. 7. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 70% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 8. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 80% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 9. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 90% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 10. The fuel assembly of claim 1, wherein at least one fuel pellet in more than 50% and less than 90% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 11. The fuel assembly of claim 3, wherein the boron is 600 to 20000 ppm of the admixture. 12. A boiling water reactor having a fuel assembly, the fuel assembly comprising a plurality of fuel rods, each fuel rod containing a plurality of nuclear fuel pellets not requiring coatings, wherein at least one fuel pellet in more than 50% of said fuel rods in said fuel assembly comprises a sintered admixture consisting of UO2 and ZrB2. |
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abstract | The invention refers to a filter (1) for separating particle from cooling water in a nuclear plant, and a fuel assembly with such a filter. The filter has an inlet end (2) and an outlet end (3) and permits through-flow of the cooling water in a main flow direction (x). The filter includes a number of sheets (4) extending in the flow direction from the inlet end to the outlet end. The sheets are arranged beside each other and form passages for the cooling water. The sheets include a first portion (4′) extending from the inlet end (2), a second portion (4″) extending from the outlet end (3), and a third portion (4′″) extending between the first portion (4′) and the second portion (4″). The sheets (4) have along the first portion continuous wave-shape extending in a direction (y) transversally to the flow direction (x) and along the third portion a continuous wave-shape extending in the flow direction (x). |
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abstract | Radiation therapy systems and their components, including secondary radiation shields. At least some versions of the disclosed systems combine a radiation delivery device, a primary radiation shielding device, and a secondary shielding layer into an integrated, modular unit. This is accomplished by using a small direct beam shield capable of blocking a primary beam from a radiation delivery device. In turn, a thinner shielding layer can be used to surround the radiation delivery device and primary shielding device, enabling a single modular unit to be delivered to an installation site. In some embodiments, a bed may be disposed within the secondary shielding layer. In some embodiments, the system is configured to provide up to 4-pi (4π) steradians of radiation coverage to the bed from the radiation delivery device. |
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abstract | Provided are a method of controlling the compositional gradient and solubility of doped-additives at grain boundaries during sintering of a uranium-based oxide green pellet including the additives, and a method of manufacturing a sintered nuclear fuel pellet having a large grain size using the same. The grain boundary solubility of the doped-additives is maintained at a certain level by stepwise varying of an oxygen partial pressure during isothermal sintering of a uranium-based oxide green pellet including the additives. The method of manufacturing a sintered nuclear fuel pellet having a large grain size includes preparing additive mixed uranium oxide powder, forming an additive mixed uranium oxide green pellet using the mixed powder, heating the green pellet to a sintering temperature in a gas atmosphere having a low oxygen partial pressure, and sintering while a sintering gas atmosphere is changed to stepwise increase an oxygen partial pressure at the isothermal sintering temperature. |
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summary | ||
claims | 1. An arrangement for at least one of projective and tomographic phase-contrast imaging using X-ray radiation, comprising:at least one coherent or quasi-coherent X-ray source to generate a beam path;a measurement field in which an examination object is positionable;at least one one-dimensional phase grid with grid lines to generate an interference pattern, positioned in the beam path;a readout arrangement for the generated interference pattern, arranged downstream of the at least one one-dimensional phase grid, to detect a change in a frequency pattern during a phase scan; anda control and evaluation unit to determine gradient vectors of phase shift values for the phase scan, the phase shift values being aligned perpendicularly with respect to the longitudinal direction of the grid lines of the at least one one-dimensional phase grid and situated in the plane of the at least one one-dimensional phase grid, whereineach of the at least one X-ray source associated with one of the at least one one-dimensional phase grid and the readout arrangement being configured, relative to the examination object, to rotate about a system axis, and the at least one one-dimensional phase grid is arranged in the beam path such that, during a rotation of the at least one X-ray source, the examination object is scanned with different spatial orientations of the grid lines relative to the examination object. 2. The arrangement as claimed in claim 1, further comprising a gantry, wherein two X-ray sources of the at least one coherent or quasi-coherent X-ray sources are provided on the gantry and the associated one-dimensional phase grid of each X-ray source have a different angle of incidence (ζ1=90°−ξ1, ζ2=90°−ξ2) between its grid lines and the system axis projected thereon in the beam direction. 3. The arrangement as claimed in claim 2, wherein the two angles of incidence (ζ1=90°−ξ1, ζ2=90°−ξ2) are perpendicular with respect to each other. 4. The arrangement as claimed in claim 3, wherein the two angles of incidence (ζ1=90°−ξ1, ζ2=90°−ξ2)are 0° and 90°. 5. The arrangement as claimed in claim 2, wherein the two angles of incidence (ζ1=90°−ξ1, ζ2=90°−ξ2) are set such that the error in the reconstruction is minimized. 6. The arrangement as claimed in claim 1, wherein the at least one one-dimensional phase grid is arranged in a beam path from the at least one X-ray source and the at least one one-dimensional phase grid has an angle of incidence (ζ=90°−ξ) between its grid lines and the system axis projected thereon in the beam direction which does not equal an integer multiple of a right angle. 7. The arrangement as claimed in claim 6, wherein the angle of incidence (ζ=90°−ξ) lies between 10° and 80°. 8. The arrangement as claimed in claim 7, wherein the angle of incidence (ζ=90°−ξ) lies between 30° and 60°. 9. The arrangement as claimed in claim 8, wherein the angle of incidence is 45°. 10. The arrangement as claimed in claim 6, wherein the angle of incidence (ζ=90°−ξ) is selected such that the error in the reconstruction is minimized. 11. The arrangement as claimed in claim 1, wherein the readout arrangement comprises an analysis grid and an at least single-row detector. 12. The arrangement as claimed in claim 1, wherein the readout arrangement comprises a detector which has a multiplicity of strip-shaped detection strips which can be read out individually aligned with the grid lines of the at least one one-dimensional phase grid for each of the multiplicity of strip-shaped detection strips. 13. The arrangement as claimed in claim 1, wherein the at least one X-ray source is configured as an almost punctiform source. 14. The arrangement as claimed in claim 1, further comprising:a source grid for generating quasi-coherent radiation is arranged in the beam path between the at least one X-ray source and the at least one one-dimensional phase grid. 15. A method for generating at least one of projective and tomographic image data records with differential phase contrast using X-ray radiation, comprising:scanning on a projection axis an examination object with at least one coherent or quasi-coherent X-ray source and at least one one-dimensional phase grid arranged in a beam path, wherein at least two phase scans with a respectively differently oriented phase grid of the at least one one-dimensional phase grids are performed for the projection axis;determining gradient vectors of phase shift values for each of the at least two phase scans, the phase shift values being aligned perpendicularly with respect to the longitudinal direction of grid lines of the at least one one-dimensional phase grid and situated in the plane of the at least one one-dimensional phase grid; andcalculating gradient vectors of the phase shift values, with magnitude and direction in the plane of the at least one one-dimensional phase grid, from the at least two phase scans of the projection axis. 16. The method as claimed in claim 15, wherein local phase shift values are calculated from the gradient vectors by integrating line integrals. 17. The method as claimed in claim 16, wherein the local phase shift values are determined for a plurality of projection angles over at least 180° and that computed tomography image data is reconstructed from this projection data. 18. The method as claimed in claim 15, wherein local phase shift values are determined for a plurality of projection angles over at least 180° and that computed tomography image data is reconstructed from projection data associated with the local phase shift values. 19. The method as claimed in claim 15, wherein there are, for the projection axis, two phase scans in opposing directions using the X-ray source, phase grid and readout arrangement, with the system respectively being rotated by 180° around a system axis. 20. A method for generating at least one of projective and tomographic image data records with differential phase contrast using X-ray radiation, comprising:scanning, on a projection axis, an examination object with at least one coherent or quasi-coherent X-ray source and at least one one-dimensional phase grid arranged in a beam path, wherein at least two phase scans with a respectively differently oriented phase grid are performed for the projection axis;determining gradient vectors of phase shift values for each of the at least two phase scans, the phase shift values being aligned perpendicularly with respect to the longitudinal direction of grid lines of the at least one one-dimensional phase grid and situated in the plane of the at least one one-dimensional phase grid; andreconstructing tomographic local phase shift values directly from the determined gradient vectors. 21. The method as claimed in claim 20, wherein the reconstruction is performed directly using the two gradient vectors measured perpendicularly with respect to the grid lines of the at least one one-dimensional phase grid. 22. The method as claimed in claim 20, wherein the gradient vectors with magnitude and direction are calculated before the reconstruction from the two gradient vectors measured perpendicularly with respect to the grid lines of the at least one phase grid and wherein the reconstruction is performed therewith. 23. The method as claimed in claim 20, wherein for the projection axis there are two phase scans in opposing directions using the X-ray source, the at least one one-dimensional phase grid and readout arrangement, with the system respectively being rotated by 180° around a system axis. 24. A method for generating at least one of projective and tomographic image data records with differential phase contrast using X-ray radiation, using an arrangement as claimed in claim 1, the method comprising:scanning on a projection axis an examination object with at least one coherent or quasi-coherent X-ray source and at least one one-dimensional phase grid arranged in a beam path, wherein at least two phase scans with a respectively differently oriented phase grid are performed for the projection axis;determining gradient vectors of phase shift values for each of the at least two phase scans, the phase shift values being aligned perpendicularly with respect to the longitudinal direction of grid lines of the at least one one-dimensional phase grid and situated in the plane of the at least one one-dimensional phase grid; andcalculating gradient vectors of the phase shift values, with magnitude and direction in the plane of the at least one one-dimensional phase grid, from the at least two phase scans of the projection axis. 25. A method for generating at least one of projective and tomographic image data records with differential phase contrast using X-ray radiation, using an arrangement as claimed in claim 1, the method comprising:scanning, on a projection axis, an examination object with at least one coherent or quasi-coherent X-ray source and at least one one-dimensional phase grid arranged in a beam path, wherein at least two phase scans with a respectively differently oriented phase grid are performed for the projection axis;determining gradient vectors of phase shift values for each of the at least two phase scans, the phase shift values being aligned perpendicularly with respect to the longitudinal direction of grid lines of the at least one one-dimensional phase grid and situated in the plane of the at least one one-dimensional phase grid; andreconstructing tomographic local phase shift values directly from the determined gradient vectors. 26. A non-transitory computer readable medium including program segments for, when executed on a computer device, causing the computer device to implement the method of claim 15. 27. A non-transitory computer readable medium including program segments for, when executed on a computer device, causing the computer device to implement the method of claim 20. |
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042279674 | claims | 1. Apparatus for controlling the power level in a nuclear reactor, said reactor having a core that is cooled during normal operation by a flow of primary coolant, comprising: (a) an elongate absorber support shaft adapted for relative motion with respect to the core of a nuclear reactor; (b) an elongate absorber member for absorbing neutrons in the nuclear reactor, said member being adapted for relative motion with respect to the core of the reactor; and (c) a plurality of high coefficient thermal expansion members and a corresponding plurality of low coefficient thermal expansion members disposed in alternate relationship and connected in series alternately at their top ends and at their bottom ends, said expansion members being elongate and attached at one end of the alternating series to the absorber support shaft and at the other end of the series to the absorber member so that the absorber support shaft, absorber member, and thermal expansion members all have longitudinal axes oriented in a direction generally parallel to the direction of relative motion between the absorber member and the core and together form an elongate in-line structure, the absorber member being moved relative to the core by the motion of the absorber support shaft and by thermal elongation of the expansion members, the absorber member being movable by thermal elongation relative to the absorber support shaft into closer proximity with the core as the temperature of the core increases, said thermal expansion members being in thermal communication with the core and responsive to the temperature thereof. (a) supporting a neutron absorber member in a nuclear reactor for absorbing neutrons therein using a control rod drive shaft and a plurality of alternately connected members having high coefficients and low coefficients of thermal expansion; (b) controlling the power level in the reactor on command by relatively moving the neutron absorber member with respect to the core using a rod drive motor to move the rod drive shaft and the thermal expansion members; and (c) moving the neutron absorber member with respect to the rod drive shaft and in turn with respect to the core in a manner responsive to the reactor core temperature by using the thermal expansion properties of the thermal expansion members and controlling the power level in the reactor using the absorber member independently of and in addition to the motion of the rod drive shaft so that as the core temperature increases, the power level is correspondingly decreased. 2. Apparatus as in claim 1 in which the thermal expansion members are a plurality of coaxial cylinders of differing radii and are attached together in an alternating manner, each cylinder having a principal axis oriented parallel to the direction of relative motion and co-incident with the longitudinal axis of the absorber support shaft. 3. Apparatus as in claim 1 in which the thermal expansion members are a plurality of parallel rods that are connected by a mechanical yoke so that thermal expansion of the members is amplified in the direction of relative motion, each rod having a principal axis oriented parallel to the direction of relative motion. 4. Apparatus as in claim 1 in which the nuclear reactor is a liquid metal fast breeder reactor and the plurality of high and low coefficient thermal expansion members provides a negative temperature coefficient of reactivity to said reactor so that the rate at which neutrons are absorbed increases proportionally as the temperature of the liquid metal primary coolant increases and the power level is correspondingly decreased. 5. Method for controlling the power level in a nuclear reactor, said reactor having a core that is cooled during normal operation by a flow of primary coolant, comprising the steps of: |
description | This application claims priority to provisional application No. 62/072,819, filed Oct. 30, 2014. The invention pertains to a method and system for monitoring building environmental data and generating data reports from a sensors and thermostats via a remote input device. The controls for thermostats increasingly provide more programming options, as the sophistication of the thermostat functionality expands. As a result, more data points are available regarding the performance of such high-tech thermostats. Capturing and outputting such data allows users of such equipment to more carefully control the environment and plan and predict the results of potential changes in temperature and humidity. Therefore, there is desired a method and system for outputting data regarding the performance of a thermostat and interconnected heating and cooling equipment. An embodiment of the invention provides for a method for compiling building environmental data comprising the steps of providing sensors located in the building, the sensors for collecting environmental data including at least one of: indoor temperature, outdoor temperature, humidity, occupancy, smoke, CO2, thermostat data including setpoints, fan on/off states, heating on/off states, cooling on/off states and room location, organizing performance data (PD) from a controller based on the environmental data received from the sensors, formatting the performance data and creating a PD report wherein the user selects at least one of summary data, detail data or all data and transmitting the PD report to a remote device. In an embodiment the PD report is transmitted to a registered user. Wherein the report may be formatted by selecting from a 24 hour, seventy-two hour, seven day or thirty day period duration during which the performance data is collected. Wherein the PD report may be sent based on one of the following intervals: daily, weekly and monthly. In an embodiment the method wherein the PD report may be formatted by at least one of: summary data, detail data or all data. The PD report may be used as a room source one of a basement, downstairs, family room, home office, kitchen or bedrooms. The PD report may provide for input of dealer information. The PD report may be generated directly following input of user information or user settings. The PD report may be generated at a time remote from and subsequent to the entry of the user information or user settings. The user may select from preselected data. Another embodiment of the invention provides for a system for generating a performance data (PD) report comprising a first module for collecting performance data a second module for formatting the PD and selecting from at least one of the following formats: summary data, detail data, all data, system run time in minutes, heat run time in minutes, cooling run time in minutes, fan run time in minutes, average heating temperature by degrees, average cooling temperature by degrees, average outdoor temperature by degrees, average humidity level by percent humidity, highest indoor temperature by degrees, lowest indoor temperature by degrees, highest outdoor temperature by degrees, lowest indoor temperature by degrees, highest humidity level by percent humidity and lowest percent humidity by percent humidity, date, time, system mode, such as cool or heat or a fan, system state, room temperature, setpoint, fan state, outdoor temperature and humidity level (collectively hereinafter “custom Performance Data”). In an embodiment the system provides a custom PD report is transmitted to a registered user. The report may be formatted by selecting from a twenty-four hour, seventy-two hour, seven day or thirty day period duration during which the performance data is collected. The custom PD report may be sent based on one of the following intervals: daily, weekly and monthly. The custom PD report may have a format including: summary, detailed or all data. The report may use as a room source one of a basement, downstairs, family room, home office, kitchen or bedrooms. The custom PD report may provide for input of dealer information. The custom PD report may be generated at a time directly following the entry of the user input. The custom PD report may be generated at a time remote from and subsequent to the entry of the user input. In another embodiment, a system for generating building environmental data is provided comprising a first module for collecting building environmental data, a second module for formatting the environmental data and transmitting the environmental data to a remote input device of a registered user. The environmental data may be selected from a twenty-four hour, seventy-two hour, seven day or thirty day period, during which the data is collected. The above drawing figures depict only embodiments which are presently preferred and the invention is not limited to such disclosed embodiments or the precise arrangement and instrumentality shown. The present invention is described with respect to FIGS. 1-9. Turning to FIG. 1, a flow diagram is provided which depicts the operation of the invention during a first operation including set up of the reporting parameters in steps 100-115; and a subsequent operation with steps 120-126. The invention provides for output of performance data for a thermostat or other HVAC control. Data may include the following types of data: system run time in minutes, heat run time in minutes, cooling run time in minutes, fan run time in minutes, average heating temperature by degrees, average cooling temperature by degrees, average outdoor temperature by degrees, average humidity level by percent humidity, highest indoor temperature by degrees, lowest indoor temperature by degrees, highest outdoor temperature by degrees, lowest indoor temperature by degrees, highest humidity level by percent humidity and lowest percent humidity by percent humidity, date, time, system mode, such as cool or heat or a fan, system state, room temperature, setpoint, fan state, outdoor temperature and humidity level (collectively hereinafter “Performance Data”). Other data may be collected including service information to repair or update equipment such as furnaces, HVAC, fans, thermostats, sensors, wireless communications for equipment and appliances, power consumption data, power outages/surges, alarms, open/closed windows and doors, electronic utility data, water consumption, gas consumption, time of sunset/sunrise, or high winds. In an embodiment, the method starts at step 100 (FIG. 1) with the first iteration and initial set-up of the system. The application is loaded on a remote device at step 101, for example a tablet or smartphone 10 (FIG. 2). At step 102 authentication credentials are provided by inputting them to the remote device 10. For example, the remote device may have a screen such as a touchpad screen 15, 213 (FIG. 2) for entering the data. For example, in FIG. 3 at step 103 (FIG. 1), a party wishes to receive a Performance Data report. The equipment for the report is maintained by Bob's Service Company and the set-up data for the service company is has been entered into screen 15 of the smartphone 10 at fields for Name 22, Phone 24, E-mail 26 and Website 28. To modify the dealer's information, the Update Dealer button 30 is touched. At step 104, the report is created by clicking on the button “Smart Data report” button 32 in FIG. 3. At step 105, the device (e.g. thermostat, indoor temperature sensor, outdoor temperature sensor, occupancy sensor, etc.) from which a Performance Data report is desired is selected by scrolling up or down on a list presented on the screen 15 of the smartphone 10 (FIG. 4). In an embodiment, the options of family room 34, basement 36, downstairs 38, office 40, and home office 42 are provided; from which the thermostat in any of those rooms may be selected. In an alternate embodiment, other rooms may be listed including: master bedroom, kids' bedroom, pool, shipping dock, storage room, factory processing area, etc. Once the desired location of the thermostat is selected at step 105, the preferential device is saved to the report by touching the “enter” button 44. At step 106, the predetermined time period may be selected by touching the report options screen 15 of the smartphone (FIG. 2). Among the options are one or two days for reporting. In other embodiments, a button 46 may be provided for providing a one day reporting period (24 Hours button) 46; a two day button 48 (or alternatively a 72 hour button), a Seven Days button 50 and Thirty Days button 52 (FIG. 5). In a further alternative, as shown in FIG. 1, step 106, a period of 1, 2, 7 or 30, rolling days, may be provided for the Performance Data report. At step 106 the preferred time period is saved by touching the “enter” button 44 (FIG. 5) on the screen 15. At step 107 the selection of reporting just a summary 54, included details 56, or all 58 (FIG. 6) may be selected by pressing the appropriate button on the screen 15, and those selections may be saved to step 112 (FIG. 1). In an alternate step, as shown in FIG. 10, Auto Report Features may be selected including time durations of Daily, Weekly or Monthly by pressing buttons 61, 62, 63, respectively. The user may then select Summary, Detail or All by selecting buttons 65, 66, 67, respectively in FIG. 6. At FIG. 7 a confirmation of the sending of the performance data and environmental data report may be sent, such a message that states, “Auto report setting saved. Your report will be sent on July 1.” (such date calculated based on when the report would be sent). At step 108, the report may be sent by clicking on the appropriate “send” button. After that step, the screen 59 will provide a pop-up window that states “Report sent to account e-mail.” (FIG. 7.) At step 109, a Performance Data report may be generated that is stored as snapshot and transitional data and customer report preferences. The user may use the smartphone 10 to access his or her e-mail account where the Performance Data report from the thermostat has been sent and the user may save or access the report accordingly. For example, at step 113 the report may be formatted and e-mailed. At step 114 the data report that was sent from the thermostat or other controller connected to the HVAC may be confirmed as successfully sent. As well, the report may be printed if the device receiving the report is connected to a printer according to a well-known protocol at step 115. In subsequent iterations, where a report is required but the user preferences and settings were previously input, or the default settings are sufficient, the process starts at step 120 (FIG. 1). At step 121 the user is reminded to “Navigate to Create Report Entity Screen.” On the mobile device 10 a button is displayed on the screen 15 and identifies the data report system. For example, on many smart phones; a list of applications are provided or icons for the applications are displayed on the screen 15. The appropriate icon is activated/clicked at step 122 and a window will appear that provides for a “Quick Report” button 60 (FIG. 5). The “Quick Report” button 60 is clicked to send the report at step 123. The previous settings that have been entered during the first iteration, for example at steps 105-107, will remain in place for later iterations and no further input of that information is required. However, if the user desires to change those settings an option is provided. In situations where the settings do not need to be changed, the report is e-mailed at step 122. At step 125 the Performance Data report is sent to the desired e-mail service provider and the user may display the report or print the Performance Data report completing the process at step 126. Sample Performance Data reports are depicted at FIG. 8 and FIG. 9. Turning to FIG. 2 the components of the system and the process of transmitting the Performance Data will be described. As discussed above, the smartphone 10 includes a screen 15 to which the appropriate information can be input as discussed above. The input may be via a qwerty key pad that is displayed on the touch screen display 15 or other means such as a mouse or attached keyboard. The smartphone 10 includes telecommunications standard transmission means such as 4G transmission or Wi-Fi transmission via the internet 201. The mobile device transmits via the internet to a Wi-Fi router 220 within a building where the targeted thermostat is located. The Wi-Fi router communicates with a transceiver 215 located within the thermostat 200. The thermostat includes on/off switches 209, its own display 212, a touchpad 213 and a microprocessor 214. The thermostat controls an HVAC system 211 or other heating or cooling system. The microprocessor 214 of the thermostat is programmed to transmit Performance Data regarding the operation of the thermostat 200 on a regular basis, such as every 15 minutes, or more frequently such as every second, or less frequently such as every hour. The transmission of the Performance Data is transmitted via transceiver 215 and Wi-Fi router 220 to the internet 201. For example, a cloud server 201 may collect and organize all of the Performance Data being transmitted from the thermostat 200. The transceiver 215 receives environmental data from sensors 231-236, located in or around a building that houses thermostat 200. Sensors may include outdoor temp sensor 231, indoor temp sensor 233, occupancy sensor 234, smoke sensor 235 and Carbon Monoxide sensor 236. Other sensors may include those for motion detection, barometric pressure, open or closed flu and damper vents and air circulation sensors. In this embodiment, the smartphone 10 and any other device that is linked to the desired e-mail service provider, obtains the Performance Data from the cloud server 201. In an alternate embodiment, the Performance Data may be stored in a memory location within the thermostat or the Wi-Fi router. A request for the data could be processed by the microprocessor 214 by sending the data directly to a requesting mobile device 10 (without use of a cloud server 201). The Performance Data report may include data such as provided in FIG. 8, which provides a thirty day summary of the thermostat, in a particular room, for example, the Main Floor. The report includes date, time, system mode, system state, room temp, set point, fan state, outdoor temp and humidity level headings. An alternate report, as shown in FIG. 9 includes system run time in hours, heat run time in hours, cooling run time in hours, fan run time in hours, average heating temperature by degrees, average cooling temperature by degrees, average outdoor temperature by degrees, average humidity level by percent humidity, highest indoor temperature by degrees, lowest indoor temperature by degrees, highest outdoor temperature by degrees, lowest indoor temperature by degrees, highest humidity level by percent humidity and lowest percent humidity be percent humidity. In an alternate embodiment, a detailed report as shown in FIG. 9 may be provided which lists a time interval of fifteen minutes to provide the following data: date, time, system mode such as cool or heat or a fan, system state, room temperature, setpoint, fan state, outdoor temperature and humidity level. In an alternative embodiment, the interval data may be replaced or supplemented with transition data, where the data would consist of the time when a parameter changed state. As a non-limiting example, the system heating state is recorded in 15-minute intervals and tabulated. The heating system changes state between the 15-minute intervals. The tabulated data may consist of the 15-minute interval data, supplemented with the transitional data of the change between the 15 minute interval. Therefore, it is understood that an application may be loaded onto a mobile computing device such as a smart phone, smart watch, virtual device, PDA or other hardware and software provided on the mobile computing device that allows for quick and easy set-up. The application may link to multiple thermostats in multiple buildings in different locations. So a user may quickly obtain Performance Data about the heating and cooling system in multiple buildings using a single application on a single mobile computing device. Alternate embodiments may provide the report in different formats including excel spreadsheet, charts, dashboard visualization illustrations, or portable document formats. Such alternate reports can provide the entire Performance Data information only segments of the Performance Data or a combination of Performance Data parts combined with other types of data pertaining to a building's environment. The invention could be embodied in other forms without departing from the spirit or essential attributes thereof and accordingly reference should be had to the following claims rather than the foregoing specification as indicating the scope of the invention. |
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039376532 | summary | This invention relates to a diagrid for supporting the core of a nuclear reactor of any type but especially a liquid-sodium cooled fast reactor, the heat generated by the reactor core being recovered in separate heat exchangers which are preferably mounted within the vessel which contains the reactor core and the circulating sodium, the reactor core and heat exchangers being thus incorporated in a so-called integrated structure. The aim of the invention is to endow the coresupport diagrid within the reactor vessel with high mechanical strength, especially with respect to the loads to be carried, while making it possible in particular and especially in the event of accident or of damage to any of its elements to disassemble said diagrid as a single unit, to withdraw the diagrid from the reactor vessel and to replace it by another diagrid of identical design. More precisely, the invention relates to a reactor diagrid of the above-mentioned type constituted by a box structure having end-walls formed by two metallic plates braced by hollow cylindrical support columns which are suitably disposed at intervals within the box structure on a well-defined and uniform pitch. The open ends of said hollow support columns extend through apertures formed in the upper end-wall of the box structure for positioning and supplying liquid sodium to the fuel assemblies which are supported by the diagrid and the arrangement of which in combination forms the reactor core. Finally, the invention is even more specifically concerned with a diagrid of this type comprising a horizontally extending flat upper plate and the axis of the reactor core being vertical, and means whereby the box structure formed by the two braced plates is applied against a support forming part of the vessel which contains the reactor core and the heat exchangers. In accordance with the invention, the diagrid under consideration is characterized in that the lower end plate of the box structure has the shape of a spherical segment or dome which terminates at its periphery in a flat rim and that the upper flat end plate has a circular flange which is parallel to the peripheral rim of the lower plate, said rim and said flange being braced with respect to each other, the flange of the upper end plate being capable of resting on a ring-girder which provides the box structure with a peripheral side restraint and the flat rim of the lower end plate being supported by a flat circular flange formed on a shell element which is rigidly fixed to the reactor vessel. Apart from this main characteristic feature, a reactor diagrid as constructed in accordance with the invention has further accessory features which are preferably to be considered in combination but could be considered separately if necessary and relate in particular to the following points: The flat rim of the lower end plate and the parallel flange of the upper end plate are braced by small vertical stiffening columns. The ring-girder is provided with a top horizontal bearing surface of circular shape having substantially the same radius as the flange of the upper end plate, said flange being applied against said bearing surface by means of coaxial circular grooves, the interengagement of which forms a labyrinth seal against the coolant sodium. Positioning of the flange of the upper end plate with respect to the circular bearing surface of the ring-girder is carried out by means of studs having the shape of sectors which are carried by the flange and engaged in recesses formed in the bearing surface or conversely. The shell element which is rigidly fixed to the reactor vessel has a conical shape and is placed in the line of extension of the lower domical end plate of the box structure. A flexible seal is interposed between a shouldered portion of the flat circular flange of the shell element and the flat rim of the lower end plate of the box structure. The ring-girder is constituted by a hollow metallic torus which is open laterally towards the box structure, said torus being such as to constitute a manifold for supplying the diagrid with the coolant sodium. |
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055315453 | description | DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1 mine roof strata 10 has a vertical borehole 11 which passes through mine roof surface 12. Disposed in the borehole is tubular member 13, the same having a plurality of external threads 14 as indicated. The interior bore 15 of the threaded tubular member has an interior chamfered shoulder area 16 which is conically shaped and which joins an enlarged counter bore area 17. Positioned within bore 15 is a cable length 18 comprised of a king wire 19 and a series of strands 20 helically wound thereabout. Of importance in the invention is the inclusion of one or more cylindrical members 21 and 22 which are pressed end-to-end over the king wire and about which the strands 20 are rewound. More will be said about this later. At this juncture it is important to note that the cable length 18 has an upper end 23 that is anchored by epoxy 23A (see FIG. 6) or otherwise into the upper reaches of borehole 11. The end of extremity 23 may include any one several types of structures, e.g. as common to the art, for aiding in the epoxy securement and anchoring of the cable length within the bore hole. Cable bolt 24 may be thought of as including the cable length 18 and the cylindrical members 21 and 22, while the cable bolt structure 25 may be considered as including cable bolt 24, plus tubular member 13 and torquing nut 26. Torquing nut 26 will include, of course, an interiorly threaded nut body 27 and a forward hemispherical, self-centering head portion 28. This allows for self-centering of the nut and associated structure relative to aperture 29 in the bearing plate or reaction plate 30, positioned about the bore hole and abutting the mine roof surface at 31. In FIG. 3A it is seen that cable length 18 is about to receive cylindrical member 22. The latter may take the form of a hardened roll pin having a surface hardness of the order of not less than that of the strands 20, minus 15%, of the cable length. In FIG. 3A cylindrical member 22 takes the form of a roll pin having a sidewall slot 33 and a long tapered end portion at 32. In FIG. 3B the makeup of the cable bolt comprehends temporarily unwinding the strands 20 so that the cylindrical elements 21 and 22 can be pressed on to the king wire 19. The leading, conically tapered edge 32 of member 22 aids in reducing the likelihood of cable failure. In any event, once the tubular cylindrical members are in place, being installed end-to-end, then the cable strands 20 are rewound so that the cable bolt achieves the structural integrity as seen in FIG. 3C. The greater the pressure bubble effect desired, the greater the over-all length to be selected, whether unitary or segmented, of the the cylindrical element(s) 21, 22. In installation the borehole is first generated and the cable bolt is thrust therein and spun by means of a tool gripping the lower end of cable length 18. An epoxy or other agent 23A (see FIG. 6) is employed for securing the upper end 23 within the upper reaches of the bore hole. The bearing plate 30, having aperture 29 is inserted over cable bolt 24 and externally threaded tubular member 13 freely passes through aperture 29, with torquing nut 26 being threaded thereon. For most installations it will be preferred that tubular member 13 will be pre-installed over the cable bolt 24. The interior counter bore area 17 is preferably dimensioned to receive the cable bolt 24, with the included cylindrical members 21 and 22 in a friction fit, for temporary holding purposes. In any event, and once the upper end of the cable bolt at 23 is securely anchored within the borehole, through upward thrusting and spinning of the cable bolt in a conventional manner, a tool will be employed to tighten nut 26 so as to supply to the cable length a tension preload of perhaps from 1 to 2 tons. In operation, the settling of the mine roof strata 10 above mine roof surface 31 will produce a dilation of such surface a downward direction, thereby causing the bearing plate 30 and also the nut 26 and tubular member 13 assembly likewise to move incrementally downwardly. This causes the enlargement portion 34, see FIG. 3C, as produced by the inclusion of cylindrical members 21 and 22, to advance from the press-fit area within the counterbore of the threaded tubular member upwardly into the primarily bore area. This operation acts to expand radially the metal tubular member 13 proximate the area of members 21 and 22. Such radial expansion is at least primarily within the elastic range of the material of the tubular member so that such action generates, by the tubular member 13, a radial, inward, elastic compression force, serving to enhance the frictional, elastically compressive holding power of the tubular member relative to the cable bolt. Further dilation of the mine roof surface will produce a further riding up, relatively speaking, of the enlargement portion of the cable bolt with respect to tubular member 13. Accordingly the pressure bubble that is produced advances upwardly, relatively speaking, as to cable bolt 24. Again, pressure bubble is defined as the frictional resistance generated through the coaction by and between the cable bolt, with it enlarged portion as previously described, and the elastically expanded material of tubular member 13. Such a friction generating bubble travels upwardly, relatively speaking, in accordance with the downward settling of mine roof strata. At this juncture it is important to note that cylindrical members 21 and 22, preferable comprising roll pins, will generally be case hardened and approach the surface hardness characteristics of tool steel. What is not wanted is any significant plastic deformation of members 21 and 22. Rather, these should preserve the outward integrity of the strands such that the strands 20, such that the latter are useful to urge outwardly the sidewall of the tubular member 13 to produce the elastic compressive forces as previously mentioned. Therefore, the surface hardness of the members should be not less than 15 percent the surface hardness of the strands 20. The structure in FIG. 2 is similar to that seen in FIG. 1 with the exception that this time, in lieu of the inclusions of the cylindrical members 21 and 22 one the king wire, a new cylindrical member 35 is employed which is pressed over the cable length in the manner seen in FIG. 2. Cylindrical member 35 is preferably case hardened and includes a sidewall slot 36 and also a tapered forward leading edge 37. For ease of installation, the cylindrical member 35, gripping the cable length, is lightly frictionally seated within counterbore area 17 such that the forward tapered edge or end 37 engages frusto-conically formed section 16 of the bore area of tubular member 13. Nut 26 is disposed in place as indicated and torqued for desired pre-load. The settling of mine roof strata will produce a downward movement of tubular member 13 relative to the cable bolt so that, relatively speaking, cylindrical member 35 as clamped on the cable travels upwardly into the bore area of tubular member 13. This advance passed the area 16 produces, again, a pressure bubble or elastic expansion of the tubular member 13 at that region which is proximate to cylindrical member 35. Whether the structure in FIG. 1 or FIG. 2 be used, it has been observed that resistant pressures of the order of 28 to 40 tons can be generated, thus producing a controlled settling of mine roof strata through tensioned integrity of the cable bolt installation prior to approaching the ultimate failure point of the cable. FIGS. 4A and 4B amplify upon the assembly of cylindrical member 35 and cable length 18. For fabricating cylindrical member 35, a threaded nipple can be supplied to provide gripping serrations 38. The nipple us turned down to proper, interference-fit size, and wall slot 36 is produced as well as forward tapered portion 38. The unit is then case hardened to a point approaching the characteristics of tool steel, i.e. by heating with a rosebut acetylene torch to 900 degrees F. and then quenching in a bath of oil, and made ready for installation on a selected cable length. The threads 38 serve as serrations to grip against the strands of the cable length, providing a non-slip junction, and which gripping action is enhanced through the pressure bubble effect above recited. For pre-load and adjustment purposes, it is very much desired that a threaded tubular member be used in conjunction with the torquing nut 26 as seen in FIGS. 1 and 2. It is possible, however, for the installation to be used as seen in FIG. 5, wherein tubular member 13A is now secured to bearing plate 30A by welding or otherwise, with the enlargement, see 35, being used with cable length 18 in the manner as previously described. Of course, a nut or other attachment means can be employed to secure the bearing plate 30A with respect to tubular member 13A. FIG. 6 illustrates the generation of the pressure bubble 34A relative to the enlargement 34 of the cable bolt. FIG. 7 illustrates the generation of a similar pressure bubble 34A relative to the cable bolt enlargement as occasioned by the inclusion of member 35, see FIG. 5. Inherent in the invention as shown and described is a method for controlling the dilation of a mine roof, as produced through settling of strata thereabove, comprising the steps of: (1) providing a borehole; PA1 (2) anchoring a cable bolt at its remote end within said bore hole; PA1 (3) providing an elongated, cylindrical enlargement of said cable bolt at its proximate end; PA1 (4) providing an elongated, exteriorly threaded metal tubular member of radially elastic expansion characteristics, said metal tubular member receiving said cable bolt at said cylindrical enlargement in a tube-expansion interference fit; PA1 (5) providing for said tubular member a reaction plate and also a torquing nut, threaded upon said tubular member and backing said reaction plate, PA1 (6) preloading said cable bolt through tightening said torquing nut against said reaction plate, and PA1 (7) creating a controlled, travel resistant pressure bubble as between said cable bolt and said tubular member, whereby to retard in a controlled resistive manner the descent of said tubular member relative to said cable bolt in response to dilation of said mine roof as occasioned through strata settling. While particular embodiments of the present invention have been shown and described it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the essential aspects of the invention and, therefore, the aim in the appended claims is to cover such changes and modifications as fall within the true spirit and scope of the invention. |
054992770 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The focus of the enhancements disclosed in U.S. Pat. Nos. 5,043,135 and 5,339,340 was the annular space in the air riser gap 6 between the outside surface of the containment vessel 7 and the inside surface of the collector cylinder 4, as shown in detail in FIG. 2. Heat is normally transferred to the air stream from these surfaces by convection. In the design of the conventional ALMR, these smooth surfaces have roughness that is characteristic of commercially available, nuclear-grade stainless steels. In accordance with the teaching of U.S. Pat. No. 5,043,135, the surface roughness was increased by creating surface protrusions or boundary layer trips 10 oriented in a direction essentially perpendicular to the air flow direction, e.g., circumferentially around the cylindrical surface of the containment vessel 7. The enhancement of U.S. Pat. No. 5,339,340 involves placing a perforated collector cylinder 11, having multiple openings or holes 12 as indicated in FIG. 2, in the hot air riser 6. The holes 12 can be of arbitrary shape, although a circular shape would be the most economical from a manufacturing standpoint. The degree of perforation, i.e., the total surface of the openings compared to the total perforated collector cylinder surface area, is a variable and can be selected to provide optimum thermal performance. The purpose of the holes 12 is to allow a fraction of the thermal radiative heat flow emanating from the containment vessel 7 to reach and be absorbed by the collector cylinder 4. The remainder of the radiative heat flux is absorbed by the perforated collector cylinder 11. Thus, the surfaces of both the collector cylinder 4 and the perforated collector cylinder 11 receive heat by radiative heat transfer. The fraction that each will receive can be controlled by the degree of perforation selected for the perforated collector cylinder 11. The degree of perforation will be based on an optimization study to achieve maximum overall convective heat transfer from all the heat transfer surfaces in the hot air riser 6. The convective heat transfer rate to the air (the heat sink) depends on the temperature difference between the steel surface and air, and the convective heat transfer coefficient, which in turn depend on the air flow velocities in the individual flow channels created by the perforated collector cylinder 11, namely, inner channel 13 and outer channel 14. The overall optimization process must consider the proper positioning of perforated collector cylinder 11 in relation to the adjacent walls of containment vessel 7 and collector cylinder 4 to achieve the desired air flow distribution between the inner and outer flow channels. The relative positioning of the perforated collector cylinder 11 will also depend on the boundary layer trip configuration if these are included in the heat transfer system. With the air-side RVACS enhancement features of U.S. Pat. Nos. 5,043,135 and 5,339,340 included in the present design, the heat transfer resistance in the inert-gas gap 16 between the reactor vessel 15 and the containment vessel 7 becomes controlling. Since almost all heat transfer in this gap is by thermal radiation, some improvement in the overall heat rejection capability of the RVACS might be achieved by improving the thermal emissivities of the vessel surfaces. However, significant further increase in the thermal emissivities of these surfaces is not possible because they have already been increased by applying carefully prepared oxide layers. Thus, to further improve the passive heat removal capability, other means must be adopted. In accordance with the present invention, enhancement of the passive heat removal capability in an AMLR is achieved by introducing means for removing heat directly from the inert gas in the gap space 16 and inducing significant natural convection flows in the gap space. The increased flow velocities in the gap space 16 result in higher convective heat transfer between the reactor vessel 15 and the containment vessel 7. In addition, RVACS performance is increased in an indirect manner because more draft head and associated RVACS air flow result, as explained hereinafter. Thus, the overall performance of the composite or dual RVACS in accordance with the invention is increased. The degree of increase depends to a large extent on the investment one is willing to make in the inert gas/RVACS air exchanger. The design and operation of the heat removal enhancement means in accordance with the preferred embodiment of the invention is explained with reference to FIGS. 3-6. In accordance with the invention, four inert gas inlet ducts 21 extend horizontally into the outlet plenum and are attached to the wall of the containment vessel 7, as indicated in FIGS. 3 and 4. The inlet ducts 21 are in flow communication with the inert gas-filled gap space 16 (see FIG. 2) via four inlet openings 22 (see FIG. 4). Similarly, four inert gas outlet ducts 23 are also attached to the containment vessel at approximately the same elevation as the inlet ducts 21 and communicate with the inert gas-filled gap space 16 via four outlet openings 24, each of which is positioned at an angular location which is essentially 90.degree. from the corresponding inlet opening 22, as best seen in FIG. 5. Each reactor assembly quadrants has one inlet opening 22 and one outlet opening 24. The design is further modified by including four vertical inert gas riser ducts 25 positioned adjacent to the four RVACS stacks 27 along the entire length of the stack located within the refueling enclosure 28. Each inert gas riser duct 25 is in flow communication at its bottom end with a corresponding one of the four inert gas outlet ducts 23, as shown in FIG. 3, and is covered with thermal insulation 26, as shown in FIG. 4. In addition, each riser duct 25 extends horizontally at the top end thereof through the wall of the associated RVACS stack 27, into the RVACS inlet ducts 29 and joining with one long side of the rectangular RVACS outlet ducts 30, as indicated in FIGS. 3 and 4. Inert gas downcomer ducts 31 are formed by one long side of the RVACS outlet duct 30-which now serves as an inert gas/RVACS air heat exchanger 32; part of the long wall of the RVACS inlet duct 29 adjacent to and opposing the heat exchanger 32; and side walls 33 formed by extending the two short side walls of the RVACS outlet ducts 30 until they join with the opposing wall of the RVACS inlet duct 29, as indicated in FIG. 4. Each downcomer duct 31 extends the entire length of the associated RVACS stack 27. The bottom end of each downcomer duct 31 joins in flow communication with the associated inert gas inlet duct 21, as indicated in FIG. 3. The preferred embodiment of the inert gas/RVACS air heat exchanger 32 described herein is but one of a large number of possible designs that could be considered and which would be acceptable from a structural point of view. However, the disclosed preferred embodiment is considered to be the best mode because it minimizes the modification needed to incorporate the inert gas/RVACS air heat exchanger of the present invention in a conventional plant. In accordance with the invention, modifications are made to the conventional reactor assembly design as indicated in FIGS. 5 and 6. Four flow baffles 34 are placed in the inert gas-filled gap space 16 at 90.degree. intervals along the circumference. These baffles extend from near the top of the reactor vessel 15 and the containment vessel 7 to near the bottom of the cylindrical portions of the vessels. Thus, these flow baffles define four quadrants, two of which are denoted as downflow zones 35 and two of which are denoted as upflow zones 36. The downflow zones 35 are located at circumferential positions corresponding to the inlet openings 22 and the upflow zones 36 are located at circumferential positions corresponding to the outlet openings 24. Note in FIG. 5 that the downflow zones 35 are positioned radially outside of the two sets of electromagnetic pumps 37 whereas the upflow zones 36 are positioned radially outside of the intermediate heat exchangers 38. [Pumps 37 and heat exchangers 38 are conventional components disclosed, for example, in U.S. Pat. No. 4,882,514 to Brynsvold et al.]The reason for this orientation is that the regions of the reactor vessel 15 outside of the intermediate heat exchangers 38 are normally hotter than the regions outside the electromagnetic pumps 37, which will tend to promote flow patterns of the inert gas around the bottom of each baffle as shown in FIG. 6. During operation of the heat removal enhancement means of the present invention, the inert gas in the two upflow zones 36 will rise because vessel surface temperatures are higher in these zones. The inert gas then proceeds through the four outlet openings 24 into the four inert gas outlet ducts 23 and thereafter into the four inert gas riser ducts 25. Each inert gas riser duct is positioned adjacent to a corresponding one of four RVACS stacks 27, as indicated in FIGS. 3 and 5. From there the hot inert gas is ducted into the four inert gas downcomer ducts 31, where the inert gas is cooled by the inert gas/RVACS air heat exchangers 32. The cooled inert gas then flows in sequence through the four inert gas inlet ducts 21, the two downflow zones 35 and then the four inlet openings 22. The cooled inert gas is heated as it is directed downward, but the upward buoyancy thus created is overcome by the much larger positive head created in the elevated inert gas/RVACS air heat exchangers 32. The inert gas flows laterally near the bottom of the reactor assembly, as indicated in FIG. 6, in the open space below the end points of the flow baffles 34 and then enters the two upflow zones 36. The inert gas is heated further as it flows upwards in the upflow zones and then repeats the entire inert gas flow path again. Operation of the dual RVACS increases the decay heat removal capability in three different ways. First, heat is removed directly from the reactor vessel outside surface by the circulating inert gas and transferred to the RVACS outlet air 39 in each inert gas/RVACS air heat exchanger 32. This contribution to the improvement in RVACS performance is by far the largest, perhaps being as much as 90% of the total when the heat exchanger surface area (A) is large. Second, heat is transferred to the containment vessel 7 by the vigorous natural convection flow created in the inert gas-filled gap space 16, which heat is in turn transferred to the conventional RVACS air stream. Finally, the RVACS air flow rate and thereby its performance are increased because heat is added to the RVACS outlet air 39 in the inert gas/RVACS air heat exchangers 32, which provides increased natural circulation head and RVACS flow rate, thus increasing air-side heat transfer coefficients as well as surface-to-air temperature differences. In specific preliminary analysis cases considered for the dual RVACS concept utilizing the enhancement methods described in U.S. Pat. Nos. 5,043,135 and 5,339,340, using a UA product parameter [UA is the product of the heat exchanger overall heat transfer coefficient U and the heat exchanger surface area A] value of 3320 Btu/hr-.degree.F corresponding to utilizing one long side of the RVACS air outlet duct 30 for the inert gas/RVACS air heat exchanger as shown in FIGS. 3 and 5, the overall performance of the dual RVACS increased by about 13%. The corresponding reactor core power that would be possible without reducing the RVACS temperature margin is about 950 MW.sub.t corresponding to an estimated net reduction in bussbar cost of 4 mills/kWh. Further increases are possible by simply providing more heat exchanger surface area. For the other analysis case considered, where all of the RVACS air outlet duct was used as inert gas/RVACS air heat exchanger area, it was determined that by using the dual RVACS of the present invention, the reactor core power can be increased from 840 to 985 MW.sub.t (i.e., a 17.5% increase), resulting in an estimated bussbar cost reduction of 5 mills/kWh. Such a power increase must be consistent with other design constraints that might exist in the current ALMR. However, if this power increase could be implemented, significant net reduction in the electric power generating cost could be realized. Thus, the basic concept of the invention is that heat is removed directly from the reactor vessel outside surface by circulating inert gas. The heated inert gas then circulates via multiple flow paths through heat exchangers which remove heat from the inert gas. The cooled inert gas then flows by natural circulation back to the annular space between the reactor vessel and the containment vessel. This concept has been illustrated by disclosure of the foregoing preferred embodiment. However, it is understood that this novel concept is subject to change following trade-off and detailed thermal performance evaluations without departing from the spirit and scope of the invention. Also, routine variations and modifications of the disclosed apparatus will be readily apparent to practitioners skilled in the art of passive air cooling systems in ALMRs. For example, the heat exchangers could also be arranged to reject heat directly to atmospheric air which is not a part of the RVACS air cooling stream. All such variations and modifications are intended to be encompassed by the claims set forth hereinafter. |
claims | 1. An imaging apparatus comprising: an image sensing unit adapted for sensing an electromagnetic wave image of a subject; and a controller adapted for generating a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing said image sensing unit, so as to overlap a first period and a second period, wherein the first period is an interval between a timing when the first signal is outputted from said controller and a timing when the electromagnetic wave is outputted from said irradiating unit, and wherein the second period is an interval between a timing when the second signal is outputted from said controller and a timing when the initialization of said image sensing unit has been completed. 2. An apparatus according to claim 1 , wherein said controller controls so that one of the first signal and the second signal starts after the other has started and before it has stopped. claim 1 3. An apparatus according to claim 1 , wherein said image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and the second period is an interval between a timing when the second signal, for initializing said photo-electric conversion device, is outputted from said controller and a timing when the initialization of said photo-electric conversion device has been completed. claim 1 4. An apparatus according to claim 3 , wherein the second period is an interval for a pre-discharge of said photo-electric conversion device. claim 3 5. An apparatus according to claim 1 , wherein said image sensing unit has a grid which absorbs scattered rays from the subject, and said controller generates a third signal for driving said grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from said controller and a timing when the initialization of said grid has been completed. claim 1 6. An apparatus according to claim 5 , wherein the initialization of said grid is that a position and a moving speed of said grid should reach a target. claim 5 7. An apparatus according to claim 1 , wherein said image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and a grid which absorbs scattered rays from the subject, and said controller generates a third signal for driving said grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from said controller and a timing when the initialization of said grid has been completed. claim 1 8. An apparatus according to claim 1 , wherein said controller generates the first signal so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after said controller has received a fourth signal which instructs a start of imaging, the fourth period being the longer one of the first and second period. claim 1 9. An apparatus according to claim 5 , wherein said controller generates the first signal so that an irradiation of the electromagnetic wave starts at timing when a fourth period is elapsed after said controller has received a fourth signal which instructs a start of imaging, the fourth period being the longest one of the first, second and third period. claim 5 10. An imaging system comprising: an irradiating unit adapted for irradiating an electromagnetic wave; an image sensing unit adapted for sensing an electromagnetic wave image of a subject using the electromagnetic wave; and a controller adapted for generating a first signal for permitting said irradiating unit to irradiate the electromagnetic wave and a second signal for initializing said image sensing unit, so as to overlap a first period and a second period, wherein the first period is an interval between a timing when the first signal is outputted from said controller and a timing when the electromagnetic wave is outputted from said irradiating unit, and wherein the second period is an interval between a timing when the second signal is outputted from said controller and a timing when the initialization of said image sensing unit has been completed. 11. A method adapted to an imaging apparatus including an image sensing unit adapted for sensing an electromagnetic wave image of a subject, comprising a step of: controlling a controller to generate a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing the image sensing unit, so as to overlap a first period and a second period, wherein the first period is an interval between a timing when the first signal is outputted from the controller and a timing when the electromagnetic wave is outputted from the irradiating unit, and wherein the second period is an interval between a timing when the second signal is outputted from the controller and a timing when the initialization of the image sensing unit has been completed. 12. A method according to claim 11 , wherein in said controlling step, one of the first signal and the second signal is started after the other has started and before it has stopped. claim 11 13. A method according to claim 11 , wherein the image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and the second period is an interval between a timing when the second signal, for initializing the photo-electric conversion device, is outputted from the controller and a timing when the initialization of the photo-electric conversion device has been completed. claim 11 14. A method according to claim 13 , wherein the second period is an interval for a pre-discharge of the photo-electric conversion device. claim 13 15. A method according to claim 11 , wherein the image sensing unit has a grid which absorbs scattered rays from the subject, and said controlling step includes controlling the controller to generate a third signal for driving the grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from the controller and a timing when an initialization of the grid has been completed. claim 11 16. A method according to claim 15 , wherein the initialization of the grid is that a position and a moving speed of the grid should reach a target. claim 15 17. A method according to claim 11 , wherein the image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and a grid which absorbs scattered rays from the subject, and said controlling step includes controlling the controller to generate a third signal for driving the grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from the controller and a timing when an initialization of said grid has been completed. claim 11 18. A method according to claim 11 , wherein in said controlling step, the first signal is generated so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after the controller has received a fourth signal which instructs a start of imaging, the fourth period being the longer one of the first and second period. claim 11 19. A method according to claim 15 , wherein in said controlling step, the first signal is generated so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after the controller has received a fourth signal which instructs a start of imaging, the fourth period being the longest one of the first, second and third period. claim 15 20. A computer-readable storage medium which stores a program for executing a method adapted to an imaging apparatus including an image sensing unit adapted for sensing an electromagnetic wave image of a subject, the method comprising a step of: controlling a controller to generate a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing the image sensing unit, so as to overlap a first period and a second period, wherein the first period is an interval between a timing when the first signal is outputted from the controller and a timing when the electromagnetic wave is outputted from the irradiating unit, and wherein the second period is an interval between a timing when the second signal is outputted from the controller and a timing when the initialization of the image sensing unit has been completed. 21. An imaging apparatus comprising: an irradiating unit for irradiating an electromagnetic wave: a grid which is arranged in irradiating path of the electromagnetic wave; a grid moving unit for moving said grid in the irradiating path; an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements; a storage device for storing combinations of a first time interval which is a time interval between a timing when an irradiation permission signal is sent to said irradiating unit and a timing when an irradiation starts, a second time interval which is a time interval between a timing when said grid moving unit starts driving of said grid and a timing when said grid reaches a target position and a target speed, and a third time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval, the second time interval and the third time interval corresponds to each of a plurality of image sensing conditions; an image sensing condition instructing device for inputting an image sensing condition; and a controller for controlling said irradiating unit, said grid moving unit and said image sensing unit, wherein, said controller selects a combination of the first time interval, the second time interval and the third time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said irradiating unit starts an irradiation, a timing when said grid reaches the target position and the target speed, and a timing when an initialization driving of said image sensing unit is completed coincide with each other, based an the selected combination. 22. An apparatus according to claim 21 , wherein said controller transmits the irradiation permission signal, a driving start signal of said grid moving unit and a start signal of the initialization driving at a timing for coincidence of a timing when said irradiating unit starts an irradiation, a timing when said grid reaches the target position and the target speed, and a timing when an initialization driving of said image sensing unit is completed. claim 21 23. An apparatus according to claim 21 , further comprising an image sensing instruction unit for inputting an image sensing request signal, wherein said controller controls so that a longest time in the first time interval, the second time interval and the third time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device coincide with a time interval between a timing when the image sensing request signal is inputted and a timing when said irradiating unit starts irradiation. claim 21 24. An apparatus according to claim 21 , wherein said controller controls to stop a moving control of said grid moving unit after an actual irradiation time is elapsed from the timing when said irradiating unit starts an irradiation, and to start reading of a signal from said image sensing unit after a predetermined time elapsed from the timing when the moving control has been stopped. claim 21 25. An apparatus according to claim 21 , further comprising an electromagnetic wave detecting device for detecting an amount of the electromagnetic wave, wherein said controller controls to stop a moving control of said grid moving unit based on an output signal of said electromagnetic wave detecting device. claim 21 26. An imaging apparatus comprising: an irradiating unit for irradiating an electromagnetic wave; an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements; a storage device for storing combinations of a first time interval which is a time interval between a timing when an irradiation permission signal is sent to said irradiating unit and a timing when an irradiation starts, and a second time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval and the second time interval corresponds to each of a plurality of image sensing conditions; an image sensing condition instructing device for inputting an image sensing condition: and a controller for controlling said irradiating unit and said image sensing unit, wherein, said controller selects a combination of the first time interval and the second time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said irradiating unit starts an irradiation and a timing when an initialization driving of said image sensing unit is completed coincide with each other, based on the selected combination. 27. An apparatus according to claim 26 , wherein said controller transmits the irradiation permission signal and a start signal of the initialization driving at a timing for coincidence of a timing when said irradiating unit starts an irradiation and a timing when an initialization driving of said image sensing unit is completed. claim 26 28. An imaging apparatus comprising: a grid which is arranged in irradiating path of the electromagnetic wave; a grid moving unit for moving said grid in the irradiating path; an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements; a storage device for storing combinations of a first time interval which is a time interval between a timing when said grid moving unit starts driving of said grid and a timing when said grid reaches a target position and target speed, and a second time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval and the second time interval corresponds to each of a plurality of image sensing conditions; an image sensing condition instructing device for inputting an image sensing condition; and a controller for controlling said grid moving unit and said image sensing unit, wherein, said controller selects a combination of the first time interval and the second time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said grid reaches the target position and the target speed and a timing when an initialization driving of said image sensing unit is complete coincide with each other, based on the selected combination. 29. An apparatus according to claim 28 , wherein said controller transmits a driving start signal of said grid moving unit and a start signal of the initialization driving at a timing for coincidence of a timing when said grid reaches the target position and the target speed and a timing when an initialization driving of said image sensing unit is completed. claim 28 |
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summary | ||
claims | 1. A radiation-shielding container for storing and transporting a radiopharmaceutical, said container comprising:a cap comprising an elongate cylindrical cap shield formed from a radiation-shielding material and having an open end defining a cap aperture and an opposed closed end, said cap shield including an outer cap shield surface and an inner cap shield surface, said inner cap shield surface defining a cap cavity in fluid communication with said cap aperture;a base comprising an elongate cylindrical base shield formed from a radiation-shielding material and having an open end defining a base aperture and an opposed closed end, said base shield including an outer base shield surface and an inner base shield surface, said inner base shield surface defining a base cavity in fluid communication with said base aperture;a first ferromagnetic plug positioned adjacent to an outer surface of one of said cap shield and said base shield. 2. A radiation-shielding container of claim 1, wherein said first plug is affixed to one of said cap shield and said base shield. 3. A radiation-shielding container of claim 1, wherein at least one of said cap shield and said base shield further comprise an outer liner about the outer surface of their respective shield. 4. A radiation-shielding container of claim 3, wherein said outer liner holds said first plug adjacent to the outer surface of said one of said cap shield and said base shield. 5. A radiation-shielding container of claim 3, wherein said first plug is affixed to said outer liner. 6. A radiation-shielding container of claim 4, wherein said outer liner encapsulates said first plug. 7. A radiation-shielding container of claim 4, wherein said outer liner defines a first plug cavity for receiving said first plug. 8. A radiation-shielding container of claim 1, further comprising a second ferromagnetic plug positioned adjacent to the other of said cap and said base as said first plug. 9. A radiation-shielding container of claim 1, wherein said first plug further comprises a substantially planar body having opposed first and second major surfaces. 10. A radiation-shielding container of claim 1, wherein said first plug further comprises a substantially cylindrical body at least partially accommodating at least a portion of said one of said cap shield and said base shield. 11. A radiation-shielding container of claim 1, wherein both said cap and said base further comprise an outer liner about the outer surface of their respective shields, said outer liners providing mating engagement between said cap and said base. 12. A radiation-shielding container of claim 11, wherein said plug is affixed to an outer surface of said liner. |
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abstract | The present invention is directed to a collimator that comprises grooves or channels in the submicrometer to micrometer range. The present invention is also related to uses of a collimator and collimator holder as described herein as well as apparatuses comprising the same. |
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summary | ||
047449420 | description | DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to a presently preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings and described in greater detail in the aforementioned Ser. No. 719,107, the contents of which are hereby incorporated by reference. In the following description, it is to be understood that terms such as "forward", "rearward", "left", "right", "downwardly", and the like are words of convenience and are not to be construed as limiting terms. Referring now to the drawings and particularly to FIG. 1, there is shown a conventional fuel assembly constructed in accordance with well known practices and generally indicated by the reference numeral 10. The fuel assembly 10 basically comprises a well known lower end structure or bottom nozzle 12 for supporting the assembly in the core region of a reactor (not shown). A number of axially extending control guide tubes or thimbles 14 project upwardly from the bottom of nozzle 12. A plurality of spacer grids 16 (only four of which are shown) for transversely spacing and supporting an organized array of elongated fuel rods 18 are axially spaced along guide thimbles 14. The spacer grids 16 are divided into three superadjacent categories, as folloas: lower grid 16L, one or more intermediate grids 16I, and upper grid 16U. As shall be hereinafter described, the grids 16, although generally identical in construction, have differences which produce the resultant benefits of the present invention. Preferably, an instrumentation tube 20 is located in the center of the assembly and an upper end structure or top nozzle 22 is attached to the upper ends of the guide thimbles 14 in a conventional manner to form an integral assembly capable of being conventionally handled without damaging the assembly components. The bottom nozzle 12 and the top nozzle 22 are conventional, including means (not shown) for directing the upward longitudinal flow of a liquid coolant, such as water, to pass up and along the various fuel rods 18 to receive the thermal energy therefrom. Disposed within an opening defined by the sidewalls of the top nozzle 22 is a conventional rod cluster control assembly 28 having radially extending flukes 30 connected to the upper end of control rods 32 for vertically moving the control rods in the control rod guide thimbles 14 in a well-known manner. To form the fuel assembly 10, spacer grids 16 are conventionally attached to the longitudinally extending guide thimbles 14 at predetermined axially spaced locations. The fuel rods 18 are inserted into and through standard cells formed by the interlocking grid straps. The lower nozzle 12 is suitably attached to the lower ends of the guide thimbles 14 and the top nozzle 22 is attached to the upper ends of the guide thimbles 14. For a further description of the fuel assembly 10, reference should be made to U.S. Pat. Nos. 4,061,536 and 3,379,619, the contents of which are hereby incorporated by reference. The fuel assembly 10 depicted in the drawings is of the type having a square array of fuel rods 18 with the control rod guide thimbles 14 being strategically arranged within the fuel rod array. Further, the bottom nozzle 12, the top nozzle 22, and likewise the spacer grid 16 are generally square in cross-section. In that the specific fuel assembly presented in the drawings is for illustrational purposes only, it is to be understood that neither the shape of the nozzles or the grids nor the number and configuration of the fuel rods and guide thimbles are to be limiting, and the invention is equally applicable to shapes, configurations and arrangements other than the ones specifically illustrated. Before describing the spacer grid structure 16 of the present invention in detail, it is noted that the fuel rods 18 are laterally positioned in a predetermined array by the support of spacer grids 16. Spacer grids per se are well known in the art and are used to precisely maintain spacing between fuel rods, to prevent rod vibration, to provide lateral support and, to some extent, to frictionally retain the rods against longitudinal movement. Conventional spacer grids, such as the ones shown and described in U.S. Pat. Nos. 4,061,536 and 3,379,619, referenced above. Turning now to FIG. 2, there is depicted a partially broken away, perspective view of a spacer grid 16 which includes a plurality of interfitted grid straps 24 which are arranged in an egg-crate fashion to create standard cells 34 for separately enclosing the fuel rods 18 (not shown in FIG. 2 for the sake of clarity, but shown in FIG. 1). The spacer grid 16 may also have outer straps 36 interconnected to form a generally square-shaped array which surrounds the grid straps 24 about their heightwise edges 38. For some known fuel assemblies which will be used in a boiling water reactor, it is advantageous for each outer strap 36 to have a central portion 40 and top and bottom resilient border portions 42 and 44, respectively. Preferably, the border portions 42 and 44 are integral with the central portion 40. In any event, the heightwise edges 38 of the grid straps 24 are generally fastened to the surrounding outer straps 36 by an appropriate method, for example, welding. The border portions 42 and 44 may vertically extend beyond the central portions 40 of the outer strap 36. The border portions 42 and 44 may alternatively be fashioned to include mixing vane structures 50 to create turbulence and mixing of the coolant flow through the fuel assembly. In the spacer grid 16, each standard cell 34 has a longitudinal axis (designated by the center line labeled A) and each of its associated grid straps 24 has at least one, and preferably two longitudinally spaced, relatively rigid dimples 46 projecting into the cell 34 on a wall opposing a grid spring 48 for supporting an associated fuel rod 18 therein. Further, it is preferred that each cell 34 have two grid springs, deposed on adjacent walls. Thus, in the preferred embodiment, each fuel rod is supported in each cell at six points. The dimples 46 on a pair of adjacent associated grid straps are preferably generally open to longitudinal coolant flow therethrough, i.e., they face the coolant flow edgewise, while the grid springs 48 on the other adjacent cell walls are generally closed to fluid flow, i.e., their edges are arranged longitudinally with respect to the direction of coolant flow. As will be understood by the artisan, the orientation of th dimples 46 and grid springs 48 can, of course, be reversed. Alternatively, both the springs 48 and dimples 46 can be formed open with respect to coolant flow or both can be formed closed with respect to coolant flow. It is desirable that the dimples 46 and grid springs 48 project generally perpendicularly towards the longitudinal axis of the cell 34. It is also preferred that where a pair of dimples 46 are formed in the same wall of a cell 34, those dimples 46 be axially spaced and aligned. Preferably, as shown in FIG. 2 and in further detail in Ser. No. 719,107, the dimples 46 are generally longitudinally running arches and are generally trapezoidal in shape, while the grid springs 48 are generally transversely running arches having a raised portion for cradling a fuel rod 18 and are likewise generally trapezoidal in shape. It is preferred that the dimples 46 and grid springs 48 be integral with the grid straps 24. Depending upon the location for a particular grid 16, the material used to fabricate the same is selected in accordance with the most predominant functional concerns at each location. For example, in an intermediate portion of the fuel bundle 10, it is important that the neutron absorption cross-section of the grid material be as low as possible in order to avoid parasitic effects. Accordingly, Zircaloy materials are preferred for the intermediate grids 16I, even though such materials do not exhibit long-term resistance to radiation-induced spring relaxation. Because there is considerable turbulence and cross-flow in the lower portion of the fuel bundle 10, the lowermost grid 16L is formed of a material which has less susceptibility to radiation-induced spring relaxation. Accordingly, even though Inconel has a relatively high neutron absorption cross-section, it is useful to manufacture the lower grid 16L from this material because it is capable of maintaining a relatively high spring force on the rods 18 over the useful life of the fuel bundle 10. The neutron cross-section penalty is of less concern and accordingly is accepted. The upper grid 16U may also be fabricated from Inconel, although for a somewhat different reason. In the upper portion of the fuel bundle 10, the grid 16U is located at the upper portion of fuel rods 18 in the gas plenum area. Radiation is relatively light in this area, and the parasitic effect of the high neutron cross-section of the upper grid 16U is negligible. When a fuel rod 18 is located in a cell 34 of a newly formed grid 16, the grid springs 48 and dimples 46 combine to produce an interference fit with the exterior of the rod 18 passing through each cell 34. The lateral spring force secures the fuel rod 18 laterally within the cell 34. The interference fit of the fuel rod in the cell produces sufficient friction with the springs 48 and dimples 46 so that axial movement of the rods is constrained by compressive, axially acting frictional forces. Also, because the springs 48 and dimples 46 are axially offset in a distance d relative to each other and act in opposition (FIG. 2), there is created a bending moment (arrow B) which tends to deflect the rod 18. For example, the grid springs each exert a grid spring force F.sub.s perpendicular to the direction of the cell axis A (FIG. 2). The dimples 46 produce a dimple force F.sub.d in opposition to the spring force but at respective locations above and below the spring force F.sub.s. Thus, a bending moment B is induced in the rod equal to the various forces times the separation d therebetween. The bending moment B tends to deflect the rod, but this tendency alone does not result in severe bowing except when combined with axial compression of the rod coupled with radiation-induced relaxation of the grid springs 48 and dimples 46 in the intermediate grids 16I, whereby the lateral support is diminished. It is known that a fuel rod 18 tends to grow axially as the fuel becomes spent. Such growth, if restrained, aggravates bowing of the rod 18. In FIG. 3A, the resulting forces on a typical prior art arrangement are shown. The symbols F.sub.L, F.sub.I, and F.sub.U represent the respective resulting lower, intermediate and upper forces of the springs and dimples acting upon the rod 18 at the respective lower, intermediate and upper grids. When a conventional fuel bundle 10 is initially fabricated, the forces at each of the grid locations are generally uniform. However, as the fuel rod ages and as the various grids 16 are subjected to high radiation, the spring and dimple forces permanently change. (Changes resulting from high temperature may be ignored for purposes of this explanation, although compensation therefor may be made.) In FIG. 3A, after a selected time period (e.g., one year), the spring forces of the intermediate grid 16I are diminished so that the lower and upper spring forces F.sub.L and F.sub.U are respectively much greater than the intermediate force F.sub.I. Accordingly, the frictional forces on the rod 18 at the upper and lower locations 16U and 16L are greater than in the intermediate positions 16I, so that an effective compressive force F.sub.C acts axially on the rod 18 and amplifies the bending moment B, causing the rod to bow or bend laterally against the diminished lateral spring force of the intermediate grids 16I as shown by reference numeral 18'. The bow or deflection D may be sufficient to cause the rod 18 to touch an adjacent fuel rod. In FIG. 3B, a similar arrangement is shown. However, in accordance with the present invention, the spring and dimple forces are adjusted so that the as-fabricated lower force F.sub.L is greater than the intermediate force F.sub.I, which in turn is preferably greater than the force F.sub.U at the top of the rod 18. After a selected time interval (e.g., one year), the forces acting on the fuel rod 18 change. But because the upper force F.sub.U is less than the lower force F.sub.L to to begin with, little (if any) compressive force is produced on the rod 18 as a result of aging growth. Accordingly, any bending moment resulting from the offset nature of the springs 48 and dimples 46 is unenhanced. Further, even though intermediate spring force F.sub.I on the rod 18 may significantly decrease due to radiation-induced relaxation, the overall forces on the rod 18 are such that strong intermediate lateral support is not critical, because the tendency of the rod 18 to bow is reduced, as compared with the prior arrangement of FIG. 3A. In accordance with the present invention, Table I below shows the various ranges and preferred values of spring forces for the respective grids as fabricated, as well as the values after one year. TABLE I ______________________________________ As Fabricated Sping As Fabricated Preferred After One Grid Force Range/kg. Values/kg. Year/kg. ______________________________________ 16U F.sub.U .5-2 1.5 1.4 16I F.sub.I 1.5-6 5.0 0.5 16L F.sub.L 2-6 3.5 2.5 ______________________________________ Table II below shows the values of a typical prior art arrangement in which the spring force in each of the grid elements is listed as fabricated and after one year: TABLE II ______________________________________ Spring As Fabricated After One Force Values/kg. Year/kg. ______________________________________ F.sub.U 3.5 3.4 F.sub.I 3.5 0.35 F.sub.L 3.5 2.5 ______________________________________ In the prior art, all the as fabricated spring forces are about the same, e.g., 3.5 kg. However, after one year, the upper spring force is greater than the lower spring force and much greater than the intermediate spring force, which differences result in bowing. In the present invention, different spring forces may be designed into the respective grids. As the fuel bundle ages the Zircaloy components will tend to relax, whereby the lateral support for the fuel rods will be diminished. However, because the upper grid 16U initially has a relatively small spring force acting upon the rod 18, the rod will be allowed to grow axially and thereby avoid the compressive forces which enhance the bending moment and tend to bow the rod, especially in view of the diminished lateral support in the intermediate grids 16I. The bending moment induced in the rod 18 is also somewhat lower than the design of the present invention. However, were the bending to remain the same, there would be little or no deflection of the rod, because the compressive force has been virtually eliminated. Clearly, the absolute value of the upper spring force F.sub.U in the prior art starts out relatively high and results in a high compressive force. In the present invention, the upper force is relatively low, thus the resulting compressive force is negligible. While there has been described what at present is considered to be the preferred embodiment of the invention, it would be obvious to those skilled in the art that various changes and modifications could be made therein without departing from the invention. It is intended in the appended claims to cover all such changes and modifications as lie within the spirit and scope of the invention. |
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