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	description	The present invention was first described in U.S. Provisional Patent Application No. 61/191,221 filed on Sep. 8, 2008, the entire disclosures of which are incorporated herein by reference. The present invention relates generally to protective outerwear, and in particular, to a jacket with enhanced protective material construction and safety parachute ejection capabilities intended for use in reducing injuries associated with the operation of personal recreation vehicles such as motorcycles, ATVs, and jet skis. Personal recreational vehicles such as motorcycles, ATVs, and jet skis are an increasingly popular way to spend recreational time. The use of protective gear is one of the most important aspects of personal vehicle operation. The use of such gear when riding motorcycles, for example, greatly helps to reduce the risk of serious injury or death. While the use of protective headgear such as helmets is widespread, there is a paucity of effective gear for the protection of a rider's body and torso area. Many accidents involve physical contact of the upper body area, whether from collision with standing objects or the skidding resultant from being thrown off of a vehicle such as a motorcycle or ATV. Also, many accidents involving motor vehicles are a result of unavoidable collisions when the rider either encounters an unexpected obstacle or loses control of the vehicle in some manner. Accordingly, there exists a need for a means by which suitable anti-impact protection can be provided for the torso area of riders of motorized land or water based recreational vehicles on a personal basis, and a need for a means by which impending collisions can be avoided. Various attempts have been made to provide an apparatus for protection of the body of a motor vehicle operator. Examples of these attempts can be seen by reference to several U.S. patents. U.S. Pat. No. 3,550,159, issued in the name of Alarco, describes an impact-absorbent cellular structure intended for use as protective wear for protecting people from being forcibly thrown against other persons or objects. The Alarco apparatus utilizes air pockets to absorb the brunt of initial impact of the wearer with an external person or object. U.S. Pat. No. 4,694,505, issued in the name of Flosi et al., describes an apparatus utilized as an upper body protector for off-road riders. The Flosi apparatus provides rigid partitions in the manner of an exoskeleton to provide the user with upper body protection, augmented by padded lining and straps for connecting and securing the protective components of the apparatus. U.S. Pat. No. 5,593,111, issued in the name of Jackson et al., describes a system for removing a rider from a vehicle in the event of a crash or expulsion by means of a drag reducing device. The Jackson apparatus comprises a harness system with integral transmitter and receiver system which initiates deployment. Additionally, ornamental designs for a protective jacket exist, particularly U.S. Pat. Nos. D 296,030 and D 426,050. However, none of these designs are similar to the present invention. While these devices fulfill their respective, particular objectives, each of these references suffer from one or more of the aforementioned disadvantages. Many such apparatuses are not ergonomic in a manner that permits fully unimpeded movement to the user. Also, many such apparatuses fail to protect the full extent of the user's upper body in the event of impact. Furthermore, many such apparatuses do not provide a satisfactory means by which a rider can avoid impending collisions and adequately protect themselves during expulsion from a moving vehicle. Accordingly, there exists a need for protective upper body outerwear without the disadvantages as described above. The development of the present invention substantially departs from the conventional solutions and in doing so fulfills this need. In view of the foregoing references, the inventor recognized the aforementioned inherent problems and observed that there is a need for a means to protect the upper body area of a rider during collisions and expulsion from a personal recreational vehicle. Thus, the object of the present invention is to solve the aforementioned disadvantages and provide for this need. To achieve the above objectives, it is an object of the present invention to provide an emergency safety jacket comprising a rear-mounted deployable parachute, an ignition activated propellant device, and a release lever. The jacket is to comprise a padded long-sleeve jacket design with an outer flame retardant shell to help protect the rider from fire, abrasion, and impacts. Another object of the present invention is to further comprise the emergency safety jacket of a jacket shell, a pair sleeves, a sleeve attachment means, a front zipper, a plurality of buckle closures, a release module, and a plurality of abrasion inserts. The jacket shell is intended as a heavily padded sport garment with additional protection provided via the sewn-in abrasion inserts, which are located to help protect from impact at the elbows, shoulders, and the like. Yet still another object of the present invention is to provide closure buckles for the jacket shell, comprising horizontally activated latching devices equally spaced along the zipper. These buckles are intended to provide maximum closure strength in order to withstand tensile forces resulting from the deployment of the parachute. Yet still another object of the present invention is to provide a release module for the parachute, comprising a rectangular electro-mechanical device mounted onto the chest area of the jacket shell. This module is intended to provide an interface by which the rider can quickly and easily deploy the parachute. Yet still another object of the present invention is to provide a parachute assembly, comprising a parachute pouch, a plurality of rupture seams, and a parachute. This assembly is intended to provide a means of quick deployment for a small parachute with a hemispherical canopy which is supported by a plurality of suspension lines. Yet still another object of the present invention is to further comprise the parachute assembly of a mounting plate, plate fasteners, propellant canister fasteners, and a propellant canister. This allows the parachute assembly to be rapidly deployed via a miniature ignition and repellant system similar to those used in automotive air bags. Yet still another object of the present invention is to provide a propellant canister, comprising an integral igniter module, canister fasteners, and propellant. The igniter module is intended to provide an internal ignition source and a primary charge to ignite the solid fuel propellant, causing the parachute to be deployed rearward. Yet still another object of the present invention is to provide an interface portion of the release module for the parachute, further comprising of a manual release lever, an electrical switch, a battery compartment, and internal wiring, allowing the user to grasp and pull the release lever in order to induce electric current into the propellant canister and deploy the parachute. Yet still another object of the present invention is to provide a method of utilizing the device which provides a unique means of protecting a rider of a personal recreational vehicle from various hazards such as expulsion, skidding, fire, and impact in a manner which is simple, quick, and effective. Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description. DESCRIPTIVE KEY 10emergency safety jacket 20jacket shell 22sleeve 24sleeve attachment means 25afront zipper 25b zipper puller 26buckle closure 30parachute assembly 32parachute pouch 35rupture seam 37parachute 38canopy 39suspension line 40release module 42release lever 43switch 44battery compartment 45hinge 46wiring 47battery 50abrasion insert 66mounting plate 68mounting plate fastener 72igniter module 73propellant canister fastener 74propellant canister 75propellant100operator110 vehicle115propelling motion120fastener The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within FIGS. 1 through 6. However, the invention is not limited to the described embodiment, and a person skilled in the art will appreciate that many other embodiments of the invention are possible without deviating from the basic concept of the invention, and that any such work around will also fall under scope of this invention. It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The present invention describes an apparatus and method for an emergency safety jacket (herein described as the “apparatus”) 10, comprising a rear-mounted deployable parachute 37 which provides protection thereto an operator 100 against possible fatal impact when riding a top-accessible vehicle 110 such as a motorcycle, scooter, all-terrain vehicle, or the like. The parachute 37 is deployed using an ignition-activated propellant device 74. In an event of an emergency, the operator 100 grasps and pulls a release lever 42 which in turn deploys the back-mounted parachute 37 causing the operator 100 to be pulled off of a rear portion of the motorcycle 110. Once propelled rearward, the parachute 37 catches air in a similar manner as a drag racing car, thereby ejecting the operator 100 in a rearward motion 115 therefrom the motorcycle 110. The apparatus 10 comprises a padded long-sleeve jacket design 20 with an outer flame retardant shell protecting the operator 100 therefrom fire, abrasion, and impact with stationary objects. Referring now to FIG. 1, a front view of the apparatus 10, according to the preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a jacket shell 20, a pair of sleeves 22, a sleeve attachment means 24, a front zipper 25a, a plurality of buckle closures 26, a release module 40, and a plurality of abrasion inserts 50. The jacket shell 20 comprises a heavily padded sport garment further comprising protective features and materials which provide protection therefrom abrasion, impact, and fire thereto an operator 100 during use. The jacket shell 20 is envisioned being made using a laminated assembly of rugged textile materials such as, but not limited to: NOMEX™ fabric, basalt fabric, fiberglass cloth, glass wool, various foils, stone wool, inner and/or outer leather layers, and the like. Additional protection is provided via sewn-in abrasion inserts 50 along external or internal laminated surfaces of the jacket shell 20. The abrasion inserts 50 are envisioned being made using materials such as, but not limited to: aluminum, hard plastic, fiberglass, or the like, being located thereat anticipated impact areas such as elbows, shoulders, and the like. The sleeves 22 comprise removably attached arm covering members extending thereto a wrist area and being affixed thereto the jacket shell 20 along shoulder and armpit areas using a sleeve attachment means 24 such as a heavy-duty zipper, hook-and-loop fasteners, a plurality of snaps, or the like. The front zipper 25a and closure buckles 26 provide a weather-proof and secure front closure means thereto the jacket shell 20. The front zipper 25a is envisioned to be a common heavy-duty type device with a zipper puller 25b being vertically centered thereupon a front surface of the jacket shell 20 in an expected manner. The closure buckles 26 comprise horizontally activated latching devices being equally-spaced and spanning the front zipper 25a region. The closure buckles 26 provide maximum closure strength thereto a front portion of the jacket shell 20 being capable of withstanding anticipated tensile forces thereto said jacket shell 20 resulting therefrom deployment of the parachute 37. The closure buckles 26 comprises heavy-duty latching components and are envisioned to be similar thereto devices used to latch ski boots, luggage, and the like. The release module 40 comprises a rectangular electro-mechanical device mounted thereto a chest area of the jacket shell 20 using attachment means such as sewing, adhesives, fasteners, or the like. The release module 40 provides an electro-mechanical human interface means required to initiate a timely deployment of the parachute portion 37 when needed (see FIG. 5). Referring now to FIG. 2, a rear view of the apparatus 10, according to the preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a parachute assembly 30 further comprising a parachute pouch 32, a plurality of rupture seams 35, and a parachute 37. The parachute assembly 30 provides quick deployment of a small parachute 37 with a hemispherical-shaped canopy 38 supported by a plurality of suspension lines 39 being enclosed therewithin which is envisioned to be similar to those used in the sport of base-jumping. The parachute assembly 30 is rapidly deployed via a miniature ignition/repellant system similar thereto larger units used in automotive air bag devices (see FIG. 4). During deployment, the parachute pouch 32 is pressurized causing instantaneous failure of a plurality of rear-facing rupture seams 35 along a rear surface of said pouch 32 allowing the parachute 37 to be propelled in a rearward direction (see FIG. 3). The rupture seams 35 comprise weakened intersecting linear regions envisioned to utilize a reduced thickness and are arranged therein an “H”-pattern. Referring now to FIG. 3, an environmental view of the apparatus 10 depicting a deployed state, according to a preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a parachute 37 which when propelled rearward, captures a flow of air, thereby deploying said parachute 37 and causing the operator 100 to be ejected therefrom the moving vehicle 110 in a horizontal rearward direction 115, thereby causing rapid deceleration of the operator's 100 forward velocity before making contact therewith a ground surface. The canopy portion 38 of the parachute 37 is envisioned to be made using similar materials and construction as common hemispherical parachute units used for drag racing cars and skydiving use. The parachute 37 is envisioned being approximately six (6) to ten (10) feet in diameter being capable of producing a desired air-resistance force so as to sufficiently decelerate an adult operator 100, thereby minimizing abrasion injuries and a likelihood of impact therewith stationary objects by said operator 100. Referring now to FIG. 4, a section view of a parachute assembly portion 30 of the emergency safety jacket 10 taken along section line A-A (see FIG. 2), according to a preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a parachute assembly 30 further comprising a mounting plate 66, a plurality of mounting plate fasteners 68, a plurality of propellant canister fasteners 73, and a propellant canister 74. The parachute assembly 30 is rapidly deployed via a miniature ignition/repellant system similar thereto larger units used in automotive air bag devices. During deployment, an electrical current is received by the propellant canister 74 via internal wiring 46 therefrom a manually activated switch 43 (see FIG. 5). The propellant canister 74 further comprises an integral igniter module 72, a plurality of propellant canister fasteners 73, and a volume of propellant 75. The igniter module 72 comprises an internal ignition source and a primary charge in a conventional manner to ignite the solid fuel propellant 75 therewithin the propellant canister 74 which in turn produces rapidly expanding nitrogen gas causing the parachute 37 to be propelled in a rearward direction. The propellant canister fasteners 73 secure said propellant canister 74 thereto the mounting plate 66 being capable of withstanding tensile forces applied during deployment of the parachute 37. The propellant canister 74 provides an attachment means thereto the suspension line portions 39 of the parachute 37 being fastened thereto side surfaces of the igniter module portion 72 using a plurality of fasteners 120. The mounting plate 66 is positioned therebetween the propellant canister 74 and a back portion of the operator 100, thereby providing a means to distribute internal forces and protect the operator 100 as the propellant 75 is ignited. Said mounting plate 66 comprises a rugged plate approximately one-quarter (¼) to one-half (½) inch thick made using materials such as aluminum, fiberglass, acrylonitrile butadiene styrene (ABS), or the like. The mounting plate 66 is to be integrally sewn thereinto a rear face of the jacket shell 20 and further affixed thereto using a plurality of mounting plate fasteners 68. The mounting plate fasteners 68 provide a joining means securing the parachute pouch 32, the mounting plate 66, and the jacket shell 20 thereto each other. Referring now to FIG. 5, a close-up view of a release module portion 40 of the emergency safety jacket 10, according to a preferred embodiment of the present invention, is disclosed. The release module 40 comprises a rectangular electro-mechanical device mounted thereto a chest area of the jacket shell 20 preferably using common fasteners 120 such as rivets, screws, or the like. The release module 40 provides an electro-mechanical human interface means required to initiate a timely deployment of the parachute portion 37 when needed (see FIG. 5). The release module 40 comprises a manual release lever 42, an electrical switch 43, a battery compartment 44, and internal wiring 46. In use, an operator 100 grasps and pulls the release lever 42 causing a contact closure therefrom the switch 43 and subsequent conduction of an electric current thereto the parachute propellant canister 74 located thereupon a rear portion of the jacket shell 20 via internal wiring 46 (see FIG. 2). Power thereto the release module 40 is supplied by one (1) or more direct current (DC) batteries 47 therewithin the battery compartment 44 which is integral thereto the release module 40. The release lever 42 is envisioned to comprise a forwardly extending oval-shaped metal handle having a pivoting lower hinge 45 and being easily accessed thereby the operator 100 during an emergency. Referring now to FIG. 6, an electrical block diagram of the emergency safety jacket 10, according to a preferred embodiment of the present invention, is disclosed. The igniter module 72 receives an electrical current upon closure of the manually activated switch 43. Power is provided thereto the simple circuit by one (1) or more disposable or rechargeable batteries 47 therewithin a battery compartment 44 portion of the release module 40. Common copper conductor wiring 46 is utilized to carry the electrical current through the apparatus 10. It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. The preferred embodiment of the present invention can be utilized by the common user in a simple and effortless manner with little or no training. After initial purchase or acquisition of the apparatus 10, it would be installed as indicated in FIGS. 1 and 2. The method of utilizing the apparatus 10 may be achieved by performing the following steps: loading a fresh battery 47, or batteries, thereinto the battery compartment 44; installing the sleeve portions 22 thereupon the jacket shell 20 using the sleeve attachment means 24, if not previously installed; placing the jacket shell 20 thereupon a torso of an operator 100 in a normal manner; securing the jacket shell 20 by closing the front zipper 25a by pulling the zipper puller 25b; latching the buckle closures 26; operating a motorcycle-type vehicle 110 in a normal manner theretoward a destination; grasping and pulling forwardly on the release lever portion 42 which in turn deploys the parachute 37 therefrom the parachute pouch 32 in an event of an emergency which necessitates rear ejection of the operator 100 therefrom the vehicle 110; ejecting the operator 100 therefrom the rear of the vehicle 110 due to rapid deceleration of said operator 100 caused by an air resistance produced by the canopy portion 38 of the parachute 37 wherein the suspension lines 39 are attached thereto the propellant canister 74 at a first end and thereto the canopy 38 at a second end; utilizing the padding and abrasion insert portions 50 of the jacket shell 20 to provide protection thereto the operator 100 upon contact therewith a ground or street surface; and, benefiting from ejection and impact avoidance thereby an operator 100 of a motorcycle-type vehicle 110 as well as providing bodily protection thereto said operator 100 while utilizing the present invention 10. The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention and method of use to the precise forms disclosed. Obviously many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions or substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
	summary
	claims	1. A method for managing stoppage of a submerged pressurized-water nuclear reactor of a module configured to produce electrical power, the module having a plurality of steam generators each being provided with a safety valve and associated with a standby condenser, the method comprising:detecting a primary/secondary leak of primary fluid into secondary fluid of one of the steam generators;automatically stopping the reactor and isolating the steam generator suffering from the primary/secondary leak;bringing the standby condensers online;monitoring a primary pressure of the primary fluid;determining that the primary pressure is below the set pressure of the safety valve of the steam generator, then isolating the standby condenser of the steam generator suffering from the primary/secondary leak by preventing the primary fluid from being supplied to the standby condenser; andcontinuing to passively cool the reactor with remaining steam generators of the plurality of steam generators and condensers. 2. The method for managing stoppage of the submerged pressurized-water nuclear reactor according to claim 1, wherein the detection of the primary/secondary leak is done by detecting one or several of the following phenomena:increased activity due to contamination by the primary fluid into the secondary fluid,increased secondary water inventory, anddecreased primary water inventory. 3. The method for managing stoppage of the submerged pressurized-water nuclear reactor according to claim 1, wherein the isolation of the standby condenser of the steam generator suffering from the primary/secondary leak is obtained by triggering a controlled valve inserted between the standby condenser and the steam generator suffering from the primary/secondary leak. 4. The method for managing stoppage of the submerged pressurized-water nuclear reactor according to claim 3, wherein the controlled valve is associated with a compressed air supply. 5. The method for managing stoppage of the submerged pressurized-water nuclear reactor according to claim 2, wherein the isolation of the standby condenser of the steam generator suffering from the primary/secondary leak is obtained by triggering a controlled valve inserted between the standby condenser and the steam generator suffering from the primary/secondary leak.
	claims	1. A monitoring system for cement manufacturing, the system comprising:(a) a first cement manufacturing machine;(b) at least a first sensor coupled to the first machine operably sensing a movement condition associated with a portion of the first machine;(c) at least a second cement manufacturing machine located remotely from and performing a different manufacturing operation than the first machine;(d) at least a second sensor coupled to the second machine operably sensing a movement condition associated with a portion of the second machine;(e) a central computer operably receiving signals from the first and second sensors while being remotely located from the first and second machines;(f) software instructions used by the central computer to automatically perform substantially real-time calculations based at least in part on signals from the sensors to determine and report operating problems with sensed portions of the machines; and(g) a hand-held and portable electronic data collector operable to receive signals through the central computer from a third sensor coupled to a third remotely located cement manufacturing machine, the hand-held data collector operably interfacing with the central computer to transfer sensor data to an offline database. 2. The system of claim 1, further comprising at least a first switch matrix and a multiplexer connecting at least the first and second sensors to the central computer to provide at least a sixty-four channel data acquisition device with analog-to-digital sensor-to-multiplexer signal conversion, and the monitored sensors exceeding four signals. 3. The system of claim 1, wherein one of the machines includes a rotating cement kiln. 4. The system of claim 1, wherein one of the machines includes a rotating crusher. 5. The system of claim 1, wherein one of the machines includes a fan. 6. The system of claim 1, wherein one of the machines includes a separator. 7. A monitoring system for cement manufacturing, the system comprising:(a) a first cement manufacturing machine;(b) at least a first sensor coupled to the first machine operably sensing a movement condition associated with a portion of the first machine;(c) at least a second cement manufacturing machine located remotely from and performing a different manufacturing operation than the first machine;(d) at least a second sensor coupled to the second machine operably sensing a movement condition associated with a portion of the second machine;(e) a central computer operably receiving signals from the first and second sensors while being remotely located from the first and second machines;(f) software instructions used by the central computer to automatically perform substantially real-time calculations based at least in part on signals from the sensors to determine and report operating problems with sensed portions of the machines;wherein the first sensor operably senses vibration of a bearing assembly in the first machine, and the central computer automatically compares real-time sensed vibrational values to target values and automatically activates an alarm indicator if the compared value difference exceeds an alarm limit. 8. The system of claim 7, further comprising a hand-held and portable electronic data collector operable to receive signals through the central computer from a third sensor coupled to a third remotely located cement manufacturing machine, the hand-held data collector operably interfacing with the central computer to transfer sensor data to a database. 9. The system of claim 7, wherein one of the machines includes a rotating cement kiln. 10. The system of claim 7, wherein one of the machines includes a rotating crusher. 11. The system of claim 7, wherein one of the machines includes a fan. 12. The system of claim 7, wherein one of the machines includes a separator. 13. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan;(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions; and(g) at least a first switch matrix and a multiplexer connecting the sensors to the central processing unit to provide at least a sixty-four channel data acquisition device. 14. The system of claim 13, wherein at least one of the sensors senses a characteristic of a rotating bearing assembly, and the central processing unit automatically compares real-time sensed vibrational values to target values and automatically activates an alarm indicator if the compared value difference exceeds an alarm limit. 15. The system of claim 13, wherein the sensors send at least 1,000 qualitative samples per second to the central processing unit. 16. The system of claim 13, further comprising:a hand-held electronic data collector communicating with the central processing unit to download sensor data; anda control room including a display visually showing a simulated representation of the kiln, crusher, separator and fan. 17. The system of claim 13, wherein at least one of the sensors senses vibration of a bearing assembly in one of the kiln, crusher, separator or fan, and the central processing unit automatically compares real-time sensed vibrational values from the at least one of the sensors to target values and automatically activates a warning signal if the compared value difference exceeds a limit. 18. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan;(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions; and(g) a display visually showing a simulated representation of the kiln, crusher, separator and fan, and an indication feature based on the sensor signals associated therewith. 19. The system of claim 18, further comprising at least a first switch matrix and a multiplexer connecting the sensors to the central processing unit to provide at least a sixty-four channel data acquisition device. 20. The system of claim 18, wherein at least one of the sensors senses vibration of a bearing assembly in one of the kiln, crusher, separator or fan, and the central processing unit automatically compares real-time sensed vibrational values from the at least one of the sensors to target values and automatically activates a warning signal if the compared value difference exceeds a limit. 21. The system of claim 18, further comprising a hand-held electronic data collector communicating with the central processing unit to download sensor data. 22. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan;(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions; and(g) a hand-held electronic data collector operable to communicate with the central processing unit to download sensor data from a remotely located cement manufacturing machine. 23. The system of claim 22, wherein at least one of the sensors senses vibration of a bearing assembly in one of the kiln, crusher, separator or fan, and the central processing unit automatically compares real-time sensed vibrational values from the at least one of the sensors to target values and automatically activates a warning signal if the compared value difference exceeds a limit. 24. The system of claim 22, further comprising:software instructions operating within the central processing unit automatically determining if there is a problem and a severity of the problem in a real-time manner;the software instructions providing historical trends; andthe software instructions providing maintenance notifications for at least the kiln and crusher. 25. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan; and(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions;wherein the sensors include at least three differently oriented vibration sensors located adjacent the kiln. 26. The system of claim 25, further comprising:a hand-held electronic data collector communicating with the central processing unit to download sensor data; anda control room including a display visually showing a simulated representation of the kiln, crusher, separator and fan. 27. The system of claim 25, further comprising:software instructions operating within the central processing unit automatically determining if there is a problem and a severity of the problem in a real-time manner;the software instructions providing historical trends; andthe software instructions providing maintenance notifications for at least the kiln and crusher. 28. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan;(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions; and(g) an evolutionary learning program being used by the central processing unit to automatically adapt its undesirable condition determination through repeated use over time. 29. The system of claim 28, further comprising:a hand-held electronic data collector communicating with the central processing unit to download sensor data; anda control room including a display visually showing a simulated representation of the kiln, crusher, separator and fan. 30. The system of claim 28, wherein at least one of the sensors senses vibration of a bearing assembly in one of the kiln, crusher, separator or fan, and the central processing unit automatically compares real-time sensed vibrational values from the at least one of the sensors to target values and automatically activates a warning signal if the compared value difference exceeds a limit. 31. The system of claim 28, further comprising:software instructions operating within the central processing unit automatically determining if there is a problem and a severity of the problem in a real-time manner;the software instructions providing historical trends; andthe software instructions providing maintenance notifications for at least the kiln and crusher. 32. A monitoring system for cement manufacturing, the system comprising:(a) a kiln;(b) a crusher;(c) a separator;(d) a fan;(e) sensors detecting movement-related characteristics of the kiln, crusher, separator and fan;(f) a central processing unit receiving substantially real-time and continuous signals from the sensors and using the signals to determine if any undesirable conditions are present with regard to the kiln, crusher, separator and fan, and to identify one or more likely causes of the undesirable conditions;wherein the central processing unit uses at least one of the sensor signals to automatically determine if a mechanically unbalanced movement condition exists. 33. The system of claim 32, further comprising:a hand-held electronic data collector communicating with the central processing unit to download sensor data; anda control room including a display visually showing a simulated representation of the kiln, crusher, separator and fan. 34. The system of claim 32, wherein at least one of the sensors senses vibration of a bearing assembly in one of the kiln, crusher, separator or fan, and the central processing unit automatically compares real-time sensed vibrational values from the at least one of the sensors to target values and automatically activates a warning signal if the compared value difference exceeds a limit. 35. The system of claim 32, further comprising:software instructions operating within the central processing unit automatically determining if there is a problem and a severity of the problem in a real-time manner;the software instructions providing historical trends; andthe software instructions providing maintenance notifications for at least the kiln and crusher. 36. A computer program, stored in memory, comprising:a set of instructions receiving substantially real-time vibration sensor data in cement making machinery;a set of instructions comparing the real-time sensor data to target sensor data;a set of instructions automatically determining if an undesirable condition exists in the cement making machinery, and automatically identifying and reporting a potential cause of the undesirable condition based at least in part on the data comparison and determination; anda set of instructions automatically determining if an undesired rotational imbalance is occurring in the cement making machinery. 37. The computer program of claim 36, further comprising:a set of instructions determining a severity of the undesirable condition;a set of instructions displaying historical trends based on the sensed data; anda set of instructions providing maintenance notifications for the cement making machinery. 38. A computer program, stored in memory, comprising:a set of instructions receiving substantially real-time vibration sensor data in cement making machinery;a set of instructions comparing the real-time sensor data to target sensor data;a set of instructions automatically determining if an undesirable condition exists in the cement making machinery, and automatically identifying and reporting a potential cause of the undesirable condition based at least in part on the data comparison and determination; anda set of instructions automatically determining if an undesired bearing condition is occurring in the cement making machinery. 39. The computer program of claim 38, further comprising:a set of instructions determining a severity of the undesirable condition;a set of instructions displaying historical trends based on the sensed data; anda set of instructions providing maintenance notifications for the cement making machinery. 40. A computer program, stored in memory, comprising:a set of instructions receiving substantially real-time vibration sensor data in cement making machinery;a set of instructions comparing the real-time sensor data to target sensor data;a set of instructions automatically determining if an undesirable condition exists in the cement making machinery, and automatically identifying and reporting a potential cause of the undesirable condition based at least in part on the data comparison and determination; anda set of instructions analyzing analog data from at least fifty vibrational sensors associated with multiple cement making machines in a substantially real-time and continuous manner. 41. The computer program of claim 40, further comprising a set of instructions automatically determining if an undesired rotational imbalance is occurring in the cement making machinery. 42. The computer program of claim 40, further comprising:a set of instructions determining a severity of the undesirable condition;a set of instructions displaying historical trends based on the sensed data; anda set of instructions providing maintenance notifications for the cement making machinery. 43. A computer program, stored in memory, comprising:a set of instructions receiving substantially real-time vibration sensor data in cement making machinery;a set of instructions comparing the real-time sensor data to target sensor data;a set of instructions automatically determining if an undesirable condition exists in the cement making machinery, and automatically identifying and reporting a potential cause of the undesirable condition based at least in part on the data comparison and determination; anda set of instructions visually displaying a simulated representation of the cement making machinery and an indication image of the sensor data. 44. The computer program of claim 43, further comprising:a set of instructions determining a severity of the undesirable condition;a set of instructions displaying historical trends based on the sensed data; anda set of instructions providing maintenance notifications for the cement making machinery. 45. A method of using and monitoring machines to manufacture cement, the method comprising:(a) moving a portion of a first machine;(b) detecting a characteristic associated with the movement of step (a);(c) moving a portion of a second machine remotely located relative to the first machine;(d) detecting a characteristic associated with the movement of step (c);(e) moving a portion of a third machine remotely located relative to the first and second machines;(f) detecting a characteristic associated with the movement of step (e);(g) making cement with the machines;(h) substantially simultaneously using remotely located software instructions to automatically determine if an undesirable mechanical condition exists in the first, second and third machines based at least in part on the detected characteristics, and if so, automatically identifying a probable cause; and(i) using an evolutionary learning calculation to assist in making the probable cause identification. 46. The method of claim 45, further comprising using the software instructions to compare historical detected data to real-time detected characteristic data. 47. The method of claim 45, further comprising transmitting sensed data from a central processing unit, associated with a central control room, to a hand-held electronic data collector, the central processing unit running the software instructions. 48. A method of using and monitoring machines to manufacture cement, the method comprising:(a) moving a portion of a first machine;(b) detecting a characteristic associated with the movement of step (a);(c) moving a portion of a second machine remotely located relative to the first machine;(d) detecting a characteristic associated with the movement of step (c);(e) moving a portion of a third machine remotely located relative to the first and second machines;(f) detecting a characteristic associated with the movement of step (e);(g) making cement with the machines;(h) substantially simultaneously using remotely located software instructions to automatically determine if an undesirable mechanical condition exists in the first, second and third machines based at least in part on the detected characteristics, and if so, automatically identifying a probable cause;(i) rotating a hollow tube of a cement kiln machine;(j) energizing a motor to rotate a transmission which rotates the tube;(k) supporting the transmission with a stationary block and a bearing assembly located between the transmission and the block;(l) heating crushed rock in the kiln to make clinker;(m) receiving signals from a first set of sensors located adjacent the block and operably sensing vibrations of at least one of: (a) the tube, (b) the transmission, and (c) the bearing assembly;(n) receiving signals from a second set of sensors located adjacent the motor and operably sensing vibrations of at least one of: (a) the motor and (b) the transmission;(o) using the software instructions to determine if an undesired rotational imbalance is occurring within the kiln machine and if an undesired rotational bearing condition is occurring within the kiln machine; and(p) visually displaying a simulated representation of the kiln machine and a sensor indication image. 49. The method of claim 48, further comprising using an evolutionary learning calculation to assist in making the probable cause identification. 50. The method of claim 48, further comprising transmitting sensed data from a central processing unit, associated with a central control room, to a hand-held electronic data collector, the central processing unit running the software instructions.
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	description	1. Field of the Invention The present invention relates to a technique of estimating the time when a product composed of a plurality of parts fails and the degree of degradation of the parts, and reflecting them in maintenance planning. 2. Description of the Related Art Conventional maintenance planning has depended on the experience and guesswork of servicemen. This has obstructed balancing the risk of user's loss due to the reason that products become unavailable and the cost of maintenance. Specifically speaking, to reduce the risk of product failure, parts with high risk of failure are replaced before the end of the life, so that excessive replacement is carried out, increasing maintenance cost. In contrast, when products are used to the end of life so as to decrease the maintenance cost, servicemen have to make a visit after the products fail, thus increasing downtime to increase user's loss due to the reason that the products are unavailable. Consequently, the risk and the cost are in a trade-off relationship. Some other business sectors adopt maintenance planning based on costs and risks. It is, however, difficult to estimate the costs when replacement parts (consumable parts) increase in number. In other words, at the time of determining if consumable parts should be replaced, it takes extremely high calculation cost to determine the best maintenance planning for the best combinations of consumable parts to be replaced. In addition, since it cannot be determined that how much the next visit time is delayed, the cost cannot be simply calculated. The invention is made to solve the above-described problems. Accordingly, it is an object of the invention to provide a technique of reducing maintenance costs and also product downtime losses. In order to achieve the above object, according to the invention, there is provided a maintenance system that calculates a timing to make a visit for maintenance work of consumable parts of a machine to be maintained. The system includes: a visit-interval calculating section for calculating a visit interval to make a visit for maintenance work for each consumable part on the basis of a failure rate distribution; a replacement-interval calculating section for calculating a replacement interval to replace the consumable parts for each consumable part on the basis of the failure rate distribution; and a visit-timing calculating section for calculating a timing to actually visit the machine to be maintained on the basis of the visit interval calculated by the visit-interval calculating section and the replacement interval calculated by the replacement-interval calculating section. According to the invention, there is provided a maintenance method for calculating a timing to make a visit for maintenance work of consumable parts of a machine to be maintained. The method includes: a failure-rate-distribution calculating step of calculating the failure rate distribution of each consumable part on the basis of maintenance historical data, that is, history information on maintenance work performed for the machine to be maintained; a visit-interval calculating step of calculating a visit interval to make a visit for maintenance work for each consumable part on the basis of the failure rate distribution calculated in the failure-rate-distribution calculating step and the maintenance historical data; a replacement-interval calculating step of calculating a replacement interval to replace the consumable parts for each consumable part on the basis of the failure rate distribution calculating in the failure-rate-distribution calculating step and the maintenance historical data; and a visit-timing calculating step of calculating a timing to actually visit the machine to be maintained on the basis of the visit interval calculated in the visit-interval calculating step and the replacement interval calculated in the replacement-interval calculating step. According to the invention, there is provided a maintenance program for a computer to execute a process of calculating a timing to make a visit for maintenance work for consumable parts of a machine to be maintained. The program includes: a failure-rate-distribution calculating step of calculating the failure rate distribution of each consumable part on the basis of maintenance historical data, that is, history information on maintenance work performed for the machine to be maintained; a visit-interval calculating step of calculating a visit interval to make a visit for maintenance work for each consumable part on the basis of the failure rate distribution calculated in the failure-rate-distribution calculating step and the maintenance historical data; a replacement-interval calculating step of calculating a replacement interval to replace the consumable parts for each consumable part on the basis of the failure rate distribution calculated in the failure-rate-distribution calculating step and the maintenance historical data; and a visit-timing calculating step of calculating a timing to actually visit the machine to be maintained on the basis of the visit interval calculated in the visit-interval calculating step and the replacement interval calculated in the replacement-interval calculating step. An embodiment of the invention will be described hereinbelow with reference to the drawings. FIG. 1 is a schematic diagram of a maintenance system according to an embodiment of the invention. FIG. 1 shows an example in which a serviceman 102 maintains a plurality of multifunctional peripherals (MFPs) installed at a user, with one service center having a maintenance system 103 as the base. In conventional maintenance, the serviceman 102 has visited a user every preventive maintenance (PM) set for each MFP, and performed replacement of consumable parts, and cleaning and checking of the operations of MFPs. The serviceman 102 also has made a visit to repair the MFPs when called from the user in case of accidental failure, in addition to PM. For the PM work, since one MFP includes a plurality of consumable parts, all the consumable parts are not always degraded at the PM. Accordingly, replacing consumable parts that have not yet reached the end of life causes losses. Also, replacing only failed consumable parts at the occurrence of accidental failure causes replacement time gap to the cycle of the PM. Accordingly, the serviceman 102 controls the replacement time for the consumable parts individually on the basis of the experience while taking the set PM cycle as the base to thereby reduce losses. However, cutting down on costs by excessively delaying replacement time to increase the available time of consumable parts increases the risk of the failure of the consumable parts, resulting in the loss on the user due to the reason that the MFP becomes unavailable. Also, varying replacement time from item to item will increase the number of visits, resulting in an increase in maintenance cost. Accordingly, the maintenance system 103 according to the embodiment is configured to calculate the failure rate distribution for each consumable part on the basis of past maintenance historical data and to calculate a next visit time and the list of consumable parts to be replaced at that time from the calculated failure-rate distribution. The maintenance system 103 includes a storage means 104 for storing a maintenance history; a failure-history analyzing means (failure-rate-distribution calculating section) 105 that analyzes the maintenance history stored in the storage means 104 to obtain a failure rate distribution, a count progress distribution, and a visit history, and stores them in the storage means 104; and a maintenance planning means (a visit-interval calculating section, a replacement-interval calculating section, and a visit-timing calculating section) 106 for determining visit time and replacement parts from cost-related constants, the failure rate distribution, the count progress distribution, and the visit history which are stored in the storage means 104. FIG. 2 is a block diagram showing the system configuration of the maintenance system 103. As shown in FIG. 2, the maintenance system 103 includes a CPU 201, a memory 202 connected to the CPU 201 via a bus, an external storage unit 203, an input unit 204, and an output unit 205. The storage means 104 shown in FIG. 1 corresponds to the external storage unit 203, while the failure-history analyzing means 105 and the maintenance planning means 106 are configured for the calculations of the CPU 201. The CPU 201 is responsible for executing various processings of the maintenance system 103, and also for achieving various functions by executing the programs stored in the memory 202. The memory 202 is, e.g., a ROM or a RAM, and is responsible for storing various information and programs used in the maintenance system 103. FIG. 3 shows a format of data for use in the maintenance system 103, in which eight tables are defined. The tables are a user table 301 in which constants associated with a user are set; a support center table 302 in which constants for a support center are set; a machine type table 303 in which constants for a machine type are set; a machine table 304 in which variables calculated from the constants for a machine and the condition of use are set; a consumable part table 305 in which constants for a consumable part and failure-rate variables calculated from market data are set; a user-to-machine table 306 indicative of the correspondence between a user and a machine; a maintenance history table 307 in which the history of maintenance work by a serviceman is recorded; and a consumable-part condition table 308 in which the condition of a consumable part is set. These tables are stored in the storage means 104. The arrows in the figure each indicate that the attribute at the base of the arrow is set to the attribute of the end of the arrow. The character string ahead of “.” in the attribute at the end of the arrow indicates the name of a reference table, while the character string after “.” indicates the name of the attribute of the reference. For example, “machine.ID”in the maintenance history table 307 indicates “ID” in the machine table 304. The serviceman 102 updates the maintenance history table 307 in the storage means 104 from the work sheet describing a maintenance report according to the format of the maintenance history table 307. The maintenance history table 307 is an example of data updated. The failure-history analyzing means 105 estimates the failure rate distribution for each consumable part on the basis of the maintenance history table 307 by substitution to Weibull distribution, which is widely used in failure distribution analysis (a failure-rate-distribution calculating step),F(t)=1−exp(−t/η)m (m is a shape parameter, and η is a scale parameter) Here a photoconductor drum which is a consumable part of a machine type A will be described as an example of the MFP. First, the operation of the failure-history analyzing means 105 will be specifically described. The failure-history analyzing means 105 extracts data on the photoconductor drum from the maintenance history table 307 read from the storage means 104 to obtain the failure rate distribution of the photoconductor drum, and calculates a failure interval. Specifically, the failure-history analyzing means 105 extracts all the tuples in which “machine type.name” is “type A” and “consumable part.abbreviated name” is “photoconductor drum” and all the tuples in which “machine type.name” is “type A” and “consumable part.abbreviated name” is “all PM replaced (indicating that all consumable parts have been replaced) from the maintenance history table 307 described in FIG. 4, and calculates a failure interval from the difference from the count of the preceding replacement. The column “end of life” on the right end of the maintenance history table 307 shown in FIG. 4 is added for the description. Items indicated by “x” are data when the photoconductor drum failed before PM, while items indicated by “o” are data when the photoconductor drum was replaced without failure because it reached PM. Data including the data (items of “o”) of items replaced before failure is referred to as closed data. A known method for analyzing such data includes “a cumulative hazard method”. The failure-history analyzing means 105 estimates a shape parameter m and a scale parameter η of Weibull distribution from the extracted failure intervals of the tuples by the cumulative hazard method, and updates the failure-distribution variables in the consumable part table 305 detailed in FIG. 5. Specifically speaking, the failure-history analyzing means 105 extracts tuples in which “machine type.name” is “type A” and “abbreviated name ” is “photoconductor drum” from the consumable part table 305 shown in FIG. 5, and subtracts the shape parameter m to “failure distribution parameter 1” and the scale parameter η to “failure distribution parameter 2” (K indicates ×103). For “failure distribution group”, a constant “0” corresponding to Weibull distribution is set. The calculation is made for each of the consumable parts to update the consumable part table 305 in the storage means 104. The consumable part table 305 of FIG. 5 is an example of data updated. At the same time, the failure-history analyzing means 105 calculates a copy-number progress distribution per day for each machine with the maintenance history table 307. Specifically, the failure-history analyzing means 105 extracts tuples of the same ID from the maintenance history table 307, and calculates the mean value and the dispersion of the count progress from the difference between visit date (the number of days) and changes in count (the degree of progress) to update the “count progress average” and the “count progress dispersion” in the machine table 304 detailed in FIG. 6. The failure-history analyzing means 105 also updates the latest visit date and the replacement date for the consumable parts for each machine. For the visit date, the latest visit date and the “count” at that time of all the tuples extracted using “machine.ID” from the maintenance history table 307 are set, as the latest count data, to the “visit date” and the “count” in the machine table 304. The machine table 304 in FIG. 6 shows an example of data updated. For the replacement date for the consumable parts, the latest “visit date” in the tuples of the consumable parts, “all PM replaced”, and “setup” in the column of “consumable part.abbreviated name” are extracted from all the tuples extracted for “machine.ID” from the maintenance history table 307, and the latest “visit date” is set in the “count acquisition date” in the consumable-part condition table 308 detailed in FIG. 7. Value “0” is set for the “count” in the consumable-part condition table 308. The consumable-part condition table 308 of FIG. 7 shows an example of data updated. The operation of the maintenance planning means 106 will next be described. The maintenance planning means 106 has “a strategy plotting mode” and “a visit-date presenting mode”. The strategy plotting mode is executed when a fixed amount of maintenance historical data is added or at regular timings such as once per month. The visit-date presenting mode is executed every day. The modes will be specifically described hereinbelow. Strategy Plotting Mode The details of the processing in the strategy plotting mode will be described with reference to the flowchart of FIG. 8. “A visit interval” to make a visit for maintenance work and “a replacement interval” to replace consumable parts are calculated and set for each consumable part of each machine. The serviceman 102 performs maintenance work according to the visit interval and the replacement interval. Specifically, the serviceman 102 makes a visit to a specific machine to be maintained even if one of consumable parts reaches the visit interval, and replaces all consumable parts that have reached the replacement interval. Here the visit interval and the replacement interval do not indicate a simple time interval but are expressed by a count value indicative of the number of sheets processed by MFPs to be maintained. This expression by count values allows maintenance according to the results of actual use of MFPs to be maintained. A method for calculating the “visit interval” and the “replacement interval” will be specifically described. The maintenance planning means 106 simulates the maintenance work for a period set in the “simulation period” of the support center table 302, and calculates a visit interval and a replacement interval in which the costs are minimized. For the method of calculation, for example, random visit interval and replacement interval are set using a heuristic method such as a Monte Carlo method or a generic algorithm, and the simulation of maintenance work is repeated to calculate the costs, of which a visit interval and a replacement interval in which the costs is minimized are adopted. Although the longer the simulation period is the better, the calculation time increases correspondingly. It is therefore desirable that an enough period be set for an average machine failure time. The costs here indicate the sum of labor costs for the serviceman 102, the cost of materials of replaced consumable parts, losses (downtime losses) due to the reason that a user cannot use the machine because of unexpected failure. A specific example of the simulation using the Monte Carlo method will be described. FIG. 9 shows samples in which maintenance strategies (combinations of a visit interval and a replacement interval for each consumable part) for a machine whose “machine.ID” is 100213 are set, in which 2,000 kinds of maintenance strategy samples are produced at random (a visit-interval calculating step and a replacement-interval calculating step). Although the samples are basically produced at random, it is desirable to produce the samples in the vicinity of a visit interval and a replacement interval estimated empirically from the failure rate distribution of each consumable part so as to produce no useless sample. Maintenance work simulation is performed for each of the 2,000 maintenance strategies to obtain a sample with the minimum cost. The maintenance work simulation for the maintenance strategy sample 1 will next be described with reference to FIG. 8. The maintenance planning means 106 compares the “machine.name” of the machine table 304 (not shown in FIG. 5, refer to FIG. 2) and the “machine type.name” of the consumable part table 305 (refer to FIG. 4) for the “machine.ID” 100213 to extract all the tuples in the consumable part table 305. The maintenance planning means 106 then generates random numbers by a known method on the basis of the failure probability indicated by the “failure distribution group”, “failure distribution parameter 1”, and “failure distribution parameter 2” in the consumable part table 305 to calculate the next failure times of the consumable parts (S81). The shortest of the calculated next failure times is set to a next failure time candidate (S82). The maintenance planning means 106 also compares the “ID” in the machine table 304 and the “machine.ID” in the consumable-part condition table 308 to extract all conforming tuples in the consumable-part condition table 308, and calculates the next visit of the serviceman 102. Specifically, the maintenance planning means 106 calculates the “visit interval” set in the sample 1 of FIG. 9 for the extracted consumable-part condition (a visit-interval calculating step) (S83), and sets the shortest as a next visit time candidate (S84). The calculated next-failure-time candidate and next-visit-time candidate are compared, whereby an event is determined. When the next-failure-time candidate is shorter than the next visit-time candidate (Y in S85), the next-failure-time candidate is set to an elapse time as a failure occurrence event (S86). Then consumable parts to be replaced are determined and the costs thereof are calculated. Among all the consumable parts except failed consumable parts, those whose replacement interval is shorter than the next failure time candidate are determined to be consumable parts to be replaced, with reference to the “replacement interval” in the consumable-part condition table 308 calculated in advance (in the replacement-interval calculating step), and the costs thereof are calculated as the sum of the labor costs, the costs of materials, and downtime losses (S87). labor costs=(“user.travel time”+Σ “consumable part.replacement time” of consumable part to be replaced) ×unit price of serviceman material costs=Σ “consumable part.unit price” of consumable part to be replaced downtime losses =“user.travel time”×“machine.downtime loss unit price” The “user.travel time” indicates a travel time from a support center to a user address. When the next failure time candidate is longer than the next visit time candidate (N in S85), the next visit time candidate is set to an elapse time as a premaintenance event (S88). Consumable parts to be replaced are determined and the costs are calculated. Among all the consumable parts except consumable parts to be premaintained (related to the visit interval), those shorter than the next visit time candidate are determined to be consumable parts to be replaced, with reference to the “replacement interval” in the preset consumable-part condition table 308, and the costs are obtained as the sum of the labor costs, material costs, and downtime losses (S89). labor costs=(“user.travel time”+Σ “consumable part.replacement time” of consumable part to be replaced)×unit price of serviceman material costs=Σ “consumable part.unit price” of consumable part to be replaced downtime losses =0 The downtime here is set to 0 on the assumption that the serviceman 102 works while the user is not using the machine under an agreement with the user, and the time until the serviceman 102 runs to the user in case of unexpected failure is assumed to be downtime. At the occurrence of the event, for replaced consumable parts, a next failure time is newly calculated, and for consumable parts that are not replaced, the elapse time is subtracted from each of the next failure time and the visit interval calculated, and the next failure time and the visit interval are updated (S90). In this manner, the determination of the next failure time candidate and the next visit time candidate (S91), the determination of event, the determination of consumable parts to be replaced, and the calculation of costs are repeated until the elapsed time ends during the simulation period (N in S92). One set of the simulation is repeated for all the samples of FIG. 9, from which a sample in which the calculated cost is the minimum is adopted, and “consumable-part condition.visit interval” and “consumable-part condition.replacement interval” are set as the optimum strategy (a visit-timing calculating step). FIG. 10 shows the results of simulation for the samples. In this example, the cost per one count in the 112th sample is the minimum, so that it is adopted as the optimum strategy. Visit-Date Presenting Mode The “visit-date presenting mode” will be described. The “visit-date presenting mode” assumes a case in which the serviceman 102 checks the next visit date. Desirable visit interval and replacement interval are set in advance in the strategy plotting mode. The serviceman 102 checks the visit date by inputting the “machine.ID” of a machine in his charge. The maintenance planning means 106 compares the “ID” in the machine table 304 and the “machine.ID” in the consumable-part condition table 308 to extract all conforming tuples in the consumable-part condition table 308, and refers to “count acquisition date”, “count”, “visit interval”, and “replacement interval”. The maintenance planning means 106 also refers to “count progress average” in the machine table 304. The maintenance planning means 106 then calculates scheduled visit date for each consumable part by the following expression.scheduled visit date=count acquisition date+visit interval/count progress average The shortest of the scheduled visit dates of the consumable parts is determined as a visit date. Next, a scheduled replacement date is calculated for consumable parts except that of the shortest scheduled visit date by the following expression.scheduled replacement date=count acquisition date+replacement interval/count progress average A consumable parts whose scheduled replacement date is shorter than the visit date is determined as a consumable part to be replaced, and is presented together with the visit date. The visit date may be estimated by period using the “count progress distribution” in the machine table 304. Accordingly, in the above-described embodiment, the setting of two references, the visit interval and the replacement interval, for each consumable part enables the serviceman 102 to know “when to make a visit” and “which consumable part to be replaced”. The calculating of a desirable visit interval and replacement interval in advance, and normally calculating the next visit date according to the determined strategy reduces calculation cost. FIG. 11 is a flowchart for the process (maintenance method) of the maintenance system according to the embodiment. The failure-history analyzing means 105 calculates the failure rate distribution for consumable parts on the basis of maintenance historical data, that is, history information on the maintenance work executed for machines to be maintained (the failure-rate-distribution calculating step) (S701). The maintenance planning means 106 calculates “visit interval”, that is, the count of visit interval for maintenance, on the basis of the failure rate distribution calculated in the failure-rate-distribution calculating step and the maintenance historical data (the visit-interval calculating step)(S702). The maintenance planning means 106 calculates “replacement interval”, that is, the count of replacement interval of consumable parts, on the basis of the failure rate distribution calculated in the failure-rate-distribution calculating step and the maintenance historical data (the replacement-interval calculating step)(S703). In the visit-interval calculating step and the replacement-interval calculating step, values close to intervals at which the failure rate is estimated to be higher than a predetermined rate are calculated, on the basis of the failure rate distribution of the consumable parts, which is calculated in the failure-rate-distribution calculating step. The maintenance planning means 106 calculates the timing to actually visit a machine to be maintained on the basis of the “visit interval” calculated in the visit-interval calculating step and the “replacement interval” calculated in the replacement-interval calculating step (the visit-timing calculating step) (S704). The steps of the process (maintenance method) of the maintenance system described above are achieved by the CPU 201 through the execution of a maintenance program stored in the memory 202. The embodiment has been described for the case in which the function of executing the invention is stored in the apparatus in advance. However, it is to be understood that the invention is not limited to that but the same function may be downloaded to the system via a network, or alternatively, the same function stored in a memory medium may be installed to the system. The memory medium may be any type of medium, such as CD-ROMs, that can store programs and can be read by the system. The function acquired in advance by installation or downloading may be achieved in cooperation with the operating system (OS) or the like in the system. While the invention has been described in detail with reference to a specific embodiment, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. The invention can provide a technique of reducing the costs for maintenance and also the downtime of products.
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	description	This application claims benefit of U.S. Provisional Patent Application Ser. No. 61/856,754, filed in the U.S. Patent and Trademark Office on Jul. 21, 2013, which is incorporated herein by reference in its entirety. Trans-radial access (“TRA”) is an increasingly utilized procedure for peripheral interventions on catheter tables. Peripheral interventions via a patient's left wrist are advantageous from an anatomical standpoint. First, due to proximity and catheter support, sub-clavian, vertebral and certain carotid interventions are more easily performed via a patient's arm rather than the groin. Second, renal and mesenteric vessels have a superior oriented origin, and their access from the arm is easier and more natural. Third, lower extremity interventions, particularly iliac and proximal superficial femoral artery, are more accessible from the arm when there is contralateral disease, or if the iliac bifurcation is hostile. For the treatment of iliac disease, there are specific potential advantages for a radial puncture compared with the more traditional femoral approach. Femoral access may be difficult when crossing an iliac lesion from the contralateral side. Moreover, precise stent placement may be problematic if contralateral iliac disease needs to be treated. In such cases, TRA may permit same-day discharge and prevent the need to access the contralateral groin and for crossover. However, traditional TRA platforms do not permit both right and left radial access from either the left or right side of the table. Specifically, existing platforms do not permit left radial access and operation from the right side of the operating table. Additionally, existing arm boards that include radiolucent materials so as to not interfere with medical imaging provide little to no protection from ionizing radiation to, e.g., a doctor performing left radial access procedures from the right side of the catheter table. What is needed in the field of trans-radial access is a left radial access, right room operation system that is also suitable for use during left radial lower extremity procedures. The system should also reduce or eliminate staff exposure to ionizing radiation during catheterization procedures without impairing the ability to obtain the necessary diagnostic medical images during the procedures. The system also should be economical to manufacture, and it should be simple, effective, and reliable to use and reuse. The present disclosure is directed in general to left radial access, right room operation, lower extremity peripheral platforms for use in left radial peripheral interventions. More specifically, the trans-radial access platform provides radiation reduction and allows for left and right radial access, for different procedures, from lower extremity peripheral to pacemaker and cardiac interventions. As will be understood from the present disclosure and by its practice, the various embodiments described herein and their equivalents are simple to manufacture, install and use. For example, in one embodiment according to the present disclosure, a system is provided for use in supporting a patient lying in supine position with left arm secured across the patient's midsagittal or median plane during a lower extremity peripheral procedure. The system may be a left radial access, right room operation, peripheral intervention system for use with an imaging system. The peripheral intervention system may have a left radial base that stabilizes a left arm of a patient across a midsagittal plane of the patient during a lower extremity peripheral intervention on a procedure table. A right radial base may be positioned substantially parallel to an operating surface of the procedure table, the right radial base being transradiant and configured to position a right arm of the patient in a direction away from the midsagittal plane during the lower extremity peripheral intervention. Also, a radiation reduction barrier may be placed apart from the left radial base and from the right radial base, the radiation reduction barrier having a radiodense material disposed between the patient and an attending staff member to reduce scatter radiation from the patient in a direction of the staff member during a procedure. In another embodiment, a left radial access, right room operation peripheral intervention system for use with an imaging system may include a base board being configured for connection proximate a table having a left side and a right side corresponding to a left arm and a right arm of a patient; a left radial base attached to the base board and being configured to cushion and stabilize a left arm of a cardiac patient across a midsagittal plane of the patient during a lower extremity peripheral intervention on the table, wherein an attending cardiologist may perform the intervention from the right side of the table; and a radiation reduction barrier spaced apart from the left radial base, the radiation reduction barrier having a radiodense material disposed between the patient and an attending staff member to reduce radiation scattering from the patient in a direction of the staff member. In yet another embodiment, a left radial access, right room operation peripheral intervention system for use with an imaging system may have a base board being configured for attachment proximate a procedure table; a left radial base attachable to the base board and being configured to stabilize a left arm of a patient across a midsagittal plane of the patient during a lower extremity peripheral intervention on the procedure table; a right radial base attachable to the base board and disposed substantially parallel to an operating surface of the procedure table, the right radial base being transradiant and configured to position a right arm of the patient in a direction away from the midsagittal plane during the lower extremity peripheral intervention; a radiation reduction barrier attachable to the base board and spaced apart from the left radial base and from the right radial base, the radiation reduction barrier having a radiodense material disposed between the patient and an attending staff member to reduce radiation scattering from the patient in a direction of the staff member during an imaging procedure; and a radiodense apron releasably connected to the base board. In a further embodiment, a left radial access, right room operation peripheral intervention system for use with an imaging system may include a right radial base having a base board attachable to a procedure table with a right side and a left side corresponding to a right arm and a left arm of a patient, the right radial base being disposed substantially parallel to an operating surface of the operating table, the right radial base board being disposed under the operating surface, the right radial base being transradiant and configured to position the right arm of the patient in a direction away from the midsagittal plane during the lower extremity peripheral intervention; a left radial base in connection with the right radial base board and being configured to stabilize a left arm of a patient across a midsagittal plane of the patient during a lower extremity peripheral intervention on the procedure table; a radiation reduction barrier attachable to a right radial base board under the table surface, the radiation reduction barrier spaced apart from the left radial base and from the right radial base, the radiation reduction barrier having a radiodense material disposed between the patient and an attending staff member to reduce radiation scattering from the patient in a direction of the staff member during an imaging procedure; and a radiodense apron releasably connected to the base board. An exemplary method for left radial access and right room operation peripheral intervention system may include joining a left radial base proximate a procedure table having a left side corresponding to a left arm of a patient and a right side corresponding to right arm of a patient; stabilizing the left arm of a patient across a midsagittal plane of the patient with the left radial base; joining a radiation reduction barrier proximate the right side of the procedure table spaced apart from the left radial base, the radiation reduction barrier having a radiodense material disposed between the patient and an attending staff member; and performing a lower extremity peripheral intervention on the procedure table through the left arm of the patient from the right side of the operating table. Additional aspects of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variations to the specifically illustrated, referred and discussed features and elements hereof may be practiced in various embodiments and uses of the disclosure without departing from the spirit and scope of the subject matter. Variations may include, but are not limited to, substitution of equivalent means, features, or steps for those illustrated, referenced, or discussed, and the functional, operational, or positional reversal of various parts, features, steps, or the like. Those of ordinary skill in the art will better appreciate the features and aspects of such variations upon review of the remainder of the specification. Detailed reference will now be made to the drawings in which examples embodying the present subject matter are shown. The detailed description uses numerical and letter designations to refer to features of the drawings. The drawings and detailed description provide a full and written description of the present subject matter, and of the manner and process of making and using various exemplary embodiments, so as to enable one skilled in the pertinent art to make and use them, as well as the best mode of carrying out the exemplary embodiments. However, the examples set forth in the drawings and in the detailed description are provided by way of explanation only and are not meant as limitations of the disclosure. The present subject matter thus includes any modifications and variations of the following examples as come within the scope of the appended claims and their equivalents. Turning now to FIG. 1, a trans-radial access catheter operating system is designated in general by the number 10. The system 10 is structured in general for left radial access, right room operation by permitting a doctor to remain on a right side of an operating table while simultaneously reducing radiation in inferior and superior regions relative to the operating table. The system 10 broadly includes a right radial base or deck 12, a base board, main base or platform 14, a superior radiation shield or barrier 16, which may include a unitary or insertable radiation reducing material 48, a left radial base, wall or fence 18, an inferior right radiation apron or curtain 20, and an inferior left radiation apron or curtain 22 (see FIG. 2). The exemplary components of the trans-radial access catheter operating system 10 may be made from durable, water-resistant, reusable materials that are susceptible to high pressure and/or heated sterilization and may also be constructed to block or permit passage of radiation. In the example of FIG. 1, a cardiac or lower peripheral patient 3 is placed on a procedure or operating table 5 that hosts the main platform 14. The deck 12, the radiation shield 16, and the left radial base 18 may be in connection with the platform 14 or attached to the platform 14 via mechanical connections that may include slots or holes 36 formed in a first or top side 32 of the platform 14. As shown, a right arm of the cardiac patient 3 may be laid along a first surface or first arm side 24 opposite a second surface or connection or bottom side 26 of the right radial base 12. Also shown, a first or interior face or side 54 of the fence 18 positions a left arm of the patient 3 across a midsagittal plane or center line 70 of the patient 3 (see FIG. 2). A board or brace (not shown) may be provided to stabilize and immobilize the arm for preliminary access procedures and until the fence 18 is positioned. As will be explained in greater detail below, the fence 18 may be adjusted relative to the platform 14 and to accommodate the patient 3. A handle 62 may be provided to carry and position the left radial base 18. As further shown in FIG. 1, one or more medical instruments 7 (shown schematically) are introduced through a sheath 9 in the stabilized left arm. X-ray or fluoroscopic imaging systems or other types of medical imaging systems are used by a doctor or staff on the right side of the table 5, also referred to as the staff side or patient right arm side, to visualize on appropriate equipment or monitor 11 the positioning of the medical instruments 7 in the patient 3. The exemplary deck 12 in FIG. 1 is made of transradiant or radiotransparent material such as high density polyethylene (HDPE). Thus, the deck 12 is constructed to permit passage of X-ray photons 1 during imaging of a patient, for example, to assess blockages in the patient during a procedure. As shown, the first surface 24 of the deck 12 is sufficiently large, as preferred by most doctors and staff, to accommodate surgical instruments including wires, guides, balloons and stents 7, many of which may exceed 360 centimeters (cm) in length and require the space provided by the surface 24 in order to more easily access and manipulate these instruments. Also, the X-ray or ionizing radiation 1 (shown schematically in FIG. 1) passes through the patient 3, but the ionizing radiation material 48 of the radiation shield 16 blocks or attenuates any rays 1 that are scattered by the patient's body toward staff working with the instruments 7 on the right arm side of the table 5. FIG. 2 most clearly shows the left radial base or fence 18 located opposite the vertically disposed radiation barrier 16. As shown, the fence 18 may be releasably attached to the base board 14 via the apertures 36, which are located in this example above a portion of the radiation curtain 22 with the operating table 5 located between the body 14 and the curtain 22. As a 4-way arrow 72 indicates, the fence 18, like the radiation barrier 16, may be adjusted toward or away from the patient 3 to account for a smaller or larger patient 3 such that the left arm remains in position across the midsagittal plane 70. FIG. 3 particularly shows a portion of the trans-radial access operating system 10 from the right side of the procedure room. As introduced, the system 10 may include the right radial base 12, the main platform 14, the radiation barrier 16, the left radial base 18, and the right radiation apron 20. Here, the radiation barrier 16 may be hollow to allow for insertion of the radiation attenuating material 48. The material 48 may be lead, antimony, tin, barium, bismuth, cesium, tungsten, or any suitable material to reduce scatter radiation. The exemplary lead 48 may be about 1/16 of an inch or about 1.58 mm in thickness and sufficiently radiodense to absorb, inhibit, attenuate, or block ionizing radiation emanating from a patient being x-rayed, i.e., scatter radiation. FIG. 3 further shows that the right radial base 12 and the curtain 20 may be mated with the main platform 14. Alternatively, the right radial base 12 may be unitarily formed with the main platform 14. Moreover, the radiation barrier 16 may include latches, hinges, spring elements or the like 74 that permit folding of the barrier 16 down and over either the right radial base 12 or the platform 14 for patient positioning or for set-up and storage. Here, the barrier 16 may also include an angled area or cut-out 76 to permit passage of a patient's arm to the base 12 (compare, e.g., FIG. 1). An area 80 is established between the angle 76 and the base 12 that is sufficiently large for the patient's arm but not so considerable as to reduce the effective radiation reduction area of the barrier 16. The surface area 80 also provides the physician with a large, stable work surface. Also shown in this example, the base 12 is angled or has an angled area 78 to allow for a C-Arm of x-ray equipment for proper angulation. However, the deck 12 is not limited to the exemplary embodiment in FIG. 3 and may be constructed with a different surface area or geometries, including a lip at area 78 to secure surgical instruments on the deck 12. With continued reference to FIG. 3 as well as FIG. 4, the right radiation apron 20 may be attachable to the platform 14 via brackets or connection devices 40. The curtain 20, similar to the radiation barrier 16, may be made of radiation absorbing or reducing material 68 such as lead, antimony, tin, barium, bismuth, cesium, tungsten, and the like. In this example, the curtain 20 includes a series of pockets or sleeves 66 into which respective material slabs or inserts 68 are placed. This arrangement may be preferred to a solitary lead (Pb) apron, for instance, in order to reduce the weight of the curtain 20 when it is being attached to the deck 12 or the platform 14; to wash the curtain 20 more easily; and/or to replace the inserts 68 with different or thicker radiodense materials as needed. Turning now to FIG. 5 and its side and end views in FIGS. 5A-5D, the base board 14 as briefly introduced is most clearly shown. As noted, the board 14 may be unitarily constructed with the right radial base 12 but in this example, a series of slots or holes 36 in the first or top side 32 extend through the second or bottom side 34 to permit component placements tailored to accommodate different sized patients. As shown, the board 14 may include a radiation reducing layer or insert 38 on or within the board 14 that sits under the operating table (not shown) but does not interfere with patient imaging. This insert 38 may be positioned within and between radiation curtains (see, e.g., 120, 122 in FIG. 8). In one aspect, the insert 38 may be layered into the base board 14. Also shown in FIG. 5, the board 14 may include curtain or apron brackets or holders 44 that may have horizontally oriented apertures 44 or vertically oriented apertures 46 for attaching the curtains 20, 22 (see, e.g., FIGS. 1 and 2). FIG. 6 most clearly shows the radiation barrier 16 as in FIG. 3. As noted above, the barrier 16 may be constructed entirely from radiation attenuating material 48, or the barrier 16 may be hollow for insertion of the material 48. A handle 52 may be provided for carrying the barrier 16 and for manipulating its installation and removal from the base board 14 or procedure table 5 as previously introduced. In this example, the radiation barrier 16 may include one or more connectors such as L-shaped tabs 58. These connectors 58 are inserted at an angle into the slots 36 as shown in FIG. 1 and the barrier 16 is then pressed or snapped into place substantially perpendicular to the operating table 5. The handle 52 may be used to quickly pull the barrier 16 up and out of the slots 36 to adjust the barrier 16 or for cleaning and storage. With reference to FIGS. 7A and 7B, the left radial base 18 of the system 10 is shown most clearly. Here, the base 18 includes a first, staff, or patient side 54 and a second or outer side 56. The handle 62, briefly introduced above, is for transporting and positioning the base 18. As shown, the left radial base 18 may include one or more tabs or inserts 58 for insertion through the holes 36 of the board 14 (see, e.g., FIG. 5). In this example, the inserts 58 are L-shaped with a lower portion having a rectangular shaped extension. This construction permits insertion into the holes 36 at an angle and once in place, the base 18 is pushed down and in contact with the board 14 to lock the base 18 in place. Due to the pressure to be exerted by a patient's left arm against the base 18, a brace, block or step 64 may be included on either or both sides 54, 56 to assist with stability. Also on the patient side 54, an arm rest, cushion, pad or padded projection 60 is provided which faces in a direction of the patient. The arm rest 60 ensures that the left arm, particularly the left wrist, crosses the midsagittal plane 70 (see, e.g., patient 3 in FIG. 2) and can also provide padding for the comfort and protection of the arm of the patient in a manner that promotes proper wrist supination to allow for safe and efficient access to the patient's right artery. In the embodiment shown in FIG. 8, a trans-radial access system is designated in general by the number 110. The system 110 is designed for left radial access, right room operation as it permits a doctor to remain on a right side of a procedure table while simultaneously reducing scatter radiation to the doctor emanating from inferior and superior regions relative to the table, i.e., areas respectively above and below the table 5. The system 110 generally includes a right radial base or platform 112 having an arm surface 124, a radiation shield or barrier 116, which may include a unitary or insertable radiation reducing material 148, a left radial base, wall or fence 118 with an arm cushion 160 and a stand 164, a right radiation apron or curtain 120, and a left radiation apron or curtain 122. The exemplary components of the trans-radial access system 110 may be made from durable, reusable materials that are susceptible to high pressure and/or heated sterilization and may have radiation attenuation or blocking characteristics or alternatively, may permit passage of radiation. As FIG. 8 shows, the radiation shield 116, the left radial base 118, and the radiation aprons 120, 122 may be connected to the platform 112 via connecting devices or components 140, although other attachment means may be used in the alternative or in addition to mechanisms 140, such as snaps, snap-in ball joints, or the like. FIG. 8 also shows that the radiation shield 116 may substantially perpendicular to the platform 112 and may have a tunnel or interior compartment 170 in which a radiation insert 148 may be housed. The insert 148 may be extended away from the table 5 to increase the height or width of the insert 148 as needed, such as by telescoping or unfolding sections of the insert 148. In this example, the insert 148 is a radiation absorbing material such as lead, cadmium, rhodium, or the like. In the case of an unusually large patient, a portion of the insert 148 may be extracted from the compartment 170 and pulled up and away from the table 5 to increase a height of the radiation shield 116 to protect a doctor or staff from radiation being scattered from a patient's body during x-ray or other medical imaging. Turning to FIG. 9, an inferior radiation shield or drape is designated by the number 220. The drape 220 may be attached to a base or main board 214 and may be divided into multiple sections such as sections 220A and 220B. Here, the two sections 220A, 220B overlap one another at area 272. More particularly, the sections 220A, 220B each have loops or other connectors or attachments 274 that are in connection with bars, rods, or other connection devices 240A, 240B. The rod 240A may be inserted or connected to a swivel assembly 276 that permits rotation of at least one of the sections 220A, 220B from about 0 to 45 degrees relative to the base board 214. For instance, the assembly 276 may include an upper portion or section 276A and a lower section 276B. The rod 240A may be inserted into the lower section 276B while the other bar 240B may be stationary or fixed and connected to upper portion 276A and to another connection point or device 278. Also shown, a drive handle 280 may be provided for a technologist to arrange the adjustable components of the system, such as by rotating section 276B relative to section 276A in order to move drape 220A. FIG. 9 further shows that the drape sections 220A, 220B may be constructed with sections, sleeves or pockets 266 to receive insertable lead (Pb) boards 268 (shown in phantom) or other radiation attenuating or blocking materials suitable to block radiation. More specifically, the insertable boards 268 may be radiodense, radiation absorbing or reducing material such as lead, antimony, tin, barium, bismuth, cesium, tungsten, and the like and may be from about 1/16 inch to about ¼ inch in thickness. FIG. 10 most clearly shows the rod 240A in connection with the swivel assembly 276 to permit rotation of the rod 240A (and therefore curtain section 220A shown in FIG. 9). As shown, the rod 240A may be adjusted, swiveled or rotated from about zero degrees to about 45 degrees as depicted by angle 282 relative to the base board 214. Further shown, the bar 240B may be attached to or inserted into the assembly 276 as well as the device 278. This adjustable arrangement may provide further scatter radiation protection to staff standing in a direction nearer the device 278. The overlap provided at area 272 (see FIG. 9) will block scatter radiation with the rod 240A swiveled outward. Introduction On Jun. 22, 2013, a testing service conducted a radiation scatter survey in a heart catheterization room on a prototype based on the embodiments of the present disclosure; i.e., a left radial access right room setup peripheral interventional platform designed to allow a physician to perform lower extremity peripheral, heart catheterizations and pacemaker procedures while simultaneously reducing scatter radiation exposure to the cardiologist and the procedure staff such as the technologist. The purpose of the survey was to determine the percentage and effectiveness of the prototype to reduce scatter radiation levels to the cardiologist and the procedure staff. Equipment and Set-Up. The x-ray unit used for the survey was a GE Innova 2100. Cardio mode was selected on the unit with indicated techniques of 60 kvp, 4 mA, 0.5 mm Cu filtration, and a field of view (FOV) of 20 cm. Radiation scatter readings were taken using a Victoreen and Inovision digital ion chamber in the exposure rate mode, using a five second exposure time. To duplicate a patient, a phantom consisting of a square plastic container with 23 cm of water was used as the radiation scatter medium. Measurements and Test Results. The radiation measurements were made at the normal location [right side of operating table] for the cardiologist and the technologist with traditional radiation shielding in place and with the addition of the prototype. The radiation measurements were taken at each position at the following strategic body locations: eyes, chest, waist, and knees. Radiation measurements were also taken at five different C-arm angle positions typically used in heart catheterization procedures. As shown in detail in FIG. 11 (parts 11A and 11B), the test results indicated an overall exposure rate reduction to the technologist by 50.8% and to the cardiologist by 64.4%. More specifically, radiation reduction to the cardiologist at eye level was 39%; at chest level: 71.7%; at waist level: 76.7%; and at knee level: 70.45%. In short, radiation reduction exposure to attending staff may be reduced by between about thirty percent to about seventy-seven percent over a system that lacks the radiodense aspects described herein. Significantly reduced radiation exposure to procedure staff not only protects these professionals from unnecessary scatter radiation, but such reductions increase their procedure room longevity based on parameters mandated by federal and state radiation exposure limits. While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.
062531638	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal and a process for self-diagnosis or supervision and the portable object of the microcircuit card or so called "smart card" type used in a process or terminal or reader of this type. Such portable objects comprise a central processor, a program memory containing an executable code constituting the operating system, a non-volatile and programmable data memory, and one or more communication interfaces. The terminal is a device equipped with an interface compatible with the portable object; and include a central processor and software that is capable of communicating and operating on the data issuing from the non-volatile data of the portable object. 2. Description of Related Art In general, terminals adapted to cooperate with microcircuit cares, i.e. smart cards are equipped with specific software corresponding to their utilization, for example portable payment terminals are equipped with an operating program of the banking type. This software is produced or specified by the institution that manages this application; in the example cited, this is a banking institution. The institution that manages the application is generally not the manufacturer of the terminal; but purchases or orders the manufacture of the hardware part, that is the terminal, and it installs the specific program into it in order to configure its terminal for its own application. The banking institution thereby has the advantage of purchasing a standard, and therefore inexpensive, product and adapting it according to its needs. The manufacturer offers a basic model which can be suited to a plurality of applications, which enables it to expand its market. An institution running a given application may wish to use a plurality of card reader terminal models. Because it is not desirable to develop application software for each of the terminals manufacturers generally implement a basic software layer that ensures the interface between the hardware and the application software. This software layer enables the same application software to be adapted to different terminals. One way to do this is to create an interpreter so that the institution can develop its application in a well-known high-level language, nearly independent of the constraints of the hardware. Another way to do this is to set up a low-level software layer that manages all the hardware input-outputs and to make available to the operating institution a library of primitives that the application software will call. In all cases, it must be possible to validate or to test the terminal in its entirety. The validation or testing of the terminal must take into account both parts: the hardware with its basic software and the application software. A self-test makes it possible to verify each device of the terminal. The self test is generally constituted by a routine implemented in the basic software. The testing of the application software must be done in the laboratory. Accordingly, it is important in this type of application to properly verify the operation of the program before it is placed in service. However, due to the multiplicity of cards available for use a very large number of specific cases are not reproducible in the laboratory. SUMMARY OF THE INVENTION The object of the subject invention is to validate or test, under normal usage conditions, the operation of application software. To this end, the invention relates to a terminal equipped with an application program, with at least one output constituted either by a display, or by a printer, or by a communication network, or by a portable object, and cooperating with a portable object equipped with a non-volatile memory area containing data, and comprising a reader which communicates with this portable object, characterized in that the device comprises means for reading or storing in its memory diagnostic or supervisory data and means for sending these data to outputs specified as a function of information supplied by the self-diagnostic or supervisory data following the execution of at least one task of its application program in connection with the portable object. According to another of the subject invention, the means for sending the self-diagnostic data are activated a certain number of times. According to another of the subject invention, the means for sending the self-diagnostic or supervisory data comprise means for writing in the portable object connected to the device. According to another of the subject invention, the self-diagnostic or supervisory data are constituted by at least one triplet of information corresponding, for a first piece of information, to a predetermined task of the application program, for the second piece of information to a data type correlated to the task executed and to be presented to an output, and for the third piece of information to a value for specifying the output to which the data type must be presented among those present in the terminal. According to another of the subject invention, the device has a means for testing for the presence of self-diagnostic or supervisory data in a portable object and for initiating the reading and the storage of these data in a specific area ZTD of the memory of the terminal. According to another of the subject invention, the terminal comprises means for entering self-diagnostic or supervisory data into a portable object. Another object of the present invention is to provide a process for supervising the operation of a terminal or for the self-diagnosis of a terminal. This object is achieved due to the fact that the self diagnostic or supervisory process, from at least one triplet of information corresponding, for a first piece of stored information, to a predetermined task of an application program executed either by a portable object or by a terminal, for the second piece of information to a data type correlated to the task executed and to be presented to an output, and for the third piece of information to a value for specifying the output among those present in the terminal, is characterized in that it is comprised of: executing a task of the application program in the terminal; PA1 testing an indicator either in the terminal or in the portable object to determine whether a self-diagnostic or supervisory function is operational, then in the case of a positive response; PA1 searching in the memory of either the portable object or the terminal to see if among the triplets of information stored there is a triplet wherein the first piece of information corresponds to the predetermined task executed by the terminal or the card; PA1 sending to-the output specified by the triplet thus read the value of the datum correlated to the task executed and to be labelled by the second piece of information in the triplet. According to another of the subject invention, the process comprises a testing step comprised of determining whether there are other tasks to be executed, and following the execution of these tasks, searching for all of the triplets of information corresponding to the execution of this task. According to another of the subject invention, the process comprises a step for reading from a portable object storing in its nonvolatile memory a plurality of triplets and a step for storing these triplets in a non-volatile memory area of the terminal, followed by a step for activating an indicator of an active self-diagnostic or supervisory function. According to another of the subject invention, the process comprises a testing step for determining whether the portable object is a card specific to the self-diagnostic or supervisory function or a so-called general-purpose card. According to another characteristic the self-diagnostic or supervisory data are constituted by a fourth field of information containing in the portable object initially the write address (Adr-V), the number of octets to be written (Nb-V), and after the self-diagnosis operation, the value to be written (Val). Another object of the present invention is to provide a portable object that can be used with a terminal and the self-diagnostic or supervisory process as described herein. This object is achieved due to the fact that the portable object is a microprocessor card operating by means of an operating system stored in the card and comprising a non-volatile memory containing at least one triplet of information in a predetermined area of this non-volatile memory whose location is defined by address fields located in the memory part used to store the operating system. According to another of the subject invention, the part of nonvolatile memory used to store the operating system also comprises, in a memory field, a piece of information constituting a counter of utilizations of the self-diagnostic function. According to another of the subject invention, the memory area storing the operating system comprises a field which makes it possible to store an indicator of the activation of the self-diagnostic or supervisory function.
	summary
	claims	1. An apparatus comprising:a cylindrical pressure vessel including an upper vessel section, a lower vessel section, and a mid-flange, the upper vessel section and the lower vessel section being joined by the mid-flange;a cylindrical central riser disposed concentrically inside the cylindrical pressure vessel and including an upper riser section disposed in the upper vessel section and a lower riser section disposed in the lower vessel section;a reactor core comprising fissile material disposed inside the cylindrical pressure vessel in the lower vessel section;control rod drive mechanism (CRDM) units controlling control rod insertion actively into the reactor core, the CRDM units being disposed inside the cylindrical pressure vessel above the reactor core and in the lower vessel section with no vertical overlap between the upper vessel section and the CRDM units;a riser transition section disposed between the upper riser section and the lower riser section, the riser transition section being connected to the mid-flange by gussets having first ends welded to the mid-flange and second ends welded to the riser transition section, the gussets being angled downward such that the riser transition section is disposed below the mid-flange;a CRDM support plate disposed below the riser transition section and supporting the CRDM units; andtie rods suspending the CRDM support plate from the mid-flange. 2. The apparatus of claim 1, further comprising:steam generators disposed inside the cylindrical pressure vessel and entirely in the upper vessel section. 3. The apparatus of claim 2, wherein the steam generators are secured to the upper vessel section such that the upper vessel section and the steam generators can be lifted as a unit. 4. The apparatus of claim 1, wherein upper ends of the tie rods connect with the riser transition section to suspend the CRDM support plate from the mid-flange via the riser transition section and the gussets. 5. The apparatus of claim 1, further comprising:guide frames disposed between the CRDM units and the reactor core and guiding control rods into the reactor core;a lower hanger plate supporting the guide frames; andlower tie rods suspending the lower hanger plate from the CRDM support plate. 6. The apparatus of claim 1, further comprising:guide frames disposed between the CRDM units and the reactor core and guiding control rods into the reactor core; anda lower hanger plate supporting the guide frames; andwherein the tie rods further connect with the lower hanger plate such that the lower hanger plate is also suspended from the mid-flange by the tie rods. 7. The apparatus of claim 1, further comprising:power delivery cabling including at least one of:(1) a plurality of electrical feedthroughs passing through the mid-flange and mineral insulated (MI) cables extending from the electrical feedthroughs to the CRDM units to conduct electrical power to the CRDM units; and(2) a plurality of hydraulic feedthroughs passing through the mid-flange and hydraulic cables extending from the hydraulic feedthroughs to the CRDM units to conduct hydraulic power to the CRDM units. 8. The apparatus of claim 7, wherein at least one of MI cables and hydraulic cables of the power delivery cabling are embedded in or secured to the CRDM support plate such that the CRDM support plate is a power distribution plate. 9. The apparatus of claim 1, further comprising:an annular pump plate having an outer circular perimeter connecting with the mid-flange and an inner circular perimeter connected with the riser transition section; andreactor coolant pumps disposed entirely inside the cylindrical pressure vessel and mounted on the annular pump plate. 10. The apparatus of claim 1, further comprising:reactor coolant pumps mounted on the upper vessel section. 11. An apparatus comprising:a cylindrical pressure vessel including an upper vessel section, a lower vessel section, and a mid-flange, the upper vessel section and the lower vessel section being joined by the mid-flange;a cylindrical central riser disposed concentrically inside the cylindrical pressure vessel and including an upper riser section disposed in the upper vessel section, a lower riser section disposed in the lower vessel section, and a riser transition section disposed between the upper riser section and the lower riser section, the riser transition section being connected to the mid-flange;a reactor core comprising fissile material disposed inside the cylindrical pressure vessel in the lower vessel section;control rod drive mechanism (CRDM) units controlling control rod insertion actively into the reactor core, the CRDM units being disposed inside the cylindrical pressure vessel above the reactor core and in the lower vessel section with no vertical overlap between the upper vessel section and the CRDM units;a CRDM support plate disposed below the riser transition section and supporting the CRDM units; andtie rods suspending the CRDM support plate from the mid-flange. 12. The apparatus of claim 11, further comprising:steam generators disposed inside the cylindrical pressure vessel and entirely in the upper vessel section. 13. The apparatus of claim 12, wherein the steam generators are secured to the upper vessel section such that the upper vessel section and the steam generators can be lifted as a unit. 14. The apparatus of claim 11, further comprising:gussets connecting the riser transition section to the mid-flange, the gussets having first ends welded to the mid-flange and second ends welded to the riser transition section. 15. The apparatus of claim 14, wherein the gussets connecting the riser transition section to the mid-flange are angled downward such that the riser transition section is disposed below the mid-flange. 16. The apparatus of claim 11, wherein upper ends of the tie rods connect with the riser transition section to suspend the CRDM support plate from the mid-flange via the riser transition section and the gussets. 17. The apparatus of claim 11, further comprising:guide frames disposed between the CRDM units and the reactor core and guiding control rods into the reactor core;a lower hanger plate supporting the guide frames; andlower tie rods suspending the lower hanger plate from the CRDM support plate. 18. The apparatus of claim 11, further comprising:guide frames disposed between the CRDM units and the reactor core and guiding control rods into the reactor core; anda lower hanger plate supporting the guide frames; andwherein the tie rods further connect with the lower hanger plate such that the lower hanger plate is also suspended from the mid-flange by the tie rods. 19. The apparatus of claim 11, further comprising:an annular pump plate having an outer circular perimeter connecting with the mid-flange and an inner circular perimeter connected with the riser transition section; andreactor coolant pumps disposed entirely inside the cylindrical pressure vessel and mounted on the annular pump plate. 20. The apparatus of claim 11, further comprising:reactor coolant pumps mounted on the upper vessel section.
	description	The invention relates to an arrangement for generating a proton beam and an installation for transmutation of nuclear wastes, particularly from nuclear reactors. It is known that the transmutation of nuclear wastes from nuclear reactors needs to deposit a large amount of neutrons and gamma photons on hazardous nuclear isotopes. The conventional approach is to use fast neutrons generated by fast breeding reactors or a dedicated high power and high energy accelerator to bombard a spallation heavy weight target to produce high flux of neutrons which will induce transmutation of these isotopes. A conventional arrangement for transmutation of nuclear wastes has the short-comings that it is very bulky and expensive. Its size may exceed the one of the nuclear reactor itself. The invention has the object to overcome these shortcomings. For reaching this object, the arrangement proposed by the invention is characterized in that it is constituted by a laser driven accelerator of protons adapted to produce a beam of relativistic protons of 0.5 GeV to 1 GeV with a current in the order of tens of mA, such as a current of 20 mA. According to a feature of the invention, the arrangement is characterized in that it comprises a laser pulse source adapted to produce a beam of short pulses having a duration of hundreds of femtoseconds and an intensity greater than 1023 W/cm2 with a high-average power of the order of tens of MW and a proton target on which the laser beam is focused on. According to another feature of the invention, the arrangement is characterized in that the duration of the laser pulses is in the order of 30 femtoseconds. According to still another feature of the invention, the arrangement is characterized in that the high-average power is in the order of 20 MW. According to still another feature of the invention, the arrangement is characterized in that it comprises a laser pulse oscillator producing ultra-short pulses having a duration in the order of tens of femtoseconds and an energy in the order of nanojoules and a single mode optical fiber amplifier device into which the produced laser pulses are fed in, comprising a multitude of optical fibers in view to form a coherent amplification network system. According to still another feature of the invention, the arrangement is characterized in that said coherent amplification network system comprises a series of successive amplifier stages each comprising a bundle of single mode fiber amplifiers, in which the fibers are spaced from one another in view to allow passage of a cooling medium there between, the bundle of one stage comprising fibers which have been obtained by splitting of the fibers of the preceding stage bundle. According to still another feature of the invention, the arrangement is characterized in that in the downward end the portion of the coherent amplification network, each fiber comprises two fiber sections, an amplifying fiber section belonging to the last amplifier stage in which the fibers are separated from one another for cooling reasons and a transport fiber section made of very low loss fiber, the transport fibers allowing to transform the great diameter bundle of the amplifier stage into a small diameter output bundle where the fibers are kept as close as possible from each other to make the overall output pupil diameter as reduced as possible. According to still another feature of the invention, the arrangement is characterized in that the proton target is a solid target formed by a film of a substance such as hydrogen, helium or carbon. According to still another feature, the laser pulses source is adapted to produce laser pulses having a repetition rate in the order of Khz, such as 10 KHz. The installation for transmutation of nuclear wastes is characterized in that it comprises the arrangement for producing the beam of relativistic protons and a spallation target for producing a beam of neutrons of 0.5 GeV to 1 GeV, which is directed towards nuclear waste, said spallation target being irradiated by the ultra-relativistic proton beam. In accordance to an advantageous feature, the spallation target is a liquid target of Pb—Bi. According to another feature, the installation is characterized in that the spallation target comprises an entrance window of high-stress steel and a cylindrical tube filled by a liquid of Pb—Bi alloy, the liquid alloy being used as cooling medium. The invention will be described below in its application to transmutation of nuclear waste. This application however serves only as a non-exclusive example. It is to be noted that the invention covers all applications using a beam of relativistic protons obtained by the laser based method proposed by the invention. As shown on FIG. 1, an installation for transmutating nuclear waste such as waste from nuclear reactors comprises an ultra-relativistic intensity pulse-laser source 1 susceptible to produce a laser beam 2 of ultra-short laser pulses having a duration of for instance 30 femtoseconds (fs) and an intensity greater than 1023 W/cm2 with high-average power of the order of 20 MW, a proton target 3 on which the laser beam 2 is focused on and from which a beam of relativistic protons 4 of 0.5 GeV to 1 GeV with a current for instance of the order of 20 mA is produced. The latter irradiates a spallation target 5, for instance a liquid target of Pb—Bi where neutrons 6 of 0.5 to 1 GeV are spallated from. The neutrons are directed towards the nuclear waste 7 to be transmutated, such as spent nuclear fuel, in order to transmute the waste's radioactive isotope, i.e. lower actinides, into much safer materials or elements with significantly shorter half-lives. With reference to FIGS. 2 to 4, the ultra-relativistic intensity pulse-laser source 1 will be described here-below in a detailed manner. As can be seen on FIG. 2, the source 1 comprises an oscillator 8 adapted to produce short pulses of for instance femtoseconds (fs) duration and energy in the order of nanojoule (nJ). The produced laser-pulse is fed into a single mode optical fiber amplifier arrangement comprising a multitude of optical fibers in view to form a coherent amplification network (CAN) system providing simultaneous high-peak and high-average powers with high efficiency greater than 30%, i.e. the laser beam 2 shown on FIG. 1 which may have an intensity greater than 1023 W/cm2. Concerning the coherent amplification network system reference is made to the publication “Euronnac, May 2012 Meeting CERN”, IZEST, Ecole Polytechnique, Palaiseau of Gerard Mourou and Toshiki Tajima, and to the publication “Coherent Beam Combining of 1.5 μm Er Yb Doped Fiber Amplifiers”, Fiber and Integrated Optics, 27(5) (2008) of S. Demoustier, C. Bellanger, A. Brignon and J. P. Huignard, and of “Collective Coherent Phase Combining of 64 fibers” Opt. Express, 19, Issue 18, 17053-17058 (2011) of J. Bourderionnet, C. Bellanger, J. Primot and A. Brignon. More precisely, the laser-pulse produced by oscillator 8 passes through a pair of diffraction gratings 10 which are represented in form of a boxes the structure of which is precised beneath and which stretch it by about 105 times in a manner known per se. The stretching separates the various components of the stretch pulse, producing a rainbow in time. The pulse after stretching is at the millijoule (mJ) level. The stretched pulses are coupled in a first amplifier stage 13 to a multiplicity of for instance 10 to 100 fibers 14, each constituting a single mode fiber amplifier. Each fiber will amplify the input pulse to the millijoule level. The amplified fibers are kept to form a bundle wherein the amplifying fibers are at a relatively large distance from one another in order to allow efficient cooling by an appropriate cooling medium for evacuating heat produced by the fibers. The same operation is repeated in a second amplifier stage 15 where each fiber amplifier of the first stage 13 feeds a multiplicity of for instance 10 to 100 single mode amplifiers 16 of the same type as the ones of the first stage. Each fiber will amplify the input, which is a corresponding part of the output of the fiber from which it is obtained by splitting, to the millijoule level. The same process is repeated in successive series of amplifier stages, one of which is furthermore shown in 17 on FIG. 2 which comprises a larger diameter bundle of fibers 19 spaced from one another for enabling efficient cooling of the fibers. It results from the foregoing that by splitting and branching each single “seed” pulse a matrix of thousands of lasers is obtained. In each stage of the successive series of amplifier stages, the phase of each pulse is preserved. The very great number of fibers of the last stage, on FIG. 2 the stage 17, are combined and phased with one another so as to form a single pulse, which is compressed by a pair of gratings in a manner known per se. The pulse energy can be now of tens of Joules, the pulse duration corresponding to the initial pulse duration of 30 femtoseconds of the present example. FIG. 3 shows the arrangement of the fibers in the region of the downward end of the fiber architecture. As can be seen, each fiber is realized in two sections, an amplifying section 19 and a transport section 20 made of very low loss fiber 21. The fiber amplifying sections 19 which constitute the last amplifier stage are arranged in a manner to form a great diameter bundle wherein the different sections are sufficiently separated from one another to ensure efficient cooling by means of an appropriate cooling medium. The fiber transport sections 20, since they are very low loss fibers which need no particular cooling allow to transform the great diameter bundle in a small diameter output bundle 21 where the fibers are kept as closed as possible from each other to make the overall output pupil diameter as reduced as possible. The individual laser beams which get out at the ends of the small diameter fibers form a beam 22 of single pulse, after having been phase controlled to be in phase such as described in the before mentioned publication “Euronnac, May 2012, Meeting CERN, the teaching of which is considered to be included therein. Each amplified stretched output pulse is then compressed by means of a second pair of gratings 23 schematically shown on FIG. 2. The resulting pulse has the ultra-short duration of tens of femtoseconds such as of 30 femtoseconds of the original pulse produced by oscillator 9, but its energy is enormous of for instance 30 Joules. Theses pulses are made to hit a parabolic mirror 30 which focuses it on the proton target 3 as can be seen on FIG. 4. The resulting pulse is the high-average power and high-intensity pulse 2 shown on FIG. 1, which is in the ultra-relativistic regime, i.e. greater than 1023 W/cm2. According to FIGS. 1 and 3, these pulses 2 which can be produced at a repetition rate in the order of KHz for instance 10 kHZ, due to the efficient cooling of the single mode fiber amplifiers in their different bundles by means of an appropriate cooling medium, are made to shoot the proton target 3 which can be a solid target made of a substance such as hydrogen, helium and/or carbon, advantageously in form of a film 25. The shooting of the target produces the high-flux 4 of high-energy protons in the range of 0.5 to 1 GeV which is made to impinge on the spallation target 5 in order to be converted in the high-flux of fast energetic neutrons 6 by spallation process induced in the target 5 which is for instance a high-Z material target. It is to be noted that 1 GeV proton produces on the target about 30 neutrons which is a high multiplication factor. The target 5 consists of an entrance window of high-stress steel and a cylindrical tube 27 of about 50 cm filled by a liquid Pb—Bi alloy for neutron production. This liquid alloy can be made to flow and circulate in a dedicated hydraulic circuit to maintain the temperature well below its critical value. Accordingly, the alloy is not only used for neutron production, but also as coolant. By appropriate monitoring the corrosion and the stress in the entrance window as well as of the temperature gradient and the production of H and He in the target assembly, a safe operation of the system is insured. In the conditions described above, the invention allows to produce efficient relativistic protons by shooting the solid target of hydrogen and/or helium within a laser at the density of greater than 1023 W/cm2. In this radiation dominated pressure regime, the momentum is transferred to ions through the electric filled arising from charge separation. In this regime, the proton component moves forward with almost the same velocity as the average longitudinal velocity of the electron component and renders the interaction very efficient, close to 100%. Moreover, the proton energy is a desired energy range between 0.5 and 1 GeV to produce the neutrons with the high-energy in order to achieve the transmutation of the nuclear waste 7. It results from the foregoing that the laser based way to produce neutrons to be directed toward a target of nuclear waste comprises an oscillator for producing ultra-short laser pulses in the order of femtoseconds having an energy in order of millijoules, very far from the level of tens of joules necessary for the targeted application of the invention, such as transmutation of nuclear waste. To this end, the invention proposes to combine a very large number, i.e. 104 or more fibers coherently in the coherent amplification network system described above and shown on the figures. The repetition rate of the laser pulses having the intensity greater than 1023 W/cm2 can be advantageously in the order of tens of kHZ due to the use of fibers having a high surface area and the heat removal ensured by the disposition of the fibers in large diameter fiber bundles wherein they are separated from one another to allow circulation of a cooling medium there between. Since the used single mode fiber amplifiers are the same in each amplifier stage, and are tested telecommunication components, the laser pulse generator arrangement and the installation for transmutating nuclear waste can be realized as relatively cheap and compact apparatus which can be moved to locations where it should be used.
048246077	summary	BACKGROUND OF THE INVENTION The present invention relates to a process for denitrating aqueous nitric acid and salt containing waste solutions. In reprocessing irradiated and spent fuel and/or breeder elements there result aqueous, radioactive waste solutions which carry along a number of salts. Inter alia, these solutions contain actinide salts which must be removed from these solutions before further treatment of the waste solutions is effected, for example for the purpose of solidifying the radioactive fission nuclides. This removal of actinide salts could be done, for example, by precipitation with oxalic acid, if the solubility product of the actinide oxalates, e.g. plutonium oxalate, can be exceeded. However, this is possible only if the nitric acid, which is present in high concentration, is destroyed practically completely. In the past, a series of denitration processes have been proposed to dispose of highly radioactive waste solutions. A few of these processes will be listed here: R. C. Forsman and G. C. Oberg describe, in a US-AEC report from the Hanford Works, HW-79622, October 1963, entitled "Formaldehyde Treatment of Purex Radioactive Waste," a denitration with formaldehyde. S. Drobnik destroys nitric acid with formic acid, as described in German Pat. No. 1,935,273 and corresponding U.S. Pat. No. 3,673,086. L. A. Bray and E. C. Martin disclose denitration with sugar in U.S. Pat. No. 3,158,577. W. Boccola and A. Donato denitrate with phosphorus, as disclosed in German Pat. No. 2,125,915. H. Richter and H. Sorantin describe, in a report of the Austrian Studiengesellschaft fur Atomenergie GmbH (in translation, Study Group for Atomic Energy) (Seibersdorf) SGAE Report No. 2252 ST 23/74, March 1974, the destruction of excess nitric acid in radioactive waste solutions with the aid of glycerin and the subsequent solidification of the residue as alkyd resin. The above-listed processes have the following drawbacks: In denitration with formaldehyde or formic acid, the nitric acid solution and denitration reagent cannot be mixed before the reaction since otherwise the denitration reaction would be too violent during heating. The denitration reagent must be added in measured quantities during the reaction. Separation of excess reagent is fraught with problems. In denitration with sugar, the sugar is added as an aqueous solution, and this adds to the volume of the waste solution. In denitration with phosphorus, the nonvolatile phosphoric acids are formed, inter alia, which remain in the denitrated solution. In denitration with glycerin, the reaction exhibits an induction period as a function of temperature. Here again, the denitration reagent is added in measured quantities during the reaction. SUMMARY OF THE INVENTION It is an object of the present invention to substantially reduce the acid and nitrate content of nitric acid waste solutions. Another object of the present invention is to provide such a process which reduces the total salt content in the waste solution without incurring the danger of violent reactions or an increase in volume of the waste solution. A further object of the present invention is to facilitate the precipitation step following the denitration in which, for example, actinides or other dissolved substances are removed. Additional objects and advantages of the present invention will be set forth in part in the description which follows and in part will be obvious from the description or can be learned by practice of the invention. The objects and advantages are achieved by means of the processes, instrumentalities and combinations particularly pointed out in the appended claims. To achieve the foregoing objects and in accordance with it purpose, the present invention provides a process for denitrating aqueous nitric acid and salt containing solutions, comprising mixing the waste solution at room temperature with ethyl alcohol, and heating the mixture to at least 75.degree. C. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, but are not restrictive of the invention.
039487237	abstract	A device is provided which is installed in a reactor prior to carrying out refueling operations and which accurately locates and isolates a selected core location to permit rapid withdrawal and insertion of fuel subassemblies at that location. A shielded plug designed to cooperate with the refueling apparatus is inserted into an access port in the reactor head. A structural shroud extends down from the plug and carries at its lower end a radially floating, hexagonal spreader tube with mechanisms to rotate it for angular alignment purposes and a linear drive for inserting it into the core. The upper end of the spreader tube serves as a guide for leading the fuel handling apparatus into alignment with the chosen subassembly.
	claims	1. A method for actively cooling a containment vessel having an interior surface and an exterior surface and fuel salt in a molten fuel salt nuclear reactor comprising:flowing cold primary coolant into the containment vessel via an inlet channel at a first portion of the containment vessel, wherein at the first portion of the containment vessel the interior surface of the containment vessel is a wall of the inlet channel, thereby cooling the exterior surface of the first portion;flowing the cold primary coolant into a heat exchanger within the containment vessel and spaced apart from the interior surface of the containment vessel, the heat exchanger discharging cooled fuel salt;routing discharged cooled fuel salt through a fuel salt discharge channel at a second portion of the containment vessel, wherein at the second portion of the containment vessel the interior surface of the containment vessel is a wall of the fuel salt discharge channel, thereby cooling the exterior surface of the second portion;routing cooled fuel salt from the fuel salt discharge channel adjacent to a neutron reflector, thereby cooling the neutron reflector; andwherein the cooled neutron reflector is adjacent to a third portion of the containment vessel such that cooling the neutron reflector indirectly cools the third portion. 2. The method of claim 1 wherein the flowing the cold primary coolant into the containment vessel further comprises:flowing the cold primary coolant through the inlet channel inside the containment vessel thermally connected to the first portion of the containment vessel. 3. The method of claim 1 wherein the flowing the cold primary coolant into the containment vessel further comprises:flowing the cold primary coolant through the inlet channel inside the containment vessel to a heat exchanger coolant inlet adjacent a heat exchanger cooled fuel salt outlet. 4. The method of claim 1 wherein the fuel salt is a mixture of at least one fissile salt and at least one non-fissile salt. 5. The method of claim 1 wherein the fuel salt includes one or more of the following fissile salts: UF6, UF4, UF3, ThCl4, UBr3, UBr4, PuCl3, UCl4, UCl3, UCl3F, and UCl2F2. 6. The method of claim 1 wherein the fuel salt includes one or more of the following non-fissile salts: NaCl, MgCl2, CaCl2, BaCl2, KCl, SrCl2, VCl3, CrCl3, TiCl4, ZrCl4, ThCl4, AcCl3, NpCl4, AmCl3, LaCl3, CeCl3, PrCl3 and/or NdCl3. 7. The method of claim 1 wherein the fuel salt is a mixture of UCl4, UCl3, and one or both of NaCl and MgCl2. 8. The method of claim 1 wherein flowing the cold primary coolant into the containment vessel further comprises:contacting the cold primary coolant with the interior surface of the containment vessel at the first portion of the containment vessel. 9. The method of claim 1 wherein routing the discharged cooled fuel salt through the fuel salt discharge channel adjacent to the second portion of the containment vessel further comprises:contacting the cooled fuel salt with the interior surface of the containment vessel at the second portion of the containment vessel. 10. The method of claim 1 wherein routing cooled fuel salt through the channel adjacent to the neutron reflector further comprises:contacting the cooled fuel salt with the neutron reflector. 11. The method of claim 10 wherein the neutron reflector contacts the interior surface of the containment vessel at the third portion of the containment vessel. 12. The method of claim 3 further comprising:flowing heated primary coolant discharged from the heat exchanger through an outlet channel interior to the inlet channel. 13. The method of claim 1 wherein at least one side of the fuel salt discharge channel adjacent to a second portion of the containment vessel is formed by the interior surface of the containment vessel. 14. The method of claim 1 wherein the first portion of the containment vessel extends from a top of the containment vessel vertically to the heat exchanger cooled fuel salt outlet. 15. The method of claim 1 wherein the heat exchanger is a shell and tube heat exchanger having a plurality of tubes within a shell and the method further comprises:flowing cold primary coolant into the shell of the shell and tube heat exchanger; andflowing fuel salt through the tubes of the shell and tube heat exchanger. 16. The method of claim 1 wherein the primary coolant is NaCl—MgCl2.
062787640	abstract	Replicated x-ray optics are fabricated by sputter deposition of reflecting layers on a super-polished reusable mandrel. The reflecting layers are strengthened by a supporting multilayer that results in stronger stress-relieved reflecting surfaces that do not deform during separation from the mandrel. The supporting multilayer enhances the ability to part the replica from the mandrel without degradation in surface roughness. The reflecting surfaces are comparable in smoothness to the mandrel surface. An outer layer is electrodeposited on the supporting multilayer. A parting layer may be deposited directly on the mandrel before the reflecting surface to facilitate removal of the layered, tubular optic device from the mandrel without deformation. The inner reflecting surface of the shell can be a single layer grazing reflection mirror or a resonant multilayer mirror. The resulting optics can be used in a wide variety of applications, including lithography, microscopy, radiography, tomography, and crystallography.
	summary
040574644	abstract	In a nuclear reactor installation, the reactor building which is closed during the operation of the reactor, is subdivided into two ventilation-wise separate zones, wherein overpressure is maintained in the one zone by transporting filtered air from the first to the second zone. The invention is of interest particularly for pressurized water reactors.
	summary
051174472	claims	1. An image input apparatus comprising: a camera tube including a photoconductive layer onto which an optical image is to be projected, a cathode for emitting an electron beam for scanning said photoconductive layer, and a control electrode for controlling a beam current of said electron beam emitted from said cathode in accordance with a control voltage; and deflecting means for periodically deflecting said electron beam to scan said photoconductive layer, said deflecting means periodically deflecting said electron beam to scan an area outside a restricted scanning area determined by an internal structure of said camera tube; wherein said optical image is to be projected onto said photoconductive layer in the form of an ellipse, and wherein said deflecting means periodically deflects said electron beam to scan a rectangular area in which said ellipse is inscribed. a camera tube including a photoconductive layer onto which an optical image is to be projected, a cathode for emitting an electron beam for scanning said photoconductive layer, a control electrode for controlling a beam current of said electron beam emitted from said cathode in accordance with a control voltage, and a mesh electrode having a frame; and deflecting means for periodically deflecting said electron beam to scan said photoconductive layer, said deflecting means periodically deflecting said electron beam to scan an area outside a restricted scanning area determined by the frame of said mesh electrode. an X-ray source for irradiating an object to be inspected with X-rays to produce an X-ray projection of said object; an X-ray sensor for converting the X-ray projection of said object into an optical image; a television camera including a camera tube having a photoconductive layer onto which said optical image from said X-ray sensor is projected, a cathode for emitting an electron beam for scanning said photoconductive layer, and a control electrode for controlling a beam current of said electron beam emitted from said cathode in accordance with a control voltage, said television camera further including deflecting means for periodically deflecting said electron beam to scan said photoconductive layer, said deflecting means periodically deflecting said electron beam to scan an area outside a restricted scanning area determined by an internal structure of said camera tube; an image processor for processing an image signal output from said television camera; an image memory for storing a signal output from said image processor; and a display for displaying said signal output from said image processor; wherein said optical image from said X-ray sensor is projected onto said photoconductive layer in the form of an ellipse, and wherein said deflecting means periodically deflects said electron beam to scan a rectangular area in which said ellipse is inscribed. an X-ray source for irradiating an object to be inspected with X-rays to produce an X-ray projection of said object; an X-ray sensor for converting the X-ray projection of said object into an optical image; a television camera including a camera tube having a photoconductive layer onto which said optical image is projected, a cathode for emitting an electron beam for scanning said photoconductive layer, a control electrode for controlling a beam current of said electron beam emitted from said cathode in accordance with a control voltage, and a mesh electrode having a frame, said television camera further including deflecting means for periodically deflecting said electron beam to scan said photoconductive layer, said deflecting means periodically deflecting said electron beam to scan an area outside a restricted scanning area determined by the frame of said mesh electrode; an image processor for processing an image signal output from said television camera; an image memory for storing a signal output from said image processor; and a display for displaying said signal output from said image processor. 2. An image input apparatus according to claim 1, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 3. An image input apparatus according to claim 1, wherein said camera tube further includes an electrode disposed near said photoconductive layer, and further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the electrode disposed near said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 4. An image input apparatus comprising: 5. An image input apparatus according to claim 4, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans said area outside said restricted scanning area. 6. An image input apparatus according to claim 4, wherein said optical image is to be projected onto said photoconductive layer in the form of a circle, and wherein said deflecting means periodically deflects said electron beam to scan a square area in which said circle is inscribed. 7. An image input apparatus according to claim 6, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said circle. 8. An image input apparatus according to claim 6, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans an area outside said circle. 9. An image input apparatus according to claim 4, wherein said optical image is to be projected onto said photoconductive layer in the form of an ellipse, and said deflecting means periodically deflects said electron beam to scan a rectangular area in which said ellipse is inscribed. 10. An image input apparatus according to claim 9, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 11. An image input apparatus according to claim 9, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans an area outside said ellipse. 12. An X-ray fluoroscopic and radiographic apparatus comprising: 13. An X-ray fluoroscopic and radiographic apparatus according to claim 12, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 14. An X-ray fluoroscopic and radiographic apparatus according to claim 12, wherein said camera tube further has an electrode disposed near said photoconductive layer, and further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the electrode disposed near said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 15. An X-ray fluoroscopic and radiographic apparatus comprising: 16. An X-ray fluoroscopic and radiographic apparatus according to claim 15, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans said area outside said restricted scanning area. 17. An X-ray fluoroscopic and radiographic apparatus according to claim 15, wherein said optical image from said X-ray sensor is projected onto said photoconductive layer in the form of a circle, and wherein said deflecting means periodically deflects said electron beam to scan a square area in which said circle is inscribed. 18. An X-ray fluoroscopic and radiographic apparatus according to claim 17, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said circle. 19. An X-ray fluoroscopic and radiographic apparatus according to claim 17, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans an area outside said circle. 20. An X-ray fluoroscopic and radiographic apparatus according to claim 15, wherein said optical image from said X-ray sensor is projected onto said photoconductive layer in the form of an ellipse, and wherein said deflecting means periodically deflects said electron beam to scan a rectangular area in which said ellipse is inscribed. 21. An X-ray fluoroscopic and radiographic apparatus according to claim 20, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not reach said photoconductive layer during a period in which said electron beam scans an area outside said ellipse. 22. An X-ray fluoroscopic and radiographic apparatus according to claim 20, further comprising beam current controlling means for generating a control voltage and applying said control voltage to said control electrode to control said beam current of said electron beam such that said electron beam does not collide with the frame of said mesh electrode during a period in which said electron beam scans an area outside said ellipse.
	abstract	The present application discloses an X-ray imaging apparatus for determining a surface profile of an object under inspection that is positioned at a distance from the apparatus. The X-ray imaging system has an X-ray source for producing a scanning beam of X-rays directed toward the object, a detector assembly for providing a signal representative of an intensity of X-rays backscattered from the object, and processing circuitry to determine a time difference between when the X-ray source is switched on and when the backscattered X-rays arrive at the detector assembly. The processing circuitry is adapted to output data representative of the surface profile of the object under inspection.
063109344	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an X-ray projection exposure apparatus used in the manufacture of semiconductor integrated circuits. 2. Description of the Related Art In solid-state devices, such as LSIs (large-scale integrated circuits) and the like, circuit patterns are becoming finer in order to increase the degree of integration and the operation speed thereof. In order to form such fine circuit patterns, reduction projection exposure apparatuses having vacuum-ultraviolet exposure light sources are widely used. The resolution of such a reduction projection exposure apparatus depends on the exposure wavelength .lambda. and the numerical aperture NA of the projection optical system. In conventional exposure apparatuses, an approach of increasing the numerical aperture NA is adopted in order to improve the resolution. However, this approach is now close to the limit of the use because of the resulting reduction in the depth of focus and difficulty in the design and the manufacturing of the dioptric system. Accordingly, an attempt to shorten the exposure wavelength .lambda. is being made. For example, light used for exposure shifts from the g-line (.lambda.=435.8 nm) to the i-line (.lambda.=365 nm) of the mercury lamp, and further to KrF excimer lasers (.lambda.=258 nm). Although the resolution of the apparatus is improved by shortening the exposure wavelength, there is a theoretical limit on the resolution from the wavelength of ultraviolet rays used for exposure. Accordingly, in the extended technique of conventional exposure apparatuses using light, it is difficult to obtain a resolution equal to or less than 0.1 um. Against such a technical background, X-ray reduction projection exposure apparatuses using vacuum-ultraviolet rays or soft X-rays (these two kinds of rays are hereinafter termed "X-rays") as exposure light are attracting notice. SUMMARY OF THE INVENTION It is an object of the present invention to provide a practical X-ray projection exposure apparatus in which the above-described problems are solved. It is another object of the present invention to provide a device manufacturing method having a high productivity using such an exposure apparatus. According to one aspect, the present invention provides an X-ray projection exposure apparatus comprising a mask chuck for holding a reflection X-ray mask having a mask pattern thereon, a wafer chuck for holding a wafer onto which the mask pattern is transferred, an X-ray illuminating system for illuminating the reflection X-ray mask, held by the mask chuck, with X-rays, and an X-ray projection optical system for projecting the mask pattern of the reflection X-ray mask onto the wafer held by the wafer chuck with a predetermined magnification. The mask chuck comprises a mechanism for generating static electricity for attracting and holding the reflection X-ray mask by an electrostatic force. It is preferable that the apparatus further comprises a detection mechanism for detecting an attracting force when attracting and holding the mask on the mask chuck. For example, the detection mechanism comprises a pressure sensor provided on an attracting surface of the mask chuck. It is preferable that the apparatus further comprises means for performing scanning exposure by moving both of the mask chuck and the wafer chuck. For example, the mask chuck holds the mask against gravity. It is preferable that the apparatus further comprises means for changing the electrostatic force for attracting the mask by the mask chuck in accordance with the movement of the mask chuck. It is preferable that the relationship of {(the mass of the mask).times.(acceleration due to gravity+the maximum acceleration of the mask while being moved)/(the maximum coefficient of static friction between the mask and the mask chuck)}.times.(safety factor)<(the attracting force of the mask) is satisfied. It is preferable that a plurality of projections are formed on a mask holding surface of the mask chuck, and the reflection X-ray mask is supported by the plurality of projections. The ratio of the area of contact between the distal ends of the projections and the mask to the entire area of the mask is equal to or less than 10%. It is preferable that the apparatus further comprises means for supplying voids formed between the projections with a cooling gas when the mask is supported on the projections. It is also preferable that the apparatus further comprises a temperature control mechanism for controlling the temperature of the mask chuck. For example, the temperature control mechanism comprises means for supplying the inside of the mask chuck with a temperature controlled medium, and a temperature sensor for detecting the temperature of the mask chuck. It is preferable that the mask chuck comprises a ceramic material or a glass material. It is also preferable that the apparatus further comprises a grounded earth pawl provided at at least a side of the mask chuck for supporting the mask. For example, the reflection X-ray mask has a structure in which the mask pattern, made of an absorbing member, is formed on an X-ray reflecting multilayer film. For example, the X-ray illuminating system comprises a radiation source and a reflecting mirror. For example, the X-ray projection optical system comprises a reduction projection optical system having a plurality of X-ray-reflecting mirrors. According to another aspect, the present invention provides a device manufacturing method comprising the step of transferring a mask pattern onto a wafer using the X-ray projection exposure apparatus having the above-described configuration. According to still another aspect, the present invention relates to a device manufacturing method using an X-ray projection exposure apparatus comprising a mask chuck, a wafer chuck, an X-ray illuminating system, and an X-ray projection optical system. The mask chuck holds a reflection X-ray mask having a mask pattern thereon. The wafer chuck holds the wafer onto which the mask pattern is transferred. The X-ray illuminating system illuminates the reflection X-ray mask, held on the mask chuck, with X-rays. The X-ray projection exposure system projects the mask pattern of the reflection X-ray mask onto the wafer held by the wafer chuck with a predetermined magnification. The mask chuck comprises a mechanism for generating static electricity for attracting and holding the reflection X-ray mask by an electrostatic force. The method comprises the steps of generating static electricity with the mechanism of the mask chuck to hold the reflection X-ray mask with the mask chuck by an electrostatic force, holding the wafer with the wafer chuck, illuminating the reflection X-ray mask with X-rays using the X-ray illuminating system, and projecting the mask pattern of the reflection X-ray mask onto the wafer held by the wafer chuck with a predetermined magnification with the X-ray projection optical system to transfer the mask pattern onto the wafer. The foregoing and other objects, advantages and features of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.
	summary
050842366	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 shown a prior art nuclear reactor core vessel 10 and coolant system 12 connected thereto. The reactor coolant system 12 includes two coolant loops, generally indicated by the numerals 14A and 14B. Each of the coolant loops 14A, 14B includes a single steam generator 16, a pair of high inertia canned motor pumps 18, a single hot leg pipe 20, and a pair of cold leg pipes 22. The pair of pumps 18 in each coolant loop 14A, 14B are hermetically sealed and mounted in inverted positions to the one steam generator 16 in the respective coolant loop. Each pump 18 has an outer casing 24 which is attached, such as by welding, directly to the bottom of a channel head 26 of the steam generator 16 so as to effectively combine the two components into a single structure. The hot leg pipes 20 extend between and interconnect the reactor vessel 10 and the respective steam generators 16 for routing high temperature reactor coolant from the vessel 10 to the steam generators 16. The cold leg pipes 22 extend between and interconnect the pumps 18 and the reactor vessel 10 for routing lower temperature reactor coolant from the steam generators 16 via the pumps 18 back to the reactor vessel 10. Further, a pressurizer tank 28 is connected by a surge line 30 to one of the hot leg pipes 20. Referring to FIG. 2, there is illustrated in greater detail one of the reactor coolant pumps 18. In addition to the outer casing 24, the pump 18 has a central rotor 32 extending axially through the casing 24 and rotatably mounted at its lower end by a pivot pad bearing 34 and at its upper end by a pivoted pad and thrust bearing combination 36. A canned motor 38 is located along the pump rotor 32 between the lower and upper bearings 34, 36. The motor 38 includes a rotor section 40 mounted for rotation on the pump rotor 32 and a stator 42 stationarily mounted about the rotor section 40. An annular cooling water jacket 44 surrounds the motor 38. Cooling coils (not shown) are also provided adjacent the upper thrust bearing 36 for cooling the same. Also, at the upper end of the pump rotor 32 is mounted an impeller 46 which rotates with the rotor 32. The pump casing 24 has a central inlet nozzle 48 in its upper end, a tangential outlet nozzle 50 adjacent the upper end and a passage 51 connecting them in flow communication. The outlet nozzle 50 and impeller 46 are axially displaced from one another, thus the pump casing 24 is of the offset type. Rotation of the rotor 32 and impeller 46 therewith draws water axially through the central inlet nozzle 48 in the pump casing 24 from the steam generator 16 and discharges water tangentially through the outlet nozzle 50 in the pump casing 24 after flow through the passage 51 of the casing 24 to the respective one of the cold leg pipes 22. In such manner, operation of the pumps 18 creates reduced pressure at their inlet nozzles 48 which sucks or draws water from the reactor vessel 10 via the respective hot leg pipes 20 to and through the steam generators 16 and creates increased pressure at their outlet nozzles 50 which pumps water through the cold leg pipes 22 back to and through the reactor vessel 10. Offset Pump Casing Outlet Nozzle of Present Invention Referring to FIG. 3, there is illustrated, in a somewhat simplified form, the offset pump casing 24 with the central inlet nozzle 48, peripheral outlet nozzle 50 and flow passage 51. The outlet nozzle 50 has a generally cylindrical construction which produces an abrupt change in flow area at location 52 where shorter portion 50A of the outlet nozzle 50 connects to the casing 24. FIG. 4 is a diagram showing generally the same circular cross-sectional shapes of spaced portions "A" and "a" of the interior surface 54 of the prior art cylindrical outlet nozzle 50 of the offset pump casing 24 of FIG. 3. Referring to FIG. 5, there is illustrated also in a somewhat simplified form, the offset pump casing 24 with the central inlet nozzle 48 but with its outlet nozzle modified to a converging spout outlet nozzle 56 of the present invention. The converging spout outlet nozzle 56 is composed of first and second wall portions 58 and 60 defined above and below an imaginary plane C extending generally parallel to and offset to one side of the rotation axis D of the impeller 46 (see FIG. 2). As can be determined from FIG. 5 together with the diagram of FIG. 6, the first wall portion 58 extends substantially tangentially to the casing 24 and has a substantially semi-circular or cylindrical shape, whereas the second wall portion 60 has a combined substantially semi-elliptical and semi-conical shape. The exit opening 56A of the outlet nozzle 56 has a substantially circular shape. The semi-conical shape of the second wall portion 60 forms a cone angle of approximately twenty-five degrees. Reference literature reports that a maximum cone angle of thirty degrees was found in experimentation for pipe flows. This same maximum limitation on the cone angle also applies to the cone angle of the converging spout outlet nozzle 56 of the present invention. FIG. 6 is a diagram showing the semi-elliptical shape of portion "B" of the interior surface 56B of the converging spout outlet nozzle 56 and the circular shape of portion "b" of the interior surface 56B. The converging spout outlet nozzle 56 of the present invention of FIG. 5 has a loss coefficient approximately ten times less than that of the prior art cylindrical outlet nozzle 50 of FIG. 3. The flow area at the pump casing outlet nozzle is changed in the converging spout outlet nozzle 56 of the present invention from an abrupt one to a smoother one interfacing with the generally spherical casing body 24. FIG. 7 is a graph comparing the volute and offset type casings in terms of the relationship of flow area versus fluid path length. More importantly, however, FIG. 7 depicts the change from the abrupt to the smoother profile of the graph of the offset pump casing brought about by modification of the prior art cylindrical output nozzle 50 of FIG. 3 to the converging spout outlet nozzle 56 of the present invention of FIG. 5. The cone length L (FIG. 5) is adjustable in order to match the inlet area of the outlet nozzle 56 with the flow area F (FIG. 7) of the casing 24. 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.
	abstract	The system for irradiating patients with charged particles includes a raster scanning irradiation unit with a particle accelerator, a beam guide unit, and a 3D scanning system. It also contains a therapy planning system for generating therapy planning data, which include the energy and number of charged particles per raster point in each layer as derived from the derived dose distribution; a therapy control system, which converts the planning data generated by the therapy planning system into irradiation data and irradiation commands for the particle accelerator, the beam guide unit, and the 3D scanning system. The system further has a plurality of safety devices for ensuring that the therapy planning data have been converted correctly and for verifying the functionality of the system. The plurality of safety devices includes an evaluation unit, which checks the irradiation data and irradiation commands supplied by the therapy control system to the 3D scanning system to verify their therapy-specific plausibility.
	description	THIS INVENTION relates to production of radionuclides. More particularly, the invention relates to radionuclides produced according to the Szilard-Chalmers principle and having a high specific activity. The invention accordingly provides for a method of producing such radionuclides, and extends also to radionuclides produced by the method. The invention also provides for a radionuclide production arrangement. A common cause of complications in the treatment of cancer in patients is metastasis of the cancer, particularly in bone. Metastasis is a condition whereby the cancer spreads from a primary site thereof in the body, such as the breast or prostate, and localizes in another organ, such as bone. Pain and discomfort are common symptoms and side effects of metastatic bone cancer, and usually renders separate therapy or treatment of the cancer at the primary site futile, often resulting in the cancer being fatal to the patient. Palliation of bone pain emanating from metastatic bone disease, is generally effected by radionuclide therapy (RNT), also known as radioisotope therapy (RIT). RNT, or RIT, involves administering a radiation source to a target area, such as bone to which the cancer has spread, thereby to irradiate the target area and to contain cancerous growth in the area. This may serve to reinforce and supplement the separate treatment of the primary cancer. Particularly in the treatment of bone metastasis, radiation sources with short range emission and high specific activity are desired, so as respectively to reduce the exposure of sensitive bone marrow to radiation and to obtain a high anti-tumour effect with limited or minimal radiation dosage, thereby reducing radiation exposure to the rest of the body. It is well known in the field of the invention that high specific activity radionuclides, including metastable radionuclides, can be produced by irradiating a suitable target medium, comprising a target nuclide material, with neutron irradiation so that incident neutrons react with target nuclei in the target nuclide material to effect a neutron (n) absorption—gamma (γ) emission nuclear reaction, also expressed as (n, γ). Resulting metastable radionuclides in the target medium gain high recoil energy from the γ-emission and are ejected or recoiled from the original target lattice, i.e. the target nuclide material. These ejected radionuclides are then captured and trapped in a recoil capture material or medium (RCM), which is provided in close proximity with the target medium, with the ejected radionuclides thus being separated from inactive or cold target nuclei in the target nuclide material. The ejected metastable radionuclides are thus concentrated or enriched, relative to the cold nuclei, in the recoil capture material. This process is generally referred to as the Szilard-Chalmers principle. The recoil nuclei are then recovered from the recoil capture material. The present invention seeks to provide a viable method of producing radionuclides with high specific activity and short range radiation emission using the Szilard-Chalmers principle. Thus, in accordance with the invention, there is provided a method of producing radionuclides, which includes in an irradiation zone, irradiating a target medium, comprising at least a target nuclide material, with neutron irradiation, thereby causing radionuclides to form in the target nuclide material, with at least some of the formed radionuclides being ejected from the target nuclide material; and capturing and collecting the ejected radionuclides in a carbon-based recoil capture material which does not have an empty cage structure at crystallographic level. The target nuclide material may be selected from the group consisting of a pure metal and a metal compound. Preferably, the target nuclide material may comprise a metal compound, including a metal oxide, a metal salt, or an organometallic compound. The metal of the target nuclide material may, in particular, be selected from the group of metal elements in the Periodic Table of Elements extending from scandium (Sc), of atomic number 21, to bismuth (Bi), of atomic number 83, both elements included, with the non-metal elements arsenic (As), selenium (Se), bromine (Br), krypton (Kr), tellurium (Te), iodine (I) and xenon (Xe) thus being excluded. Preferably, the metal may be tin (Sn). In such case, the target nuclide material may thus typically be selected from elemental tin or tin metal, as well as from oxides of tin, including tin(II) oxide (SnO) and tin(IV) dioxide (SnO2). The target nuclide material may instead be selected from salts of tin, including tin(II) chloride (SnCl2), tin(IV) chloride (SnCl4), tin(II) sulphate (SnSO4), and tin(II) nitrate (Sn(NO3)2). The target nuclide material may further instead be selected from organometallic compounds of tin, including tetraphenyl tin, tin(IV)-phthalocyanine oxide, tin(II)-phthalocyanine, and tin(II)-2,3-naphthalocyanine. The carbon-based recoil capture material may be selected from amorphous carbon, carbon allotropes, and mixtures thereof. More particularly, the recoil capture material may be selected from isotropic amorphous carbon; carbon allotropes such as graphite, graphene, carbon nanofoam, carbon black, charcoal, activated carbon and glassy carbon; or mixtures thereof. Isotropic amorphous carbon and carbon allotropes, such as those identified above, are characterized thereby that they do not have, at crystallographic level, so-called empty cage structures which are readily deformed by radiation when exposed to neutron irradiation. The target nuclide material and the recoil capture material may both be in finely divided particulate form, each typically having a mean particle size of at most about 50 nm. Desirably, the target nuclide material may have a mean particle size as small as can be obtained, generally being in the order of about 50 nm to about 10 μm. When both the target nuclide material and the recoil capture material are in particulate from as described above, the method may include mixing the target nuclide material and the recoil capture material. It will be appreciated that, in such an embodiment, the recoil capture material will also be present in the irradiation zone while the neutron irradiation occurs, with the target medium thus comprising both target nuclide material and recoil capture material. It is expected that the ratio in which the target nuclide material and recoil capture material will, in such a case, be mixed, may be determined by routine experimentation and optimization. Conveniently, however, the target nuclide material and recoil capture material may be mixed in a 1:1 ratio, by weight. Irradiating the target medium may include placing the target medium in the path of a neutron flux from a neutron source. In one embodiment of the invention, the neutron source may be nuclear fission products of a nuclear fission reaction taking place inside a nuclear reactor. The method may then include placing the target medium in a position relative to the nuclear reactor where the neutron flux from the nuclear fission products is sufficiently high and has kinetic energy within a range that is compatible with the desired reaction with the target nuclide material. Alternatively, the neutron source may be an accelerator-based neutron source. An example of such a source is the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA. The method may include recovering the captured radionuclides from the recoil capture material. Preferably, recovering the captured radionuclides from the recoil capture material includes treating the recoil capture material with a dilute and/or a concentrated acidic extraction solvent, thereby to form a recoil capture material suspension, and chemically extracting or leaching captured radionuclides from the recoil capture material, to obtain a radionuclide-enriched extraction solvent. Thus, it is envisaged that the recoil capture material may be treated either with a dilute acid or with a concentrated acid or, alternatively, with both a dilute and a concentrated acid, separately from each other, e.g. in the form of a two-step treatment. Particularly when the extraction solvent is a dilute acid, recovery of the captured radionuclides from the recoil capture material may include eluting the captured radionuclides from the recoil capture material by dissolution of the captured radionuclides in the dilute acid. The acid may be selected from hydrochloric acid and ascorbic acid. The acid may also be selected from other mineral or organic acids, including nitric acid, sulfuric acid, fluorosulfuric acid, phosphoric acid, citric acid, oxalic acid, acetic acid, and Meldrum's acid. It will be appreciated that the acid may also comprise a combination of any two or more of the abovementioned acids. Preferably, the acid may be diluted to a concentration of the order of 0.01 mol dm−3 to 10 mol dm−3, typically about 0.5 mol dm−3. The method may include incubating the recoil capture material suspension for a prolonged period, preferably not exceeding the half-life of the product radionuclide. It is expected that such incubation of the recoil capture material would allow for more optimal recovery of the captured radionuclides from the recoil capture material to the elutrate or leachate. By “more optimal recovery” there is meant the procurement of a desired yield of captured radionuclides as measured in terms of its gamma activity and converted into an enrichment factor relative to total tin content in the elutrate. Alternatively, the method may include increasing the rate of elution by selecting appropriate reaction conditions, such as temperature, acidity and acid strength, and/or by using ultrasonic treatment to facilitate dislodgement of the captured radionuclides into the surrounding suspension. It is expected that such reaction conditions would be determinable by routine experimentation. The method may also include maintaining the pH of the recoil capture material suspension sufficiently low to avoid untimely hydrolysis of the extracted radionuclide atoms. Maintaining the pH may include selectively adding dilute acid solutions to the suspension. When the extraction solvent comprises a concentrated acid, the acid may typically be a more corrosive acid than those indicated above. The method may then include dissolving or stripping the recoil capture material in such acids. Such more corrosive acids may include aqua regia, which is a 1:3 volumetric mixture of concentrated nitric acid and hydrochloric acid, chromic acid, hydrofluoric acid, or combinations of these acids. The method may further include, when recovering radionuclides from the recoil capture material by treating the recoil capture material with an acidic extraction solvent, recovering or separating radionuclide-enriched extraction solvent from the recoil capture material by means of centrifugation, vortex separation and/or filtration. Alternatively, recovering the captured radionuclides from the recoil capture material may include treating the recoil capture material with an alkaline extraction solvent. Preferably, the alkali may be sodium hydroxide. In such a case, the radionuclides may typically be extracted in the form of radionuclide metal hydroxides. The method may then include recovering or separating recovered radionuclide metal hydroxides from the recoil capture material, typically by means of centrifuge, vortex separation and/or filtration. Instead, recovering the captured radionuclides from the recoil capture material may include combusting the recoil capture material in oxygen. It will be appreciated that, when the target medium comprises a mixture of recoil capture material and target nuclide material, as hereinbefore described, at least some target nuclide material may also be present when recovering captured radionuclides from the recoil capture material in the fashion hereinbefore described, e.g. in the recoil capture material suspension. Therefore, the method may include, if desired, separating the recoil capture material from the target nuclide material before recovering radionuclides from the recoil capture material. Such separation may be achieved by means of a liquid-liquid extraction process, typically using an organic liquid and an aqueous liquid as liquid-liquid extraction solvents. Preferably, the organic liquid is selected from tetrabromoethane (TBE) and toluene. The aqueous liquid will, typically, be water. At least some of the target nuclide material contained in the recoil capture material suspension may typically be recovered to the aqueous phase. The method may further include immobilizing the target nuclide material-containing aqueous phase in order to separate it from the RCM-containing organic phase. Typically, immobilization of the aqueous phase may be achieved by addition of any suitable natural clay or synthetic crack filler to the recoil capture material suspension, thereby to absorb the aqueous phase. The clay may be selected from clays having a high water absorbing capacity which swell extensively when exposed to water. It is expected that such clays will fill, i.e. immobilize, the aqueous phase before the target nuclide material can settle out. Preferably, the clay may be selected from montmorillonite clays, such as bentonite clays, Ca-bentonite clays, attapulgite, MD-Bentonite and Eccabond-N/Bentonite. The invention extends to radionuclides when produced by the method of the invention. According to another aspect of the invention, there is provided a radionuclide production arrangement, which includes an irradiation zone, in which a target medium comprising at least a target nuclide material is provided; a neutron irradiation source, which is provided in a neutron irradiation relationship with the target medium in the irradiation zone; and a carbon-based recoil capture material, arranged to capture radionuclides which are ejected from the target nuclide material, the carbon-based recoil capture material not having an empty cage structure at crystallographic level. The target nuclide material and the recoil capture material may be as hereinbefore described. The neutron irradiation source may also be as hereinbefore described. The invention will now be described in more detail with reference to the following non-limiting examples. In the examples, tin (Sn) has been selected as the metal for the target nuclide material, particularly because of its preference in the treatment of certain cancers and because activated metastable (m) tin-117 (117mSn) can be easily detected due to its ideal 160 keV gamma emission using conventional gamma detectors. Thus, in the case of tin, high specific activity 117mSn is produced by neutron irradiation of a target medium containing tin-116 (1165n) according to the following (n, γ) nuclear reaction:116Sn(n,γ) 117mSn (1)whereby the resulting radioactive 117mSn nuclei gain high recoil energy from the γ-emission and the 117mSn atoms are thus ejected or recoiled from the original lattice of the target nuclide material. All reagents were of analytical grade and were obtained from Merck KGaA, Darmstadt, Germany and from Sigma-Aldrich Chemie GmbH, Steinheim, Germany. The target medium was selected from combinations of >99% pure SnO, in powder form having a mean particle size of 10 micron powder and SnO2 in nano-powder form, as target nuclide material, and >99% pure carbon in nano-powder form or graphite powder, as recoil capture material. Solutions of ascorbic acid and hydrochloric acid (HCl) were each prepared at a concentration of 0.50 mol dm−3 for extracting recoiled 117mSn atoms from the carbon or graphite recoil capture material, after irradiation, i.e. after the 116Sn(n, γ) 117m Sn reaction (1). Target media were prepared as indicated in Table 1, comprising combinations of 50 mg (0.37 mmol) SnO, or 50 mg (0.33 mmol) SnO2, admixed with 50 mg of carbon nano-powder or graphite powder as recoil capture material. The prepared target media were then sealed in polyethylene capsules. Two targets of each combination of target nuclide material and recoil capture material were prepared: one to be extracted using the 0.50 mol dm−3HCl solution, and the second to be extracted with the 0.50 mol dm−3 ascorbic acid solution. The target media were prepared for irradiation at the nuclear reactor of the Reactor Institute of the Delft University of Technology, Delft, Netherlands (TU Delft). The target media were then irradiated for a period of 10 hours and left to cool over a five day period in order to allow the samples to cool down or decay to lower radiation levels for safer handling and to reduce false counts from short-lived contaminants. The recoiled 117mSn radionuclides were extracted from the carbon or graphite media with the pre-prepared HCl and ascorbic acid solutions. A volume of 10 ml each of the respective acid solutions was added respectively to the irradiated target media, including the polyethylene capsule, which was opened, thereby to form respective suspensions of the target media, comprising the target nuclide material and the capture media, in the acid solutions. A 2 ml sample of each suspension was immediately taken to assay the total target yield or background of dissolved un-irradiated oxides as reference for the enrichment factor, whereafter the volume was topped up with 2 ml of the corresponding acid solution and left to incubate at room temperature, respectively for periods of 0.25 hour, 0.5 hour, 1 hour, 5 hours, 48 hours, and 7 days. At the respective time intervals as indicated in Table 1 below, 2 ml samples of the suspensions were extracted by filtering through a 0.22 μm filter. The 117mSn ions that had been dissolved or leached from the recoil capture material into the acidic solutions were maintained in solution as described hereinbefore and were collected in the filtrate, with the un-reacted, or non-recoiled, stable tin-oxide target nuclide material and the recoil capture material essentially remaining behind in the filter, to be flushed back into the capsule with the 2 ml top-up solution for further leaching. Thus, the filtrate contains a concentrate of the radioactive 117mSn radionuclides enriched relative to any dissolved un-reacted tin oxide. Samples taken after the 7-day incubation period, as identified in Table 1 below, were taken after having placed the recoil capture material suspensions in an ultrasonic bath for 1 hour. Up to the 60 minute sample the suspensions were topped up again to maintain a fixed volume of 10 ml, and were vortex mixed at 15 minute intervals. In a separate set of tests, target media were prepared in triplicate to reproduce the results obtained by ultrasonic treatment. These were incubated for 48 hours at which time samples were taken before and after ultrasound exposure of 1 hour. A second set of samples were taken on day 7 of the trial. The 117mSn activity within the 2 ml samples were then determined by γ-spectroscopy and calculated back to end of bombardment (EOB). These were analyzed at the Instrumental Neutron Activation Analysis (INAA) facility at the Department of Radiation, Radionuclides & Reactors, Faculty of Applied Sciences, Delft University of Technology. For the determination of the specific activity and enrichment factors, the total tin concentration was measured by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) at the appropriate tin wavelength of 189.926 nm. The method of this embodiment of the invention successfully concentrated 117mSn radionuclides in both the graphite as well as the amorphous carbon recoil capture media, achieving for SnO2 an enrichment factor of 34 (as indicated in Table 1), with a specific activity and yield of 2.53 MBq mmol−1 and 0.07%, respectively, in 0.50 mol dm−3HCl solution. On the other hand, SnO yielded lower specific activities, probably due to the relative ease of dissolution of the unirradiated target SnO in the acidic medium used. Acidic solutions were used to maintain low pH conditions for the extraction of the radionuclides from the recoil capture medium, minimizing the chance of hydrolysis of the recoil tin ions and their eventual precipitation, especially for SnO2 (i.e. Sn4+), which would make the recoiled tin and target tin oxide(s) virtually inseparable by filtration. Both the ascorbic acid and HCl are strong reducing agents and minimize the oxidation of the dissolved 117mSn, which could similarly lead to hydrolysis. Ascorbic acid, being a weak acid (pH 2), is less reactive than HCl (pH 0.4). This was considered as being beneficial for achieving higher specific activity, since the stronger HCl also readily dissolves the un-irradiated target oxides, an effect which is even more prominent for SnO, which was about 1000 times more soluble than SnO2 in HCl (Table 1 compared to Table 2). In Table 1, the results of the analysed samples are given for extraction with HCl, while Table 2 below displays the same for extraction with ascorbic acid. For the SnO2 the amount of dissolved tin was generally constant up to about 3 days of incubation. However, SnO was more labile and exhibited a moderate increase in dissolved tin with time. Being an organic acid, the ascorbic acid has an advantage as it allows the carbon or graphite particles to suspend or disperse in solution due to a moderate apolar, hydrophobic effect, thus, allowing for a larger surface area for contact with the acid to effectively extract the recoiled activity. Furthermore, ascorbic acid is reported to act as a complexing agent, which could then bind the extracted 117mSn ions and keep them in solution, in so doing minimizing the hydrolysis of tin and allowing for separation by filtration. Additional control experiments were carried out (Table 3) in which the extraction procedure was repeated using un-irradiated (cold) SnO2 and SnO, for HCl and ascorbic acid, to determine the extent to which the acids dissolve the oxides—the dissolved tin content was measured by ICP-OES. These tests served to verify the reactivity of the tin oxides with the respective acids. The effectiveness and success of the extractions was monitored by the enrichment factors achieved at each step in the process. This was calculated as the ratio of the 117mSn specific activity of the samples (at each time point) and the initial total target yield. The initial total target yields were 0.11±0.02 MBq mmol−1 and 0.10±0.02 MBq mmol−1 for SnO2 and SnO, respectively. Tables 1 and 2 show the trend in the specific activity (MBq mmol−1) achieved at the selected intervals (15, 30 and 60 minutes, 5 and 48 hours), as calculated as the ratio of the measured 117mSn activity (MBq ml−1)—as determined by γ-spectroscopy—and the tin concentration (mmol dm−3)—as measured by ICP-OES. Following the irradiation the 117mSn was dissolved to yield enrichment factors between 2 and 34. Generally speaking, both solutions, HCl and ascorbic acid, were effective in extracting the 117mSn. However, the more reactive tin oxide, SnO, and the stronger acid solution, HCl, respectively, seem to produce higher yields, albeit their specific activities and enrichment factors are lower. As a result SnO2 performed better, while extraction with ascorbic acid proved futile, as observed by the undetectable 117mSn activity in Table 2. An enrichment factor of 34 and 0.07% yield was achieved in the presence of carbon—after treatment with 0.50 mol dm−3 HCl (Table 1). Ultrasonic treatment for 1 hour, after 48 hours and 7 days incubation respectively, had no significant effect on the specific activity, and hence the enrichment factor remained substantially unchanged. As a control, other isotopes were also monitored during this study, namely 113Sn, 113mSn, 125Sn and 125mSn, and their enrichment factors were similar to that of 117mSn. This was to be expected, as they are produced by the same (n, γ) reaction, and especially since the energies of their prompt γ-rays are similar. It is foreseen that the best extraction medium could possibly be a combination of ascorbic acid and HCl, since HCl is better at dissolving the recoil activity, whilst ascorbic acid allows for greater surface area with the recoil capture material whilst simultaneously complexing the 117mSn, keeping it in solution and preventing unwanted hydrolysis and precipitation. Further optimization will be required of the combination and the ideal concentration of each, e.g. by a speciation study using glass electrode potentiometry. Obviously, longer irradiation times will also increase the yields and/or enrichment factors. In another example of the invention, the option to separate and isolate the recoil capture material from the oxides prior to extraction with acid is investigated. The purpose of this is to minimize the presence of “cold” (un-irradiated) tin, which could lower the specific activity and also avoid any irradiated but un-recoiled [117mSn]SnO or [117mSn]SnO2 from being taken up into the acid extract/filtrate, which could produce false positives. One such method involves an initial organic/aqueous liquid-liquid extraction in which the post-irradiated material is added to water and tetrabromoethane (TBE) or toluene, respectively. The choice of the organic solvent depends on the preferred orientation of the organic and aqueous phases. In the separation using TBE and water (first column under each oxide, Table 4), the tin-oxides remain suspended in the top aqueous layer whilst the carbon or graphite is distributed in the organic layer below. The carbon and graphite does not dissolve in the solvents per se, but separation is achieved due to differences in polarity of the recoil capture media and the tin oxides. The 117mSn activity distribution of the organic and aqueous phases, as well the utensils (i.e. glassware and syringes), were measured in a Capintec ionization chamber and yield the results as seen in Table 4. Although meticulous handling was required, fairly good separation was achieved. However, the oxides eventually settled at the aqueous-organic interface, i.e. at the bottom of the aqueous layer on top, which in the event of overshooting during the separation of the phases, became extracted with the TBE phase instead, as seen in the TBE columns of Table 4. When toluene is used instead of TBE, the organic and aqueous phases are inverted, i.e. the toluene layer is on top. In so doing the settling of the tin-oxide at the bottom of the (bottom) aqueous layer, away from the organic phase, makes the extraction more efficient (Toluene column under each oxide, Table 4), effectively minimizing the chance of collecting the oxide with the graphite or carbon. The separation was good and required less handling. Furthermore, there was a lower risk of having the tin oxide present in the organic phase. However, a thin film of toluene had developed around the surface of the water component, which contained some graphite, and was not easily separated. In the tests under this example the recoil activity was not extracted from the recoil capture media, while it merely served as a demonstration of the feasibility of these steps. Water was used in the extractions and not acid or buffer solution so as to avoid premature extraction of the recoil 117mSn ions from the recoil capture media, which then could end up in the aqueous phase. Although the inventors have found the liquid-liquid extraction method to be cumbersome and sensitive to overshooting, refinement of the steps may prove it to be a valid process step. Furthermore, although yields are not significant (2.2% and 2.6% respectively), the objective would be purely to achieve a higher ratio of radioactivity (Bq or Ci) per mass or volume of the product nuclide. The yields can eventually be improved by further experimentation and optimization. In a further example, the phase separation option outlined in Example 2 is extended to include the immobilization with clay of the aqueous phase containing the oxide to allow for the organic layer to be decanted or washed away for further processing and extraction of the recoil 117mSn. In these experiments 5 clays and a conventional household crack filler was considered as solidifying/immobilizing agent, namely: (1) Bentonite-MD/0104/Environment; (2) Ca-Bentonite/Calcium 100#/0106/1-06-10-12-03; (3) Attapulgite; (4) MD-Bentonite/0101; (5) Eccabond-N/Bentonite; and (6) Alcolin interior crack filler (Polyfilla), all obtained from Koppies in the Orange Free State, South Africa (G & W Base & Industrial Minerals, Germiston, 1428, Gauteng, South Africa), and the household crack filler (Polyfilla) obtainable from any local hardware store. These were in turn carefully added to the two extraction mixtures of Example 2 until the aqueous phase was saturated with the respective clay. Approximately 1 g of clay was needed per ml of water. All the clays including the crack filler did not disperse in the organic layers; in the case of toluene they descended straight through unimpeded to eventually react with the water below it. As for TBE, the clays remained dispersed in the upper aqueous layer, with no intrusion into the organic phase. Clays 1, 4 and 5 performed similar throughout, reacting slowly with the water and without settling out in the aqueous layer. Instead, these clays reacted close to the water surface or meniscus. This resulted in some of the unreacted water being trapped below the clay—out of reach of the fresh clay being added. Clays 2 and 3 reacted slower, however they did eventually settle out in the water layer and allowed for good contact and reaction with all the water. The same was observed for the crack filler. Agitating the mixture slightly promoted the settling of the crack filler. Eventually, all the clays swelled up, but not the crack filler. Clays 2 and 3 exhibited the most favourable behaviour and were also the best for use with toluene. The crack filler too behaved well, especially with TBE. However, in the case of the clays, the toluene should be decanted within 15 minutes after introducing the clay, whereas with the crack filler—with either the toluene or TBE—should be allowed to set overnight prior to separation, and even then its hardening is only moderate. In all cases with toluene the clays and crack filler trapped some carbon as it descended through the toluene. To promote sufficient hardening of the crack filler, Na2SO4 was added to it in a 1:1 mass ratio and in so doing the Na2SO4 absorbs any excess water so as to facilitate drying and hardening of the crack filler. However, only a slight improvement was achieved. The inverse approach is also possible, that is, the immobilization or solidification/encapsulation of the recoil capture media using molten paraffin wax, which would replace the organic solvent. However, this would require operating at elevated temperatures so as to avoid inappropriate hardening of the wax. An alternative means of separation could be by dry density separation of the powders in a shaking device. It is envisaged that once the recoil capture material can be successfully separated from the oxides the recoil activity can be isolated or extracted by means of acid leaching, as above, or by combustion of the carbon-based material in oxygen to yield [117mSn]SnO2 or [117mSn]SnO and carbon-dioxide gas. It is believed that the specific methods employed in Examples 1-3 provide a preferred route from a production perspective, as the forms of the target nuclide materials used were resilient and favourable for both harsh radiation conditions and simplicity of post irradiation work-up and isolation. Radiolabelled tin II and IV, i.e. [117mSn]—Sn(II) and [117mSn]—Sn(IV), have been proposed as constituents of prospective radiopharmaceuticals for the palliation of bone pain by RNT. The radionuclide 117mSn emits conversion electrons upon decay and has been reported to have a short range of about 0.2 mm to 0.3 mm in tissue, which renders 117mSn ideal for treatment of bone cancer, as the exposure of sensitive bone marrow to radiation, and hence the radiotoxicity of 117mSn, is limited. Its attractiveness as a radiopharmaceutical is further enhanced by the 159 keV gamma that is emitted in about 86% of decay events, which makes it also an excellent diagnostic imaging radionuclide, e.g. in applications of tumour location. As illustrated by the examples above, when tin is selected as the preferred target nuclide, the oxides SnO and SnO2 are preferred molecular forms of the target nuclide material. The Applicant has found that the oxides of tin are more resistant to radiation damage during extended irradiation times than other compounds of tin. The Applicant has further found that these oxides of tin are generally chemically inert to extraction solvents used in recovering the captured radionuclides post-irradiation. These oxides of tin are also thermally stable with melting points of 1080° C. and 1127° C. respectively, which is particularly advantageous in the reaction conditions to which the oxides are exposed. Similarly to SnO and SnO2, as target nuclide materials, the Applicant has also found that carbon and graphite, as recoil capture materials, are able to endure harsh chemical treatment and are inert in dilute acid. The Applicant has found that recoiled 117mSn atoms/ions are bound loosely to moderately stably to the recoil capture material. This feature, combined with the robustness of carbon and graphite to harsh chemical treatment and inertness in dilute acid, allows for the atoms/ions to be eluted or leached from the recoil capture material by dissolution of the RCM in a dilute acid. Carbon and graphite, as recoil capture materials, are also robust to exposure to larger neutron fluxes and exposure periods, as opposed to C60 fullerenes which can be damaged by epithermal neutrons within 2 hours of irradiation in an unfiltered neutron flux of 1014 cm−2s−1. Graphite is an allotrope of carbon, in which the carbon atoms are covalently bound in flat sheets of fused hexagonal rings. The sheets are loosely stacked and held together by weak Van der Waals forces. Conversely, carbon is amorphous and, unlike graphite, is devoid of a crystalline arrangement of atoms. The inventors do not wish to be bound by theory, but it is expected that the recoiled 117mSn atoms/ions become intercalated within the carbon or graphite lattice, from which they can later be extracted by chemical and/or physical means, for example, by burning of the carbon RCM in oxygen to liberate the enriched [117mSn]tin-oxide with the release of CO2 gas. The Applicant is aware that commercially employed techniques for producing radionuclides known at the time of filing of this application yield 117mSn radionuclides with reported specific activities as high as 25 Ci g−1 (˜88 MBq mmol−1) at end of bombardment (EOB) and are obtainable from suppliers such as Curative Technologies Corporation (CTC). Specific activity of this magnitude can be achieved for example by inelastic neutron scattering irradiation of tin metal enriched to 92% in 117Sn for about 35 days in the high flux SM-3 reactor at the Reactor Institute of Atomic Reactors (RIAR), in Dimitrovgrad, Russia, i.e. by the 117Sn (n, n″) 117mSn reaction. Alternatively, 117mSn can be produced by epithermal neutron irradiation by the hereinbefore described (n, γ) neutron capture reaction, 116Sn (n, γ) 117mSn, but the reaction rate in terms of neutron capture cross section for this reaction (0.14 barns) is generally considered to be too low to produce 117mSn with high specific activity cost effectively by conventional methods. In the abovementioned (n, γ) reactions, however, the resulting nucleus acquires a recoil kinetic energy, as a result of the prompt γ-ray emission upon neutron capture, which is significantly greater than the activation energy achieved by normal thermal reactions (chemical bond energies are typically in the range of 1-5 eV, and the recoil energies acquired by the nucleus due to the recoil is generally well in excess of 10 MeV), while at the same time the atom is chemically transformed, such that the chemical bonding or valence of the recoiled atom is reduced to a lower state, as also described hereinbefore. This allows for chemical extraction based on bonding differentiation. Further, by applying the phenomenon of “recoil implosion”, whereby the recoil radioactive atom is implanted or captured inside an empty fullerene (C60 or C80) cage, carrier-free radio-chemicals can be prepared, for example metallofullerenes such as 177Lu@C60 and 153Sm@C80, where the lutetium-177 (177Lu) and samarium-153 (153Sm) become entrapped within C60- and C80-fullerene cages, respectively. The foregoing is a typical example of a process based on the Szilard-Chalmers principle. Although fullerenes, and for the same reason buckyballs, as empty cage structures are ideal as RCM in the art of the invention, the shortcoming of this route is that such carbon structures are only capable of withstanding the irradiation in a reactor flux of pure thermal neutrons, but are deformed by radiation damage within 2 hours of exposure to epithermal neutrons. In the present invention the use of carbon-based materials such as amorphous carbon and graphite, with no “empty cage” structure, are proposed as recoil capture media to capture the 117mSn recoil atoms from the (n, γ)-reaction with 116Sn, as these carbon-based matrixes are less prone to radiation damage. Thus, the problem of achieving high specific activity recoil 117mSn at relatively low cost and with minimal waste material is specifically addressed. TABLE 1Total tin concentration per extraction sample as measured by ICP OES, the specificactivity of 117mSn for each and the extraction yield, at various incubation times in 0.50 moldm−3 HCl, for targets containing natural SnO2 and SnOTargetTime117mSn ActivityDissolved SnSpec. ActivityEnrichmentmedium(hours)(Bq ml−1)(μmol dm−3)(MBq mmol−1)FactorYield (%)SnO2/0.256.735.111.32180.05Carbon0.56.494.261.53210.0518.63.402.53340.07511.75.112.29310.094811.8 ± 0.96.2 ± 1.31.9 ± 0.417.5 ± 3.90.061_ ± 0.002 7 days 7.4 ± 0.74.5 ± 1.31.7 ± 0.315.6 ± 4.50.038_ ± 0.004 SnO2/0.2510.95.961.83220.08Graphite0.513.56.811.98230.09114.77.661.92230.1 517.47.662.27270.124816.0 ± 2.89.1 ± 1.01.8 ± 0.316.5 ± 1.7 0.09 ± 0.017 days 9.1 ± 2.34.5 ± 1.02.1 ± 0.820 ± 7 0.05 ± 0.01SnO/0.253410208000.16219.55 Carbon0.52500174000.14214.41 12070145000.14211.93 51650113500.1529.51483280 ± 25010100 ± 900 0.33 ± 0.05 3.1 ± 0.415.6 ± 0.37 days 380 ± 1503300 ± 14000.12 ± 0.02 1.11 ± 0.19 1.9 ± 0.9SnO/0.253260194000.17221.95 Graphite0.53010178000.17220.27 12510153000.16216.9 52140130000.17214.41 483870 ± 4708400 ± 28000.50 ± 0.16 4.5 ± 1.816.5 ± 0.37 days2900 ± 35020500 ± 1300 0.14 ± 0.02 1.24 ± 0.0912.4 ± 0.3 TABLE 2Total tin concentration per extraction sample as measured by ICP OES, the specific activityof 117mSn for each, and the extraction yield, at various incubation times in 0.50 mol dm−3 ascorbicacid solution, for targets containing natural SnO2 and SnO. (Where the γ-spectroscopy resultswere below the detection limit (1.8 Bq per gram of sample), the specific activities and enrichmentfactors could not be calculated, as represented by the dash (—) in the table.)Time117mSn ActivityDissolved SnSpec. ActivityEnrichment(hours)(Bq ml−1)(μmol dm−3)(MBq mmol−1)FactorYield (%)SnO2/0.25<1.81.85———Carbon0.5<1.81.58———1<1.81.48———5<1.81.21———483.7 ± 1.33.1 ± 0.31.2 ± 0.611 ± 70.019 ± 0.0107 days3.0 ± 0.72.4 ± 0.41.14 ± 0.1010 ± 40.015 ± 0.008SnO2/0.25<1.81.58———Graphite0.5<1.81.67———1<1.81.67———5<1.81.39———483.9 ± 0.73.1 ± 0.51.27 ± 0.1414 ± 40.03 ± 0.017 days4.1 ± 1.92.72 ± 0.141.54 ± 0.2022.2 ± 0.80.035 ± 0.030SnO/0.25<1.85.38———Carbon0.5<1.86.30———1<1.87.88———54.8232.40.1550.0948580 ± 80 5400 ± 900 0.108 ± 0.0080.99 ± 0.212.6 ± 0.37 days2170 ± 190 20000 ± 900 0.108 ± 0.0051.00 ± 0.219.7 ± 2.5SnO/0.251.8227.60.06610.02Graphite0.52.1921.00.1120.0212.8321.70.1330.0353.0823.60.1330.0348530 ± 4002900 ± 500 0.17 ± 0.111.9 ± 1.22.3 ± 1.27 days1770 ± 90 17400 ± 700 0.102 ± 0.0031.19 ± 0.289 ± 3 TABLE 3Dissolution of SnO2 and SnO in 0.50 mol dm−3 HCl or 0.50 mol dm−3ascorbic acid solutions up to 3 days at ambient temperatureSolutionTimeDissolved SnTin Oxide(0.50 mol dm−3)(hours)(μmol dm−3)SnO2HCl0.253.400.52.5514.2556.81487.663 days16.2SnO2Ascorbic Acid0.252.690.52.5012.3252.32482.133 days2.32SnOHCl0.2583800.52101012070051878048172303 days11060SnOAscorbic Acid0.256.020.59.45113.2517.54819.33 days21.3 TABLE 4Percentages (%) of 117mSn activity present in organic andaqueous phases, following liquid-liquid extraction technique forseparation of tin oxides from the carbon-based recoil capture media,carbon or graphiteLiquidSnOSnO2PhaseTBETolueneTBETolueneAqueous34.197.822.993.9Solvent57.62.250.62.6Glassware8.226.53.5
059057718	abstract	An apparatus for repairing a shroud in which one or more seam welds are cracked. The repair involves the attachment of a splice bracket to the shroud so that the bracket bridges the cracked weld seam and is applicable to both vertical and horizontal weld seams. The bracket is intended to structurally replace the shroud seam weld which is cracked. Multiple splice brackets can be placed along the length of a crack. Each splice bracket is attached to the shroud by a plurality of tapered fastener assemblies. Each tapered fastener assembly includes a first fastener element having a threaded surface and a conical surface coaxial with the threaded surface; a slotted sleeve having an internal surface which matches the conical surface of the first fastener element and an external surface which matches a circular cylindrical surface, and a flange which extends radially outward beyond the external surface; and a second fastener element having a threaded surface threadably engaged with the threaded surface of the first fastener element. The sleeve fits inside aligned holes in the splice bracket and shroud.
051329972	description	DETAILED DESCRIPTION OF THE EMBODIMENTS With reference to FIGS. 1 to 3, an X-ray spectroscopic analyzing apparatus according to a first preferred embodiment of the present invention will be described. Referring first to FIG. 1, the apparatus shown therein comprises a source of X-rays, for example, an X-ray tube 10 having a filament 11 from which electrons e are radiated so as to impinge upon a rotary target 12 which comprises a rotary drum having its outer peripheral surface coated or deposited with a target material. Consequent upon the impingement of the electrons e upon the rotary target 12, an X-ray beam B having an X-ray spectrum peculiar to the target material as shown in FIG. 3 is emitted from the target material forming the rotary target 12. The X-ray beam B emitted from the target material as described above travels towards a shutter means 20 which is, so far used in the illustrated embodiment, supported for movement in a direction generally perpendicular to the path of travel of the X-ray beam B, as shown by the arrow A, and capable of assuming one of intercepting and open positions. The shutter means 20 has a pair of parallel slits 21 and 22 defined therein. This shutter means 20 is operable to intercept completely the passage of the X-ray beam B there-through when in the intercepting position, but to intercept a portion of the X-ray beam B while dividing the remaining portion of the X-ray beam B into two beam components when in the open position. The X-ray beam components B having passed through the slits 21 and 22, respectively, travel towards a total reflection mirror 31 so as to be incident upon first and second reflecting surfaces 31a and 31b of a total reflection mirror 31 at a minute angle of incidence. The total reflection mirror 31 is employed in the form of a prism of a generally trapezoidal shape having the first and second reflecting surfaces 31a and 31b which are substantially opposite to each other, but lie in respective planes inclined so as to converge towards the rotary target 12 and, hence, in a direction confronting the direction in which the X-ray beam components B travel towards the total reflection mirror 31. The total reflection mirror 31 is so designed and so positioned as to have the first and second reflecting surfaces 31a and 31b reflect portions of a spectrum of the X-ray beam B which have respective wavelengths longer than a predetermined wavelength. Those portions of the spectrum of the X-ray beam B reflected by the respective first and second reflecting surfaces 31a and 31b of the total reflection mirror 31 are hereinafter referred to as first and second reflected X-ray components B1 and B2, respectively. On the other hand, of the spectrum of the X-ray beam B coming from the rotary target 12, a beam portion having a wavelength shorter than the predetermined wavelength passes through the total reflection mirror 31 and is subsequently intercepted by a beam stopper 32 which is formed on, or otherwise fitted to, a surface of the total reflection mirror 31 which corresponds in position to the base of the trapezoidal shape of the total reflection mirror or prism 31. It is to be noted that the total reflection mirror 31 and the beam stopper 32 altogether form a filtering means 30 forming an important feature of the present invention. So far illustrated in connection with the embodiment of FIGS. 1 to 3, the filtering means 30 including the total reflection mirror 31 and the beam stopper 32 is disposed on that portion of the optical path extending from the X-ray tube 10 to a sample S to be analyzed, which lies between the X-ray tube 10 and a set of first and second analyzing crystals 41 and 42 as will be described later. The first and second reflected X-ray components B1 and B2 reflected from the first and second reflecting surfaces 31a and 31b of the total reflection mirror 31 subsequently impinge upon the first and second analyzing crystals 41 and 42 at angles .theta.1 and .theta.2 of incidence, respectively. Each of the first and second analyzing crystals 41 and 42 is operable to diffract the associated first or second reflected X-ray component B1 or B2 to provide a first or second diffracted X-ray component B3 or B4 of a wavelength satisfying the following Bragg's formula: EQU 2d.multidot.sin .theta.=n.lambda. wherein d represents an interplanar distance of the crystal; .theta. represents the angle of incidence; .lambda. represents the wavelength of the diffracted X-ray component; and n represents the power of reflection expressed by an integer (i.e., 1, 2, 3, . . . ). In the practice of the present invention, the angle of incidence of the X-ray beam B upon the reflecting surface 31a of the total reflection mirror 31 is chosen to be so small that both of a portion of continuous X-ray beam having a wavelength shorter than the first-order X-ray beam and the X-ray beam having a wavelength longer than the wavelength thereof can be reflected by the surface 31a of the total reflection mirror 31. Similarly, the angle of incidence of the X-ray beam B upon the reflecting surface 31b of the total reflection mirror 31 is chosen to be so large that both of the first-order X-ray beam having a relatively long wavelength and a X-ray beam having a wavelength longer than the wavelength thereof can be reflected by the surface 31b of the total reflection mirror 31. Also, the angle .theta.1 of incidence of the X-ray component B1 upon the first analyzing crystal 41 is so chosen to be of a value effective to diffract a portion of the continuous X-ray including high-order beams to satisfy the Bragg's formula, and similarly, the angle .theta.2 of incidence of the X-ray component B2 upon the second analyzing crystal 42 is so chosen to be of a value effective to diffract the first-order X-ray to satisfy the Bragg's formula. The second analyzing crystal 42 is disposed on a path of travel of the first diffracted X-ray component B3, while the first and second analyzing crystals 41 and 42 are so disposed and so positioned that the first and second diffracted X-ray components B3 and B4 reflected respectively from the first and second analyzing crystals 41 and 42 can travel along the same path towards the sample S to be analyzed. Accordingly, the first diffracted X-ray component B3 can, after having passed through the second analyzing crystal 42, travel towards and subsequently impinges upon the sample S to be analyzed, having passed along the same path as that along which the second diffracted X-ray component B4 reflected from the second analyzing crystal 42 travels and subsequently impinges upon the same sample S to be analyzed. Disposed on the path between the second analyzing crystal 42 and the sample S to be analyzed is an exit slit 50 through which both of the first and second diffracted X-ray components B3 and B4 pass before they reach the sample S to be analyzed. A specific example of the spectroscopic measurement using the apparatus of the present invention will now be described. Assuming that the target material for the rotary target 12 is chosen to be tungsten, the X-ray beam is comprised of the low-order beam such as the WL.beta..sub.1 beam (the first-order X-ray) shown by the solid line in FIG. 3, and the continuous X-ray shown by the broken line in FIG. 3. The reflecting surface 31a of the total reflection mirror 31 shown in FIGS. 1 and 2 serves to cut the X-ray beam B which is a portion of the continuous X-ray having an energy (i.e., a wavelength) greater than 13 keV (.lambda.=0.9536 .ANG.), while the reflecting surface 31b of the total reflection mirror 31 serves to cut the X-ray beam B having an energy (i.e., a wavelength) greater than that of the WL.beta..sub.1 beam (.lambda.=1.2828 .ANG.) which is the first-order X-ray. In this example, the first analyzing crystal 41 is made of a fluorinated lithium (LiF. 2d=4.0273 .ANG., (200) plane serving as a reflecting surface) with the spectral angle 2.theta. set at 27.387.degree. ), and second analyzing crystal 42 is made of graphite (2d=6.708 .ANG., (0002) plane serving as a reflecting surface) with the spectral angle 2.theta. set at 22.032.degree. . Hence, according to the Bragg's formula referred to hereinbefore, the first analyzing crystal 41 is effective to reflect the diffracted X-ray component (.lambda.=0.9536 .ANG.) of 13 keV in energy when the first reflected X-ray component B1 is incident upon the first analyzing crystal 41 and, on the other hand, the second analyzing crystal 42 is effective to reflect the WL.beta..sub.1 beam (.lambda.=1.2828 .ANG.) when the second reflected X-ray component B2 is incident upon the second analyzing crystal 42. Accordingly, even though the target material for the rotary target12 is tungsten, the first diffracted X-ray component B3 of 13 keV which is greater than the energy of the WL.beta..sub.1 beam can be used as the excitation X-rays for radiation onto the sample S to be analyzed and, therefore, even though the sample S to be analyzed contains such elements as tungsten and arsenic having a wavelength at the absorption edge which is shorter than the wavelength of the WL.beta..sub.1 beam, the determination of the presence of such elements in the sample S is possible. Where other elements each having a wavelength at the absorption edge which is longer than the wavelength of the WL.beta..sub.1 beam are desired to be analyzed, the second diffracted X-ray component B4 comprised of the WL.beta..sub.1 beam having a relatively high density can be effectively utilized as the excitation X-rays. Instead of the use of tungsten for the target material, Au may also be employed therefor. In such case, the first and second diffracted X-ray components B3 and B4 may be an AuL.gamma. beam (.lambda.=0.9205 .ANG., E=13.38 keV) and an AuL.alpha. beam (.lambda.=1.2764 .ANG., E=9.73 keV), respectively. Also, in the practice of the present invention, a fluorinated lithium (LiF. 2d=2.848 .ANG., (220) plane serving as a reflecting surface), and a fluorinated lithium (LiF. 2d=4.0273 .ANG., (200) plane serving as a reflecting surface) may be employed as alternative material for the first and second analyzing crystals 41 and 42, respectively. Referring now to FIG. 4, a second preferred embodiment of the present invention will be described. According to this embodiment of the present invention, a shutter means 20A corresponding in function to the shutter means 20 used in the foregoing embodiment is so designed and so positioned that the slits 21 and 22 can be alternately brought into alignment with the path of travel of the X-ray beam B. In other words, the slits 21 and 22 of the shutter means 20A are alternately closed and opened, respectively. Thus, it will readily be understood that the first and second diffracted X-ray components B3 and B4 are alternately impinged upon the sample S to be analyzed. Except for the difference lying in the design of the shutter means, the apparatus according to the second preferred embodiment of the present invention is similar to and function in a manner substantially similar to that according to the foregoing embodiment and, therefore, the details thereof will not be reiterated for the sake of brevity. The X-ray spectroscopic analyzing apparatus constructed according to the second preferred embodiment of the present invention can be advantageously employed in the practice of a total reflection fluorescent X-ray analysis which will now be described with reference to FIGS. 5 to 12. Referring first to FIG. 5, the sample S to be analyzed is employed in the form of a semiconductor wafer made of silicon and containing impurities such as arsenic injected thereinto. The sample S has a sample surface Ss adapted to be radiated by the first and second diffracted X-ray components B3 and B4 having travelled along the single and same path. Each of the first and second diffracted X-ray components B3 and B4 is in the form of a monochromatic beam of light having a wavelength shorter than the absorption edge wavelength of an element to be determined, for example, arsenic, which is contained in the sample S. By way of example, tungsten may be employed for the target material of the rotary target 12, and the second diffracted X-ray component B4 may be chosen the WL.beta..sub.1 beam of a kind having a wavelength .lambda.2 somewhat shorter than the absorption edge wavelength thereof while the first diffracted X-ray component B3 may be chosen the 13 keV beam having a wavelength .lambda.1 shorter than the wavelength .lambda.2, for example, 1/2 to 1/3 of the absorption edge wavelength thereof. So far shown in FIG. 5, the sample S to be analyzed is placed on a sample bench 51 adapted to be driven by a drive unit 52 so as to tilt through a minute angle about the point P of incidence of the diffracted X-ray components B3 and B4 on the sample surface Ss of the sample S to be analyzed. While the angle of incidence identified by .alpha. defined between the sample surface Ss and the direction of incidence of the diffracted X-ray components B3 and B4 is adjustable with a tilting motion of the sample bench 51, the angle .alpha. of incidence is selected to be within the range of 0.01 to 0.2 degree so that the total reflection can take place from the sample surface Ss of the sample S to be analyzed. The determination of the element contained in the sample S is carried out in the following manner. At the outset, only the first slit 21 of the shutter means 20A shown in FIG. 4 is brought into alignment with the path of travel of the X-ray beam B reflected from the rotary target 12 so that, as shown in FIG. 7(a), the first diffracted X-ray component B3 can impinge upon the sample surface Ss at a specific angle .alpha.1 of incidence. Then, a portion of the first diffracted X-ray component B3 which has been impinged upon the sample surface Ss undergoes the total reflection therefrom thereby to provide a reflected X-ray component B5, while the remaining portion of the first diffracted X-ray component B3 impinging upon the sample surface Ss excites an element present in a surface region (of a depth ranging from 10 to 20 .ANG.) of the sample surface Ss. When the element in the surface region of the sample surface Ss is so excited, the element emits a first fluorescent X-ray component B6 of a wavelength peculiar to such element. The first fluorescent X-ray component B6 emitted from the element in the sample S travels towards a fluorescent X-ray detector 60 by which the intensity I of the X-ray component can be detected. Thereafter, only the second slit 22 of the shutter means 20A is brought into alignment with the path of travel of the X-ray beam B reflected from the rotary target 12 so that, as shown in FIG. 7(b), the second diffracted X-ray component B4 can impinge upon the sample surface Ss at the same angle .alpha.1 of incidence. Then, in a manner similar to the first diffracted X-ray component B3 described hereinabove, a portion of the second diffracted X-ray component B4 which has been impinged upon the sample surface Ss undergoes the total reflection therefrom thereby to provide a reflected X-ray component B8, while the remaining portion of the second diffracted X-ray component B4 impinging upon the sample surface Ss excites an element present in the surface region of the sample surface Ss. When the element in the surface region of the sample surface Ss is so excited, the element emits a second fluorescent X-ray component B7 of a wavelength peculiar to such element. Thus, the second fluorescent X-ray component B7 emitted from the sample S is subsequently detected by the fluorescent X-ray detector 60 to determine the intensity I of the X-ray component. Thereafter, the sample S is somewhat tilted by driving the sample bench 51 shown in FIG. 5 so that the angle .alpha.2 of incidence can have a value greater than the angle .alpha.1 of incidence shown in FIG. 7(a). With the sample surface Ss held at the angle .alpha.2 of incidence, procedures similar to those shown in and described with reference to FIGS. 7(a) and 7(b) are repeated. Specifically, the sample surface Ss is again radiated by the first diffracted X-ray component B3 in a manner similar to that described with reference to FIG. 7(a). However, since the angle .alpha.2 of incidence is greater than the angle .alpha.1 of incidence, the first diffracted X-ray component B3 penetrates deep into the surface region of the sample S as shown in FIG. 7(c) and, when an element present in a deeper portion of the sample S is consequently excited by such first diffracted X-ray component B3, a first fluorescent X-ray component B6 is subsequently emitted from such deeper portion of the sample S. The first fluorescent X-ray component B6 is subsequently detected by the fluorescent X-ray detector 60 to determine the intensity I of the X-ray component. Similarly, the second diffracted X-ray component B4 is impinged upon the sample surface Ss, as shown in FIG. 7(d), in a manner similar to that described with reference to FIG. 7(b). By a similar reason as described with reference to FIG. 7(b), that portion of the second diffracted X-ray component B4 which has been impinged upon the sample surface Ss undergoes the total reflection therefrom thereby to provide a reflected X-ray component B8, while the remaining portion of the second diffracted X-ray component B4 impinging upon the sample surface Ss excites an element present in the surface region of the sample surface Ss. When the element in the surface region of the sample surface Ss is so excited, as shown in FIG. 7(d), the element emits a second fluorescent X-ray component B7 of a wavelength peculiar to such element which is subsequently detected by the fluorescent X-ray detector 60 to determine the intensity I of the X-ray component. Thus, as hereinbefore described, using the different angles .alpha. of incidence, that is, by stepwisely varying the angle .alpha. of incidence, the radiation of the first and second diffracted X-ray components B3 and B4 to the sample surface Ss and the detection of the first and second fluorescent X-ray components B6 and B7 are repeated to determine the intensity I of the fluorescent X-ray component emitted from the element in the sample S at the different angle .alpha. of incidence of any one of the first and second diffracted X-ray components B3 and B4. As shown in FIG. 8, the intensity I of the fluorescent X-ray component varies with a change in angle .alpha. of incidence of the first diffracted X-ray component B3 upon the sample surface Ss as shown by the solid line, while the intensity I of the fluorescent X-ray component varies with a change in angle .alpha. of incidence of the second diffracted X-ray component B4, as shown by the dotted line. The fluorescent X-ray detector 60 outputs measurements descriptive of the intensity I of the fluorescent X-ray component which varies with a change in angle .alpha. of incidence of any one of the first and second diffracted X-ray components B3 and B4 upon the sample surface Ss. The measurements outputted from the fluorescent X-ray detector 60 are processed by a multi-pulse height analyzer 61 in the following manner. The relationship between the angle .alpha. of incidence of each of the first and second diffracted X-ray components B3 and B4 and the depth h of the surface region of the sample S into which the diffracted X-ray component B3 or B4 penetrates is such as shown in FIG. 9 and is generally fixed depending on the wavelength .lambda. of the associated diffracted X-ray component B3 or B4 impinging upon the sample surface Ss. Accordingly, with this relationship determined beforehand, and from a result of detection (data outputted from the fluorescent X-ray detector 60) which is descriptive of the relationship between the angle .alpha. of incidence and the intensity I of the fluorescent X-ray components as shown in FIG. 8, the intensity I of the X-ray component emitted from a varying depth h of the sample S for each of the wavelength .lambda.1 of the X-ray component B3 and the wavelength .lambda.2 of the X-ray component B4 can be determined as shown in FIG. 10. The relationship between the intensity I of the fluorescent X-ray component and the density C of the element to be analyzed is fixed for each of the wavelengths .lambda.1 and .lambda.2 as shown in FIG. 11 and, therefore, this relationship has to be empirically determined using testpieces. From the relationship between the intensity I of the fluorescent X-ray component and the density C shown in FIG. 11 and the relationship between the depth h of the sample S and the intensity I of the fluorescent X-ray component as shown in FIG. 10, the density C of the element at the specific depth h of the sample S can be determined for each of the wavelengths .lambda.1 and .lambda.2. A pattern of distribution of the densities so determined for the respective wavelengths .lambda.1 and .lambda.2 involves an measurement error depending on preset values of various parameters used during the analysis performed by the multi-pulse height analyzer 61 and, therefore, an averaged value of those densities is used as a distribution of the density of the element to be analyzed. In this way, even though the analysis involves the measurement error as a result of the use of the diffracted X-ray components B3 and B4 each being used in the form of the monochromatic beam of light, this measurement error can be advantageously averaged to minimize the measurement error. Hence, with the system hereinabove described according to the present invention, the reliability of the elemental analysis can be improved. Thus, from the foregoing description of the present invention, the first and second analyzing crystals are effective to provide the excitation X-ray of a wavelength shorter than the low-order beam and the excitation X-ray comprised of a low-order beam having a relatively high density, respectively. Therefore, the spectroscopic determination of an element having an absorption edge wavelength, which is not only longer than, but also shorter than the wavelength of the low-order beam of a relatively high density, can be accomplished. According to another aspect of the present invention, the use of the shutter mean for selectively causing one of the first and second diffracted X-ray components to be incident upon the surface of the sample to be analyzed makes it possible to allow the first and second diffracted X-ray components from the respective first and second analyzing crystals to be alternately incident upon the surface of the sample at a preselected minute angle of incidence so that the use of the total reflection fluorescent X-ray analyzing technique can result in an improved and precise spectroscopic measurement. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings which are used only for the purpose of illustration, those skilled in the art will readily conceive numerous changes and modifications within the framework of obviousness upon the reading of the specification herein presented of the present invention. For example, although in describing any one of the foregoing embodiments of the present invention reference has been made to the use of two diffracted X-ray components B3 and B4, three or more diffracted X-ray components may be equally employed in the practice of the present invention. Also, the filtering means 30 used in any one of the first and second preferred embodiments of the present invention has been described as positioned on the optical path between the X-ray tube 10 and the first and second analyzing crystals 41 and 42. However, in the practice of the present invention, it may be positioned at a location between the second analyzing crystal 42 and the sample S. Accordingly, such changes and modifications are, unless they depart from the spirit and scope of the present invention as delivered from the claims annexed hereto, to be construed as included therein.
	claims	1. A method of recovering uranium (U) using a process for treating a washing wastewater comprising hydrogen peroxide (H2O2), sodium carbonate (Na2CO3), and a uranium complex, the washing wastewater released during a washing process of a uranium hexafluoride (UF6) cylinder, the method comprising:(1) adding sodium hydroxide (NaOH) to the washing wastewater to precipitate the uranium complex, contained in the washing wastewater, in a sodium diuranate (NaDU) form;(2) separating a sodium diuranate (NaDU) precipitate formed during the step (1) and the washing wastewater using filtration;(3) evaporating the washing wastewater filtered during the step (2); and(4) cooling a vapor generated during the step (3) to recover a condensate and then checking remaining amounts of uranium (U) and fluorine (F). 2. The method of claim 1, wherein a demineralized water or a mixed solution, including the hydrogen peroxide (H2O2) and the sodium carbonate-(Na2CO3), is used as a washing solution during the washing process of the uranium hexafluoride (UF6) cylinder, causing generation of the washing wastewater. 3. The method of claim 1, further comprising:after the step (3),(5) filtering and evaporating a remaining wastewater after the evaporating of the step (3); and(6) cooling a vapor generated during the step (5) to recover a condensate and then checking remaining amounts of uranium (U) and fluorine (F). 4. The method of claim 1, wherein a sodium hydroxide (NaOH) aqueous solution is added while the washing wastewater is heated during the step (1) so that a pH is controlled to form a sodium diuranate (NaDU) solid, thereby performing precipitation. 5. The method of claim 1, wherein during the step (3), a steam is supplied to evaporate water, the evaporated water is transported through a heat exchanger to a condensate storage tank, and a residue is returned to the step (2).
048903124	claims	1. A piezoelectric attenuation assembly for slit radiography, which comprises: a carrier assembly having openings defining a passageway for a planar X-ray beam of a predetermined width and height; a piezoelectric plate member positioned within and mounted at a base portion thereof to said carrier assembly and having a free end portion extending towards said passageway, said piezoelectric plate member formed of a single plate of piezoelectric material with a plurality of elongated attenuation elements beginning at and extending from said base portion to said free end portion. 2. The piezoelectric attenuation assembly as defined in claim 1 wherein each of said elongated attenuation elements are trapezoidally-shaped and defined by a slit formed between adjacent elongated attenuation members. 3. The piezoelectric attenuation assembly as defined in claims 1 or 2 wherein said piezoelectric plate member is formed with grooves in said base portion coincident with said slits and of a thickness of about one-half of a thickness of said piezoelectric plate member. 4. The piezoelectric attenuation assembly as defined in claim 3 and further including a reinforcing member mounted to said base portion of said piezoelectric plate member on a side thereof opposite said grooves. 5. The piezoelectric attenuation assembly as defined in claims 1 or 2 wherein said free ends of said elongated attenuation members are provided with X-ray radiation absorption material. 6. The piezoelectric attenuation assembly as defined in claim 5 wherein a center elongated attenuation member of said piezoelectric plate member is provided with X-ray radiation absorption material extending forward of adjacent elongated attenuation elements. 7. The piezoelectric attenuation member as defined in claim 6 wherein said center elongated attenuation element includes projections of said X-ray radiation absorption material extending forward of adjacent elongated attenuation elements and covering openings between said center elongated element and adjacent elongated attenuation elements. 8. The piezoelectric attenuation assembly as defined in claim 3 wherein said base portion of said piezoelectric plate member including said grooves is disposed away from said passageway and further including conductor means for each of said elongated attenuation elements via respective areas thereof between said grooves and a conductor member connected to a side of said piezoelectric plate member opposite said grooves. 9. The piezoelectric attenuation assembly as defined in claim 1 and further including means disposed in said carrier assembly for limiting the dimensions of said passageway for said planar X-ray beam. 10. The piezoelectric attenuation assembly as defined in claim 9 wherein said limiting means includes X-ray radiation absorption material positioned on either side of said piezoelectric plate member to permit adjustment to said width of said planar X-ray beam. 11. The piezoelectric attentuation assembly as defined in claim 9 wherein said limiting means includes X-ray radiation absorption material position parallel to said piezoelectric plate member to permit adjustment to said height of said planar X-ray beam. 12. The piezoelectric attenuation assembly as defined in claim 1 wherein said free end portion of said piezoelectric plate member is formed of circular shape and wherein said elongated piezoelectric elements are of equal length radially extending towards said base portion thereof. 13. The piezoelectric attenuation assembly as defined in claim 1 wherein free ends of said elongated attenuation elements are formed in wedge-shaped configuration. 14. The piezoelectric attenuatin assembly as defined in claim 13 wherein said wedge-shaped free ends of said elongated attenuation elements include X-ray radiation absorption material. 15. A piezoelectric member for slit radiography, which comprises: a piezoelectric plate member of a single plate of piezoelectric material having a base portion and a plurality of elongated attenuation elements beginning at and extending from said base portion. 16. The piezoelectric member as defined in claim 15 wherein each of said elongated attenuation elements are trapezoidally-shaped and defined by a slit formed between adjacent elongated attenuation members. 17. The piezoelectric member as defined in claims 15 or 16 wherein said piezoelectric plate member is formed with grooves in said base portion coincident with said slits and of a thickness of about one-half of a thickness of said piezoelectric plate member.
052389758	abstract	A microwave radiation absorbing adhesive comprises dissipative particles bound in a thermoplastic or thermosetting adhesive The absorbing adhesive may be applied directly to the surface of any object, or to an irregularly shaped object, or into cracks or crevices in or between objects, including conventional absorbers. Several types of dissipative particles and adhesives may be used.
	description	The present application claims priority from Japanese Patent application serial no. 2008-205061, filed on Aug. 8, 2008, the content of which is hereby incorporated by reference into this application. The present invention relates to a core of a light water reactor and a fuel assembly, and more particularly, to a core of a light water reactor and a fuel assembly suitable for a boiling water reactor. When actinide nuclide, which has many isotopes and is included in a nuclear fuel material in a fuel assembly loaded in a core of a light water reactor, burns in a core, the actinide nuclide to transfers among isotopes in succession by nuclear transmutation such as nuclear fission and neutron absorption. Since odd-numbered nucleus that has a large nuclear fission cross section with respect to a resonance and thermal neutrons, and even-numbered nucleus that undergoes fission only for fast neutrons are present as the actinide nuclide, in general, present ratios of the isotopes present in the actinide nuclides included in the fuel assembly largely change as the actinide nuclides burn. It is known that this present ratio change depends on the neutron energy spectrum at the position at which the fuel assembly is loaded in the core. Current light water rectors use slightly enriched uranium as nuclear fuel. However, since the natural uranium resource is finite, it is necessary to successively replace fuel assemblies used in the light water reactor with recycled fuel assemblies including a nuclear fuel material which is formed by enriching depleted uranium, which is a residual after uranium enrichment, with the transuranic nuclide (hereinafter referred to as TRU) extracted from spent fuel assemblies in the light water reactor. TRU needs to be recycled as a useful resource over a very long period predicted to be necessary for commercial reactors, and during this period, the amount of TRU needs to always increase or to be maintained nearly constant. JP 3428150 B describes technology to implement a breeder reactor in which the amount of fissionable Pu is increased or maintained nearly constant in light water reactors that occupy most of the current commercial reactors. In a light water reactor in which the breeder reactor described in JP 3428150 B and R. TAKEDA et al., Proc. of International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems. GLOBAL '95 Versailles, France, September, 1995, P. 938 is became a reality, a plurality of fuel assemblies, each of which has a hexagonal transverse cross section, are disposed in the core, each fuel assembly being formed by closely arranging a plurality of fuel rods in a triangular grid. In the core of this light water reactor, the amount of water around the fuel rods is lessened due to the close arrangement of the fuel rods, and thereby the ratios of resonant energy neutrons and fast energy neutrons are increased. In addition, the height of a mixed oxide fuel section of the TRU is reduced and blanket zones loaded with depleted uranium are disposed above and below the mixed oxide burning part so as to maintain a negative void coefficient, which is a safety criterion. The core is formed in two stacked stages by applying the concept of a parfait-type core described in G. A. Ducat et al., Evaluation of the Parfait Blanket Concept for Fast Breeder Reactors, MITNE-157, January, 1974, thereby a breeding ratio of 1 or more is ensure, keeping the economy. To recycle TRU, the reprocessing of spent fuel is indispensable. Due to a fear that consumer TRU is diverted to weapons of mass destruction, there has been an increasing demand for nuclear non-proliferation and thereby restrictions on TRU recycling have been severe. It is certain that an electric power generating system superior to a fission reactor is put into practical use on some day in the future. At that time, the value of TRU is lowered from a very useful fuel equivalent to enriched uranium to a cumbersome long-lived waste material. Accordingly, the most important object in nuclear power development is to establish a TRU disposal method. R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725 suggests a TRU disappearance reactor and a light water breeder reactor for recycling TRU while the present ratio of each isotope of the TRU is maintained nearly constant to achieve multiple recycling, in which recycling, the TRU obtained by reprocessing a spent nuclear fuel is reused as a new nuclear fuel to repeat recycling. This light water breeder reactor can recycle in a state in which the amount of TRU is maintained constant or increased, and it has a core loaded with fuel assemblies with a high burnup and high nuclear proliferation resistance. The TRU disappearance reactor is a reactor for reducing TRU through nuclear fission by successively reducing and aggregating the TRU until all the TRU is reduced by undergoing fission to the amount of the TRU being loaded in the last one core to prevent the TRU from becoming a long-life radioactive waste at the end of the light water reactor's purpose. A light water reactor for recycling TRU was achieved in R. TAKEDA et al., Proc. of International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems. GLOBAL '95 Versailles, France, September, 1995, P. 938; such that a recycle reactor effectively uses a seed fuel, in which the amount of TRU is maintained constant, with a sufficient safety margin to meet design standards for abnormal transience and accidents; and that the recycle reactor can stabilize supply of energy for a long period of time by burning all depleted uranium, and by making all the TRU undergo fission, the recycle reactor prevents the TRU from becoming a long-life radioactive waste at the end of the nuclear fission reactor's purpose when the TRU has become no longer necessary. On the other hand, there has recently been a movement to tighten up the attitude toward safety; consequently, a core having a high safety potential is expected, having a sufficient safety margin for responding to an accident outside the design standards (Anticipated Transient Without Scram, or ATWS) such as, for example, a compound event where the core flow rate suddenly drops for some reason and all control rods cannot be inserted into the core. An object of the present invention is to provide a core of a light water reactor and a fuel assembly which can further increases a safety margin without sacrificing an economic efficiency of the light water reactor. The present invention for attaining the above object is characterized in that, in a fuel assembly, which was loaded in a core, with a burnup of 0, a ratio of Pu-239 in all transuranium nuclides included in the fuel assembly is in a range of 40 to 60%, sum of heights of a lower blanket zone and an upper blanket zone formed in the core is in a range of 250 to 600 mm, and the height of the lower blanket zone is in a range of 1.6 to 12 times the height of the upper blanket zone. According to the present invention, a safety margin can be sufficiently maintained even with the occurrence of a compound event, in which core flow rate is suddenly dropped for some reason and all control rods cannot be inserted into the core at the same time during the operation of the light water reactor, beyond design standards. When such a compound event occurs, void fraction in the core rapidly increases, a boiling start point of coolant being slightly sub-cooled, being supplied into the core from below the core, shifts toward a lower end of the core, and the power distribution in the axial direction of the core also shifts toward the lower end of the core. Therefore, excess neutrons are shifted toward the lower end of the core. These shifted excess neutrons can be absorbed by neutron absorber in a neutron absorber filling-zone, an upper end of which is positioned in the vicinity of the lower end of the core, of a safety rod. As a result, power of the light water reactor can be automatically reduced to the power at which the fuel assemblies in the core can be cooled by the capacity of the coolant suppliable from an emergency high-pressure core flooder. Thus, a sufficient safety potential can be maintained upon the occurrence of a compound event beyond the design standards. In this way, the present invention can improve the safety margin without sacrificing the economic efficiency of the light water reactor even with the occurrence of the compound event. The above object can also be achieved when, in a fuel assembly, which was loaded in a core, with a burnup of 0, a ratio of Pu-239 in all transuranium nuclides included in the fuel assembly is at least 5% but less than 40%, a height of an upper blanket zone is in a range of 20 to 100 mm, and a lower end of a fissile zone matches a lower end of the core. According to the present invention, a safety margin can be further increased without sacrificing an economic efficiency of a light water reactor. Cooling water (coolant) for cooling fuel assemblies in a core of a BWR is supplied into a core from below as sub-cooled water at approximately 10° C., and as cooling the fuel assemblies, it becomes a two-phase flow including saturated water and steam-and-water. This cooling water becomes a two-phase flow with a void volume fraction of approximately 60 to 80% at an outlet of the core. Thus, a distribution of hydrogen atoms, which significantly contribute to moderate neutrons, in the axial direction of the core decreases from the lower portion toward the upper portion of the core. For this reason, if the fuel assemblies having one zone of axial enrichment distribution are loaded into the core of the BWR, a large power peak is formed in the lower region of the core. When the flow rate of the cooling water in the core is reduced for some reason, the boiling start point of the cooling water is shifted further downward than that of when the reactor is operated at its rated power and rated core flow rate, and the power peak is shifted further downward in the core as well. The inventors have thoroughly considered the above characteristics of a core of a BWR and found out that, in a core of a light water reactor loaded with a plurality of fuel assemblies including nuclear fuel material obtained by reprocessing, the ratio of Pu-239 in all TRU included in fuel assemblies at the time of zero burnup is in a range of 40 to 60%, when an upper end of a neutron absorber filling-zone of a control rod is disposed in the vicinity of a lower end of the core, a safety margin can be further increased without sacrificing the economic efficiency of the light water reactor by applying any of the following constitutions, i.e., (1) making the sum of the heights of an upper blanket zone and a lower blanket zone in the core in a range of 250 to 600 mm and at the same time, making the height of the lower blanket zone in a range of 1.6 to 12 times that of the upper blanket zone, (2) making the height of the lower blanket zone higher than that of the upper blanket zone and at the same time, making the height of the upper blanket zone in a range of 30 to 105 mm, and (3) making the height of the lower blanket zone higher than that of the upper blanket zone and at the same time, making the height of an upper fissile zone including Pu for the core higher than the height of a lower fissile zone including Pu within a range of 10 to 25 mm. In other words, by applying any of the constitutions (1), (2), and (3), even with the occurrence of a compound event, which is beyond design standards, such as the coolant in the core is lost for some reason and all the control rods cannot be into the core for some reason, excess neutrons in the core are automatically absorbed by the neutron absorber disposed in the lower end of the core, because a void fraction in the core is rapidly increased when the flow rate of the coolant supplied to the core (a core flow rate) is suddenly decreased, and the power distribution in the axial direction of the core is shifted toward the lower end of the core. For this reason, reactor power is automatically reduced to the reactor power at which cooling can be achieved by the flow rate of the coolant supplied to the core by an emergency high-pressure core flooder that is automatically activated in the case of an emergency. As described above, the inventors have newly found out that a safety potential in a core of a light water reactor can be enhanced by applying any of the constitutions (1), (2), and (3). In addition, the inventors have found out that the safety margin can also be increased, as done in above, by (4) making the height of the lower blanket zone higher than that of the upper blanket zone and at the same time, disposing neutron absorbing material to the position where excess neutrons generated at the time of the accident gather. The safety margin can be further improved by combining some of the constitutions (1), (2), (3), and (4). For example, when the constitutions (1) and (2) are combined, the safety margin will be larger than that of the constitution (1) alone; and when the constitution (3) is additionally combined to the combination of the constitutions (1) and (2), the safety margin will be further improved than that of the constitutions (1) and (2) combined. This can be said to the other combinations in which the constitution (2), (3), or (4) is combined to other two constitutions. When (4) is additionally combined to the combination of the constitutions (1), (2), and (3), the safety margin will be the largest among the combinations including some of the constitutions (1) to (4). Furthermore, the inventors have newly found out that, in a core of a light water reactor loaded with a plurality of fuel assemblies including nuclear fuel material obtained by reprocessing, the ratio of Pu-239 in all TRU included in fuel assemblies at the time of zero burnup is at least 5% but less than 40%, when the upper end of a neutron absorber filling-zone of a control rod is disposed in the vicinity of the lower end of the core, a safety margin can be further increased without sacrificing economic efficiency and design target performance of TRU multi-recycling by applying any of the following constitutions, i.e., (5) matching a lower end of a fissile zone in the core to the lower end of the core and at the same time, making the height of an upper blanket zone in a range of 20 to 100 mm, and (6) having the upper blanket zone and at the same time, making a height of an upper fissile zone in the core higher than a height of a lower fissile zone within a range of 10 to 25 mm. The safety margin is further improved by combining the constitution (6) to the constitution (5) compared to the light water reactor core having either constitution (5) or (6) alone. A goal of the present invention is to improve safety of a recycling-type light water reactor which utilizes nuclear fuel material containing TRU obtained by reprocessing. Such present invention is made to maintain safety even with the occurrence of multiple accidents beyond design standards and to allow TRU multi-recycling to continue, when the performance as a breeder reactor (a light water breeder reactor) is to be improved in the light water reactor shown in JP 3428150 B, and when the TRU considered to be disposed of as a long-life radioactive waste when it is no longer necessary, is to be utilized as nuclear fuel material until all the TRU, except for those being loaded in the last one core, are made to undergo fission. A reactor core of a light water reactor having improved performance as a breeder reactor is described. For example, a light water breeder reactor that yields a fissile Pu residual rate of 1 or more in a BWR was first achieved in JP 3428150 B. To realize the breeder reactor in a light water reactor, neutron energy in the core must be maintained at a high level. However, since the mass of a hydrogen atom forming the water used as a coolant in the light water reactor is small compared to that of Na generally used as a coolant in a breeder reactor, the energy loss of neutrons at one collision becomes large in the light water reactor. Thus, it is necessary to reduce a ratio of coolant per unit volume of nuclear fuel material in the light water reactor. When a nuclear fuel material having a ratio of Pu-239 in all TRU in a range of more than 60% is recycled, the following problems may arise, i.e., (a) a capacity for cooling the nuclear fuel material in the core is not enough, (b) a burnup of the fuel assemblies is reduced, impairing the economic efficiency of the fuel, and (c) a gap between fuel rods disposed in the fuel assembly become too narrow, causing the production of the fuel assembly to be difficult. When a nuclear fuel material having a ratio of Pu-239 in all TRU in a range of less than 40% is recycled, the following problems may arise, i.e., (d) a ratio of odd-numbered nuclides having a larger nuclear fission cross section is reduced compared to that of even-numbered nuclides having a smaller nuclear fission cross section, causing a fissile Pu residual rate of 1 or more to be difficult to attain, and (e) the core becomes large and the void coefficient, which is a safety indicator, is worsened. Therefore, in a light water breeder reactor, the ratio of Pu-239 contained in all the TRU should be within a range of 40 to 60%. Next described is a reactor core of a light water reactor (a TRU disappearance reactor) which allows the TRU being considered to be disposed of as a long-life radioactive waste when it is no longer necessary, to be utilized as nuclear fuel material until all the TRU except for those being loaded in the last one core is made to undergo fission. The inventors have thought out to reduce the TRU by nuclear fission when the TRU is no longer needed, by integrating the TRU dispersed in many cores based on the amount of reduction of TRU, and leaving the TRU only in one core at the end. At this time, when a nuclear fuel material having a ratio of Pu-239 in all the TRU in a range of at least 40% is recycled to prevent the TRU from becoming a long-life radioactive waste, it takes too long to integrate the TRU in one core since the speed of the TRU reduction is slow. When a nuclear fuel material having a ratio of Pu-239 in all the TRU in a range of less than 5% is used for recycling, the core becomes large and the void coefficient is worsened. Therefore, in a TRU disappearance reactor, the ratio of Pu-239 contained in all the TRU should be set to a range of at least 5% but less than 40%. Now, an overview of a parfait-type reactor core is described. The parfait-type reactor core uses a fuel assembly having a lower blanket zone, a lower fissile zone, an inner blanket zone, an upper fissile zone, and an upper blanket zone disposed in this order from the lower end portion to the upper end portion, as a new fuel assembly (having a burnup of 0) for loading. In the parfait-type reactor core, a lower blanket zone, a lower fissile zone, an inner blanket zone, an upper fissile zone, and an upper blanket zone are formed from the lower end portion to the upper end portion as well. The lower and upper fissile zones include TRU oxide fuel (or mixed oxide fuel of TRU oxide and uranium oxide). The present invention is intended for the above recycling-type light water reactor and the light water reactor core. The results of study done by the inventors are described below. First of all, the results of the study by the inventors regarding a core of a light water breeder reactor are described below. In the description, a BWR core with an electric power of 1350 MW and a breeding ratio of 1.01, loaded with 720 fuel assemblies, each of which having 271 fuel rods, in the core is used as an example of the core of the light water breeder reactor. While the cores disclosed in JP 3428150 B; R. TAKEDA et al., Proc. of International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems. GLOBAL '95 Versailles, France, September, 1995, P. 938; and R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725 can safely and sufficiently respond to abnormal transience and accidents within design standards, this BWR core cannot always respond in a sufficient manner upon the occurrence of a compound event such as the core flow rate being suddenly decreased for some reason and in addition, all control rods being inoperable, when such an event is currently regarded as beyond the design standards. In some cases, TRU recycling may have to be stopped in the middle. In other words, multiple recycling may not be continued. In order to continue TRU recycling while maintaining a sufficient safety potential in the above BWR core, the void coefficient must be maintained within a predetermined range. The inventors have studied a method to improve a safety margin for the core of the light water reactor which has the lower and upper blanket zones, is loaded with a plurality of fuel assemblies including nuclear fuel material obtained by reprocessing. In each of these fuel assemblies, the ratio of Pu-239 in all TRU included in the fuel assembly at the time of zero burnup is in a range of 40 to 60%. As a result of the study, the inventors have newly found out a way to realize TRU multi-recycling such that, when the core flow rate is suddenly dropped for some reason specific to the function of the BWR, the void fraction in the core rapidly rises and the boiling start point of the coolant being slightly sub-cooled and flowing into the core from below, shifts to the lower end side of the core, which makes the power distribution in the axial direction of the core shift to the lower end side of the core; thus, by disposing neutron absorbing material in the vicinity of the lower end of the core, a sufficient safety potential can be maintained upon the occurrence of multiple accidents. Based on this knowledge, the inventors have newly found out that the safety potential can be enhanced while the breeding ratio of the TRU is maintained by adapting any of the above (1), (2), (3), and (4). In the core of the light water reactor discussed here, the control rods are inserted into the core from below. In FIG. 1, a property 1 shows an average power distribution in the axial direction of the core in the core having a fissile Pu breeding rate of 1.01 during its rated power operation, and a property 2 shows an average power distribution in the axial direction of the core when the core flow rate is reduced to 4 kt/h which is a flow rate of the coolant from an emergency high-pressure core flooder. In FIG. 2, a property 3 shows an average void fraction distribution in the axial direction of the core corresponding to the property 1, and a property 4 shows an average void fraction distribution in the axial direction of the core corresponding to the property 2. Due to the sudden drop of the core flow rate from a rated value of 21 kt/h to 4 kt/h, the void fraction distribution rapidly rises from the property 3 to the property 4, and at the same time, the boiling start point shifts to the lower end side of the core. This also shifts the power distribution in the axial direction of the core to the lower end side of the core from the property 1 to the property 2, as can be seen. When the core flow rate drops in such an extreme way, a large power peak may be generated in a reflector (cooling water) in the lower portion of the core, and positive reactivity may be introduced into the core in some cases. In the reactor cores disclosed in JP 3428150 B; R. TAKEDA et al., Proc. of International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems. GLOBAL '95 Versailles, France, September, 1995, P. 938; and R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725, each safety rod, which is one type of control rod being withdrawn from the core during the rated power operation, is held, while being withdrawn, at the position which does not affect the core by introducing negative reactivity (a position 20 to 30 cm below the lower end of the core) as usually done in a relatively low-height core having a height of 2 m or less. Thermal neutron flux distribution in the axial direction of the core in this state is shown as a property 5 in FIG. 3. Thus, an upper end of a neutron absorber filling-zone of the safety rod being withdrawn below the lower end of the core during the reactor operation as described above, is positioned at the lower end of the core, so that this safety rod can absorb excess neutrons shifting to the lower portion of the core when the core flow rate is suddenly decreased. The thermal neutron flux distribution in the axial direction of the core at this time is shown as a property 6 in FIG. 3. However, positioning the upper end of the safety rod to the lower end of the core reduces reactivity of the core. As a countermeasure to solve a lack of this reactivity, the height of fissile zones may be increased. However, in this proposal, the volume ratio of blanket zones per unit volume of the fissile zones is reduced which reduces the breeding ratio of fissile Pu, consequently, the core fails to meet a design target for the fissile Pu breeding ratio. In order to increase the fissile Pu breeding ratio, the height of each of the upper and lower blanket zones in the core must be further increased. The increase in the heights of these zones causes a neutron leak ratio in the axial direction of the core to decrease and the void coefficient, which is an important safety indicator, is worsened. The results of the study done by the inventors regarding a core of a light water reactor loaded with a plurality of fuel assemblies, in which the ratio of Pu-239 in all TRU included in each of these fuel assemblies at the time of zero burnup is in a range of 40 to 60%, including nuclear fuel material obtained by reprocessing, showed that when neutron absorbing material is disposed in the vicinity of the lower end of the core, the void coefficient can be prevented from getting worse by decreasing the height of an upper blanket zone and increasing the height of a lower blanket zone. In the light water breeder reactor, the above-mentioned vicinity of the lower end of the core means an area between the lower end of the core and a position, for example, 5 mm below the lower end of the core, and when the lower blanket zone is formed in the core, this lower blanket zone is also included in the vicinity of the lower end. By making the height of the lower blanket zone higher than that of the upper blanket zone, that is, by making sum of the heights of the upper and lower blanket zones 250 mm or higher and at the same time, making the height of the lower blanket zone 1.6 times or more that of the upper blanket zone, a breeding ratio of 1.01 can be maintained, all restrictive conditions are met, and at the same time, even with the occurrence of a compound event beyond design standards such as the core flow rate is substantially dropped for some reason and all control rods become inoperable, power can be automatically reduced to the power at which the fuel assemblies in the core can be cooled by the capacity of the coolant suppliable to the core by an emergency high-pressure core flooder as shown in FIG. 4. For this reason, a safety margin can be improved in the core of the light water reactor loaded with the fuel assemblies including the nuclear fuel material obtained by reprocessing, the ratio of Pu-239 in all the TRU included in each of these fuel assemblies at the time of zero burnup is in a range of 40 to 60%. When the sum of the heights of the upper and lower blanket zones is over 600 mm or when the height of the lower blanket zone is more than 12 times that of the upper blanket zone, the ratio of Pu-239 contained in all the TRU in the nuclear fuel material in the spent fuel assembly to be taken out from the core will be higher than the ratio of that contained in a new fuel assembly with a burnup of 0. For this reason, when the core flow rate is increased to keep these values in the same range, a pressure loss in the core will exceed the design standard, which will make the structure design of the fuel assemblies difficult. Thus, the sum of the heights of the upper and lower blanket zones should be within a range of 250 to 600 mm. In FIG. 5, a property 31 shows a change in the void coefficient when the height of the upper blanket zone is varied in the core of the light water reactor having a fissile Pu breeding ratio of 1.01, and a property 32 shows a ratio of the height of the lower blanket zone to the height of the upper blanket zone. As shown in FIG. 5, it became clear that when the height of the upper blanket zone was 105 mm or lower, the height of the lower blanket zone would become 1.6 times or more the height of the upper blanket zone and the void coefficient would become more negative than −2×10−4 Δk/k/% void. By making the negative absolute value of the void coefficient larger, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable by the emergency high-pressure core flooder even with the occurrence of a compound event beyond design standards such as the core flow rate being substantially reduced, that is, the void fraction in the core being substantially increased and all control rods being inoperable. When the height of the upper blanket zone is less than 30 mm, the power of fuel pellets located near the upper end of the upper blanket zone, being substantially affected by thermal neutron flux in the upper reflector, will exceed the design standard. Thus, the height of the upper blanket zone is set within a range of 30 to 105 mm. In FIG. 6, a property 33 shows the sum of the heights of the upper and lower blanket zones when the height of the upper blanket zone is varied. It became clear that by making the height of the upper blanket zone 105 mm or lower, the sum of the heights of the upper and lower blanket zones would be 250 mm or higher. Furthermore, when the reactor is operated while the upper end of the neutron absorber filling-zone of the safety rod is positioned in the vicinity of the lower end of the core, there may be a case that boron-10, which is a neutron absorber included in the safety rod, is used up very quickly. For this reason, in some cases, it is also useful to dispose pellets including a neutron absorbing material such as boron, gadolinia, Dy, Sm, Eu, etc. below the lower blanket zone in the fuel rod included in each fuel assembly. The height of the lower blanket zone is made higher than that of the upper blanket zone and the height of the upper fissile zone including TRU in the core is made higher than the height of the lower fissile zone including TRU within a range of 10 to 25 mm. By making the height of the upper fissile zone at least 10 mm higher than the height of the lower fissile zone, the safety margin of the core can be improved even with the occurrence of the above compound event. When the height of the upper fissile zone is more than 25 mm higher than the height of the lower fissile zone, the power in the upper fissile zone will become too high, exceeding the design standard for the power. Next, the results of the study done by the inventors regarding the core of the TRU disappearance reactor disclosed in R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725 is described. As an example of the core of the TRU disappearance reactor, another BWR core with an electric power of 1350 MW, loaded with 720 fuel assemblies, each of which having 397 fuel rods, is described. When TRU recycling is repeated for the purpose of decreasing TRU, in other words, when loading of the fuel assemblies into the core is repeated for every operation cycle, each of which fuel assemblies includes nuclear material obtained by reprocessing and the ratio of Pu-239 in all the TRU included in each of which fuel assembly at the time of zero burnup is at least 5% but less than 40%, fast neutrons leaked out from the core are moderated due to the neutron moderation effect by hydrogen atoms forming the water in a reflector region in the lower portion of the core, causing a large power peak of thermal neutrons. In order to avoid a problem of the power of fuel pellets, which are located in the vicinity of the lower end of a lower fissile zone of each of the fuel assemblies adjoining each other in the core, exceeding the value of the design standard due to the neutron current continuity condition, a lower blanket zone of about 20 mm high is constructed below the lower fissile zone in the TRU disappearance reactor disclosed in R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725. By applying any of the above-described methods (5) and (6) for improving the safety potential, which the inventors have found out, it is no longer necessary to provide the lower blanket zone in the lower portion of the core since the occurrence of the power peak of thermal neutrons in the reflector (cooling water) in the vicinity of the lower end of the core can be controlled by positioning the upper end of a neutron absorber filling-zone of a control rod in the vicinity of the lower end of the core. In other words, the fissile zone, or particularly the lower end of the lower fissile zone, matches the lower end of the core. In the TRU disappearance reactor, the above-mentioned vicinity of the lower end of the core for positioning the upper end of the neutron absorber filling-zone of the control rod means an area between the lower end of the core and a position, for example, 5 mm below the lower end. In FIG. 7, a property 11 shows an average power distribution in the axial direction of the core during the rated power operation, and a property 12 shows an average power distribution in the axial direction of the core when the core flow rate is dropped to 4 kt/h which is a flow rate of the cooling water suppliable by the emergency high-pressure core flooder. In FIG. 8, a property 13 shows an average void fraction distribution in the axial direction of the core corresponding to the property 11, and a property 14 shows an average void fraction distribution in the axial direction of the core corresponding to the property 12. Due to the sudden drop in the core flow rate from a rated value of 20 kt/h to 4 kt/h, the average void fraction distribution in the axial direction of the core rapidly increases from the property 13 to the property 14 shown in FIG. 8. At the same time, the boiling start point shifts to the lower end side of the core, causing the power distribution in the axial direction of the core to shift from the property 11 to the property 12 shown in FIG. 7. When the core flow rate drops in such an extreme way, a large power peak is generated in the reflector in the lower portion of the core and positive reactivity may be introduced into the core in some cases. Each safety rod which is being withdrawn from the core during the rated power operation, is held, while being withdrawn, at a position where the safety rod does not affect the core by introducing negative reactivity (example for, a position 30 cm below the lower end of the core), as usually done in a relatively low-height core having a height of 2 m or less. In FIG. 9, a property 15 shows thermal neutron flux distribution in the axial direction of the core in the core provided with a 20-mm-high lower blanket zone without a neutron absorber filling-zone of a safety rod disposed in the vicinity of the lower end. While the upper end of the neutron absorber filling-zone of the safety rod, which is being withdrawn below the lower end of the core during the reactor operation, is positioned at the lower end of the core and when the core flow rate is suddenly decreased, the safety rod can absorb excess neutrons shifting to the lower portion of the core. A property 16 in FIG. 9 shows the thermal neutron flux distribution in the axial direction of the core at that time. As shown in FIG. 10, even with the occurrence of a compound event beyond design standards such as the core flow rate substantially dropping for some reason and all control rods becoming inoperable, power can be automatically reduced to the power at which the fuel assemblies in the core can be cooled by the capacity of the coolant suppliable to the core from the emergency core flooder. For this reason, a safety margin can be improved in the core of the light water reactor loaded with the fuel assemblies including the nuclear fuel material obtained by reprocessing, the ratio of Pu-239 in all the TRU included in each of these fuel assemblies at the time of zero burnup is at least 5% but less than 40%. In the core of the TRU disappearance reactor, a safety margin of the core can be improved by making the height of the upper blanket zone 100 mm or less. However, when the height of the upper blanket zone is less then 20 mm, the power of fuel pellets located near the upper end of the upper blanket zone, being substantially affected by thermal neutron flux in the upper reflector, will exceed the design standard as in the light water breeder reactor. Thus, the height of the upper blanket zone is set within a range of 20 to 100 mm. The reason for making the height of the upper fissile zone higher than the height of the lower fissile zone within a range of 1.0 to 25 mm in the core of the TRU disappearance reactor is the same as the reason for setting these values in the light water breeder reactor. Various embodiments of the present invention are described below in detail with reference to the figures. (Embodiment 1) A core of a light water reactor core according to embodiment 1, which is a preferred embodiment of the present invention, is described below in detail with reference to FIGS. 11 to 19 and Table 1. TABLE 1NuclideComposition (wt %)Np-2370.5Pu-2382.9Pu-23944.0Pu-24036.2Pu-2415.0Pu-2424.9Am-2413.6Am-242M0.2Am-2431.3Cm-2441.0Cm-2450.3Cm-2460.1 A core 20 of a light water reactor in the present embodiment is for generating an electric power of 1350 MW; however, the power scale is not limited to this value. A core having a different power scale, to which the present embodiment can be applied, can be achieved by changing the number of fuel assemblies loaded into the core 20. An overview of a BWR, which is a light water reactor for generating an electric power of 1350 MW and to which the core 20 of the present embodiment is applied, is described based on FIG. 11. A BWR 19 has the core 20, a steam separator 21, and a stream dryer 22 disposed in a reactor pressure vessel 27. The core 20 is a parfait-type core, which is surrounded by a core shroud 25 in the reactor pressure vessel 27. A plurality of control rods 2 is disposed at the positions which allow the control rods 2 to be inserted into the core 20. These control rods 2 are inserted into the core 20 from below. The steam separator 21 is disposed above the core 20, and the steam dryer 22 is disposed above the steam separator 21. A plurality of internal pumps 26 is provided at the bottom portion of the reactor pressure vessel 27, and impellers of each internal pump 26 are disposed in a downcomer formed between the reactor pressure vessel 27 and the core shroud 25. A main steam pipe 23 and a feed water pipe 24 are connected to the reactor pressure vessel 27. The BWR 19 is equipped with a low-pressure core flooder 31 and a high-pressure core flooder 32 as an emergency core cooling system in case the coolant to be supplied to the core is lost for some reason. As shown in FIG. 12, the core 20 is loaded with 720 fuel assemblies 1. One Y-shaped control rod 2 is provided for every three fuel assemblies 1, and 223 control rods 2 are disposed. Approximately ⅙ of the 223 control rods 2 are control rods for adjusting the reactor power (power adjustment control rods) by being inserted into or withdrawn from the core 20 in the BWR 19 during the operation, and the approximately ⅚ remaining are control rods 2 for inserting into the core 20 when the reactor is shutdown (hereinafter referred to as safety rods), which are being withdrawn from the core 20 in the BWR 19 during the operation. The fuel assembly 1 sequentially forms five zones, i.e., an upper blanket zone 5, an upper fissile zone 6, an inner blanket zone 7, a lower fissile zone 8, and a lower blanket zone 9, from the upper end to the lower end in a portion of an active fuel length (see FIG. 17). In the core 20 loaded with the plurality of fuel assemblies 1, five zones are sequentially formed from the upper end to the lower end, i.e., an upper blanket zone 5A formed by the upper blanket zones 5, an upper fissile zone 6A formed by the upper fissile zones 6, an inner blanket zone 7A formed by the inner blanket zones 7, a lower fissile zone 8A formed by the lower fissile zones 8, and a lower blanket zone 9A formed by the lower blanket zones 9 (see FIG. 1). The zones 5A, 6A, 7A, 8A, and 9A are located at the same positions in the axial direction of the core 20 as the zones 5, 6, 7, 8, and 9 of each fuel assembly 1 respectively. In the fuel assembly 1, as shown in FIG. 13, 271 fuel rods 3, each having a diameter of 10.1 mm, are disposed in a regular triangle lattice in a channel box 4 which is a hexagonal tube. The transverse cross-sectional shape of the fuel assembly 1 is hexagonal. A gap between the fuel rods 3 disposed in the fuel assembly 1 is 1.3 mm. A plurality of fuel pellets (not shown) composed of nuclear fuel material, arranged in the axial direction, is disposed in a cladding tube 36 of each fuel rod 3. Nine fuel rods 3 are disposed in a fuel rod row in an outermost peripheral layer. In the fuel rod 3, as shown in FIG. 14, the plurality of fuel pellets prepared by using the nuclear fuel material obtained by reprocessing is filled in the cladding tube 36 whose a lower end portion and an upper end portion are hermetically sealed with a lower end plug 33 and an upper end plug 35 respectively. An active fuel length 14 is a zone filled with these fuel pellets. A gas plenum 34 is formed between an upper end of the active fuel length 14 and the upper end plug 35 in the hermetically sealed cladding tube 36. In the active fuel length 14 in each fuel rod 3, the above-mentioned five zones, i.e., the upper blanket zone 5, the upper fissile zone 6, the inner blanket zone 7, the lower fissile zone 8, and the lower blanket zone 9 are sequentially formed from the upper end to the lower end. The control rod 2 having a Y-shaped cross section has three blades extending outward from a tie rod located in the center. Each blade is provided with a plurality of neutron absorbing rods filled with B4C, which is a neutron absorber, and disposed around the tie rod at intervals of 120 degrees. The control rod 2 is provided with a follower portion 16 composed of carbon, which is a material having a smaller moderating power than light water, in the insertion end portion to be inserted into the core 20 first. Below the follower portion 16 in the control rod 2 is a neutron absorber filling-zone 15 formed by the neutron absorber filled in each neutron absorber rod (see FIG. 14). When the BWR 19 is in operation at its rated power, the safety rods, which are control rods 2 being completely withdrawn, are withdrawn from the core 20 such that the upper end of the neutron absorber filling-zone 15 is positioned at the lower end of the active fuel length 14 in the fuel rod 3 (see FIG. 14). When the BWR 19 is in operation, the coolant in the downcomer is pressurized by rotation of the internal pumps (coolant supplying apparatuses) 26 and then supplied into the core 20. The coolant supplied into the core 20 is introduced to each fuel assembly 1, and heated by heat generated by nuclear fission of the nuclear fission material, causing part of the coolant to turn into steam. The coolant in a gas-liquid two-phase flow state is introduced from the core 20 to the steam separator 21, where the steam is separated. Moisture in the separated steam is further removed by the steam dryer 22. The steam from which the moisture has been removed is supplied to a turbine (not shown) through the main steam pipe 23 and rotates the turbine. A power generator (not shown) linked to the turbine rotates and generates electric power. The steam exhausted from the turbine is condensed in a condenser (not shown) and turns into condensed water. This condensed water (feed water) is introduced into the reactor pressure vessel 27 through the feed water pipe 24. The liquid coolant separated by the steam separator 22 is mixed with the above feed water in the downcomer and pressurized by the internal pumps 26 again. The rated flow rate of the BWR 19 is 22 kt/h. An arrangement of the fuel assemblies 1 in the core 20 in the state of being an equilibrium core is described with reference to FIG. 15. Fuel assemblies 1E (four-times burned fuel assemblies 1E) in the operation cycle of which is the fifth cycle and staying in the core for the longest time in the in-core fuel dwelling time, are disposed in the outermost peripheral region of the core having a low neutron importance. In a core outer region internally adjacent to the outermost peripheral region, fuel assemblies 1A (fresh fuel assemblies 1A) staying in the core in a first cycle in the in-core fuel dwelling time and having the highest neutron infinite multiplication, are loaded to flatten the power distribution in the radial direction of the core. In a core inner region, fuel assemblies 1B, 1C, and 1D (once-burned fuel assemblies 1B, twice-burned fuel assemblies 1C, and three-times burned fuel assemblies 1D) are disposed, the operation cycles of which are respectively second cycle, third cycle, and fourth cycle in the in-core fuel dwelling time. Such an arrangement is made to flatten the power distribution in the core inner region. Each of the fuel assemblies 1A, 1B, 1C, 1D, and 1E is a fuel assembly 1 shown in FIG. 13, and FIGS. 17 and 18 given later. A plurality of fuel supports (not shown) are provided to a core plate (not shown) disposed to the lower end portion of the core 20. Lower tie-plates (not shown) of four fuel assemblies 1 are supported by one fuel support. Four coolant passages for introducing the coolant to four fuel assemblies are formed in each fuel support, and an orifice (not shown) provided to each fuel support is disposed at the inlet portion of each coolant passage. The core 20 forms two regions in the radial direction, an outermost peripheral region 6 and an inner region 7 located inside the outermost peripheral region 6 (see FIG. 16). Each orifice located in the outermost peripheral region 6, where the power of the fuel assembly 1 is small, has a smaller bore diameter than that of the orifice located in the inner region 7. As shown in FIG. 17, the fuel assembly 1 has five zones, i.e., the upper blanket zone 5, the upper fissile zone 6, the inner blanket zone 7, the lower fissile zone 8, and the lower blanket zone 9, sequentially formed in the portion of the active fuel length from the upper end to the lower end. The height of each zone is as follow: the upper blanket zone 5 (the upper blanket zone 5A) is 70 mm high, the upper fissile zone 6 (the upper fissile zone 6A) is 241 mm high, the inner blanket zone 7 (the inner blanket zone 7A) is 520 mm high, the lower fissile zone 8 (the lower fissile zone 8A) is 225 mm high, and the lower blanket zone 9 (the lower blanket zone 9A) is 280 mm high. When the fuel assembly 1 is a new fuel assembly with a burnup of 0, all the fuel rods 3 in the fuel assembly 1 are filled with depleted uranium oxide pellets in the three blanket zones. The upper fissile zone 6 and the lower fissile zone 8 are filled with mixed oxide fuel having a mixture ratio of 100 parts by average weight of TRU to 172 parts by weight of depleted uranium. A weight ratio of fissile Pu to the total weight of the TRU and the depleted uranium in the mixed oxide fuel, that is, an average enrichment of the fissile Pu is 18 wt %. The TRU is a material extracted, by reprocessing, from the nuclear fuel material contained in the spent fuel assemblies 1. None of the blanket regions are filled with the mixed oxide fuel. Instead of the depleted uranium, the oxide pellets of natural uranium or of the depleted uranium recovered from a spent fuel assembly may be used in each blanket zone. The fuel assembly 1 includes five types of fuel rods 3 shown in FIG. 18. These fuel rods 3 are fuel rods 3A to 3E. The fuel rods 3A to 3E are disposed in the fuel assembly 1 as shown in FIG. 18. In the mixed oxide fuel filled in each of the upper fissile zone 6 and the lower fissile zone 8 of each of the fuel rods 3A to 3E, a fissile Pu enrichment is 10.7 wt % in the fuel rod 3A, 13.5 wt % in the fuel rod 3B, 16.8 wt % in the fuel rod 3C, 18.2 wt % in the fuel rod 3D, and 19.5 wt % in the fuel rod 3E, when the fuel assembly is new fuel assembly having a burnup of 0. The average enrichment of the fissile Pu is 18 wt % for both the upper and lower fissile zones 6 and 8. None of the blanket zones of each fuel rod 3 includes TRU, but the mixed oxide fuel in the upper fissile zone 6 and the lower fissile zone 8 of each fuel rod 3 includes TRU with the composition shown in Table 1 when the burnup is 0. When the fuel assembly 1 is a new fuel assembly, the ratio of Pu-239 in all the TRU is 44 wt %. Table 1 shows a composition of TRU in the nuclear fuel material obtained by reprocessing the nuclear fuel material in a spent fuel assembly, included in a fuel assembly 1, which was originally taken out of the core 20, stayed outside the core for the total of three years, that is, two years in a fuel storage pool and a fuel reprocessing facility and one year in a fuel manufacturing facility, and then loaded again into the core as a new fuel assembly. A plurality of TRU isotopes of the TRU shown in Table 1 is included in the nuclear fuel material in the new fuel assembly 1 obtained by reprocessing. The present embodiment achieves TRU multi-recycling in which, the composition of the TRU in the fuel assembly taken out from the core at the completion of an operation cycle and the composition of the TRU in the fuel assembly newly loaded to the core ready to start the operation cycle are practically uniform. According to the present embodiment in which, the sum of the heights of the upper blanket zone and the lower blanket zone is 350 mm and the height of the lower blanket zone is 4 times the height of the upper blanket zone, a sufficient safety margin can be maintained even with the occurrence of a compound event beyond design standards during the operation of the BWR 19 such as the core flow rate suddenly dropping for some reason and all the control rods being inoperable, by positioning the upper end of the neutron absorber filling-zone 15 of the safety rod, which is a control rod 2 being completely withdrawn at the starting time of the rated operation of the reactor, to the lower end of the active fuel length 14 of the fuel rod 3 (the lower end of the core 20) (see FIG. 14). On the occurrence of such a compound event, the void fraction in the core rapidly rises, the boiling start point of the coolant being slightly sub-cooled and flowing into the core from below the core, shifts to the lower end side of the core, and the power distribution in the axial direction of the core shifts to the lower end side of the core. For this reason, B4C in the neutron absorber filling-zone 15 whose upper end is positioned at the lower end of the core, that is, the lower end of the lower blanket zone 9A, can absorb excess neutrons shifting to the lower end of the core. As a result, in the present embodiment, power can be automatically reduced to the power at which the fuel assemblies 1 in the core 20 can be cooled by the capacity of the coolant suppliable by the emergency high-pressure core flooder 32, and a sufficient safety potential can be maintained even with the occurrence of the compound event beyond design standards. The present embodiment such as this can improve a safety margin without sacrificing the economic efficiency of the light water breeder reactor, which is a light water reactor, even with the occurrence of the above composite event. In the present embodiment, since the height of the lower blanket zone is higher than the height of the upper blanket zone and the height of the upper blanket zone is 70 mm, which is no more than 105 mm, the safety margin of the core upon the occurrence of the above compound event can be further improved. In the present embodiment, since the height of the lower blanket zone is higher than the height of the upper blanket zone and the height of the upper fissile zone is 16 mm, which is at least 10 mm, higher than that of the lower fissile zone, the safety margin of the core upon the occurrence of the above compound event can be further improved. In order to suppress a decrease in reactor reactivity when the upper end of the neutron absorber filling-zone 15 of the safety rod, which is a control rod 2 being completely withdrawn during the rated power operation of the BWR 19, is positioned at the lower end of the active fuel length 14 of the fuel rod 3, the height of the upper fissile zone 6 is set to 241 mm and the height of the lower fissile zone 8 to 225 mm. In addition, in order to maintain a breeding ratio to 1.01 while keeping an impact to the void fraction minimum, the height of the upper blanket zone 5 is set to 70 mm and the height of the lower blanket zone 9 to 280 mm which is 1.6 times more that of the upper blanket zone 5. The present embodiment can meet all the restrictive conditions, maintain a breeding ratio of 1.01, and at the same time, automatically reduce power to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core by the emergency high-pressure core flooder 32 even with the occurrence of a compound event beyond design standards such as the core flow rate significantly dropping for some reason and all the control rods being inoperable. For this reason, the safety margin of the BWR 19, which is a light water breeder reactor, can be improved (see FIG. 4). In the BWR 19 to which the core 20 is applied and which generates the same electric power of 1350 MW as a current ABWR by using a reactor pressure vessel 27 of approximately the same size as that in the ABWR, a higher discharge burnup can be achieved in a core zone which includes the upper fissile zone 6A, the lower fissile zone 8A, and the inner blanket zone 7A, but excludes the upper blanket zone 5A and the lower blanket zone 9A, than a burnup of 45 GWd/t in the light water breeder reactor stated in JP 3428150 B. The discharge burnup of the core zone in the core 20 becomes 53 GWd/t and the discharge burnup of the core 20 including the upper blanket zone 5A and the lower blanket zone 9A becomes 45 GWd/t. According to the present embodiment, MCPR is 1.3 and the void coefficient is −3×10−4 Δk/k/% void, the absolute value of which is one digit higher than the void coefficient −2×10−5 Δk/k/% void of the light water breeder reactor stated in R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725. Furthermore, according to the present embodiment, a breeding rate of 1.01 can be achieved while the ratios of TRU isotopes are maintained practically constant as described above. In the present embodiment, the same effect can be obtained by disposing pellets 21 including a neutron absorbing material such as boron, gadolinia, Dy, Sm, Eu, etc. below the active fuel length 14 of the fuel rod 3 included in each fuel assembly (see FIG. 19) instead of positioning the upper end of the neutron absorber filling-zone 15 of the safety rod being completely withdrawn, below the lower end of the active fuel length 14 of the fuel rod 3 (the lower end of the lower blanket zone 9A) (see FIG. 14). (Embodiment 2) A core of a light water reactor core according to embodiment 2, which is another embodiment of the present invention, is described below in detail with reference to FIGS. 20 to 22 and Table 2. TABLE 2NuclideComposition (wt %)Np-2370.1Pu-2384.8Pu-2398.5Pu-24039.1Pu-2414.5Pu-24226.0Am-2414.5Am-242M0.2Am-2434.8Cm-2444.5Cm-2451.4Cm-2461.1Cm-2470.2Cm-2480.3 A core 20A of a light water reactor in the present embodiment has a structure in which the fuel assembly 1 in the embodiment 1 is replaced with a fuel assembly 1K shown in FIGS. 20 and 22, and other components are the same as in the embodiment 1. In the present embodiment, only components different from the embodiment 1 are described, and the descriptions of the same components as in the embodiment 1 are omitted. The core 20A is also a parfait-type core. The light water reactor to which the core 20A is applied is a BWR 19 shown in FIG. 11, in which the core 20 is replaced with the core 20A. This BWR 19 to which the core 20A is applied, has the same structure, except for the core 20, as the BWR 19 to which the core of the embodiment 1 is applied. The core 20A is a core to be applied to a TRU disappearance reactor. In the fuel assembly 1K (see FIG. 20) disposed in the core 20A, 397 fuel rods 3K, each having a diameter of 7.2 mm, are disposed in a regular triangle lattice in a channel box 4. A gap between the fuel rods 3K is 2.2 mm, and 11 fuel rods 3K are disposed in a fuel rod row in an outermost peripheral layer. As shown in FIG. 21, fuel assemblies 1A to 1D which have experienced a different number of operation cycles are disposed in the core 20A in the state of being an equilibrium core. The fuel assemblies 1D, the operation cycle of which is the fourth cycle, are disposed in the outermost peripheral region of the core. The fuel assemblies 1A, the operation cycle of which is the first cycle, are disposed in a core outer region, and the fuel assemblies 1B, 1C, and 1D, the operation cycles of which are respectively the second cycle, third cycle, and fourth cycle, are dispersedly disposed in a core inner region. There is an intermediate region between the core inner region and the core outer region, in which intermediate region, a plurality of fuel assemblies 1B is disposed in an annular shape. In such core 20A, the power distribution in the radial direction is more flattened. Each of the fuel assemblies 1A to 1D shown in FIG. 21 is a fuel assembly 1K. The fuel assembly 1K has a structure in which the lower blanket is removed from the fuel assembly 1 (see FIG. 22), thus its active fuel length portion is divided into four zones. An upper blanket zone 5 is 30 mm high, an upper fissile zone 6 is 228 mm high, an inner blanket zone 7 is 560 mm high, and a lower fissile zone 8 is 215 mm high. When the fuel assembly 1K is a new fuel assembly with a burnup of 0, the two blanket zones are filled with depleted uranium oxide pellets and the upper fissile zone 6 and the lower fissile zone 8 are filled with TRU oxide fuel in all the fuel rods 3K in the fuel assembly 1K. The enrichment of the fissile Pu in this TRU oxide fuel is 13.0 wt %. The TRU for the fuel assembly 1K can be obtained by reprocessing nuclear fuel material in a spent fuel assembly. Neither blanket zone is filled with the mixed oxide fuel. Each TRU fuel in the upper fissile zone 6 and the lower fissile zone 8 contains TRU with the composition shown in Table 2. When the fuel assembly 1K has a burnup of 0, the ratio of Pu-239 in all the TRU is 8.5 wt %. In the core 20A, an upper blanket zone 5A formed by the upper blanket zones 5, an upper fissile zone 6A formed by the upper fissile zones 6, an inner blanket zone 7A formed by the inner blanket zones 7, and a lower fissile zone 8A formed by the lower fissile zones 8 are sequentially disposed from the upper end to the lower end. In the core 20A, the lower end of the lower fissile zone 8A matches the lower end of the core 20A, and no lower blanket zone is formed. In the present embodiment, as in FIG. 14 of the embodiment 1, a safety rod, which is a control rod 2 being completely withdrawn during the rated power operation of the BWR 19, is withdrawn from the core 20A such that the upper end of a neutron absorber filling-zone 15 filled with B4C is positioned at the lower end of an active fuel length of the fuel rod 3K. The control rod 2 is provided, above the neutron absorber filling-zone 15, with a follower portion 16 composed of carbon which is a material having smaller moderating power than light water. According to the present embodiment in which the height of the upper blanket zone is 30 mm, which is no more than 100 mm, the lower end of the lower fissile zone matches the lower end of the core 20A, and no lower blanket zone is provided, the upper end of the neutron absorber filling-zone 15 of each of the plurality of safety rods being completely withdrawn is positioned at the lower end of the active fuel length 14 of the fuel rod 3, that is, the lower end of the lower fissile zone 8A (see FIG. 14); thus upon the occurrence of a compound event beyond design standards such as the core flow rate suddenly dropping for some reason and all the control rods being inoperable during the operation of the BWR 19, which is a TRU disappearance reactor, the void fraction in the core 20A rapidly rises, the boiling start point of the coolant being slightly sub-cooled and flowing from below the core 20A, shifts to the lower end side of the core 20A, and the power distribution in the axial direction of the core 20 shifts to the lower end side of the core. Therefore, B4C in each neutron absorber filling-zone 15 whose upper end is positioned at the lower end of the lower fissile zone 8A can absorb excess neutrons shifting to the lower end side of the core. As a result, power can be automatically reduced to the power at which the fuel assemblies 1 can be cooled by the capacity of the coolant suppliable to the core 20A from an emergency high-pressure core flooder 32. Even with the occurrence of a compound event beyond design standards, a sufficient safety potential can be maintained in the TRU disappearance reactor. The present embodiment such as this can improve the safety margin without sacrificing the economic efficiency of the TRU disappearance reactor, which is a light water reactor, even with the occurrence of the above compound event. The present embodiment can further improve the safety margin of the core upon the occurrence of the above compound event since it has the upper blanket zone 5A and the height of the upper fissile zone 6A is 13 mm, which is more than 10 mm, higher than that of the lower fissile zone 8A. The height of the upper blanket zone 5 is set to 30 mm and the height of the upper fissile zone 6 is set to 13 mm higher than the height of the lower fissile zone 8 so that when the upper end of the neutron absorber filling-zone 15 of the safety rod being completely withdrawn during the operation of the BWR 19 is positioned at the lower end of the active fuel length of the fuel rod 3 (the lower end of the lower fissile zone 8A), a decrease in core reactivity can be prevented as well as an impact to the void coefficient can be kept to a minimum. According to the present embodiment in which the height of the upper blanket zone is 30 mm, which is no more than 100 mm, the lower end of the lower fissile zone matches the lower end of the core 20A, and no lower blanket zone is provided, all the restrictive conditions can be met and at the same time, even upon the occurrence of a composite event beyond design standards such as the core flow rate substantially dropping for some reason and all the control rods being inoperable, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core 20A from the emergency high-pressure core flooder 32 (see FIG. 10). For this reason, even with the occurrence of such a compound event, the safety margin of the core 20A can be improved. The core 20A can reduce the amount of TRU included in the fuel assembly 1K to less than that of when the burnup of the fuel assembly is 0. In the BWR 19 to which the core 20A is applied, generating the same electric power of 1350 MW as a current ABWR using the reactor pressure vessel of approximately the same size as that in the ABWR, a discharge burnup of 65 GWd/t for the core 20A can be obtained. According to the present embodiment, MCPR is 1.3 and the void coefficient is −4×10−4 Δk/k/% void, the absolute value of which is one digit higher than the void coefficient of −2×10−5 Δk/k/% void in the TRU disappearance reactor stated in R. TAKEDA et al., Proc. of International Conference on Advanced Nuclear Fuel Cycles and Systems. GLOBAL '07 Boise, USA, September, 2007, P. 1725. Furthermore, according to the present embodiment, TRU can be decreased while the ratios of TRU isotopes are maintained. In the present embodiment, as in the embodiment 1, the same effect can be obtained by disposing pellets 21 including a neutron absorbing material such as boron, gadolinia, Dy, Sm, Eu, etc. below the active fuel length 14 of each fuel rod 3 included in each fuel assembly (see FIG. 19) instead of positioning the upper end of the neutron absorber filling-zone 15 of the safety rod being completely withdrawn, at the lower end of the active fuel length 14 of the fuel rod 3 (the lower end of the lower fissile zone 8A) (see FIG. 14). (Embodiment 3) A core of a light water reactor according to embodiment 3, which is another embodiment of the present invention, is described below in detail with reference to FIGS. 23 to 25 and Table 3. TABLE 3NuclideComposition (wt %)Np-2370.2Pu-2385.0Pu-23913.4Pu-24040.8Pu-2414.6Pu-24221.1Am-2414.7Am-242M0.2Am-2434.1Cm-2443.6Cm-2451.1Cm-2460.8Cm-2470.2Cm-2480.2 A core 20B of a light water reactor in the present embodiment has a structure in which the fuel assemblies 1K in the core 20A in the embodiment 2 are replaced with fuel assemblies 1L described in FIGS. 24 and 25, and other components are the same as in the embodiment 2. The light water reactor to which the core 20B is applied is a BWR 19 shown in FIG. 11, in which the core 20 is replaced with the core 20B. This BWR 19 to which the core 20B is applied, has the same components, except for the core 20, as the BWR 19 to which the core of the embodiment 1 is applied. The core 20B is a core applied to a TRU disappearance reactor. The components of the present embodiment which are different from the embodiment 2 are described, and the descriptions of the components that are the same as the embodiment 2 are omitted. In the fuel assembly 1L used in the present embodiment (see FIG. 24), 397 fuel rods 3L, each having a diameter of 7.6 mm, are disposed in a regular triangle lattice in a channel box 4. A gap between the fuel rods 3L is 1.8 mm, and 11 fuel rods 3L are disposed in a fuel rod row in an outermost peripheral layer. As shown in FIG. 23, fuel assemblies 1A to 1D which have experienced a different number of operation cycles are disposed in the core 20B in the state of being an equilibrium core. The fuel assemblies 1D, the operation cycle of which is the fourth cycle, are disposed in the outermost peripheral region of the core. The fuel assemblies 1A, the operation cycle of which is the first cycle, are disposed in a core outer region, and the fuel assemblies 1B, 1C, and 1D, the operation cycles of which are respectively the second cycle, third cycle, and fourth cycle, are dispersedly disposed in a core inner region. There is an intermediate region between the core inner region and the core outer region, in which intermediate region, a plurality of the fuel assemblies 1B is disposed in an annular shape. In such core 20B, the power distribution in the radial direction is more flattened. Each of the fuel assemblies 1A to 1D shown in FIG. 23 is a fuel assembly 1L. In the fuel assembly 1L, as in the fuel assembly 1K, its active fuel length portion is divided into four zones (see FIG. 25). An upper blanket zone 5 is 50 mm high, an upper fissile zone 6 is 183 mm high, an inner blanket zone 7 is 560 mm high, and a lower fissile zone 8 is 173 mm high. When the fuel assembly 1L is a new fuel assembly with a burnup of 0, the two blanket zones are filled with depleted uranium oxide pellets and the upper fissile zone 6 and the lower fissile zone 8 are filled with TRU oxide fuel in all the fuel rods 3L in the fuel assembly 1L. The enrichment of the fissile Pu in this TRU fuel is 18.0 wt %. Neither blanket zone is filled with the mixed oxide fuel. Each TRU oxide fuel in the upper fissile zone 6 and the lower fissile zone 8 contains TRU with the composition shown in Table 3. This TRU is a material obtained by reprocessing nuclear fuel material in a spent fuel assembly. When the fuel assembly 1L has a burnup of 0, the ratio of Pu-239 in all the TRU is 13.4 wt %. In the core 20B as well, an upper blanket zone 5A formed by the upper blanket zones 5, an upper fissile zone 6A formed by the upper fissile zones 6, an inner blanket zone 7A formed by the inner blanket zones 7, and a lower fissile zone 8A formed by the lower fissile zones 8 are sequentially disposed from the upper end of the core 20B to the lower end of the core 20B. In the core 20B, the lower end of the lower fissile zone 8A matches the lower end of the core 20B, and no lower blanket zone is formed. In the present embodiment, as in FIG. 14 of the embodiment 1, when the BWR 19 is operated at the rated power, the upper end of a neutron absorber filling-zone 15 with each of safety rods (some of control rods 2) being completely withdrawn, is positioned at the lower end of an active fuel length of the fuel rod 3L (the lower end of the lower fissile zone 8A). The Y-shaped control rod 2 is provided, above the neutron absorber filling-zone 15, with a follower portion 16 composed of carbon which is a material having a smaller moderating power than light water. According to the present embodiment in which the height of the upper blanket zone is 50 mm, which is no more than 100 mm, the lower end of the lower fissile zone matches the lower end of the core 20B, and no lower blanket zone is provided, the upper end of the neutron absorber filling-zone 15 of each safety rod being completely withdrawn, is positioned at the lower end of the active fuel length 14 of the fuel rod 3, that is, the lower end of the lower fissile zone 8A (see FIG. 14); thus upon the occurrence of a compound event beyond design standards such as the core flow rate suddenly dropping for some reason and all the control rods being inoperable during the operation of the BWR 19, which is a TRU disappearance reactor, the void fraction in the core 20B rapidly rises, the boiling start point of the coolant being slightly sub-cooled and flowing from below the core 20B, shifts to the lower end side of the core 20B, and the power distribution in the axial direction of the core shifts to the lower side of the core 20B. Therefore, B4C in each neutron absorber filling-zone 15 whose upper end is positioned at the lower end of the lower fissile zone 8A can absorb excess neutrons shifting to the lower end side of the core 20B. As a result, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core 20A from an emergency high-pressure core flooder 32. Even with the occurrence of a compound event beyond design standards, a sufficient safety potential can be maintained in the TRU disappearance reactor. The present embodiment such as this can improve the safety margin without sacrificing the economic efficiency of the TRU disappearance reactor even with the occurrence of the above compound event. The present embodiment can further improve the safety margin of the core upon the occurrence of the above compound event since it has the upper blanket zone and the height of the upper fissile zone is 10 mm higher than that of the lower fissile zone. The height of the upper blanket zone 5 is set to 50 mm and the height of the upper fissile zone 6 is set to 10 mm higher than the height of the lower fissile zone 8 so that when the upper end of the neutron absorber filling-zone 15 of the safety rod being completely withdrawn during the operation of the BWR 19 is positioned at the lower end of the active fuel length of the fuel rod 3 (the lower end of the lower fissile zone 8A), a decrease in core reactivity can be prevented as well as an impact to the void coefficient can be kept to a minimum. According to the present embodiment, all the restrictive conditions can be met and at the same time, even upon the occurrence of a composite event beyond design standards such as the core flow rate substantially dropping for some reason and all control rods being inoperable, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core 20B from the emergency high-pressure core flooder 32. For this reason, the safety margin of the core 20B can be improved upon the occurrence of such a compound event. The core 20B can reduce the amount of TRU included in the fuel assembly 1L to less than that of when the burnup of the fuel assembly is 0. In the BWR 19 to which the core 20B is applied, generating the same electric power of 1350 MW as a current ABWR using a reactor pressure vessel of approximately the same size as that in the ABWR, a discharge burnup of 65 GWd/t can be achieved for the core 20B. According to the present embodiment, the void coefficient is −6×10−4 Δk/k/% void and MCPR is 1.3 and TRU can be decreased while the ratios of TRU isotopes are maintained. (Embodiment 4) A core of a light water reactor core according to embodiment 4, which is another embodiment of the present invention, is described below in detail with reference to FIGS. 26, 27, and Table 4. TABLE 4NuclideComposition (wt %)Np-2370.2Pu-2384.9Pu-2397.0Pu-24035.2Pu-2414.6Pu-24229.4Am-2413.9Am-242M0.2Am-2435.2Cm-2445.7Cm-2451.6Cm-2461.5Cm-2470.3Cm-2480.3 A core 20C of a light water reactor in the present embodiment has a structure in which the fuel assemblies 1K in the core 20A in the embodiment 2 are replaced with fuel assemblies 1M shown in FIGS. 26 and 27, and other components are the same as in the embodiment 2. The light water reactor to which the core 20C is applied is a BWR 19 shown in FIG. 11, in which the core 20 is replaced with the core 20C. This BWR 19 to which the core 20C is applied, has the same components, except for the core 20, as the BWR 19 to which the core of the embodiment 1 is applied. The core 20C is a core applied to a TRU disappearance reactor. The components of the present embodiment which are different from the embodiment 2 are described, and the descriptions of the components that are the same as the embodiment 2 are omitted. In the fuel assembly 1M used in the present embodiment (see FIG. 26), 397 fuel rods 3M, each having a diameter of 7.1 mm, are disposed in a regular triangle lattice in a channel box 4. A gap between the fuel rods 3M is 2.3 mm, and 11 fuel rods 3M are disposed in a fuel rod row in an outermost peripheral layer. The arrangement of the fuel assemblies in an equilibrium core in the present embodiment is the same as that shown in FIG. 21 in the embodiment 2. In the fuel assembly 1M, as in the fuel assembly 1K, its active fuel length portion is divided into four zones (see FIG. 27). An upper blanket zone 5 is 30 mm high, an upper fissile zone 6 is 240 mm high, an inner blanket zone 7 is 560 mm high, and a lower fissile zone 8 is 227 mm high. When the fuel assembly 1M is a new fuel assembly with a burnup of 0, the two blanket zones are filled with depleted uranium oxide pellets and the upper fissile zone 6 and the lower fissile zone 8 are filled with TRU oxide fuel in all the fuel rods 3M in the fuel assembly 1M. The enrichment of the fissile Pu in this TRU fuel is 11.6 wt %. Neither blanket zone is filled with the mixed oxide fuel. Each TRU fuel in the upper fissile zone 6 and the lower fissile zone 8 contains TRU with the composition shown in Table 4. This TRU is a material obtained by reprocessing nuclear fuel material in a spent fuel assembly. When the fuel assembly 1M is a new fuel assembly, the ratio of Pu-239 in all the TRU is 7.0 wt %. In the core 20C as well, an upper blanket zone 5A formed by the upper blanket zones 5, an upper fissile zone 6A formed by the upper fissile zones 6, an inner blanket zone 7A formed by the inner blanket zones 7, and a lower fissile zone 8A formed by the lower fissile zones 8 are sequentially disposed from the upper end of the core 20C to the lower end of the core 20C. In the core 20C, the lower end of the lower fissile zone 8A matches the lower end of the core 20C, and no lower blanket zone is formed. In the present embodiment, as in FIG. 14 of the embodiment 1, when the BWR 19 is operated at the rated power, the upper end of a neutron absorber filling-zone 15 of each of the safety rods (some of Y-shaped control rods 2) being completely withdrawn, is positioned at the lower end of the active fuel length of the fuel rod 3M (the lower end of the lower fissile zone 8A). The control rod 2 is provided, above the neutron absorber filling-zone 15, with a follower portion 16 composed of carbon which is a material having a smaller moderating power than light water. According to the present embodiment in which the height of the upper blanket zone is 30 mm, which is no more than 100 mm, the lower end of the lower fissile zone matches the lower end of the core 20C, and no lower blanket zone is provided, the upper end of the neutron absorber filling-zone 15 of each safety rod being completely withdrawn, is positioned at the lower end of the active fuel length 14 of the fuel rod 3, that is, the lower end of the lower fissile zone 8A (see FIG. 14); thus upon the occurrence of a compound event beyond design standards such as the core flow rate suddenly dropping for some reason and all the control rods being inoperable during the operation of the BWR 19, which is a TRU disappearance reactor, the void fraction in the core 20C rapidly rises, the boiling start point of the coolant being slightly sub-cooled and flowing from below the core 20C, shifts to the lower end side of the core 20C, and the power distribution in the axial direction of the core shifts to the lower side of the core 20C. Therefore, B4C in each neutron absorber filling-zone 15 whose upper end is positioned at the lower end of the lower fissile zone 8A can absorb excess neutrons shifting to the lower side of the core 20C. As a result, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core 20C from an emergency high-pressure core flooder 32. Even with the occurrence of a compound event beyond design standards, a sufficient safety potential can be maintained in the TRU disappearance reactor. The present embodiment such as this can improve the safety margin without sacrificing the economic efficiency of the TRU disappearance reactor even with the occurrence of the above compound event. The present embodiment can further improve the safety margin of the core upon the occurrence of the above compound event since it has the upper blanket zone and the height of the upper fissile zone is 13 mm, which is more than 10 mm, higher than that of the lower fissile zone. The height of the upper blanket zone 5 is set to 30 mm and the height of the upper fissile zone 6 is set to 13 mm higher than the height of the lower fissile zone 8 so that when the upper end of the neutron absorber filling-zone 15 of the safety rod being completely withdrawn during the operation of the BWR 19 is positioned at the lower end of the active fuel length of the fuel rod 3 (the lower end of the lower fissile zone 8A), a decrease in core reactivity can be prevented as well as an impact to the void coefficient can be kept to a minimum. According to the present embodiment, all the restrictive conditions can be met and at the same time, even upon the occurrence of a composite event beyond design standards such as the core flow rate substantially dropping for some reason and all the control rods being inoperable, power can be automatically reduced to the power at which the fuel assemblies can be cooled by the capacity of the coolant suppliable to the core 20C from the emergency high-pressure core flooder 32. For this reason, the safety margin of the core 20C can be improved even with the occurrence of such a compound event. The core 20C can reduce the amount of TRU included in the fuel assembly 1M to less than that of when a burnup of the fuel assembly is 0. In the BWR 19 to which the core 20C is applied, generating the same electric power of 1350 MW as a current ABWR using a reactor pressure vessel of approximately the same size as that in the ABWR, a discharge burnup of 65 GWd/t can be achieved. In the present embodiment, the void coefficient is −3×10−4 Δk/k/% void and MCPR is 1.3 and TRU can be decreased while the ratios of TRU isotopes are maintained. (Embodiment 5) A core of a light water reactor core according to embodiment 5, which is another embodiment of the present invention, is described below in detail with reference to FIG. 28. In the light water reactor core of the present embodiment, each fuel assembly 1 loaded to the core 20 in the embodiment 1 is structured as shown in FIG. 28, and other components are the same as in the embodiment 1. In an active fuel length portion of the fuel assembly, as shown in FIG. 28, five zones, i.e., an upper blanket zone 5, an upper fissile zone 6, an inner blanket zone 7, a lower fissile zone 8, and a lower blanket zone 9 are sequentially formed from the upper end to the lower end. The height of each zone is as follows: the upper blanket zone 5 is 105 mm high; the upper fissile zone 6 is 248 mm high; the inner blanket zone 7 is 520 mm high; the lower fissile zone 8 is 232 mm high; and the lower blanket zone 9 is 280 mm high. In the core 20 loaded with a plurality of fuel assemblies 1 forming each zone shown in FIG. 28, an upper blanket zone 5A formed by the upper blanket zones 5, an upper fissile zone 6A formed by the upper fissile zones 6, an inner blanket zone 7A formed by the inner blanket zones 7, a lower fissile zone 8A formed by the lower fissile zones 8, and a lower blanket zone 9A formed by the lower blanket zones 9 are sequentially disposed from the upper end to the lower end. Each effect generated by the embodiment 1 can be obtained by the core of the present embodiment. In the present embodiment, which considers safety within the design standards only, a higher burnup can be achieved than in the embodiment 1, and in the BWR 19 to which the core of the present embodiment is applied, generating the same electric power of 1350 MW as a current ABWR using a reactor pressure vessel of approximately the same size as that in the ABWR, a discharge burnup of 66 GWd/t for the core zone and a discharge burnup of 55 GWd/t for the core including the upper and lower blanket zones can be achieved. In the present embodiment, the void coefficient is −5×10−5 Δk/k/% void and MCPR is 1.3, and a breeding ratio of 1.01 can be achieved while the ratios of TRU isotopes are maintained practically constant as described above. (Embodiment 6) A core of a light water reactor core according to embodiment 6, which is another embodiment of the present invention, is described below in detail with reference to FIGS. 29 and 30. In the core of the present embodiment, each fuel assembly 1 loaded to the core 20 in the embodiment 1 is structured as shown in FIG. 29, and other components are the same as in the embodiment 1. In the present embodiment, when the light water reactor to which the core of the present embodiment is applied, is operated at the rated power, the upper end of a neutron absorber filling-zone 15 of each of the safety rods (some of Y-shaped control rods 2) being completely withdrawn, is positioned at ⅕ the height of a lower blanket zone 9 from the lower end of the lower blanket zone 9 (see FIG. 30). In an active fuel length portion of this fuel assembly, as shown in FIG. 29, five zones, i.e., an upper blanket zone 5, an upper fissile zone 6, an inner blanket zone 7, a lower fissile zone 8, and the lower blanket zone 9 are sequentially formed from the upper end to the lower end. The height of each zone is as follows: the upper blanket zone 5 is 60 mm high; the upper fissile zone 6 is 235 mm high; the inner blanket zone 7 is 450 mm high; the lower fissile zone 8 is 219 mm high; and the lower blanket zone 9 is 280 mm high. In the core of the present embodiment, as in the core 20, an upper blanket zone 5A, an upper fissile zone 6A, an inner blanket zone 7A, a lower fissile zone 8A, and a lower blanket zone 9A are formed at the same axial positions as the upper blanket zone 5, the upper fissile zone 6, the inner blanket zone 7, the lower fissile zone 8, and the lower blanket zone 9 formed in each fuel assembly shown in FIG. 29. The core of the present embodiment can be obtained each effect generated by the embodiment 1. In the BWR 19 to which the core of the present embodiment is applied, generating the same electric power of 1350 MW as a current ABWR using a reactor pressure vessel 27 of approximately the same size as that in the ABWR, a discharge burnup of 54 GWd/t for the core zone and a discharge burnup of 45 GWd/t for the core 20 including the upper and lower blanket zones can be achieved. In addition, in the present embodiment, the void coefficient is −3×10−4 Δk/k/% void and MCPR is 1.3, and a breeding ratio of 1.01 can be achieved while the ratios of TRU isotopes are maintained practically constant as described above.
	abstract	A positioning apparatus for a CRD handling assembly for a nuclear reactor. The positioning apparatus includes at least one linear slide rail, a drive screw coupled to the at least one slide rail, an elevator movably coupled to the drive screw, and at least one linear bearing attached to the elevator. The linear bearing is slidably coupled to the at least one slide rail.
047566566	summary	BACKGROUND OF THE INVENTION: 1. Field of the Invention The present invention relates to apparatus for handling an end effector device or tool from a remote location. The invention relates particularly to apparatus for handling tools in the irradiated underwater environment of a nuclear reactor from a remote location above the water level in the reactor vessel. 2. Description of the Prior Art: In the event of damage to a nuclear reactor core, it becomes necessary to remove the damaged elements. This operation can be particularly difficult and time consuming in the event that the reactor core has melted and refused. In such a case, it is necessary to remove loose debris from the reactor vessel and to cut away the fused material. To do this, tools such as hydraulic grippers, saws, chisels, and the like must be lowered into the reactor vessel from a remote position, so as to minimize man-rem exposure. Therefore, there must be provided means which will reach the work area from a level approximately 30 feet thereabove. Since work must also be done at various levels within the core, the device must be readily adjustable in length. Furthermore, in order to minimize man-rem exposure, the device must be remotely adjustable in length in the irradiated underwater environment of the reactor vessel, while providing a control line path between the end effector tool and associated remote control apparatus. In the event of hydraulically controlled end effectors, the handling apparatus must provide fluid-tight seals for all hydraulic connections. In summary, there is a need for an apparatus operable from a remote location which can be used to position, retrieve and operate various end effector tools at various depths in an irradiated underwater environment. Heretofore, no such apparatus has been available. SUMMARY OF THE INVENTION It is a general object of the present invention to provide an improved apparatus for the remote handling of a device in an irradiated underwater environment, which apparatus affords unique structural and operating advantages. An important feature of the invention is the provision of apparatus of the type set forth which is readily adjustable in length. In connection with the foregoing feature, another feature of the invention is the provision of a sectional apparatus, the sections of which can be readily connected and disconnected remotely underwater. Another feature of the invention is the provision of apparatus of the type set forth, which both supports the device and provides control line connections between the device and an associated remote control unit. Another feature of the invention is the provision of apparatus of the type set forth, which is of relatively compact, simple and economical construction. These and other features of the invention are attained by providing sectional apparatus for remotely handling a device in an irradiated underwater environment, said apparatus comprising: an elongated structure including one or more elongated structural sections; each of said sections carrying a control line segment, each of said sections including first and second coupling means respectively disposed at opposite ends thereof, each of said first and second coupling means being respectively connectable to second and first coupling means of adjacent sections for interconnecting said sections and the control line segments thereof in end-to-end relationship to form said structure with said control line segments cooperating to form a control line, said second coupling means at one end of said structure being connectable to the associated device for support thereof and for connecting said control line thereto; and support means including a second coupling means connected to said first coupling means at the other end of said structure, said support means including means for connecting said control line to associated control means for controlling the operation of the device. The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompaying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spririt, or sacrificing any of the advantages of the present invention.
042773059	summary	BACKGROUND OF THE INVENTION The present invention pertains generally to plasmas and more specifically to devices for generating thermonuclear neutrons. Prior art methods for generating hot plasmas have been limited to inertially and magnetically confined systems. A typical example of an inertially confined system is the implosion of fuel microcapsules by impingent high power laser or electron beams. Typical examples of magnetically confined systems comprise theta-pinch devices, Z-pinch devices, various toroidal configurations such as stellarators, syllacs tokomacs, and toroidal Z-pinch devices, which form a magnetic bottle to confine a hot plasma for a predetermined period at sufficiently high temperatures and pressures to produce thermonuclear neutrons. Both the inertially confined systems and the magnetically confined systems have various disadvantages and limitations. In both types of systems it is difficult and expensive to bring to bear sufficient energy on the hot plasma to insure significant thermonuclear burn. End losses in linear theta-pinch devices and various instabilities defeating confinement in other magnetic confinement systems due to rapid growth relative to containment times, also result in limited burn of the thermonuclear plasma. Damage to inertial confinement targets prior to implosion due to deposition of beam energy directly on the fuel element also limits neutron yield. This has been alleviated somewhat by pulse shaping and limiting the duration of the beam pulse. However, these measures impose extreme design limitations on the beam pulse generator which typically reduce efficiency. Moreover, the necessity of beam focusing to fuel microcapsule diameters requires expensive and easily damaged optics. Additionally, absorption characteristics of fuel microcapsule for impingent laser beams does not provide a good impedance match to insure maximum deposition of energy. Although magnetic confinement systems protect the containment vessel by magnetic energy fields and provide a means for recovering magnetic energy during fuel expansion, such systems are not inherent to inertially confined systems and must be added separately. SUMMARY OF THE INVENTION The present invention overcomes the disadvantages and limitations of the prior art by providing a beam heated linear theta-pinch device for producing hot plasmas. According to the present invention, both magnetic and beam energy are utilized to supplement each other to produce a hot plasma. The implosive nature and rapid burn characteristics of the present invention eliminate end loss and plasma instability problems associated with magnetically contained systems. Since the beam energy is not directed at the fuel microcapsule but rather at a surrounding plasma, problems of fuel target damage, beam focusing, pulse shape and duration, and energy absorption properties are alleviated. Moreover, the magnetic field of the linear theta-pinch device of the present invention protects the cylindrical walls from the microexplosion and allows magnetic energy to be recovered during fuel expansion as well as providing a simple cylindrical geometry minimizing construction and operational difficulties. It is therefore an object of the present invention to provide a device for generating a hot plasma. It is also an object of the present invention to provide a device for generating thermonuclear neutrons. Another object of the present invention is to provide a device for generating hot plasmas which is simple in operation and easy to implement. Another object of the present invention is to provide a device for producing hot plasmas which is inexpensive to implement. Another object of the present invention is to provide a device for generating hot plasmas which overcomes the disadvantages and limitations of inertial confinement systems. Another object of the present invention is to provide a device for producing hot plasmas which overcomes the disadvantages and limitations of inertial confinement systems. Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. The detailed description, indicating the preferred embodiments of the invention is given only by way of illustration since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. The foregoing Abstract of the Disclosure is for the purpose of providing a nonlegal brief statement to serve as a searching and scanning tool for scientists, engineers, and researchers and is not intended to limit the scope of the invention as disclosed herein, nor is it intended to be used in interpreting, or in any way limiting, the scope or fair meaning of the appended claims.
	claims	1. A temperature sensor array comprising:a plurality of temperature sensors including twelve passive thermocouples each spaced apart from one another by at least one foot on an axis and each having a width perpendicular to the axis of less than one inch, wherein the temperature sensors,are configured to be inserted into an instrumentation tube within a nuclear reactor so that the axis extends in the instrumentation tube and the temperature sensors are spaced in the instrumentation tube,measure temperatures of the instrumentation tube from about 100 degrees Fahrenheit to about 3000 degrees Fahrenheit, andinclude only materials with melting temperatures and cross-sections such that the temperature sensors do not fail within an operating or transient nuclear reactor environment. 2. The array of claim 1, further comprising:an axial column to which the plurality of temperature sensors are attached, wherein the axial column is configured to be inserted into the instrumentation tube. 3. The array of claim 2, wherein the axial column is a continuous and flexible metallic rod. 4. The array of claim 1, further comprising:at least one communicative connector configured to transmit data from at least one of the temperature sensors to a remote monitor. 5. The array of claim 1, wherein the plurality of temperature sensors are thermocouples configured to measure temperature without an external power source. 6. The array of claim 1, wherein the plurality of temperature sensors are bare along the axis. 7. The array of claim 1, wherein the nuclear reactor is a boiling water reactor. 8. The array of claim 1, wherein the temperature sensors are further configured to measure a temperature range including normal operating temperatures of the nuclear reactor and temperatures associated with absence of coolant in a transient scenario of the nuclear reactor. 9. A nuclear reactor comprising:a core containing nuclear fuel;an instrumentation tube extending into the core, wherein the instrumentation tube has an opening outside the reactor to permit enclosed access to the core; anda temperature sensor array extending into the instrumentation tube, wherein the temperature sensor array includes a plurality of temperature sensors including twelve passive thermocouples each aligned at different axial positions of the instrumentation tube at least one foot apart from each other and each having a width perpendicular to the instrumentation tube of less than one inch, and wherein the temperature sensors are uninsulated from the instrumentation tube in order to measure thermal temperature of the reactor. 10. The nuclear reactor of claim 9, wherein the temperature sensor array further includes,an axial column to which the plurality of temperature sensors are attached at the different axial positions, andat least one communicative connector extending outside the instrumentation tube and configured to transmit data from at least one of the temperature sensors to a remote monitor. 11. The nuclear reactor of claim 10, wherein the plurality of temperature sensors are aligned and spaced along the axial column so as to be present at a plurality of axial levels within the core. 12. The nuclear reactor of claim 9, wherein the plurality of temperature sensors are passive thermocouples configured to measure a temperature range of the instrumentation tube including normal operating temperatures of the nuclear reactor and temperatures associated with absence of coolant in a transient scenario of the nuclear reactor. 13. The nuclear reactor of claim 12, wherein the nuclear reactor is a boiling water reactor, and wherein the reactor further comprises:a plurality of instrumentation tubes extending into the core, wherein each instrumentation tube has an opening outside the reactor to permit enclosed access to the core; anda plurality of the temperature sensor arrays each extending into a respective instrumentation tube of the plurality of instrumentation tubes, wherein the temperature range is from approximately 100 degrees Fahrenheit to approximately 3000 degrees Fahrenheit. 14. A method of monitoring a nuclear reactor, the method comprising:installing a plurality of temperature sensors including twelve passive thermocouples each at different axial positions at least one foot apart from each other within an instrumentation tube of the nuclear reactor and having a width perpendicular to the instrumentation tube of less than one inch, wherein the temperature sensors measure a temperature of the instrumentation tube ranging from normal operating temperatures of the nuclear reactor to temperatures associated with absence of coolant in a transient scenario of the nuclear reactor. 15. The method of claim 14, wherein the temperature ranges from approximately 100 degrees Fahrenheit to approximately 3000 degrees Fahrenheit, the method further comprising:determining a coolant level in the nuclear reactor from temperatures measured by the plurality of temperature sensors. 16. The method of claim 15, wherein the determining includes correlating a threshold temperature to an absence of coolant condition and comparing the temperatures measured by the plurality of temperature sensors to the threshold temperature. 17. The method of claim 15, wherein the determining is performed in real-time and determines a current coolant level in the nuclear reactor. 18. The method of claim 14, wherein the installing includes inserting a temperature sensor array containing the plurality of temperature sensors aligned at different axial positions into the instrumentation tube. 19. The method of claim 14, wherein the temperature sensors are uninsulated from the instrumentation tube and measure temperature throughout the range passively with heat applied only from the reactor.
	description	The present invention relates to a container sterilization method and container sterilization equipment in which a plurality of electron-beam irradiating devices are provided in parallel along a container conveyance path. The container sterilization equipment includes two heads that irradiate an object to be treated with electron beams and two filament power supplies that supply power to the filaments of the two heads. Each of the filament power supplies for the respective heads has a switch that compares a beam depletion threshold value estimated according to the magnitude of a beam control signal with an actual beam current measured value. When the beam current measured value is not higher than the beam depletion threshold value, it is decided that beams are depleted. This stops power supply to the filament of the beam-depleted head while keeping filament power to other heads. Thus, in an electron-beam irradiating device with power sharing multiple beam heads, discharge from one head stops only an abnormal head but keeps beams to other heads. This eliminates the need for stopping the operations of all the heads. Patent Literature 1: Japanese Patent No. 3952708 For example, electron beam sterilization equipment that sterilizes a container by irradiation of electron beams can sterilize about 600 containers per minute and is interlocked with a filling device provided downstream of the equipment. If an electron-beam irradiating device requires replacement of an electron beam emitter because of an accident or deterioration, the electron beam sterilization equipment needs to be stopped for a sufficient time period. Moreover, each container is irradiated with electron beams for 0.1 seconds. If sparking occurs on the electron-beam irradiating device, it takes about 0.1 to 0.2 seconds to recover the original irradiation output. Thus, a container passing through the sparked electron-beam irradiating device may directly contaminate a sterilizing chamber or the filling device that is equipment downstream of the electron-beam irradiating device. In this case, the overall equipment needs to be stopped to be cleaned. Thus, in electron-beam container sterilization equipment for high-speed sterilization, it is important to operate an electron-beam irradiating device with minimum spark and prevent an unsterilized container from being transported and contaminating downstream equipment in the event of sparking. An object of the present invention is to provide a container sterilization method and container sterilization equipment which can continuously operate an electron-beam irradiating device by shortening the stop time of the device, prevent an unsterilized container from contaminating a downstream device even if sparking temporarily reduces an electron beam output, and suppress the occurrence of sparking. A container sterilization method according to a first aspect for sterilizing a container with electron beams irradiated from electron-beam irradiating devices while transporting the container along a carrier path, the method including: irradiating substantially identical outside surface of the container with electron beams irradiated from one or more upstream electron-beam irradiating device and one or more downstream electron-beam irradiating device spaced to each other with a predetermined distance along the carrier path; and controlling a sum of electron beam outputs irradiated from the upstream and downstream electron-beam irradiating devices by means of a sterilization controller so as to at least allow sterilization on the surface of the container. A container sterilization method according to a second aspect, in the method of the first aspect, when the electron beam output irradiated from the upstream electron-beam irradiating device changes from a set range, changing the electron beam output irradiated from the downstream electron-beam irradiating device so as to control the sum of the electron beam outputs from the upstream and downstream electron-beam irradiating devices to be equal to or higher than the set range of an electron beam output that allows external sterilization on the container when the container irradiated with the changed electron-beam output at the upstream electron-beam irradiating device is transported to the downstream electron-beam irradiating device. A container sterilization method according to a third aspect, in the method of the first or second aspect, wherein each of the electron-beam irradiating device has a vacuum chamber, the method further including: monitoring a vacuum state in the vacuum chamber of each of the electron-beam irradiating devices; and controlling an electron beam output of the electron-beam irradiating device including the vacuum chamber with a low degree of vacuum to be smaller than an electron beam output of the electron-beam irradiating device including the vacuum chamber with a high degree of vacuum in order to prevent sparking in the electron-beam irradiating device including the vacuum chamber with the low degree of vacuum. Container sterilization equipment according to a fourth aspect for externally sterilizing a container with electron beams irradiated from electron-beam irradiating devices facing a carrier path while transporting the container along the carrier path, including one or more upstream electron-beam irradiating device and one or more downstream electron-beam irradiating device spaced to each other with a predetermined distance along the carrier path for irradiating substantially identical surface of the container with electron beams, and a sterilization controller for controlling a sum of electron beam outputs irradiated from the upstream electron-beam irradiating device and the downstream electron-beam irradiating device so as to allow sterilization on the surface of the container, wherein the sterilization controller controls such that, when the electron beam output from the upstream electron-beam irradiating device changes from a set range, the container irradiated from the upstream electron-beam irradiating device with the electron beam is transported so as to face the downstream electron-beam irradiating device, and an electron beam output from the downstream electron-beam irradiating device is controlled to change the sum of the upstream electron beam output and the downstream electron beam output so as to at least allow external sterilization on the container. Container sterilization equipment according to a fifth aspect, in the configuration of the fourth aspect, further including a rejecting device provided downstream of the downstream electron beam sterilization equipment on the carrier path so as to eject the container on the carrier path, the sterilization controller operating the rejecting device so as to eject, from the carrier path, the container with a changed electron beam output irradiated from the upstream electron-beam irradiating device. Container sterilization equipment according to a sixth aspect externally sterilizes a container with electron beams irradiated from electron-beam irradiating devices having a vacuum chamber and facing a carrier path while transporting the container along the carrier path, wherein the electron-beam irradiating devices includes one or more upstream electron-beam irradiating device and one or more downstream electron-beam irradiating device spaced to each other with a predetermined distance along the carrier path, the upstream and downstream electron-beam irradiating devices irradiating substantially identical sterilization surface of the container with electron beams, the electron-beam irradiating device includes a vacuum chamber, the container sterilization equipment includes a vacuum sensor for detecting a degree of vacuum in the vacuum chamber and a sterilization controller, and the sterilization controller controls an electron beam output of the electron-beam irradiating device including the vacuum chamber with a low degree of vacuum such that the electron beam output thereof is smaller than an electron beam output of the electron-beam irradiating device including the vacuum chamber with a high degree of vacuum; meanwhile, the sterilization controller controls a sum of electron beam outputs irradiated from the upstream electron-beam irradiating device and the downstream electron-beam irradiating device so as to allow sterilization on the surface of the container. According to the invention of the first aspect, the electron-beam irradiating devices sterilize the substantially identical surfaces of the container with electron beams. Thus, if the electron beam irradiation dose of the electron-beam irradiating device is reduced by a failure, maintenance, deterioration caused by an extended operating time, or secular change, the maintained electron beam output of the other not reduced electron-beam irradiating device can be increased by the sterilization controller. This can eliminate a stop time and enables a continuous operation. According to the configuration of the second aspect, if an electron dose irradiated upstream to the container is reduced below a set amount because of sparking or the like, the downstream electron-beam irradiating device increases an electron dose irradiated to the container, thereby externally sterilizing the container with reliability. This prevents an insufficiently sterilized container from being transported to downstream equipment, eliminating contamination of the downstream equipment. This may less frequently stop the sterilization equipment, leading to a longer operating time. According to the invention of the third aspect, a vacuum state is monitored in the vacuum chamber of the electron-beam irradiating device, allowing the electron-beam irradiating device having a low degree of vacuum to operate with a reduced electron beam output. This can prevent sparking that is likely to occur in the electron-beam irradiating device having a low degree of vacuum, thereby suppressing the occurrence of insufficiently sterilized containers. According to the configuration of the fourth aspect, the electron-beam irradiating devices that sterilize the substantially identical surfaces of the container are spaced with the predetermined distance on the conveyance path. The electron beam output of the electron-beam irradiating device with an electron beam irradiation dose reduced by a failure, maintenance, deterioration, or secular change is adjusted to as to enable an extended continuous operation. In the event of an accident that may reduce the electron beam output of the electron-beam irradiating device or stop the electron-beam irradiating device, the electron beam output of the other electron-beam irradiating device is increased so as to continue an extended operation without stopping the sterilization equipment. This can flexibly respond to the accident. According to the invention of the fifth aspect, the container with a changed electron beam output may be deteriorated in quality by excessive irradiation of electron beams. Such a container is ejected as an insufficiently sterilized container from the conveyance path by the rejecting device, preferably achieving continuous sterilization of containers. According to the invention of the sixth aspect, a vacuum state of the vacuum chamber is monitored by the vacuum sensor in the electron-beam irradiating devices that are spaced with the predetermined distance on the conveyance path, and the sterilization controller reduces the electron beam output of the electron-beam irradiating device including the vacuum chamber with a low degree of vacuum and increases the electron beam output of the electron-beam irradiating device including the vacuum chamber with a high degree of vacuum. This controls the sum of the electron beam outputs of the upstream electron-beam irradiating device and the downstream electron-beam irradiating device so as to allow sterilization on the sterilization surfaces of the container, thereby preventing the occurrence of sparking in the electron-beam irradiating device with a low degree of vacuum and considerably reducing the occurrence of insufficiently sterilized containers. Referring to FIGS. 1 to 5, a first embodiment of electron-beam container sterilization equipment according to the present invention will be described below. (Equipment Overview) As shown in FIG. 1, a plurality of first to seventh shielded chambers 11A to 11G are connected in series via container entrances/exits 11a to 11h. The first to seventh shielded chambers 11A to 11G contain first to seventh container carrier devices 12A to 12G that transport containers B at regular intervals P. The first shielded chamber 11A on the entrance side has a circular container carrier path L1 along which the first container carrier device 12A transports the containers B. The first shielded chamber 11A prevents leakage of electron beams (X-rays) to the container entrance 11a. The second shielded chamber 11B and the third shielded chamber 11C are external sterilization chambers that sterilize the outer surfaces of the containers B. In the second shielded chamber 11B, a first upstream electron-beam irradiating device 21 and a first downstream electron-beam irradiating device 22 are spaced with a certain distance (e.g., twice as large as the interval P) on the outer periphery of a container carrier path L2 formed by the second container carrier device 12B. In the third shielded chamber 11C, a second upstream electron-beam irradiating device 23 and a second downstream electron-beam irradiating device 24 are spaced with a certain distance (twice as large as the interval P) on the outer periphery of a container carrier path L3. The fourth shielded chamber 11D is an internal sterilization chamber that sterilizes the inner surfaces of the containers B. Along the upper part of a circular fourth container carrier path L4 where the containers B are transported by the fourth container carrier device 12D, a plurality of internal electron-beam irradiating devices (not shown) shaped like nozzles insertable into the containers B from the openings of the containers B are paired with internal sterilization power supplies so as to be spaced at regular intervals. The fifth to seventh shielded chambers 11E to 11G are exit-side shielded chambers that prevent leakage of electron beams (X-rays) from the container exit 11h. Circular carrier paths L5 to L7 are formed along which the fifth to seventh container carrier devices 12E to 12G transport the containers B. The intermediate sixth shielded chamber 11F contains a rejecting device 26 that ejects the insufficiently sterilized containers B from the circular carrier path L6. (Container Carrier Device) For example, as shown in FIGS. 3 and 4, the second container carrier device 12B includes a turning table 14 rotatably supported by a main shaft 13 raised on a pedestal and container holding devices 16 that are provided at the regular intervals P on the outer periphery of the turning table 14 so as to hold the necks of the containers B with pairs of holding arms 15R and 15L. Reference numeral 17 denotes a pivot shaft that pivotally penetrates the turning table 14. An arm open/close cam 18 is attached to the upper end of the pivot shaft 17 so as to open the holding arms 15R and 15L restrained with a spring in a closing direction. An open/close cam follower 20 is attached to the lower end of the pivot shaft 17 via an arm member so as to follow a holding open/close cam 19 fixed below the turning table 14. The second container carrier device 12B was described above. The first, third, and fifth to seventh container carrier devices 12A, 12C, and 12E to 12G other than the fourth container carrier device 12D are substantially identical in configuration to the second container carrier device 12B. The fourth container carrier device 12D has an elevating mechanism (not shown) that relatively moves up and down the containers B held by the container holding devices 16 and the internal electron-beam irradiating devices shaped like nozzles, inserting the internal electron-beam irradiating devices from the openings of the containers B. (Electron-Beam Irradiating Device) As shown in FIG. 2, the second shielded chamber 11B contains a first upstream electron-beam irradiating device 21 and a first downstream electron-beam irradiating device 22 that irradiate sterilization surfaces F on the containers B with electron beams. The electron-beam irradiating devices 21 and 22 are spaced with, for example, a distance P′ twice as large as the interval P upstream and downstream on the outer periphery of the carrier path L2. The third shielded chamber 11C contains a second upstream electron-beam irradiating device 23 and a second downstream electron-beam irradiating device 24 that irradiate external sterilization surfaces R on the containers B with electron beams. The electron-beam irradiating devices 23 and 24 are spaced with, for example, the distance P′ twice as large as the interval P upstream and downstream on the outer periphery of the carrier path L3. In this configuration, the sterilization surfaces F and R are irradiated with electrons at angles larger than 90° with respect to the irradiation direction of electron beams because of the irradiation characteristics of electron beams. The electron-beam irradiating devices 21 to 24 include a first upstream power supply 21PS, a first downstream power supply 22PS, a second upstream power supply 23PS, and a second downstream power supply 24PS, respectively, that supply predetermined power for generating electron beams. A sterilization controller 25 controls the power supplies 21PS, 22PS, 23PS, and 24PS so as to control the outputs of electron beams irradiated from the electron-beam irradiating devices 21 to 24. Moreover, the sterilization controller 25 controls the rejecting device 26 of the sixth shielded chamber 11F. As shown in FIG. 5, each of the electron-beam irradiating devices 21 to 24 has a cylindrical housing 31 in a vertical position. The housing 31 has an irradiation hole 34 having a predetermined position formed at a predetermined height on the side of the housing 31. A metallic thin film 34a is attached to the irradiation hole 34 so as to seal a vacuum chamber 30 in a vacuum in the housing 31. A filament 32 is placed in the housing 31 and an electrode 33 having transparent windows 33a formed is provided around the filament 32. Power is supplied from the first upstream power supply 21PS (22PS to 24PS) to the electrodes 33 and then is supplied to the filament 32 through a filament power supply 35. This generates electron beams between the filament 32 and the electrode 33. Electron beams are irradiated from the transparent windows 33a to the containers B through the vacuum chamber 30 and the irradiation hole 34. The vacuum chambers 30 of the electron-beam irradiating devices 21 to 24 has a first upstream vacuum sensor 21VS, a first downstream vacuum sensor 22VS, a second upstream vacuum sensor 23VS, and a second downstream vacuum sensor 24VS, respectively, that detect a vacuum state. Degrees of vacuum in the vacuum chambers 30 are inputted to the sterilization controller 25 by the vacuum sensors 21VS to 24VS. In this configuration, the first electron-beam irradiating devices 21 and 22 of the second shielded chamber 11B and the second electron-beam irradiating devices 23 and 24 of the third shielded chamber 11C are substantially identical in configuration except for irradiation of electron beams for sterilizing the substantially half sterilization surfaces F and R that are symmetrical to each other on the container B. Thus, only the first electron-beam irradiating devices 21 and 22 of the second shielded chamber 11B will be described below and the explanation of the second electron-beam irradiating devices 23 and 24 of the third shielded chamber 11C is omitted. Based on the degree of vacuum of the vacuum chamber 30 in each of the first electron-beam irradiating devices 21 and 22, the sterilization controller 25 is set so as to reduce the electron beam output of the electron-beam irradiating device (e.g., 21) including the vacuum chamber 30 with a low degree of vacuum and increase the electron beam output of the electron-beam irradiating device 22 including an electron beam generator with a high degree of vacuum. This is because a decrease in the degree of vacuum of the vacuum chamber 30 is likely to cause sparking between the electrode 33 and the housing 31 grounded in the electron-beam irradiating device 21 (22 to 24), temporarily (for 0.1 to 0.2 seconds) stopping outputting electron beams. This may reduce an electron dose irradiated to the sterilization surface F of the container B and cause poor sterilization. Moreover, the sterilization controller 25 controls the sum of electron beam outputs irradiated from the first electron-beam irradiating devices 21 and 22 so as to allow sterilization on the sterilization surface F of the container B. The sterilization controller 25 can detect the output of electron beams irradiated from the first upstream electron-beam irradiating device 21 to the container B according to a supplied current if the output is changed (reduced) from a set range (threshold) by sparking between the grounded housing 31 and the electrode 33. The occurrence of sparking temporarily (for 0.1 to 0.2 seconds) stops the output of electron beams irradiated from the first upstream electron-beam irradiating device 21. Thus, the sum of electron beam outputs irradiated from the first electron-beam irradiating devices 21 and 22 may be reduced below the set value (threshold) that allows sterilization on the sterilization surface F of the container B. In addition to sparking, the output of electron beams may be stopped if the metallic thin film 34a of the irradiation hole 34 is broken by deterioration of the electron-beam irradiating device. At this point, the sterilization controller 25 controls the electron beam output of the first downstream electron-beam irradiating device 22 such that after a time period during which the container B is transported to the subsequent irradiation position by two pitches, the electron beam output irradiated to the container B is increased and the sum of the electron beam output of the first downstream electron-beam irradiating device 22 and the electron beam output irradiated by the first upstream electron-beam irradiating device 21 (in a state of a reduced output) is not lower than the lower limit of the set value (threshold) that allows sterilization on the sterilization surface F of the container B. In this way, the electron beam output irradiated to the sterilization surface F of the container B is large enough to at least allow sterilization on the sterilization surface F, preventing the containers B from passing through being unsterilized. This can prevent the containers B transported to the container carrier paths L3 to L7 from contaminating the interiors of the third to seventh shielded chambers 11C to 11G. Since the container B with a varying electron beam output may excessively radiate electron beams, the sterilization controller 25 operates the rejecting device 26 of the sixth shielded chamber 11F so as to remove the container B from the container carrier path L6. In this case, at least the first downstream electron-beam irradiating device 22 can preferably output electron beams so as to allow sterilization on the sterilization surface F of the container B even if the electron beam output of the first upstream electron-beam irradiating device 21 is stopped. For example, if the sterilization equipment can treat (sterilize) 600 containers B per minute, each of the electron-beam irradiating devices 21 to 24 irradiates the container B with electron beams for 0.1 seconds. The container B is transported in 0.2 seconds from the first and second upstream electron-beam irradiating devices 21 and 23 to the first and second downstream electron-beam irradiating devices 22 and 24. The sterilization controller 25 has to adjust the outputs of the first and second downstream electron-beam irradiating devices 22 and 24 in 0.2 seconds. In the first embodiment, an electron beam output is set based on a vacuum state in each of the vacuum chambers 30 of the electron-beam irradiating devices 21 to 24. The electron beam outputs of the upstream electron-beam irradiating devices 21 and 23 and the downstream electron-beam irradiating devices 22 and 24 may be set based on the operating times and conditions of the upstream electron-beam irradiating devices 21 and 23 and the downstream electron-beam irradiating devices 22 and 24. For the sterilization surfaces F and R, the second shielded chamber 11B and the third shielded chamber 11C each include two of the first and second electron-beam irradiating devices 21 to 24. At least three electron-beam irradiating devices may be provided in each of the shielded chambers. In the first embodiment, the electron beam output is controlled according to a lapse of time. The electron beam output may be controlled by detecting the angle of rotation of the turning table 14 with a detector (e.g., a rotary encoder) and monitoring the position of the container B. Referring to FIGS. 6 and 7, a second embodiment of electron-beam container sterilization equipment according to the present invention will be described below. An electron-beam irradiating device according to the second embodiment is configured in consideration of sparking that is more likely to occur with a reduction in the degree of vacuum in a vacuum chamber. Vacuum sensors 21VS to 24VS are provided to detect degrees of vacuum in vacuum chambers 30 of electron-beam irradiating devices 21 to 24. The same parts as those of the first embodiment are indicated by the same reference numerals and the explanation thereof is omitted. For example, “Equipment overview” and “container carrier device” are identical in configuration to those of the first embodiment and thus the explanation thereof is omitted. Furthermore, “electron-beam irradiating device” is identical to that of the first embodiment except for the provision of the vacuum sensors. FIGS. 2 to 4 are also identical to the configuration of the present embodiment and thus the explanation thereof is omitted. As shown in FIG. 1, a plurality of first to seventh shielded chambers 11A to 11G are connected in series via container entrances/exits 11a to 11h. The first to seventh shielded chambers 11A to 11G contain first to seventh container carrier devices 12A to 12G that transport containers B at regular intervals P. The first shielded chamber 11A on the entrance side has a circular container carrier path L1 formed along which the first container carrier device 12A transports the containers B. The first shielded chamber 11A prevents leakage of electron beams (X-rays) to the container entrance 11a. The second shielded chamber 11B and the third shielded chamber 11C are external sterilization chambers that sterilize the outer surfaces of the containers B. In the second shielded chamber 11B, a first upstream electron-beam irradiating device 21 and a first downstream electron-beam irradiating device 22 are spaced with a certain distance (twice as large as the interval P) on the outer periphery of a container carrier path L2 formed by the second container carrier device 12B. In the third shielded chamber 11C, a second upstream electron-beam irradiating device 23 and a second downstream electron-beam irradiating device 24 are spaced with a certain distance (twice as large as the interval P) on the outer periphery of a container carrier path L3. The fourth shielded chamber 11D is an internal sterilization chamber that sterilizes the inner surfaces of the containers B. Along the upper part of a circular fourth container carrier path L4 where the containers B are transported by the fourth container carrier device 12D, a plurality of internal electron-beam irradiating devices (not shown) shaped like nozzles insertable into the containers B from the openings of the containers B are paired with internal sterilization power supplies 30 so as to be spaced at predetermined intervals. The fifth to seventh shielded chambers 11E to 11G are exit-side shielded chambers that prevent leakage of electron beams (X-rays) from the container exit 11h. Circular carrier paths L5 to L7 are formed along which the fifth to seventh container carrier devices 12E to 12G transport the containers B. The intermediate sixth shielded chamber 11F contains a rejecting device 26 that ejects the insufficiently sterilized containers B from the circular carrier path L6. (Container Carrier Device) For example, as shown in FIGS. 3 and 4, the second container carrier device 12B includes a turning table 14 rotatably supported by a main shaft 13 raised on a pedestal and container holding devices 16 that are provided at the regular intervals P on the outer periphery of the turning table 14 so as to hold the necks of the containers B with pairs of holding arms 15R and 15L. Reference numeral 17 denotes a pivot shaft that pivotally penetrates the turning table 14. An arm open/close earn 18 is attached to the upper end of the pivot shaft 17 so as to open the holding arms 15R and 15L restrained with a spring in a closing direction. An open/close cam follower 20 is attached to the lower end of the pivot shaft 17 via an arm member so as to follow a holding open/close cam 19 fixed below the turning table 14. The second container carrier device 12B was described above. The first, third, and fifth to seventh container carrier devices 12A, 12C, and 12E to 12G other than the fourth container carrier device 12D are substantially identical in configuration to the second container carrier device 12B. The fourth container carrier device 12D has an elevating mechanism (not shown) that relatively moves up and down the containers B held by the container holding devices 16 and the internal electron-beam irradiating devices shaped like nozzles, inserting the internal electron-beam irradiating devices from the openings of the containers B. (Electron-Beam Irradiating Device) As shown in FIG. 2, the second shielded chamber 11B contains a first upstream electron-beam irradiating device 21 and a downstream electron-beam irradiating device 22 that irradiate sterilization surfaces F on the containers B with electron beams. The electron-beam irradiating devices 21 and 22 are spaced with, for example, a distance P′ twice as large as the interval P upstream and downstream on the outer periphery of the carrier path L2. The third shielded chamber 11C contains a second upstream electron-beam irradiating device 23 and a second downstream electron-beam irradiating device 24 that irradiate sterilization surfaces R on the containers B with electron beams. The electron-beam irradiating devices 23 and 24 are spaced with, for example, the distance P′ twice as large as the interval P upstream and downstream on the outer periphery of the carrier path L3. In this configuration, the sterilization surfaces F and R are irradiated with electrons at angles larger than 90° with respect to the irradiation direction of electron beams because of the irradiation characteristics of electron beams. The electron-beam irradiating devices 21 to 24 include a first upstream power supply 21PS, a first downstream power supply 22PS, a second upstream power supply 23PS, and a second downstream power supply 24PS, respectively, that supply predetermined power for generating electron beams. A sterilization controller 25 controls the power supplies 21PS, 22PS, 23PS, and 24PS so as to control the outputs of electron beams irradiated from the electron-beam irradiating devices 21 to 24. Moreover, the sterilization controller 25 controls the rejecting device 26 of the sixth shielded chamber 11F. As shown in FIG. 5, each of the electron-beam irradiating devices 21 to 24 has a cylindrical housing 31 in a vertical position. The housing 31 has an irradiation hole 34 having a predetermined position formed at a predetermined height on the side of the housing 31. A metallic thin film 34a is attached to the irradiation hole 34 so as to seal the vacuum chamber 30 in a vacuum in the housing 31. A filament 32 is placed in the housing 31 and an electrode 33 having transparent windows 33a formed is provided around the filament 32. Power is supplied from the first upstream power supply 21PS (22PS to 24PS) to the electrodes 33 and then is supplied to the filament 32 through a filament power supply 35. This generates electron beams between the filament 32 and the electrode 33. Electron beams are irradiated from the transparent windows 33a to the containers B through the vacuum chamber 30 and the irradiation hole 34. The vacuum chambers 30 of the electron-beam irradiating devices 21 to 24 has a first upstream vacuum sensor 21VS, a first downstream vacuum sensor 22VS, a second upstream vacuum sensor 23VS, and a second downstream vacuum sensor 24VS, respectively, that detect a vacuum state. Degrees of vacuum in the vacuum chambers 30 are inputted to the sterilization controller 25 by the vacuum sensors 21VS to 24VS. In this configuration, the first electron-beam irradiating devices 21 and 22 of the second shielded chamber 11B and the second electron-beam irradiating devices 23 and 24 of the third shielded chamber 11C are substantially identical in configuration except for irradiation of electron beams for sterilizing the substantially half sterilization surfaces F and R that are symmetrical to each other on the container B. Thus, only the first electron-beam irradiating devices 21 and 22 of the second shielded chamber 11B will be described below and the explanation of the second electron-beam irradiating devices 23 and 24 of the third sterilizing chamber 11C is omitted. Based on the degree of vacuum of the vacuum chamber 30 in each of the first electron-beam irradiating devices 21 and 22, the sterilization controller 25 is set so as to reduce the electron beam output of the electron-beam irradiating device (e.g., 21) including the vacuum chamber 30 with a low degree of vacuum and increase the electron beam output of the electron-beam irradiating device 22 including an electron beam generator with a high degree of vacuum. This is because a decrease in the degree of vacuum of the vacuum chamber 30 is likely to cause sparking between the electrode 33 and the housing 31 grounded in the electron-beam irradiating device 21 (22 to 24), temporarily (for 0.1 to 0.2 seconds) stopping outputting electron beams. This may reduce an electron dose irradiated to the sterilization surface F of the container B and cause poor sterilization. Moreover, the sterilization controller 25 controls the sum of electron beam outputs irradiated from the first electron-beam irradiating devices 21 and 22 so as to allows sterilization on the sterilization surface F of the container B. In addition to the same effect as the first embodiment, the configuration of the second embodiment can considerably reduce the occurrence of sparking by lowering an electron beam output, though the vacuum chambers 30 of the electron-beam irradiating devices 21 to 24 decrease in degree of vacuum. For example, if the sterilization equipment can treat (sterilize) 600 containers B per minute, each of the electron-beam irradiating devices 21 to 24 irradiates the container B with electron beams for 0.1 seconds. The container B is transported in 0.2 seconds from the first and second upstream electron-beam irradiating devices 21 and 23 to the first and second downstream electron-beam irradiating devices 22 and 24. The sterilization controller 25 has to adjust the outputs of the first and second downstream electron-beam irradiating devices 22 and 24 in 0.2 seconds. In the second embodiment, an electron beam output is set based on a vacuum state in each of the vacuum chambers 30 of the electron-beam irradiating devices 21 to 24. The electron beam outputs of the upstream electron-beam irradiating devices 21 and 23 and the downstream electron-beam irradiating devices 22 and 24 may be set based on the operating times and conditions of the upstream electron-beam irradiating devices 21 and 23 and the downstream electron-beam irradiating devices 22 and 24. For the sterilization surfaces F and R, the second shielded chamber 11B and the third shielded chamber 11C each include two of the first and second electron-beam irradiating devices 21 to 24. At least three electron-beam irradiating devices may be provided in each of the shielded chambers.
	claims	1. A passive reactivity control apparatus comprising:a first reservoir having a first reservoir portion and a second reservoir portion, the first reservoir portion and the second reservoir portion being spaced apart;a first conduit interposed between and fluidly connecting the first reservoir portion and the second reservoir portion of the first reservoir;a second reservoir spaced apart from the first reservoir, the second reservoir interposed between the first reservoir portion and the second reservoir portion of the first reservoir, the second reservoir being located within a selected portion of a nuclear fission reactor core;a second conduit interposed between and fluidly connecting the second reservoir portion and the second reservoir;a driver material disposed in the first reservoir portion and the second reservoir portion of the first reservoir and the first conduit, a volume of the driver material thermally expanding and contracting in response to an increase and decrease of a nuclear fission reactor thermal operational parameter, respectively; anda neutron absorption parameter modifying material disposed in the second reservoir portion and the second reservoir, the neutron absorption parameter modifying material being different from the driver material, a portion of the neutron absorption parameter modifying material being in physical contact with a portion of the driver material in the second reservoir portion, the neutron absorption parameter modifying material being driveable by the driver material from the second reservoir portion to the second reservoir through the second conduit upon expansion of the volume of the driver material, the neutron absorption parameter modifying material being drivable by the driver material from the second reservoir to the second reservoir portion through the second conduit upon contraction of the volume of the driver material. 2. The apparatus of claim 1, further comprising a plurality of members disposed in the second reservoir, the plurality of members being arranged to mitigate free-surface effect in the second reservoir. 3. The apparatus of claim 1, wherein the driver material includes a gas. 4. The apparatus of claim 3, wherein the gas includes at least one gas chosen from He, Xe, Kr, Ar, Ne, Rn, N2, CO2, and NH3. 5. The apparatus of claim 1, wherein the driver material includes a liquid. 6. The apparatus of claim 5, wherein the neutron absorption parameter modifying material includes a liquid that is immiscible with the driver material. 7. The apparatus of claim 1, wherein the driver material includes a solid. 8. The apparatus of claim 7, wherein the solid includes at least one solid chosen from a ferritic martensitic steel and a zirconium alloy. 9. The apparatus of claim 1, wherein the nuclear fission reactor thermal operational parameter includes at least one temperature chosen from reactor coolant temperature, reactor coolant vapor temperature, and fuel temperature. 10. The apparatus of claim 1, wherein the nuclear fission reactor thermal operational parameter includes at least one flux chosen from neutron flux, beta flux, gamma flux, and neutrino flux. 11. The apparatus of claim 1, wherein the neutron absorption parameter modifying material includes a neutron absorber. 12. The apparatus of claim 11, wherein the neutron absorber includes at least one neutron absorber chosen from In, Li-6, Eu, Ag, Dy, B, Hf, Gd, Pm, Cd, Sm, binary combinations thereof, and eutectic combinations thereof. 13. The apparatus of claim 11, wherein the neutron absorber includes nuclear fission fuel material. 14. The apparatus of claim 13, wherein the nuclear fission fuel material includes at least one nuclear fission fuel material chosen from U dissolved in Pb, U—Fe, U—Mn, Pu—Mn, U—Cr, Pu—Cr, Pu—Fe eutectic, and Pu—Mg eutectic. 15. The apparatus of claim 1, wherein the neutron absorption parameter modifying material includes a moderator. 16. The apparatus of claim 15, wherein the moderator includes at least one moderator chosen from Li-7, C, SiC, a hydrogenous material, water, ammonia, acetone, a metal hydride, a metal deuteride, a suspension of carbon in water, and a suspension of SiC in water. 17. The apparatus of claim 1, further comprising a high-Z material distributed in the driver material. 18. The apparatus of claim 17, wherein the high-Z material includes at least one material chosen from W wool, Ta, Au, Ag, Re, and Os. 19. The apparatus of claim 1, wherein:the driver material has a first density;the neutron absorption parameter modifying material has a second density that is different from the first density; andthe driver material is immiscible with the neutron absorption parameter modifying material. 20. The apparatus of claim 19, wherein the second density is greater than the first density. 21. The apparatus of claim 19, wherein the first density is greater than the second density.
	summary
046577327	abstract	A barrier system for a high temperature reactor. The reactor utilizes spherical fuel elements consisting of coated particles of a fissionable material embedded in a graphite matrix, the coating forming a first safety barrier against the release of fissionable material, and the graphite matrix a second such safety barrier. The reactor is surrounded by a prestressed concrete pressure vessel clad on the inside with a metal liner. The metal liner acts as a third safety barrier, while the concrete body of the prestressed concrete pressure vessel forms the fourth, and outermost safety barrier. A plurality of passages are located in the pressure vessel which are closed off by closure means. The closure means provide sealment between the third and fourth barriers in the area of the passages. By utilizing the concrete pressure vessel as a safety barrier in this manner, the need for a separate protective reactor housing is eliminated.
	description	Not Applicable Not Applicable Not Applicable This application relates to the field of atomic physics and atomic engineering, particularly to the manipulation and control of electrons for the production of electric energy through an efficient and effective process for the extraction of electrons from atoms and molecules. Currently a number of methods are available to produce electric energy; among these are electric generators, alternators, photovoltaic cells, chemical batteries, fuel cells, piezoelectric apparatus, thermoelectric converters and electrostatic devices. All of these involve the conversion of one form of energy into another. Here generators, alternators and piezoelectric devices convert mechanical energy, where specifically, kinetic energy or mechanical strain is thus converted into electrical. The first two require turbines or motors to rotate armatures within magnetic fields, while the third takes advantage of the structural strain within certain crystals. Other systems involve the conversion of chemical energy into electrical as within batteries. Among the electrostatic devices is another mechanical conversion generator called the Van de Graff. In locations where hydroelectric generation is impractical, electricity is primarily generated by electromechanical means driven by heat engines used to power steam turbine generator apparatus, with the output usually contributing electricity to the local or national power grid. The burning of fossil fuels such as coal, oil, oil products and natural gas feeds these engines and accounts for 83% of the electricity produced in the U.S. Nuclear fission reactors are also used to provide steam to drive power plant turbines. However, the coal, oil, natural gas and nuclear fuels are not renewable and in the coming decades the available supplies will dwindle drastically. Consequently, over the past four decades much effort has been devoted to the development of alternative systems that would make use of renewable energy sources. These would include wind and geothermal generation, river and tidal current generation, and solar energy production. There are two major systems that take advantage of solar energy. A satisfactory output for both systems is restricted to the daylight hours while the sun shines precisely upon the solar components. One consists of the costly photovoltaic cells, which produce electricity directly in small quantity, and the other utilize mirrors to concentrate solar heat energy onto high-pressure steam boilers that in turn power the turbines. 1. Hundreds of thousands of kilometers of transmission lines are required to connect each building or user to the nationwide power grid. 2. During transmission, there is a substantial loss of electric energy directly from the transmission lines to the atmosphere. 3. Transmission of electricity over great distances requires elaborate substations at specific intervals to maintain the required energy level within the above grade or below grade lines. 4. With conventional equipment there is excessive wear of moving parts within the governor, gearbox, motor or turbine, and generator or alternator. 5. There is excessive wear of moving parts within wind generators that include propeller blade pitch control, speed control governor, gearbox, and generator. 6. The friction developed by the moving parts of the primary generating systems is another negative result with high levels of energy converted into heat rather than electricity. 7. Corrosion of parts and mechanisms of systems powered by hydroelectric means, and those powered by river or tidal currents. 8. All the systems discussed require many years or even decades to recover the initial investments. 9. If nuclear, the expensive materials must be constantly protected and when exhausted as fuel, the radioactive waste must be stored, guarded and monitored indefinitely. 10. Coal-fired power plants produce 40% of atmospheric carbon dioxide as well as other pollutants. 11. Because the commercial solar powered systems require motorized tracking mechanisms for the mirror or the photovoltaic panels, there is a sizeable reduction in the net electric energy produced. 12. For commercial installations to be effective with either solar powered system, the unsightly panel arrays typically occupy vast areas of land. These are just some of the disadvantages of the current systems. The process of the present application, however, overcomes the previous obstacles. The most idyllic and advantageous electrical system would consist of individual electric power generation units that could be placed upon or near each dwelling, structure or complex making it completely independent from any other electric energy source. It would not contain moving parts that would experience undue wear or parts that would deteriorate over short periods of use. It should efficiently and economically produce electric energy, continuously, twenty-four hours per day, regardless of the weather, and where there was any production in excess of immediate needs could be diverted to the local or national power grid or stored for future use. And if the power generation units were fueled by something other than fossil or nuclear fuels, these features would make it the most practical and environmentally friendly systems. For the first time the technology derived from the present application makes practical such independent power generation units for individual dwellings. The process can be scaled to accommodate the system energy requirements of most implementations, whether individual homes, multiunit complexes, multistory buildings, factory facilities, neighborhoods and more. Since each dwelling or structure can be individually powered, thousands of kilometers of transmission lines and hundreds of costly substations can be eliminated. It can also accommodate portable power units for use at construction sites or as temporary emergency power stations or even as smaller individual transportable units. The process can be scaled down further to provide power to some appliances or portable devices individually. To accommodate electric automobiles, battery charger units can be placed in many locations including those that are remote. For the production of electric energy the present application represents the first new technology to emerge in several decades. Electrons extracted from the immediate particulate environment consisting of atoms and molecules fuel the process. And once the system is fully energized, it requires only an infrequent enhancement to sustain operation. The process is further explained below. Given that the process involves the production of positive ions, a discussion of the prior art related to this subject is presented. Currently, a small number of methods are available to convert electrically neutral atoms or molecules into ions. Neutral atoms contain equal numbers of electrons to the number of protons in the nucleus, while neutral molecules contain electrons in equal numbers to the sum of protons in the discrete nuclei. To ionize a neutral atom or molecule, it is necessary to either add one or more electrons to form a negative ion or knock out one or more electrons to form a positive ion. Ions, for a variety of purposes, have been deliberately produced now for nearly a century. There are several common methods to form negative ions, however, exclusively positive ions are extremely difficult and costly to produce. This is due in part to the high-energy requirements by the current systems that include the continuous application of extreme temperatures during thermal ionization or extremely high voltages continuously applied during coronal discharge. Additional restrictions are imposed by the extremes in the ionization potential or energy requirements to remove the valance or outer electrons of various atoms and molecules. The ionization potential is equal to the binding energy of the electron and is measured in electron volts (eV) or kilojoules per mole. The process of the present application also overcomes these difficulties. Exposing the target atoms or molecules to either electrical discharge from a cathode in the form of a disk or pointed emitter, or coronal discharge of electrons in a high voltage system usually produces negatively charged ions. Similarly, a variety of electrostatic precipitators are used to place a negative electric charge on larger airborne particles such as dust or pollen. These systems also carry a number of disadvantages that include the consumption of high energy continuously over the course of operation. Another is the occasional production of unwanted ions, those that carry a charge opposite from what a system requires. On occasion, with coronal discharge, for example when negative ions are the objective, an emitted electron will act as a projectile and knockoff or repel an electron from a passing target particle to form the unwelcome positive ion. Through each of the electrostatic methods electrons are emitted to where the successful production of negative ions depends upon the intermittent capture and retention of an electron by a passing atom or molecule. Because the atom or molecule passing the emitter is electrically neutral, it does not attract nor necessarily retain the emitted electron. It is clearly a hit-or-miss situation, resulting with a high percentage of target particles remaining unmodified, and simultaneously being encumbered by the presence of accidental positive ions. However, if the primary objectives of an implementation include an efficient process for the extraction of electrons from atoms and molecules with the continuous production of positive ions, then none of the current methods are suitable. As previously indicated, the electric generating capabilities of the process of the present application can be used as independent power generation units for individual buildings, small groups of structures or complexes and they can be used to supply vast regions by connecting power units to the national power grid. However, the process is well suited as a charging base for batteries or other electric storage devices. It can also be incorporated into vehicles to provide electric power while they are stationary or underway. This is particularly useful for electric powered vehicles. The process of the present application differs substantially from the prior art, as it facilitates the production of electric energy by the deliberate extraction of electrons from atoms and molecules of a gas, vapor, liquid, particulate solid, or any other form of matter that can be passed along the surface or through the electron extractor components, see reference numerals. The extracted electrons are collected and controlled or regulated and are available for distribution to various electric devices or storage components. Subject to the implementation, the electric energy could be moved to an inverter where it would be converted to the desired form. It is an energy efficient process for the extraction and capture of electrons for the production of electricity with positive atomic or molecular ions as byproducts. These results are accomplished by the forcible extraction of electrons from the object particles by electrically charged particles in a strong electric field. The process is superior to any other intended for the extraction and capture of electrons with the production of positive ions because it not only simplifies every implementation or utilization, but it also speeds the operation, allowing a continuous stream or beam of particles to be so manipulated. After ionization, the particles of the stream can then be confined in a coherent beam or restricted to a magnetic enclosure or by other confinement methods, expelled to the atmosphere, another environment or to ground, or modified into useful molecules. Additionally, the process of the present application demonstrates its superiority to any other because it is extremely efficient, in that, once the system is fully charged thereafter it requires only an occasional replenishment of energy to sustain operation. This is an important feature for any utilization. It is known that when a parallel plate capacitor is charged and subsequently isolated, it can retain its effective electric charge for an extended period of many months or even many years without degradation. It follows that the positive and negative electric fields produced by such a capacitor will likewise persist for extended periods or until the capacitor is purposely discharged. Exposing the plates of a parallel plate capacitor to an electric potential difference will establish a charge upon them equal to the potential. This involves the removal of electrons from the atoms of one plate with the placement of those electrons onto the opposite plate. Consequently, one plate becomes positively charged due to the shortage of electrons and the other plate becomes negatively charged due to the surplus electrons. This is one of the principles by which the process of the present application functions. The embodiments contain a conductive component, the electron extractor, on to which a positive electric charge is placed, where one type as part 26bb is shown in FIG. 1A. A charged surface of the component is positioned to maximize exposure and contact with the atoms or molecules subject to ionization. These atoms and molecules whose electrons are to be extracted will be referred to as the object or target particles. The charged electron extractor component may be constructed of various conductive materials and in various geometrical configurations, sizes, shapes, arrangements, and quantities. The charged electron extractor component also takes the form of a grid, pane, or panel. Throughout this application the term “grid” will be used to represent a variety of extractor components as may comprise certain embodiments that include but are not limited to the use of screens, lattices, nets, webs, gridirons, gratings, trellises, grills, grids or similar components, or any combination thereof. And the term “pane” will be used to represent a variety of extractor components as may comprise certain additional embodiments that include but are not limited to the use of sectioned or perforated panels, sheets, foil, disks, bars, rods, shafts, tubes, cones, plates, panes or similar components, or any combination thereof. And the term “panel” will be used to represent a variety of extractor components as may comprise certain additional embodiments that include but are not limited to the use of an assembly of non-perforated, sheets, foil, disks, bars, rods, shafts, tubes, cones, plates, panes, or similar components or any combination thereof. The grid, pane, and panel type extractors are defined in greater detail below. The primary difference between the extractor types relates to the system of contact between the target particles and the extractor. The grid type consists of a conductive material containing mesh openings through which the particles pass. Whereas the pane type consists of a sheet of solid conductive material containing perforations through which the particles pass. And the panel type consists of an assembly of multiple individual non-perforated conductive sheets arranged with gaps in between where along the surface of which the particles pass. The primary objective is to bring the target particles into close proximity to the charged surfaces of the various extractor types and to enhance the probability of contact. Some extractor types as may be used within certain embodiments may be interchangeable, subject to the requirements of the implementation. The extractors may take many forms and can be manufactured from different conductive materials. The actual materials, geometrical configurations, sizes, shapes, arrangements, and quantities of all components of a system are determined by the specific utilization. Furthermore, the top and bottom of a grid or other extractor type may be shaped to conform to the shape of a negative or positive field plate. For example, if, as seen from an end view, the field plate, part 22 of FIG. 1A, is curved, the top of the grid, part 26bb of FIG. 1A, would match that contour. Multiple extractors are operated individually as a group or as many groups as are necessary, by which or through which the object atoms and molecules are directed. However, when single or multiple extractor components are part of an assembly containing a negative field plate or as applicable, include a positive field plate, they will be referred to collectively as the electron extraction unit (EEU) of a type subject to the embodiment or the specific implementation. A positive electric charge is placed upon the extractor, where specifically the applied charge is sufficient to influence the valance electrons within a percentage of the atoms of the conductive material. For example, 60 percent of the atoms are encouraged to give up one electron, whereby the resultant positive charges will distribute evenly throughout the surface of the material. However, a +1 or greater net charge per atom can also be placed on the material, indicating the removal of one or more valence electrons from each atom. The, now, positively charged atoms will attract and forcibly extract electrons from any atom or molecule that closely approaches or comes into contact with the grid, pane or panel material of the electron extractor component. Other embodiments may utilize a grid type extractor assembly with one grid to extract the first electron from the object particle, a second grid for the second electron and a third grid for the third electron, and so on. Each successive grid may have different opening sizes and shapes to facilitate the molecule as it passes from one to the other. Additional control is gained by placing differing levels of charge from one grid to the other. Also, a constantly varying or alternating charge on single or multiple grids could be applied subject to the requirements of an implementation or utilization. In another embodiment, the object atoms or molecules could be re-circulated through a single grid held at either a constant net charge or a varying net charge to facilitate the extraction of additional electrons. Summarizing the previous discussion, because the number of valance electrons is known and varies with different materials, within certain limits the net average charge per atom of the grid, pane or panel can be controlled. Referring specifically to the grid or pane type extractors, additional control is obtained by adjustment of the thickness of the material, type of material and the shape and opening dimensions of mesh or perforations in relation to the size of the object atom or molecule. Additional control is gained through adjustable aperture sizes in height, width and depth and with shapes adjusted to maximize results for specific object atoms or molecules. Further controls are obtained by controlling the angle of the grid face and the aperture openings relative to the direction of the target particle flow. One, two, or multi-dimensional angular control of the panel type, pane type or grid type extractor can be applied to substantially increase the probability of direct contact. Direct contact with the extractor material substantially increases the probability of extracting at least one electron from the object particle. The quantity of electrons and the ease with which they can be removed from an atom or molecule is subject to the particle's ionization potential. Moreover, by the strict control of the variables described herein, including the average net positive charge per atom on the electron extractor, selectively, one or more electrons can be extracted per target atom or molecule. This has far reaching consequences, as subsequently described. The required net positive charge is applied to the extractor by a strong negative electric field produced by the electric potential difference, just as that between the plates of a parallel plate capacitor powered by a power source. In other embodiments, a strong magnetic field will have a similar effect with respect to placing a net charge on the extractor material. Likewise, in another embodiment a combination of electric and magnetic fields can be applied for this purpose. In some embodiments the extractor assembly takes the place of one of the field plates of the capacitor, actually becoming the positive field plate, as in FIG. 1A. Once the capacitor field plates are fully charged and the valance electrons are expelled from the extractor material, thereafter the system requires only an occasional energy supplement to maintain the effectiveness of its operation. A close encounter or direct contact between the positively charged surface of the extractor and the neutral target atoms or molecules results in the forcible extraction and capture of their electrons, thus producing positive ions. The strong negative electric field established upon field plate 22 repels both the valence electrons of the grid atoms and those electrons captured by the grid atoms. This applies to other types of extractors. The negative electric field drives the electrons toward the positive component that simultaneously attracts. The electrons are thus expelled from the grid to locations to where their return can be restricted by a valve. In those locations, they are held to maintain the electric field or for additional manipulation or stored for later utilization as electric energy. The captured electrons can also be used in some applications to power certain devices directly. By controlling the quantity of positive charges within the extractor material, the size and shape of the openings, perforations or gaps and the thickness of the material, electrons can be forcibly extracted from a continuous stream of target particles, such as those that comprise air. As can be seen, the present process is innovative in the capture and collection of electrons for the production of electric energy, demonstrating its superiority to any prior art. The figures described above are for purposes of explanation of the process and are not drawn to any relative or absolute scale. Furthermore, the actual size, shape and design of the parts are not absolute but rather are subject to the implementation. 12 Power source 22 Negative field plate 24 Positive field plate 26aa Grid type extractor 26ab Second grid type extractor 26ac Third grid type extractor 26ag Grid type extractor assembly 26bb Grid type positive field plate 26bc Second grid type positive field plate 26bd Third grid type positive field plate 26bg Grid type positive field plate assembly 26cc Pane type extractor 26cb Pane type positive field plate 28a Panel type extractor 28b Panel type positive field plate 32 Valve assembly, represented by a diode 34 Valve assembly, represented by a diode 36 Valve assembly, represented by a diode 38 Valve assembly, represented by a diode 42 Charge collector 44 Ion diverter 46 Diverter charge plate 52 Charge control unit 62 Electric storage unit 72 Electric inverter unit In the figures that follow single function grid type, pane type and panel type extractor components are shown, where in the previous groups of figures, dual function extractor components were shown. The single function extractor components are physically independent from the positive terminal of the power source 12. The basic operation of FIG. 5C is as that described in FIG. 6A. As the power source 12 is activated, equal to the electric potential difference, valance electrons are detached from the atoms of the positive field plate 24 establishing a positive electric field there, and the electrons are transferred to the negative field plate 22 establishing a negative electric field there. Furthermore the valance electrons of the grid atoms are repelled by the negative field plate 22 and are attracted to the positive field plate 24, while at the same time they are attracted by the positive charge established on the collector 42. From the perspective shown, the target atoms and molecules of air or other gas are guided to the backside of grid 26aa and exit through the front as ions. While the target particles are passing through the grid 26aa, the close encounter or contact with the atoms of the grid material results in the extraction and capture of one or more electrons. Remaining valance electrons and the subsequent captured electrons are in turn repelled from the grid atoms by the strong negative electric field imposed by the field plate 22. These electrons are at the same time attracted towards the positive field plate 24 by the strong positive electric field placed there. Simultaneously the strong positive charge on the positive terminal of the collector 42 attracts both the valance and captured electrons from the grid 26aa to the negative terminal. The collector 42 represents any quantity that may be required by an implementation. As can be seen, valve 32 allows electrons to move from the positive field plate 24 and prevents their return. And valve 38 allows electrons to be deposited on the negative field plate 22 and prevents their escape and return to the power source 12. Valve 34 allows electrons to move from the grid 26aa to the negative side of the collector 42 and prevents their return. Valve 36 allows electrons to move from the positive terminal of the collector 42 and the diverter charge plate, part 46, and prevents their return. As shown here the control unit 52 distributes the collected energy to the inverter unit 72. However, an electric storage unit 62 has been added to increase the capacity. Although a single electric storage unit 62 is shown, it is representative of a group consisting of any quantity that may be required by an implementation. The inverter 72 converts the electric energy into the required form. For example, direct current (DC) can be converted to a required voltage and frequency such as 120V alternating current (AC) at 60 Hz. The energy is thus immediately available for use in a variety of applications. As can be seen, by maintaining the respective electric charge upon the negative field plate 22, the positive field plate 24 and the positive side of the collector 42 and placing the embodiment in an environment containing air or other gas that moves through the grid, a continuous supply of electric energy is produced, collected and made ready for use in a variety of systems. Additionally, the process functions as described above in FIGS. 1A, 6A and 4C. Although the descriptions above show many alternative embodiments, they should not be interpreted as to limit the scope of the embodiments, as they are representations of only a small number of potential embodiments. Furthermore, the primary components of any embodiment may be arranged differently and the components may take on different values, shapes, configurations and specifications from that shown or described herein. Simplicity, efficiency, adaptability, versatility, low energy consumption, and high productivity are just some of the terms that describe the advantages of the process of the present application. It is an innovative process for the production of electric energy and the production of positive ions. It can operate continuously 24 hours per day without interruption provided the proper electric charge is maintained upon each of the three primary components that include the negative field plate, the dual function extractor or positive field plate and the positive side of the collector. Through the process, electric energy can be supplied individually to each structure or demand location making them independent from any other energy source. It can be scaled to accommodate the electric power requirements of many implementations and utilizations that include portable units and units fitted to stationary or portable appliances, devices, apparatus and vehicles. Accordingly, the reader will see that the process of the present application is superior for the extraction and capture of electrons from atoms and molecules, the production of positive ions and electric energy.
053533143	abstract	An electric field plasma pump includes a toroidal ring bias electrode (56) positioned near the divertor strike point of a poloidal divertor of a tokamak (20), or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix (40) of the poloidal divertor contacts the ring electrode (56), which then also acts as a divertor plate. A plenum (54) or other duct near the electrode (56) includes an entrance aperture open to receive electrically-driven plasma. The electrode (56) is insulated laterally with insulators (63,64), one of which (64) is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode (56) and a vacuum vessel wall (22), with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E.times.B/B.sup.2 drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable.
	abstract	In the dimension measurement of a circuit pattern using a scanning electron microscope (SEM), in order to make it possible to automatically image desired evaluation points (EPs) on a sample, and automatically measure the circuit pattern formed at the evaluation points, according to the present invention, in the dimension measurement of a circuit pattern using a scanning electron microscope (SEM), it is arranged that coordinate data of the EP and design data of the circuit pattern including the EP are used as an input, creation of a dimension measurement cursor for measuring the pattern existing in the EP and selection or setting of the dimension measurement method are automatically performed based on the EP coordinate data and the design data to automatically create a recipe, and automatic imaging/measurement is performed using the recipe.
047643056	abstract	The invention relates to a process for the conditioning of radioactive or toxic waste in epoxy resins and a polymerizable mixture with two liquid constituents usable in this process.. This process consists of incorporating the waste into a polymerizable mixture incorporating at least one epoxy resin, pitch and at least one epoxy resin hardener and allowing the thus obtained mixture to harden.. Generally the mixture comprises at least 50% by pitch weight and can be used for treating radioactive waste constituted by large objects and organic liquids.
	summary
	claims	1. A magnetic jack control element drive mechanism, comprising:an upper coil assembly comprising a first sleeve configured to coaxially wrap a control element drive shaft, a first coil, and a first coil housing, wherein the first coil housing is connected to the first sleeve with a first reception portion of the first sleeve receiving the first coil between the first sleeve and the first coil housing;a lower coil assembly located under the upper coil assembly, the lower coil assembly comprising a second sleeve configured to coaxially wrap the control element drive shaft, a second coil, and a second coil housing, wherein the second coil housing is connected to the second sleeve with a second reception portion of the second sleeve receiving the second coil between the second sleeve and the second coil housing the second coil housing;a connecting screw which connects the first coil housing of the upper coil assembly with the second coil housing of the lower coil assembly;a support tube which extends downward from the lower coil assembly, wherein the first and second sleeves, the connecting screw, and the support tube have an identical inner diameter;a motor assembly which is located between the control element drive shaft, and the first and second sleeves, wherein the motor assembly comprises at least one stationary magnet, at least one lifting magnet, at least one latch magnet, and at least one latch arm; andan anti-separation cap configured to prevent upward movement of the motor assembly, the cap having a through-hole penetrated by the control element drive shaft, and being connected to a top portion of the upper coil assembly,wherein, a top end of the connecting screw is interlocked with a first insert groove which is located on a lower end of the first coil housing,a bottom end of the connecting screw is interlocked with a second insert groove which is located on an upper end of the second coil housing,an upper end of the support tube is interlocked with a support groove which is located on a bottom end of the second coil housing, andthe first and second sleeves, the connecting screw, and the support tube together constitute a pipe. 2. The magnetic jack control element drive mechanism of claim 1, wherein each of the first coil and the second coil is a mineral-insulated coil. 3. The magnetic jack control element drive mechanism of claim 1, wherein each of the first and second coil housings is formed of martensitic stainless steel, and each of the first and second sleeves is formed of martensitic stainless steel, austenitic stainless steel, or nickel alloy. 4. The magnetic jack control element drive mechanism of claim 1, further comprising a first space between the at least one stationary magnet and the at least one lifting magnet, and a second space between the at least one lifting magnet and the at least one latch magnet. 5. The magnetic jack control element drive mechanism of claim 4, wherein the first and second spaces are configured to provide room for movement for the at least one lifting magnet and the at least one latch magnet when the first coil generates magnetic force.
	claims	1. A method for treating an article that includes a radioactive material, the method including the steps of:(a) loading the article into a containment area defined in a treatment vessel;(b) while the article is being held in the containment area, tilting the treatment vessel from a loading position to a treatment position to place the article in contact with a liquid reactant metal in the treatment vessel to decompose the radioactive material in the article into radioactive material decomposition constituents dispersed in the liquid reactant metal;(c) producing a storage mixture including the radioactive material decomposition constituents dispersed in the liquid reactant metal together with radioactive emission control materials, the radioactive emission control materials being present in the storage mixture in an effective ratio with radioactive material decomposition constituents in the storage mixture to limit radiation emissions from the storage mixture; and(d) cooling the storage mixture in one or more molds to form a solidified storage product for the radioactive material decomposition constituents. 2. The method of claim 1 wherein the article comprises one or more pieces of a nuclear reactor fuel rod or one or more whole fuel rods. 3. The method of claim 1 further including the step of encapsulating the solidified storage product in a radiation shielding material. 4. The method of claim 1 wherein the step of producing the storage mixture includes combining radioactive emission control materials and the liquid reactant metal after placing the article in contact with the liquid reactant metal. 5. The method of claim 1 wherein the step of producing the storage mixture includes combining the radioactive emission control materials and the liquid reactant metal prior to placing the article in contact with the liquid reactant metal. 6. The method of claim 1 further including the step of pouring the storage mixture from the treatment vessel into one or more molds. 7. A method of treating a target material in a liquid reactant metal, the method including the steps of:(a) loading a target material into a containment area defined in a treatment vessel and holding the target material in the containment area, the containment area being defined within a boundary separating the containment area from the remainder of the volume of the treatment vessel;(b) with the target material held in the containment area, tilting the treatment vessel to a treatment position to change a level of a liquid reactant metal in the treatment vessel so as to place at least a portion of the containment area below the liquid reactant metal in the treatment vessel and thereby place the target material in contact with the liquid reactant metal; and(c) removing reaction products from the treatment vessel while the liquid reactant metal is maintained in a liquid state. 8. A method of treating a target material in a liquid reactant metal, the method including the steps of:(a) containing a volume of liquid reactant metal in a treatment vessel;(b) while containing the liquid reactant metal in the treatment vessel, loading a target material into a position in the treatment vessel in which the target material is contained out of contact with the liquid reactant metal in the treatment vessel;(c) tilting the treatment vessel to place the target material in contact with the liquid reactant metal; and(d) removing reaction products from the treatment vessel. 9. The method of claim 8 wherein the step of loading the target material into the treatment vessel includes loading the target material into a containment area defined in the treatment vessel. 10. The method of claim 9 further including the step of tilting the treatment vessel to a loading position and maintaining the treatment vessel in the loading position during the step of loading the target material into the containment area, the containment area residing above the level of the liquid reactant metal in the treatment vessel when the treatment vessel is in the loading position. 11. The method of claim 10 wherein the step of tilting the treatment vessel to place the target material in contact with the liquid reactant metal comprises tilting the treatment vessel to a treatment position in which the containment area resides below the level of the liquid reactant metal in the treatment vessel. 12. The method of claim 8 wherein the step of removing reaction products from the treatment vessel includes pouring liquid reactant metal and reaction products entrained in the liquid reactant metal from the treatment vessel.
	claims	1. An apparatus for obtaining a long-length x-ray image of a subject, comprising:an x-ray source;a first sensor configured to sense x-ray transmission from the x-ray source and to generate a first signal that indicates termination of x-ray emission from the x-ray source;a digital radiography detector that is energizable to generate image data after receiving x-ray emission from the x-ray source;a detector transport apparatus actuable in response to the first signal to translate the digital radiography detector from at least a first detector position to a second detector position for generating image data at each detector position;a processor in communication with the digital radiography detector for obtaining the image data of the subject that is generated from the detector;a movable mask operatively associated with the x-ray source and providing an aperture that directs x-rays from the x-ray source toward the subject for capturing a plurality of separate images of the subject on the digital radiography detector;a second sensor operatively associated with the movable mask to produce a second signal in response to detecting X-ray emission from the source; anda mask translation control responsive to the second signal for moving the movable mask from at least a first mask position to a second mask position for exposing an area of the subject. 2. The apparatus of claim 1 wherein the movable mask is coupled to a collimator of the x-ray source. 3. The apparatus of claim 1 wherein the movable mask is removably or permanently coupled to the x-ray source. 4. The apparatus of claim 1 wherein the detector transport apparatus comprises one or more of a spring, a servo motor, and a solenoid. 5. The apparatus of claim 1 wherein the mask translation control further comprises one or more of a spring, a servo motor, and a solenoid. 6. The apparatus of claim 1 wherein the mask translation control uses gravity for moving the mask. 7. The apparatus of claim 1 wherein the first sensor is an audio sensor or a photosensor. 8. The apparatus of claim 1 wherein the first sensor or the second sensor is an audio sensor or a photosensor. 9. The apparatus of claim 1 wherein the detector transport apparatus actuable in response to the first signal to translate the digital radiography detector and the mask translation control responsive to the second signal for moving the mask operate independently from each other. 10. The apparatus of claim 1 where a single controller does not control both the detector transport apparatus and the mask translation control. 11. The apparatus of claim 1 further comprising an indicator that is actuable to indicate that the digital radiography detector is ready for exposure. 12. The apparatus of claim 1 further comprising an indicator that is actuable to indicate that the digital radiography detector is ready for translation to the second detector position. 13. A method for obtaining a long-length x-ray image of a subject, comprising:positioning a digital radiography detector at a first detector position relative to the subject;positioning a movable mask to a first mask position relative to an x-ray source that directs exposure energy onto the digital radiography detector at the first detector position;energizing the x-ray source to expose the subject at the first detector position;obtaining a first signal from a first sensor that indicates termination of x-ray emission from the x-ray source;obtaining image data from the digital radiography detector at the first detector position;obtaining a second signal from a second sensor that indicates termination of x-ray emission from the x-ray source;asynchronously actuating a detector transport apparatus to translate the digital radiography detector from the first detector position to a second detector position for generating image data responsive to the first signal and a mask transport apparatus to translate the movable mask to a second mask position that directs exposure energy onto the digital radiography detector responsive to the second signal;energizing the x-ray source to expose the subject at the second detector position;obtaining a third signal from the first sensor that indicates termination of x-ray emission from the x-ray source;obtaining image data from the digital radiography detector at the second detector position; andcombining the image data from at least the first and second detector positions to form the long-length x-ray image. 14. The method of claim 13 further comprising manually setting up at least the first and second detector positions and storing the first and second positions in a memory. 15. The method of claim 13 wherein actuating the detector transport apparatus comprises energizing a motor or a solenoid. 16. The method of claim 13 wherein actuating the mask transport apparatus comprises energizing a motor or a solenoid. 17. An apparatus for obtaining a long-length x-ray image of a subject, comprising:an x-ray source;a first sensor that generates a first signal that indicates x-ray emission from the x-ray source;a digital radiography detector that is energizable to generate image data after receiving x-ray emission from the x-ray source;a detector transport apparatus actuable in accordance with the first signal to translate the digital radiography detector from at least a first detector position to a second detector position for generating image data at each detector position;a processor in communication with the digital radiography detector for obtaining the image data of the subject generated from the detector;a movable mask operatively associated with the x-ray source and providing an aperture that directs x-rays from the x-ray source toward the subject for capturing a plurality of separate images of the subject on the digital radiography detector;a second sensor operatively associated with the movable mask for producing a second signal in response to termination of X-ray emission from the source; anda mask translation control responsive to the second signal for moving the mask from at least a first mask position to a second mask position for exposing an area of the subject. 18. The apparatus of claim 17 wherein the first or second sensor is an audio sensor or a photosensor. 19. The apparatus of claim 17 wherein the detector transport apparatus comprises one or more of a spring, a servo motor, and a solenoid.
059096543	description	DETAILED DESCRIPTION Preferred embodiments of the present invention will now be described with continued reference to the drawings. The sulphur or chloride containing waste is subjected to pyrolysis at a temperature of no more than 700.degree. C., and preferably no more than 600.degree. C., to form a gas which contains organic sulphur or chloride compounds and a solid pyrolysis residue which contains radioactive material from the waste. The pyrolysis residue (ash) 6 is fed to a steam reformer 61 to gasify the residual carbon. Significant volume reduction and overall cost savings to the waste generator can be realized by gasifying the carbon content of the solid pyrolysis residue (ash) 6 to CO.sub.2 or CO. The final waste residue 7 can be reduced from the volume of the pyrolysis residue 6 by a factor of 2 to 5 times. The steam reformer 61 is preferably a fluid bed or rotary contact design. An optional compressing device may be added for further reducing the residue volume. The final waste residue 7 from the steam reformer 61 is pelletized and packaged 62. The residue pellet package 62 is decontaminated 63 and gamma scanned 64 through standard procedures known in the art. The residue pellet package 62 is stored 65 until prepared for final shipment 66 for burial. Gases from both the pyrolysis reactor 20 and the steam reformer 61 are preferably mixed and oxidized (combusted) in a submerged bed heater (afterburner) 30 operating at a preferred temperature of 1800-2200.degree. F. The present invention overcomes many of the problems of sulfur and nitrogen oxide formation during standard combustion of ion exchange media. The pyrolysis step utilizes substoichiometric quantities of air which forms a reducing atmosphere. In such reducing conditions sulfur forms H.sub.2 S, or in the presence of Fe it readily forms FeS and/or FeS.sub.2. The nitrogen components remain as N.sub.2, and minimal NO.sub.x. Although described herein as utilizing a two stage process of pyrolysis-combustion, the steam reformer process of the present invention may also be used with other treatment process, such as the two stage pyrolysis-pyrolysis process described in copending U.S. application Ser. No. 08/403,758. Heat recovered from the submerged bed heater 30 may be used to heat the process facility and/or to provide heat to dry the resin as described below or to evaporate water from dilute solutions to provide concentration. The gases from the submerged bed heater are quickly reduced in temperature by a submerged bed evaporator (quencher). The use of a submerged bed evaporator allows the water temperature to be closely controlled to provide zero liquid discharge from the facility by vaporizing all of the process water. The vaporized process water is then passed out the exhaust stack as gaseous discharge. The submerged bed evaporator also serves as a scrubber to remove acid gases from the offgas stream. The acid gases are converted to salts which are concentrated to 5-15% wt. solids by the removal of water to offgas. This avoids the need for a separate concentrator unit. The offgas stream is fed to a standard, commercially-available, fiber bed scrubber 51 to remove residual acid gases and particulates. The fiber bed scrubber 51 preferably provides a low pressure drop of 5 to 10 inches of water and preferably removes more than 99% of particulates and entrained mists. The pyrolysis step involves subjecting the solid waste to pyrolysis at a temperature of no more than 700.degree. C., and preferably not more than 600.degree. C. The term "pyrolysis" is used herein in its conventional sense, i.e. chemical decomposition or breakdown of a substance by the action of heat and without any real supply of oxygen or at least so little oxygen supply that no real combustion is effected. The pyrolysis thereby leads to breaking down of the carbonaceous waste to a relatively fluffy pyrolysis residue which can be drawn off from the bottom of the pyrolysis reactor employed and can thereafter be imparted a significantly smaller volume by gasifying the carbon content of the residue, and, optionally compression. Additionally, by keeping the temperatures no higher than those recited above, practically speaking all of the radioactive materials, in particular .sup.134 Cs and .sup.137 Cs, are retained in the pyrolysis residue and therefore measures and consequent costs to remove additional radioactivity can be minimized. Any fly ash formed can, however, be removed from the resulting gas in a per se known manner, preferably in a ceramic or metal filter in the pyrolysis reactor. In this way, the radioactive material in the fly ash caught in the filter can be returned to the pyrolysis residue. In the practice of the invention, it has proven possible in this fashion to attain very high retention of the radioactivity in the pyrolysis residue. In this regard, trials carried out on ion exchange media from a nuclear power station show a retention of almost 10.sup.6 :1, i.e. the decontamination factor ("DF") is of the order 10.sup.6. Aside from said radioactive material, the pyrolysis residue contains carbon and possibly iron compounds such as iron oxides and iron sulphides. Trials in this connection, show the retention of sulphur, in the pyrolysis residue to be >90%. No immediately critical lower limit is apparent for the pyrolysis in the pyrolysis reactor 20 but rather this limit is dictated, if anything, by effectiveness and/or cost. However, for practical purposes, a lower limit can generally be set at 400.degree. C. and therefore a preferred embodiment of the method of the invention involves the pyrolysis unit 20 being operated at a temperature in the range 400-700.degree. C., preferably 400-600.degree. C., especially 450-600.degree. C., and most preferably 450-550.degree. C. Additionally, as the method of the invention as a whole has proven to be extremely effective both as regards the solids content and the evolved cases, the pyrolysis stage is preferably carried out without any catalyst for the breakdown of the carbon compounds in the waste which, of course, means that the method of the invention is very cost effective as the catalyst costs in comparable contexts often represent a large part of the total costs. The pyrolysis stage can be carried out in per se known fashion as regards the type of pyrolysis reactor 20, e.g. in a fluidised bed, but in the overall set-up of the method in the context of the invention, "flash pyrolysis" has proven to give exceptionally good results. The expression flash pyrolysis is used herein in its conventional sense, i.e. with a relatively rapid, flow-through of material. In other words, it is a matter of a short residence time, normally less than 30 seconds and even more usually a significantly shorter time, e.g. less than 15 seconds. An especially preferred "flash pyrolysis" is carried out in a gravity or flash reactor for which a suitable residence time can be 3-15 seconds, even better 4-10 seconds and most preferred 5-8 seconds such as around 6 seconds. Suitable residence times are, however, easily determined by the man skilled in the art in each individual case. An important additional consideration found is that the flash pyrolysis process of resins for about 5-8 seconds can be used under high throughput production operations. The flash pyrolysis of resins will convert the external surface of small resin particles. Subsequent residence times in the bottom of the pyractor vessel 20 for about 0.1-1 hours will complete the pyrolysis conversion. The particles have been found not to stick or adhere to each other because any incomplete flash pyrolysis that occurs in the drop zone is sufficient to convert the outer surface, thus preventing adhesion between the hot particles which accumulate in the bottom of the pyractor vessel 20. The pyractor 20 is a gravity drop vessel and may utilize either multiple drop tubes or a single large diameter drop. In the present case, it will be understood that "solid waste" does not concern a solution of the material in question. It need not however necessarily concern a dry material but also material with a certain degree of moisture content, e.g. up to 50%, usually 10-30% such as is often the case when using ion exchange media. However, for flash pyrolysis, for example, it can be convenient to condition the material prior to pyrolysis, which means a certain degree of drying and optionally, comminution. In this regard, a material in powder form has proven to give very good results in the initial pyrolysis step. The ion exchange medium is fed from a cask/liner 10 to a resin storage container 11. The ion exchange medium 5 is preferably ground in a grinder 12, centrifuged 13, and dried in a dryer/feeder 14, prior to being fed into the pyrolysis vessel 20. Excess gas/vapor from the dryer/feeder 14 is fed to condenser 15. Water from condenser 15 is pumped 44 from container 41 to ion exchange unit 42. The ionized water is stored in container 43 and pumped 45 with tap water to the submerged bed evaporator 31. Fine iron powder, preferably Fe.sub.2 O.sub.3, may be added with the resin feed to the pyrolysis vessel 20. The Cl from chloride containing waste combines with the iron in the pyrolysis vessel 20 to form FeCl.sub.2, which is an inert, high melting point inorganic solid which will remain in the carbon rich residue. Sulfur containing wastes effectively combine with the iron powder to form FeS and FeS.sub.2 compounds. The fine iron oxide powder will also collect on the ceramic or metal filters exhausting the offgas from the pyrolysis vessel 20 to the submerged bed heater 30. The iron powder effectively converts H.sub.2 S to FeS and SO.sub.2 to H.sub.2 S and to FeS. The gas, which is formed during the pyrolysis step, contains decomposition products from the organic waste referred to as "tars". These tars principally contain pure hydrocarbons and water vapor, and organic sulphur or chloride compounds and amines when the waste is of the nitrogen and sulphur or chloride containing ion exchange media type. The gas is separated from the pyrolysis residue and subjected to oxidation (combustion) in a second stage 30. When the gases from the pyrolysis vessel 20 and the steam reformer 61 contain tar products and water, a preferred embodiment of the method of the invention will subject the gas, prior to being fed to the submerged bed heater, to condensation conditions such that tar products therein condense out and are separated before the gas is conducted to said submerged bed heater 30. In this context, "tar products" will be understood to include carbonaceous compounds which are, of course, in gaseous form after pyrolysis in the first stage but which drop out in the form of a more or less viscous tar mixed with water. The condensate can be separated by fractionated condensation (not shown) into a low viscosity tar of high calorific value, water and a viscous sulphur-rich tar. If sulphur oxides, especially SO.sub.2, are present in the cases emanating from the pyrolysis vessel 20, they must be attended to in an appropriate manner bearing in mind the strict requirements which now apply to the release of sulphur oxides and other sulphur compounds. As noted above, this may be directly attained by feeding offgases to a demister/fiber bed scrubber 51. The demisted gases are pumped 52 to a HEPA filter 53 and then vented through a standard ventilation stack 54 with radiation monitors. One alternate method for attending to any sulfur oxides present in the offgas is to expose the offgas from the submerged bed evaporator 31 to a bed (not shown) of a solid reductant under reducing conditions so that the sulphur oxides are reduced, principally to hydrogen sulfide and carbon disulfide. Carbon, in particular, has proven to work extremely well as a reductant in relation to the method of the invention. Additionally, carbon results in the sort of end products, especially carbon dioxide, which are harmless and in principle can be released direct to the atmosphere. The temperature for the reduction is selected by one skilled in the art in this field in such a fashion that the sought after reactions are attained. The reduction is carried out at a temperature in the range 700.degree. C. to 900.degree. C., the approximately 800.degree. C. temperature level probably lying near the optimum. Alternately, one may add air to the reformer, allowing operation to as low as 375.degree. C. The reduction bed additionally leads to a reduction in nitrogen oxides in the event that these are present in the gas after the pyrolysis steps. In the event that a high temperature filter of the carbonaceous filter type or similar is utilized for filtering out the soot in the reformer offgas, this filter can be regarded as a reduction means for use in this optional reduction step of the invention. Finally, the gas may optionally be exposed to a bed (not shown) of a sulphide-forming metal under conditions in which the remaining sulphur compounds form metal sulphides with said metal. In this context, it is the gas from the prior optional reduction step, if present, or the gas from the submerged fuel evaporator 31. In each case it is primarily a matter of transforming hydrogen sulfide to metal sulfide. Preferably, iron is used as sulfide-forming metal as iron is a cheap material and results in a harmless product, principally in the form of the iron disulfide, pyrite. Other metals, however, are also conceivable of which nickel can be mentioned as an example. The temperature for this optional step is also selected by the man skilled in the art in this field so that the sought after reactions are attained. An especially preferred temperature range, however, is 400-600.degree. C. the approximately 500.degree. C. level being especially suitable in many cases. As has been touched upon earlier, both the solid end-product and the gaseous end-products of the method of the invention are amenable to handling. The resulting ash, for example, is thus particularly suitable for post-treatment in the form of simple compression, where the practice of the invention has proven that the volume can be reduced by as much as up to 75%. Furthermore, the resulting gases are rich in light organic compounds which implies a gas with a high heat content which can be burnt. Additionally, the sort of gases being referred to are non-injurious to the surroundings, e.g. carbon dioxide, gaseous nitrogen, gaseous hydrogen and water vapor, and therefore the method of the invention, as a whole, represents unparalleled advantages in relation to the known technique. In order that the method should proceed in an effective fashion and especially in order that the release of radioactive or unpleasant or dangerous gases through system leakage should be avoided, with consequent risks to working personnel, a further preferred embodiment involves carrying out the method under a certain degree of vacuum or negative pressure, conveniently by arranging a suction pump 52 or gas evacuation pump downstream of the demister/fiber bed scrubber 51. The following especially preferred embodiments of the apparatus can be mentioned. Preferably, the pyrolysis reactor 20 is a gravity reactor. An optional condenser (not shown) for the condensation of tar products in the gas may be located prior the submerged bed heater 30. A metal or ceramic filter (not shown) for the separation of any fly ash from the gas is preferably located in the pyrolysis reactor 20 and the steam reforming vessel 61. Optionally, a compactor (not shown) may be included for compression of the carbon reduced pyrolysis residue 7 resulting from the steam reformer 61. It is understood that various other modifications will be apparent to, and can be readily made by, those skilled in the art without departing from the scope and spirit of the present invention. Accordingly, it is not intended that the scope of the claims be limited to the description or illustrations set forth herein, but rather that the claims be construed as encompassing all features of patentable novelty that reside in the present invention, including all features that would be treated as equivalents by those skilled in the art.
044951426	abstract	The nuclear reactor container of a boiling water reactor has a dry well and a pressure suppression chamber. The level of the radioactivity in the cooling water filling the pressure suppression chamber is measured by a liquid radiation monitor. An iodine monitor measures a level of the radioactivity of the iodine in the space above the surface of cooling water in the pressure suppression chamber, while a noble gas monitor measures a level of the radioactivity of noble gas in the same space. Outputs from the liquid radiation monitor, the iodine monitor and the noble gas monitor are delivered to an accident judging device which makes judgement as to occurrence of perforation of fuel rods and melt down of fuel rods in the event of a Loss Of Coolant Accident (LOCA), the result of which is displayed at a display device.
	abstract	Compositions and processes for forming radiopaque polymeric articles are disclosed. In one embodiment, radiation inspection apparatuses and methods are then used to determine the presence and attributes of such radiopaque polymeric articles. A radiopaque polymeric article of the present invention can be created by mixing a radiopaque material, such as barium, bismuth, tungsten or their compounds, with a powdered polymer, pelletized polymer or liquid solution, emulsion or suspension of a polymer in solvent or water. In addition to creating radiation detectable objects, the radiopaque polymeric materials of the present invention can be used to create radiation protective articles, such as radiation protective garments and bomb containment vessels. Enhanced radiation protection can also be achieved through the use of nano-materials. The principals of the present invention can be used to provide protection against other types of hazards, including fire, chemical, biological and projectile hazards.
	description	This disclosure relates to devices that can be used by patients during medical procedures and in particular radiation procedures. The device has particular application as a shield in breast cancer radiotherapy though it is not intended to be limited to this treatment only. One in eight women will develop breast cancer in their lifetime and it is the most common cancer in women. It is recommended that radiotherapy treatment is delivered after initial surgery for breast cancer to substantially reduce the risk of site specific relapse. However, during breast cancer treatment using radiotherapy, the other breast (the contralateral breast) receives radiation dose as an unwanted side effect of the treatment. The association between low dose from peripheral ionizing radiation and the risk for secondary cancer has attracted interest specifically for the long-term surviving patients. Specifically, concerns regarding oncogenesis and second cancer induction are realized and invoke the need for ALARA (As Low As Reasonably Achievable) principles to be followed. During radiation therapy, regardless of the treatment technique, the surrounding normal tissue outside the treated area inevitably receives some amount of radiation dose. Such dose outside the geometric boundaries of the treatment fields is known as peripheral dose. There are three main sources of peripheral dose: (a) leakage through the treatment collimation (x-rays); (b) scattered radiation from the secondary collimators and beam modifiers such as the MultiLeaf Collimator (MLC), physical wedges (x-rays and electrons); and (c) internal scatter originating in the patient (x-rays). It has been shown that peripheral doses can be as large as 20% of maximum dose for normally incident beams and that these values can increase with oblique angle of incidence. To minimize radiation doses delivered to the contralateral breast, lung, and heart, some patients can be treated with a prone technique. If a supine treatment is used, to reduce contralateral breast dose, different types of shielding devices, and delivery techniques have been used. These include mobile high-density lead shields placed between the treatment machine and the patient. Other devices used were tissue-density superflab material laid over the patient's contralateral breast. Although these methods did reduce contralateral breast dose, they presented technical difficulties in their usage. Mobile lead shields need to be placed appropriately between the patient and the treatment head of the linear accelerator (linac). Such techniques are not very efficient since they demand precise positioning alignments. They also suffer from not being able to be shaped around the treatment field edges. Superflab bolus can also reduce skin and subcutaneous dose but it requires at least 10 mm thickness of bolus material to provide sufficient attenuation. This process may also introduce misalignment errors near the edge of the treatment fields. What is required is an improved shielding method and device. To provide patient shielding of non-treatment areas bordering a treatment zone of the patient during radiation therapy, a shield device may be located on the patient. The shield device has a plurality of interconnected and overlapping elements, e.g. in a scale maille arrangement, that forms a conformal sheet that can be laid over the shielded portion of the patient, e.g. over the contralateral breast during breast cancer treatment. The edge of the scale maille sheet is substantially configurable and can be made to conform to the field edge of the treatment zone on the patient. In one aspect of the disclosure, there is provided a method for providing shielding to a patient during a radiation treatment. The method may include locating at least one shield device over at least one portion of the patient to be shielded. The at least one shield device may include a plurality of overlapping and interconnected shield elements that form a sheet including at least one substantially configurable edge. The method may include substantially aligning at least one configurable edge of the at least one shield device with at least one field edge of a treatment zone of the patient to leave the treatment zone exposed, and subjecting the patient to a radiation treatment. In one aspect of the disclosure, there is provided a device for use in radiation therapy of a patient, the device including a plurality of overlapping and interconnected shield elements that form a sheet including at least one configurable edge, wherein the at least one configurable edge is able to be configured to substantially conform to a field edge of a radiation treatment zone of a patient during a radiotherapy procedure. In FIG. 1, there is shown a portion of a device or shield 10 during manufacture and assembly. The device 10 includes a sheet 12 including a plurality of individual shield elements 14, such as plates or scales, that are interconnected and arranged in overlapping patterns to form the sheet. The individual plates may each include one or more holes 16 that allow attachment means to join adjacent elements to each other. In one embodiment, the attachment means may be rings 18, e.g. metal rings, though other attachment means may be contemplated including non-metal rings, threads, rivets, etc. In general, the sheet may be referred to as a scale maille sheet and many methods for forming scale maille are known. While scale maille refers to specific arrangements of the plates, other interlocking plate or scale arrangements may be contemplated. For example, other plate arrangements may be generally referred to as lamellar armor. At times throughout the present specification and in the Figures, the device 10 may be referred to using the Applicant's proprietary term Smart Armour. FIG. 2 shows a more fully assembled form of the sheet of FIG. 1 that can be used to reduce contralateral breast dose during radiation. In one particular embodiment, the device 10 is made from 12 mm×22 mm×0.6 mm thick copper scales, interwoven together to form a scale maille design as shown in FIGS. 2a and 2b. Conventional scale maille weaving techniques may be employed to create the scale maille. This utilizes the use of 7 mm diameter jumper rings linked together and the 0.6 mm thick copper scales threaded over the jumper rings through a 2 mm diameter hole located at the top of each copper scale. By interweaving the scale maille pattern, the 0.6 mm thick copper scales overlap producing a 1.2 mm thick copper shield at all points. The underside of the scale maille is shown in FIG. 2b. As is shown in FIG. 2b, the jumper rings may be of copper, though other metals or non-metals may similarly be used. In the embodiment of FIG. 1, a typical scale, i.e. within the body of the sheet, is linked to four adjacent scales, being the four scales diagonally above and below the respective scale, in the orientation depicted in FIG. 1. The upper portion of the scale underlies the scales above, while the lower portion overlies the scales below. Other overlapping and interconnecting configurations are possible and are considered within the scope of the present disclosure. In one embodiment, the device 10 has dimensions of 30 cm×30 cm×0.3 cm thick. This is considered sufficient to cover a typical contralateral breast. In other embodiments, the device 10 may be of any suitable size for use in shielding any required part of the body during other radiation therapy treatments. The shield elements 14 are not rigidly locked to each other but rather, the means by which the shield elements 14 are interconnected allows for a degree of movement between adjacent elements. Within the body of the sheet, this degree of movement allows the sheet to conform to various shapes, in particular various shapes of the body. At the edge of the sheet, the shield elements are sufficiently displaceable to allow the shape of the edge to be configured to various shapes, including straight edges, angles, and curves. As will be made apparent below, this degree of configurability has particular advantages for allowing the shield to be used at a non-straight edge of a radiation treatment zone of a patient, while allowing the treatment zone to remain exposed. A typical radiation therapy device is depicted in FIG. 3. FIG. 3 shows a patient 30 lying supine on a treatment table 32. A linear accelerator head (linac) 34 is disposed above the patient. For most breast radiation treatments, the linear accelerator 34 will be located to one side of the patient to provide a tangential radiation dose. As can be seen from FIG. 3. the patient may be subject to radiation from primary photos, secondary photons and electrons. Portions of the patient outside of a treatment zone may receive some of this radiation, known as a peripheral dose. In breast cancer treatment, for example, the linac 34 tends to be located on the contralateral breast (untreated breast) side of the patient so that the radiation is incident at an angle to the patient, known as tangential treatment. The contralateral breast can therefore be subject to a significant peripheral dose of radiation. During radiation therapy for breast cancer treatment and the like, the shield device 10 can be draped over the contralateral breast region, ensuring that the shield does not interfere with any entry fields. This would cause increases in skin dose due to build up dose effects. The shield conforms to the breast shape and provides protection during treatment. The shield does not need to be present during simulation or CT as it does not affect treatment dose and treatment should not occur through the device. The design of the shield allows the copper scales to overlap thus providing an approximate 1.2 mm thickness of copper over the entire region of the shield. The design allows the shield 10 to conform to the shape of the contralateral breast providing substantial coverage and shielding. The shield 10 has a configurable edge formed by multiple plates 14 and thus can be shaped to follow the irregular field edges required by typical cancer treatments for radiotherapy. The shield 10 can be handled safely as it is made from copper, and is thus nontoxic and can be easy for radiation therapy workers to use on patients. Shielding properties of various metals have been studied in the peripheral region of 6 MV x-ray beams produced by a Varian 6EX linear accelerator (Varian Medical Systems, Palo Alto, Calif., USA). The materials evaluated were 1.0 mm thick aluminum, 1.0 mm copper, and 1.0 mm lead sheets. Dose measurements were performed in RMI solid water (RMI, Middleton, Wis., USA) using an Attix model 449 parallel plate ionization chamber (RMI, Middleton Wis., USA) at depths of 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, and 15 mm. Measurements were made 5 cm away from the edge of the primary field which was a 10 cm×20 cm field size at 100 cm source to surface distance (SSD). Results were compared to measured percentage dose at the same peripheral position for an open field with no metal shielding in place. The results were normalized to 100% at the depth of maximum dose at the central axis of the primary radiation field (depth of 15 mm). The measurements were repeated 6 times for uncertainty analysis. Errors were calculated as 2 standard deviations of the mean for all measurements taken at each measurement point. These errors combine both type A and type B errors associated with uncertainty in set up as well as deviations in measurement accuracy. Errors are expressed as the square root of the sum of the squares of each error in relation to measurements made and is expressed by:δR=√[(δx)2+(δy)2+(δx)2] where δR is the total error, and δx, δy, and δz represent each component of measured uncertainty. Dose measurements were also made on the shielding characteristics of a scale maille designed peripheral dose shield. To evaluate contralateral breast shielding, an ART anthropomorphic phantom 40, as shown in FIG. 4, was positioned on a Varian 21EX linear accelerator and treated with a conventional 10 cm×20 cm asymmetric parallel opposed field size using a medial and tangent beam configuration with 6 MV x-ray beams. Skin doses were measured using a Gafchromic EBT3 film (Ashland Inc, New Jersey, USA) from 5 cm inside the medial edge of the medial beam and across the contralateral breast (covered by shield 10 in FIG. 5). Gafchromic films have been shown to be suitable for accurate skin dosimetry. Again, the measurements were repeated six times for reproducibility and uncertainty analysis. The doses were normalized to 100% delivered dose at the midpoint position in the treated breast. The skin dose results were compared to percentage dose results delivered without the shield 10 in position. The measured dose represented the sum of radiation dose delivered from both the medial and lateral beams. To evaluate the shield using different types of clinical treatments, five clinical plans from different patient treatments were delivered to the ART phantom and skin dose assessed with and without the shield. The five patient treatments delivered included, patient one, using enhanced dynamic wedge fields, patients two and three, using field in field techniques, and patients four and five, using a hybrid intensity modulated radiation therapy (IMRT) technique. Physical wedges were not used for patient treatments and thus were not evaluated. Results for skin dose were measured using the same techniques as the open field measurements. To perform the irradiations, the patient plans were transferred to the ART phantom CT dataset for planning and treatment delivery. It is acknowledged that the plans would not be optimized due to differences in anatomy; however, this work would highlight differences in contralateral breast skin dose delivered, with and without the shields. FIG. 5 shows the results measured for attenuation of the radiation beam when the different metals are used to attenuate radiation in the beams peripheral region and compared to no shield results. Results were measured at depths ranging from 0 mm (at the skin surface) down to 15 mm, well beyond the subcutaneous tissue region. As can be seen in this configuration, at the surface when no shield was in place, approximately 13% of maximum dose was delivered. This was reduced to 9.5% for aluminum, 4.5% for copper and 7.2% for lead. A comparison of these values in dose reductions for three metals is shown in Table 1. For example, at 5 mm depth, the aluminum provides a 22.5% reduction in dose, whereas the copper and lead achieve 49% and 56.7% reductions, respectively. TABLE 1Peripheral skin dose reduction with metal shields.Dose reduction achievable with various metals.Depth (mm)AluminumCopperLead024.6 ± 4.262.2 ± 4.641.2 ± 3.8127.6 ± 3.763.6 ± 5.367.6 ± 4.3227.5 ± 4.760.3 ± 3.566.8 ± 4.4324.6 ± 3.954.3 ± 3.363.9 ± 5.0522.5 ± 4.549.0 ± 4.256.7 ± 4.410 9.4 ± 2.238.1 ± 2.126.3 ± 3.015 2.6 ± 3.6 6.6 ± 3.313.2 ± 4.2 FIG. 6 shows a dose profile measured across the chest wall of the anthropomorphic phantom, with and without the shield in place. The results are measured at an equivalent depth of 0.125 mm which is the effective point of measurement of EBT3 film. The results are normalized to 100% at the midpoint in the treated breast. In this example, the skin dose within the treatment field is similar with and without the shield being approximately 30-35% of maximum. However, in the peripheral region (from 50 mm distance onwards), the skin dose has been substantially reduced by the presence of the SMART Armor being reduced from as high as 16% down to approximately 4%. This represents an up to 75% reduction in dose achievable in the contralateral breast region with the use of the SMART Armor. FIG. 7 shows the results for percentage dose reductions achievable across the chest wall of the anthropomorphic phantom. As can be seen, variations in contralateral breast dose with and without the SMART Armor range from approximately 60% to 80% in all five cases studied. In all cases, substantial reductions in skin dose are measured whether the treatment technique utilized enhanced dynamic wedges, field in field techniques, or hybrid IMRT dose delivery. Dose delivered to the peripheral skin and subcutaneous regions during clinical radiotherapy is mainly caused by incident electron contamination from the entry beams. This contamination originates from production in the air column and the linear accelerator head. As such, substantial attenuation of this dose can be achieved by peripheral shielding using high-density materials. Results as discussed herein highlight the dose reduction achievable. Of interest is the significant reductions achieved with 1.0 mm of copper which reduced dose levels to below 5% at all depths. This value decreased to just below 4% by 15 mm depth and the majority of the dose remaining at all depths is expected to be from internal radiation scatter and high-energy x-ray penetration which was capable of transmission through the linear accelerator tungsten jaws. As the reductions in dose were achieved by removal of electron contamination, dose from posterior beams will not negligibly reduce for the contralateral breast. As such, 1.0 mm of copper material could be considered a useful shielding thickness if dose to peripheral regions were required to be reduced. This is the case for the contralateral breast during breast cancer treatment. Interestingly, lead showed a unique and reproducibly higher dose level directly under its surface compared to copper producing an average 7.6% dose compared to 4.8%. At every other depth beyond the surface, the peripheral measured dose was less for lead than for copper. Our assumptions are that the lead is producing a small quantity of low energy radiation on the exit side which deposits a larger degree of dose at the phantom surface. This does not occur for copper. Aluminum has a much lower density than copper or lead, and thus provides less radiation shielding properties at all depths. As the skin is a radiation sensitive organ, these findings make copper a better suited radiation shield than lead for peripheral regions when 6 MV x-rays are used for radiotherapy treatment. As copper is a strong but malleable material it also lends itself well to be used to construct flexible and maneuverable shielding using a scale maille design. The scale maille device can conform to the shape of the contralateral breast phantom with a configurable edge that can conform to the irregular shaped treatment field edge as well as providing substantial reductions in delivered peripheral dose. As copper is a nontoxic material and lasts a long time without perishing and/or oxidation, it is well suited for clinical use when a shield is required for reducing the contralateral breast dose. Reductions of up to 80% from original values were achieved with the shield for standard open field tangential treatments. When standard clinical treatments were evaluated including enhanced dynamic wedges, field in field and hybrid IMRT techniques, the dose reductions achieved using the shield remained high. In the five cases studied, the values for percentage dose reduction ranged from 60% up to 80% across the contralateral breast region. As such, the shield as herein described can provide substantial contralateral breast shielding during common supine breast irradiation techniques. The shield when used is only draped over the contralateral breast region and is not placed within the primary breast treatment field. No distinguishable change in primary breast dose was measured or expected with the use of the shield. The shield 10, due to its weaved design, is easy to use clinically and takes approximately 30 seconds to align on the anthropomorphic phantom. Clinically this may take longer; however, any small increase in time for set up is warranted due to the substantial reductions in contralateral breast dose achieved. High-density materials, such as copper, can provide substantial shielding effects in radiotherapy cancer treatment in the peripheral regions of megavoltage x-ray beams. Copper has been shown to be superior to lead as a choice of shielding material due to its ability to reduce skin dose to a lower level. Copper was also found to be a useful choice of material to create a scale maille style shield which can be used to provide protection to skin and subcutaneous tissue in peripheral regions during radiotherapy treatment. This is especially useful in treatment of breast cancer where dose to the contralateral breast can be reduced by up to 80% of original values. While copper has been shown to provide enhanced results over some other materials such as lead, there may be applications for these and other materials in various embodiments. For example, many high density metals and alloys may be suitable, including, without limitation brass, stainless steel, lead, tin, tungsten, silver and gold. FIGS. 1, 2a and 2b show a shield formed in a diamond pattern. The diamond pattern shield is shown in situ on the anthropomorphic phantom 40 in FIG. 4. In a diamond pattern, the scales are arranged in rows 13 (FIG. 1) that are at an angle, in particular a 45 degree angle, to the edge 15 of the device 10. A diamond pattern is considered the simplest form of scale maille pattern to manufacture. In the embodiment shown, each scale or plate is generally leaf or tear-drop shaped having a longitudinal axis that extends perpendicular to the row. The plate is generally convex on the outer side (exposed side) of the shield with the main curve extending across the longitudinal axis, i.e. perpendicular thereto. The particular scale shape of scale is shown for illustrative purposes only and is not intended to be limiting. Other scale designs may be utilized with equal effect. An alternative embodiment of a shield is depicted in front view in FIG. 8 and rear view in FIG. 9. In this embodiment, the shield 80 is formed in a rectangular pattern in which the rows 83 are generally parallel and perpendicular to the edges 85, 87 of the shield. FIG. 10 shows a dummy 90 simulating a patient that is to receive radiation treatment. The patient 90 includes the breast to be treated 92 and the contralateral breast 94. A field edge 96 that marks a boundary of the treatment region of the patient is shown. As depicted in FIG. 10, for tangential treatment, the linac would typically be located to the left of the patient in the orientation of FIG. 10. The patient would thus receive radiation incident in the general direction depicted by arrow 98. An issue with the diamond pattern as herein described is that, as shown in FIG. 4, it can be difficult to conform the edge of the shield 10 to the field edge 96. In addition, because the field edge is generally sagittal, the scale rows are generally located at an angle to the incident radiation, which may not provide the optimum shielding. When the rectangular pattern shield 80 of FIGS. 8 and 9 is placed over the contralateral breast 94 (FIG. 11), and the edge of shield is conformed to the substantially sagittal field edge 96, the rows of scales run generally perpendicular to the incident radiation with the plates more directly facing the incident radiation. Thus the radiation is less likely to penetrate any gaps between the scales. As shown in FIG. 8, the scales along the lower edge 89 may be trimmed to form a straighter edge. This edge 89 may be used as the edge that is aligned and conformed to the field edge of the treatment region of the patient. Though, while each scale may have a generally straight edge, on the whole, the scales are sufficiently displaceable that the edge 89 remains sufficient configurable to form non-straight shapes that can tailor to match the typical edge of the treatment region. While specific embodiments relating to the radiotherapy treatment of breast cancer has been described herein, it will be apparent to the person skilled in the art that the shield devices and methods for their use may extend to many other forms of shielding in patient treatments. The advantages of the shield device as herein described include that the shield has a conformal arrangement that can contour to many parts of the human body with a substantially configurable edge that can be conformed to a field edge of a treatment region, thereby allowing the peripheral dose received into non-treatment areas to be minimized. Further, while the treatment methods described herein show a single shield device being utilized at one edge of a treatment zone, the person skilled in the art will recognize that multiple shields may be deployed around multiple field treatment zone edges. In this way, the shields may be used to at least partially define the treatment zone that will be left exposed and thus subject to a dose of radiation during radiotherapy. It will be understood by the person skilled in the art that terms of orientation such as top, bottom, front, back, left, right, inner, outer, etc. are used herein with reference to the drawings in order to provide a clear and concise description. Such terms are not intended to limit the examples and embodiments in any manner and the scope of the disclosure as defined herein will encompass other possible orientations of the components as will be perceived by the person skilled in the art. Although embodiments of the present invention have been illustrated in the accompanied drawings and described in the foregoing description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by any claims that follow.
049884743	abstract	Process and holding component for repair of a nuclear reactor fuel assembly spacer support. The holding component is formed from a metal strip, on the free ends of which are introduced elastic projections. After removal of the damaged crosspiece, a holding component partly embracing the fuel rod is locked into a slot of a spacer support by means of its projections.
	abstract	The present invention relates generally to a process for a pressurized water reactor. The pressurized water reactor includes a primary circuit and a reactor core. The process includes adding a sufficient amount of an organic compound to coolant water passing through the primary circuit of the pressurized water reactor. The organic compound includes elements of carbon and hydrogen for producing elemental carbon.
	claims	1. An x-ray analysis apparatus for illuminating a sample spot with an x-ray beam, comprising;an x-ray tube having a source spot from which a diverging x-ray beam is produced having a characteristic first energy, and bremsstrahlung energy;a first x-ray optic for receiving the diverging x-ray beam and directing the beam toward the sample spot, the first x-ray optic monochromating the beam;a second x-ray optic for receiving the diverging x-ray beam and directing the beam toward the sample spot, the second x-ray optic monochromating the beam to a second energy; andwherein the source spot requires alignment along a transmission axis passing through the sample spot, the apparatus further comprising:a first tubular housing section to which the x-ray tube is attached along a first axis thereof such that the source spot coincides with the first axis, the first housing section further including mating surfaces aligned to the first axis;a second tubular housing section having a second axis coinciding with the transmission axis, and mating surfaces aligned to the second axis; andthe first and second x-ray optics attached to the second housing section for receiving the diverging x-ray beam and directing the beam toward the sample spot, the first and second optics requiring alignment along the transmission axis;the first housing section and the second housing section being matable along their respective mating surfaces to thereby align the first and second axes with the transmission axis, thereby aligning source spot, x-ray optics, and sample spot. 2. The apparatus of claim 1, wherein the first x-ray optic monochromates characteristic energy from the source spot and the second x-ray optic monochromates bremsstrahlung energy from the source spot. 3. The apparatus of claim 1, wherein the x-ray optics are curved diffracting optics, for receiving the diverging x-ray beam from the x-ray tube and focusing the beam at the sample spot. 4. The apparatus of claim 3, wherein the x-ray optics are focusing monochromating optics. 5. The apparatus of claim 4, wherein the focusing onochromatic optics are doubly curved crystal optics or doubly curved multi-layer optics. 6. The apparatus of claim 1, further comprising a third x-ray optic for receiving the diverging x-ray beam and directing the beam toward the sample spot, the third x-ray optic monochromating bremsstrahlung energy from the source spot to a third energy. 7. The apparatus of claim 1, wherein each optic is attached to the second housing section for receiving the diverging x-ray beam and directing a respective portion of the beam toward the sample spot, and requiring alignment along the transmission axis, mounted along a surface of the second housing section, and separated from the transmission axis. 8. The apparatus of claim 1, further comprising a third housing section, the third housing section including an aperture along the transmission axis through which the x-ray beam passes when illuminating the sample spot, the second housing section and third housing section being matable along respective mating surfaces to thereby align the aperture with the transmission axis and therefore the sample spot, the apparatus further comprising an x-ray detector mounted to the third housing section in alignment with the sample spot. 9. The apparatus of claim 1, wherein the first and second housing sections are tubular in shape, and the mating surfaces of the first and second housing sections comprise surface portions in contact with each other upon attachment of the first and second tubular housing sections. 10. The apparatus of claim 9, wherein the x-ray optics are focusing monochromating optics. 11. The apparatus of claim 10, wherein focusing monochromatic optics are doubly curved crystal optics or doubly curved multi-layer optics, mounted along a surface of the second housing section, and separated from the second axis. 12. An x-ray analysis apparatus for illuminating a sample spot with an x-ray beam, comprising:an x-ray tube having a source spot from which a diverging x-ray beam is produced, the source spot requiring alignment along a transmission axis passing through the sample spot;a first housing section to which the x-ray tube is attached along a first axis thereof, the first housing section including adjustable mounting features for adjustably mounting the x-ray tube therein such that the source spot coincides with the first axis, the first housing section further including mating surfaces aligned to the first axis;a second housing section having a second axis coinciding with the transmission axis, and mating surfaces aligned to the second axis; andfirst and second, different x-ray optics attached to the second housing section for receiving the diverging x-ray beam and directing the beam toward the sample spot at different respective energies, the first and second x-ray optics requiring alignment along the transmission axis;the first housing section and second housing section being ma able along their respective mating surfaces to thereby align the first and second axes with the transmission axis, thereby aligning the source spot, x-ray optics, and sample spot. 13. The apparatus of claim 12, wherein the first optic monochromates characteristic energy from the source spot and the second x-ray optic monochromates bremsstrahlung energy from the source spot. 14. The apparatus of claim 12, wherein the x-ray optics are curved diffracting optics, for receiving the diverging x-ray beam from the x-ray tube and focusing the beam at the sample spot. 15. The apparatus of claim 14, wherein the x-ray optics are focusing monochromating optics. 16. The apparatus of claim 15, wherein the focusing monochromatic optics are doubly curved crystal optics or doubly curved multi-layer optics. 17. The apparatus of claim 12, further comprising a third x-ray optic for receiving the diverging x-ray beam and directing the beam toward the sample spot, the third x-ray optic monochromating bremsstrahlung energy from the source spot to a third energy. 18. The apparatus of claim 12, wherein the second housing section is tubular in shape, with the second axis running longitudinally therein. 19. The apparatus of claim 12, wherein the x-ray tube is tubular in shape, having its source spot at one end thereof. 20. The apparatus of claim 12, wherein the first and second housing sections are tubular in shape, and the mating surfaces of the first and second housing sections comprise surface portions in contact with each other upon attachment of the first and second tubular housing sections. 21. The apparatus of claim 12, further comprising a carriage for mounting each x-ray optic to the second housing section to receive the diverging x-ray beam, the carriages mountable either directly or indirectly to the second housing section, such that an active surface of x-ray optics are aligned along, and positioned a desired distance from, the transmission axis. 22. The apparatus of claim 21, wherein a surface of the second housing section to which the carriages are mounted are fabricated such that the at least one x-ray optic is positioned the desired distance from the transmission axis.
06278756&	claims	1. A method of making an electrochemical corrosion potential sensor electrode comprising the steps of: providing a sensor tip; connecting a conductor to the sensor tip; providing an insulating member around the conductor; providing a connecting member around the conductor; providing a sleeve which fits over the insulating member, a portion of the connecting member, and a portion of the sensor tip; forming inner threads on the sleeve; forming outer threads on at least one of the sensor tip and the connecting member; and engaging the inner threads with the outer threads. 2. The method of claim 1, further comprising the step of forming the insulating member of sapphire. 3. The method of claim 2, further comprising the step of forming the connecting member of alloy 42. 4. The method of claim 3, further comprising the step of brazing the insulating member to at least one of the sensor tip and the connecting member.
	claims	1. A spacer grid for a nuclear fuel assembly having a plurality of spacer grids which are regularly and transversely arranged along the nuclear fuel assembly to support a plurality of longitudinal fuel rods while maintaining a desired pitch of the fuel rods, comprising: a plurality of first inner straps, each having a rectangular-shaped body and integrated at its upper edge with a plurality of double deflected vanes which are polygonal shaped, projecting upwardly, bent twice toward fuel rod in a cell, and capable of guiding an axial flow of coolant around the fuel rod thereby generating swirl flow, each of the first inner straps also having a plurality of vertical slits at positions between the double deflected vanes, said vertical slits extending from an upper edge of each first inner strap to the middle of said strap and being spaced at an interval equal to the pitch of the fuel rods; and a plurality of second inner straps, each having a rectangular-shaped body and integrated at its upper edge with a plurality of double deflected vanes which are polygonal shaped, projecting upwardly, bent twice toward fuel rod in a cell, and capable of guiding an axial flow of coolant around the fuel rod thereby generating swirl flow, each of the second inner straps also having a plurality of vertical slits at positions between the double deflected vanes, said vertical slits extending from the lower edge to the middle of said second inner strap and being spaced at an interval equal to the pitch of the fuel rods, whereby said first and second inner straps are interlaced at right angles at corresponding vertical slits, thereby forming a plurality of square cells capable of receiving the fuel rods, wherein each of said double deflected vanes comprises: a swirl flow inducing vane having an inclined edge and an asymmetric triangular shape, said swirl flow inducing vane being integrated with the upper edge of an associated one of the first and second inner straps and being deflected in a direction toward an associated fuel rod at a first acute angle with respect to a plane of the associated inner strap; and a main vane integrally extending upward from the inclined edge of the swirl flow inducing vane and deflected in the direction toward the associated fuel rod at a second acute angle with respect to a plane of the swirl flow inducing vane, said main vane having a curved edge adjacent the associated fuel rod. 2. The spacer grid according to claim 1 , wherein a pair of double deflected vanes disposed on either side of each of the vertical slits of the first and second inner straps are substantially rotationally symmetrical about a center line of the vertical slit. claim 1 3. The spacer grid according to claim 1 , wherein a pair of double deflected vanes are positioned within each of the square cells, such that said pair of vanes face each other and are deflected toward the fuel rod inside the square cell so as to generate swirl flow about the axis of the fuel rod in the cell. claim 1 4. The spacer grid according to claim 1 , wherein the second acute angle is larger than the first acute angle. claim 1 5. The spacer grid according to claim 1 , wherein the width of lower portion of said swirl flow inducing vane is substantially equal to the distances between welding nuggets formed at each intersection of the first and second inner straps. claim 1 6. The spacer grid according to claim 1 , wherein the curved edge maintains a constant distance from the surface of the associated fuel rod. claim 1
	abstract	A concrete storage module (26) is adapted to slideably receive a cylindrical canister assembly (12) therein. Heat dissipation fins (62) and a tubular heat shield (96) are disposed within the module to help dissipate heat emitted from the nuclear fuel assemblies stored in the canister to air flowing through the module. The canister assembly (12) is composed of a basket assembly (70) constructed from multi-layer structural plates disposed in cross-cross or egg carton configuration. A single port tool (106) is provided for draining water from the canister (12) and replacing the drain water with make-up gas. The single port tool is mounted in the cover (100) of the canister and is in fluid flow communication with the interior of the canister.
	abstract	An in-core instrumentation system for a reactor module includes 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 is housed within a lower head that is removably attached to the reactor pressure vessel, and lower ends of the in-core instruments are located within the reactor core. The in-core instruments are configured such that the lower ends are concurrently removed from the reactor core as a result of removing the lower head from the reactor pressure vessel.
	description	This application claims priority of U.S. Provisional Patent Application Ser. No. 60/628,334, filed Nov. 15, 2004, the entire content of which is incorporated herein by reference. The invention relates to engine diagnostic apparatus and methods, in particular, to engine misfire detection. Engine misfire leads to degradation in engine performance. Furthermore, it can lead to unburned fuel leaving the engine in exhaust gases. A catalytic converter is often provided to reduce the amount of pollutants in exhaust gases, and part of the function of the catalytic converter is to induce combustion of unburned fuels on a surface of the catalytic converter. Hence, if appreciable amounts of unburned fuel are present in the exhaust gases, the catalytic converter will overheat, and can be rapidly destroyed. Hence, it would be desirable to provide improved engine misfire detection methods and corresponding apparatus. A method of detecting an engine malfunction such as a misfire includes determining engine speed values at each of a plurality of measurement angular positions, heterodyning the engine speed values with sine and cosine functions indexed in the angular domain, and passing the heterodyned values through a low pass filter. An apparatus for detecting an engine malfunction, such as a misfire, includes an engine speed analyzer, a multiplier, and a low pass filter. In a conventional four-stroke multi-cylinder engine, any given cylinder fires once every two revolutions of the engine. A single cylinder misfire in any multi-cylinder engine causes a strong half-order engine speed variation (also called a torsional velocity signature), which can be detected as part of an improved engine management system. Hence, the half order (and sometimes the first order) torsional vibration magnitude is a strong indicator of engine misfire. First order analysis can be useful for engines with certain type of ignition systems where cylinders are paired on a common ignition coil, as a pair of cylinders misfiring 360 degrees apart generates a strong first order signature. In this application, terms such as “first-order,” “half-order,” etc. relate to torsional vibrations at multiples of engine speed. A first-order signal repeats once per engine revolution, and a half-order signal repeats once per two engine revolutions. The term “engine speed” refers to the rotational speed of an engine crank shaft, or equivalent rotating engine member, which can be measured in revolutions per minute (rpm) or other convenient unit. The term “speed sensor” is used to refer to a sensor providing a signal correlated with engine speed. The term “angle” refers to rotation angles of the engine. One engine revolution corresponds to 360 degrees, and, for example, an angular interval or angle of 90 degrees corresponds to one quarter of a revolution. Improved detection of half-order engine speed variations allows a single cylinder misfire to be rapidly detected, allowing engine management steps to be taken so as to reduce damage to a catalytic converter. Discrete angular domain sampling offers major computational advantages in comparison to discrete time sampling. Further, using a first order IIR (infinite impulse response) filter instead of the numerical integration used in conventional convolution algorithms offers further computational advantages with very little loss of accuracy. In modern automobiles, it is common for a coil to feed opposed pairs of cylinders. A misfire in opposing cylinder pairs in an engine with an even number of cylinders and four or more cylinders causes a strong first-order engine speed variation. Hence, a coil failure can be detected from detection of a first-order variation. A vehicle engine commonly has a speed sensor, typically providing a train of pulses as the engine rotates, with a predetermined number of pulses per revolution. In a common configuration, a toothed wheel rotates with the engine, and a pulse is produced every tooth. Hence, if there are N teeth on the rotating wheel, one revolution of the engine generates N pulses. In examples of the present invention, in order to detect both half-order and first order signals, three or more measurements of engine speed per engine revolution are detected. As a consequence of the Nyquist sampling theorem, the minimum number of engine speed values determined per engine revolution is preferably greater than twice the order of interest. If there are more than the minimum needed pulses per revolution, the pulse train can be passed through a pulse frequency divider (also called a pulse prescaler) so as to provide a reduced number of pulses every revolution. For half-order signals, at least three engine speed values per two revolutions are used. The elapsed time between two successive pulses within a train of pulses can be divided into a constant to obtain an engine speed value. In other words, S=C/T, where S is the engine speed value, T is the elapsed time between pulses, and C is a constant related to the angle between adjacent teeth and the units used for the engine speed. For example, engine speed can be measured in revolutions per minute (rpm), radians per second, or other convenient units. However, for misfire detection according to the present invention, the units used are not important as the misfire detection is sensitive to relative changes in the engine speed. Hence, a new engine speed value can be obtained every time a new pulse is received from the speed sensor, by determining the engine speed from the elapsed time from the previous pulse. If no division of the pulse train is used, a single pulse is obtained from every tooth on the rotating wheel. However, the number of teeth per sample can be varied, without affecting the successful operation of the misfire detection. A pulse prescaler can be used to divide the pulse train by some factor, if desired. An engine speed analyzer receives a train of pulses from, for example, a flywheel having a number of teeth distributed around the periphery of the flywheel, and calculates an engine speed value as proportional to the reciprocal of the time between the pulses. A faster pulse train corresponds to a reduced time between successive pulses, and hence corresponds to a higher engine speed. The engine speed analyzer may effectively function as a pulse train to frequency converter. Frequency components within the successively determined engine speed values can be found by multiplying, or heterodyning, the engine speed values with a sinusoid (or sine function) having a frequency of the order of interest, then determining a non-zero offset in the resulting multiplied signal. For example, the sinusoid may have a period of 360 crankshaft degrees for first order detection or 720 crankshaft degrees for half order detection. The d.c. component (offset) can then be found by passing the multiplied signal through a low pass filter. For a two-stroke engine, first order engine speed variations are generally of interest. Engine speed variations at the effective combustion frequency may be determined. FIG. 1 shows a schematic of an apparatus according to an example of the present invention comprising a speed sensor 10, providing pulses at periodic angular intervals as the engine rotates, an engine speed analyzer 12, a heterodyne stage (for example, a multiplier) 14, a sine value provider 16, and a low pass filter 18. In this example, the speed sensor 10 provides a stream of pulses, there being a fixed number of pulses (N) per engine revolution. N is greater than or equal to three, as discussed above, for first order detection. The engine speed analyzer receives the train of pulses, and provides engine speed values based on the time interval between successive pulses. The sine value provider 16 provides values of a sine function, the sine function having a period equal to half, one, or two engine revolutions for half, first or second order, respectively. The sine function values are correlated with the angular positions at which speed values are determined by the engine speed analyzer. To reduce computational burdens, a pre-computed table of sine functions can be used in the manner of a look-up table. One advantage of this approach over conventional approaches is that the heterodyne stage (or multiplier) effectively works in the angular domain. Conventional systems normally use a time domain sampling, where the engine speed is determined every fixed period of time. The current approach is more computationally efficient, as the sampling of engine speed increases as the engine speed increases, and the engine speed can be recalculated at the time a new pulse is received by the engine speed analyzer 12. The multiplied signal, from heterodyne stage (or multiplier) 14, is provided to the low pass filter 18. This may use an algorithm such as described below, approximating a convolution function where the low-pass filter is substituted for an integrator and sampling is done in the angular instead of the time domain. In the example of a perfectly running engine, the engine speed is constant, hence the multiplication by the heterodyne stage 14 provides a perfect sinusoid to the low pass filter. In this example the low pass filter provides an output of zero, as the sinusoid averages to zero, and does not have any offset component. Half-order engine speed variations are detected by multiplying engine speed values by a half-order sinusoid and sending the multiplied signal to a low pass filter. The multiplied signal is a sinusoid distorted by engine speed variations, and these distortions cause the low-passed multiplied signal to be non-zero. Hence, by multiplying the engine speed values by a half-order sinusoid, and determining a long term average of the resulting multiplied signal, a single engine misfire can be detected. Engine speed values are multiplied by sine and cosine (or imaginary and real) values, and the magnitude of engine speed variations is determined from the low-passed multiplied sine and cosine signals (as described elsewhere, for example in relation to FIG. 4), and compared with a threshold value. An improved approach with computational efficiency advantages is described below. FIG. 2 shows a schematic of an apparatus according to an example of the present invention, in which a pulse train from a speed sensor 40 is received by engine speed analyzer 41, and engine speed values provided by the engine speed analyzer to both first heterodyne stage (or first multiplier) 42 and second heterodyne stage (or second multiplier) 50. The first heterodyne stage 42 multiplies the engine speed value by a sine value, provided by sine value provider 44, and passes the sine multiplied signal (or imaginary component of the engine speed variation) to first low pass filter 46. The second heterodyne stage 50 multiplies the engine speed value by a cosine value, provided by cosine value provider 52, and passes the cosine multiplied signal (or real component of engine speed variation) to the second low pass filter 54. Unlike conventional systems, the sine and cosine tables are indexed in the angular domain, as a function of crank shaft angle. Engine speed sampling is also performed in the angular domain, for example at periodic angular intervals as the crank shaft rotates. The first low-passed signal provided by first low pass filter 46, and second low-passed signal provided by second low pass filter 54, are combined in magnitude calculator 56. The magnitude calculator 56 determines the magnitude of engine speed variations from a combination of squared values of first and second low-passed values, as discussed below in relation to FIG. 4. In the schematic of FIG. 2, half-order signatures can be detected, if the sine function and cosine function both have a period equal to two revolutions or 720 crankshaft degrees. The magnitude of the combined signal is used to detect the presence of a single cylinder misfire. The magnitude of the combined signal is compared with a threshold value, and if the magnitude is greater than the threshold value, engine management steps are taken to either correct the misfire, protect the catalytic converter from destruction, or otherwise improve engine performance. Engine management steps may include providing a signal indicating a problem, shutting down the engine, or other steps. FIG. 3 shows a schematic of a misfire detection method. Box 60 corresponds to calculation of a low pass filtered signal correlated with engine speed variations at a half (or first) order. Box 62 corresponds to a comparison of the signal with a threshold value. If the signal is greater than the threshold, box 66 corresponds to detection of a misfire, with associated engine management steps such as disconnecting a misfiring cylinder. If the signal is less than the threshold value, box 64 corresponds to no detection of a misfire, and correspondingly taking no engine management steps. Determination of the threshold value, and possible engine management steps, are described in more detail below. FIG. 4 shows a schematic of a method according to the present invention, which in this example is achieved using a software program executable by a processor within an apparatus according to the present invention. Box 80 corresponds to initializing the apparatus. Box 82 corresponds to obtaining the number of pulses per engine revolution from initialization data, N, as received from a speed sensor. Box 84 corresponds to checking that N is greater than or equal to a minimum value. For example, three speed samples per engine revolution may be used for first order engine speed fluctuation detection. Box 86 corresponds to providing a prompt for a correction if N is less than the required minimum value. Box 88 corresponds to generating sine and cosine tables of size 2N each. For computational simplicity, the tables can be fixed point, signed, and short sized in format. However, this is not essential. A short loop, for n=0 to n=2N−1, can be used to provide pre-calculated values of sine and cosine for each N for use in a lookup table. A tooth event prescaler can be adjusted to give a desired number of tooth events per revolution. This is an optional step, and the number of tooth events per revolution can be set to any convenient number greater than or equal to that needed. Experiments were performed with four tooth events per revolution, corresponding to four determinations of engine speed per revolution. For example, a loop of the following form can be used: FOR n=0 to n=2N−1 Sine [n]=:(short)(sin(n/(2N)2PI)32767.0) Cos [n]=:(short)(cos(n/(2N)2PI)32767.0) NEXT Box 90 corresponds to enabling a pulse event capture, corresponding to receiving of a pulse from the speed sensor. At this point, illustrated by the circle labeled ‘A’, the algorithm described below in relation to FIG. 5, or similar algorithm, is executed, returning values related to engine speed variations at the order(s) of interest, such as those discussed below in relation to Box 110 of FIG. 5. Box 92 corresponds to a host request order update. This relates to an optional implementation, in which parallel processors, or threads on a single processor system, are used. A first processor or thread monitors data in real time, and a second processor or thread computes magnitude of speed variations, detects misfires, and requests updated data at intervals from the first processor. The update can be asynchronous with crank shaft position. For example, the second processor can execute a software program as described in relation to FIG. 4, and the first processor can execute a software program including an algorithm as described in relation to FIG. 5 below. Box 93 corresponds to determination of the real (cosine multiplied) and imaginary (sine multiplied) components of the engine speed variation at the order of interest. Box 94 corresponds to computation of the magnitude of the engine speed variation at an order of interest. For example, the magnitude of the half-order speed variation can be calculated as the square root of the sum of the sine multiplied signal squared and the cosine multiplied signal squared, both signals being squared after being passed through a low pass filter. For example: Magnitude[order #]=(Real[order #]2+Img[order #]2)0.5 Here, the terms real and imaginary are used for vector components of the engine speed variation, and these correspond to cosine and sine multiplied signals, respectively. The term “order #” relates to speed variations at a particular order number. The final square root is optional, as a comparison can be made between the sum of squared components with a threshold value that is related to the square of an engine speed variation. The mean square, root mean square, or similar, may also be determined and compared with a threshold value. The magnitude of any order engine speed variation of interest, for example half-order, first-order signal, or any other order, can be determined. The computation of magnitude can be a continuous process which results in one new real and imaginary component for each order computed every time velocity is sampled. The real and imaginary component values may be read asynchronously to the sampling process and combined to compute a magnitude for each order separately or in combination. Box 96 corresponds to returning the results to the host. At this point if the magnitudes are greater than predetermined thresholds, engine management adjustments can be carried out. Misfire is detected by comparing the magnitude of each order to a threshold (for example, a predetermined constant), and if the magnitude is greater than the threshold the misfire is suspected. FIG. 5 is a schematic illustrating the operation of an algorithm, the algorithm being triggered by receipt of a pulse from the speed sensor. Box 100 corresponds to receipt of a pulse from a speed sensor. This may also be referred to as a tooth event, as the speed sensor, in many examples, may comprise a toothed wheel providing a pulse each time a tooth passes a tooth sensor. Box 102 corresponds to operation of the engine speed analyzer, in this case carried out by software running on a processor. The engine speed is calculated by dividing a constant by the elapsed time since the last tooth event. One approach is: Count=Read Tooth Count since last interrupt from hardware Time=Read Elasped Time in microseconds since the last interrupt from hardware Speed=(601.0e6)Count/(NTime). In this example, the Count variable is effectively a prescaling factor. In some examples, a speed sensor provides an excess number of pulses per engine revolution, and a pulse prescaler divides the frequency of the unscaled pulse train by a value equal to count to provide a desired number of pulses per revolution. Box 104 corresponds to passing the speed signal through a high pass filter. In one example, the following approach was used: HiPassSpeed[n]=Speed[n]−LowPassSpeed[n] and LowPassSpeed[n]=(Speed[n]−LowPassSpeed[n−1])/k+LowPassSpeed[n−1] where n is the sample index, and k is an IIR (infinite impulse response) filter coefficient. A value of 32 was used for k. IR equations are updated once per speed sample and their bandwidth is proportional to engine speed. The low pass filter output was used only to monitor correct operation of the algorithm, and can be discarded. Fo−3db=Speed(rad/sec)4/(2pi) (samples/revolution)/k; where k=32 In this example, the filter cutoff frequencies of HiPassSpeed and LowPassSpeed are 2.0% of engine speed in rad/sec. However, other percentages can be used. The high pass filter removes the mean speed, leaving only deviations around the mean. This is computationally advantageous, as the subsequent heterodyning step then uses smaller speed values. For example, engine speed variations may be ±50 rpm around a mean of 5000 rpm. It is computationally more efficient, requiring fewer bits, to handle engine speed values around 50 than engine speed values around 5000. However, this step is optional. Engine speed is effectively determined as an average value over regular angular intervals. The use of sampling in the angular domain inherently provides a comb filter, removing higher harmonics at multiples of the sampling frequency. No additional anti-aliasing filter is required. Box 106 corresponds to updating the sine and cosine table values. In one example, the following approach was used: Index[HALF]=Index[HALF]+Count if Index[HALF]>=2N then Index[HALF]=Index[HALF]−2N Index[FIRST]=Index[FIRST]+Count if Index [FIRST]>=2N then Index[FIRST]=Index[FIRST]−2N Box 108 corresponds to heterodyning (or multiplying) the high pass filtered engine speed values with the sine and cosine values. The sine and cosine table indices are updated once per speed measurement event. The resultant heterodyned signals are then passed through a first order, infinite impulse response low pass filter. The multiplication and low pass filter step approximates a convolution of the engine speed values and sine/cosine values signals, but is computationally simpler. For example, the following approach can be used which combines the heterodyning and low pass functions: Real[HALF]n=(HiPassSpeednCos Table[IndexHalf]−Real[HALF]n−1)/k+Real[HALF]n−1 Img[HALF]n=(HiPassSpeednSin Table[IndexHalf]−Img[HALF]n−1)/k+Img[HALF]n−1 Real[FIRST]n=(HiPassSpeednCos Table[IndexFirst]−Real[FIRST]n−1)/k+RealSeries[FIRST]n−1 Img[FIRST]n=(HiPassSpeednSin Table[IndexFirst]−Img[FIRST]n−1)/k+Img[FIRST]n−1 Here, the HighPassSpeed values are high-pass filtered speed values provided by Box 104. As discussed above, the high-pass filtering is optional, and actual speed values can be used instead. Real(HALF) corresponds to cosine multiplied engine speed values, and Img(HALF) corresponds to sine multiplied engine speed values, where the cosine and sine functions having a half-order period. The use of the term “real” to refer to cosine multiplied values is conventional. Cos Table[IndexHalf] corresponds to a cosine value taken from a look-up table. The subscripts n and n−1 refer to latest determined values and previous determined values, respectively. A value of k=32 is used, so that the cut-off frequency of the order components are again 2% of the engine speed in rad/sec. However, other values can be used. Box 110 corresponds to the return from the algorithm, in this example including four values. The four values returned correspond to the sine and cosine heterodyned speed signals at half-order and first-order frequencies, the values having being passed through a low pass filter. In other examples, the values may be squared before return, or magnitudes calculated within this algorithm. If the angular interval of speed value sampling divides exactly into 360 degrees, the sine and cosine values can be determined for the angular intervals, and the same values repeat exactly each revolution. The situation is complicated if a prescaled pulse train gives an angular interval that is not a simple division of 360 degrees. For example, suppose a toothed wheel sensor provides 41 non-prescaled pulses per revolution, and a prescaling value of 10 is used to provide just over 4 pulses per revolution. For first order measurements, 41 values of sine and cosine are precalculated. For half-order measurements, 82 values of sine and cosine values are precalculated (corresponding to two revolutions of the engine). The Count value (see above) can be used to keep track of engine angular position, for example using modulo-N arithmetic to determine which values from the tables are used in the multiplication step. FIG. 6 shows a schematic of an engine management system according to the present invention. The system comprises engine 120, speed sensor 122, cylinder controller 124, misfire detector 126, camshaft sensor 128, operator interface 130, catalytic converter 132, wheel speed sensor 134, and warning 136. The figure shows engine 120 with speed sensor 122 providing a signal to a misfire detector 126. The speed sensor can be a crank shaft position sensor. The misfire detector detects an engine misfire according to the present invention, for example detecting half-order engine speed variations as described above, and provides an output corresponding to the presence or otherwise of a misfire, and also the identification of the misfiring cylinder. The latter aspect is discussed in more detail below. In this example, the misfire detector also receives a wheel speed signal from a wheel speed sensor 134. Engine speed variations can be induced by wheel speed variations, for example due to rough road (such as potholes, dirt roads, and the like), railroad tracks, ice, or other road surface conditions, and this effectively creates noise in the engine speed values. The wheel speed signal can be used to reduce or eliminate the effect of such noise. For example, a threshold value can be raised for misfire detection, or apparent misfire detections ignored, if wheel speed variations are over a certain limit. The effect of wheel speed variations on engine speed can be also be compensated for through an additional algorithm. If a misfire is detected, the misfire detector triggers an engine light or other warning 136, which may be accompanied by an audible alert to the driver. A visible, acoustic, and/or haptic warning can be provided to the vehicle operator using warning 136. The misfire detector may also receive temperature signals from a catalyst temperature sensor within the catalytic converter 132, and may provide signals so as to protect the catalytic converter in the event of a persistent misfire. For example, air, nitrogen, or other gas may be directed over the catalyst surface using a catalyst protection system associated with the catalytic converter. The misfire detector also receives a signal from a camshaft sensor 128. The camshaft sensor facilitates identification of the misfiring cylinder. The misfire detector sends a signal to cylinder controller 124 associated with the misfiring cylinder, which may disable this cylinder. This may lead to a degradation of engine performance, but protects the catalytic converter from rapid destruction or degradation. An operator interface 130 allows an operator to initialize the misfire detector, and to monitor information provided by the misfire detector. For example, the operator interface may allow an engine operator to set the threshold value. The engine operator may also view the level of engine speed variation signatures in the output of the misfire detector, for example to monitor the quality of engine performance. Examples of the present invention may also detect other engine malfunctions which lead to engine speed variations. FIG. 7 illustrates catalyst temperature and output from a misfire detector, as a function of time, with the engine continuing to misfire after the first detection occurs. Before misfire, the catalyst temperature remains at approximately 1600° F., but after misfire the catalyst temperature rapidly increases towards 1900° F. The engine speed variation at first order in rpm, the misfire term, is the lower curve on the left of the figure, but increases by a factor of approximately forty after misfire occurs. The baseline level is approximately 4 rpm, allowing a threshold value to be set, for example, at 10-20 rpm. After misfire, the misfire term approaches 80. FIG. 8 shows a similar situation to that of FIG. 7, but in this case the misfiring cylinder is disabled soon after the misfire is detected. In this case the rise in catalyst temperature is within typical fluctuations, and there is no risk of damage to the catalytic converter. The disablement of the misfiring figure can be achieved automatically if the misfire term, as discussed above in relation to FIG. 7, goes above a threshold value. Computational Efficiency A full Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) is unnecessary and computationally wasteful in connection with the present misfire detection approach. A traditional DFT computation requires 4*N multiply and accumulates per order to update the computation of each order. If one update per sample is desired, the 4N multiply and accumulate steps can be done for each sample with data stored in a first-in, first-out buffer. Then the buffer contents can be integrated to complete the convolution. Traditional DFTs also sample at fixed time intervals, which requires interpolation to convert data which was acquired at fixed angular intervals. This interpolation process requires sine and cosine coefficients required for DFT computations to be done in real time. In contrast, the present approach allows sine and cosine values to be pre-calculated, increasing computational efficiency. Also, the multiplication step is done at fixed angular intervals, rather than at fixed time intervals. This both simplifies the computation, and provides increased accuracy. The integration required in a DFT is also a FIR (finite impulse response) low pass filter with a rectangular sampling window. As an alternative, a first order IIR (infinite impulse response) filter may be used, and the algorithm can be updated every sample point with only 2 multiplies per order. An efficient IIR filter can then be implemented using shift and add techniques. Hence, if a partial DFT is computed in the angular displacement domain (rather than the time domain), no complicated interpolation process is required and if a low-pass filter is used, no integration is required. The engine speed variation is repetitive in the angular displacement domain as well as the time domain. In other words, the sample window maybe computed over 2N samples over 720 degrees as well as 2N samples distributed over a time period of 2T. The results are nearly identical if the magnitude of engine speed variation is small relative to the mean engine speed. Also, sine and cosine coefficients for the DFT can be pre-computed in a lookup table, which greatly increases computational efficiency. Examples of the present invention use integer or fixed points arithmetic, which provides efficiency advantages over floating point arithmetic. However, accuracy is degraded by a slight amount, such as one or two percent. However, since the difference between misfire and non-misfire situations is typically much greater than one percent (for example, ˜1000%) this loss of accuracy does not affect the ability of the present system to reliably detect engine misfires. An advantage over the prior art is that sine and cosine tables are indexed in the angular domain, rather than time domain, and can be precomputed. Further, an infinite impulse response filter, not a numerical integral, can be used to emulate the analog response of a low pass filter. The term “infinite” in “infinite impulse response filter” refers to the exponential decay time of the function, going to zero at infinity. Further Discussion of Low Pass Filter The low pass filter used in examples of the present invention uses software to emulate an analog (such as capacitive resistor) low pass filter. A shift operation in binary is used, equivalent to dividing by an order of two. As the data is already in binary, effectively the decimal point is shifted one or more positions to the left. In examples of the present invention a new filtered value is derived by the following equation:New(filtered)=[New(input)−Old(filtered)]/k+Old(filtered) where New(filtered) is the new filtered value, or output of the low pass filter, New(input) is the new value at the input of the low pass filter, and Old(filtered) is the previous output filtered value. The value k should be greater than one. If k is chosen as a multiple of two, there is efficiency in computation as discussed above as a shift operation can be used to perform the division. In examples of the present invention, a value of k=32 was used. The magnitude of engine speed variations calculated after low pass filtering is not only sensitive to exactly on-order signals, but is also responsive to close spectral components. A lower value of k means a higher value of cutoff frequency, and effectively provides a wider filter pass-band around the order of interest. A value of k can be chosen such that intermittent misfires are detected, but not such that typical noise origin data does not cause a false positive. Using a value k=32, the pass band (to −3 dB) was found to be approximately 2% of engine speed. In example laboratory tests, the value k=32 was found empirically to be responsive to engine misfires without providing false positives. However, other values of k may be chosen. This form of software based low pass filter does not have a fixed filter pass band, and the pass band increases with engine speed. This is highly advantageous, since this means sensitivity does not vary too much with changing average engine speed. The present invention can be executed by a software program using digital data, however other approaches combining digital and analog, or all analog approaches may be used. A low pass filter can operate by detecting an offset or d.c. value in time-averaged results. If there is no engine speed variation, the product of engine speed and sine/cosine tables produces unmodified sine/cosine functions, which average over time to zero. When engine speed variations occur, the sine/cosine functions are modified by the multiplication process, and may no longer average to zero. The size of the offset from zero depends on the magnitude of the engine speed variations at the order of interest. The examples discussed below provide a computationally simple approach to determining engine speed variations, however other approaches can be used as will be clear to those skilled in the mathematical arts. By measuring the mean velocity over the time period between sample points (when pulses are received from the speed sensor), a natural comb filter is formed which reduces the risk of aliasing higher orders down in to the half order and first order components of interest. Misfire Detection and Threshold Levels Misfire can be detected by comparing the magnitude of engine speed variations at a given order to a threshold speed variation (for example, a predetermined constant value), and if the determined speed variation is greater than the threshold speed variation, a misfire or other engine malfunction is indicated and appropriate engine management steps taken or an operator warning provided. The threshold speed variation can be determined by idling the engine under non-misfire conditions, to determine a baseline speed variation at the order of interest. For example, the baseline speed variation at half-order for a typical idling automobile engine may be around 1-5 rpm. With one cylinder misfiring, the half-order speed variation may be 10-40 times greater than the baseline. Hence, the threshold can be set at some multiple of the baseline, but less than the increase associated with misfire. For example, the threshold may be 2-5 times the baseline level, such as twice or three times the baseline level. The determined engine speed variations need not be in any conventional measurement units, as misfire and other engine malfunctions can be determined using comparison of relative values. However, appropriate scaling can be used to provide an engine speed variation in a human-friendly unit such as rpm. Similarly, the speed values provided by the engine speed analyzer need not be in conventional units of speed. The large change in first-order and/or half-order engine speed variations with development of an engine misfire allows misfire detection to occur reliably, and false misfire detections are largely eliminated. False engine malfunction detections may arise from, for example, a rough road surface, or highly dynamic throttle motion as discussed further below. If the square of engine speed variations is determined, this can be compared with a threshold value that is a similar multiple of the square of baseline engine speed variations. Speed Sensor Many modern automobiles are already provided with a speed sensor, hence a misfire detector according to the present invention may be configured to receive an existing speed sensor signal. A speed sensor may be, for example, a passive sensor providing one pulse per tooth of a rotating flywheel, or a Hall Effect sensor. Alternatively a pulse may be provided every M teeth, M being chosen to reduce the pulse number per revolution to some value equal to or greater than the minimum required. For example, a pulse frequency divider can be used to obtain, for example, three, four, or more pulses per revolution using a speed sensor providing a similar or greater number of pulses per revolution. The number of speed samples per revolution need not be an integer. More samples than necessary per revolution can be used, with the cost of added computational effort. A representative speed sensor is described in U.S. Pat. No. 5,717,133. The (substantially instantaneous) engine speed values can be determined by measuring the time period between known angular displacements of the crank shaft and computing the speed value S=C/T where C is a conversion constant and T is the time between the (possibly fixed) angular crankshaft displacement, for example as measured by a high resolution timer with microsecond or sub-microsecond precision. The speed sensor may also provide an analog output, which may be sampled N times per revolution. The sampling process may include averaging an analog signal over an angular interval, such as 360/N degrees. Multiplications may also be performed by analog circuitry, as is well known to those skilled in the electronics arts. Cylinder Identification The cylinder can be identified by determining the angle between real and imaginary components of the engine speed variation, the components equivalent to the cosine and sine multiplied signals respectively. A reference signal can be used to indicate cylinder number one, for example, which can be used to reset the sine and cosine tables. Sometimes, a reference signal is provided, for example by a different tooth or other additional signal from the speed sensor. Alternatively, a separate camshaft sensor can be used to provide a reference signal. Engine Figure of Merit An apparatus according to the present invention can also be used to determine the quality of operation of an engine, alternatively the engine figure of merit. Since this algorithm is sensitive to power imbalances between cylinders, a measurement of torsional vibration quality may be ascertained. This may be defined as the average speed variation at either half-order or first-order. A typical value is, for example, 4 rpm-peak at normal running conditions. The invention is not restricted to the illustrative examples described above. Examples are not intended as limitations on the scope of the invention. Methods, apparatus, algorithms, and the like described herein are exemplary and not intended as limitations on the scope of the invention. In other examples, methods and components of apparatus can be combined or distributed in ways other than illustrated. Changes therein and other uses will occur to those skilled in the art. The scope of the invention is defined by the scope of the claims. Patents, patent applications, or publications mentioned in this specification are incorporated herein by reference to the same extent as if each individual document was specifically and individually indicated to be incorporated by reference. In particular, U.S. Prov. Pat. App. Ser. No. 60/628,334, filed Nov. 15, 2004, is incorporated herein by reference.
	claims	1. A control rod drive system for a nuclear reactor vessel, the system comprising:a reactor vessel having a top head and an interior cavity;a nuclear fuel core supported in the interior cavity of the reactor vessel;a rod cluster control assembly comprising a plurality of control rods configured for removable insertion into the nuclear fuel core;a control rod drive mechanism mounted externally to the reactor vessel above the top head;a drive rod mechanically coupled to the control rod drive mechanism and extending through the top head of reactor vessel into the interior cavity, the control rod drive mechanism operable to raise and lower the drive rod through a plurality of vertical axial positions;a grapple assembly connected to the drive rod inside the interior cavity of the reactor vessel and movable with the drive rod, the grapple assembly including an electromagnet;a drive rod extension extending axially between the rod cluster control assembly and the grapple assembly, the drive rod extension including a bottom end releasably coupled to the rod cluster control assembly in a non-locking manner and a top end releasably coupled to the grapple assembly via the electromagnet; anda longitudinally-extending drive rod extension support structure mounted in the reactor vessel above the nuclear fuel core, the support structure including a plurality of vertically-oriented guide tubes, at least one of the guide tubes which is configured to slideably receive the drive rod extension therein for axial upward and downward movement;wherein the electromagnet is operable to magnetically couple the drive rod extension to the grapple assembly when the electromagnet is energized and uncouple the drive rod extension from the grapple assembly when the electromagnet is de-energized;wherein de-energizing the electromagnet drops and uncouples the drive rod extension from the rod cluster control assembly remotely at the bottom of the drive rod extension. 2. The system of claim 1, wherein the drive rod extension includes:an axially extending actuator shaft having a top end extending above the drive rod extension support structure and including a magnetic block releasably engageable with the electromagnet of the grapple assembly, the actuator shaft further including a bottom end releasably engageable with the rod cluster control assembly; anda lifting head sleeve including a diametrically enlarged lifting head selectively engageable with the grapple assembly, the lifting head sleeve slideably receiving the actuator shaft therethrough for axial upward and downward movement. 3. The system of claim 2, wherein the drive rod extension support structure includes a retaining collar receiving a portion of the lifting head sleeve therein, the retaining collar having radially-acting spring-loaded retaining pins configured and arranged to releasably engage the lifting head sleeve. 4. The system of claim 3, wherein when the lifting head sleeve is engaged with the retaining collar, the actuator shaft is moveable upwards independently of the lifting head sleeve by energizing the electromagnet and raising the grapple assembly. 5. The system of claim 4, wherein when the lifting head sleeve is not engaged with the retaining collar, the actuator shaft is moveable upwards together with the lifting head sleeve by raising the grapple assembly when the electromagnetic is energized. 6. The system of claim 3, wherein the lifting head sleeve includes an outwardly protruding annular stop flange arranged to engage a top surface of the retaining collar to limit an insertion depth of the lifting head sleeve through the retaining collar into the at least one of the guide tubes. 7. The system of claim 1, wherein responsive to a loss of power to the electromagnet, the drive rod extension is released from the grapple assembly and drops vertically to automatically uncouple the rod cluster control assembly from the drive rod extension for full insertion of the control rods into the fuel core while the drive rod and grapple assembly remain stationary in axial position. 8. The system of claim 2, wherein the grapple assembly includes a cylindrically shaped body defining a downwardly open chamber configured to movably receive the top end of the drive rod extension and the lifting head therein. 9. The system of claim 8, wherein the chamber of the grapple assembly further includes a plurality of radially retractable lifting pins engageable with the lifting head of the drive rod extension. 10. The system of claim 9, further comprising a diametrically enlarged bobbin slideably disposed and axially movable on the lifting head sleeve, the bobbin operable to selectively engage the lifting head and enter the downwardly open chamber of the grapple assembly. 11. The system of claim 10, wherein the bobbin is configured and operable to enter a downwardly open cavity of the lifting head in a nested relationship. 12. The system of claim 11, wherein the bobbin is engageable with the retractable lifting pins of the grapple assembly when the bobbin is nested in the cavity of the lifting head. 13. The system of claim 10, wherein the bobbin is engageable with the retractable lifting pins of the grapple assembly. 14. The system of claim 2, wherein the bottom end of the drive rod extension includes a locking mechanism comprising radially movable locking elements releasably engageable with the rod cluster control assembly, the locking elements movable between an outward locked position coupling the drive rod extension to the rod cluster control assembly and an inward unlocked position uncoupled from the rod cluster control assembly. 15. The system of claim 14, wherein the locking elements are locking balls radially movable between the locked and unlocked positions by raising or lowering the drive rod extension with the drive rod and grapple assembly. 16. The system of claim 15, wherein the locking balls are arranged to selectively engage an annular groove formed on the rod cluster control assembly in the locked position thereby coupling the drive rod extension to the rod cluster control assembly. 17. The system of claim 16, wherein the locking balls are mounted in an adapter sleeve coupled to a bottom end of the lifting head sleeve, and the actuator shaft is axially slideable inside the adapter sleeve and configured to selectively engage and move the locking balls laterally outwards and inwards between the locked and unlocked positions. 18. The system of claim 17, further comprising an actuator cap attached to a bottom end of the actuator shaft and including an upper end portion and a diametrically larger lower end portion engageable with the locking balls, the upper end portion having a diameter which does not engage the locking balls, wherein moving the actuator shaft upwards relative to the adapter sleeve engages the lower end portion of the actuator cap with the locking balls to force them outwards to the locked position. 19. The system of claim 1, wherein the guide tubes of the drive rod extension support structure each include an upper guide tube and a lower guide tube having a larger diameter than the upper guide tube, the rod cluster control assembly being configured for upwards and downwards movement within the lower guide tube. 20. The system of claim 19, wherein the nuclear fuel core is disposed inside a tubular core support structure located in a lower portion of the interior cavity of the reactor vessel, the core support structure sitting atop the core support structure in the interior cavity, and wherein the guide tubes of the drive rod extension support structure include a plurality of perforations in fluid communication with the primary coolant flow.
	summary
	claims	1. An arrangement device comprising:a movement section, which relatively moves and arranges at least one of a semiconductor integrated circuit body and a substrate with respect to the other thereof, the semiconductor integrated circuit body includinga semiconductor integrated circuit which includes an optical communication element for performing optical communication andan interposer which is to be interposed between the semiconductor integrated circuit and the substrate, a through-hole being provided in the interposer and the interposer including, at the through-hole, a transparent member which includes an optical system for focusing light for the optical communication, andthe substrate including an optical waveguide, through which light of optical communication passes; anda detection section, which detects an offset amount between a first optical axis, of the optical communication element, and a second optical axis, of the optical system,wherein the movement section relatively moves the at least one of the semiconductor integrated circuit body and the substrate with respect to the other on the basis of the offset amount which has been detected by the detection section. 2. The arrangement device of claim 1, whereina first distinguishing mark has been applied beforehand to the semiconductor integrated circuit body and a second distinguishing mark has been applied beforehand to the substrate,the arrangement device further includes a photography section, which photographs the first distinguishing mark and the second distinguishing mark,the detection section detects the offset amount on the basis of positions of the first distinguishing mark and second distinguishing mark photographed by the photography section, andthe movement section relatively moves the at least one of the semiconductor integrated circuit body and the substrate with respect to the other such that the first distinguishing mark and the second distinguishing mark approach one another in an image obtained by the photography and form a complete distinguishing mark which is determined in accordance with the offset amount. 3. An arrangement method comprising:relatively moving and arranging at least one of a semiconductor integrated circuit body and a substrate with respect to the other thereof the semiconductor integrated circuit body includinga semiconductor integrated circuit which includes an optical communication element for performing optical communication andan interposer which is to be interposed between the semiconductor integrated circuit and the substrate, the interposer including a transparent member which includes an optical system for focusing light for the optical communication, andthe substrate including an optical waveguide, through which light of optical communication passes; anddetecting an offset amount between a first optical axis, of the optical communication element, and a second optical axis, of the optical system,wherein the step of moving includes relatively moving the at least one of the semiconductor integrated circuit body and the substrate with respect to the other on the basis of the offlet amount which has been detected in the detecting. 4. The arrangement method of claim 3, whereina first distinguishing mark has been applied beforehand to the semiconductor integrated circuit body and a second distinguishing mark has been applied beforehand to the substrate,the arrangement method further includes the step of photographing the first distinguishing mark and the second distinguishing mark,the step of detecting includes detecting the offset amount on the basis of positions of the first distinguishing mark and second distinguishing mark photographed in the photographing andthe step of moving includes relatively moving the at least one of the semiconductor integrated circuit body and the substrate with respect to the other such that the first distinguishing mark and the second distinguishing mark approach one another in an image obtained by the step of photographing and form a complete distinguishing mark which is determined in accordance with the offset amount. 5. An arrangement device comprising:a photography section, which photographs a first mark, a second mark and a third mark in a state in which a semiconductor integrated circuit to which the first mark is applied, an interposer to which the second mark is applied and a substrate to which the third mark is applied overlap, the interposer being for interposing between the semiconductor integrated circuit and the substrate; anda movement section, which relatively moves at least one of the semiconductor integrated circuit, the interposer and the substrate with respect to the others thereof on the basis of positions of the first mark, the second mark and the third mark which have been photographed by the photography section so that the first mark, the second mark, and the third mark come close to each other to form a complete mark and the semiconductor integrated circuit and the substrate become combined in a pre-specified position, wherein the movement section performs at leasta first movement, for relatively moving at least one of the semiconductor integrated circuit and the interposer with respect to the other thereof such that the first mark and the second mark approach one another in an image obtained by the photography and form a pre-specified distinguishing mark, anda second movement, for relatively moving at least one of a body including the semiconductor integrated circuit with the interposer and the substrate with respect to the other thereof such that the distinguishing mark and the third mark approach one another in an image obtained by the photography and finally form a pre-specified complete distinguishing mark. 6. An arrangement device comprising:a photography section, which photographs a first mark, a second mark and a third mark in a state in which a semiconductor integrated circuit to which the first mark is applied, an interposer to which the second mark is applied and a substrate to which the third mark is applied overlap, the interposer being for interposing between the semiconductor integrated circuit and the substrate; anda movement section, which relatively moves at least one of the semiconductor integrated circuit, the interposer and the substrate with respect to the others thereof on the basis of positions of the first mark, the second mark and the third mark which have been photographed by the photography section so that the first mark, the second mark, and the third mark come close to each other to form a complete mark and the semiconductor integrated circuit and the substrate become combined in a pre-specified position, wherein the movement section performs at leasta first movement, for relatively moving at least one of the semiconductor integrated circuit and the interposer with respect to the other thereof such that the first mark and the second mark approach one another in an image obtained by the photography and form a pre-specified distinguishing mark, anda second movement, for relatively moving at least one of a body including the semiconductor integrated circuit with the interposer and the substrate with respect to the other thereof such that the distinguishing mark and the third mark approach one another in an image obtained by the photography and finally form a pre-specified complete distinguishing mark,wherein the first mark, the second mark and the third mark are reflective of X-rays, andfor photographing the distinguishing mark and the third mark, the photography section employs X-rays and passes the X-rays through at least one of the substrate and the body including the semiconductor integrated circuit with the interposer. 7. An arrangement method comprising the steps ofphotographing a first mark, a second mark and a third mark in a state in which a semiconductor integrated circuit to which the first mark is applied, an interposer to which the second mark is applied and a substrate to which the third mark is applied overlap, the interposer being for interposing between the semiconductor integrated circuit and the substrate; andrelatively moving at least one of the semiconductor integrated circuit, the interposer and the substrate with respect to the others thereof on the basis of positions of the first mark, the second mark and the third mark which have been photographed in the photographing so that the first mark, the second mark, and the third mark com close to each other to form a complete mark and the semiconductor integrated circuit and the substrate become combined in a pre-specified position, wherein the step of moving comprises:relatively moving at least one of the semiconductor integrated circuit and the interposer with respect to the other thereof such that the first mark and the second mark approach one another in an image obtained by the photography and form a pre-specified distinguishing mark, andrelatively moving at least one of a body including the semiconductor integrated circuit with the interposer and the substrate with respect to the other thereof such that the distinguishing mark and the third mark approach one another in an image obtained by the photography and finally form a pre-specified complete distinguishing mark. 8. An arrangement method comprising the steps ofphotographing a first mark, a second mark and a third mark in a state in which a semiconductor integrated circuit to which the first mark is applied, an interposer to which the second mark is applied and a substrate to which the third mark is applied overlap, the interposer being for interposing between the semiconductor integrated circuit and the substrate: andrelatively moving at least one of the semiconductor integrated circuit, the interposer and the substrate with respect to the others thereof on the basis of positions of the first mark, the second mark and the third mark which have been photographed in the photographing so that the first mark, the second mark, and the third mark com close to each other to form a complete mark and the semiconductor integrated circuit and the substrate become combined in a pre-specified position,wherein the step of moving comprises:relatively moving at least one of the semiconductor integrated circuit and the interposer with respect to the other thereof such that the first mark and the second mark approach one another in an image obtained by the photography and form a pre-specified distinguishing mark, andrelatively moving at least one of a body including the semiconductor integrated circuit with the interposer and the substrate with respect to the other thereof such that the distinguishing mark and the third mark approach one another in an image obtained by the photography and finally form a pre-specified complete distinguishing mark, andwherein the first mark, the second mark and the third mark are reflective of X-rays, andthe step of photographing includes employing X-rays and transmitting the X-rays through at least one of the substrate and the body including the semiconductor integrated circuit with the interposer for photographing the distinguishing mark and the third mark.
	summary
	claims	1. A digital protection system comprising:a process protection system comprising at least two channels, each of the at least two channels comprising a first bistable logic controller and a second bistable logic controller which is independent and of a different type from the first bistable logic controller, the first bistable logic controller and the second bistable logic controller receiving a process parameter and respectively outputting first and second bistable logic results based on the process parameter, the first bistable logic result comprising one of a first normal signal and a first abnormal signal; anda reactor protection system comprising at least two trains, at least two initiation circuits, and a parallel circuit that includes a plurality of relays connected in parallel,wherein each of the at least two initiation circuits comprises a serial circuit in which a plurality of relays are serially connected,wherein each of the two trains comprises a first coincidence logic controller and a second coincidence logic controller which is independent and of a different type from the first coincidence logic controller, the first coincidence logic controller and the second coincidence logic controller respectively outputting first and second coincidence logic results based on the first and second bistable logic results, the first coincidence logic controller receiving the first bistable logic result from the first bistable logic controller included in each of the at least two channels and outputting the first coincidence logic result based on a count of the first bistable logic result and a count of the first abnormal signal,wherein the plurality of relays included in the serial circuit are switched on or off based on the first and second bistable logic results, and the plurality of relays included in the parallel circuit are switched on or off based on the first and second coincidence logic results, andwherein the first coincidence logic result comprises a first output signal and a second output signal that is different from the first output signal, the first output signal being input to a first relay of the plurality of relays included in the serial circuit, the second output signal being input to a first relay of the plurality of relays included in the parallel circuit. 2. The digital protection system of claim 1, wherein the process protection system comprises a first channel, a second channel, a third channel, and a fourth channel. 3. The digital protection system of claim 1, wherein the reactor protection system comprises a first train and a second train. 4. The digital protection system of claim 1, wherein the process protection system comprises a first bistable logic controller based on a field programmable gate array (FPGA), and a second bistable logic controller based on a programmable logic controller (PLC). 5. The digital protection system of claim 1, wherein each of the first and the second bistable logic controllers transmits the first and second bistable logic results to all coincidence logic controllers that have a same type of a logic structure. 6. The digital protection system of claim 1, wherein the process parameter comprises at least one of temperature information about a high temperature pipe and a low temperature pipe of a reactor coolant, pressurizer pressure information, pressurizer water level information, neutron flux information, reactor coolant flow rate information, containment building pressure information, steam generator water level information, steam pipe pressure information, and refueling water tank water level information. 7. The digital protection system of claim 1,wherein the second coincidence logic controller receives the second bistable logic result comprising one of a second normal signal and a second abnormal signal from the second bistable logic controller included in each of the at least two channels and outputs the second coincidence logic result based on a count of the second bistable logic result and a count of the second abnormal signals, andwherein the second coincidence logic result comprises a third output signal and a fourth output signal that is different from the third output signal, the third output signal being input to a second relay of the plurality of relays included in the serial circuit, the fourth output signal being input to a second relay of the plurality of relays included in the parallel circuit. 8. The digital protection system of claim 7,wherein the first coincidence logic controller outputs the first coincidence logic result in response to the first bistable logic result comprising at least one abnormal signal, the first coincidence logic result being a logic “0” input to the first relay of the plurality of relays included in the serial circuit and being a logic “1” input to the first relay of the plurality of relays included in the parallel circuit, andwherein the second coincidence logic controller outputs the second coincidence logic result in response to the second bistable logic result comprising at least one abnormal signal, the second coincidence logic result being a logic “0” input to the second relay of the plurality of relays included in the serial circuit and being a logic “1” input to the second relay of the plurality of relays included in the parallel circuit. 9. The digital protection system of claim 7,wherein the first coincidence logic controller outputs a coincidence logic result in response to the first and second bistable logic results comprising at least one normal signal, the coincidence logic result being a logic “1” input to the first relay of the plurality of relays included in the serial circuit and being a logic “0” input to the first relay of the plurality of relays included in the parallel circuit, andwherein the second coincidence logic controller outputs a coincidence logic result in response to the first and second bistable logic results comprising at least one normal signal, the coincidence logic result being a logic “1” input to the second relay of the plurality of relays included in the serial circuit and being a logic “0” input to the second relay of the plurality of relays included in the parallel circuit. 10. The digital protection system of claim 1, further comprising an reactor trip switchgear system (RTSS), wherein the RTSS comprises:a first normally open (NO) contact point disposed between a power node and a central node;a second NO contact point disposed between the power node and the central node;a third NO contact point disposed between the central node and a control element drive mechanism (CEDM); anda fourth NO contact point disposed between the central node and the CEDM. 11. The digital protection system of claim 10, wherein when at least one of the first NO contact point and the second NO contact point is in a closed state and at least one of the third NO contact point and the fourth NO contact point is in a closed state, motor-generator set (MG-SET) power is applied to the CEDM. 12. The digital protection system of claim 10, wherein when both of the first NO contact point and the second NO contact point are in opened states and both of the third NO contact point and the fourth NO contact point are in opened states, MG-SET power applied to the CEDM is shut down. 13. The digital protection system of claim 10, wherein at least one of the at least two initiation circuits comprises:a first serial circuit configured to control a conduction state of the first NO contact point according to output signals of the coincidence logic controller;a first parallel circuit configured to control a conduction state of the second NO contact point according to output signals of the coincidence logic controller;a second parallel circuit configured to control a conduction state of the third NO contact point according to output signals of the coincidence logic controller; anda second serial circuit configured to control a conduction state of the fourth NO contact point according to output signals of the coincidence logic controller. 14. The digital protection system of claim 13, wherein the first serial circuit and the first parallel circuit receive output signals from the first coincidence logic controller and the second coincidence logic controller that has a same logic structure as the first coincidence logic controller and included in any one of the at least two trains. 15. The digital protection system of claim 14, wherein the second parallel circuit and second serial circuit receive output signals from the first coincidence logic controller and the second coincidence logic controller that has a same logic structure as the first coincidence logic controller and included another train of the at least two trains. 16. The digital protection system of claim 13, wherein at least one of the at least two initiation circuits comprises:a third circuit that comprises a relay and is configured to switch on or off the relay included in the third circuit to control the conduction state of the second NO contact point; anda fourth circuit that comprises a relay and is configured to switch on or off the relay included in the fourth circuit to control the conduction state of the third NO contact point,wherein the first parallel circuit controls to switch on or off the relay included in the third circuit, and the second parallel circuit controls to switch on or off the relay included in the fourth circuit. 17. The digital protection system of claim 16, wherein the relays included in the third circuit and the fourth circuit are normally-closed (NC) contact points. 18. The digital protection system of claim 16, whereinthe first serial circuit or the second serial circuit comprises two relays that are serially connected, and the two relays are switched on or off according to output signals of the coincidence logic controller, andwhen all relays are switched on, the first NO contact point or the fourth NO contact point is closed, or when at least one of the two relays is switched off, the first NO contact point or the fourth NO contact point is opened. 19. The digital protection system of claim 16, whereinthe first parallel circuit or the second parallel circuit comprises two relays that are connected in parallel,the two relays are switched on or off according to output signals of the coincidence logic controller, andwhen all relays included in the first parallel circuit or the second parallel circuit are switched off, the relay included in the third circuit or the fourth circuit is switched on, or when at least one of the two relays included in the first parallel circuit or the second parallel circuit is switched on, the relay included in the third circuit or the fourth circuit is switched off.
052895130	summary	CROSS REFERENCE TO RELATED APPLICATIONS This patent application is related to copending U.S. patent application Ser. No. 07/884,972 titled "A Nuclear Fuel Assembly For Increasing Utilization Of Nuclear Fuel Contained Therein" filed May 15, 1992 in the name of David R. Stucker and copending U.S. patent application Ser. No. 07/968,647 titled "Fuel Assembly Including Deflector Vanes For Deflecting A Component Of A Fluid Stream Flowing Past Such Fuel Assembly" filed Oct. 29, 1992 in the name of Edmund E. DeMario et al. BACKGROUND This invention generally relates to fuel assembly spacer grids and more particularly relates to a method of making a fuel assembly lattice member and the lattice member made by such method. Fuel assembly spacer grids are known. One such spacer grid is disclosed in U.S. Pat. No. 3,281,327 titled "Nuclear Fuel Assemblies" issued Oct. 5, 1966 in the name of John Webb, et al. This patent discloses a spacer grid comprising a support member in the form of an outer metal sleeve of regular hexagonal cross-section. This patent also discloses that the spacer grid has a parallel array of spacer diaphragms adapted to be penetrated by fuel elements. According to this patent, the spacer diaphragms act as deflector vanes imparting to a main flow stream a component of flow transversely of the fuel elements. Although the Webb, et al. patent discloses a fuel assembly spacer grid comprising a support member in the form of an outer metal sleeve of regular hexagonal cross-section, the Webb et al. patent does not appear to disclose a method of making a fuel assembly lattice member and the lattice member made by such method, as described and claimed hereinbelow. Another fuel assembly spacer grid is disclosed in U.S. Pat. No. 4,547,335 titled "Fuel Rod Support Grid" issued Oct. 15, 1985 in the name of Robert E. Downs et al. This patent discloses a support grid for triangular arrays of nuclear fuel rods associated with hexagonal fuel assemblies. Although the Downs, et al. patent discloses a support grid for hexagonal fuel assemblies, the Downs et al. patent does not appear to disclose a method of making a fuel assembly lattice member and the lattice member made by such method, as described and claimed hereinbelow. Although the above recited patents disclose fuel assembly spacer grids, these patents do not appear to disclose a method of making a fuel assembly lattice member and the lattice member made by such method, as described and claimed hereinbelow. Therefore, what is needed is a suitable method of making a fuel assembly lattice member and the lattice member made by such method. SUMMARY Disclosed herein is a method of making a fuel assembly lattice member and the lattice member made by such method. The method includes placing a plurality of elongate metal straps on a computer controlled conveyor which successively conveys the straps into alignment with each of a plurality of computer controlled piercing and drawing dies belonging to a progressive die machine. The dies are selectively actuated by the computer to form such elements as curved deflector vanes and spring members on each strap member. After the piercing and drawing operations are completed, the straps are joined by welding to form a lattice member of hexagonal cross section, the lattice member defining a plurality of rhombic-shaped fuel rod cells and a plurality of generally rhombic-shaped guide tube thimble cells therethrough. The rod cells are capable of receiving respective ones of a plurality of fuel rods and the thimble cells are capable of receiving respective ones of a plurality of thimble tubes. The rhombic shape of the rod cells cooperate with the deflector vanes to deflect a component of a fluid stream about the longitudinal center axis of each fuel rod for maintaining liquid substantially single-phase fluid flow over the surface of each fuel rod in order to avoid Departure from Nucleate Boiling (DNB) on the surface of the fuel rods. An object of the present invention is to provide a method of making a fuel assembly lattice member and the lattice member made by such method. Another object of the present invention is to provide a lattice member for a fuel assembly, the lattice member capable of deflecting a component of a fluid stream flowing past the fuel assembly, so that liquid substantially single-phase coolant flow is obtained over the surface of the fuel rods in order to avoid Departure from Nucleate Boiling (DNB) on the surface of the fuel rods. A feature of the present invention is the provision of a method of making a fuel assembly lattice member comprising the steps of engaging a plurality of metal strap members with a computer controlled conveyor, successively advancing each strap member into alignment with a pneumatically actuatable deflector vane piercing die by controllably moving the conveyor and pneumatically actuating the deflector vane piercing die by operating the computer, so that each strap member is pierced to form at least one deflector vane thereon. Another feature of the present invention is the provision of a method of making a lattice member comprising the steps of advancing a preselected pair of metal strap members into alignment with a pneumatically actuatable trihedral drawing die by controllably moving the conveyor; pneumatically actuating the trihedral drawing die by operating the computer to draw the pair of strap members such that each of the strap members obtains a trihedrally-shaped transverse cross section; and joining the pair of trihedrally-shaped strap members by activating a welding device so as to form an outer strap member having a regular hexagonally-shaped transverse contour. Yet another feature of the present invention is the provision of a lattice member for a fuel assembly, the lattice member being capable of receiving elongate fuel rods therethrough and comprising a plurality of curved deflector vanes thereon for deflecting a component of a fluid stream flowing past the fuel assembly, such that the deflected component of the fluid stream swirls about the longitudinal center axis of each fuel rod. An advantage of the present invention is that it obtains a cost-effective method of making lattice members, the method necessarily requiring only one machine set-up, rather than multiple machine set-ups, in order to efficiently make lattice members of varying designs. Another advantage of the present invention is that it reduces fabrication time for making lattice members. Yet another advantage of the present invention is that it obtains a lattice member that reduces the risk of tool hang-up and resulting damage to the lattice member during reactor refueling operations. Still another advantage of the present invention is that it obtains a lattice member capable of reducing the risk of Departure from Nucleate Boiling (DNB) on the surface of each fuel rod passing through the lattice member. These and other objects, features, and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described illustrative embodiments of the invention.
052689484	summary	BACKGROUND OF THE INVENTION The present invention relates generally to a locking assembly used in conjunction with nuclear reactors to normally lock in place an upper support plate disposed at the top of a fuel bundle, and to selectively permit the easy removal of such support plate when it is necessary or desirable to remove one or more of the fuel rods in the fuel bundle. There are several types of nuclear reactors used to generate power, one of which is the pressurized water reactor (PWR). In a PWR the reactor core contains an array of fuel bundles or assemblies comprised of fuel rods containing uranium. PWR units in the United States generally operate for approximately 12 to 18 months after which the plant is routinely shut down for refueling so that all systems and components can be checked to ensure safety and reliability. Occasionally, fuel will fail during the 12 to 18 months of power operation. Fuel is considered failed when a fuel rod wall is breached and radioactive isotopes are released into the water which cools the fuel during power operation. Failure can result in a number of ways, such as debris in the cooling water fretting the fuel rod in a localized area, or flaws introduced during fuel fabrication. In the past, a small percentage of failed fuel was acceptable, but, recently, emphasis has been placed on eliminating the continued operation of any known failed fuel. When fuel fails, radioactive isotopes are released into the coolant water and should the level of these radioactive isotopes indicate that there is failed fuel, such failed fuel should be promptly removed. Rather than remove an entire fuel assembly from further operation, a more economical solution is to replace only the failed fuel rods with structurally sound replacement rods and return the assembly back to operation. The fuel rods are replaced by disconnecting an upper support plate or upper end fitting from guide tubes forming part of the fuel assembly, thereby allowing the fuel rods to be removed. The replacement or removal of failed fuel rods occurs during the outage when time to perform such work is limited, and, therefore, a need exists for fuel assembly features which allow replacement to be performed as quickly as possible. Early fuel assembly designs did not provide a means for replacement since some failed fuel was acceptable. However, as emphasis was placed on removal of failed fuel, designs were developed to allow replacement. For example, Long et al U.S. Pat. No. 4,064,004 discloses an assembly mechanism which permits the upper support plate to be removed from guide tubes and which includes a pair of cooperating movable members, one of which is operable to be moved to one position at which the upper support plate is normally maintained in place on the guide tubes by lugs, and to be selectively rotated to a second position at which a slot formed in the support plate can be aligned with such lugs to permit removal of the support plate. The other movable member is axially movable and is urged by a coil spring to a normal position at which it prevents the rotatable member from being moved to its aligned position with respect to the support plate slot. In this system, the cooperating locking members are locked together at the support plate release position but they are not locked to the guide tube after the support plate is removed. Therefore, there is no assurance that the locked members will remain at the same orientation relative to the guide tube after the support plate is removed, and they are free to move to a different position on the guide tube which will require that all of the locked members be carefully aligned with the slots on the support plate when the support plate is repositioned on the ends of the guide tubes. In accordance with the present invention, a simplified locking assembly is provided which overcomes the aforesaid drawback of known locking mechanisms, and which provides an arrangement that is easy to operate while providing a secure lock for the upper support plate. SUMMARY OF THE INVENTION Briefly summarized, the present invention provides a locking assembly for permitting the easy removal of fuel rods from a nuclear power reactor fuel bundle and this locking assembly includes a plurality of control rod guide tubes extending upwardly from the fuel bundle, and a support plate that is removably mounted on the guide tubes to permit removal of the fuel rods when the support plate is removed from the guide tubes, this support plate being formed with openings for receiving the extending ends of each of the guide tubes and being formed with a slot extending outwardly from each such opening. A collar assembly is mounted at the extending end of each guide tube for permitting selective removal of the support plate from the guide tubes, and this collar assembly includes a base portion and first and second locking portions mounted on the base portion for movement relative to one another, and one of the locking portions is formed with lugs or projections that correspond generally in shape to the aforesaid slot in the support plate, and one of the locking portions is arranged for movement between a first position at which the aforesaid projection is openly aligned with the slot in the support plate to permit removal of the support plate, and a second position at which the projection is not openly aligned with the slot whereby the plate is locked in place on the guide tubes. A resilient member is associated with the collar assembly for resiliently locking the movable locking portion against movement with sufficient force to maintain it at its second locking position, and for selectively releasing the movable locking portion when a predetermined torsional force is applied to the movable locking portion to thereby permit movement of the movable locking portion to its first aligned position at which the support plate can be removed from the guide tubes. Preferably, the resilient means resiliently locks the movable locking portion against movement by resiliently engaging an annular engagement surface on the second locking portion, and the resilient element is capable of locking the movable locking portion in place at both its first aligned or removal position and at its second locking position. In one embodiment of the present invention, the movable locking portion is arranged for rotational movement with respect to the base portion, and it is formed with a body portion and a slot therein which corresponds in shape to the slot in the support plate. A second locking portion is fixed to the base portion and includes a projection extending outwardly therefrom, and the rotatable locking portion is disposed intermediate this projection and the support plate and is rotatable between a first position at which the slot therein is openly aligned with the slot in the support plate to permit the support plate to pass over the projection for removal, and a second position at which the slot in the movable locking portion is out of alignment with the slot in the support plate and the body portion of the movable locking portion is disposed between the projection and the support plate to block removal of the support plate over such projection. Preferably, the rotatable locking portion includes an exterior annular engagement surface, and the resilient element resiliently engages the annular engagement surface by presenting a spring biased ear that is resiliently engaged at either one of two detents formed in the annular engagement surface. In a second embodiment of the present invention, the movable locking portion is rotatably mounted on the base portion and is formed with a projection that corresponds generally in shape to the support plate slot, and a retaining member is fixed to the guide tube for maintaining the movable locking portion in place on the base portion and permitting it to move between its first and second positions, and, preferably, the fixed element includes an exterior annular wall portion disposed within an adjacent interior annular wall portion on the movable portion, and the fixed element includes at least one, and preferably two, detents formed in the exterior annular wall portion, and a spring biased ear is formed at the interior annular wall of the movable locking portion. In a third embodiment, the collar assembly includes a base portion and a locking portion that is rotatably mounted on the base portion and formed with a projection corresponding generally in shape to the slot in the support plate, and this locking portion is rotatable between first and second positions for releasing and locking in place the support plate, respectively. In this embodiment, the resilient element includes a spring biased element disposed within and adjacent an interior annular engagement surface on the rotatable locking portion, and movable therewith, for resiliently engaging a fixed element on the base with a sufficient force to normally maintain the locking portion at its first position and for releasing the locking portion when a predetermined torsional force is applied thereto. Preferably, the annular engagement surface of the movable locking portion has an inwardly extending protrusion, and the spring biased element is a snap ring positioned within, and movable with the movable locking portion and formed with a spring biased ear for resiliently engaging the fixed element.
059498366	claims	1. An apparatus for sequentially producing a concentration of at least one product isotope by an isotopic conversion reaction, comprising: a) a beam source for generating a photon beam along a beam axis, and b) a target assembly containing increments of target material displaced in-series along the beam axis, said increments including a targeted isotope which converts to the product isotope with irradiation by the photon beam, an increment of the target material proximal to the beam source being removable from the target assembly with product isotope while leaving target material which had been irradiated through the removed increment for further irradiation by the photon beam. f is the isotopic fraction of molybdenum-100 in the molybdenum-100 target, and R is the photon path length per unit volume per unit energy, weighted by the photoneutron cross-section integrated over energy. a) an electron accelerator, and b) a convertor for converting an electron beam into the photon beam. a) directing a photon beam along a beam axis from a photon beam source through target material increments displaced in-series along the axis of the photon beam, a targeted isotope contained within the increments being exposed to said photon beam to form the product isotope within a target material increment proximal to said photon beam source and an increment behind the proximal increment, b) removing a first target material increment proximal to the photon beam source from the photon beam, and c) advancing the target material increments in-series toward the photon beam source. a) The target is molybdenum, and b) f.multidot.R.gtoreq.2.2.times.10.sup.-8 sec.sup.-1, where 2. An apparatus of claim 1 wherein the intensity of the photon beam is at least 50 microamps/cm.sup.2. 3. An apparatus of claim 1 wherein EQU f.multidot.R.gtoreq.2.2.times.10.sup.-8 sec.sup.-1 4. An apparatus of claim 3 further comprising a means for moving target material increments, in series, toward the photon beam source as the proximal target increment, containing product isotope, is removed from the target assembly. 5. An apparatus of claim 4 further comprising a means for inserting an additional target material increment into the target assembly distal to the photon beam generating means. 6. An apparatus of claim 3 wherein the target material is in a solid mass. 7. An apparatus of claim 3 wherein the target material is in a form selected from the group consisting of a liquid, a slurry or particles. 8. An apparatus of claim 7 wherein each increment of target material is separately contained within a container. 9. An apparatus of claim 3 wherein the beam source includes: 10. An apparatus of claim 9 wherein the convertor includes as least two separate convertor plates, disposed within the convertor, wherein the convertor plates have different thicknesses. 11. An apparatus of claim 10 further comprising a means for cooling the convertor, wherein said cooling means includes coolant channels disposed between adjacent convertor plates. 12. An apparatus of claim 2 wherein the photon beam has photons of energy of at least 8 MeV. 13. A method for sequentially producing a concentration of at least one product isotope by an isotopic conversion reaction, comprising the steps of: 14. A method of claim 13 wherein: 15. A method of claim 13 wherein the intensity of the photon beam is at least 50 microamps/cm.sup.2. 16. A method of claim 15 wherein the photon beam has photons or energy of at least 8 MeV.
	claims	1. A three-dimensional fluoroscopy, wherein one X-ray beam is reflected in a left direction and a right direction in alternation for a predetermined exposure time and at a predetermined interval by a rotating mirror, the reflected X-ray beams being further reflected by a pair of mirrors spaced from each other by an interpupillary distance of a human inspector, whereby irradiating two X-ray beams to an object in alternation.
	summary
	description	This invention relates to operating an excitation source and analog front end of a fluorescence emissions detection circuit. Fluorescence is the emission of electromagnetic radiation or light immediately after absorbing incident radiation or light. A resonant fluorescence phenomenon occurs when the spectra or wavelength of the emission overlaps the incident or excitation source wavelength. The delay time between absorption and emission is minimal. The fluorescence lifetime or 1/e value is the time that is equivalent to 36.8% of the initial intensity value of the fluorescing signal. Detecting fluorescence requires receiving the fluorescence emission by a photo sensitive device, converting it to an electrical signal, and amplifying the resulting electrical signal. The spectral power density (SPD) of the excitation source is multiple orders of magnitude higher than the SPD of the emission from the fluorescing material. Because of this, crosstalk in a detection system is an undesired effect of overlapping spectra. A saturated amplifier can substantially degrade the bandwidth and linearity of the system when detecting fluorescence in materials where the fluorescence has a short lifetime. A current analog of the fluorescing emission, as measured in a detection system, may be represented by an exponential equation:f(t)=A+B1(e−t/τ1)+B2(e−t/τ2) (1)In this equation (1), “A” represents a constant background signal such as photodiode dark current or electrical noise or offsets. The coefficients B1 and B2 represent initial emission intensities and the exponents represent the time constants of individual components in the composite emission signal as a function of time, t. It is desirable to accurately detect resonant fluorescence emission signals with time constant components ranging from 10 to 1000 microseconds. A desired output signal is a decaying exponential voltage that is the analog of a resonant fluorescence signal with minimal distortion due to instrumental artifacts and overlapping spectra. It is also desirable to have a light excitation source such as a single light emitting diode (LED) or multiple LEDs with sufficient power and a sufficiently short duration or pulse width. It is also desirable to have a driver for the light source that is compatible with CMOS logic levels such that a single general purpose I/O pin from a microcontroller or DSP can control the turn-ON and turn-OFF timing of the LED. There is a desire for a resonant fluorescence detection system that is simple, reliable, low cost, and able to be configured with high volume LED light sources and photodiode detectors. It is further desirable to have digitally controlled gain, offset, and gating to prevent amplifier saturation and non-linearity in addition to enabling the normalization of detector performance to reduce device to device variance for a wide variety of applications including variances in taggant loading, which may result in lower or higher emission intensity. Aspects of the present invention detect resonant fluorescent emissions from a test material employing a pulsed light source that is gated ON and OFF with a pulsed control signal. The light pulse is coupled into the material under test. Resonant fluorescence emissions from the test material are coupled into a photodiode that converts the radiation to an electrical current. The current is amplified in an amplifier system, which may comprise first and second stage amplifiers. The first stage amplifier may be a current-to-voltage converter. The gain of the first amplifier stage is reduced when the light source is gated ON and increased when the light source is gated OFF. The source impedances on the inputs of the first stage amplifier are balanced so the effective input resistance and capacitance are substantially the same when the amplifier is switched between low gain and high gain to minimize effects of charge injection from the switches on the amplifier response time. The output of the first amplifier is coupled to the second stage amplifier which may have programmable offset and gain digitally controlled in response to control signals. The output of the second stage may be digitized by an analog-to-digital converter and analyzed. The pulse control signal and the amplifier control signals may be generated by a controller. The analog front end of a single element resonant fluorescence detection system comprises an excitation circuit and a single photodiode connected to a photodiode amplifier. The analog front end (AFE) establishes a maximum performance of the system with regards to bandwidth, signal-to-noise ratio, linearity, and dynamic range. The output comprises a decaying exponential voltage that is the analog of a resonant fluorescence signal with minimal distortion due to instrumental artifacts and overlapping spectra. Fluorescence is the emission of electromagnetic radiation or light immediately after absorbing incident radiation or light. The resonant fluorescence phenomenon occurs when the spectra or wavelength of the emission overlaps the incident or excitation source wavelength. The delay time between absorption and emission is minimal. The fluorescence lifetime or 1/e value is the time that is equivalent to 36.8% of the initial intensity value of the fluorescing signal. The excitation circuit is designed to drive a single light emitting diode (LED), or multiple LEDs, with sufficient power and with a sufficiently short duration or pulse width. The input of the excitation circuit may be designed to be compatible with CMOS logic levels such that a single general purpose I/O pin from a microcontroller or DSP may control the turn-ON and turn-OFF timing of the LED. A typical excitation pulse width may be in the range of 1 millisecond. A photodiode is biased to operate in the photoconductive mode and connected to a two-stage amplifier. The first stage amplifier may be a transimpedance amplifier designed to convert the photodiode current to a voltage. The second stage amplifier may be a non-inverting amplifier that further amplifies and conditions the photodiode current. The digital input signal to the excitation circuit also drives or gates analog switches, which substantially reduces the gain of the transimpedance amplifier when the excitation LED is ON or radiating. Reducing amplifier gain as a function of excitation source status decreases non-linearity due to amplifier saturation or cross-talk from the excitation source, crosstalk being an undesired effect of overlapping spectra. The spectral power density (SPD) of the excitation source is multiple orders of magnitude higher than the SPD of the fluorescing material emission. A saturated amplifier may substantially degrade the bandwidth and linearity of the system when detecting materials with short lifetimes, thus impairing, complicating or increasing cost of authentication system and method. Further details are described relative to the figures that follow. FIG. 1 illustrates a block diagram of resonant fluorescence detection system 100. System 100 may be utilized to determine if a monitored material possesses a particular taggant which is configured with a composition that fluoresces when irradiated with a particular wavelength of light. Microcontroller 102, in response to control steps programmed within, provides a pulsed signal 109 with a predetermined pulse width (e.g., 1 millisecond) to light emitting diode (LED) driver 103. LED driver 103 is configured to turn ON LED 104 (pulse signal 121) for a time period equal to the predetermined pulse width. When LED 104 turns ON, a pulse of light 114 excites tagged substrate 101 (an example of the aforementioned material possessing a taggant). In response to the pulse of light 114, tagged substrate 101 fluoresces after absorbing the incident light 114, thereby producing resonant fluorescence emission 113. Photodiode (PD) 105 is configured as a photoconductive detector. Bias voltage (V bias) 111 reverse biases PD 105. When no light is received by PD 105, it conducts “dark current” under the influence of bias voltage 111. When light (e.g., 113) impinges on PD 105 it is rendered more conductive and signal current 115, proportional to the incident light 113, flows through transimpedance amplifier (AMP1) 106, which converts current 115 to output voltage Vo 112. Output voltage Vo 112 is further amplified by amplifier (AMP2) 107, thus producing output voltage Vout 118. Analog-to-digital (A/D) converter 108 converts Vout 118 to a digital signal at output 122. A/D converter 108 may also be coupled to microcontroller 102 via signal(s) 116. Microcontroller 102 receives program signals 117 and provides signal 109 and control signals 110. Control signals 110 provide digital signals used to affect offset control and gain control for amplifier 107. Pulse signal 109 is used to gate LED driver 103 and shutter driver 120. Shutter driver 120 is used via voltage-controlled analog switches within amplifier 106 (see FIG. 2), to switch resistors that balance the source impedances of amplifier 106 when it is switched between a high and low gain. FIG. 2 illustrates further details of amplifier 106. Amplifier 106 comprises operational amplifier U1 as a main gain element. Amplifier U1 is powered by positive voltage V1 201 and previously disclosed negative bias voltage V2 111. An operational amplifier, such as U1, is designed to have a very high input impedance at its input terminals (e.g., 213 and 214) and a very high open loop gain. External feedback components are used to provide the performance desired in amplifier 106. As previously described, PD 105 is reversed biased, and substantially all of the current flow (i.e., current 115) through PD 105 is forced to flow through the feedback network, comprising analog switch S2, resistor R9, resistor R3, capacitor C2, and resistors R5 and R4, by action of amplifier output voltage Vo 112. Because of the high gain between the inputs 213, 214 of amplifier U1, amplifier output voltage Vo 112 “servos” to a value necessary to maintain the voltage difference between input 213 and input 214 at essentially zero volts. The high input impedance of negative input 214 assures essentially all of the current 115 flows into the aforementioned feedback network. Since PD 105 is reversed biased, it acts much as a current source, wherein the magnitude of current that flows (i.e., current 115) depends predominately on the amount of light energy 113 impinging on PD 105, and does not depend significantly on resistor R2 or bias voltage 111. Resistors R3, R4, R9, and R5 shape the gain and, along with capacitors C2 and C3, the frequency response of amplifier 106. It can be shown that the transfer function, expressed as the ratio (Vo 112/current 115), is equal to (R4+R3(1+R4/R5)) when resistor R9 is selected by switch S2. The resistance of resistor R9 is much smaller than the resistances of resistors R3, R5, or R3. When resistor R9 is selected, essentially all of current 115 flows in resistor R9, and the aforementioned transfer function is essentially equal to the value of resistor R9. Thus, switching in resistor R9 when LED 104 is pulsed ON reduces the gain of amplifier 106. Capacitor C2 is in parallel with resistor R3 and reduces the gain of amplifier 106 as frequency increases when switch S2 is normally open. Reducing the gain of amplifier 106 during the time LED 104 is pulsed ON prevents, or at least reduces, saturation or cross-talk, since the spectral power density (SPD) of LED 104 is multiple orders of magnitude greater than the SPD of resonant fluorescence emissions 113. Switches S1 and S2 may be electronic switches, which may cause charge injection at the inputs of amplifier U1 when switching amplifier 106 between a high and low gain. If different source impedances are presented at the inputs when the gain is switched, switches S1 and S2 may thereby cause amplifier 106 to have an increased settling time. Capacitances C1 and C2 are thereby sized to be substantially equal. Capacitor C3 provides compensation for gain peaking, thus improving amplifier stability. Likewise, resistances R8 and R3 are sized to be substantially equal, and switched resistances R9 and R1 are sized to be substantially equal. Balancing the impedances at the input of amplifier U1 improves system performance when amplifier U1 is switched between high gain and low gain when LED 104 is gated ON and OFF. FIG. 3A illustrates details of one embodiment of amplifier 107, which receives output voltage Vo 112 of amplifier 106. Amplifier 107 comprises operational amplifier U2 configured as a non-inverting amplifier with a gain set by feedback resistors R17-R20 and R12. The closed loop gain of amplifier 107 may be shown to be greater than one and equal to the sum of resistor R12 and selected resistor(s) from R17-R20 divided by resistor R12. If analog switch S4 selects more than one resistor, then the resistor value used in the gain equation is the parallel combination of the selected resistors. Analog switch S4 acts to provide programmable gain in response to digital gain control signals 110 from control logic circuitry 102 (see FIG. 1). Amplifier 106 will undoubtedly have a DC offset component in its output Vo 112 that it is undesirable. By applying a DC signal to one end of resistor R11 (signal 303), the offset, as seen in output Vo 118, may be controlled to a desired value. FIG. 3A illustrates an embodiment where the offset signal 304 is provided by a programmable voltage divider network comprising resistors R10 and R13-R16 and switch S3, which may be an analog switch. Transistors T11 and T12 are configured to receive offset signal 304 and provide a voltage follower whose output (303) voltage will go from positive to negative to facilitate a bipolar offset voltage. Other circuitry for generating the compensating offset voltage to node 303 may be used and still be within the scope of the present invention. Capacitors C11 and C12 reduce the high frequency gain of amplifier 107, which may enhance the overall signal-to-noise ratio of the detector in the bandwidth of interest. FIG. 3B illustrates details of another embodiment for an amplifier 107, which receives output voltage Vo 112 of amplifier 106. Amplifier 107 comprises operational amplifier U2 configured as a non-inverting amplifier with a gain set by feedback resistors R37-R40 and R32. The closed loop gain of amplifier 107 may be shown to be greater than one and equal to the sum of resistor R32 and selected resistor(s) from R37-R40 divided by R32. If switch S5 which may be an analog switch selects more than one resistor, then the resistor value used in the gain equation is the parallel combination of the selected resistors. Switch S5 acts to provide programmable gain in response to digital gain control signals 110 from control logic circuitry 102 (see FIG. 1). Amplifier 106 will undoubtedly have a DC offset component in its output Vo 112 that it is undesirable. By applying a DC signal to one end of resistor R31 (signal 305), the offset, as seen in output Vo 118, may be reduced to a small value. FIG. 3B illustrates an embodiment where the offset signal 305 is provided by a voltage divider network comprising resistors R30 and R34 and potentiometer P1. Resistors R30 and R34 set the coarse division and potentiometer P1 provides for fine adjustment of an offset voltage plus and minus around zero volts. It is understood that programmable switch S5 may be replaced by manual switches for selecting resistors R37-R40. FIG. 4 illustrates a flow diagram of method steps 400 according to aspects of the present invention. In step 401, a pulsed light 114 of predetermined duration is directed to the material under test 101. In step 402, resonant fluorescence emissions 113 from the material 101 are received by a photoconductive device 105. In step 403, the photoconductive device's current 115 is modulated by the resonant fluorescence emissions 113 and coupled to an amplifier system, comprising amplifiers 106 and 107, which converts the current changes to voltage changes. In step 404, the gain of the first amplifier stage 106 is reduced and its input source impedances are balanced during turn ON of the pulsed light source LED 104. In step 405, the gain of the first amplifier stage 106 is increased and its input source impedances are balanced during turn OFF of the pulsed light source LED 104. In step 406, the output waveform of the second amplifier stage 107 is analyzed as a measure of the intensity of the resonant fluorescence emission. In step 407, a test is done to determine if the dynamic range of the amplifier system has been optimized. If the dynamic range has not been optimized in step 408, the offset and gain of the amplifier system are adjusted to set an optimized dynamic range. If it is determined in step 404 that the dynamic range of the amplifier system has been optimized, then in step 409 the waveform from the amplifier system is conditioned and used in an authentication algorithm validating the material under test. FIG. 5 illustrates a circuit diagram of a LED driver 103 and a shutter driver 120 useable with embodiments herewithin. Shutter driver 120 receives a pulse signal 109 from microcontroller 102. Shutter signal 119 may be used to turn ON switches S1 and S2 (see FIG. 2) from their normally open state, thereby coupling resistor R1 to ground and coupling resistor R9 between the output 112 and the input 214 of amplifier U1. Shutter signal 119 may have a rise time (essentially determined by resistor R51 and capacitor C50) different from its fall time (essentially determined by resistor R52 and capacitor C50). The rise time determines how fast amplifier 106 switches to low gain when LED 104 is turned ON and the fall time determines how quickly the gain of the amplifier is switched to a high gain after LED 104 is turned OFF. Resistor R50 limits the base current to transistor T50. LED driver 103 may be used to generate drive signal 121 that turns ON and OFF exemplary LED 104. Transistor T51 provides the drive current to LED 104 through resistor R55 when LED signal 109 is at a positive level reducing the loading on LED signal 109. Since the source impedance of transistor T51 and the resistance of resistor R55 are low, the turn ON time of LED 104 is fast. When LED signal 109 goes low to turn OFF LED 104, the capacitance of LED 104 would slow its turn OFF if transistor T52 was not present. When LED signal 109 goes low, transistor T52 will turn ON, providing a low impedance discharge path (between its emitter and collector) for the signal 121 until its value drops below the emitter-to-base turn ON threshold of transistor T52. Turning LED 104 OFF quickly reduces the delay time required before the fluorescence emission signal is ready for analysis. Returning to FIG. 1, an application of system 100 is to provide a signal from objects possessing a particular taggant for purposes of identification. For example, tagged substrate 101 may be an item of value or critical source of information such as labels, product packaging material, a bank note or a series of bank notes that pass by system 100 on a conveyor system (not shown) during manufacturing, warehousing, sorting, or retail operations. Tagged items may also include coins, stamps, and consumable medical supplies, such as reagent and glucose test strips that are targeted by counterfeiting operations or unlicensed third party manufacturing operations. As each bank note or tagged item passes by the optical components 104 and 105, system 100 is programmed to pulse LED 104. This may be performed by a communication 117 from the conveyor system, or a proximity detector such as a photointerruptor with an output conditioned to be provided to control logic 103 when each bank note is within the target area of the optical devices 104, 105. If a particular bank note possesses the specified and known taggant, it will fluoresce when irradiated by light 114, and PD 105 will then detect that florescence 113, eventually resulting in output 114 indicating the presence of the taggant. In such a system, one or more bank notes may be “scanned” and each determined to be either authentic or counterfeit. System 100 provides advantages such that this authentication process may be performed faster (the conveyor speed may be increased) while maintaining a desired level of accuracy. It is understood that any material or device with a fluorescing taggant may be monitored with such a system 100. One of ordinary skill in the art will appreciate other advantages of the embodiments described herein. Embodiments of the invention do not require optical components such as lens and optical filters to improve the signal-to-noise ratio of the emission signal or to isolate the photodiode from the excitation source when it is active, thus the increasing cost and form factor of the detector. A single digital signal or bit may be used to turn the excitation source ON and OFF while also controlling the gain of the first stage amplifier using a method that minimizes amplifier settling time due to balancing the effective charge injection of the pair of analog switches. Embodiments herein do not rely on non-linear amplifier functions, and the photodiode bias circuit does not require a voltage clamp to maintain desired performance. The effective dynamic range of the invention is sufficient with amplifier power supply rail voltages as low as +/−5 VDC. Operating from low power supply rail voltages and reduced power enables a low noise design that may be powered from existing power supply nodes contained within a host system. For example, all power to operate a device inclusive of the invention and an embedded system host may be derived from a universal serial bus (USB) port. The USB port contains a +5 VDC power source. This source may be converted to −5 VDC using an integrated circuit (not shown) designed to function as a voltage inverter or charge pump. Distributing the overall amplifier gain in two stages enables embodiments to have a faster sensor response time due to a lower measurement time constant affected by the photodiode capacitance. The photodiode appears as a current source in parallel with a capacitor. While increasing the reverse bias reduces the capacitance of the photodiode, it is desirable to keep the voltage supplies (thus bias voltage) low. Using a low gain first stage allows the resistances of the feedback to be smaller, and thus the time constant of the response time for a given photodiode capacitance may be reduced or minimized. The first stage gain (transimpedance) may be lower while the second stage gain may be higher. The direct current (DC) offset value referenced by “A” in equation (1) may be substantially eliminated in embodiments herein by adding the level shifting circuit to the second stage amplifier without increasing the response time which is determined by the impedances of the first amplifier stage and the photodiode capacitance. The second stage amplifier in embodiments is a programmable gain non-inverting amplifier with a resistor ladder to the operational amplifier negative feedback. Having a programmable gain amplifier enables an automatic gain selection algorithm to substantially extend an overall dynamic range of the system. The second stage amplifier may also include a programmable offset compensation circuit (digital potentiometer). The offset circuit may be adjusted to ensure that the analog output signal remains above ground potential. The effects of the programmable offset circuit may be integrated into an automatic gain algorithm to further maximize dynamic range for a broad set of operating conditions. The second stage may also include an active filter (e.g., capacitor C12 in FIG. 3A) to selectively attenuate or filter targeted frequency bands without affecting the bandwidth of the photodiode sensor. The transient response of the system to a unit step function in embodiments is reduced by balancing the source impedances at the inputs of the first stage amplifier that uses analog switches to switch between a high and low gain.
	summary
	description	This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2006-237927 filed on Sep. 1, 2006 in Japan, the entire contents of which are incorporated herein by reference. 1. Field of the Invention The present invention relates to a substrate cover, a charged particle beam writing apparatus, and a charged particle beam writing method. More particularly, for example, the present invention relates to an earth or “grounding” system of a substrate on which a pattern is written using electron beams, a writing apparatus, and a writing method. 2. Description of the Related Art Microlithography technology which forwards miniaturization of semiconductor devices is extremely important, because only this process performs forming a pattern in semiconductor manufacturing processes. In recent years, with an increase in high integration and large capacity of large-scale integrated circuits (LSI), a circuit line width required for semiconductor elements is becoming narrower and narrower. In order to form a desired circuit pattern on these semiconductor devices, a master pattern (also called a reticle or a mask) with high precision is required. Then, since the electron beam technology for writing or “drawing” a pattern has excellent resolution intrinsically, it is used for manufacturing such high precision master patterns. FIG. 12 shows a schematic diagram for explaining operations of a conventional variable-shaped electron beam writing apparatus. The variable-shaped electron beam (EB) pattern writing apparatus operates as follows: As shown in the figure, the pattern writing apparatus includes two aperture plates. A first or “upper” aperture plate 410 has an opening or “hole” 411 in the shape of a rectangle for shaping an electron beam 330. This shape of the rectangular opening may also be a square, a rhombus, a rhomboid, etc. A second or “lower” aperture plate 420 has a variable-shaped opening 421 for shaping the electron beam 330 having passed through the opening 411 of the first aperture plate 410 into a desired rectangle. The electron beam 330 that left a charged particle source 430 and has passed through the opening 411 is deflected by a deflector. Then, the electron beam 330 passes through a part of the variable-shaped opening 421 of the second aperture plate 420, and irradiates a target workpiece 340 mounted on a stage that is continuously moving in a predetermined direction (e.g. X-axis direction). In other words, a rectangular shape capable of passing through both of the opening 411 and the variable-shaped opening 421 is written in a pattern writing region of the target workpiece 340 mounted on the stage. This method of writing or “forming” a given variable shape by letting beams pass through both of the opening 411 and the variable-shaped opening 421 is called a variable shaped beam system. Generally, a target workpiece, such as a mask substrate, is fixed to a stage by a member of a clamping mechanism, for example, on the stage in an electron beam pattern writing apparatus. When a pattern is written on the target workpiece, such as a mask substrate, by the electron beam pattern writing apparatus, an electrical conducting material comprising a layer formed on the surface of the target workpiece, such as a shading film of chromium (Cr), will be charged. If the writing is performed in such a state, the problem arises that the orbit of the electron beam irradiating for writing is bent under the influence of the electrified charge, thereby becoming impossible to write at a desired position. Alternatively, the problem arises that the electron beam becomes blurred. Then, usually, earthing (or “ground connection”) is made for the charged layer. In the conventional earthing system, some contact points are allocated on the target workpiece to couple or “connect” the target workpiece charged to ground potential. However, not only the shading film layer is charged. Since the side of the target workpiece is irradiated by a part of the electron beam, a glass substrate etc. exposed on the surface of the side of the target workpiece is also charged. As to the target workpiece, such as a mask substrate, to be written by the electron beam pattern writing apparatus, it is originally a mask blank where nothing is written. Conventionally, when writing a pattern on such a substrate, an alignment mark is provided on the stage, and alignment for writing is performed by estimating the position of the mask substrate based on the alignment mark position. However, this method is premised on that the relative position between the mask substrate and the stage does not shift. Therefore, even if the mask substrate shifts on the stage, an immediate coping cannot be performed. The position displacement can be checked only by inspecting a finished pattern after the mask substrate has been written and the processing of developing, etching, etc. has been performed. As to the position alignment method of the mask substrate in the electron beam pattern writing, the technique is disclosed that an alignment mark is beforehand formed on the mask substrate and highly precise alignment is performed between writing the first layer and writing the second layer (refer to, e.g., Japanese Unexamined Patent Publication No. 5-158218 (JP-A-5-158218)). However, in this technique, there is a problem that since the alignment mark needs to be formed on the mask substrate beforehand before writing the pattern, the number of steps is increased because the steps of writing an alignment mark on the mask substrate, developing and etching thereof are added. As mentioned above, in the electron beam pattern writing apparatus, it is desired to eliminate the influence of the electrified charge of the substrate side upon the orbit of the electron beam irradiating the substrate. Moreover, it is desired to grasp a highly precise position of the substrate even on which the mark is not specially formed. It is an object of the present invention to provide a mechanism, a method, and an apparatus for reducing the charge electrified on the side of the substrate. Furthermore, it is another object to provide a mechanism and a method of performing writing onto a highly precise position. In accordance with one aspect of the present invention, a substrate cover includes a frame-like member configured to be placed on a substrate which is to be written using a charged particle beam, and to have an outer perimeter dimension larger than a perimeter end of the substrate and an inner perimeter dimension, being a border between the frame-like member and an inner opening portion, smaller than the perimeter end of the substrate, and a contact point part configured to be provided on an undersurface of the frame-like member, in order to be electrically connected to the substrate. In accordance with another aspect of the present invention, a charged particle beam writing apparatus includes a stage configured to hold thereon a substrate attached with a substrate cover covering a whole perimeter part of the substrate and including a contact point electrically connected to the substrate, an electric conductive member configured to be electrically connected to the contact point and couple the substrate charged to ground potential, in a state that the substrate is arranged on the stage, and a writing unit configured to write a predetermined pattern onto the substrate by using a charged particle beam, in a state that the substrate is coupled to ground potential by using the electric conductive member. In accordance with another aspect of the present invention, a charged particle beam writing method includes carrying a substrate attached with a substrate cover with a predetermined mark formed thereon into a pattern writing apparatus, checking a position of the substrate by using the predetermined mark formed on the substrate cover, and writing a predetermined pattern on the substrate whose position has been checked, by using a charged particle beam. In accordance with another aspect of the present invention, a charged particle beam writing method includes carrying a substrate attached with a substrate cover that covers a whole perimeter part of the substrate into a pattern writing apparatus, and writing a predetermined pattern on the substrate attached with the substrate cover, by using a charged particle beam. In the following Embodiments, there will be described the structure using an electron beam as an example of a charged particle beam. The charged particle beam is not restricted to the electron beam, and then may be a beam using other charged particle, such as an ion beam. FIG. 1 is a schematic diagram showing a structure of a substrate cover and a substrate described in Embodiment 1. FIG. 2 shows a cross sectional view of the structure of FIG. 1. In FIGS. 1 and 2, a substrate cover 10 includes a frame 12 (an example of a frame-like member), a mark 14 for checking a position, and an earth pin 16 used as a contact point part. The frame 12 is comprised of a plate member, and the dimension of its outer perimeter is larger than the perimeter end of a substrate 101, and the dimension of its inner perimeter (that is, the border between the frame 12 and its inner opening portion) is smaller than the perimeter end of the substrate 101. In other words, as shown in FIG. 1, when the substrate cover 10 is placed on the substrate 101, it is formed so that all of the perimeter line of the substrate 101, shown by a dotted line, may overlap with the frame 12. Three earth pins 16 are electrically connected to the substrate 101. Two marks 14 are formed on the frame 12 at the diagonal positions. A substrate cover wholly comprised of a conductive material, a substrate cover which is wholly comprised of an insulating material and whose surface is coated with a conductive material, or the like is suitable for the substrate cover 10. As the conductive material, a metal material, such as copper (Cu), titanium (Ti), or an alloy thereof, is suitable, for example. As the insulating material, a ceramic material etc. is suitable, for example. FIG. 3 shows an example of a region of the substrate. In the figure, the substrate 101 includes a writing region 32 at its central part and a substrate perimeter insulating part 34 at the outside of the writing region. The substrate perimeter insulating part 34 is covered with the substrate cover 10 to be overlapped with each other. FIG. 4 is a schematic diagram describing an earthing system for coupling a substrate to ground potential according to Embodiment 1. As shown in the figure, the substrate 101 to be written includes a chromium (Cr) film 24 of a conductive material comprising a shading film layer, formed on a glass substrate 26 serving as a mask blank, and a resist film 22 thereon. A desired resist pattern can be formed by applying an electron beam onto the resist film 22. At the time of the electron beam writing the earth pin 16 is connected to the charged chromium film 24, penetrating the resist film 22. Therefore, it is desirable for the tip of the earth pin 16 to be sharp. For example, a conic tip of the earth pin 16 may be inserted into the resist film 22. When setting the substrate 101 which is attached with the substrate cover 10 to the pattern writing apparatus mentioned later and applying electron beams downward to the substrate, since the upper part of the perimeter of the substrate 101 is covered with the frame 12, the covered region can be shielded from the electron beam. Therefore, by attaching the substrate cover 10, it becomes possible to prevent the side of the substrate 101 from being charged. As to the earth pin 16, a conductive member may be separately connected to it in order to couple or “connect” the earth pin 16 to ground potential. As a result, the earth pin 16 can couple the charged electric conduction layer of the substrate 101 to ground potential. The earth pin 16 serves as an example of a contact point part. By providing the substrate cover 10 with the earthing system, it becomes possible to take the earthing system out of the pattern writing apparatus, with the substrate 101. FIG. 5 shows an example of the mark 14 described in Embodiment 1. A cross type mark as shown in FIG. 5, for example is suitable as the mark 14. The central position of the mark 14 can be specified by scanning electron beams on the vertical and horizontal lines of the mark 14 when setting the substrate in the pattern writing apparatus. It is desirable for the mark to be made of a metal material, and the mark may be formed to be convex or concave. FIG. 6 is a schematic diagram showing a structure of a pattern writing apparatus described in Embodiment 1. In the figure, a pattern writing apparatus 100 serving as an example of the charged particle beam writing apparatus includes a pattern writing unit 150 and a writing control circuit 160. The pattern writing unit 150 includes an electron lens barrel 102 and a writing chamber 103. The electron lens barrel 102 includes an electron gun assembly 201, an illumination lens 202, a first aperture plate 203, a projection lens 204, a deflector 205, a second aperture plate 206, an objective lens 207, and a deflector 208. In the writing chamber 103, an XY stage 105 is arranged. The substrate 101 serving as a target workpiece is supported by support pins 106 on the XY stage 105. The substrate 101 having already been covered with the substrate cover 10 outside the apparatus is carried into the pattern writing apparatus 100 and placed on the XY stage 105. In this case, the substrate 101 is simply supported by three support pins 106. Moreover, a spring member 212 (an example of an electric conductive member) formed of a conductive material is placed on the XY stage 105, and is electrically connected to the earth pin 16 of the substrate cover 10. Potential of the electric charge having moved to the earth pin 16 from the substrate 101 is connected to ground, through the spring member 212 and the XY stage 105. In FIG. 6, a flat spring is used as the spring member 212. Thus, by using the spring member, the impact produced by the substrate cover 10 colliding with the spring member 212 and the thrust from the spring member 212 caused by a position error can be absorbed by the spring member 212 which bends against them. As a result, it becomes possible to prevent the substrate cover 10 from unfastening from the substrate 101. Moreover, a poor electrical connection can be prevented by making the spring member 212 connect while being pressed by a compression force. In order to prevent the substrate cover 10 from unfastening from the substrate 101, it is desirable for the spring constant to be small enough to avoid poor electrical connection. While only the structure elements necessary for explaining Embodiment 1 are shown in FIG. 6, it should be understood that other structure elements generally necessary for the pattern writing apparatus 100 may also be included. It is desirable to arrange the positions of the three earth pins 16 of the substrate cover 10 to be the same as those of the support pins 106, or to be close to them. Flexure of the substrate 101 can be controlled by arranging the positions of the earth pins 16 that contact with the substrate 101 to be the same as or to be close to those of the support pins 106 that support the substrate from the backside, compared with the case of arranging them at distant positions. Generally, the substrate 101, such as a mask substrate, is fixed on the stage by using a member, such as a clamping mechanism, in the pattern writing apparatus 100. FIGS. 7A and 7B are schematic diagrams for comparing the case supported by a clamping mechanism with the structure of Embodiment 1. In the clamping mechanism shown in FIG. 7A, in order to clamp the substrate 301, it is necessary to form a structural member 300 having a certain height above the substrate 301. The substrate 301 is clamped between the structural member 300 and a spring support members 306 extending upward from a stage 305. For example, the substrate can be clamped by moving the structural member 300 or the stage 305 up and down. However, as shown in FIG. 6, since the electron lens, such as the objective lens 207, for adjusting the focus of an electron beam 200 is located close to the upside of the substrate 101, it is desired to make the thickness (height) of the member arranged above the substrate 301 be thin (low) as thin as possible. Besides, it is desirable for the structure to be small and simple as much as possible because it is arranged in a narrow space. Then, according to the structure of Embodiment 1 as shown in FIG. 7B, since the substrate 101 is simply supported by the support pin 106 and the substrate cover 10 comprised of a thin tabular frame is just placed, it is possible to make the height of the member arranged above the substrate 101 low. That is, the necessary height t1 above the substrate 101 can be formed lower than the height t2 necessary for the structural member 300 of the clamping mechanism above the substrate 301. Besides, the necessary width w1 from the edge of the substrate 101 to the edge of the substrate cover 10 can be shorter than the necessary width w2 from the edge of the substrate 301 to the edge of the structural member 300 of the clamping mechanism. Moreover, in the case of using the substrate cover 10, since it is enough to just put the substrate covered with the substrate cover 10 on the support pin 106 as a complete arrangement, no complicated structure for making the substrate move up and down, such as the clamping mechanism, is necessary. Though the substrate 101 is simply supported in the structure of Embodiment 1, what is necessary is to make the contact surface between the support pin 106 and the substrate 101 have a friction coefficient durable for the movement acceleration of the XY stage 105. FIG. 8 is a flowchart showing main steps of the writing method according to Embodiment 1. In the figure, a series of steps, such as a carry-in step (S102), a position check step (S104), and a writing step (S106), are executed. In S102, as a carry-in step, the substrate 101 attached with the substrate cover 10 is carried into the pattern writing apparatus 100. Since the substrate cover 10 is not the internal structure of the pattern writing apparatus 100, it has the merit of capable of taking it outside the apparatus and of being easy to have maintenance. In S104, as a position check step, the electron beam 200 scans the mark 14, measures the position of the mark, and checks the position of the substrate 101 by using the measurement result. Since the substrate cover 10 is arranged on the substrate 101, even when the substrate 101 shifts on the XY stage 105, the substrate cover 10 moves unitedly with the substrate 101. Therefore, it is possible to prevent deviation of the relative position between the mark and the substrate which is generated in the conventional case of providing the mark on the stage. Thus, by using the mark 14 formed on the substrate cover 10 united with the substrate 101, since the relative position with respect to the mark does not change even when the substrate 101 shifts from the XY stage 105, the accurate position of the substrate 101 can be specified. Therefore, it is possible to check whether there is a position displacement of the substrate 101 or not. Since the existence of the position displacement of the substrate 101 can be checked at the time of writing, to eliminate a substrate having a pattern error can be executed even during the processing, compared with the conventional case in which the position displacement can be checked only after the processing of development, etching, etc. As a result, a useless step can be reduced. Although one mark may be sufficient as the mark 14, it is more desirable to prepare two or more marks in order to accurately grasp the position of the substrate 101. It is especially preferable to provide the marks diagonally as shown in FIG. 1. In S106, as a writing step, after checking the position of the substrate 101, a desired pattern is written by applying the electron beam 200 onto the writing region 32 of the substrate 101. Detailed flow of the writing step will be described below. The electron beam 200, being an example of a charged particle beam, emitted from the electron gun assembly 201 is collected by the illumination lens 202 to irradiate the whole of the first aperture plate 203 having a rectangular opening, for example. This shape of the rectangular opening may also be a square, a rhombus, a rhomboid, etc. At this point, the electron beam 200 is shaped to be a rectangle. Then, after having passed through the first aperture plate 203, the electron beam 200 of a first aperture image is guided by the projection lens 204 to reach the second aperture plate 206. The position of the first aperture image on the second aperture plate 206 is controlled by the deflector 205, and thereby the shape and size of the beam can be changed. After having passed through the second aperture plate 206, the electron beam 200 of a second aperture image is focus-adjusted by the objective lens 207 and deflected by the deflector 208, to reach a desired position on the target workpiece 101 placed on the XY stage 105 which is movably arranged. The inside of the electron lens barrel 102 and the writing chamber 103 wherein the XY stage is arranged is exhausted by a vacuum pump (not shown), and controlled to be vacuum atmosphere whose pressure is lower than atmospheric pressure. As mentioned above, by applying the electron beam 200 onto the substrate 101 in the state of the whole perimeter part of the substrate 101 being covered with the substrate cover 10, the electron beam to reach the side of the substrate 101 can be shielded by the substrate cover 10. Accordingly, electrification to the side of the substrate 101 can be prevented. Therefore, deviation of the beam orbit caused by the electrified charge on the side of the substrate side can be prevented. Therefore, since the substrate cover is attached to the substrate and moves unitedly with the substrate, the accurate position of the substrate can be checked. As a result, a poor substrate wherein displacement has been generated can be eliminated at the early stage. As the position check step mentioned above, the position of the mark may be measured not only before the writing start but also after the writing. Moreover, since the writing is executed for each predetermined unit (for example, a writing stripe), it is preferable to measure the mark position for each of this writing unit to check the position. FIG. 9 is a schematic diagram showing a structure of the substrate cover and the substrate described in Embodiment 2. According to Embodiment 2, the height position of the mark 14 of the substrate cover 10 is structured to be the same as that of the front surface of the substrate 101, i.e., the surface height of the resist film 22. In FIG. 9, there is provided a downwardly projecting thick part at the outer part of the frame 12, and the height position of the mark 14 is adjusted by using this thick part. Thus, by making the height position of the mark 14 be the same as that of the surface of the substrate 101, it becomes possible to grasp the position of the substrate 101 more highly accurately based on the value of the measured mark position. The thick part at the outer part of the frame 12 may be formed over the whole perimeter of the frame 12, or may be formed only at the position of the mark 14. Moreover, the thick part and the frame 12 may be formed unitedly, or may be connected each other after being formed separately. Other structure is the same as that of Embodiment 1. FIG. 10 is a schematic diagram showing a structure of the substrate cover described in Embodiment 3. In Embodiments 1 and 2, there is provided the structure in which the earth pin 16 and the main part of the frame 12 are electrically connected. In Embodiment 3, insulating members 18 are arranged respectively at the three positions of the earth pins 16 of the frame 12, and each earth pin 16 is arranged in each insulating member 18 to make the earth pin 16 be insulated from the main part of the frame 12. The earth pin 16 and the frame 12 are separately coupled to ground potential respectively. This structure enables to know whether the electrically charged main body of the frame 12 was coupled to ground potential, or the charged Cr layer was coupled to ground potential through the earth pin 16. This method makes it possible to control each electric potential individually. As to the spring member 212, when arranged in the pattern writing apparatus 100, it is enough to prepare the spring members 212 for the earth pins 16 and for the frame 12 main body. Other structure is the same as that of Embodiment 1. FIG. 11 is a schematic diagram showing a state where the substrate attached with the substrate cover is carried into the pattern writing apparatus described in Embodiment 4. In the above Embodiments 1 to 3, when the substrate 101 attached with the substrate cover 10 is arranged in the pattern writing apparatus 100, an earth connection is made by the spring member 212 formed of a flat spring member. In Embodiment 4, as shown in FIG. 11, an earth connection is made by a spring member 214 formed of a spiral spring member. Thus, it is acceptable to use a spring member other than the flat spring member, for making an earth connection. Other structure is the same as that of Embodiment 1. The embodiments have been described with reference to the concrete examples. However, the present invention is not limited thereto. For example, in each Embodiment mentioned above, a spring member, such as the spring member 212 and the spring member 214, is used to make an earth connection, but it is not restricted thereto. A member capable of making an earth connection will be applied. While the parts or units not directly necessary for explaining the present invention, such as the structure of the apparatus and the control methods, are not described, it is possible to suitably select and use some or all of them when needed. For example, though the description of the structure of the control unit for controlling the pattern writing apparatus 100 is omitted, it should be understood that required structures of the control unit can be appropriately selected and used. In addition, any substrate cover, charged particle beam writing apparatus, and charged particle beam writing method that include elements of the present invention and that can be appropriately modified by those skilled in the art are included within the spirit and scope of the present invention. Additional advantages and modification will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
048184756	description	DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified block diagram for a simplified boiling water reactor 2 of prior art configuration. Reactor 2 includes a reactor pressure vessel 4 which has disposed therein a reactor core 6. The reactor core is covered by cooling water 8 which is supplied and circulated during normal operation. Normal operation can be simply summarized. As shown in FIG. 1, steam from the reactor vessel 4 is input to turbine 24. Turbine 24 is coupled to generat or 30 through the main rotating shaft 32 of turbine 24. The power output of generator 30 is coupled to the main station power supply 50. Exhaust of turbine 24, in the form of wet steam, is fed to condenser 44. Condensate from condenser 44 flows to the suction of condensate pump 18. Condensate discharged from condensate pump 18 is fed to the suction of feed pump 16. Feed pump 16 elevates the head of the feedwater to exceed reactor vessel pressure and supplies feedwater through feedwater line 38 back to the reactor vessel 4, thereby completing the steam cycle. When a loss-of-coolant inventory accident occurs, the reactor vessel is depressurized through depressurization valve 90 and vent line 92 to suppression pool 10. When depressurization has progressed to an appropriate degree, reactor 2 becomes cooled by the gravity injection of suppression pool coolant through check valve 94. Backup cooling is conventionally provided using power from a main power supply 50 to power feedwater (cooling) system 200. The emergency power may be provided from either the main coupled generator 30, the grid, or from diesel generators (not shown). FIG. 2 is an illustration of an improved emergency core cooling system according to one embodiment of the invention. FIG. 2 shows the conventional prior art boiling water reactor 2 having the emergency core cooling system according to one embodiment of the invention. FIG. 2 shows the conventional prior art boiling water reactor 2 having the emergency core cooling system featuring a low pressure coolant injection capability. A steam output from the turbine-generator 24 inputs to condenser 44. A condensate storage tank 41 supplements the inventory of condensate within the condenser 44 to replenish water inventory within condenser 44 whenever reactor steam supply becomes isolated. Output of condenser 44 is coupled to condensate pump 18. The output of condensate pump 18 has two separate destinations. The first conventional destination is to the suction of feed pump 16. The second destination is to the upstream side of a check valve 120 on a bypass line 22. The output of check valve 120 is coupled to the interior of reactor vessel 4. The bypass line 22 and check valve 120 may be configured to tie into feedwater line 38 or into a dedicated injection inlet to vessel 4. During normal operation, pressure in the reactor vessel 4 exceeds pressure at the output of condensate pump 18. Check valve 120 in line 22 prevents reverse flow from reactor vessel 4 toward condensate pump 18. This condensate pump 18 and feed pump 16 function normally in series to provide conventional feedwater flow. As further shown in FIG. 2, an auxiliary generator 34 is coupled to a main shaft of the coupled main generator 30 and turbine 24. The output of auxiliary generator 34 is coupled to an input to power supply 36. Power supply 36 is dedicated to driving pump motor 28. This condensate pump 18 has a dedicated power supply from generator 34. Pump motor 28 drives condensate pump 18 using power generated by auxiliary generator 34. Power supply 36 is normally directly connected to motor 28 without any intervening switching or bus transfer required. Auxiliary generator 34 provides normal short-term-response power for motor 28 when condensate pump 18 is used during normal initial core cooling. Auxiliary generator 34 converts the rotational energy of main turbine and main coupled generator into electric power, including converting the spindown momentum during loss-of-coolant inventory accidents. Operation of the condensate pump 18, bypass line 22 and check valve 120 during a loss-of-coolant inventory accident can be understood. Specifically, and even though main generator 30 is inoperative and completely decoupled from the main station power supply 50, auxiliary generator 34 will continue to generate power from the available and coupled spindown momentum. This being the case, condensate pump 18 will continue to operate. Discharge of the condensate pump 18 will temporarily be interrupted. Such interruption will occur because main feed pump 16 will likely be offline because of the power failure. Thus condensate pump will output its discharge head to check valve 120. Because of the loss-of-coolant accident pressure in the reactor will fall. When pressure in the reactor reaches a pressure below the shutoff head of the condensate pump, the flow of coolant into the reactor will resume. Such flow will be from the discharge of the condensate pump 18, through line 22 and check valve 120, and directly into the reactor vessel. As will be hereafter emphasized, this flow of coolant to the reactor replacing lost coolant will occur much earlier than has heretofore been possible; it will occur from the moment when reactor pressure falls below the shutoff head of condensate pump 18. I have preferably used the resident condensate pump 18 to supply coolant to the reactor vessel 4. The reader will realize that in some nuclear reactor designs it may be desirable to have a separate dedicated low pressure injection pump 48 and driving motor 58 to accomplish this function. Such an embodiment is illustrated in FIG. 3. FIG. 3 is a coolant flow of an alternative embodiment of the invention. Low pressure injection pump 48 intakes coolant derived from condenser 44 and discharges the coolant through injection line 23 and injection check valve 21 into reactor vessel 4. It is required that low pressure injection motor 58 and pump 48 be signalled and brought on line responsive to conventional prior art reactor water level indicators. Auxiliary generator 34 provides power to motor 58 driving low pressure injection pump 48. While this alternative embodiment represents potential cost increases resulting from the addition of a new pump/motor unit and its connecting piping, there are potential major net cost reductions to the resultant overall system depending on the sizing of pump/motor unit 48/58. Operation of the embodiment of FIG. 3 is easily understood. A bypass low pressure coolant injection (LPCI) line 23 is provided. Line 23 incorporates a normally-closed LPCI flow injection valve 21 located upstream of an LPCI injection nozzle. LPCI injection nozzle is positioned on the reactor vessel 4 and communicated to the discharge side of LPCI pump 48. Under certain conditions, a loss-of-coolant accident, loss-of-station power, loss-of-coolant inventory accident, or another such emergency core cooling event could (in worst-case scenario) cause loss of the normal feedwater supply to the reactor. Reactor 4 through conventional prior art sensors senses a loss-of-coolant inventory condition and begins depressurization through sequentially-opened depressurization valves 90 once the water level inside the reactor 4 reaches the Level-1 level. When reactor 4 has depressurized to approximately the pump shutoff head developed by pump 48, the bypass line injection valve 21 opens to admit pumped condensate to the reactor. As the reactor depressurizes further, the LPCI flow tends to increase--this effect being caused by the characteristic of centrifugal pumps to provide increased volume throughout as pump back-pressure decreases--but may (depending on LPCI motor controls) be partially offset by the reduction in rotational speed (referred to as coastdown or spindown) of the main turbine-generator as a consequence both of turbine-generator bearings and windage losses as well as energy removed for pumping. For the most-challenging design accident scenarios, the depressurization from reactor normal conditions (1020 psig) down to the pressure at which LPCI flow injection can begin (600 psig or lower, depending on design optimization for LPCI pump 48) takes approximately one minute. Thereafter, LPCI flow into the reactor vessel begins. For the same challenging accident scenarios, the reactor depressurizes over the next four minutes down to a pressure at which water from suppression pool 10 begins flowing into the reactor. Referring back to FIG. 1 for conventional simplified boiling water reactors, the main turbine-generator would supply power to the main station (site) power supply. The site power supply 50 would supply power to feed pump 16 and to a condensate pump 18 during normal operations. For backup coolant inventory replenishment, grid power sources and/or non-safety-grade diesel generators, as available, are coupled via bus transfer to the feed pump and to the condensate pump to provide alternate power for the requisite pumping during a loss-of-coolant inventory accident. It will therefore be realized the power supply for backup emergency cooling according to the disclosed invention is inherently more reliable over the duration of power supply need, because of the avoidance of requiring start-up of diesel generators and/or because of the avoidance of bus transfers from electrical buses that are subject to externally-caused power interruptions. As shown in FIG. 2, the emergency coolant injection power supply for the low pressure coolant injection capability is furnished by dedicated, unswitched normal and emergency power from auxiliary generator 34 to the condensate pump 18. The auxiliary generator 34 also can supply normal and emergency power to selected other emergency core cooling system loads 60. During normal operation, the feed pumps, which draw substantial power (on the order of several megawatts) are fed from the site power supply 50 over normal lines to a power input to drive motor 26 of feed pump 16. According to the invention, it is possible to couple dedicated normal and short term emergency power from the auxiliary generator 34 over a power supply line to an input to a plurality of individual motors and their associated coolant injection pumps. For example, where feedwater is used to power the recirculation flow in a boiling water reactor--such as in the case of a feedwater-driven jet pump recirculation system BWR--the feature of having short-term continued feedwater injection capability is highly desirable. The invention brings about the capability of being able to maintain coolant forced circulation in such reactors over the short term of depressurization experienced in a loss of coolant accident. FIG. 4 is a graph that depicts the reactor depressurization curve for a conventional simplified boiling water reactor that uses a venting system together with a gravity-driven cooling system. This same graph also depicts improved system in accordance with the invention. This improved system uses a venting system, a gravity-driven system, and short term low pressure coolant injection capability to inject condensate into the reactor vessel during the depressurization phase, at the early part of a loss-of-coolant inventory accident. As shown in FIG. 4, time t.sub.0 represents the time at which an event requiring emergency core cooling occurs. Before and until time t.sub.0 the pressure in the reactor vessel will be approximately 1000 psig at the point in time when venting is initiated. According to the prior art boiling water reactor gravity-driven cooling system, the reactor vessel would be depressurized down to about 30 psig over approximately a 10-12 minute interval using the venting system. The improved performance of this invention is illustrated in FIG. 4 in broken lines. Using the protocol of either FIG. 2 or FIG. 3, condensate is pumped back into the reactor vessel using the emergency power supply system and condensate (low pressure) pumps. Such introduction of condensate occurs when the reactor/injection vessel pressure reaches the shutoff head for the condensate (low pressure) pump which is around 600 psig. With this earlier induced coolant flow, it is important to realize the depressurization curve for the reactor vessel can be accelerated. Specifically, the reactor vessel can be depressurized down to 30 psig at some t.sub.2 which is several minutes earlier than for the conventional system. The injection of coolant and the more rapid resulting depressurization facilitates a reduction in the volume of coolant required in the TAF to Level-1 zone and in the suppression pool. This reduced depressurization also permits a reduction in the number of valves and the venting capacity required for the depressurization system. The water provided by the LPCI pump (per FIG. 3 embodiment) or by the condensate pump (per FIG. 2 embodiment) using the spindown energy of the turbine generator during the four-minute period provides reliable, low cost, short term emergency coolant. This coolant undergoes injection with considerable margin relative to the volumetric inventory between TAF and Level-1. The reader will understand further that the total volume of water in the reactor is subjeot to reduction. This reduction occurs for at least the following three reasons. First each LPCI pump (condensate pump) is producing nominally 50% rated feedwater flow. Second, the depressurization period necessary to bring the vessel pressure down to 30 psig, over which reactor inventory depletion occurs by venting coolant through the depressurization valves, is limited to four minutes as compared to 10 to 12 minutes with no injection. Finally, multiple LPCI and/or condensate pumps are available to recharge the reactor with coolant. As earlier discussed, only one minute of rated feedwater flow is necessary to supply the requisite water volume. The volume represented in the conventional SBWR reactor between TAF-and-Level-1 can be correspondingly reduced. Thus, the resulting flow rate (50%) times the duration (4 minutes) provides a minimum of 2 minutes of rated-power-flow even assuming that only one LPCI pump (or condensate pump) is available. It is noted that during the initial moments of an event requiring emergency core cooling, prior to start of LPCI injection, the recirculation line customarily provided on such pumps recycles a small portion of discharge flow back around to pump suction. (This type of piping configuration line is a conventional engineering practice which prevents unwelcomed overheating of deadheaded pumped fluid). According to the invention, the amount of required injection flow is thus seen to be small relative to the BWR/3 through the BWR/6 model BWR designs that require coolant flow injections uninterrupted for indefinitely long time periods. Since the integrated pumping energy demand over the period of interest--said to be no longer than five minutes even under worst-case event scenarios--is demonstrably small, the invention is able to use the spindown energy of the main turbine-generator as an assured, virtually cost free source of emergency power. The turbine-generator of the typical BWR power station, separated from its load, typically requires no less than 40 minutes to spindown to speeds at which the turbine-generator turning gear cuts-in to maintain slow revolutions on the turbine-generator shaft. This coastdown is produced by the combination of frictional drag from bearings, plus windage losses by the turbine-generator blades spinning in the low pressure (typically 2-3 ins.Hg) maintained by the main condenser. For example, for a 600 MWe turbine-generator, approximately 1.5 MWe-equivalent drag is produced at the 1500 rpm (50 cycle)/1800 rpm (60 cycle) initial free-rotation speed. (Actually, when the turbine-generator is separated from its load, residual steam in the turbine-generator casing momentarily causes the turbine-generator to go into an overspeed mode, so that coastdown actually begins from a still higher rpm.) The energy extracted by the shaft-coupled auxiliary generator(s) and consumed by the electrically-coupled LPCI and/or condensate pumps amounts to the same order-of-magnitude rate as for the turbine-generator bearing and windage losses. Thus, the 4 or 5 minutes integrated energy drawn by the LPCI and/or condensate pumps can be seen to be modest relative to the integrated energy available from the turbine-generator coastdown. In the event certain specific applications of the invention were to find an insufficiency of rotational energy in the turbine-generator system to accomplish the full desired short-duration coolant injection pumping burden, a properly sized flywheel can be added to the turbine-generator system to provide the additional rotational energy required. It is within the scope of the invention to provide emergency power from the auxiliary shaft-coupled generator to supply short-term power to the adjustable speed drives of the feedwater pumps which are located downstream from the condensate pumps in the feedwater train. As a result, feedwater flow can be continued into the reactor under loss-of-offsite-power events in which the reactor feedwater injection lines do not become shut closed. Under these conditions, the continued supply of feedwater could be critical to avoiding violation of certain safety-limit margin conditions. As one example, if the core recirculation flow for the SBWR reactor were of the forced-circulat ion type based on feedwater-driven jet pumps, then supplying drive power to the feedwater pumps in the manner described by this invention would produce the cited advantage. It is also possible to use the auxiliary generators to power other existing, or new, emergency core cooling loads. These loads can include opening or closing certain motor-operated valves, or providing power for forced injection of coolant from the elevated suppression pool into the reactor vessel to accelerate depressurization of the reactor vessel. It is also possible to conserve the useful energy of the short term power supply, for example, by not switching the LPCI pump on (in the FIG. 3 embodiment) until the reactor vessel pressure has fallen below the shutoff head for the LPCI pump. Further, it is also possible to use feedwater pumps and condensate pumps either in combination or in a staggered timing relationship depending on design constraints. It is also possible within the scope of the invention to use separate dedicated LPCI pumps and injection lines that tie into the normal condensate line. It is also within the scope of the invention to couple power from the auxiliary generator to a main station transfer bus. It is possible to supply during normal operation the condensate pump with power derived directly from the main coupled generator feeding this main transfer bus. After occurrence of a loss-of-coolant inventory accident, the main bus could switch so that power would be provided from the auxiliary generators. This approach obviously lacks the higher reliability feature of those embodiments not requiring any switching. Other changes and modifications to the disclosed embodiments other than the foregoing may be made as will be readily apparent to those skilled in the art within the scope and spirit of the invention. Accordingly, it is applicants' intention that the invention be therefore limited only by the appended claims.
	abstract	The present invention describes a method for fabricating an x-ray mask tool which can achieve pattern features having lateral dimension of less than 1 micron. The process uses a thin photoresist and a standard lithographic mask to transfer an trace image pattern in the surface of a silicon wafer by exposing and developing the resist. The exposed portion of the silicon substrate is then anisotropically etched to provide an etched image of the trace image pattern consisting of a series of channels in the silicon having a high depth-to-width aspect ratio. These channels are then filled by depositing a metal such as gold to provide an inverse image of the trace image and thereby providing a robust x-ray mask tool.
063339579	abstract	A tool kit for adjusting the angular orientation of water rods about respective axes in a nuclear fuel bundle includes a washer wrench, socket, orientator wrenches, orientator gauges and an orientator cap. The washer wrench has opposed jaws having parallel surfaces and reliefs at junctures between the surfaces and the base of the jaws to inhibit rounding off corners of tie bars connected to the water rods. The socket has a corresponding D-shaped recess as the tie bar ends to facilitate rotational adjustment thereof. Orientator wrenches have witness notches for aligning the flats of the tie bars. The orientator gauges comprise a series of gauge bodies each having a pair of axially parallel openings with stepped margins to the openings such that one opening is axially offset from the margin defining the entrance to the other opening. The orientator cap has complementary-shaped openings for receiving the upper ends of the tie bars to maintain the orientation of the tie bars and water rods during shipment of the fuel bundle.
	summary
047479981	abstract	A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.
045487847	description	The power control system of the present invention applied to a pressure tube type nuclear reactor is now explained below. FIG. 1 shows a cross-sectional view of the nuclear reactor. A number of pressure tubes 2 are arranged in the nuclear reactor core tank 1. While not shown, all of the pressure tubes 2 have a calandria tube and fuel assemblies. In order to measure a power of the reactor, neutron detectors 3 are mounted between the pressure tubes 2 at several points in a heavy water moderator region 4 in the reactor core tank 1. Power flattening control rods 5 for averaging the power distribution of the reactor and automatic power control rods 6 for automatically controlling the power level of the nuclear reactor based on the measurement by the neutron detectors 3 are disposed in the nuclear reactor. FIG. 2 shows a longitudinal sectional view of the nuclear reactor. In addition to the power flattening control rods 5 and the automatic power control rods 6 described above, a safety rod 7 for emergency shutdown of the nuclear reactor in case of an accident of the nuclear reactor is provided as a control rod. The control rods 5 and 6 and the safety rod 7 are all inserted between the pressure tubes 2 to reduce the power. Signals from the detectors 3 uniformly distributed within the heavy water moderator 4 are summed and averaged in a summing and averaging circuit 8 and calibrated in a calibration circuit 9 with a thermal output of the nuclear reactor determined by a periodic thermal heat balance calculation. In a normal operation, this signal is compared in a sampling adjuster 10 with a preset nuclear reactor power signal A requested by an operator of the nuclear reactor. Assuming that the former signal is positive and the latter signal is negative, when a differential signal amplified by an amplifier 17 is positive, a control rod drive circuit 11 produces a control rod withdrawal signal so that the automatic power control rods 6 are withdrawn from the reactor by a control rod drive mechanism 13 and a control rod drive motor 12 until the signal reaches zero. If the difference between the positive signal and the negative signal is negative, the automatic power control rods 6 are inserted into the reactor so that the power level of the nuclear reactor is automatically controlled to the predetermined level. If the safety rod 7 drops into the nuclear reactor tank 1 by some reason, for example, by an improper operation or a failure in the control rod drive mechanism 13, the signal of the summing and averaging circuit 8 which sums and averages the signals from the nuclear detectors 3 becomes smaller than the signal A (e.g. 100% output) preset by the operator of the nuclear reactor. A difference between the averaged measurement of the nuclear detectors and the preset level A is compared in a comparator 15 with a critical signal level B (e.g. 5% output) for a power reduction which is also preset by the operator of the nuclear reactor. Only when the difference is larger than the preset level B, the control rod withdrawal protection signal circuit 14 produces a control rod withdrawal protection signal to prevent the withdrawal of the automatic power control rods 6. In the prior art control system which has no such control rod withdrawal protection means, the drop of the safety rod is compensated by the withdrawal of the automatic power control rods 6 so that the power level is automatically recovered to the original 100% power level. FIG. 3 shows a change in the nuclear reactor power and a change in position of the automatic power control rods 6. In FIG. 3, it is assumed that an accident of the drop of the control rod such as the safety rod into the nuclear reactor takes place at a time zero (second). In this case, the nuclear reactor power drops to a 75% power level in two seconds from the occurrence of the accident. As a result, the average of the signals from the detectors 3 shown in FIG. 3 becomes smaller than the preset level A (100% output) for the power of the nuclear reactor and the automatic power control rods 6 are withdrawn from the nuclear reactor 0.5 second after the occurrence of the accident due to a time delay in the calibration circuit 9 so that the power recovers to its original level (100% output) in approximately ten seconds. However, the power distribution in the nuclear reactor is not flattened in this case and the maximum linear heat generating rate which is no more than 17.5 kw/ft in order to prevent the fuel in the nuclear reactor from becoming molten and the minimum critical heat flux ratio which is no less than 1.9 in order to prevent the cladding from being burnt out change. Consequently, when the control rod (including the safety rod) other than the optimum designed power flattening control rod is inserted into the nuclear reactor, the power distribution results in a large distortion as shown by a broken line in FIG. 4, in which the area at which the drop accident has taken place shows a low power distribution and the other areas show a high power distribution. As a result, the heat limitations such as the maximum linear heat generating rate and the minimum critical heat flux ratio exceed the design limits at the high power areas and the fuel may become molten and fail. FIG. 5 shows changes in time of the maximum linear heat generating rate and the minimum critical heat flux ratio as the control rod drops. As a result of the reduction of the power by the drop of the control rod such as the safety rod 7, the maximum linear heat generating rate becomes small and the minimum critical heat flux ratio becomes large for about one second after the accident. The power thereafter increases to compensate for the reduction of the power in the low power area as shown in FIG. 3 so that the maximum linear heat generating rate in the high power area changes largely while the minimum critical heat flux ratio changes in a small amount. Those values overshoot and undershoot, respectively, approximately nine seconds after the accident, and when the nuclear reactor output recovers to the 100% power level, the maximum linear heat generating rate assumes a value of 21 kw/ft and the minimum critical heat flux ratio assumes a value of 1.5. The reason why those values are larger and smaller than the pre-accident values 17.5 kw/ft and 1.9, respectively, is because the power distribution is remarkably distorted by the drop of the control rod. On the other hand, when the withdrawal of the control rod is protected in accordance with the embodiment of the present invention, the nuclear reactor power and the position of the automatic power control rods change as shown in FIG. 6 when the control rod drops into the nuclear reactor. In FIG. 6, as the control rod drops, the power is reduced from 100% power to 75% power in a short time (approximately two seconds). However, since the amount of reduction (25%) is larger than the preset amount B (5% power), the automatic power control rods 6 are withdrawn only by the amount corresponding to the time delay in the comparator 15 and the calibrator 9, when the withdrawal of the automatic power control rods 6 is protected by the control rod withdrawal protection signal. As a result, the recovery of the nuclear reactor power level stops at 80% power level. Consequently, even if the power distribution of the nuclear reactor is distorted as shown by the broken line in FIG. 4 by the drop of the control rod, the power level recovers only to as much as 80% and hence the maximum linear heat generating rate for the heat factors rises only to 16 kw/ft as shown in FIG. 7. Similarly, the minimum critical heat flux ratio falls only to 2.1. Since those values satisfy the limitations of no more than 17.5 kw/ft and no less than 1.9, the integrity of the fuel is maintained. The preset level B is determined taking an external disturbance of the nuclear reactor into consideration because it is necessary that the automatic power control fully functions for the external disturbance which may occur during a normal operation of the nuclear reactor and which does not disturb the operation of the nuclear reactor. Thus, an effective value for the preset level B is 5%. With such a preset level, the withdrawal of the control rod is not prevented by the external disturbance, provided that an abnormal condition of the control rod per se such as the drop of the control rod does not take place. If a response value of the dropped control rod is so small that the power changes only as much as five percent when the control rod drops, the power level recovers to the original 100% power level by the withdrawal of the automatic power control rods. In this case, however, since the response value of the dropped control rod is small, the distortion in the power distribution when the control rod drops is small and the integrity of the fuel is maintained. While the safety rod was assumed as the control rod which may drop in the description set forth above, it should be understood that the control rod may be the power flattening control rod or liquid poison. The means for automatically controlling the power level of the nuclear reactor may be concentration control of liquid poison included in the heavy water moderator. In this case, the function of a liquid poison remover may be stopped when the power level is lowered below the preset level B.
	summary
050892215	abstract	An improved spacer is disclosed which contains an Inconel grid and a Zircaloy surrounding band. The Inconel grid can be fabricated from the extremely thin and highly elastic spring metal utilizing a modification of a prior art cell construction that includes paired inwardly bent vertical spring legs with cantilevered and rod encircling upper and lower arm pairs. The spring legs extend at spaced apart locations between the upper and lower arm pairs and have a medial spring rod contacting portion for biasing the rods into stops on the rod encircling arm pairs. The springs at the upper and lower ends are provided with spring dimple stops to prevent over stressing of the spring during assembly or handling of the fuel bundle into which the spacer is incorporated. The rod encircling arm pairs have an offset from center where the two arms meet at their distal ends to complete encirclement of the rods. This offset from center enables the cells to be fastened in cell pairs at their respective embracing arms. The cell pairs can in turn be manipulated as a unit to define the necessary types of spacer grids required for any particular grid construction. A preferred grid construction for a ten by ten fuel rod matrix is disclosed including a grid filling all rod lattice positions for the bottom of a fuel bundle, a grid enabling the placement of a water rod of varying diameter, and finally a grid defining missing lattice positions for overlying partial length rods and permitting upward venting of steam with minimum pressure drop. An all Zircaloy band is disclosed for surrounding containment of the Inconel grid. The band consists of two or four segments. Apertures are provided in the band at the corners, and portions of the corner Inconel cells project into these apertures, keying the Inconel grid to the Zircaloy band. The band is welded into continuous encircling relation. There results a spacer with an Inconel grid and surrounding Zircaloy band having minimum pressure drop and minimum neutron absorption useful with a high density fuel rod matrix required in modern fuel bundle design.
041636902	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a generally central portion of a fuel assembly spacer grid 20 composed of a plurality of grid plates 21, 22, 23, 24, 25, 26 intersecting and interlocking, as described hereinafter, to form a multiplicity of cells 30 of substantially open cross section. A plurality of nuclear fuel pins 31, disposed through the cells with their longitudinal axes 32 parallel, the laterally spaced and supported by the grid plates. The construction of the individual grid plates 21, 22, 23, 24, 25, 26 includes three distinct designs. The first design, representative of identical grid plates 21, 22, is best shown in FIGS. 2 and 3. The grid plate 21, 22 of which only 21 is described in detail for illustrative purposes, is a substantially flat rectangular sheet of material which has mutually opposing faces 33, 34, lengthwise edges 35, 36 and widthwise edges 37, 38 (only widthwise edge 38 being shown in FIG. 2). The lengthwise edges 35, 36 are orientated transversely with respect to the longitudinal axes of the fuel pins and the widthwise edges 37, 38 are oriented in parallel with the longitudinal axes of the fuel pins. The edges 35, 36 span the breadth of the fuel assembly spacer grid. A ridge 41 (FIG. 2) is located in the edge 35 of each grid plate 21. A transverse slot 51, extending a distance 60, is cut out of the grid plate 21 through the center of ridge 41. The slot 51 is chamfered at edge 35. Like-dimensioned ridges 42 are formed at equidistantly spaced intervals along the edge 35 on either side of ridge 41. A plurality of paddle shaped slots 52, each transversely intersecting a ridge 42 through edge 35, is cut out of the grid plate 21. Each paddle shaped slot 52 includes a narrow slot 53, chamfered at the edge 35, which extends a distance 61 to a broader generally rectangular cutout 54. The rectangular shaped cutout extends an additional distance 62 away from edge 35 and is centrally disposed in longitudinal axial alignment with slot 53. A ridge 43 is formed in edge 36 longitudinally opposite ridge 41 in edge 35. A transverse slot 55, chamfered at edge 36, intersects ridge 43 and extends a distance 60 from edge 36. A plurality of like-dimensioned ridges 44 are equidistantly spaced at intervals along edge 36 on either side of the ridge 43. The ridges 44 of edge 36 are disposed longitudinally opposite ridges 42 of edge 35. A single rectangular cutout 56, having dimensions corresponding to those of rectangular cutout 54, is disposed in the center of the plate 21. Cutout 56 is equidistantly spaced between and longitudinally aligned with slots 51 and 55, and laterally aligned with cutouts 54. A plurality of panels 57 is defined by the areas between adjacent cutouts, 54, 56. The plate 21 is also provided with a plurality of protrusions 71, 72 raised from face 33 and protrusions 73 raised from face 34 at spaced intervals through its length and breadth. Protrusions 71 and 72 project from the portion of the face 33 generally between the ridges of the edges 35 and 36, respectively, in one direction; protrusions 73 project the center portion of the face 34, spaced longitudinally between the edges 35, 36 and laterally between the rectangular cutouts, in the opposite direction. Each protrusion of plate 21, is longitudinally aligned with the protrusions having unlike reference numerals and laterally aligned with the protrusions having like reference numerals. A peak 74, having a minimal surface area, is formed at the apex of the protrusion 73. Each raised face or surface of the protrusion 73 leading to the apex 74 is provided with an aperture 75. The protrusions 71, 72 have a configuration that is identical to the one described in connection with the protrusion 73. A second grid plate design, representative of the identical grid plates 24, 25, is shown in FIGS. 4 and 5. The grid plates 24, 25 of which only 24 is described in detail for illustrative purposes, is a generally flat rectangular sheet of material which has mutually opposing faces 81, 82, lengthwise edges 83, 84 and widthwise edges of which only the widthwise edge 89 is shown in the drawing. The lengthwise edges 83, 84 are orientated transversely with respect to the longitudinal axes 32 of the fuel pins 31, and the widthwise edge 89, save for small sloping portions, is orientated in parallel with the longitudinal axes 32 of the fuel pins. Edge 83 is interrupted at equally spaced intervals by a plurality of like-dimensioned paddle shaped slots 85. Each paddle shaped slot 85 includes a broader generally rectangular slot 86 extending transversely from edge 83 a distance 65 and connecting with a narrower slot 87. The narrower slot 87 extends a distance 64 further into the plate 24 and is in longitudinal alignment with slot 86. Like-dimensioned ridges 45 are disposed at equally spaced intervals, along edge 84 generally aligned opposite the paddle shaped slots 85. Portions of the grid plate 24 located between the paddle shaped slots 85 define a plurality of similar panels 88, only one of which is shown, cantilevered away from edge 84. A substantial portion of each cantilevered panel 88 that is spaced between slots 86 is bowed transversely out of alignment with the planes of the faces 81, 82 over a distance 62 terminating in a planar lip at edge 83, the lip being in the same plane as that established by the faces 81, 82. The bow projects in a direction such that the arc in face 81 is defined by a radius of curvature larger than that of the bowed portion face 82. A protrusion 90 is raised from the face 81 on each panel 88 peaking at a minimal surface 91 at the apex of the protrusion. An aperture 92 is formed in two of the surfaces leading to the peak 91 of protrusion 90. The third grid plate design, representative of the identical grid plates 23, 26, is shown in FIGS. 6 and 7. The grid plates 23 or 26 of which only 23 is described in detail for illustrative purposes, is a generally flat rectangular sheet of material which has mutually opposing faces 93, 94, lengthwise edges 95, 96 and widthwise edges (only the edge 97 being shown in FIG. 6). The widthwise edge 97 is identical to widthwise edge 89 of plate 24. The lengthwise edges 95, 96 are orientated transversely with respect to the longitudinal axes of the fuel pins, and the widthwise edge 97 is orientated in parallel with the longitudinal axes 32 of the fuel pins, save for a small sloping portion at the corner between edges 96 and 97. A rectangular slot 101 transversely intersects the edge 95 for a depth 65. Like-dimensioned paddle shaped slots 102 are formed at equidistantly spaced intervals along the edge 95 on either side of slot 101. Each paddle shaped slot 102 includes a broader generally rectangular slot 103 extending from edge 95 connecting with a narrower slot 104. The dimensions of slot 103 correspond to that of slot 101. The narrower slot 104 extends into the plate 23 a further distance 64. A ridge 46 is located in edge 96 of grid plate 23. A transverse slot 105, extending a distance 60 into the plate 23, is cut through the center of ridge 46. The slot 105 is chamfered at edge 96. A plurality of like-dimensioned ridges 47 is formed at equidistantly spaced intervals along edge 96 on either side of ridge 46, and generally in longitudinal alignment with paddle shaped slots 102. The portions of the grid plate 23 located between slot 101 and adjacent slots 103 define two cantilevered panels 106. The portions of the grid plate located between adjacent slots 103 define a plurality of panels 107, only one of which is shown (FIG. 6). Panels 106 are cantilevered away from edge 96 and are bowed transversely out of alignment with the plane of the faces 93, 94 for a distance 62 terminating in a planar lip that is in longitudinal alignment with the planar faces 93, 94 leading to edge 95. The bow projects in a direction such that the arc in face 93 is defined by a radius of curvature larger than that of the bowed portion of the opposing face 94. Panels 107 also are cantilevered away from edge 96. Panels 107 are bowed out of alignment with the plane of the faces 93, 94 over a distance 62 commencing at the inner recess of slot 103, over a distance 62, and terminating in a planar lip that is in longitudinal alignment with the planar faces 93, 94 leading to edge 95. A protrusion 108 is raised from the face 93 of each panel 106, 107 to a peak 109 at the apex of the protrusion. An aperture 98 is formed in two of the surfaces leading to the peak 109. FIG. 8 illustrates a portion of a corner section of spacer grid 20 including a peripheral band 110 which encircles the grid structure in communication with the widthwise edges of the associated grid plates. As can be seen in FIGS. 9 and 10, the peripheral band 110 is a generally flat sheet of material having a mutually opposing inner face 111 and outer face 112, and lengthwise edges 113, 114. A plurality of like-dimensioned rectangular cutouts 115, having their longer edges oriented in parallel with the longitudinal axes 32 of the fuel pins, are centrally disposed between the edges 113, 114 at equidistantly spaced lateral intervals. The peripheral band has a plurality of protrusions 116, 119 raised from the inner face 111 which project into the peripheral cells. A peak 117, having a minimal surface area, is formed at the apex of the protrusion 116. Apertures 118 (FIGS. 8, 10) are formed in each of the raised surfaces of protrusions 116 leading to peak 117 (FIG. 10). As shown in FIG. 9, the band 110 is not as wide as the maximum width of the plates 21, 22. The sloping portion of the widthwise edge 37 thus forms a transition section that matches the greater width of the grid plate 21 to the lesser width of the band 110. The widthwise edges of the remaining plates are similarly sloped (not shown), as described hereinbefore, to form a transition to the narrower peripheral band. The band 110 forms right angle corners 120 which are bevelled, as shown in FIG. 9, to provide a generally vee shaped cut in the lengthwise edges 113, 114. The protrusions 119 which laterally border each corner are spaced longitudinally closer to each other than the protrusions 116 which do not border the corners of the peripheral band. The protrusions 119 have a configuration that is similar to the one described above in connection with protrusion 116. In a preferred embodiment of the invention, a spring like bowed member 121 (FIG. 10) protrudes from face 112 of the band 110. A fuel element spacer grid plate lattice is arranged, in accordance with a preferred embodiment of the invention and, as is best shown in FIGS. 1 and 11, with a first pair of grid plates 23, 25 (FIG. 11) disposed in longitudinally opposite and inverted relation with each other. A second pair of dissimilar grid plates 24, 26, are similarly arranged in a spaced longitudinal orientation. The lips between the end of the arcuate cantilever and the edges 83, 95 generally overlap a portion of a face of the longitudinally opposite grid plate. As is shown in FIG. 11, grid plate 23 is arranged to perpendicularly intersect and interlock with plate 24 by aligning a paddle shaped cutout 85 (FIG. 4) of plate 24 superjacent to the slot 105 (FIG. 6) of grid plate 23, and by meshing these slots 85, 105 until (as is shown in FIG. 11) the plates interlock so that edge 84 at ridge 45 of plate 24 attains a flush crisscross alignment with the ridge 46 of plate 23 due to the fact that the distance 60 of the slot 105 of plate 23 coincides with the distance between the ridge 45 and slot 87 of plate 24. It has been noted, hereinbefore, that plate 26 is identical to plate 23, and that plate 25 is identical to plate 24. In order to follow the description of the cooperation of the plates 24 and 25 with each other and the remaining plates, it should be understood that the detailed reference numerals of plates 23 and 24 are applicable to plates 26 and 25, respectively. It can be seen that the distance 60 of the cut of slot 105 of plate 26 (FIG. 6) coincides with the distance 60 between the edge 84 at ridge 45 of plate 25 (FIG. 4) and the closest portion of the longitudinally aligned slot 87 of plate 25. Therefore, grid plate 26 is arranged to intersect and interlock with grid plate 25 by aligning slot 105 (FIG. 6) perpendicularly superjacent to a paddle shaped cutout 85 (FIG. 4) of plate 25, and by engaging the slot 105 and cutout 85 until (as is shown in FIG. 11) the plates interlock with ridges 46 of plate 25 in flush crisscross alignment with ridge 45 of plate 26. Although dissimilar plates are paired in the described embodiment, it should be noted that this is not essential to the practice of the invention. Thus, the plates 23, 26 could be paired together to intersect and interlock with a paired plate 24, 25. It can be seen (FIGS. 1, 11) that the paired plates are arranged in perpendicular longitudinal planes, within the lattice, to intersect along a single longitudinal line in the spacer grid. Plates 21 are grouped in parallel arrangement with the paired plates 23, 25 (FIG. 1). Moreover, the plates 21 are disposed on either side of the paired plates with faces 33 of plates 21 turned in the direction of the paired plates 23, 25. Plates 22 are orientated in parallel with paired plates 24, 26. Plates 22 are inverted and in perpendicular relationship with plates 21. The plates 22 are grouped in parallel arrangement on either side of the paired plates so that the faces 33 of plates 22 are directed toward the paired plates 24, 26. Plates 21 and 22 are assembled in a perpendicularly interlocking and intersecting relation by orienting them at superjacent right angles such that the inverted paddle shaped slots 52 are aligned, and by drawing them together. Upon interlocking the plates 21, 22, it can be seen (FIG. 9) that edge of the ridge 42 of one plate is flush with the edge of the ridge 44 of the other. Plate 24 perpendicularly intersects each of the plates 21 at their respective individual slots 55 (FIG. 2), by superjacently aligning slots 85 (FIG. 4) of the plates 24 with slots 55 of the plates 21 and drawing them together until the plates interlock. Upon interlocking, ridges 45 of plate 24 will be in flush crisscrossed alignment with ridges 43 of plates 21. The plate 26, an illustrative embodiment of which is shown by the plate 23 in FIG. 6, which is longitudinally paired with plate 24, will similarly be drawn together with plates 21 so that ridges 47 of plate 26 will be crisscrossed and flush with ridges 42 of plates 21. Plate 23 (FIG. 6) perpendicularly intersects plates 22, an illustrative embodiment of which is shown by the plate 21 in FIG. 2, at slot 51 by superjacently aligning slots 102 of the plates 23 with slots 51 of the plates 22 and drawing these together until the plates interlock. Upon interlocking, ridges 47 (FIG. 6) of plate 23 will be crisscrossed and flush with ridges 41 of plates 22 (FIG. 2). Paired plate 25, an illustrative embodiment of which is shown by the plate 24 is FIG. 4, is similarly interlocked with the opposing edge 36 of each plate 22 by superjacently aligning paddle shaped slots 85 (FIG. 4) of the plates 25 with slots 55 (FIG. 2) of the plate 22 and drawing them together until they interlock, with ridges 45 of plate 25 crisscrossed and flush with ridges 43 of plates 22. The grid plates are made from somewhat resilient material compatible with nuclear reactor operating conditions and preferably having a low neutron absorption cross section. The fuel pins are made of a nuclear fuel material encapsulated in a thin-walled, slender, elongated sheath of a metal cladding material which has a coefficient of expansion that is substantially the same as that of the material of which the grid plates are constructed to essentially eliminate differential thermal expansion between the grid plates. Chamfering of the slots at the edges of the various plates facilitates the interlocking, described hereinafter, of the plates. The widthwise edges of the grid plates 21, 22, 23, 24, 25, 26 are held in rigid communication with the face 111 of the band 110 by welding, brazing (not shown) or other well known means. The crisscrossed ridges, described hereinbefore, serve as surfaces for the deposition of material to rigidly join the perpendicularly interlocked plates into position by welding, brazing or other means. The apertures in the protrusions allow reactor coolant (not shown) to flow about the protrusions with minimum hydraulic pressure loss and flow stagnation. The panels 57 (FIG. 2) formed between the cutouts 54, 56 of the plates 21, 22 can be mechanically flexed within the elastic range of the plate material by external means. The cantilevered panels 88, 106, 107 (FIGS. 6, 11) of grid plates 23, 24, 25, 26 may also be flexed by external means as described hereinafter. The adjacent cutouts, in conjunction with the rigid ridge communication described above, cause the panels 57, 88, 106, 107 to be relatively more flexible than the remainder of the plates. Protrusions 73 on plates 21, 22 are on panels 57 (FIG. 2). As stated, panels 57 may be fixed, within the elastic range of the plate material, from their equilibrium plane by external means but have sufficient resilience to return to that plane after the deflecting means are removed. Protrusions 71 and 72, are located near edges 36 and 35 respectively. Since the ridges of intersecting plates are rigidly joined together, the portions of the plates upon which these protrusions 71, 72 are located is relatively inflexible. Hence, protrusions 73 may be characterized as resilient, since these are movable with panel 57, and protrusions 71, 72 may be characterized as rigid since these are relatively fixed in position. As shown in FIG. 11, the cantilevered panels 88, 106 arc from the base of their plates until their planar surfaces are in transverse contact with the base of the plate longitudinally opposed thereto. Each of the cantilevered panels may be flexed, within the elastic range of the plate material, through the application of an external force, and has sufficient resilience to return to its equilibrium position after the means for applying the external force are removed. Hence, the protrusions 90, 108 may be characterized as resilient due to the resilience of the members on which they are located. Protrusions 116, 119 on band 110 (FIG. 9) are characterized as rigid as the portions of the band upon which these are located are relatively inflexible. Arrangement of the paired plates 23, 25, and individual paired plates 24, 26, with the plates in each pair in longitudinally spaced alignment and inverted with respect to each other, results in the projection (FIGS. 1, 12) of a resilient protrusion 90, 108 into each cell bordering the plates 23, 24, 25, 26. As stated, plates 21 are orientated in parallel with paired plates 23, 25, (FIG. 1). The plates 21 on either side of the paired plates are disposed with face 33 directed toward the paired plates with which the plates 21 are in parallel. The faces 33 of plates 21 on one side of and directed toward the paired plates 23, 25 mirror faces 33 of plates 21 disposed on the opposite side of the paired plates. Hence, the rigid protrusion 71, 72 of each plate 21 projects toward paired plates 23, 25. Similarly, plates 22 are orientated in parallel with paired plates 24, 26 so that the rigid protrusions 71, 72 of each plate 22, on either side of paired plates 24, 26, projects toward the paired plates 24, 26. The faces 33 of plates 22 on one side of and directed toward the paired plates 24, 26 mirror the faces 33 of the plates 22 disposed on the opposite side of the paired plates. Hence, as is best seen in FIGS. 1 and 12, each cell 30 is bordered by two adjacent surfaces having only resilient protrusions opposed by two adjacent surfaces having only rigid protrusions. The use of the paired plates 23, 25 and paired plates 24, 26, in the manner set forth above, allows reversal of the faces of the remaining plates on either side of the paired plates so that while maintaining mutually adjacent resilient protrusions opposite adjacent rigid protrusions projecting from the borders of each cell, only rigid protrusions are employed in the peripheral band 110. The resulting peripheral band has greater strength and is capable of withstanding higher impact loads. Furthermore, a spring like member 121 (FIG. 10) may be formed on the outsdie face 112 of the peripheral band 110. Since the member 121 is generally located between cutouts 115, it may be flexed. Location of band 110 in lateral alignment and in contact with the peripheral bands of juxtaposed fuel assemblies in the reactor core will compress the member 121 causing each band to bear against the adjacent band in tension and resulting in positive lateral support. Moreover, the member 121 (FIG. 10) can similarly bear in tension against the inner walls of a fuel assembly can to rigidly hold the assembly in position in a reactor utilizing cans to encircle the fuel assembly. The fuel pins, are typically supported laterally by a plurality of spacer grids at intervals along their length. Referring now to FIG. 12, deflecting means (not shown), such as described in U.S. Pat. No. 3,665,586 issued to F. S. Jabsen on May 30, 1972, may be utilized to deflect the panels resilient protrusions projecting into a cell, to allow a fuel pin to be freely inserted. After the fuel pin 31 is positioned within the cell, the deflecting means is actuated to release the resilient protrusions thereby allowing the panels containing the resilient protrusions to bear against the fuel pin in tension and laterally jam the pin against the opposing rigid protrusions to support the fuel pin and retain it in position within the cell. The deflecting means can be inserted into the open channels 122 (FIG. 11) typically formed by the cooperation of the rectangular openings 54, 56, 86, 101, 103 of the grid plates. The magnitude of the lateral forces imparted onto a fuel pin by the protrusions is designed to securely restrain the pin and to minimize fretting without overstressing the cladding at the points of contact. From the foregoing, it can be easily understood that the described spacer grid assembly achieves the desired results of providing a grid lattice usable in either a "canless" or "can" type reactor core, having cells which utilize a combination of resilient and rigid protrusions in contact with the fuel pins, resulting in a substantially stronger outer band, and minimizing the amount of material capable of causing undesirable hydraulic pressure losses, parasitic absorption of neutrons and fuel pin hot spots at grid plate to pin contact points. Except where qualified, the term "generally central", in the specification and the claims, includes a slight offset of the intersections of the paired plates from the center of the grid plate lattice so that an odd numbered array of cells could be formed, e.g., a 17.times.17 array, in addition to arrangements which would give even numbered arrays of cells.
042382882	description	DETAILED DESCRIPTION OF THE INVENTION According to the invention, the drive of a nuclear reactor's control element comprises an electromotor 1 (FIG. 1) having a housing 2 which accommodates a stator 3 and a composite rotor 4. The stator 3 is insulated from the reactor's coolant by a shield 5. Lengthwise, the rotor 4 is composed of two parts whose total length is equal to the length of the active part of the stator 3. One part of the rotor 4 is a solid cylinder-shaped member 6, whereas the other comprises three double-arm rocking levers 7 (FIG. 2). Mounted on the outer surface of the solid cylindrical member 6 (FIG. 1) of the rotor 4 are rods 8, each having one of its ends secured in a ring 9, whereas their other ends are secured in a ring 10 mounted on a spindle 11 rotatable in bearings 12 and 13. The bearings 12 and 13 are arranged in housings 14 and 15, respectively, which, in turn, are accommodated in the housing 2 of the electromotor 1. Arranged inside the spindle 11 are centering bushings 16 through which there extends a drive screw 17 coupled to a control element (not shown). The rods 8 and rings 9 and 10 make up a grid for starting the electromotor 1. Pivot axles 18 (FIG. 3) of the double-arm levers 7 are parallel to the axis of the drive screw 17. One end of each of the pivot axles 18 is secured in the ring 10 (FIG. 1), whereas the opposite end is secured in a lug 19 (FIG. 3) provided in the spindle 11. First arms 20 of the double-arm rocking levers 7 act as poles of the rotor 4 (FIG. 1). Second arms 21 (FIG. 3) of the levers 7 are forked and carry rollers 22 whose rotation axles 23 are secured in the forks so that they are parallel to the axis of the drive screw 17. The rollers 22 (FIG. 2) form a detachable roller nut interacting with the drive screw 17 through apertures 24 provided in the spindle 11 due to the action of the electromagnetic field of the stator 3 (FIG. 1) upon the double-arm levers 7. Each arm 20 (FIG. 3) of the double-arm levers 7 has a lug 25 which accommodates a spring 26 (FIG. 4) intended to actuate a stop 27. The extent of displacement of the arm 20 (FIG. 3) of the double-arm lever 7 is limited by a stop 28 provided on the ring 10 (FIG. 1). The present invention has been described herein with reference to a preferred embodiment of a drive of a nuclear reactor's control element, wherein the rotor contains three double-arm rocking levers. It is apparent, however, that use can be made of a greater number of levers without altering the spirit of the invention. The operating principle of the proposed drive of a nuclear reactor's control element is as follows. As supply voltage is fed to the stator 3 (FIG. 1) of the electromotor 1, the resultant electromagnetic field interacts with the solid cylinder-shaped member 6 and rotates the composite rotor 4. At the same time the electromagnetic field of the stator 3 interacts with the arms 20 (FIG. 2) of the double-arm rocking levers 7 and pivots them in the radial direction about the axles 18; as a result, the rollers 22 of the detachable roller nut engage with the drive screw 17 which drives the control element. As the stator 3 (FIG. 1) of the electromotor 1 is deenergized, the double-arm rocking levers 7 (FIG. 2) are pivoted in the opposite direction by the stop 27 (FIG. 4) and the spring 26, whereby the rollers 22 (FIG. 2) are disengaged from the drive screw 17, and the control element is dropped under gravity by an emergency protection signal. By altering the sequence of connection of the supply voltage phases, one can change the direction of rotation of the rotor 4 (FIG. 1) and, consequently, the direction of motion of the drive screw 177 and the control element. Whenever it is necessary to stop the control element and keep it at any desired level, d.c. voltage is applied to the stator of the electromotor. The proposed drive of a nuclear reactor's control element is of a small size and simple to control; at the same time it guarantees a stable and failsafe operation of the reactor's control and protection system. While preferred forms and arrangements have been shown in illustrating the invention, it is to be clearly understood that various changes in detail and arrangement may be made without departing from the spirit and scope of this disclosure.
	abstract	A long-term storage container (1) for storage of radioactive material to inhibit radioactive radiation therefrom to the outside of the container, the top of said container to be closed by a screw-on radioactive radiation inhibiting lid (7), said container having an integral inner container part (2; 34; 62; 62′) of a first material, e.g. plastic material, an integral outer container part (3; 43; 69) of a second material, e.g. plastic material, and radioactive radiation inhibiting material (4; 38; 68) in an inter-space between the walls and bottoms of said inner and outer container parts. To fill the inter-space an inter-space container part (4; 38; 68) is integrally moulded through injection or pressure moulding and then fitted onto the inner container part (2; 34; 62; 62′) to subsequently mould the outer container part (3; 43; 69) onto the outside of the inter-space container part (4; 38; 68). A specially made container lid (7) is provided. A preferred twin-mould moulding apparatus (61) provides for simultaneous pre-casting of the inner container part (62′) and the outer container part (69) in a respective mould of the apparatus.
	description	This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of Korean Patent Application No. 10-2015-0011189, filed on Jan. 23, 2015, the entire contents of which are hereby incorporated by reference. This invention has been published in Journal of the Korean Society of Tribologists & Lubrication Engineers on December 2014. 1. Field of the Invention The present invention relates to a water-soluble coating composition applied on the surface of nuclear fuel rods to prevent scratching of the surface of the fuel rods, which are disposed in a nuclear fuel assembly for light water reactors. More particularly, the present invention relates to a water-soluble coating composition, which facilitates the formation and removal of a coating film and in which the resulting coating film may exhibit strength and durability equivalent to those of an existing lacquer coating film. 2. Description of the Related Art In order to manufacture nuclear fuel assemblies for light water reactors, fuel rods are loaded into a skeleton. As such, the surface of the fuel rods is coated with lacquer to prevent or minimize scratching of the surface of the fuel rods and to enable efficient loading of the fuel rods. Currently, lacquer that is useful for coating nuclear fuel rods is nitrocellulose (NC) lacquer. This lacquer is a paint material that forms a protective coating film when the solvent evaporates therefrom, and enables the formation of a tough and rigid film despite having a quick drying rate. The coating film thus formed is dissolved again in a solvent for a de-lacquering process. The solvent used for the de-lacquering process is butyl acetate. Nitrocellulose (NC), currently used as the lacquer material, is a derivative of a natural polymer, cellulose, and is in a white powder phase, but is difficult to handle because it has explosive combustion properties to the extent that it serves as the main component of gunpowder. Furthermore, nitrocellulose may be formed into a rigid film by the evaporation of a solvent, but such a film may become brittle. Hence, the addition of a plasticizer and an alkyd resin is required to form a coating film having proper hardness and flexibility. Moreover, such a film is used under the condition that it is dissolved in an organic solvent to ensure appropriate liquidity, which undesirably and inevitably causes environmental pollution problems due to the use of the organic solvent. Hence, the need for the development of safe and harmless alternatives to lacquer has arisen, but organic solvent type lacquer is still used to date, owing to the absence of suitable alternatives. In particular, a lacquering process for preventing scratching of the surface of nuclear fuel rods and a de-lacquering process for removing the lacquer coating after the fuel rods have been loaded, or processes similar thereto, cannot be found even in foreign companies such as Westinghouse or AREVA. Furthermore, techniques and inventive results for water-soluble coating compositions, including loading of fuel rods without a coating film or via spraying of water, are still lacking. Coating processes using organic solvents are general, and thus domestically ensured, but have a recent tendency to be replaced by safe water-based coating systems. Thorough research into water-soluble materials is ongoing, and overcoming the limitations of water is regarded as a critical factor influencing the success of the invention. Therefore, the present inventors have studied water-soluble coating materials based on the use of a water solvent, as an alternative to lacquer, in order to improve the working environment of field workers for nuclear fuel rod coating and to remove workplace risks such as fire or explosion hazards, and have ascertained that properly chosen water-soluble polymer resin candidates may be dissolved in water and mixed with a water-soluble volatile material such as alcohol, ultimately developing a water-soluble polymer composition applicable to a water-based system by forming a coating film at an appropriate thickness with a suitable rate of evaporation, which has led to the present invention. Accordingly, an object of the present invention is to provide a water-soluble coating composition for coating the surface of a nuclear fuel rod, which facilitates the formation and removal of a coating film on and from the surface of the nuclear fuel rod and in which the resulting coating film may exhibit strength and durability equivalent to those of an existing lacquer coating film. In order to accomplish the above object, the present invention provides a water-soluble coating composition for protecting the surface of a nuclear fuel rod, comprising a polymer resin of methacrylic acid and 2-hydroxyethyl methacrylate. The water-soluble coating composition may further comprise a methyl methacrylate polymer resin. The water-soluble coating composition may further comprise a polymer resin of styrene or 2-acrylamido-2-methyl propane sulfonic acid. The water-soluble coating composition may be a polymer resin comprising 52-62 wt % of methacrylic acid, 34-42 wt % of 2-hydroxyethyl methacrylate, and 0.01-12 wt % of methyl methacrylate. In addition, the present invention provides a coating solution for protecting a nuclear fuel rod, obtained by dissolving a polymer resin comprising 52-62 wt % of methacrylic acid, 34-42 wt % of 2-hydroxyethyl methacrylate and 0.01-12 wt % of methyl methacrylate in a solvent mixture of isopropanol, ethanol and water. The coating solution may comprise 9-12 wt % of the polymer resin and 88-91 wt % of the solvent mixture of isopropanol, ethanol and water. In addition, the present invention provides a coating method for protecting the surface of a nuclear fuel rod, comprising: (1) forming a coating film on the surface of a nuclear fuel rod, using a coating solution obtained by dissolving a polymer resin comprising 52-62 wt % of methacrylic acid, 34-42 wt % of 2-hydroxyethyl methacrylate and 0.01-12 wt % of methyl methacrylate in a solvent mixture of isopropanol, ethanol and water; (2) drying the nuclear fuel rod; and (3) loading the dried nuclear fuel rod in a skeleton. As such, forming the coating film in (1) may be performed while a concentration of the coating solution is corrected to be maintained at an initial value by measuring a density of the coating solution using a hydrometer. Furthermore, drying the nuclear fuel rod in (2) may be performed using hot air drying or air drying. According to the present invention, a water-soluble coating composition facilitates the formation and removal of a coating film and in which the resulting coating film can manifest strength and durability equivalent to those of an existing lacquer coating film. Hence, this coating composition is an effective replacement for existing lacquer. Furthermore, according to the present invention, the water-soluble coating composition for protecting the surface of a nuclear fuel rod is water soluble, and thus the coating film can be easily removed by washing with water, ultimately improving workplace safety to thus achieve improvements in the working environment and high workplace safety, compared to conventional methods using lacquer. Hereinafter, a detailed description will be given of the present invention. An aspect of the present invention addresses a water-soluble coating composition for protecting the surface of a nuclear fuel rod, comprising a polymer resin of methacrylic acid and 2-hydroxyethyl methacrylate. The composition may further include a methyl methacrylate polymer resin. The composition may further include a polymer resin of styrene or 2-acrylamido-2-methyl propane sulfonic acid. The composition is preferably a polymer resin comprising 52-62 wt % of methacrylic acid, 34-42 wt % of 2-hydroxyethyl methacrylate, and 0.01-12 wt % of methyl methacrylate. Particularly useful is a polymer resin comprising 52-56 wt % of methacrylic acid, 34-38 wt % of 2-hydroxyethyl methacrylate, and 8-12 wt % of methyl methacrylate. Based on the experimental results, the use of a polymer resin comprising 54 wt % of methacrylic acid, 36 wt % of 2-hydroxyethyl methacrylate, and 10 wt % of methyl methacrylate is very effective at forming a coating film having the optimal properties. The present invention addresses a coating solution for protecting the surface of a nuclear fuel rod, obtained by dissolving the composition in solid form in a solvent mixture of isopropanol, ethanol and water. The coating solution preferably comprises 9-12 wt % of a polymer resin, and 88-91 wt % of a solvent mixture of isopropanol, ethanol and water. Based on the experimental results, the use of a coating solution comprising 9 wt % of a polymer resin and 91 wt % of a solvent mixture of isopropanol, ethanol and water is very effective at forming a coating film having the optimal properties. Another aspect of the present invention addresses a coating method for protecting the surface of a nuclear fuel rod, comprising: (1) forming a coating film on the surface of a nuclear fuel rod, using a coating solution obtained by dissolving a polymer resin comprising 52-62 wt % of methacrylic acid, 34-42 wt % of 2-hydroxyethyl methacrylate and 0.01-12 wt % of methyl methacrylate in a solvent mixture of isopropanol, ethanol and water; (2) drying the nuclear fuel rod; and (3) loading the dried nuclear fuel rod into a skeleton. In (1), the coating film may be formed while the concentration of the coating solution is corrected to be maintained at an initial value by measuring the density of the coating solution using a hydrometer. In (2), the drying may be performed using hot air drying or air drying. A better understanding of the present invention may be obtained via the following examples which are set forth to illustrate, but are not to be construed as limiting the present invention, as will be apparent to those skilled in the art. Below is a description of a method of preparing a water-soluble coating composition for coating the surface of a nuclear fuel rod. A coating composition was prepared by dissolving 9.0 wt % of a polymer resin comprising methacrylic acid (MAA), 2-hydroxyethyl methacrylate (2-HEMA) and methyl methacrylate (MMA) at a weight ratio of 5.4:2.7:0.9 in a solvent mixture comprising 28.0 wt % of isopropanol (IPA), 50.0 wt % of ethanol (EtOH), and 13.1 wt % of water. This coating composition is referred to as a YS-3 coating composition. Other coating compositions similar to the YS-3 coating composition were prepared and tested. The polymer resins and the solvents of individual coating compositions are given in Table 1 below. TABLE 1Polymer resin and solvent of water-soluble coating compositionAYS-1YS-2YS-3YS-4MAA3.66.05.65.45.42-HEMA5.43.22.82.72.7Other resin——0.9 (St)0.9 (MMA)0.9 (AMPS)Polymer9%9.20%9.30%9%9%resinIPA6.327.724.028.027.8EtOH50.050.050.050.050.0Water34.713.116.713.113.1Total100100100100100 As is apparent from Table 1, Resin A composed of MAA/2-HEMA is referred to by the new code name YS-1, and this composition was added with St (styrene) resin, MMA (methyl methacrylate) resin, and 2-acrylamido-2-methyl propane sulfonic acid (AMPS), thus synthesizing four new kinds of resins. A coating film was formed using the water-soluble coating composition on a flat plate sample made of the same material as in fuel rods, dried, and then measured for pencil hardness using a pencil hardness tester. The thickness of the coating film was measured using a light-reflecting coating thickness meter. Specifically, the coating film was placed under a light source and irradiated with near infrared light, after which the amount of reflected light was measured to determine the thickness in μm using the coating thickness meter. The adhesive strength was measured in a manner in which a 10×10 cm sized flat plate was coated with each kind of coating composition, the coating film was cut into coating pieces with a blade, and the number of detached coating pieces was counted when an adhesive tape that had been attached to the coating film was peeled from the coating film. The properties of the coating film were measured as above. The results are illustrated in the photograph of FIG. 1. As illustrated in FIG. 1, for washing feasibility, all of the coating films of YS-1 to YS-4 could be cleanly washed by water. The pencil hardness decreased in the sequence of YS-3→YS-1→YS-2=YS-4. The hardness of YS-3 was excellent. For adhesion measurement using an adhesive tape, all of the coating films exhibited superior adhesion, without peeling of the coating film by the adhesive tape. For coatability, which evaluates the extent of formation of a uniform coating film after drying, YS-3, YS-2, and YS-1 were slightly peeled, but the coatability thereof was determined to be good when the drying rate was controlled. The thickness of the coating films was measured to be 1.62-1.92 μm. In order to apply a water-soluble coating composition to actual fuel rods, a small fuel rod loading test apparatus was manufactured, and the load upon loading of fuel rods and the depth and width of scratches created on fuel rods were measured. The results of the water-soluble coating composition and the existing lacquer (NC) coating composition were compared and evaluated. The fuel rod loading test apparatus was manufactured by downscaling a skeleton having a size of about 4 m, which is the size actually used when loading fuel rods, to a size of 1.5 m, and was configured to include three spacer grids and a total of 289 grid cells in a 17×17 arrangement, into which 264 fuel rods could be loaded, aside from 24 guide thimble tubes and one instrumentation tube. The load applied to the loaded fuel rods varied depending on the loading position, which is depicted in FIG. 2 and is shown in Table 2 below. TABLE 2Classification of load for fuel rodNoClassification of loadMagnitude of load1Outermost corner cellsLow load2Cells in contact with outside spacer gridLow load3Cells close to center guide tubeHigh load4Cells around center guide tubeLow load5Cells close to outer guide tubeHigh load6Cells around outer guide tubeLow load7Outer cellsLow load As is apparent from Table 2, the sequence of load was assumed to be sample number 5=3>6>4>1>2>7. Based on these results, a fuel rod loading test was performed. To this end, Resin A, as a basis material, and YS-3, having the highest pencil hardness, were used. The loading positions are shown in red in FIG. 3. The high load position and the low load position were chosen so as to be symmetrical with each other. The existing lacquer (NC) coating composition and the water-soluble coating compositions made of Resin A (represented by MH200A) and YS-3 were compared and evaluated. As for the lacquer (NC) coating composition, the loading test was performed at high load positions of C4 and E4, one side of each of which was in contact with the guide tube, and at low load positions of A1 and B2, outer walls of which were in contact. For the YS-3 coating composition, the loading test was carried out at high load positions of C14 and E14 and at low load positions of A17 and B16. As for Resin A (represented by MH200A), the loading test was implemented at high load positions of M4 and O4 and at low load positions of Q1 and P2, so as to be symmetrical with the lacquer (NC) loading positions. Also, a non-coated virgin fuel rod was loaded at position P2. The load detected by the load cell fitted to the fuel rod loading test apparatus was measured in kg. The magnitude of the load depending on the loading time is graphed in FIGS. 4A to 5B. Based on the results of the magnitude of the load depending on the kind of coating composition in the loading test at low load positions as illustrated in FIGS. 4A and 4B, YS-3 exhibited slightly low or equal load, compared to lacquer (NC), and Resin A exhibited a high load, compared to two kinds of coating compositions. In particular, the non-coated virgin fuel rod had a greater load than the fuel rods treated with coating compositions. In the loading test at high load positions, Resin A showed the greatest load, and YS and lacquer (NC) were measured to have similar values. The scratching of the surface of the fuel rods in the loading test was analyzed, and thereby the effects of the coating film were compared. The depth and width of scratches were measured. The results are shown in Tables 3, 4 and 5 below. TABLE 3Results of measurement of scratching of fuel rods withexisting lacquer (NC) coating filmAverageUpper (4-side)Medium (4-side)Lower (4-side)Averagedamagedangle, °angle, °angle, °depthwidthSampleLoadPosition090180270090180270090180270μmmmNCLowA15.26.14.47.83.74.83.44.15.77.59.55.45.60.29loadB26.13.79.38.33.43.84.04.44.85.011.35.85.80.31HighC48.36.25.29.17.110.611.56.44.34.35.89.57.40.38loadE49.46.45.17.38.47.88.38.56.38.47.37.27.50.37Average7.35.66.08.15.76.86.85.95.36.38.57.06.60.34 TABLE 4Results of measurement of scratching of fuel rods with Resin A coating filmAverageUpper (4-side)Medium (4-side)Lower (4-side)Averagedamagedangle, °angle, °angle, °depthwidthSampleLoadPosition090180270090180270090180270μmmmALowQ18.58.47.45.47.07.29.27.39.88.18.36.77.80.30loadP27.36.08.611.27.16.810.67.88.09.58.49.28.40.38HighO48.96.75.76.211.27.05.15.88.45.78.29.47.40.29loadM49.19.49.88.86.77.45.36.37.36.810.28.88.00.34Average8.57.67.97.98.07.17.66.88.47.58.88.57.90.33 TABLE 5Results of measurement of scratching of fuel rods with YS-3 coating filmAverageUpper (4-side)Medium (4-side)Lower (4-side)Averagedamagedangle, °angle, °angle, °depthwidthSampleLoadPosition090180270090180270090180270μmmmYS-3LowA174.87.37.15.16.16.57.25.47.05.66.34.16.00.31loadB164.55.67.59.16.74.06.44.45.45.75.86.05.90.32HighC146.75.46.36.86.13.66.35.75.74.75.36.35.70.25loadE149.26.88.27.48.14.26.84.25.86.28.96.76.90.30Average6.36.37.37.16.84.66.74.96.05.66.65.86.10.30 For fuel rods coated with the existing lacquer (NC) coating composition, the fuel rods subjected to loading testing at low load positions were broadly divided into three portions, that is, the upper, medium and lower portions, and the depth of surface scratching was measured and averaged when individual portions of the fuel rods were rotated by 90°. At positions A1 and B2, the depth of scratching was measured to be 5.6 and 5.8 μm respectively, and at high load positions C4 and E4, the depth of scratching was measured to be 7.4 and 7.6 μm. Thus, scratches were more deeply formed in the loading test at high load positions than in the loading test at low load positions. For Resin A, the depth of scratching was measured to be 7.8 and 8.4 μm at low load positions and 7.4 and 8.0 μm at high load positions, and thus there was no significant difference therebetween, unlike lacquer (NC). Relatively deep scratching of an average of 7.9 μm was recorded. For YS-3 resin, the depth of scratching was measured to be 6.0 and 5.9 μm at low load positions and 5.7 and 6.9 μm at high load positions, and thus was regarded as low. In the fuel rod loading test apparatus, the coating films were formed using three kinds of coating compositions, after which the loading test was performed, and the depth of scratching of the fuel rods was measured at angles in four directions with respect to three portions. Compared to the existing lacquer (NC) coating composition, scratching occurred to a deeper extent when using the Resin A coating composition, and occurred to a lesser extent when using the YS-3 resin coating composition. Hence, the YS-3 coating composition of the invention was found to be suitable for use as a water-soluble coating composition. Five fuel rods were coated with a YS-3 coating solution, three of which were dried for one day using hot air drying, and two of which were dried for one day using air drying. Thereafter, a loading test was performed using a fuel rod loading test apparatus, and the load was measured. The results are illustrated in FIGS. 6A and 6B. As illustrated in FIGS. 6A and 6B, in air drying, the fuel rods (P1, Q1) had a high load of 20 kg/cm2 or more, but this was attributable to experimental error, and no significant difference was found. In hot air drying, the load was slightly decreased compared to air drying. Hence, hot air drying was determined to be more effective at forming the coating film, and was superior in scratch testing when evaluated with the naked eye. For field demonstration testing of the water-soluble coating composition (YS-3), which was ultimately selected as an alternative to lacquer, a coating tank for a water-soluble coating composition was separately manufactured. A washing process was performed using a cleaning tank that had been newly manufactured so as to have the same size as the coating tank. Lead pellets were loaded in the fuel rods, and dummy fuel was manufactured under the same conditions as in the commercial production of existing lacquer (NC), tested and evaluated. In a coating process, the water-soluble coating solution (YS-3) was fed to a coating level of the coating tank (feed amount: about 350 kg, feed time in coating tank: 15 min), and the fuel rod assembly was incorporated in the coating tank and maintained for 5 min. In a drying process, the coating solution was drained to the bottom of the coating tank (requiring 3 min) and compressed air was blown for 25 min. After blowing for 25 min, the state of dryness was checked. Then, the fuel rod assembly was taken off the coating tank and then subjected to air drying, which required a total of 1.5 hr. FIG. 7 illustrates the results of measurement of load and noise in field demonstration testing. Load and noise results very similar to those of fuel rods coated with existing lacquer (NC) were exhibited. As illustrated in FIG. 8, surface scratch testing of fuel rods was performed using four blue outermost cells at low load positions, four yellow general cells at low load positions, and four red cells around guide tubes at high load positions. As is apparent from Table 6 below, the damaged depth was an average of 12.5 μm, satisfying allowable standards of 25 μm or less, and the damaged width was an average of 0.6 mm, satisfying allowable standards of 4.06 mm or less. Also, the scratching at high load positions was relatively deep compared to the scratching at low load positions. TABLE 6Results of measurement of surface scratching of fuel rodsDamaged depth of fuel rod at positionLoad-(standard: <25 μm)DamagedingUpperMediumwidthposi-(4-side)(4-side)Lower (4-side)standardNo.tion00090180270<4.06 mm1A111.810.912.412.913.413.00.6562K111.711.612.111.312.213.10.5853G1713.012.812.712.110.613.40.6964Q112.211.612.012.213.612.90.5495F513.113.813.311.013.813.50.6146M613.613.113.512.813.713.40.6707H911.910.612.612.311.913.10.5478L1611.711.110.811.412.112.70.5639B312.110.912.313.213.112.90.60810P712.812.213.113.912.711.90.68611C1612.211.812.612.011.413.40.52912H1112.912.813.413.312.712.50.438Aver-12.411.912.612.412.613.00.595age To evaluate the effects of the water-soluble coating composition solution on the corrosion of fuel rods, high-temperature corrosion testing was performed at 150° C. As illustrated in FIG. 9, three fuel rod samples were prepared and placed in a glass vessel, after which a coating composition solution was charged in the glass vessel so that the samples were immersed therein. Then, the glass vessel was placed in a pressure-resistant bottle, and the pressure-resistant bottle was sealed, followed by digest testing in an electric oven at 150° C. for two weeks. Based on the corrosion test results, as illustrated in FIG. 10, the fuel rods did not corrode. The reason why the color of the surface thereof was pale brown is that the oxidized coating solution was not removed. The water-soluble coating composition includes the water-soluble polymer resin and the solvent comprising ethanol, isopropanol and water, and thus the flash point of volatile alcohol is regarded as important in terms of designing the process of coating fuel rods. Accordingly, the flash point of the water-soluble coating composition was measured. The results thereof depending on the measurement method are as follows. TABLE 7Results of measurement of flash pointFlash pointMeasurement method22° C.ASTM D56, Tag Closed Cup method23° C.ISO 3680, Rapid Equilibrium method The crude water-soluble coating solution has a low flash point of 22-23° C., and thus must be kept clear of fire and heat, and requires a ventilated device. Since the solvent having high volatility compared to the water-soluble polymer is volatilized in the water-soluble coating composition having the flash point measured as described above, there is a concern of causing variation in the thickness of the coating film with an increase in the concentration of the water-soluble polymer in the coating solution during usage. Hence, a measurement method that is able to maintain and correct the appropriate concentration of the coating solution is required. As illustrated in FIG. 11, a predetermined amount of coating solution was placed in a measuring cylinder, a hydrometer was immersed therein, and the density of the coating solution was measured. The initial density was measured to be 0.926 g/mL. Then, while the volume of the solution was reduced by the evaporation of alcohol, the density was measured. As shown in Table 8 below, the density was increased with a reduction in volume. Changes in density depending on the reduction in volume are depicted in FIG. 12, and the correlation therebetween is 0.9925 g/mL, which is evaluated to be nearly linear. Upon actual usage of the coating solution based on these results, the concentration of the coating solution may be corrected by measuring the density thereof. TABLE 8Changes in density with reduction in solvent of coating solutionVolume, mLReduction, %Density, g/mL40000.9263951.250.9273853.750.93038050.9323756.250.933 Although specific embodiments of the present invention have been disclosed in detail as described above, it is obvious to those skilled in the art that such a description is merely preferable exemplary embodiments and is not construed to limit the scope of the present invention. Therefore, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.
	summary
	claims	1. A measurement apparatus comprising: a first detector that measures an intensity of a sheet-shaped beam of synchrotron radiation, said first detector configured such that the intensity of the sheet-shaped beam of synchrotron radiation is integrated over the entire range of the beam in the thickness direction of the beam; a second detector for measuring the intensity of the beam at two points where positions along the thickness direction of the beam are different; and a calculator for calculating a beam profile in the thickness direction of the beam on the basis of the detections by said first and second detectors. 2. An apparatus according to claim 1 , wherein said second detector has two detection elements and has a mechanism for moving said detection elements in the thickness direction of the beam. claim 1 3. An apparatus according to claim 1 , wherein said first detector has a detector having a photo-receiving surface capable of receiving, at only one time, the beam over the entire range of the beam in the thickness direction of the beam. claim 1 4. An apparatus according to claim 1 , wherein said first detector measures a total intensity by detecting accumulated synchrotron current. claim 1 5. An apparatus according to claim 1 , wherein said first detector measures a total intensity with respect to a beam extracted from a beam line different from the beam line from which the beam whose intensity is measured at the two points is extracted. claim 1 6. An apparatus according to claim 1 , wherein the spacing between the two points is not more than 1.5 times the size of the beam in the thickness direction or not less than 2.5 times the size of the beam in the thickness direction. claim 1 7. An apparatus according to claim 1 , wherein said calculating means determines a correction function for calculating position or size of the beam in the thickness direction on the basis of a total intensity and the intensities at the two points, on the basis of the results of the measurements of the total intensity, which are performed in advance, and the measurements of the intensities at the two points, which are performed in advance while detection elements of said second detector are moved in the thickness direction of the beam. claim 1 8. An apparatus according to claim 7 , wherein the measurements of the total intensity and the intensities at the two points, which are performed in advance, are performed under a plurality of conditions in which synchrotron accumulated current values are different. claim 7 9. An apparatus according to claim 7 , wherein the correction function is a polynomial equation. claim 7 10. A measurement method comprising the steps of: measuring an intensity of a sheet-shaped beam of synchrotron radiation, the intensity being integrated over the entire range of the beam in the thickness direction of the beam; measuring the intensity of the beam at two points where positions along the thickness direction of the beam are different; and calculating a beam profile in the thickness direction of the beam on the basis of the respective measurements. 11. A method according to claim 10 , further comprising a step for moving the intensity measurement points at two points in the thickness direction of the beam. claim 10 12. A method according to claim 10 , wherein the step of measuring a total intensity is performed by a radiation detector having a photo-receiving surface capable of receiving, at only one time, the beam over the entire range of the beam in the thickness direction of the beam. claim 10 13. A method according to claim 10 , wherein the step of measuring the total intensity is performed by detecting accumulated synchrotron current. claim 10 14. A method according to claim 10 , wherein the step of measuring the total intensity is performed with respect to a beam extracted from a beam line different from the beam line from which the beam whose intensity is measured at the two points is extracted. claim 10 15. A method according to claim 10 , wherein the spacing between the two points is not less than 2.5 times the size of the beam in the thickness direction of the beam. claim 10 16. A method according to claim 10 , wherein in said calculating step, one of position and size of the beam in the thickness direction is calculated on the basis of the total intensity and the intensities at the two points by using a correction function determined on the basis of the results of the measurements of the total intensity, which are performed in advance, and the measurements of the intensities at the two points, which are performed in advance while the intensity measurement point is moved in the thickness direction. claim 10 17. A method according to claim 16 , wherein the measurements of the total intensity and the intensities at the two points, which are performed in advance, are performed under a plurality of conditions in which synchrotron accumulated current values are different. claim 16 18. A method according to claim 16 , wherein the correction function is a polynomial equation. claim 16 19. An X-ray exposure apparatus comprising: a mirror for reflecting an X-ray beam from a synchrotron radiation source; a stage which holds a substrate to be exposed to the X-ray beam; and a measuring device disposed in proximity to said mirror, for measuring intensity distribution of the X-ray beam irradiating the substrate, the measuring device comprising: a first detector that measures an intensity of a sheet-shaped beam of synchrotron radiation, said first detector configured such that the intensity of the sheet-shaped beam of synchrotron radiation is integrated over the entire range of the beam in the thickness direction of the beam; a second detector for measuring the intensity of the beam at two points where positions along the thickness direction of the beam are different; and calculating means for calculating a beam profile in the thickness direction of the beam on the basis of the detections by said first and second detectors. 20. An apparatus according to claim 19 , wherein said first and second detectors are disposed so as to detect the beam incident on said mirror. claim 19 21. An apparatus according to claim 19 , further comprising means for obtaining intensity distribution of the beam on the substrate using a function of S and "sgr", S being a detection output of said first detector, and "sgr" being a standard deviation when the intensity distribution is approximated by a Gaussian distribution. claim 19 22. An apparatus according to claim 19 , further comprising a correcting mechanism for correcting the exposure of the substrate so as to evenly expose the substrate. claim 19 23. An apparatus according to claim 22 , wherein said correcting mechanism comprises a movable shutter. claim 22 24. A semiconductor device manufacturing method comprising: generating an X-ray beam from a synchrotron radiation source; reflecting the X-ray beam by a mirror to irradiate a substrate with the X-ray beam; measuring in proximity to said mirror, intensity distribution of the X-ray beam irradiating the substrate, said measuring step comprising: measuring an intensity of a sheet-shaped beam of synchrotron radiation, the intensity being integrated over the entire range of the beam in the thickness direction of the beam; measuring the intensity of said beam at two points where positions along the thickness direction of the beam are different; and calculating a beam profile in the thickness direction of the beam on the basis of the respective measurements; and exposing the substrate to the X-ray beam so as to transfer patterns of a semiconductor device. 25. A method according to claim 24 , wherein said measuring steps comprise detecting the beam incident on said mirror. claim 24 26. A method according to claim 24 , further comprising obtaining intensity distribution of the beam on the substrate using a function of S and "sgr", S being an integrated detection intensity, and "sgr" being a standard deviation when the intensity distribution is approximated by a Gaussian distribution. claim 24 27. A method according to claim 24 , further comprising correcting the exposure of the substrate so as to evenly expose the substrate. claim 24
	abstract	Systems and methods for long term disposal of high level nuclear waste in deep geologic formations are described. Such systems and method may include largely intact spent nuclear fuel rods in a disassembled form that may be placed into waste-capsules (e.g., carrier tubes); which may then be placed into various well boreholes. Example embodiments may provide waste-capsules capable of containing and disposing of waste generated from spent nuclear fuel, including means for harvesting the nuclear waste from cooling pools and operationally processing the waste fuel assemblies for inclusion in the waste-capsules with various engineered barriers; along with storage in horizontal well boreholes drilled into closed deep geologic formations.
	description	Field of the Invention The present invention relates to a radiation generating tube, and a radiation generating apparatus including the radiation generating tube. Description of the Related Art Needs for small and lightweight medical modality with portability have been increasing with changing of social conditions such as improvement in the home medical care system and expansion of the range of treatment in emergency medical system. To respond to these needs, with developing of analysis diagnostic techniques in the medical field, various medical modalities have been developed. Radiation imaging apparatuses having a radiation source are, due to the sizes of the apparatuses, mainly fixed and installed in hospitals and medical testing facilities. Such radiation generating apparatuses having the radiation source are also required to be reduced in size and weight to use them as modalities applicable to home medical care and emergency medical care in disasters, accidents, and the like. Factors determining the weight and size of radiation generating apparatuses include “radiation generation efficiency” and “shielding member”. The “radiation generation efficiency” means a radiation output intensity to kinetic energy of incident electrons, and a low conversion efficiency of the radiation generation efficiency has been a problem in size reduction and weight reduction. By increasing the radiation generation efficiency, size reduction and weight reduction of a drive circuit and a radiation member constituting a large part of a radiation generating apparatus in the volume and mass can be achieved. The “shielding member” means heavy metallic parts disposed around the whole container of a radiation generation apparatus to prevent emission of radiation except for emission in a direction of necessary radiation flux. The shielding member is disposed to surround a radiation source, and therefore it increases the volume of the radiation generating member, which in turn increases the weight and size of the radiation generating apparatus. As a method for increasing the “radiation generation efficiency”, a method of replacing a target from a reflection type target to a transmission type target has been proposed. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-545840 discusses a technique to increase “radiation generation efficiency” by a factor of 1.5 by replacing a conventional rotating-anode-type reflection-type target with a rotating-anode-type transmission-type target, and, in the same rotation conditions, to increase a peak of an electron injection amount by a factor of 1.3. Further, in radiation generating apparatuses used for living body diagnosis in the medical field, a technique of providing, between the subject and a radiation source, a variable opening type collimator for determining a predetermined exposure range depending on a size of a specimen or a subject is known. In such a radiation generating apparatus, radiation emission to areas other than a predetermined observation field is not useful, and the variable opening type collimator is used to limit the amount of unnecessary exposure to the specimen or subject. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-545840 discusses a radiation generating apparatus having an electron source and a transmission type target separately arranged, in which, at the rear side of the transmission type target, that is, at the side opposite to the electron source of the transmission type target, a collimator for limiting an emission angle of the radiation generated at the transmission type target is provided. Further, Japanese Patent Application Laid-Open No. 2010-115270 discusses a multiple radiation generating apparatus having a plurality of transmission type targets arranged in one-dimensional array or in two-dimensional array. In the multiple radiation generating apparatus disclosed in Japanese Patent Application Laid-Open No. 2010-115270, at the rear side of each of the radiation generating apparatuses, a forward shielding member for limiting an emission angle of the radiation generated at the transmission type target, and a variable opening type collimator for changing the emission direction and the emission angle of the generated radiation are arranged. Further, an anode assembly having a silver target layer, a window material made of beryllium for supporting the target layer, and a window supporting member made of NiCuFe alloy is discussed in an article published by International Centre for Diffraction Data 2004, Advances in X-ray Analysis, Volume 47, entitled “Improvements in low power, end-window, transmission-target X-ray tubes”. Further, the article published by International Centre for Diffraction Data 2004, Advances in X-ray Analysis, Volume 47 entitled “Improvements in low power, end-window, transmission-target X-ray tubes” discusses that radiation due to the window supporting member, the radiation having quality different from that of the radiation due to the target layer contaminates the radiation spectrum. Accordingly, a collimator is disposed between a camera and a radiation generation tube to separate and detect the radiation due to the window supporting member and the radiation due to the target layer. In the known radiation generating apparatuses having the reflection type target, by replacing the reflection type target with the transmission type target, in addition to the above-described increase in “radiation generation efficiency”, an advantage of “low output angle dependence in focal diameter” can be achieved. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-545840 discusses advantages of the transmission type target as compared to the reflection type target, that is, to “reduce apparent output angle dependence in focal diameter” on the target observed from the target side, and to “increase output angle” of the radiation flux. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-545840 further discusses a technique to cut a part of radiation flux having a large emission angle emitted from the transmission type target by the collimator disposed between the object and the radiation target. As described above, an exposure range corresponding to an intended use can be provided by limiting the emission angle of the radiation flux generated from the radiation source having the transmission type target using the collimator. However, the emitted radiation flux may include radiation (referred to as off-focal radiation) generated at spots other than the focal spot of the electron beam formed on the target. The off-focal radiation is generated by irradiating with electrons a member disposed at a place other than the focal spot, the member including a heavy element. Such off-focal radiation decreases the resolution of the radiation diagnostic image, and consequently, the off-focal radiation is to be reduced as much as possible while maintaining the intensity of the radiation within the focal spot. Hereinafter, with reference to FIGS. 7A to 7D, factors of the off-focal radiation generation will be described. FIGS. 7B to 7D are schematic views (upper diagram in each drawing) illustrating generation processes of off-focal radiation generated when an electron beam 5 is emitted toward a target 9 having a target layer 42 on one entire surface of a base member 41 for each track of backscattering reflected electrons, and distribution diagrams (lower diagram in each drawing) illustrating off-focal radiation generation distributions. With reference to FIGS. 7A and 7B, off-focal radiation due to re-entering reflected electrons to target (hereinafter, referred to as off-focal radiation due to re-entering) will be described. In FIG. 7A, the electron beam 5 directly enters the target layer 42 so that a focal diameter 30 is formed on the target layer 42 of the target 9. From the range of the focal diameter 30, a part of the directly entered electron beam 5 scatters backward, and a part of the backscattering electrons re-enters the target layer 42 due to a potential gradient existing between an electron emitting source (not illustrated) and the target layer 42, and becomes re-entering electrons 31. The energy distribution of the backscattering electrons from the target layer 42 includes elastic scattering electrons. The elastic scattering electrons, according to the law of conservation of energy, re-enters the target layer 42 with the same energy as the electron beam 5 directly entering the target layer 42, and generates off-focal radiation 32 at the outside of radiation 51 within focal spot. In FIG. 7A, to facilitate the understanding, the radiation 51 within focal spot and the off-focal radiation 32 are expressed to emit radiation toward the front of the target 9 with emission angles. In actuality, however, although the radiation 51 and the radiation 32 have individual emission angle distributions respectively, the radiation 51 and the radiation 32 are emitted in all directions from the target layer 42. FIG. 7B illustrates a generation mechanism of the off-focal radiation due to re-entering radiation and a distribution of the radiation generation area. In FIG. 7B, η(y) is a radiation intensity distribution due to re-entering reflected electrons to the target, and y shows a relative position of the target layer 42 in the in-plane direction. The radiation intensity distribution η(y) of the off-focal radiation due to re-entering radiation exceeds the focal diameter 30 due to direct incident electrons and is shown as a broad distribution 55. As described above, the off-focal radiation due to re-entering reflected electrons generates, at the outside of the focal spot due to the direct incident, off-focal radiation having a diameter larger than the focal diameter 30. With reference to FIG. 7C, off-focal radiation due to target incidence reflected electrons to backward shielding member (hereinafter, referred to as off-focal radiation due to the backward shielding member) will be described. FIG. 7C illustrates a generation mechanism of the off-focal radiation due to the backward shielding member and a distribution of the radiation generation area. FIG. 7C is similar to FIGS. 7A and 7B in that the electron beam 5 directly enters the target layer 42 to form the focal diameter 30 on the target layer 42 of the target 9. FIG. 7C differs from FIGS. 7A and 7B in that the arrangement includes a backward shielding member 40 located in a rearward position with respect to the target 9, that is, located at the side of the electron emitting source (not illustrated) as a peripheral structure of the target 9. In FIG. 7C, from the range of the focal diameter 30 due to the directly entering electron beam 5, backscattering reflected electrons 33 are generated, and a part of the reflected electrons 33 enters the backward shielding member 40. The backward shielding member 40 is a member containing a heavy metal, and generates radiation in response to reception of the entering reflected electrons 33. A part of the generated radiation is emitted toward the front of the target 9. As a result, as illustrated in the lower diagram of FIG. 7C, an off-focal radiation intensity distribution ξ(y) is generated to have peaks at positions corresponding to the inner wall of the backward shielding member 40. In FIG. 7C, ξ(y) is a radiation intensity distribution due to the target incidence reflected electrons to the backward shielding member, and y shows a relative position of the target layer 42 in the in-plane direction. With reference to FIG. 7D, off-focal radiation due to target incidence of re-entering reflected electrons of target reflected electrons to the backward shielding member (hereinafter, referred to as off-focal radiation due to re-entering reflected electrons) will be described. FIG. 7D illustrates a generation mechanism of the off-focal radiation due to re-entering reflected electrons and a distribution of the radiation generation area. FIG. 7D is similar to FIG. 7C in that the electron beam 5 directly enters the target layer 42 to form the focal diameter 30 on the target layer 42 of the target 9, and the arrangement includes the backward shielding member 40 located in the rearward position with respect to the target 9 as a peripheral structure of the target 9. In FIG. 7D, from the range of the focal diameter 30 due to the directly entering electron beam 5, backscattering reflected electrons 33 are generated, and a part of the reflected electrons 33 enters the backward shielding member 40. Similar to the generation mechanism of the off-focal radiation due to backward shielding member, the backward shielding member 40 generates radiation in response to reception of the entering reflected electrons 33 and a part of the entered electrons elastically scatters. A part of the elastically scattering electrons (re-reflected electrons 34) re-enters the target layer 42. As a result, as illustrated in the lower diagram of FIG. 7D, a broad off-focal radiation intensity distribution ζ(y) is generated to have peaks at positions corresponding to the inside of the inner wall of the backward shielding member 40. In FIG. 7D, ζ(y) is a radiation intensity distribution due to the target incidence of the re-reflected electrons of the target reflected electrons to the backward shielding member 40, and y is a relative position of the target layer 42 in the in-plane direction. The individual radiation intensity distributions η(y), ξ(y), and ζ(y) are observed by a radiation detector (not illustrated) disposed in front of the target 9, that is, at the side of the base member 41 of the target 9. The off-focal radiation to be solved in the present invention is generated due to at least one of the three types of off-focal radiation generated depending on a scattering angle θbs of the backscattering electrons of the target layer 42, an arrangement, and a material of the backward shielding member. The backscattering electrons have a continuous scattering angle probability distribution in the range of 0 degrees≦θbs<90 degrees, and consequently, normally, the three types of off-focal radiation are generated at the same time. As described above, at least one embodiment of the present invention is directed to a radiation generating apparatus capable of reducing each of the off-focal radiation due to the three factors while maintaining the advantages of high power performance, and the small and lightweight properties of the radiation generating apparatus having the transmission target. Further, the present invention is directed to providing a radiation imaging apparatus having a radiation generating apparatus reducing the off-focal radiation and capable of obtaining a high-resolution shot image. In the description of the above-described “off-focal radiation due to re-entering radiation” with reference to FIGS. 7A and 7B, to facilitate understanding, the backward shielding member 40 is not illustrated, however, in a target peripheral structure having the tubular backward shielding member 40, similarly to FIGS. 7C and 7D, the off-focal radiation due to re-entering radiation is generated. According to an aspect of the present invention, a radiation generating apparatus include a radiation generation tube including an electron emitting source having an electron emitting member, a target having a target layer receiving emission of an electron beam emitted from the electron emitting member and generating radiation, and a base member supporting the target layer and transmitting the radiation, in which the electron emitting source and the target layer are disposed to face each other, a tubular backward shielding member having an electron passing hole facing the target layer at one end, located at the electron emitting source side of the target, and connected to the periphery of the base member. The radiation generating apparatus further includes a collimator having an opening for defining an angle for extracting the radiation at the opposite side of the electron emitting source side of the target, and an adjusting device connected to the collimator, and configured to vary an opening diameter of the opening, wherein the target layer has a portion separated from a connection portion of the base member and the backward shielding member at the periphery. Further features of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. With reference to FIGS. 1A to 1C, a basic structure of a radiation generating apparatus according to an exemplary embodiment of the present invention will be described. FIG. 1A is an overall view illustrating a radiation generating apparatus according to the present exemplary embodiment. Further, FIG. 1B illustrates a structure of a target applicable to the radiation generating apparatus according to the present exemplary embodiment. Further, FIG. 1C illustrates a collimator applicable to the radiation generating apparatus according to the present exemplary embodiment. In present exemplary embodiment, a radiation generating apparatus 20 includes a radiation generation unit 18 having a radiation generation tube 1, and an objective unit 19 having a collimator 23. With reference to FIG. 1A, the radiation generation unit 18 according to the present exemplary embodiment is described. The radiation generation unit 18 according to the present exemplary embodiment includes the radiation generation tube 1, and a storage container 16 for storing the radiation generation tube 1. The radiation generation unit 18 can further includes, in the inside 43 of the storage container 16, a drive circuit 15 for driving the radiation generation tube 1. The drive circuit 15 can be provided outside of the storage container 16. The radiation generation unit 18 can further include an insulation fluid (not illustrated), in the inside 43 of the storage container 16, to accelerate heat dissipation of the radiation generation tube 1 or the drive circuit 15. The insulation fluid can be perfluoropolymer oil, silicone oil, or transformer oil. For the storage container 16, as a material having high heat resistance and chemical stability, a metallic material such as stainless steel can be used. In terms of radiation performance of the radiation generation unit 18, a high-thermal-conductivity material such as copper can be suitably used. The storage container 16 can include a window 17 for efficiently extracting radiation 11 emitted from the radiation generation tube 1 to the outside of the radiation generation unit. The window 17 can be made of a light element such as graphite. In terms of the thermal conductivity and heat resistance, aluminum, beryllium, diamond-like carbon, or diamond can be preferably used as the window 17 material. The radiation generation tube 1 includes, in an inner space 13 of an envelope 6 in which the inside has been evacuated, at least an electron emitting source 3 having at least an electron emitting member 2. The radiation generation tube 1 includes the target 9 that receives emission of the electron beam 5 from the electron emitting member 2 and generates radiation. The target 9 includes the target layer 42 containing a target material, and the base member 41 that supports the target layer 42. The target 9 is disposed in such a manner that the target layer 42 and the electron emitting source 3 face each other. The target layer 42 can include a target material made of a metal of an atomic number of 26 or greater such as silver, gold, tantalum, molybdenum, or tungsten. As the target material, an appropriate material can be selected in terms of heat resistance, and in consideration of a melting point and thermal conductivity. Hereinafter, with reference to FIG. 1B and FIGS. 2A to 2D, a specific structure of the target 9 will be described. The target 9 illustrated in FIG. 1B shows a cross-sectional view (left diagram) of the target 9 in which the target 9 provided in the radiation generation tube 1 is enlarged, and a plan view of the target 9 taken along the line H-H′ in the cross-section in the left diagram. A periphery 62 of the target layer 42 has a portion separately located from a periphery 61 of the base member 41. Such an arrangement of the target layer 42 enables reduction in generation of “off-focal radiation due to re-entering radiation” described in FIG. 7B and “off-focal radiation due to re-entering reflected electrons” described in FIG. 7D. To reduce at least the two types of off-focal radiation of “off-focal radiation due to re-entering radiation” and “off-focal radiation due to re-entering reflected electrons”, it is preferable to match the size of the target layer 42 to the size of the focal spot of the electron beam. However, practically, in consideration of a distribution of the backscattering angle θbs of backscattering electrons 31, a suitable size of the target layer 42 is larger than the focal spot size of the electron beam, and smaller than the size of the base member 41. Further, in consideration of an alignment deviation to the target layer 42 of the electron beam 5 due to temperature change in an operating condition of the radiation generation apparatus, it is more preferable that the periphery 62 of the target layer 42 is formed in the range from the position 1.25 times of the focal diameter 30 to the position 0.8 times of the periphery 61. More preferably, the periphery 62 of the target layer 42 is formed in the range from the position 1.1 times of the focal diameter 30 to the position 0.9 times of the periphery 61. Further, to prevent charging and electron-beam damage due to the direct electron incident of the electron beam 5 to the base member 41, it is preferable that the diameter of the target layer defined by the periphery of the target layer 42 is larger than the irradiation diameter 30 of the electron beam 5 to be formed on the target layer 42. FIGS. 2A and 2B illustrate modifications of the target 9 illustrated in FIG. 1B. The targets 9 illustrated in FIGS. 2A and 2B differ from the target 9 illustrated in FIG. 1B in that the target layer 42 has portions locally extended from the periphery 62 toward the periphery 61. Both of the targets 9 illustrated in FIGS. 2A and 2B have, similar to the target 9 illustrated in FIG. 1B, a separated area between the periphery 61 of the base member and the periphery 62 separated from the periphery 61 of the base member. In the above-mentioned separated area, a target material containing an element of a high atomic number is not disposed. Consequently, in the separated area, emission of electrons reflected from the area of the electron beam focal spot into the separated area does not cause generation of at least two types of off-focal radiation of “off-focal radiation due to re-entering radiation” and “off-focal radiation due to re-entering reflected electrons”. In the target layer 42 applicable to the radiation generating apparatus according to the present exemplary embodiment, it is not always necessary that the target layer 42 has a certain film thickness, but as in the target 9 illustrated in FIG. 2C, the film thickness of the target layer 42 can be reduced toward the periphery 62. Further, in the present exemplary embodiment, the target layer 42 is not limited to the target layer 42 formed on the surface of the base member 41, for example, the target layer 42 can be embedded in the base member 41 as illustrated in FIG. 2C. The target 9 like that illustrated in FIG. 2C can be formed, for example, according to an ion plating method or an electrochemical method by locally pushing a target material from one surface of the base member 41 into the base member 41. As a supporting method of the target layer 42 with the base member 41, as illustrated in FIG. 2D, at a position separated inwardly from the periphery 61 of the base member 41, the periphery 62 of the target layer 42 can be circularly supported in a diaphragm shape. With reference to FIGS. 2E to 2J, a specific potential regulation structure of the target 9 will be described. FIGS. 2E to 2G illustrate a potential regulation structure, which is not illustrated in the target 9 illustrated in FIG. 1B, as an electrode 45. The electrodes 45 in FIGS. 2E to 2G are formed to be sequentially arranged within areas from the periphery 61 of the base member 41 to the periphery 62 of the target layer 42. The electrodes 45 in FIGS. 2E to 2G differ from each other in the formation areas of the electrodes 45 to the base member 41. The electrode 45 is provided only to regulate the potential of the target layer 42 to an anode potential. Consequently, the electrode 45 can be a conductive material made of a material having a lower atomic number than the atomic number of the target material contained in the target layer 42. For example, aluminum, chromium, titanium, or graphite can be used for the electrode 45. The electrode 45 can be formed to have a film thickness for ensuring conductivity enough to regulate the potential as a lower limit, and a film thickness equal to or thinner than one-tenth of the film thickness of the target layer 42 as an upper limit to reduce the interaction with the incident electrons. For example, the film thickness can be between 1 nm to 1 μm. A film thickness of the electrode 45 between 10 nm to 100 nm enables both more stable potential regulation of the target layer 42 and reduction of the off-focal radiation. As described above, by the arrangement of the electrode 45 formed of a material of a small atomic number and small thickness in the separated area to regulate the potential of the target layer 42 disposed to separate inwardly from the periphery of the base member 41, in the separated area, “off-focal radiation due to re-entering radiation” and “off-focal radiation due to re-entering reflected electrons” can be reduced. Similarly, FIG. 2J illustrates a relation of connection between the electrode 45, which is not illustrated in the target 9 illustrated in FIG. 2B, and the target layer 42. In the target 9 illustrated in FIG. 2(I), the extended portions of the target layer 42 reach the periphery 61 of the base member 41, and the extended portions can be used as a potential regulation structure of the target layer 42. In this structure, it is not necessary to separately provide an electrode. The radiation generation tube 1 further includes the cylindrical backward shielding member 40 located at the electron emitting source side of the target 9 and having an electron incident opening 8. The backward shielding member 40 is disposed at the rear side of the target 9 for at least one purpose of the six purposes described below. The first purpose of the backward shielding member 40 is to reduce electron damage and charging to the structural members of the radiation generation tube such as a cathode, a convergent electrode, and an insulation tube (not illustrated) located in the rearward position with respect to the target 9. The second purpose of the backward shielding member 40 is to reduce radiation damage and malfunction to the structural members of the radiation generation apparatus such as a drive circuit and cooling medium (not illustrated) located in the rearward position with respect to the target 9. The third purpose of the backward shielding member 40 is to accelerate heat radiation of the target 9, that is, to prevent overheating of the target 9. The fourth purpose of the backward shielding member 40 is to prevent radiation leakage to an ambient environment. The fifth purpose of the backward shielding member 40 is to reduce the weight of the radiation generating apparatus by disposing the backward shielding member at a position near a radiation generation area. The sixth purpose of the backward shielding member 40 is to increase an amount of radiation to be emitted toward the front of the target 9. The backward shielding member 40 can be made of a material containing at least a metal of an atomic number of 26 or greater such as copper or iron. To reduce a radiation incident amount to other structures disposed posterior to the target 9, it is preferable that the backward shielding member 40 includes at least a metal of an atomic number of 42 or greater such as silver, gold, molybdenum, tantalum, or tungsten. Further, the backward shielding member 40 includes at least the target material contained in the target layer 42, that is, in a case where the backward shielding member 40 includes a heavy metal material common to the target layer 42, the radiation due to the backward shielding member includes characteristic radiation due to the target layer 42, and thereby the intensity of the radiation to be emitted forward can be increased. The action of increase in the intensity of the radiation to be emitted forward is specifically described. In FIG. 7C, in the radiation intensity distribution ξ(y) of the radiation due to re-entering reflected electrons due to the backward shielding member 40, the radiation in the range overlapping with the focal diameter 30 is added to the intensity of the radiation 51 within focal spot in FIG. 7A, and thereby the radiation intensity can be obtained. In the radiation generating apparatus according to the present exemplary embodiment, the off-focal radiation to be emitted toward the front of the target from positions other than the focal diameter 30 can be reduced, and consequently, the user can optimize the use of the effect of the increase in the radiation within focal spot. The potential of the target 9 according to the present exemplary embodiment is regulated to an anode potential that is higher about 20 kV to 200 kV than the potential of the electron emitting source 3. Further, the target 9 can be electrically connected to a high-tension circuit (not illustrated) via an anode member (not illustrated). The backward shielding member 40 can also serve as an anode member 40, and in such a case, the target 9 can be electrically and mechanically connected to the backward shielding member 40 via a conductive joint material (not illustrated). As the conductive joint material, a brazing filler metal containing silver, tin, or copper as components can be used. The high-tension circuit can be provided in the drive circuit 15. The radiation generation tube 1 according to the present exemplary embodiment includes the envelope 6 having a cathode provided with the electron emitting source 3, an anode provided with the target 9, and an insulating tube for electrically insulating the cathode and the anode. To the insulating tube, the cathode and the anode are fixed with a predetermined distance. The pressure in the inner space 13 of the envelope 6 is reduced to vacuum to a degree electronic irradiation from the electron emitting source 3 to the target 9 can be performed. The pressure in the inner space 13 of the envelope 6 may be reduced to a degree enough to ensure a mean free path of the electron beam 5, and typically, to the range from 1×10−8 Pa to 1×10−4 Pa. To maintain the degree of vacuum, the radiation generation tube 1 can be provided with a getter (not illustrated) exposed in the inner space 13. The electron emitting source 3 according to the present exemplary embodiment is connected to a drive circuit disposed outside of the radiation generation tube 1 via an electric current introduction terminal 4 to enable control of a radiation generation amount to be emitted from the radiation generation tube 1 from the outside of the radiation generation tube 1. The electric current introduction terminal 4 is electrically connected to the drive circuit 15, and further electrically connected to a grid electrode and a convergence electrode (not illustrated) provided to the electron emitting member 2 and the electron emitting source 3. With reference to FIG. 1A, the objective unit 19 according to the present exemplary embodiment is described. The objective unit 19 according to the present exemplary embodiment includes the collimator 23 having movable diaphragms 56 and 57, an adjusting device 52 for varying the size of an opening 53 defined by the movable diaphragms 56 and 57, and the storage container 16 for storing the collimator 23 and the adjusting device 52. The collimator 23 is disposed at the opposite side of the electron emitting source side of the target 9, that is, disposed anterior to the target 9. The collimator 23 shields at least a part of radiation 11 emitted toward the front of the target 9, and allows the rest of the radiation 11 to pass through via an opening 53 toward the front of the collimator 23. In other words, with the opening 53, the collimator 23 defines an angle for extracting the radiation 11 emitted from the target 9 toward the front of the target 9. The objective unit 19 according to the present exemplary embodiment includes the adjusting device 52 being connected to the collimator 23, the adjusting device 52 for varying the opening diameter of the collimator 23. In the present exemplary embodiment, based on a higher-order instruction output from a higher-order instruction unit (not illustrated), or an operation instruction of an operator, the adjusting device 52 moves the movable blades 56 and 57 of the collimator 23 to vary the size of the opening of the collimator 23, that is, the opening diameter. With reference to FIG. 1A and FIGS. 7C and 7D, off-focal radiation reduction action performed by the radiation generating apparatus having the collimator 23 according to the present exemplary embodiment of the present invention will be described. When the radiation generating apparatus illustrated in FIG. 1A is operated, at least a part of backscattering electrons generated at the target layer 42 enters the backward shielding member 40. As a result, due to the backward shielding member 40, at least two types of off-focal radiation of “off-focal radiation due to backward shielding member” and “off-focal radiation due to re-entering reflected electrons” are emitted toward the front of the target 9. The at least two types of the off-focal radiation of “off-focal radiation due to backward shielding member” and “off-focal radiation due to re-entering reflected electrons” have local maximum values in the generation distribution ξ(y) and ζ(y) beyond the focus area formed on the target 9 by the electron beam 5. The collimator 23 performs the reduction action for each of the off-focal radiation generation distributions ξ(y), and ζ(y) of the above-mentioned at least two types of “off-focal radiation due to backward shielding member” and “off-focal radiation due to re-entering reflected electrons”. In summary, the radiation generating apparatus 20 according to the present exemplary embodiment of the present invention has a first feature that the target layer 42 includes the part of the periphery 62 of the target layer 42 separated from the periphery 61 of the base member 41, and a second feature that the adjusting device 52 connected to the adjusting device 52 for varying the opening diameter of the opening 53 of the collimator 23 is provided. The radiation generating apparatus 20 according to the present exemplary embodiment of the present invention can, by the first feature, reduce at least “off-focal radiation due to re-entering radiation” and “off-focal radiation due to re-entering reflected electrons”, and by the second feature, reduce at least “off-focal radiation due to backward shielding member” and “off-focal radiation due to re-entering reflected electrons”. With reference to FIGS. 3A and 3B, in an arrangement having a tubular forward shielding members 46 located in front of the target 9, a relationship in the arrangement of the collimator 23, the forward shielding members 46, and the target 9 for further increasing the effects of the action implemented by the second feature in the present exemplary embodiment of the present invention will be described. FIG. 3A illustrates, in the radiation generating apparatus having the target 9, the forward shielding members 46, and the collimator 23, a condition Φmin for an opening diameter for preventing reduction of the radiation within focal spot as much as possible while reducing the off-focal radiation. In other words, for the opening diameter Φ of the collimator 23, by including at least the Φmin in a variable range of the opening diameter Φ of the opening 53, while reducing the off-focal radiation, the reduction in the radiation within focal spot can be prevented as much as possible. Consequently, in the radiation generating apparatus according to the present exemplary embodiment, a condition for the opening diameter of the collimator 23 for preventing the reduction of the radiation within focal spot as much as possible while reducing the off-focal radiation is to satisfy the following general formula (1).Φmin≦2A+2×(B−A)×(C+D)/C, Φ≧Φmin formula(1),where 2A is an electron beam irradiation diameter to be formed on the target layer, 2B is a tube outgoing diameter, C is a distance between a virtual plane for defining an inner diameter of a tube outgoing opening 58 and the target layer, and D is a distance between a virtual plane for defining an opening diameter of the collimator, and the virtual plane for defining the inner diameter of the tube outgoing opening 58. On the other hand, FIG. 3B illustrates, in the radiation generating apparatus having the target 9, the forward shielding members 46, and the collimator 23, a condition Φmax for an opening diameter for substantially eliminating reduction of the radiation within focal spot due to the collimator 23 while reducing the off-focal radiation to a minimum. In other words, for the opening diameter Φ of the collimator 23, by including at least the Φmax in the variable range of the opening diameter Φ of the opening 53, while reducing the off-focal radiation to a minimum, the reduction in the radiation within focal spot due to the collimator 23 can be eliminated. Consequently, in the radiation generating apparatus according to the present exemplary embodiment, a condition for the opening diameter of the collimator 23 for substantially eliminating the reduction of the radiation within focal spot due to the collimator 23 while reducing the off-focal radiation to a minimum is to satisfy the following general formula (2).Φmax≧−2B+2×(A+B)×(C+D)/C, Φ≦Φmax formula (2)In FIGS. 3A and 3B, for the description of the conditions in the Y direction of the opening 53, the Y-X planes are representatively described. In a case of the collimator 23 having the opening 53 of a shape other than the circular shape having an anisotropy, in a plurality of directions i (i=0, 1, 2 . . . ) for representatively defining an opening diameter, to each of, or a part of the directions i, the general formula (1) or the general formula (2) can be applied. With reference to FIGS. 4A to 4F, modifications of a shielding member 7 to be applied to the radiation generating apparatus according to the present exemplary embodiment of the present invention, the target-forward shielding member distance C, the inner diameter 2B to be defined by the tube outgoing opening 58 of the forward shielding member, and the electron beam irradiation diameter 2A will be described. FIGS. 4D to 4F illustrate the target 9 and the peripheral structure of the target 9 in which the tubular forward shielding member 46 is disposed anterior to the target 9 and posterior to the collimator 23. The tubular forward shielding member 46 according to the present exemplary embodiment shields, from the radiation generated at the target layer 42, at least a part of the radiation 11 emitted toward the front of the target 9, and allows the rest of the radiation 11 to pass through via the opening 58 toward the front. In the present exemplary embodiment, the target-forward shielding member distance C is determined by a distance between a virtual plane IF for defining an inner diameter of the tube outgoing opening 58 of the forward shielding member 46, and an interface between the target layer 42 and the base member 41. The virtual plane IF according to the present exemplary embodiment is determined as follows. First, the point on the target layer 42 where the perpendicular line virtually extended from the center of the focal diameter of the electron beam 5 that is direct incident electrons to the interface IT between the target layer 42 and the base member 41 intersects with the interface IT is determined to be a reference point. The reference point is the center of the electron irradiation region of the target 9. Next, a geometrical condition for a virtual conical surface SC to contact the forward shielding member 46 is to be defined. The virtual conical surface SC is a conical surface of a virtual cone having the reference point as a vertex and a viewing angle from the reference point toward the opening of the tubular forward shielding member 46 as a spray cone angle, the virtual conical surface SC extending in a direction increasing a distance from the target 9. Then, within the range the virtual conical surface SC contacts the forward shielding member 46, a virtual plane including a region farthest from the target 9 is defined as IF. A distance between the defined IF and the interface between the target layer 42 and the base member 41 is the target-forward shielding member distance C. Further, the bottom surface of the cone formed by the defined IF and the virtual conical surface SC is defines as the tube outgoing opening 58, and the inner diameter of the tube outgoing opening 58 is determined to be the tube outgoing opening diameter 2B. In a case where the bottom surface is a circle, the diameter of the bottom surface is to be 2B, and in a case where the bottom surface is an ellipse, 2B has a length distribution from the minor axis to the major axis, and in such a case, the minor axis and the major axis can be used as representative values of the outgoing opening diameter 2B. In a case of a forward shielding member shape forming a cone having a bottom surface of a polygonal shape, inner diameters of the outgoing opening corresponding to a minimum angle and a maximum angle of the vertical angles of the cone respectively can be used as representative values of a minimum value and a maximum value of the outgoing opening diameter 2B. With reference to FIGS. 5A to 5E, the collimator applicable to the radiation generating apparatus according to the present exemplary embodiment of the present invention will be described. FIG. 5A is a plan view illustrating the collimator 23 illustrated in FIG. 1C viewed from the back, that is, from the target 9 direction. FIGS. 5B to 5E are cross-sectional views of the collimator 23 taken along the guide lines K-K′, L-L′, M-M′, and N-N′ in FIG. 5A. The collimator 23 may have a density and a thickness enough to shield the radiation emitted from the target 9 illustrated in FIG. 1A, and for the collimator 23, a metallic material can be used. To further reduce the size of the radiation generating apparatus, the movable diaphragms 56 and 57 can contain a heavy metal such as zirconium, molybdenum, tantalum, or tungsten to reduce the thickness of the collimator 23 in the optical axis direction. As illustrated in FIG. 1A, in a case where a matrix shaped collimator 23 is formed with a plurality of the movable diaphragms 56 and 57, each movable blade has a finite thickness, and consequently, both of the above-described target-collimator distance C+D, and the forward shielding member-collimator distance D can have a distribution in the circumferential direction surrounding the opening 53 viewed from the center portion of the opening 53. For example, as illustrated in FIG. 5A, in a case where the collimator 23 has a matrix shape forming the rectangle opening 53, an opening diameter ΦZ in the Z direction illustrated in FIG. 5E is defined by a pair of the movable blades 57, and an opening diameter ΦY in the Y direction illustrated in FIG. 5C is defined by a pair of the movable blades 56. In the present exemplary embodiment, a virtual plane PZ defining the opening diameter ΦZ in the Z direction is separated from the collimator 23 or the forward shielding member by a thickness t of the movable blade 56 in the X direction as compared to a virtual plane PY defining the opening diameter ΦY in the Y direction. In the present exemplary embodiment, to prevent the off-focal radiation from emitting to the radiation detector 27 side, it is preferable that ΦZ satisfies the above-mentioned general formula (1), and the ΦY satisfies the general formula (2). In other words, it is preferable that the following general formulas (3) and (4) are satisfied, and further the general formula (5) is satisfied to obtain a high passage rate of the radiation within focal spot spreading in the Y direction of the opening 53 at the opening 53.ΦZ≦ΦY formula (3),ΦZmin≦2A+2×(B−A)×(C+DPZ)/C,ΦZ≧ΦZmin formula (4),ΦYmax≦−2B+2×(A+B)×(C+DPY)/C,ΦY≦ΦYmax formula (5),where ΦZmin is a minimum value in the variable range of the opening 53 in the Z direction, ΦYmax is a maximum value in the variable range of the opening 53 in the Y direction, DPZ is a distance between the forward shielding member and a virtual plane PZ defining the opening diameter ΦZ of the collimator 23, and DPY is a distance for defining the opening diameter ΦY of the collimator 23. With respect to a condition satisfying the general formulas (3) and (4), in other words, in a case where the opening 53 of the collimator has a rectangular opening shape having a one side of a length P, and the other side of a length Q, a minimum value of the opening diameter to be defined by the mechanism for varying the opening diameter of the opening 53 corresponds to a minimum value of the length of P or Q not longer than the other one. Similarly, with respect to a condition further satisfying the general formula (5), in other words, in a case where the opening 53 of the collimator has a rectangular opening shape having a one side of a length P, and the other side of a length Q, a maximum value of the opening diameter to be defined by the mechanism for varying the opening diameter of the opening 53 corresponds to a maximum value of the length of P or Q not shorter than the other one. Further, in the present exemplary embodiment, to prevent the off-focal radiation spreading in the Y direction of the opening 53 from emitting to the radiation detector 27 side, it is more preferable to satisfy the following general formula (6), and to obtain a high passage rate of the radiation within focal spot spreading in the Z direction of the opening 53 at the opening 53, it is more preferable to satisfy the general formula (7).ΦYmin≦2A+2×(B−A)×(C+DPY)/C,ΦY≧ΦYmin formula (6),ΦZmax≧−2B+2×(A+B)×(C+DPZ)/C,ΦZ≦ΦZmax formula (7),where, ΦYmin is a minimum value in the variable range of the opening 53 in the Y direction, and ΦZmax is a maximum value in the variable range of the opening 53 in the Z direction. As in the present exemplary embodiment, in the collimator defining different opening diameters in different directions at positions of different distances from the target, as described in the present exemplary embodiment, to reduce the off-focal radiation, it is preferable to arrange the movable blades 57 defining a larger opening diameter ΦY closer to the target as compared to the movable blades 56 defining a smaller opening diameter ΦZ. The collimator 23 applicable to the present exemplary embodiment of the present invention is not limited to the above-described matrix shape forming the rectangular opening 53. Alternatively, modifications include, for example, the collimator 23 of an iris diaphragm shape (not illustrated) formed by radially arranging a plurality of diaphragm blades to form a substantially circular opening, and the collimator 23 formed by arranging diaphragm blades in a separated state in an optical axis direction. With reference to FIGS. 6A and 6B, as another exemplary embodiment of the present invention, a radiation imaging apparatus having a radiation generating apparatus according to an exemplary embodiment of the present invention and a radiation detector will be described. FIG. 6A illustrates an exemplary embodiment of a radiation imaging apparatus 60 having an imaging field acquisition unit 59 disposed to provide an image acquisition area in the direction to face a radiation detector 47. FIG. 6B illustrates a modification of the radiation imaging apparatus 60 having a sighting optical system 44 for providing an exposure field. With reference to FIG. 6A, an exemplary embodiment including the adjusting device 52 for varying an opening diameter of the collimator 23 and the imaging field acquisition unit 59 will be described. In the present exemplary embodiment, the imaging field acquisition unit 59 includes a mirror 21 disposed in a tilted state to the emission center axis of the radiation 11, and an optical camera 49 having an imaging field toward the mirror 21. In such an arrangement, the optical camera 49 can define the imaging field toward the radiation detector 47. To align the imaging field and the exposure field, it is preferable that the position of the optical camera 49 to the mirror 21 is a conjugate position to the focal spot on the target. The adjusting device 52 for varying the opening diameter of the collimator 23 is connected to the optical camera 49 via an opening diameter instruction unit 48. The present exemplary embodiment of the present invention includes an arrangement in which the imaging field acquisition unit 59 is disposed outside of an objective lens barrel 24. In the present exemplary embodiment, based on an acquired image acquired by the optical camera 49, the imaging field acquisition unit 59 determines a detection range of the radiation detector 47 or a size of a region of interest of a test object 25. Then, based on the detection range of the radiation detector 47 or the size of the region of interest of the test object 25, the imaging field acquisition unit 59 can send information including the size of the exposure field to the opening diameter instruction unit 48. The opening diameter instruction unit 48, based on the received information including the size of the exposure field, sends an instruction signal for specifying the opening diameter of the collimator 23 to the adjusting device 52. More specifically, a method for determining a size of the exposure field by the opening diameter instruction unit 48 is described. In the present exemplary embodiment, before a timing of determining an exposure field, the opening diameter instruction unit 48, in advance, issues an instruction to the adjusting device 52 to fully open the opening of the collimator 23. By performing the step of fully opening the opening of the collimator 23, information including a virtual exposure field corresponding to an area wider than a region of interest can be sent to the opening diameter instruction unit 48. Then, the opening diameter instruction unit 48 provides the virtual exposure field to an operator (not illustrated) on a display screen (not illustrated). The operator, from the provided virtual exposure field, acquires the information including the exposure field corresponding to the region of interest by an input unit (not illustrated), and sends the acquired exposure field information to the opening diameter instruction unit 48. The opening 53 of the collimator 23 at the timing of acquiring the virtual exposure field with the optical camera 49 is not limited to the fully open condition, and an opening of a size including the region of interest of the subject 25, and the size enough to acquire a region wider than the region of interest is to be ensured. The image to be acquired by the optical camera 49 can be a visible light image or an image acquired using other wave lengths such as an infrared light image. With reference to FIG. 6B, an exemplary embodiment including the adjusting device 52 for varying an opening diameter of the collimator 23 and the sighting optical system 44 will be described. In FIG. 6B, similarly to the present exemplary embodiment illustrated in FIG. 6A, the adjusting device 52 for varying an opening diameter of the collimator 23 is connected to the opening diameter instruction unit 48. In the present exemplary embodiment, the sighting optical system 44 includes the mirror 21 disposed in a tilted state to the emission center axis of the radiation 11, and a light source 22 having an emission direction toward the mirror 21. The emission wavelength of the light source 22 is not limited to visible light, and ultraviolet light can be used. As the light source 22, it is preferable to employ a visible light source to directly provide an exposure range to a subject or an operator. In the present exemplary embodiment, the objective unit 19 can include the objective lens barrel 24 for storing at least the mirror 21 and the light source 22. To ensure an illuminance contrast of an area to which exposure is provided with respect to an area where the exposure is not provided, it is preferable to make the objective lens barrel 24 with an opaque member to the wavelength of the light provided by the objective unit. Further, to ensure an illuminance contrast of an area where exposure is provided with respect to an area where the exposure is not provided, it is preferable to provide, to the inner surface of the objective lens barrel 24, a member having a low reflectivity to the wavelength of the light provided by the objective unit to reduce diffused reflection. In the present exemplary embodiment, based on recognition of an operator (not illustrated) by visual observation on an exposure range provided by the sighting optical system 44 in the direction toward the radiation detector 47, the operator can output an instruction signal instructing an opening diameter of the collimator 23 to the opening diameter instruction unit 48. In the present exemplary embodiment, the opening diameter instruction unit 48, based on the detected region of the radiation detector 47, or the size of the interest region of the subject, sends an instruction signal for specifying the opening diameter of the collimator 23 to the adjusting device 52. As a modification of the present exemplary embodiment illustrated in FIGS. 6A and 6B, a sensor (not illustrated) further provided to the radiation detector 47 can specify the size of the exposure range or the subject 25. For example, to the opening diameter instruction unit 48, information about a size of an exposure range or a subject can be sent via a detector control circuit 50 to control the opening of the collimator 23. The above-mentioned sensor can be an optical sensor having a light-receiving sensitivity to the irradiation wavelength of the irradiation light source, or can be a piezoelectric sensor or a temperature sensor to determine a size of a subject. In the present exemplary embodiment, it is not limited to dispose the sensor (not illustrated) in the radiation detector 47, but the sensor can be disposed between the subject and the radiation generating apparatus 20, or before or after the radiation detector 47 with respect to the irradiation direction of the radiation 11. The radiation generating apparatus according to the above-described exemplary embodiments of the present invention has the transmission type target and the backward shielding member, and consequently, in addition to the advantages of high output, small and lightweight, battery-powered, and portability, the following effects can be further provided. The radiation generating apparatuses according to the above-described exemplary embodiments of the present invention can reduce effective focal spot increase due to backscattering reflected electrons at a target. This enables prevention of decrease in the resolution of an acquired image in applications of the radiation generating apparatuses according to the present exemplary embodiments of the present invention to radiation imaging apparatuses for medical diagnosis, and industrial non-destructive tests. As a result, radiation diagnosis at high resolutions can be performed. Consequently, according to the present exemplary embodiments of the present invention, the radiation generating apparatuses and radiation imaging apparatuses provided with high-power radiation emission and small and lightweight properties, and implementing high-resolution radiation image acquisition can be provided. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. This application claims the benefit of Japanese Patent Application No. 2012-187615 filed Aug. 28, 2012, which is hereby incorporated by reference herein in its entirety.
048790869	summary	BACKGROUND OF THE INVENTION This invention is directed to a reactivity control system for a light water breeder reactor (LWBR). In particular, the LWBR reactivity control comprises a stationary seed-blanket core arrangement comprising a radial arrangement of the fuel into a pattern of discrete seed regions that contain ThO.sub.2 -UO.sub.2 fuel pellets and discrete blanket regions that contain pure thorium dioxide fuel pellets. The United States Government has rights in this invention pursuant to Contract No. DE-AC12-76-SN00052 between the U.S. Department of Energy and the General Electric Company. The continuous, world-wide growth of nuclear power based on current light water reactors will deplete readily obtainable supplies of the fissile fuel isotope uranium-235. While authoritative studies may disagree on the expected timing of this event, there is a general agreement that, to pursue nuclear power as a major energy source, the nuclear fuel cycle must take advantage of the potential energy available in the abundant fertile fuel isotopes, uranium-238 and/or thorium-232. Reactor technology in coming decades must shift away from the current light water reactor with a once-through fuel cycle toward more fuel efficient concepts, including fuel recycle, high energy converter reactors and breeder reactors. Light water moderated converter reactors or breeder reactors using the thorium-232/uranium-233 fuel cycle are looked upon as attractive options for future nuclear reactors. The attractiveness of the thorium fuel cycle in a light water reactor derives from three major considerations; (1) the core, reactor equipment, primary system and balance of the plant are all based on the well-established technology of light water reactors; (2) fuel utilization is better than for the uranium/plutonium fuel cycle in a similar light water reactor application with recycled fuel and the thorium fuel cycle can achieve a self-sustaining breeder reactor system; (3) existing pressurized water reactor plants could be refitted with thorium fuel cycle converter cores, although the highest level of fuel utilizations are probably not achievable at full plant power ratings. The atomic Energy Commission and its successor governmental agencies, ERDA and the Department of Energy, has attempted to demonstrate the potential of the thorium fuel cycle in light water moderated reactors from the mid-1970's. Various concepts are being explored, including pre-breeder, converter and advance breeder reactors including a scale-up of the Shippingport reactor operated by the Duquesne Light Company. A very recent development in this technology has advanced the concept that a practical commercial scale breeder may be made which does not rely upon a separate source, such as a pre-breeder and converter reactor to provide its initial load of fissile uranium-233. The concept includes a breeder reactor plant which becomes its own pre-breeder by using fuel elements of different dimensions for the initial pre-breeder core cycles. The present invention is directed to a reactivity control system for the breeder concept of this type of pre-breeder/breeder reactor system. The reactivity control system for the breeder concept proposed in this application must perform all the functions of the reactivity control system in a commercial pressurized water reactor (PWR) but, in addition, it must perform those functions while minimizing the loss of neutrons to neutron poisons or other parasitic materials. For example, a typical present generation commercial PWR control system consists of soluble boron used in the primary coolant and poison control rod assemblies used for shutdown, regulating, and axial power shaping. This control system has the advantage of good axial and radial power distributions due to the uniform poisoning effect of soluble boron, but has the disadvantage of poor neutron economy due also to the presence of a relatively large amount of soluble boron. Accordingly, this type of control system is not conductive to a light water breeder reactor concept because of poor neutron economy present when one uses large quantities of boron. The Shippingport light water breeder reactor control system consists of a movable fuel control. In this system, each active module of the core contains a central movable fuel assembly surrounded by a stationary blanket assembly. Reactivity control is accomplished by varying the axial position of the movable seed assemblies relative to the surrounding stationary blanket assembly. For a typical module, the movable speed volume is approximately 30% of the total active module volume. The Shippingport LWBR control system has the advantage of good neutron economy because it adjusts reactivity by using variable seed positions rather than a poison material. However, due to the movable fuel, the Shippingport LWBR system results in a higher axial power peaking not present in the commercial PWR. The reactivity control system of the present invention is able to achieve the neutron economy of the movable fuel Shippingport LWBR while maintaining the axial power peaking properties of commercial PWRs. Accordingly, the reactivity control system of the present invention is able to incorporate the advantages of the PWR control system and the LWBR control system of Shippingport without their attendant disadvantages. SUMMARY OF THE INVENTION It is the primary object of the present invention to provide a reactivity control system for a LWBR which meets all the control system requirements set forth by present PWRs. It is another object of the present invention to provide a reactivity control system for a LWBR which maximizes absorption in fertile material and minimizes the absorption in poison material. It is a further object of the present invention to provide a reactivity control system for a LWBR which minimizes axial and radial power peaking. It is still another object of the present invention to provide a reactivity control system for a LWBR which maximizes the use of current light water reactor technology. Additional objectives, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. To achieve the foregoing and other objectives and in accordance with the purpose of the present invention, as embodied and broadly described herein, the reactivity control system of the present invention comprises a reactor core having a stationary seed-blanket arrangement comprising a plurality of symmetrical, contiguous, substantially hexagonal-shaped regions. Each of these regions has a central and peripheral blanket area juxtapositioned an annular seed area and bounding the seed area, The central and peripheral blanket areas contain a plurality of blanket fuel rods wherein the blanket fuel rods contain thoria fuel pellets. The annular seed area contains a plurality of seed fuel rods and a plurality of movable thoria shim control rods. The seed fuel rods contain a mixture of thoria and urania fuel pellets. The term stationary seed-blanket arrangement is used to signify that all seed and blanket fuel rods are fixed in the core as are the fuel rods in a typical, commercial PWR core. These rods do not move as do the seed rods in the Shippingport LWBR. In the preferred embodiment of the reactivity control system of the present invention, the cross section of said reactor core contains about 37 contiguous, symmetrical, substantially hexagonal-shaped regions. In a further preferred embodiment of the reactivity control system of the present invention, the movable thoria shim control rods are located substantially in the center of the annular seed area of the nuclear reactor core. In a still further preferred embodiment of the present invention, the reactivity control system also includes poison shutdown rods, poison regulating rods, axial power shaping rods, and a soluble coolant containing boron. It is, of course, understood that each of these components in the reactivity control system performs in its known conventional manner. The reactivity control system of the present invention combines the advantages of the PWR control system and the Shippingport LWBR control system previously described. The reactor control system of the present invention, like the commercial PWR control system, has the advantage of good axial and radial distributions, but does not have the disadvantage of poor neutron economy. The reactivity control system of the present invention has the advantage of good neutron economy similar to the Shippingport LWBR system but because of the stationary seed-blanket core concept of the present invention can nearly flatten the variation in the lifetime activity and, in itself, almost eliminates the need for soluble boron at the full power operation. Accordingly, it can be seen that the reactivity control system of the present invention incorporates the best features of the pressurized water system and the Shippingport light water breeder reactor system without their attendant disadvantages. The reactor system of the present invention has good neutron economy while maintaining axial power peaking similar to a commercial pressurized water system.
	description	An integrated circuit (“IC”) is a device (e.g., a semiconductor device) or electronic system that includes many electronic components, such as transistors, resistors, diodes, etc. These components are often interconnected to form multiple circuit components, such as gates, cells, memory units, arithmetic units, controllers, decoders, etc. An IC includes multiple layers of wiring that interconnect the IC's electronic and circuit components. Design engineers design ICs by transforming logical or circuit descriptions of the ICs' components into geometric descriptions, called design layouts. Design layouts typically include (1) circuit modules (i.e., geometric representations of electronic or circuit IC components) with pins and (2) interconnect lines (i.e., geometric representations of wiring) that connect the pins of the circuit modules. In this fashion, design layouts often describe the behavioral, architectural, functional, and structural attributes of the IC. To create design layouts, design engineers typically use electronic design automation (“EDA”) applications. These applications provide sets of computer-based tools for creating, editing, analyzing, and verifying design layouts. The applications also render the layouts on a display device or to storage for displaying later. Fabrication foundries (“fabs”) manufacture ICs based on the design layouts using a photolithographic process. Photolithography is an optical printing and fabrication process by which patterns on a photolithographic mask (i.e., “photomask,” or “mask”) are imaged and defined onto a photosensitive layer coating a substrate. To fabricate an IC, photomasks are created using the IC design layout as a template. The photomasks contain the various geometries or shapes (i.e., features) of the IC design layout. The various geometries or shapes contained on the photomasks correspond to the various base physical IC elements that comprise functional circuit components such as transistors, interconnect wiring, vertical interconnect access (via) pads, as well as other elements that are not functional circuit elements but are used to facilitate, enhance, or track various manufacturing processes. Through sequential use of the various photomasks corresponding to a given IC in an IC fabrication process, a large number of material layers of various shapes and thicknesses with various conductive and insulating properties may be built up to form the overall IC and the circuits within the IC design layout. As more circuit features are packed into an IC design layout (e.g., manufacturing processes at feature sizes of 22 nm and below), the resolution of the photolithographic process makes it extremely difficult to fabricate the geometries or shapes on a single lithography mask. The difficulty stems from constraining factors in traditional photolithographic processes that limit the effectiveness of current photolithographic processes. Some such constraining factors are the lights/optics used within the photolithographic processing systems. Specifically, the lights/optics are band limited due to physical limitations (e.g., wavelength and aperture) of the photolithographic process. Therefore, the photolithographic process cannot print beyond a certain minimum width of a feature, minimum spacing between features, and other such physical manufacturing constraints. For a particular layer of the IC fabrication process, the pitch specifies the sum of the width of a feature and the space on one side of the feature separating that feature from a neighboring feature on the same layer. The minimum pitch for a layer is the sum of the minimum feature width and the minimum spacing between features on the same layer. Depending on the photolithographic process at issue, factors such as optics and wavelengths of light or radiation restrict how small the pitch may be made before features can no longer be reliably printed to a wafer or mask. As such, the smallest size of any features that can be created on a layer of an IC is limited by the minimum pitch for the layer. FIG. 1 illustrates a typical pitch constraint of a photolithographic process. In FIG. 1, a pitch 110 acts to constrain the spacing between printable features 120 and 130 of a design layout. While other photolithographic process factors such as the threshold 140 can be used to narrow the width 150 of the features 120 and 130, such adjustments do not result in increased feature density without adjustments to the pitch 110. As a result, increasing feature densities beyond a certain threshold is infeasible via a pitch constrained single exposure process. To enhance the feature density, the shapes on a single layer can be manufactured on two different photolithographic masks. This approach is often referred to as “Double Patterning Lithography (DPL)” technology. FIG. 2 illustrates an example of this approach. In FIG. 2, a design layout 205 specifies three features 210-230 that are pitch constrained and therefore cannot be photolithographically printed with a conventional single exposure process. Analysis of the characteristics (e.g., the band limitation) of the available photolithographic process and of the design layout 205 results in the decomposition of the design layout 205 into a first exposure 240 for printing features 210 and 230 and a second exposure 250 for printing feature 220. As such, the features 210 and 230 are assigned to a first photomask for printing during the first exposure 240 and feature 220 is assigned to a second photomask for printing during the second exposure 250. FIGS. 3A and 3B illustrate two different manners of using DPL technology. FIG. 3A illustrates sending different shapes of a layer to two different masks. In contrast, FIG. 3B illustrates decomposing one shape into several smaller shapes to send them to two different masks. Specifically, FIG. 3A illustrates sending five shapes 301-305 of a design layout 300 to two different masks. The shape pairs of the shapes 301 and 302; the shapes 302 and 303; the shapes 303 and 304; and the shapes 304 and 305 are all pitch constrained. Therefore, the two shapes of each pair must be sent to two different masks 310 and 315. Accordingly, the shapes 301 and 303 are sent to a first mask 310. That is, the shapes 301 and 303 are printed during a first exposure in order to produce contours 320. Similarly, the shapes 302, 304, and 305 are sent to a second mask 315. That is, the shapes 302, 304, and 305 are printed during a second exposure in order to produce contours 325. The resulting union of the contours 320 and 325 generates pattern 330 that is sufficient to approximately reproduce the original design layout 300. FIG. 3B illustrates a decomposition of a pattern 340 defined in a layer of design layout for fabricating an IC into two sets of polygons 350 and 360. Each such decomposed set of polygons 350 and 360 is printed during an exposure of a multiple exposure photolithographic printing process. For instance, polygon set 350 is printed during a first exposure in order to produce contours 370 and polygon set 360 is printed during a second exposure in order to produce contours 380. The resulting union of the contours 370 and 380 generates pattern 390 that is sufficient to approximately reproduce the original pattern 340. Accordingly, a valid decomposition solution is such that the union of the contours created/printed from each exposure closely approximates specifications within the original design layout and satisfies multi-exposure photolithographic printing constraints (e.g., the band limit and the target layout specified within the design layout) with no resulting “opens”, “shorts”, or other printing errors materializing on the physical wafer. To use DPL technology, the layout designers need to follow a set of design rules or constraints while designing the layout such that the shapes on a single design layer can be successfully fabricated using two different masks. Some available EDA tools assign two colors (e.g., red and green) to the shapes to identify the two masks with which the shapes will be fabricated. Each shape on a design layer begins with its color unassigned. The EDA tool assigns one of the two colors to each shape on the layer. Shapes that have been assigned to the same color must be spaced apart by at least a certain minimum distance specified by the design rules. Typically, the required minimum spacing between shapes assigned to the same color is greater than the required minimum spacing between two shapes with different colors because shapes with different colors are fabricated using different masks, bypassing the limitations of the single-exposure photolithographic process. In this application, the required minimum spacing between shapes assigned to the same color is referred to as a minimum same color spacing. The required minimum spacing between two shapes with different colors is referred to as a minimum spacing. Since a pitch specifies the sum of the width of a shape (i.e., feature) and the space on one side of the shape separating that feature from a neighboring shape, a minimum same color spacing is pitch minus the width of the shape in some embodiments. A specific color that is assigned to a particular shape is arbitrary. However, the assignment makes sure that the shapes adjacent to the particular shape that are spaced apart from the particular shape by less than the minimum same color spacing have different colors. Some EDA tools model each shape in a design layout as a node in a graph. Two nodes are connected when the corresponding shapes are apart from each other at a distance smaller than the minimum same color spacing. After this modeling process, the layout is represented as clusters of graphs in which nodes are connected. Each node in a graph is assigned a color in such a way to make sure that the neighboring nodes have different colors. This is because when the neighboring nodes (e.g., a connected pair of nodes) have the same color, the corresponding shapes would violate a design rule that requires two shapes with the same color are apart from each other at a distance greater than or equal to the minimum same color spacing. However, when the nodes in a graph form a loop and there are an odd number of nodes in such graph, it is not possible to assign different colors to all pairs of nodes of the graph. FIG. 4 illustrates a graph 405 that has three nodes that form such a loop. The graph 405 represents shapes 1-3 in a layer of a design layout 400. This figure illustrates three different color assignments 401-403 to show that it is not possible to assign different colors to adjacent nodes in a graph that has an odd number of nodes forming a loop. Nodes 1-3 of the graph 405 represent the shapes 1-3, respectively. Two different colors, a first color and a second color, are assigned to the shapes 1-3. The first color is depicted as gray and the second color is white in this example. This figure also illustrates a minimum same color spacing 410 depicted as a horizontal line with two ends having vertical bars. As shown, shape 3 is depicted as three connected rectangles. These three rectangles are connected by design and treated as one shape. The shapes depicted in the figures of this application shown as multiple connected rectangles are treated as one shape. The shapes 1 and 2 are violating the pitch requirement. That is, the two shapes are apart from each other at a distance smaller than the minimum same color spacing 410. So are the shapes 2 and 3. So are the shapes 3 and 1 because the bottom portion of shape 3 is apart from the shape 2 at a distance smaller than the minimum same color spacing 410. Accordingly, the nodes 1-3 of the graph 405 are connected to each other, resulting in a loop. The three different colors assignments 401-403 show the three possible ways of assigning two different colors to the nodes 1-3 and the corresponding shapes 1-3. As shown, no matter how the color assignment is done, one pair of neighboring nodes has the same color. That is, there is always going to be a pair of shapes that would be violating the design rule. FIG. 5 illustrates an example printing error that is materialized on the physical wafer when the three shapes 1-3 illustrated in FIG. 4 are sent to two different masks. Specifically, this figure shows a possible pattern 530 resulting from applying the color assignment 402 described above. As shown, the shapes 1-3 are divided into two sets of shapes 510 and 515 according to the color assignment 402. That is, the shape 2 is sent to the first of the two masks and the shapes 1 and 3 are sent to the second mask. Each set of shapes is printed during an exposure of a double exposure photolithographic printing process (e.g., a DPL process). That is, the shape set 510 (i.e., the shape 2) is printed during the first exposure in order to produce contours 520 and the shape set 515 is printed during the second exposure in order to produce contours 525. However, because the shape 1 and the shape 3 were too close (e.g., within the minimum same color spacing 410) in the pattern 505, the contour for the shape 1 and the contour for shape 2 intersect in this example, resulting in a short. The resulting union of the contours 520 and 525 generates the pattern 530. As shown, the pattern 530 did not meet the specifications within the original design layout represented by the pattern 505 in which shapes 1 and 3 are not meant to connect to each other. Using DPL techniques creates a new challenge for the layout designers because the designers have to satisfy the requirements of DPL techniques in addition to Design Rule Checking (DRC) and Design For Manufacturability (DFM) requirements. Moreover, fixing a double patterning (DP) loop violation is much more complex than fixing a DRC violation. This is because a DRC violation is usually a violation caused by a single shape or interaction of a few shapes whereas a DP loop violation is a set of spacing constraint violations between three or more shapes. It is also relatively more difficult to figure out whether moving a shape to fix a DP loop violation results in a new DP loop violation. There are several existing approaches that address DP loop violations. One of the approaches is editing layouts manually. This approach is time and manpower intensive because the designers have to go through several iterations of edits to figure out the problems and fix them. Thus, this approach has to rely on skills of the designers in finding a solution to a DP loop violation, which is not as straightforward as finding a solution for a DRC violation. Another of the existing approaches is an automatic Rip and Reroute technique. The Rip and Reroute technique rips the shapes and reroutes the shapes to resolve a design rule violation. The Rip and Reroute technique uses a minimum same color spacing as a spacing constraint. That is, this technique separates the shapes in a design layout such that all shapes are apart from one another at a distance greater than or equal to a minimum same color spacing. Using this technique therefore results in separating two shapes that have different colors at a distance that is greater than a distance at which shapes with different colors should be apart from each other. Some Rip and Reroute techniques may be track-based. When the technique is track-based, the technique assigns different colors to predefined tracks. Thus, track-based Rip and Reroute technique may not fully utilize all available space in the design layout because the shapes may not occupy all available track spaces. In addition, the Rip and Reroute technique is computation-intensive and slow because the shapes have to be ripped and rerouted. Also, this technique is of limited use for full custom layouts because the technique modifies existing routing topology to fix a design violation. Finally, the technique also requires connectivity information in the layout. Some embodiments of the invention provide a method for automatically generating and prioritizing several design solutions that resolve a double patterning (DP) loop violation in an IC design layout. The method of some embodiments receives a DP loop violation marker and identifies pairs of edges of shapes that form a double patterning loop based on the DP loop violation marker. For each pair of edges that violates the design rule, the method generates one or more design solutions. Each design solution moves a single edge or both edges to resolve the violation. Some design solutions may introduce new design rule violations. However, a goal of some embodiments is to find a design solution with the least chance of introducing new design rule violations. The method of some embodiments computes the cost of applying each design solution to the IC design layout and prioritizes the generated solutions for all the identified pairs of edges based on the computed cost for each solution. The method in some embodiments then selects a solution from the prioritized solutions and applies the selected solution to the design layout to resolve the double patterning loop violation in the design layout. As described above, the method of some embodiments identifies pairs of violating edges based on a DP loop violation marker. A DP loop violation marker defines a loop formed by the violating shapes in the IC design layout. A DP loop violation marker can be rendered as a geometric shape (e.g., a rectangle, etc.) in the IC design layout. A DP loop violation marker in some embodiments has several child markers, which also can be rendered as geometric shapes in the IC design layout. Each child marker of the DP loop violation marker indicates that two shapes adjacent to the child marker are spaced at a distance smaller than a minimum same color spacing specified by a design rule. In some embodiments, a spacing violation between two shapes is represented by a child marker positioned between the violating shapes. One edge (the violating edge) of each violating shape abuts the child marker. A design solution for the particular pair of violating shapes involves moving at least one of the two edges abutting the child marker such that the shapes no longer violate the design rule. In some cases, one or two marker-adjacent edges are moved perpendicular to one another to increase the spacing between the shapes. In other cases, one or two marker-adjacent edges are moved away from one another in a parallel direction to increase the spacing between the shapes. In yet other cases, a design solution requires both perpendicular and parallel movement of one or more of the shapes. To move edges, some embodiments move the shapes that have edges requiring movement. Some embodiments trim or enlarge shapes to move an edge. The method of some embodiments generates several design solutions for each pair of edges that violates a design rule. For each design solution generated for a DP loop violation, the method of some embodiments computes a cost of applying the solution to the IC design layout. The method of some embodiments bases this cost on the number of shapes found within a certain threshold distance from each moved shape. This accounts for the number of potential new design rule violations introduced by moving the shape. The method also considers distances required for each shape to be moved. The method of some embodiments adjusts the computed cost based on the type of the shape found, the type of the shape to be moved, the distance at which the found shape is spaced from the moved shape, and other factors. To prepare a design solution for cost analysis, the method of some embodiments defines a set of regions based on the new location of each moved shape in the design solution. These regions include an overlapping region, a minimum spacing region, and a minimum same color spacing region (also referred to as same color checking region). The overlapping region is the region the shape will occupy after it is moved according to the design solution. The minimum spacing region is the region outside the overlapping region and within the minimum spacing distance from the overlapping region. The minimum same color spacing region is the region outside the minimum spacing region and within the minimum same color spacing distance from the overlapping region. The method of some embodiments uses the set of defined regions for a design solution to estimate the cost of implementing the design solution. In some embodiments, the method runs a query on each defined region in the set to find the shapes that fall in the defined regions. The method of some embodiments counts the number of shapes that fall in each region and computes costs for each region based on the numbers. When calculating costs for a defined region, the method of some embodiments does not count the shape being moved or any shape whose cost has already been computed for another defined region. The method of some embodiments then performs local color checking operations to maintain the integrity of shape color assignments, which may change when shapes are moved. As described above, each shape on a single layer of an IC design layout may be assigned to one of two different colors (e.g., red and green) to indicate that the shape is to be fabricated on one of the two lithography masks on which the shapes on the layer will be fabricated. When a moved shape does not overlap with another shape after it is moved, the method of some embodiments removes the color assignment of the moved shape. Otherwise, the shape retains its assigned color. In some embodiments, the method discounts the calculated cost of a design solution for amenable shapes found within the set of defined regions. The method of some embodiments finds all shapes falling outside the minimum spacing region and within the minimum same color spacing region. When the shapes found in the region have a uniform color and the moved shape has an assigned color that is different than the uniform color, the method discounts the cost of the shapes found in the minimum same color spacing region. The cost of the shapes is discounted because, while the shapes are within the same color spacing region, they do not introduce a design rule violation (or otherwise impair the movement of the shape in the direction specified by the design solution) since the shapes have a different color and are thus not subject to the same color spacing design rule. When the shapes found in the region have a uniform color but the moved shape has an assigned color that is the same as the uniform color, the discount is not applied. In some embodiments, when the shapes found in the region do not have a uniform color, the method does not apply a discount. When no color is assigned to the moved shape and the shapes found in the minimum same color spacing region have a uniform color, the method of some embodiments discounts the cost of the shapes found in the minimum same color spacing region and assigns the moved shape to the alternate color of the uniform color. When no color is assigned to the moved shape and the shapes found in the minimum same color spacing region have non-uniform colors, the method does not discount the cost of the shapes found in the minimum same color spacing region. Since moving contacts and vias has the potential to introduce design rule violations on two layers, the method of some embodiments adds an additional cost for design solutions requiring movement of contact or via shapes. This additional cost for moving a contact or via shape is configurable. In some cases, a shape that requires moving is not a contact or via, but encloses a contact or via such that the contact or via completely overlaps the shape. A via with such an enclosure may be subject to a minimum enclosure design rule. The method of some embodiments adds an additional cost for a contact or via shape only if, after moving the enclosing shape, the contact or via no longer completely overlaps the enclosing shape or violates the minimum enclosure design rule. That is, the method adds an additional cost for contact and via shapes that the design solution indirectly requires moving due to the movement of an enclosing shape. The method of some embodiments weights the computed costs of a design solution based on the level of difficulty a particular type of shape found in a particular defined region is likely to present in implementing the design solution. A weight could be a multiplication factor applied to the cost calculated for a shape in some embodiments. In other embodiments, weights are scalar values assigned based on the shape and region type. The method of some embodiments assigns different weights to different shapes found in different regions. For instance, the method assigns the highest weight to an instance shape found in a region. An instance shape is a shape that belongs to a design instance, which is a group of shapes that are laid out in a pre-defined manner and can be reused for different locations of a design layout (e.g., a standard cell, custom cell, memory, hard macro, etc.). The shapes in some design instances are prearranged and immutable. The method of some embodiments assigns a cost of infinity to an instance shape found in the selected region to de-prioritize a design solution involving moving a shape from within a design instance. The method assigns the second highest weight to the shapes that connect (or short circuit) to the moved shape. That is, a shape that falls within the overlapping region or abuts the overlapping region is assigned the second highest weight. The method assigns the third highest weight to the shapes that are found in the minimum spacing region (in violation of the minimum spacing design rule). The method assigns the fourth highest weight to contact or via shapes that are found in a region. That is, an additional weight will be assigned to the contact or via shape when a weight is already assigned to the contact or via shape, for example, by falling in a minimum spacing region. The method assigns the fifth highest weight to any non-special shapes (e.g., shapes that are not contact shapes, via shapes, or instance shapes, etc.) found in a region. The method assigns the sixth highest weight to the shapes found in the minimum same color spacing region (in violation of the minimum same color spacing design rule). The method assigns the seventh highest weight to the non-region-based costs. Non-region-based costs are described further below. The method assigns the eighth highest weight to the cost computed for moving a contact or via shape. In some embodiments, the method computes a total cost for a design solution. The method computes costs for each shape moved by the design solution and sums the computed costs. The resulting cost is the overall cost for the design solution. The method computes the overall cost for each of the generated design solutions and prioritizes the design solutions based on the computed costs. For instance, the method assigns the highest priority to the design solution with the lowest computed cost. The method of some embodiments then selects a design solution to apply to the design layout to resolve the DP loop violation. In some embodiments, the method analyzes each design solution from the highest priority solution to the lowest priority solution until the method finds a design solution that does not cause any new design rule violations when applied to the design layout. In some cases, none of the generated design solutions avoid creating a design rule violation when applied to the design layout. In such cases, the method of some embodiments may resolve the DP loop violation by decomposing shapes, as described below. A DP loop violation may also be resolved using shape decomposition. Some embodiments of the invention provide a method for automatically decomposing a shape of an IC design layout into two or more shapes in order to resolve a DP loop violation involving the shape. In contrast to the method of some embodiments described above, this method does not involve moving an edge of a shape to resolve a DP loop violation. This method decomposes the shape by introducing one or more splicing graphs on the shape. These splicing graphs serve as cuts to be made on the shape. That is, the shape is decomposed based on the splicing graphs. In some cases, a splicing graph is a straight line. In other cases, a splicing graph is a curved line. By decomposing the shape into several shapes and assigning the shapes to alternating masks for the same layer, the method breaks the double patterning loop. That is, no pair of the shape and other shapes that form the loop will be assigned to the same color for a mask after the shape is decomposed. In some embodiments, the method introduces splicing graphs to more than one shape of the loop-forming shapes when necessary. Some embodiments minimize the number of splicing graphs introduced to the shape(s). Instead of or in conjunction with receiving a DP loop violation marker, the method of some embodiments performs design rule-checking on a region of a design layout to identify a DP loop violation in the region. When a DP loop violation is identified, the method of some embodiments selects one DP loop and identifies the group of associated shapes for the DP loop. In some embodiments, two shapes in the region are deemed directly associated when the two shapes are within a minimum pitch requirement (e.g., when the two shapes are spaced apart at a distance smaller than a minimum same color spacing). Two shapes are deemed indirectly associated when the first of the two shapes is directly associated with a third shape that is directly associated with the second of the two shapes. Two shapes are also deemed associated when the first of the two shapes is directly or indirectly associated with a third shape that is directly or indirectly associated with the second of the two shapes. Some embodiments use a shape graph to identify the group of associated shapes. The shape graph of some embodiments represents the relationships between the shapes of the design layout region. For instance, the shapes are represented as nodes of the shape graph and the nodes for any two shapes that are directly associated are connected by a link between them. Similarly, the nodes for indirectly associated shapes are indirectly connected through several links and nodes in the shape graph. Thus, all shapes of the group are directly or indirectly connected. The method of some embodiments also identifies locations on all shapes in the identified group to place splicing graphs in the shapes. Some embodiments identify the locations based on one or more design constraints (e.g., a minimum pitch, or width plus minimum same color spacing, between portions of the shapes). For instance, some embodiments identify portions that are too close to each other to be printed in the same exposure (called “critical portions”). Some embodiments also identify the associations between these portions (e.g., identifying pairs of portions that are “adjacent” to each other and thus need to be printed in different exposures). The method of some embodiments identifies a dividing line between such portions as a splicing graph location. Some embodiments define a set of segment graphs that represent each critical portion as a node or vertex of a segment graph, and each association between critical portions as a link in the graph. The method utilizes the set of segment graphs when assigning a color to each segment as will be described below. Some embodiments define a set of segment graphs before creating shape graphs and use the set of segment graphs to create the shape graphs. For instance, two shapes are deemed connected in a shape graph if a portion of one shape is in the same segment graph as a portion of the other shape. The method of some embodiments uses a shape graph and a set of segment graphs for the segments (i.e., critical portions) that belong to the shapes represented in the shape graph in order to assign colors to the shapes in the group of associated shapes represented by the shape graph. Using these graphs, the method introduces one or more splicing graphs to one or more shapes in the group in such a way that minimizes the number of splicing graphs introduced. For instance, the method selects an initial node to select an initial shape and then assigns a color to the initial shape. The method of some embodiments selects a node in the shape graph that is connected to only one other node as the initial node. When there is no such node in the shape graph, the method selects a shape in the group that has the next fewest number of critical portions compared to the initial shape. The method assigns a color to the initial shape by assigning a color to each critical portion of the initial shape. In some embodiments, the method assigns the same color to all critical portions of the initial shape. When assigning a color to a critical portion, the method of some embodiments also colors all other critical portions that share the same segment graph with the critical portion of the initial shape that has just been colored. The method alternates the colors assigned to the critical portions sharing the same segment graph such that no two critical portions represented by a pair of connected nodes of the shared segment graph are assigned the same color. When the method finishes assigning colors to all critical portions of the initial shape and all critical portions that share the same segment graphs with the critical portions of the initial shape, the method selects a next shape in the group for color assignment. The method selects the next shape based on certain criteria. In some embodiments, the criteria include (1) whether a shape includes a splicing graph (i.e., whether the shape has two or more critical portions assigned to different colors), (2) whether the shape is partially colored (i.e., whether the shape has at least one colored critical portion but not all critical portions are colored), (3) a number of critical portions that the shape has, etc. For instance, the method selects shapes that have no splicing graphs over shapes that have splicing graphs. The method selects shapes that are partially colored over shapes that are not colored. The method selects shapes with fewer critical portions over shapes with more critical portions. When two or more shapes are selected based on these criteria, the method of some embodiments uses a non-tying criterion (e.g., random selection) to select the next shape to color. The method then colors the next shape in a similar manner to that which the method colored the initial shape. That is, the method assigns the same color to all critical portions of the shape and assigns alternate colors to all other critical portions that share the same segment graph with the critical portions of the shape being colored. When some of the critical portions of the shape are already colored, the method assigns the color that is assigned to the majority of the colored critical portions to all critical portions that have not been assigned colors. The method repeats the selection and coloring operations until all critical portions of all shapes in the group are assigned colors. The method will introduce one or more splicing graphs to one or more of the shapes in the group. One of the shapes with a splicing graph is a loop-forming shape. In this manner, the method resolves the DP loop violation by introducing one or more splicing graphs to break the DP loop. In some embodiments, when the number of splicing graphs introduced to the shapes in the group is not one, the method goes back to the point when it made a random choice in selecting a shape to assign color(s) (e.g., by undoing color assignments made after that point) and selects another shape for color assignment. As described above, some embodiments consider all shapes in the group of associated shapes to resolve a DP loop violation. That is, these embodiments consider the loop-forming shapes as well as other shapes that are directly and indirectly associated with the loop-forming shapes. However, other embodiments consider only the loop-forming shapes to resolve the DP loop violation. That is, the method of some embodiments performs the selecting and coloring operations that are described above only on the loop-forming shapes to resolve the violation that these loop-forming shapes commit and assigns colors to the rest of the shapes in the group or design layout region. In some cases, some DP loop violations may not be resolved by introducing splicing graphs in the shape(s) in the group of associated shapes. In such cases, the method of some embodiments attempts to resolve such DP loop violations by moving one or more edges of the shapes as described above. In some embodiments, the method determines that a DP loop violation may not be resolved by introducing splicing graphs when two critical portions of one shape are within a pitch requirement from each other (e.g., the two critical portions of the shape are spaced apart from each other at a distance smaller than a minimum same color spacing). The preceding Summary is intended to serve as a brief introduction to some embodiments of the invention. It is not meant to be an introduction or overview of all inventive subject matter disclosed in this document. The Detailed Description that follows and the Drawings that are referred to in the Detailed Description will further describe the embodiments described in the Summary as well as other embodiments. Accordingly, to understand all the embodiments described by this document, a full review of the Summary, Detailed Description and the Drawings is needed. Moreover, the claimed subject matters are not to be limited by the illustrative details in the Summary, Detailed Description and the Drawing, but rather are to be defined by the appended claims, because the claimed subject matters can be embodied in other specific forms without departing from the spirit of the subject matters. In the following detailed description of the invention, numerous details, examples, and embodiments of the invention are set forth and described. However, it will be clear and apparent to one skilled in the art that the invention is not limited to the embodiments set forth and that the invention may be practiced without some of the specific details and examples discussed. Some embodiments of the invention provide a method for automatically generating and prioritizing several design solutions that resolve a double patterning (DP) loop violation in an IC design layout. The method of some embodiments receives a DP loop violation marker and identifies pairs of edges of shapes that form a double patterning loop based on the DP loop violation marker. For each pair of edges that violates the design rule, the method generates one or more design solutions. Each design solution moves a single edge or both edges to resolve the violation. Some design solutions may introduce new design rule violations. However, a goal of some embodiments is to find a design solution that does not introduce new design rule violations. The method of some embodiments computes the cost of applying each design solution to the IC design layout and prioritizes the generated solutions for all the identified pairs of edges based on the computed cost for each solution. The method in some embodiments then selects a solution from the prioritized solutions and applies the selected solution to the design layout to resolve the double patterning loop violation in the design layout. A DP loop violation marker contains information regarding a DP loop violation in a design layout. In some embodiments, the information contained in the marker includes the coordinates of vertexes of a geometric shape that represents the marker in the design layout, the identifiers that identify the shapes that are forming the loop, the colors assigned to the violating shapes, the coordinates of the edges of the violating shapes, etc. A DP loop violation marker is represented as a geometric shape (e.g., a rectangular shape) in the design layout. The geometric shape representing the marker will share edges with the violating shapes in some embodiments. Throughout this application, a “marker” refers to the geometric shape that represents the marker as well as the data that contain the information regarding the violation, for simplicity of discussion. A DP loop violation can be resolved by breaking the loop with an odd number of nodes. The loop breaks when one of the shapes, which is represented by a node in the graph, is moved such that the shape is apart from one of its neighbors at a distance greater than the minimum same color spacing. FIG. 6 illustrates an example of breaking a DP loop formed by an odd number of nodes in a graph by moving one of the corresponding shapes from a neighboring shape. Specifically, this figure illustrates in two different stages 601 and 602 that a loop formed by the nodes 1-3 of the graph 405 is getting broken by moving shape 3 of the design layout 400 from shape 1. The design layout 400 and the graph 405 are described above by reference to FIG. 4. In the first stage 601, the shapes 1-3 are apart from one another at a distance smaller than the minimum same color spacing 410. The shapes 1 and 3 are assigned to the same color and thus violating the design rule that imposes the minimum same color spacing 410 on any pair of neighboring shapes in the design layout 400. In the second stage 602, the loop formed by the nodes 1-3 is broken by moving the shape 3 to the right such that the shape 3 is apart from the shape 1 at a distance greater than the minimum same color spacing 400. To move edges, some embodiments move the shapes that have the moving edges. Some embodiments trim or enlarge shapes as the edge(s) of the shapes are moved. For instance, the horizontal rectangle of shape 3 is elongated to facilitate the movement of the upper vertical rectangle to the right. Now the shapes 1 and 2 are apart from each other at a distance smaller than the minimum same color spacing, but these two shapes are not violating the design rule as long as different colors are assigned to these two shapes. The shapes 2 and 3 are not violating the design rule for the same reason. The shapes 3 and 1 are no longer violating the design rule because these two shapes are now further apart from each other at a distance that the design rule does not require to have different colors. FIG. 7 conceptually illustrates a design solutions generator 700 of some embodiments. Specifically, the figure illustrates an example of generating and prioritizing design solutions that resolve a DP loop violation. The design solutions generator 700 retrieves a DP loop violation marker and a design layout and generates design solutions based on the DP loop violation marker. The design solutions generator 700 also prioritizes the generated design solution based on certain criteria. This figure illustrates design layouts 705, DP loop violation markers 710, the design solutions generator 700, design rules 735, and design solutions 740. The design solutions generator 700 includes a marker analyzer 715, a loop edge pair identifier 720, a solutions generator 725, and a solutions prioritizer 730. This figure also illustrates a design layout 745, a DP loop violation marker 750, and three child markers 751, 752, and 753. The design layout 745 includes three shapes 746, 747, and 748 among other shapes (not shown). The design layouts repository 705 stores design layouts. The design layouts repository 705 in some embodiments receives the design layouts from design software applications, which design engineers use to generate the design layouts. In some embodiments, the design layouts stored in the design layouts repository 705 are in a database file format, e.g., GDS II stream format (GDSII). The DP loop violation marker repository 710 stores DP loop violation markers. The DP loop violation marker repository 710 in some embodiments receives markers from design software applications, which generate markers by checking the shapes in a design layout against a design rule that requires two shapes having the same color are not closer to each other than a threshold distance. By separating marker generation from design solution generation, some embodiments allow the design solutions generator 700 to be independent of the software applications that generate markers. The marker analyzer 715 analyzes DP loop violation markers for DP loop violations in a design layout. The marker analyzer 715 retrieves a DP loop violation marker from the DP loop markers repository 710. The marker analyzer 715 identifies the necessary information for generating design solutions from a DP loop violation marker. For instance, the marker analyzer 715 identifies the design rule that is violated, the design layout that includes the set of shapes that violate the rule, the coordinates of the marker to render the marker as a geometric shape, etc. The marker analyzer 715 sends the identified information to other modules of the design solutions generator 700. For instance, the marker analyzer 715 sends the marker and the identification of the design layout 745 to the loop edge pair identifier 720. The shapes 746, 747, and 748 are only a region of a layout of the design layout 745. Other shapes are not depicted for simplicity. In some embodiments, the marker analyzer 715 generates a set of child markers based on a DP loop violation marker. Like a DP loop violation marker, a child marker is also data that contains information and can be rendered as a geometric shape in the design layout. A child marker specifically identifies a pair of edges—one edge from one of two violating shapes and the other edge from the other of the two violating shapes. The identified edges are apart from each other at a distance that is smaller than a distance at which two shapes with the same color should be apart from each other (e.g., a minimum same color spacing). The geometric shape representing a child marker would be placed in between the identified edges of two violating shapes. For each pair of violating shapes, the marker analyzer 715 generates a child marker. For instance, the marker analyzer 715 generates three child markers 751, 752, and 753 for the three pairs of violating shapes of the design layout 745 as shown. The child markers are depicted as rectangles with two diagonal lines inside the rectangles in this figure. In some embodiments, the marker analyzer 715 may retrieve child markers along with a DP loop violation marker that is a parent marker of the child markers. That is, in these embodiments, the marker analyzer 715 uses the child markers generated by software applications that generate DP loop violation markers. The loop edge pair identifier 720 identifies all pairs of edges of the violating shapes that form a loop. The loop edge pair identifier 720 identifies the pairs of edges based on the DP loop violation marker and the child markers received from the marker analyzer 715. The loop edge pair identifier 720 sends the information about the identified pairs of edges to the design solutions generator 725. For instance, the loop edge pair identifier 720 identifies three pairs of edges (pairs 1-3). For pair 1, the loop edge pair identifier 720 identifies the right edge of the shape 747 and the left edge of the shape 748. For pair 2, the loop edge pair identifier 720 identifies the edge of the shape 746 that faces the child marker 751 as shown. For pair 3, the loop edge pair identifier 720 identifies the edge of the shape 746 that faces the child marker 752 and the left side of 748. The solutions generator 725 generates a set of design solutions for each of the edge pairs 1-3 that the loop edge pair identifier has identified. A design solution that the solutions generator 725 generates for a pair of edges requires moving one or both edges of the pair in order to break the loop formed by the violating shapes. More specifically, a design solution requires that the distance between the two pairs of edges to be greater than or equal to the minimum same color spacing. For instance, the solutions generator 725 generates N solutions (with N being an integer) that include solutions 1-3 shown in FIG. 7. For simplicity, only solutions 1-3 of the N solutions are shown in this figure. Each of the N solutions specifies a set of edge movements to break a DP loop formed by the three shapes 746-748 of the design layout 745. For instance, each of solutions 1-3 involves changing a distance between the shapes that includes pair 1 (i.e., the shapes 747 and 748). The solution 1 requires moving the shape 748 to the right such that the distance between the shape 748 and the shape 747 is greater than a minimum same color spacing. The solution 2 requires moving the shape 747 to the left. The solution 3 requires moving both of the shapes 747 and 748 away from each other. The solutions prioritizer 730 prioritizes the design solutions generated by the solutions generator 725 based on the costs of applying the design solutions. For instance, the solutions prioritizer 730 in some embodiments computes a cost of applying each generated design solution to the design layout and prioritizes the design solutions in the order of the lowest cost to the highest cost. For each design solution generated for a DP loop violation, the solutions prioritizer 730 in some embodiments computes a cost of applying the solution to the IC design layout. The solutions prioritizer computes the cost for applying the solution based on a number of shapes that are found within a certain threshold distance from each moved shape. The solutions prioritizer accounts for the number of shapes that overlaps with the moved shape(s) in computing the cost. The solutions prioritizer also considers distances required for each shape to be moved. The solutions prioritizer of some embodiments adjusts the computed cost based on the type of a shape found, the distance at which the found shape is from the moved shape, the type of the moved shape, etc. More details of computing costs for applying a design solution to the design layout will be described further below in Section II. To check whether applying a generated design solution causes a new violation, the solutions prioritizer 730 retrieves other design rules from the design rules repository 735. The solutions prioritizer 730 verifies the new locations of the shapes against each design rule. When applying a design solution results in a new design rule violation, the solutions prioritizer 730 assigns an additional cost to the design solution. For instance, the solution 2 shown in FIG. 7 resolves the DP loop violation by requiring to move the shape 747 to the left. However, the shape 747 is then too close to the shape 746. That is, the shapes 746 and 747 would be apart at a distance smaller than a distance that a design rule requires two shapes to be apart from each other regardless of the colors that these two shapes have. Thus, assuming that the cost of applying a design solution is otherwise the same for the three solutions 1-3, the solutions prioritizer 730 prioritizes solution 2 lower than the solutions 1 and 3, which do not cause a new design rule violation when applied. The solutions prioritizer 730 stores the prioritized design solutions along with priority information in the design solutions repository 740. An example operation of the design solutions generator 700 will now be described by reference to FIG. 8. FIG. 8 conceptually illustrates a process 800 performed by some embodiments to generate and prioritize design solutions and to apply one of the design solutions to resolve a DP loop violation. In some embodiments, the process is performed by the design solutions generator 700. As shown in FIG. 8, process 800 begins by retrieving (at 805) a DP loop violation marker from a repository that stores DP loop violation markers. FIG. 7 illustrates that the marker analyzer 715 retrieves the DP loop violation marker 750 from the DP pattern loop markers repository 710. The marker analyzer 715 parses the retrieved marker 750 and identifies the design layout 745 using the information contained in the marker 750. The information in the marker 750 also indicates that the three shapes 746, 747, and 748 are forming a DP loop and thereby violating a design rule that requires the same colored shapes to be apart from each other at a distance greater than a minimum same color spacing. Next, process 800 generates (at 810) design solutions based on the DP loop violation marker the process retrieved at 805. In the example of FIG. 7, the marker analyzer 715 generates the child markers 751, 752, and 753 depicted in this figure next to the lower encircled number 2 based on the information contained in the DP loop violation marker 750. The child marker 751 is placed between the shape 746 and 747 to indicate that these two shapes are apart at a distance smaller than a minimum same color spacing. The marker analyzer 715 places the child marker 752 between the shapes 746 and 748. The marker analyzer 715 places the child marker 753 between the shapes 747 and 748. The loop edge pair identifier 720 then receives the DP loop marker 750 and the child markers 751-753 from the marker analyzer 715. Based on the received markers, the loop edge pair identifier 720 identifies three pairs of shapes that include three pairs of edges (pairs 1-3). A first identified shape pair includes the shapes 747 and 748 which includes edge pair 1. A second identified shape pair includes the shapes 746 and 747 which includes edge pair 2. A third identified shape pair includes the shapes 746 and 748 which includes edge pair 3 as shown in this figure by the lower encircled number 3. The solutions generator 725 generates N design solutions for breaking the DP loop formed by the three shapes 746-748 where N is the total number of design solutions generated for the DP loop violation. The solutions generator 725 generates a set of design solutions for each of the identified pairs of shapes. In this example, the set of design solutions that the solutions generator 725 generated for the shapes 746 and 748 includes the solutions 1-3. The solution 1 requires moving the shape 748 to the right such that the distance between the edges of the shape 748 and the shape 746 facing the child marker 752 is greater than the minimum same color spacing. The solution 2 requires moving the shape 747 to the left such that the two edges facing the child marker 753 is greater than the minimum same color spacing. The solution 3 requires moving both of the shapes 747 and 748 away from each other. There may be more solutions that require one or both of these two shapes to move, which are not depicted in this figure. For each of the remaining two pairs of shapes, the solutions generator 725 generates design solutions. These additional solutions and the solutions 1-3 make up the N design solutions that the solutions generator 725 generates in this example. Back to FIG. 8, process 800 then prioritizes (at 815) the design solutions that the process has generated at 810. FIG. 7 illustrates that the solutions prioritizer 730 computes the cost of applying each of the N design solutions. In the example of FIG. 7, applying any of the solutions 1-3 does not result in any other shapes falling within a threshold distance (e.g., a minimum same color spacing) nor a new DP loop violation other than the DP loop violation that the design solution resolves. However, applying the solution 3 results in a new design violation as described above. Accordingly, the solutions prioritizer 730 prioritizes the solution 2 lower than the solutions 1 and 3. The solutions prioritizer 730 prioritizes all N solutions, placing solution M at the bottom of the prioritized solutions because solution M has the highest cost of applying in this example. Next, process 800 applies (at 820) a generated design solution to the design layout. That is, the process moves one or more of the violating shapes in the design layout in order to break the DP loop formed by the violating shapes. In some embodiments, a design modifier module (not shown) of the design solutions generator 700 applies the design solution. In other embodiments, a separate device or software application different than the design solutions generator 700 applies the design solution to the design layout. Moreover, different embodiments select the design solution to apply to the design layout differently. For instance, the design modifier module or the separate device/software application may automatically select a design solution with the highest priority (e.g., a design solution with the lowest applying cost) in some embodiments. In other embodiments, a designer using a design software application may select a design solution from the prioritized design solutions. Process 800 then ends. One of ordinary skill in the art will recognize that process 800 is a conceptual representation of the operations used to generate design solutions based on a received DP loop violation marker and to apply a generated design solution in order to resolve the DP loop violation caused by the shapes in the design layout. The specific operations of process 800 may not be performed in the exact order shown and described. The specific operations may need not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. For instance, in some embodiments, process 800 is performed by one or more design software applications that execute on one or more computers. Specifically, receiving a marker at 805 and generating design solutions at 810 may be performed by one design software application running on one computer and selecting and applying a generated design solution may be performed by another design software application running on the same or different computer. It is to be noted that rendering of the markers (violation markers as well as child markers) is not required. The rendering of these markers visually aids the users of the design solutions to recognize the violations. The design solutions generator 700 can generate and prioritize design solutions without rendering the markers to display. Also, the markers do not have to be in the forms that they are depicted as in the figures. Any geometric shapes will suffice. Several more detailed embodiments of the design solutions generator are described in Section II below. Some embodiments of the invention provide a method for automatically decomposing a shape of an IC design layout into two or more shapes in order to resolve a DP loop violation in which the shape is involved. In contrast to the method of some embodiments described in subsection I.A., this method does not involve moving an edge of a shape to resolve a DP loop violation. This method decomposes the shape by introducing one or more splicing graphs on the shape. These splicing graphs serve as the cuts to be made on the shape. That is, the shape is decomposed based on the splicing graphs. In some cases, a splicing graph is a straight line. In other cases, a splicing graph is a curved line. By decomposing the shape into several shapes, the method breaks the double patterning loop. That is, no pair of the shape and other shapes that were forming the loop will be assigned the same color for a mask after the shape is decomposed. In some embodiments, the method introduces splicing graphs to more than one shape of the loop-forming shapes when necessary. Some embodiments minimize the number of splicing graphs to introduce to the shape(s). FIG. 9 conceptually illustrates a design decomposer 900 of some embodiments that resolves a DP loop violation by decomposing one of the shapes that form a DP loop. Specifically, the figure illustrates that the design decomposer 900 breaks a DP loop formed by shapes 946, 947, and 948 in a design layout 945 by decomposing the shape 946. By decomposing the shape 946, the design decomposer 900 can assign two different colors to the shape 946 so that the three shapes 946, 947, and 948 no longer forms a DP loop. In contrast to the design solutions generator 700 described above by reference to FIG. 7, the design decomposer 900 in some embodiments performs design rule-checking on a region of design layout to identify a DP loop violation in the region instead of or in conjunction with receiving a DP loop violation marker. This figure illustrates a design layouts repository 905 and a design rules repository 935. The design decomposer 900 includes a design rule checker 915, a shape segmentor 920, a splicing graph minimizer 925, and a coloring engine 930. The design layouts repository 905 stores design layouts. The design layouts repository 905 in some embodiments receives the design layouts from design software applications, which design engineers use to generate the design layouts. In some embodiments, the design layouts stored in the design layouts repository 905 are in a database file format, e.g., GDS II stream format (GDSII). The design rules repository 935 stores design rules. The design rules repository 935 in some embodiments receives design rules from design software applications, which generate design rules according to the design engineers' inputs. Design rules impose certain design constraints on the shapes in design layouts. For example, a minimum same color spacing rule (also referred to as minimum pitch requirement) requires that two shapes with the same assigned color be apart from each other at a certain minimum distance. The design rule checker 915 receives or retrieves a design layout from the design layout repository 905 and verifies the design layout against the design rules to see if the shapes in the layout are in violation of the design rules. For instance, the design rule checker 915 receives the design layout 945. The design layout 945 includes the shapes 946, 947, 948, 949, and 950 among other shapes (not shown in FIG. 9 for simplicity of description). As the design rule checker 915 verifies the design layout 945, the design rule checker finds that three shapes 946, 947, and 948 are within the minimum pitch requirement among one another. Therefore, any two of these three shapes have to have different colors in order to meet the minimum pitch requirement. However, no combination of colors will allow these three shapes to meet the minimum pitch requirement and these three shapes form a DP loop. The design rule checker also finds that the shapes 946 and 949 are within the minimum pitch requirement. Each of bidirectional arrows 951-954 is depicted in the figure to indicate that a pair of shapes are within the minimum pitch requirement. For instance, the arrow 952 indicates that the shapes 946 and 949 are within the pitch requirement. In some embodiments, the design rule checker 915 may create and utilize a shape graph (not shown) to find out the relationship between the shapes and any design violations formed by the shapes. Creating and utilizing shape graphs are described further below in Section III. When the design rule checker 915 finds a DP loop violation, the design rule checker 915 notifies the shape segmentor 920. The shape segmentor 920 defines a group of shapes and identifies portions of the shapes in the group that are too close to each other to be printed in the same mask (e.g., too close to have the same assigned color). Such portions are referred to as “critical portions” or “critical shape segments” (CSSs) throughout this application. The group of shapes that the shape segmentor 920 defines include the shapes that form the DP loop and other shapes that are within the minimum pitch requirement from the loop-forming shapes. The shape segmentor 920 further includes in the group shapes that are within the minimum pitch requirement from the shapes in the group. For instance, the shape segmentor 920 puts the shapes 946, 947, and 948 in the group the shape segmentor 920 defines. The shape segmentor 920 also puts the shape 949 in the group because the shape 949 and the shape 946 are within the minimum pitch requirement. However, the shape segmentor 920 will not put the shape 950 in the group because the shape 950 is not within the pitch requirement from any of the four shapes 946-949. Once the shape segmentor 920 defines the group of shapes, the shape segmentor 920 identifies critical portions. As shown, the shape segmentor identifies six critical portions 956-961. FIG. 9 also illustrates conceptual associations (or “links”) 962-965 between a pair of critical portions to indicate that the two critical portions in the pair are too close to each other to have the same assigned color. The shape segmentor 920 also un-assigns any color that had been assigned to the shapes in the group previously. In some embodiments, the shape segmentor 920 may create and utilize a segment graph (not shown) to find out the relationship between the critical portions. Creating and utilizing segment graphs are described further below in Section III. The splicing graph minimizer 925 introduces splicing graphs in the shapes in the defined group in such a way that minimizes the number of splicing graphs in the shapes in the group. For instance, the splicing graph minimizer selects an initial shape to assign a color first. The splicing graph minimizer of some embodiments selects a shape that has one critical portion. The shapes 949 and 947 are such shapes as shown in FIG. 9. When there is no such shape in the defined group, the splicing graph minimizer selects a shape in the group that has the least number of critical portions as the initial shape. When there are two or more shapes that have one critical portion, the splicing graph minimizer of some embodiments selects on of it based on a non-tying criteria (e.g., random selection). In this example, the splicing graph minimizer selects the shape 949. The splicing graph minimizer assigns a color to the initial shape by assigning a color to each critical portion in the initial shape. In some embodiments, the splicing graph minimizer assigns the same color to all critical portions of the initial shape. The splicing graph minimizer 925 assigns color 1 (e.g., red) to the shape 961 as shown. When assigning a color to a critical portion, the splicing graph minimizer 925 of some embodiments also colors all other critical portions that are associated with the critical portions of the initial shape through the links The critical portions 958, 959, and 960 are such critical portions as shown. The critical portion 958 is associated with the critical portion 961 of the shape 949 through the link 965. The critical portion 959 is associated with the critical portion 961 through links 963 and 965. The critical portion 960 is associated with the critical portion 961 through the links 964, 963, and 965. The splicing graph minimizer 925 alternates the colors to assign to the associated critical portions such that no two neighboring associated critical portions are assigned to the same color. As shown, the splicing graph minimizer 925 assigns color 2 (e.g., green) to the critical portions 958 and 960 and assigns color 1 to the shape 947. As such, no two neighboring critical portions of the associated critical portions 958, 959, 960, and 961 have the same assigned color. When the splicing graph minimizer 925 finishes assigning colors to all critical portions of the initial shape and all critical portions that are associated with the critical portions of the initial shape, the splicing graph minimizer 925 selects a next shape in the group to assign colors. The splicing graph minimizer 925 selects the next shape based on certain criteria. In some embodiments, the criteria include (1) whether a shape includes a splicing graph (i.e., whether the shape has two or more critical portions assigned with different colors already), (2) whether the shape is partially colored (i.e., whether the shape has at least one colored critical portion), (3) a number of critical portions that the shape has, etc. For instance, the splicing graph minimizer 925 selects shapes that have no splicing graphs over shapes that have splicing graphs. The splicing graph minimizer 925 selects shapes that are partially colored over shapes that are not colored. The splicing graph minimizer 925 selects shapes with fewer critical portions over shapes with more critical portions. When two or more shapes are selected based on these criteria, the splicing graph minimizer 925 in some embodiments uses a non-tying criterion (e.g., random selection) to select the next shape to color. As shown, the splicing graph minimizer 925 selects the shape 947 as the next shape to color. However, the shape 947, which itself is the critical portion 959, is already completely colored. Thus, the splicing graph minimizer 925 can then select one of the two remaining shapes 946 and 948. At this point, these two remaining shapes are tied based on the three criteria described above. That is, both of the two shapes are partially colored (at this point, only the critical portion 958 of the shape 946 has been colored and only the critical portion 960 of the shape 948 has been colored); both of the shapes do not include a splicing graph yet (the remaining critical portion of each of these two shapes do not have an assigned color yet); and both have the same number of critical portions (i.e., two). Therefore, the splicing graph minimizer 925 in this example selects the shape 948 randomly. The splicing graph minimizer 925 then assigns colors to the next shape in a similar manner that the splicing graph minimizer 925 assigned colors to the initial shape. That is, the splicing graph minimizer 925 assigns the same color to all critical portions of the next shape and assigns alternate colors to all other critical portions that have links with the critical portions of the shape being colored. When some of the critical portions of the shape are already colored, the splicing graph minimizer 925 assigns the color that is assigned to the majority of the colored critical portions of the shape to all critical portions that have not had assigned colors. Accordingly, the splicing graph minimizer 925 in this example assigns color 2 to the critical portion 957 because color 2 is the color that is assigned to the other critical portion of the shape 948 (i.e., the critical portion 960). The splicing graph minimizer 925 then assigns color 1 to the critical portion 956 of the shape 946 because the critical portion 956 is associated with the critical portion 957, which has color 2 as an assigned color. The splicing graph minimizer 925 repeats this selection and coloring operations until all critical portions of all shapes in the group have assigned colors. One or more splicing graphs will have been introduced to one or more of the shapes in the group. One of the shapes that will have a splicing graph is a loop-forming shape. In this manner, the splicing graph minimizer 925 resolves the DP loop violation by breaking the DP loop. In the example of FIG. 9, all critical portions of all shapes in the group have assigned colors. As shown, the shape 946 have a splicing graph between the critical portions 956 and 958 because these two portions have different colors and have to be sent to different masks. In some embodiments, when the number of splicing graphs to introduce to the shapes in the group is not one, the splicing graph minimizer 925 goes back to the point when it made a random choice in selecting a shape to assign color(s) (e.g., by undoing color assignments made after that point) and selects another shape to assign color(s)). As described above, the splicing graph minimizer 925 considers all shapes in the group of associated shapes to resolve a DP loop violation. That is, the splicing graph minimizer considers the loop-forming shapes (e.g., the shapes 946-948) as well as other shapes (e.g., the shape 949) that are associated with the loop-forming shapes. However, the splicing graph minimizer 925 in other embodiments may consider only the loop-forming shapes to resolve the DP loop violation. That is, the splicing graph minimizer 925 of these embodiments performs the selecting and coloring operations that are described above only on the loop-forming shapes to resolve the violation that these loop-forming shapes are committing and then assigns colors to the rest of the shapes in the group or design layout region. The coloring engine 930 colors the shapes according to the colors assigned to the shapes by the splicing graph minimizer 925. That is, the coloring engine 930 modifies the design layout 945 and deposits the modified design layout in the design layouts repository 905. In some cases, some DP loop violations may not be resolved by introducing splicing graphs in the shape(s) in the group of associated shapes. In such cases, the design decomposer 900 of some embodiments attempts to resolve such DP loop violations by moving one or more edges of the shapes as described above in subsection I.A. In some embodiments, the design decomposer determines that a DP loop violation may not be resolved by introducing splicing graphs when two critical portions of one shape are within a pitch requirement from each other (e.g., the two critical portions of the shape are apart from each other at a distance smaller than a minimum same color spacing). An example operation of the design decomposer 900 will now be described by reference to FIG. 10. FIG. 10 conceptually illustrates a process 1000 performed by some embodiments to find and resolve a DP loop violation by decomposing one or more shapes in a layer of a design layout that includes the DP loop. In some embodiments, the process is performed by the design decomposer 900. The process begins by receiving (at 1005) (i) a region of a design layout layer that includes shapes at specified locations and (ii) design rules for the design layout region. In some embodiments, the design rules include a minimum pitch requirement (e.g., the minimum distance that two shapes can be from each other and still be printed in the same exposure) in some embodiments. As described above, FIG. 9 illustrates a simplified example design layout region 945 that the design decomposer 900 has received. Next, process 1000 performs (at 1010) rule-checking to identify a DP loop violation. The process verifies the design layout against the design rules to see the shapes in the layout are in violation of the design rules. For instance, the design decomposer finds that the shapes 946-948 are within the minimum pitch requirement among one another. Therefore, any two of these three shapes have to have different colors in order to meet the minimum pitch requirement. However, no combination of colors will allow these three shapes to meet the minimum pitch requirement and these three shapes form a DP loop. The process then defines (at 1015) a group of shapes. The group of shapes that the process defines includes the shapes that form the DP loop and other shapes that are within the minimum pitch requirement from the loop-forming shapes. The process further includes in the group those shapes that are within the minimum pitch requirement from the shapes in the group. For instance, the design decomposer 900 puts the shapes 946, 947, and 948 in the group that the shape decomposer 900 is defining. The design decomposer 900 also puts the shape 949 in the group because the shape 949 and the shape 946 are within the minimum pitch requirement. However, the shape decomposer 900 will not put the shape 950 in the group because the shape 950 is not within the pitch requirement from any of the four shapes 946-949. The process then identifies (at 1020) critical portions in the shapes of the defined group. As the process identifies the critical portions, the process also un-assigns any color that had been previously assigned to the shapes in the group. For instance, the shape segmentor 920 identifies six critical portions 956-961. Next, the process optimizes (at 1025) decomposition of shapes in the group in order to resolve the DP loop violation by minimizing the number of splicing graphs to introduce to the shapes in the group. The process in some embodiments assigns colors to the critical portions such that at least one of the loop forming shapes have two critical portions with different colors assigned. The design decomposer 900 assigns color 1 (e.g., red) to the shape 961 as shown in FIG. 9. The design decomposer 900 then assigns color 2 (e.g., green) to the critical portions 958 and 960 and assigns color 1 to the shape 947. As such, no two neighboring critical portions of the associated critical portions 958, 959, 960, and 961 have the same assigned color. The design decomposer 900 then assigns color 2 to the critical portion 957 because color 2 is the color that is assigned to the other critical portion of the shape 948 (i.e., the critical portion 960). The design decomposer 900 then assigns color 1 to the critical portion 956 of the shape 946 because the critical portion 956 is associated with the critical portion 957, which has color 2 as an assigned color. As a result, the shape 946 has a splicing graph between the critical portions 956 and 958 because these two portions have different colors and have to be sent to different masks. Process colors (at 1030) the shapes in the group according to the colors assigned (at 1025) to the shapes. That is, the process modifies the design layout and deposits the modified design layout in a design layouts repository. FIG. 11 conceptually illustrates a process 1100 that some embodiments perform to generate design solutions to a DP loop violation in a design layout. The process 1100 in some embodiments is performed by the design solutions generator 700 described above by reference to FIG. 7. The process in some embodiments starts when a designer using the design solutions generator 700 initiates this process to generate design solutions to fix a DP loop violation in a design layout. The design layout is opened for examining and/or editing in a design software application that the designer is using. The process in some embodiments starts when it detects a new DP violation marker that indicates a DP loop violation is in the design layout. As described above, a DP loop violation marker indicates that some shapes in the design layout are forming a DP loop in which a pair of neighboring shapes in the loop cannot be assigned different colors. Such a loop is referred to as a “DP loop” throughout this application. That is, two shapes of a pair are apart from each other at a distance smaller than a required distance, which is a distance at which a design rule requires two shapes with the same color in the design layout to be apart from each other. Several of such pairs of shapes form a conceptual loop in which a pair of neighboring shapes cannot have different colors assigned. The process 1100 will be described by reference to FIGS. 12 and 13 which illustrate generating design solutions that resolve a DP loop violation. Process 1100 begins by receiving (at 1105) a DP loop violation marker. In some embodiments, the process receives the DP loop violation marker directly from another design software application. In other embodiments, the process may retrieve the DP loop violation marker from a repository that stores DP loop violation markers. Next, process 1100 identifies (at 1110) all pairs of shapes that are forming the DP loop. The process in some embodiments identifies these pairs of shapes based on the information contained in the DP loop violation marker. For each of the identified pairs, the process in some embodiments generates a child marker to place between the two shapes of the pair. The child marker indicates that the two shapes of the pair are apart from each other at a distance smaller than the minimum same color spacing required by the violated design rule. A design solution that resolves the DP loop violation will require moving one or both of the two shapes such that the distance between the two shapes is greater than or equal to the minimum same color spacing. FIG. 12 illustrates in four different stages 1201-1204 an example of a DP loop violation committed by several shapes in a design layout 1200 and several solutions generated by a design solutions generator (not shown) of some embodiments to resolve the DP loop violation. This figure illustrates the design layout 1200 that includes shapes 1205, 1210, and 1215 among other shapes which are not illustrated in this figure for simplicity. This figure also illustrates a DP loop marker 1220 and three child markers 1221-1223. The shape 1210 has edges 1211 and 1212. The edge 1211 is the top edge of the shape 1210. The edge 1212 is the right edge of the shape 1211. The shape 1215 has edges 1216 and 1217. The edge 1216 is the left edge of the shape 1215. The edge 1217 is the bottom edge of the shape 1215. In the first stage 1201, the DP loop marker 1220 indicates that the shapes 1205-1215 form a DP loop. That is, the three shapes are apart from each other at a distance smaller than the minimum same color spacing. The DP loop marker 1220 is depicted as a rectangle with hollow line edges and is placed in the middle of the three violating shapes 1205-1215. The DP loop marker 1220 is a rectangle in this example of FIG. 12 in order to share edges with the violating shapes 1205, 1210, and 1215 (e.g., to have the rectangle's edges coincide with the edges of the violating shapes). The DP loop marker in some embodiments also includes information that can be used to generate design solutions, such as a minimum same color spacing, identities of the violating shapes, etc. The first stage 1201 shows the child marker 1221 between the shapes 1205 and 1210; the child marker 1222 between the shapes 1210 and 1215; and the child marker 1223 between the shapes 1205 and 1215. Each of the child markers shares edges with the two shapes between which the child marker is located. The child marker also includes information that may be used to generate a design solution, such as a distance between the shared edges. The child markers 1221-1223 also identify three pairs of shapes—the shapes 1205 and 1210; the shapes 1210 and 1215; and the shapes 1205 and 1215—that form the DP loop in this example of FIG. 12. After process 1100 identifies (at 1110) all pairs of shapes that form a DP loop, the process 1100 then selects (at 1115) one of the identified pairs of shapes. The process uses the selected pair of shapes to generate a set of design solutions. The second stage 1202 in FIG. 12 shows that the pair of shapes 1210 and 1215 is selected. Next, process 1100 identifies (at 1120) edges to move. The design solutions that the process will generate require different combinations of these identified edges to move. In other words, the movements of these edges will be part of the design solutions to be generated. The process identifies edges of the two shapes of the selected pair based on a child marker that is placed between the two shapes. In some embodiments, the process identifies the edges that are shared with the child marker as the edges to move. For instance, as shown in the third stage 1203 in FIG. 12, the design solutions generator identifies the edge 1212 of the shape 1210 as an edge to move because the shape 1210 shares this edge with the child marker 1222. That is, the left edge of the child marker 1222 coincides with the right edge 1212 of the shape 1210. Similarly, the design solutions generator identifies the edge 1216 of the shape 1215 as an edge to move because the edge 1216 is shared by the shape 1215 and the child marker 1222. In some embodiments, process 1100 identifies additional edges to move. When the edges of the child marker that are not shared with the two shapes are aligned with other edges of the shapes, the process additionally identifies those other edges of the shapes as edges to move. For instance, the design solutions generator additionally identifies the edge 1211 and the edge 1217 as the edges to move as shown in the third stage 1203 in FIG. 12. The design solutions generator identifies these edges because the edge 1211 of the shape 1210 aligns with the top edge of the child marker 1222 and the edge 1217 of the shape 1215 aligns with the bottom edge of the child marker 1222. The process also identifies the directions in which the shapes should be moved. For instance, when the process identifies a vertical edge of a shape as an edge to move, the solution using this edge will require moving the shape horizontally away from the other shape of the pair. When the process identifies a horizontal edge of a shape to move, the design solution using this edge will require moving the shape vertically away from the other shape of the pair. Process 1100 then generates (at 1125) design solutions for the selected pair of shapes. The process in some embodiments generates design solutions based on the identified edges of the shapes. The process computes or retrieves from the child marker the distance between those two identified edges that are shared by the shapes and the child marker. The process also gets the minimum same color spacing from the DP loop marker. The process then computes the difference between the computed distance and the minimum same color spacing value. Based on the computed difference, the process generates three design solutions. A first of the three solutions requires moving a first edge of the two edges away from a second edge of the two edges by a distance greater than or equal to the computed difference. Similarly, the second of the three solutions requires moving the second edge away from the first edge by a distance greater than or equal to the computed difference. A third of the three solutions requires moving both the first and the second edges away from each other such that the total distance moved by the two edges is greater than or equal to the computed difference. In other words, each of these three solutions requires moving one or both of the two shared edges such that the total distance between the two edges is greater than or equal to the minimum same color spacing that is required by a design rule. The solutions 1-3 shown in the fourth stage 1204 in FIG. 12 are examples of three design solutions. The design solutions generator computes the difference between the minimum same color spacing and the distance between the edges 1212 and 1216. The solution 1 requires moving the edge 1216 of the shape 1215 to the right by a distance greater than or equal to the computed difference. The solution 2 requires moving the edge 1212 of the shape 1210 to the left by a distance greater than or equal to the computed difference. The solution 3 requires moving both of the edges 1212 and 1216 away from each other such that the distance between these two edges after movement is greater than or equal to the minimum same color spacing. For instance, the solution 3 may require moving the edge 1212 to the left by a half of the computed difference and the edge 1216 to the right by a half of the computed difference. FIG. 13 illustrates examples of the design layout 1200 when the three design solutions 1-3 illustrated in FIG. 12 are applied to the design layout 1200. In contrast to FIG. 12 in which the solutions are illustrated with the edges, FIG. 13 illustrates the design solutions with the shapes of the design layout 1200 when the solutions are applied to the design layout 1200. As shown in FIG. 13, the solution 1 requires moving the shape 1215 to the right by a distance greater than or equal to the computed difference. The solution 2 requires moving the shape 1210 to the left by a distance greater than or equal to the computed difference. The solution 3 requires moving both of the shapes 1210 and 1215 away from each other such that the distance between these two shape (i.e., the distance between the right edge of the shape 1210 and the left edge of the shape 1215) after movements is greater than or equal to the minimum same color spacing. Process 1100 also generates several additional design solutions based on the identified edges of the shapes that are not shared by the child marker and the two shapes. As described above, these edges of the shapes are aligned to an edge of the child marker. Each of these solutions requires moving one or more of such edges of the shapes such that no portion of a first shape of the two shapes is within the minimum same color spacing from any portion of a second shape of the two shapes. The design solutions generated based on the shared edges of the two shapes require moving the shapes either vertically or horizontally. The design solutions generated based on the non-shared edges of the two shapes require moving the shapes in a direction that is perpendicular to the direction of the movement of the shapes required by the design solutions generated based on the shared edges. For instance, as shown in the fourth stage 1204 in FIG. 12, the solutions 1-3 require horizontal movements of the edge 1212 of the shape 1210 and the edge 1216 of the shape 1215 while the solutions 4-6 requires vertical movements of the edge 1211 of the shape 1210 and the edge 1217 of the shape 1215. As described above, the solutions 1-3 are based on the shared edges (i.e., the edges 1212 and 1216). The solutions 4-6 are based on the non-shared edges (i.e., the edges 1211 and 1217). The solution 4 shown in the fourth stage 1205 in FIG. 12 requires moving the edge 1211 of the shape 1210 downwards by a certain distance so that no portion of the shape 1210 is within the minimum same color spacing from any portion of the shape 1215. As shown, the solution 4 thus requires moving the edge 1211 below the bottom edge of the child marker 1222. A corner formed by the edges 1211 and 1212 of the shape 1210 is apart from a corner formed by the edges 1216 and 1217 of the shape 1215 at a distance greater than the minimum same color spacing. The result of moving the edge 1211 is more apparently shown in FIG. 13. The solution 4 illustrated in FIG. 13 shows that the top portion of the shape 1210 and the bottom portion of the shape 1215 are further from each other and the DP loop formed by the shapes 1205-1215 is broken. That is, the shape 1215 and the shape 1210 are no longer within the minimum same color spacing. The solution 5 shown in the fourth stage 1204 in FIG. 12 requires moving the edge 1217 of the shape 1215 upwards by a certain distance so that no portion of the shape 1215 is within the minimum same color spacing from any portion of the shape 1210. As shown, the solution 5 thus requires moving the edge 1217 above the top edge of the child marker 1222. A corner formed by the edges 1216 and 1217 of the shape 1215 is apart from a corner formed by the edges 1211 and 1212 of the shape 1210 at a distance greater than the minimum same color spacing. The result of moving the edge 1217 is more apparently shown in FIG. 13. The solution 5 illustrated in FIG. 13 shows that the top portion of the shape 1210 and the bottom portion of the shape 1215 are further from each other and the DP loop formed by the shapes 1205-1215 is broken. The solution 6 shown in the fourth stage 1204 in FIG. 12 requires moving both of the non-shared edges 1211 and 1217. Specifically, the solution 6 requires moving the edge 1211 of the shape 1210 downward by a certain distance and moving the edge 1217 of the shape 1215 upwards by a certain distance so that no portion of the shape 1210 is within the minimum same color spacing from any portion of the shape 1215. A corner formed by the edges 1216 and 1217 of the shape 1215 is apart from a corner formed by the edges 1211 and 1212 of the shape 1210 at a distance greater than the minimum same color spacing. The result of moving the edges 1211 and 1217 is more apparently shown in FIG. 13. The solution 6 illustrated in FIG. 13 shows that the top portion of the shape 1210 and the bottom portion of the shape 1215 are further from each other and the DP loop formed by the shapes 1205-1215 is broken. Back to FIG. 11, process 1100 then determines (at 1130) whether there are more violating pairs of edges for which the process has not generated design solutions. When the process determines (at 1130) that there remains pairs of edges for which the process has not generated design solutions, the process loops back to 1115 to select one of the remaining pairs. Otherwise, the process ends. Such remaining pairs of edges in FIG. 12 are the two remaining pairs—one pair of shapes 1205 and 1210 and one pair of shapes 1205 and 1215. In the example of FIGS. 12 and 13, only three shapes are forming a DP loop and the solutions for one of the three pairs of edges are generated. However, one of ordinary skill in the art will realize that the design solutions generating techniques of some embodiments described in this example will be applicable to any number of shapes that are forming a DP loop. In addition, the edges shared by the child markers and the violating shapes are vertical edges in this example. Again, one of ordinary skill in the art will recognize that there could be cases when the shared edges are horizontal and the solutions generating technique of some embodiments are applicable to these cases as well. Additionally, the design rules used in this example included rules for minimum width, spacing, and pitch of shapes on a layer. One of ordinary skill in the art will recognize that other design rules, such as those for minimum contact or via enclosure, metal fill density, minimum gate length, and others are applicable to the shapes forming a DP loop. Moreover, the shape of the DP loop violation marker shown in this example is rectangle but a shape that represents a DP loop violation marker does not have to be a rectangle. The shape of the DP loop violation marker depends on the number of shapes that are forming a DP loop and the arrangement of those shapes. FIG. 14 conceptually illustrates a process 1400 that some embodiments perform to prioritize design solutions. The process 1400 in some embodiments is performed by the design solutions generator 700 described above by reference to FIG. 7. The process in some embodiments starts when the design solutions generator generates a set of design solutions for a DP loop violation in a design layout. Process 1400 begins by selecting (at 1405) a design solution for a DP loop violation in a design layout. The process selects a design solution from a set of design solutions generated for the DP loop violation. Next, the process computes (at 1410) a cost for applying the selected design solution to the design layout. Computing a cost for applying a design layout is described in detail further below by reference to FIG. 15. The process then determines (at 1415) whether there are more design solutions for which to compute costs. When the process determines (at 1415) that there are more design solutions generated for the DP loop violation of which the costs of applying to the design solution have not been computed, the process loops back to 1405 to select another design solution. Otherwise, the process prioritizes (at 1420) the design solutions based on the computed costs for the design solutions. In some embodiments, the process prioritizes the design solutions in the order of the lowest computed cost to the highest cost such that the design solution with the least cost to apply is prioritized the highest. FIG. 15 conceptually illustrates a process 1500 that some embodiments perform to compute a cost of applying a design solution to a design layout. The process 1500 in some embodiments is performed by the design solutions generator 700 described above by reference to FIG. 7. The process in some embodiments starts when the design solutions generator selects a design solution from a set of design solutions generated for a DP loop violation in a design layout. The process 1500 will be described by reference to FIG. 16 which illustrates a design solution to resolve a DP loop violation in a design layout 1600. FIG. 16 illustrates an example of a selected design solution that breaks a DP loop formed by shapes 1605, 1610, and 1615 of the design layout 1600. A design solutions generator (not shown in FIG. 16) such as the design solutions generator 700 described above by reference to FIG. 7 has generated and selected the design solution in this example. The selected design solution requires moving the shape 1615 to the right from its original position so that the shape 1615 is apart from the shape 1610 at a distance greater than or equal to the minimum same color spacing. Other shapes of the design layout 1600 are not shown in FIG. 16 for simplicity. Process 1500 begins by selecting (at 1505) a shape to move based on the selected design solution. As described, a design solution may require one or more shapes to be moved. The process selects one of the shapes that the solution requires to move. In the example of FIG. 16, the selected design solution requires moving only the shape 1215. Thus, the design solutions generator selects the shape 1215. At 1510, the process then defines an overlapping region and computes a cost associated with the overlapping region. In some embodiments, the process defines as the overlapping region the new region that the shape would occupy when it is moved. FIG. 16 illustrates that the design solutions generator has defined a set of regions 1625-1675. The original location 1620 of the shape 1615 before the shape 1615 was moved is depicted as a dotted rectangle in FIG. 16. The shape 1215 occupies a new region 1225 after being moved as shown. The solution generator defines the new region 1625 as the overlapping region and computes the cost for this region. The process in some embodiments computes the cost associated with the overlapping region based on the shapes that occupy at least a part of the overlapping region. In other words, the process finds all the shapes that will be in contact with the moved shape. For each shape found in the region, the process adds one unit cost (e.g., a value of 1) to the cost for the region. Next at 1515, process 1500 defines a minimum spacing region and computes a cost for the minimum spacing region. As described above, the minimum spacing is a minimum distance at which a design rule requires two shapes in a design layout, regardless of the shapes' assigned colors, to be apart from each other. The design solutions generator defines the regions 1630-1650 based on a minimum spacing as shown in FIG. 16. The heights of the shapes 1630 and 1650 is the minimum spacing. The radii of the quarter circles that the regions 1635 and 1645 are depicted as are the minimum spacing. The width of the region 1640 is the minimum spacing. The regions 1630-1650 are thus within the minimum spacing from the shape 1615 after the movement. The design solutions generator defines the regions 1630-1650 collectively as a minimum spacing region. The process in some embodiments computes the cost for the minimum spacing region in a similar manner that the process computes the cost for the overlapping region. That is, the process finds all shapes that occupy at least a portion of the minimum spacing region and adds unit costs for the shapes found in the region. At 1520, the process defines a minimum same color spacing region and computes a cost for the minimum same color spacing region. As described above, a minimum same color spacing is greater than a minimum spacing because the double patterning lithography technology requires two shapes that will be on the same mask to be further apart in the design layout than two shapes that will be on different masks are allowed to be apart from each other at the minimum. A minimum same color spacing is a minimum distance at which a design rule requires two shapes with the same color in a design layout to be apart from each other. As shown in FIG. 16, the design solutions generator defines the regions 1655 to 1675 as regions that are within the minimum same color spacing from the shape 1615 but not within the minimum spacing from the shape 1615. As a result, the regions 1655-1675 form a band wrapping the regions 1630-1655. The width of this band is the difference between the minimum same color spacing and the minimum spacing. These regions that are defined outside the minimum spacing but inside the minimum same color spacing are collectively defined as the minimum same color spacing region. In some embodiments, the process does not define any region on the side of the moved shape from which the shape has moved. For instance, the design solutions generator does not define any region on the left side of the shape 1615 because the shape 1615 has moved from left to right. The process in some embodiments computes the cost for the minimum same color spacing region in a similar manner that the process computes the cost for the overlapping region and the minimum spacing region. That is, the process finds all shapes that occupy at least a portion of the minimum same color spacing region and adds unit costs for the shapes found in the region. Furthermore, the process does not double-count a shape that is already accounted for in computation of costs for other regions. For instance, when a shape that occupies at least a portion of all three types of regions (the overlapping region, the minimum spacing region, and the minimum same color spacing region) is counted for the cost for the overlapping region, the same shape will not be counted for computing the cost for the minimum spacing region or the minimum same color spacing region). Process 1500 then performs (at 1525) local color checking if necessary. Local color checking is adjusting the cost computed for the minimum same color spacing region based on the color of the moved shape and the shapes found in the minimum same color spacing region. By performing local color checking, the process in some embodiments decreases the cost to zero units (e.g., no cost) when a color can be assigned to the moved shape without resulting in a minimum same color spacing violation. Local color checking will be described in detail below with reference to FIGS. 17 and 18. Next, process 1500 computes (at 1530) additional costs for moving a vertical interconnect access (via) shape if necessary. The process in some embodiments computes costs associated with a via shape when the via shape is not completely inside the moved shape after the movement. In such cases, the process treats the via shape as a shape that the solution requires to move. That is, the process performs 1510 through 1525 for this via shape. Computing additional costs for moving such via shape will be described in detail further below with reference to FIGS. 19 and 20. Process 1500 then computes (at 1535) any non-region-based cost for the design solution. A non-region-based cost is an additional cost to add to the overall cost of applying the design solution. The process computes this cost not based on the shapes found in the regions. For instance, the process computes a non-region-based cost based on the ratio of (1) the distance by which the selected design solution requires moving the selected shape and (2) a minimum spacing (e.g., the minimum distance by which two shapes of different colors should be apart). Next, the process adjusts (at 1540) the computed costs for the regions based on weights. The process in some embodiments assigns different weights to different shapes found in different regions. A weight could be a factor by which to multiply the cost calculated for a shape in some embodiments. In other embodiments, weights mean different amounts of costs assigned to different shapes in different regions. The process assigns the first most weight to an instance shape found in a region. As described above, an instance shape is a shape that belongs to a design instance, which is a group of shapes that are laid out in a pre-defined manner and can be reused for different locations of a design layout. That is, the shapes in a design instance are prearranged and immutable. The process in some embodiments assigns a cost of infinity to an instance shape found in the selected region. The process assigns the second highest weight to the shapes that connect to the moved shape. That is, a shape that falls in the overlapping region will be assigned to the second most weight. The process assigns the third highest weight to the shapes that are found in the minimum spacing region. The process assigns the fourth highest weight to via shapes that are found in a region. That is, an additional weight will be assigned to the via shape when a weight is already assigned to the via shape, for example, by falling in a minimum spacing region. The process assigns the fifth highest weight to any non-special shapes (e.g., shapes that are not via shapes or instance shapes, etc.) found in a region. The process assigns the sixth highest weight to the shapes found in the minimum same color spacing region. The process assigns the seventh highest weight to the non-region-based costs. The process assigns the eighth highest weight to the cost computed for moving a via shape. The order (i.e., the first highest to the sixth highest weight) that defines the amount of weight that the process assigns to different shapes in different regions as described above does not have to be followed in some embodiments. For instance, the process may assign more weight to via shapes than the shapes that would overlap with the moved shape. Moreover, in some embodiments, the different weight given to different shapes found in different regions are configurable. That is, the designer using the design solutions generator performing process 1630 can arbitrarily assign different costs to different shapes in different regions. Moreover, the process in some embodiments does not add a cost of infinity when the process finds an instance shape in the minimum same color spacing region. The process in these embodiments assigns a weight that the process assigns to a non-special shape to the instance shape. The process then determines (at 1545) whether there are more shapes to move for the design solution. When the process determines that there are more shapes to move, the process loops back to 1505 to select the next shape to compute costs for moving it. Otherwise, the process proceeds to 1550. At 1550, the process adds all computed costs. The resulting sum is the overall cost for the solution that includes costs computed for moving all the shapes the design solution requires to move. The process then ends. One of ordinary skill in the art will recognize that process 1500 is a conceptual representation of the operations used to compute costs for moving all the shapes that a design solution requires to move. The specific operations of process 1500 need not be performed in the exact order shown and described. The specific operations need not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. For instance, in some embodiments, process 1500 may adjust costs based on the weights while computing costs for each region at 1510, 1515, and 1520 instead of adjusting the computed costs at 1540. FIG. 17 conceptually illustrates a process 1700 that some embodiments perform to do local color checking. As described above, local color checking is adjusting the cost computed for the minimum same color spacing region based on the colors of the moved shape and the shapes found in the region. Process 1700 in some embodiments is performed by the design solutions generator 700 described above by reference to FIG. 7. The process in some embodiments starts after the design solutions generator has computed costs for the minimum same color spacing region. Process 1700 will be described by reference to FIG. 18. FIG. 18 illustrates an example of performing local color checking. Specifically, FIG. 18 illustrates six different color combinations 1801-1806 of the moving shape 1615 and two existing shapes 1810 and 1815 that fall within the same color checking region 1660, 1665, and 1670 of the design layout 1600 described above by reference to FIG. 16. For simplicity, shapes 1605 and 1610 that were forming a DP loop with the shape 1615 before the movement of the shape 1615 are not illustrated in FIG. 18. Process 1700 begins by determining (at 1705) whether the moved shape connects to any existing shape of the design layout after the movement. That is, the process determines whether there are existing shapes in the overlapping region As described above, the region 1625 is an overlapping region. When process 1700 determines (at 1705) that the shape being moved does not connect to any existing shape of the design layout, the process un-assigns (at 1710) the color of the shape if the shape had an assigned color so that the shape has no assigned color. Otherwise, the process proceeds to 1715 and thereby the moved shape retains its assigned color if any. The moved shape 1615 that occupies the overlapping region 1625 does not connect to any existing shapes in any of the six combinations 1801-1806 as shown in FIG. 18. Thus, the design solutions generator does not un-assign the color for the moved shape 1615 in combinations 1804-1806 in which the moved shape 1615 has an assigned color. The process then identifies (at 1715) all shapes with assigned colors that fall in the same color spacing region. As shown in FIG. 18, two shapes 1810 and 1815 occupy at least a portion of the minimum same color spacing region (e.g., the regions 1655-1675). These two shapes have assigned colors in all six combinations 1801-1806. The design solutions generator identifies these two shapes. Next, process 1700 determines (at 1720) whether the moved shape has an assigned color. The moved shape 1615 does not have an assigned color in the combinations 1801-1803. In the combinations 1804-1806, the moved shape 1615 has an assigned color (e.g., red). When the process determines (at 1720) that the moved shape has an assigned color, the process determines (at 1725) whether the identified shapes have a uniform color. Otherwise, the process proceeds to 1730 which will be described further below. The design solutions generator determines that the shapes 1810 and 1815 have a uniform color in combinations 1805 and 1806 among the combinations 1804-1806 in which the moved shape has an assigned color. When the process determines (at 1725) that the identified shapes do not have a uniform color, the process uses (at 1740) all the identified shapes to compute the cost. The identified shapes 1810 and 1815 have different assigned colors in the combination 1804 between the combinations 1804 and 1805. Thus, the design solutions generator adds two unit costs (e.g., a value of 2) for the minimum same spacing region. When the process determines (at 1725) that the identified shapes have a uniform color, the process determines (at 1735) whether the uniform color that these shapes have is different than the color assigned to the moved shape. When the process determines (at 1735) that the uniform color is different than the color assigned to the moved shape, the process sets (at 1745) the costs computed for the same color spacing region to zero unit cost (e.g., a value of zero). The identified shapes 1810 and 1815 have a uniform color in the combination 1805 between the combinations 1804 and 1805. Also, the uniform color that these two shapes have in the combination 1804 is different than the color assigned to the moved shape 1615 as shown in FIG. 18. Thus, the design solutions generator sets the cost for the minimum same color spacing region to zero as shown in FIG. 18. When the process determines (at 1735) that the uniform color is not different than the color assigned to the moved shape, the process uses (at 1740) all the identified shapes to compute the cost for the minimum same spacing region. When the process determines (at 1720) that the moved shape does not have an assigned color, the process determines (at 1730) whether the identified shapes have a uniform color. The identified shapes 1810 and 1815 have a uniform color in the combinations 1802 and 1803 among the combinations 1801-1803 in which the moved shape 1615 does not have an assigned color. In combination 1801, the two identified shapes does not have a uniform color as shown. When the process determines (at 1730) that the identified shapes have a uniform color, the process sets (at 1745) the costs computed for the same color checking region to zero unit cost. The design solutions generator sets the cost for the same color spacing region for the combinations 1802 and 1803 because the identified shapes 1810 and 1815 have a uniform color. When the process determines (at 1730) that the identified shapes do not have a uniform color, the process uses (at 1740) all the shapes to compute the cost for the minimum same spacing region. The design solutions generator adds two unit costs (e.g., a value of 2) for the minimum same spacing region for the combination 1 as shown because the identified shapes 1810 and 1815 have different colors as shown. The process then ends. By performing process 1700, the design solutions generator of some embodiments determines that the shapes found in the minimum same color spacing do not contribute to the overall cost of applying the design solution when the shapes found in the region and the moved shape do not violate the minimum same color spacing rule. For the combination 1802 and 1803 shown in FIG. 18, the design solutions generator can assign to the moved shape 1615 a color different than a uniform color that is assigned to the shapes 1810 and 1815 without violating the rule. This is because the two shapes 1810 and 1815, which are within the minimum same color spacing from the moved shape 1615, has a uniform color in combinations 1802 and 1803 and the moved piece and each of the two shapes 1810 and 1815 can have different colors. In contrast, the design solutions generator cannot assign a color to the moved shape 1615 without violating the rule in combination 1. This is because assigning to the moved shape 1615 a color that is different than the color assigned to the shape 1810 to avoid violating the rule will cause the moved shape 1615 and the shape 1815 to violate the rule. FIG. 19 conceptually illustrates a process 1900 that some embodiments perform to compute additional costs for moving a vertical interconnect access (via) shape. Process 1700 in some embodiments is performed by the design solutions generator 700 described above by reference to FIG. 7. The process in some embodiments starts after a shape, that a design solution requires to move, is selected. The process begins by receiving (at 1905) a selected shape. FIG. 20 illustrates a design layout that includes shapes 1 and 2 and via shapes 1 and 2. Other shapes that the design layout includes are not depicted in the figure for simplicity. The figure also illustrates two design solutions 1 and 2. The solution 1 requires moving shape 1 and the via shape 1 to the left. The solution 2 requires moving the shape 2 and the via shape 2 to the right. As shown, the via shape 2 is completely within the shape 2, while the via shape 1 only partially overlaps with shape 1. The design solutions generator (not shown in FIG. 20) has selected the shape 1 for the solution 1 and the shape 2 for the solution 2. Process 1900 then determines (at 1910) whether the selected shape overlaps with a via shape. When the process determines (at 1910) that the selected shape does not overlap with a via shape, the process ends. Otherwise, the process adds (at 1915) an additional unit cost (e.g., a value of 1) to the overall cost for the solution. Since the shapes 1 and 2 both overlap with via shapes as shown in FIG. 20, the design solutions generator adds a unit cost for each of the solutions 1 and 2. Next, the process determines (at 1920) whether the via shape has a non-overlapping portion in the direction of the movement required by the design solution. When the process determines (at 1910) that the via shape does not have a non-overlapping portion in the direction of the movement required by the design solution, the process ends. Otherwise, the process computes (at 1925) the cost for moving the via shape. That is, when the via shape has a non-overlapping portion in the direction of the required movement, the process defines an overlapping region, a minimum spacing region, and a minimum same color spacing region based on the position of the non-overlapping portion of the via shape to which the via shape is moved. This is because when the via shape is not completely inside the selected shape, the cost for moving the non-overlapping portion of the via shape will not be accounted for in the cost computed for moving the selected shape. In other words, because this non-overlapping portion of the via shape is moving together with the selected shape, some design violations may result from moving this portion in addition to the potential design violations that would result from moving the selected shape. The via shape 2 shown in FIG. 18 does not have a non-overlapping portion because the via shape 2 is completely inside the shape 2. Thus, the design solutions generator will not perform an additional cost computation for the via shape 2. Assuming that via shape 2 is not completely inside the shape 2 and has some non-overlapping portion on the left side of the shape 2, this non-overlapping portion would not have triggered the design solutions generator to compute the additional cost because that portion would not be in the direction of the movement that the solution 2 requires (i.e., to the right). On the other hand, the via shape 2 has a non-overlapping portion on the left side of the shape 1. This portion is in the direction of the movement that the solution 1 requires. Thus, the design solutions generator will compute the additional cost for the via shape 1. FIG. 21 conceptually illustrates an example architecture for the design solutions generator 700 and a design optimizer 2105 of some embodiments. Specifically, FIG. 21 illustrates that the design solutions generator 700 generates and prioritizes design solutions for resolving DP loop violations in a design layout and the design optimizer selects and applies a generated solution to the design layout. This figure illustrates the design layouts 705, the DP loop violation markers 710, the design solutions generator 700, the design rules 735, and the design solutions 740 which are described above by reference to FIG. 7. The design solutions generator 700 includes the marker analyzer 715, the loop edge pair identifier 720, the solutions generator 725, and the solutions prioritizer 730 which are also described above by reference to FIG. 7. FIG. 21 illustrates that the solutions prioritizer 730 includes a solution selector 2160, a shape selector 2125, a region definer 2130, a shape finder 2145, a cost calculator 2140, a local color checker 2135, a sorting engine 2155, and a cost adjuster 2150. The solution selector 2160 retrieves or receives generated design solutions from the solution generator 725 or the design solutions repository 740. The solution selector 2160 selects a design solution to process and sends the selected design solution to the shape selector 2125. The shape selector 2125 selects a shape that the selected design solution requires to move. The region definer 2130 then defines the regions in the design layout based on the design rules and the position of the selected shape after the movement. These regions include an overlapping region, a minimum spacing region, a minimum same color spacing region, etc. The shape finder 2145 finds the shapes that fall in these defined regions. The shape finder 2145 also identifies the region to which a shape belongs and ensures that one shape does not get counted for more than one region. The cost calculator 2140 computes the cost for each defined region first based on the number of shapes found in each region. The cost calculator 2140 also performs local color checking using the local color checker 2135. Local color checking is described above by reference to FIGS. 17 and 18. The cost calculator 2140 also counts special shapes like via shapes and instance shapes found in computation of the cost for the defined regions. The cost calculator in some embodiments then adjusts the calculated cost using the cost adjuster 2150. The cost adjuster 2150 adjusts the cost so far calculated by, for example, assigning different weights to different shapes found in different defined regions. The cost adjustment operations are described above in detail by reference to FIG. 15. Once the cost calculator computes the cost of moving a selected shape, the cost calculator computes a cost for moving another shape that the selected design solution requires to move. When the cost calculator is done computing the cost for all shapes for the selected design solution, the cost calculator 2140 computes the cost for another design solution. Once the cost calculator 2140 computes all costs for all design solutions, the sorting engine 2155 prioritizes the design solutions based on the computed costs. For instance, the sorting engine 2155 sorts the design solutions for the DP loop violation in the order of the lowest to the highest cost. In some embodiments, the solutions prioritizer 730 deposits the prioritized design solutions in the design solutions repository 740. As shown in FIG. 21, the design optimizer 2105 includes a design solution analyzer 2115, a layout modifier 2120, and an interface 2110. The design optimizer 2105 in some embodiments receives or retrieves the prioritized design solutions for addressing the DP loop violation, selects a design solution to use, and changes the design layout based on the selected design solution. The design solution analyzer 2115 selects a design solution from the prioritized design solutions. In some embodiments, the design solution analyzer 2115 selects the design solution with the highest priority without analyzing the design solution to see whether applying the solution creates new design rule violations under the assumption that the solution with highest priority has the least chance of causing new design violations. In other embodiments, the design solution analyzer 2115 analyzes each design solution from the highest priority solution to the lowest priority solution until it finds a design solution that does not cause new design rule violations. The design solution analyzer 2115 selects the first such solution. The design solution analyzer 2115 then sends the selected design layout to the layout modifier 2120, which will change the design layout by applying the selected design solution. In some cases, all design solutions generated and prioritized for a DP loop violation cause new design rule violations. In such cases, the design solution analyzer 2115 in some embodiments selects the design solution that causes the least number of design rule violations. In some such embodiments, the design solution analyzer 2115 uses the priorities assigned to the design solutions when there are two or more design solutions that cause the least number of design rule violations. In some embodiments, the design analyzer 2115 also uses the type of design violation when selecting a design solution. One of the ordinary skill in the art will recognize that there are many other ways of selecting a design solution from a group of prioritized design solutions. For instance, the design analyzer 2115 may select a design solution that causes a minimum same spacing rule violation over a design solution that causes a new DP loop violation. When all design solutions generated and prioritized for a DP loop violation cause a new design rule violation, the design solution analyzer 2115 may use the interface 2110 to take further action instead of applying a design solution that will cause one or more design rule violations. For instance, the design solution analyzer 2115 in some embodiments notifies the designer that all of the generated design solutions cause new design rule violations. In other embodiments, the design solution analyzer 2115 notifies through the interface 2110 another module (not shown) which resolves a DP loop violation by introducing splicing graphs in the shapes of the design layout. Resolving a DP loop violation using splicing graphs is described in detail below in Section III. In some embodiments, the design solutions generator 700 and the design optimizer 2105 are stand-alone software applications. In other embodiments, the design solutions generator 700 and the design optimizer 2105 are parts of a single software application that generates and uses design solutions. FIG. 22 conceptually illustrates a process 2200 that some embodiments perform to generate and prioritize design solutions for a DP loop violation in a design layout and to use the design solutions to remedy the DP loop violation in the design layout. The process in some embodiments is performed by a software application that includes the design solutions generator 700 and the design optimizer 2105 or by a system on which the design solutions generator 700 and the design optimizer 2105 are executed. The process 2200 is performed when a user executes the software application or runs the system in order to modify a design layout that contains a DP loop violation. As shown, process 2200 retrieves or receives (at 2205) a DP loop violation marker that indicates that a set of shapes in the design layout forms a DP loop. A DP loop violation marker is described above in detail in subsection II.A. The process retrieves or receives the marker from a repository such as the markers repository 705 described above by reference to FIG. 7. Next, the process generates (at 2210) several design solutions based on the received marker. An example set of operations that the process 2200 performs to generate design solutions is described above by reference to FIG. 11. The process in some embodiments stores the generated design solutions in a repository such as the design solutions repository 740 described above by reference to FIGS. 7 and 21. Process 2200 then prioritizes (at 2215) the generated design solutions based on the costs of applying the design solutions. An example set of operations that the process 2200 performs to prioritize the generated design solutions for resolving a DP loop violation is described above by reference to FIG. 14. The process in some embodiments then selects (at 2220) the next highest priority design solution among the prioritized design solutions. The process retrieves the design solution and the design layout that contains the DP loop. The process changes the design layout according to the design solution without committing the changes to the design layout in some embodiments (e.g., without saving the design layout as changed or without depositing the changed layout into a repository such as the design layouts repository 740 described above by reference to FIGS. 7 and 21). Based on the changed design layout, the process determines (at 2225) whether the selected design solution causes any new design violations in the design layout. In order to determine design rule compliance, the process retrieves the design rules and verifies the changed design layout against each of the retrieved design rules. When the process determines (at 2225) that the design solution causes one or more new design violations in the design layout, the process proceeds to 2230 which will be described further below. After process 2200 determines (at 2225) that the design solution does not cause any new design violations in the design layout, the process modifies (at 2235) the design layout based on the selected design solution. The process in some embodiments modifies the design layout by committing the changes made to the design layout. The process then ends. When the process 2200 determines (at 2225) that the selected design solution causes one or more new design violations in the design layout, the process determines (at 2230) whether there are any generated design solutions that the process has not verified yet. When there are more design solutions left, the process loops through operations 2220 and 2225 in order to continue examining the remaining design solutions. When there are no more design solutions left, the process performs (at 2240) a set of operations for having no design solution that resolves the DP loop violation without resulting in new design rule violations. The set of operations includes operations that the process performs to select the highest priority design solution and applying the selected design solution to the design layout that contains the DP loop. The set of operations may also include operations that the process performs to resolve the DP loop violation by introducing splicing graphs in the shapes of the design layout. Resolving a DP loop violation using splicing graphs is described in detail below in Section III. The set of operations may also include operations that the process performs to report to the user so that the user can make a decision on whether to use any of the generated design solutions. In some such embodiments, the process notifies the user (e.g., via a pop up message or a message log) that all of the generated design solutions for the design violation cause new design rule violations and ends. One of ordinary skill in the art will recognize that process 2200 is a conceptual representation of the operations used to receive a marker, generate design solutions based on the marker, select a design solution, and apply the selected design solution to remedy a design violation. The specific operations of process 2200 need not be performed in the exact order shown and described. The specific operations need not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. For instance, in some embodiments, process 2200 is performed by one or more design software applications that are executing on one or more computers. Specifically, resolving the DP loop violation by introducing (at 2240) splicing graphs to the shapes of the design layout may be performed by one software and generating and prioritizing design solutions as well as selecting and applying a design solution may be performed by another software. FIG. 23 illustrates example data structures for DP loop violation markers, design solutions, design rules, and design layouts used by some embodiments of the invention. As shown, a data structure 2305 for a DP loop marker in some embodiments includes a violation type 2306 to indicate that the marker is for a DP loop violation, a reference 2307 to the design layout in which the DP loop is formed, an identification of the layer of the design layout in which the DP loop is formed, and coordinates of the marker. The data structure 2310 for a design rule in some embodiments includes a rule type (e.g., a minimum spacing rule, a minimum same color spacing rule, etc.) and a rule value that corresponds to the rule type (e.g., a minimum distance between two shapes having the same assigned color, a minimum distance between two shapes of any color, a minimum width of a shape, a minimum size of a shape, etc.). A data structure 2315 for a design solution in some embodiments includes a reference 2316 to the marker in which information regarding the DP loop violation that the solution can remedy is included. The data structure 2315 also includes a list of shapes that need to be moved and their target coordinates for each corner of the shape. For each shape in the list, the data structure include a cost 2317 and a color 2318. The cost 2317 will store the value of the cost associated with moving this particular shape. The color 2318 stores a value that represents a color assigned to the shape. In some embodiments, the data structure 2315 for a design solution includes the marker, instead of having a reference to the data structure 2305. A data structure 2320 for a design layout in some embodiments includes a list of layers that are in the design layout. Each of the layers in the list includes information about the layer's coordinates system and a list of sets of coordinates. Each set of coordinates is a set of coordinates of vertexes of a segment or shape on the layer in some embodiments. Also, the data structure 2320 includes colors 2321 and 2322 for storing two values that represent the two colors to be assigned to the shapes in each layer. FIG. 24 conceptually illustrates a process 2400 of some embodiments for introducing splicing graphs in order to resolve a DP loop violation in a design layout region of an IC. The process 2400 begins at 2405 when it receives the design layout that includes a DP loop along with a pitch requirement for the exposures. In some embodiments, the pitch requirement is the minimum width of a shape plus the distance that two shapes can be from each other and still be printed in the same exposure, while in other embodiments, the pitch requirement is the minimum distance that two shapes can be from each other and still be printed in the same exposure. FIG. 25 illustrates a design layout 2500 and pitch requirement 2510. The design layout 2500 includes nine shapes 2515-2560. The design layout 2500 includes a DP loop formed by shapes 2515, 2520, and 2525 In order to resolve a DP loop violation, some embodiments use shape graphs in addition to the other graphs described above. Returning to process 2400, the process 2400 builds (at 2410) a shape graph to represent the associations between shapes. In some embodiments, the shape graphs are used for the assignment of colors to the shapes. FIG. 26 conceptually illustrates a process 2600 of some embodiments for drawing a shape graph. The process begins at 2605 by receiving a list of shapes for a particular design layout region. Design layout region 2500 of FIG. 25 is an example of a design layout region that would be received by process 2600. FIG. 27 illustrates the completed shape graph for design layout region 2500. The received list is ordered such that linked shapes are near each other in some embodiments, whereas in other embodiments the list is more random. Some embodiments provide the list as pairs of shapes that are within the pitch requirement, whereas other embodiments provide the list as each shape with all of other shapes that are within the pitch requirement from the shape. The process 2600 then retrieves (at 2610) the first shape in the list. The process draws (at 2615) a node in the shape graph corresponding to the shape retrieved (at 2610) above. FIG. 27 illustrates a shape graph 2700 for the region 2500. Taking the first shape retrieved as shape 2515 (this would not necessarily be the case, as shape 2515 might not be the first shape in the list), node 2705 (node “1”) would be drawn corresponding to shape 2515. Next, the process 2600 determines (at 2620) if the retrieved shape is within the pitch requirement from another previously-drawn shape. For example, referring to FIG. 25, shapes 2515 and 2520 are within the pitch requirement 2510. Of course, there is not a previously-drawn shape when the first shape is just drawn. The process 2600 proceeds to 2630 to determine whether there are any unprocessed shapes in the list (e.g., whether there are any more shapes to add to the shape graph). Otherwise, the process 2600 ends. If there are remaining unprocessed shapes, the process 2600 returns to 2610 to retrieve the next shape from the list. However, if the retrieved shape is not the first shape and there is a previously-drawn shape that is within the pitch requirement from the retrieved shape, the process 2600 draws (at 2625) a line between the nodes corresponding to the retrieved shape and the previously-drawn shape. In reference to the example, if after drawing node 2705, the next retrieved shape is shape 2520 (drawn as node 2715 in FIG. 27), then line 2710 between the two nodes 2705 and 2715 representing the shape 2515 and 2520, respectively, is drawn in the shape graph. The process 2600 continues in this manner until it has drawn all the nodes and links representing the shapes and their associations. Once the process 2600 determines (at 2630) that all of the shapes have been processed, the process ends. FIG. 27 illustrates the completed shape graph for design layout region 2500, illustrating the connections between the nine shapes 2515-2560 in the design layout region. One of the ordinary skill in the art will recognize that the process can use a shape graph to determine whether the shapes represented by the shape graph forms a DP loop. That is, the process determines that the design layout includes a DP loop violation when there is a loop formed by an odd number of nodes in a shape graph. As shown in FIG. 27, three nodes 2705, 2715, and 2720 (representing the shapes 2515, 2520, and 2525, respectively) form a loop in the shape graph 2700 and this verifies that the design layout 2500 includes a DP loop. Returning to process 2400, the process defines a group of shapes based on the shape graphs the process has built at 2410. In some embodiments, the process defines as a group of all DP loop-forming shapes and the shapes that are represented as nodes that are directly or indirectly linked (by lines drawn) to the nodes that represent the DP loop-forming shapes in a shape graph. As shown in FIG. 27, the nodes 2725-2750 are directly or indirectly linked to the nodes 2705, 2715, and 2720 which represent shapes 2515, 2520, and 2525, respectively, that form the DP loop. Nodes 2725-2750 represent shapes 2530-2560. The process 2400 thus defines a group of shapes that includes nine shapes 2515-2560. The process 2400 next identifies (at 2415) the critical shape segments (“CSSs”) and associates each CSS with a shape ID that represents the geometry which includes the particular CSS. As described above, critical shape segments in some embodiments are portions of a shape that are within the pitch requirement of another shape. As such, the CSS cannot be printed in the same exposure as the shape to which it is too close. FIG. 28 illustrates the shapes 2515-2560 of FIG. 25 after each CSS has been identified and marked (at 2415) as a CSS 2805. For instance, shape 2560 includes a single CSS 2890 that is within the minimum pitch requirement 2510 from shape 2555 (specifically, the section of shape 2555 indicated by CSS 2880), while the remainder of shape 2560 is not within the minimum pitch requirement of any other shapes, and thus is not marked as a CSS. Likewise, the rest of the CSSs 2810-2890 are identified on the remaining shapes 2515-2555. As shown in FIG. 28, in some cases a single shape (e.g., 2515) may have multiple CSSs (e.g. 2810 and 2815). In other cases (not shown), a shape may have no CSSs (e.g., no portion of the shape on the target layer is within the minimum pitch requirement of any portion of another shape on the target layer). In addition to identifying each CSS, the process 2400 associates (at 2415) the shape ID with each CSS, so that the CSS is linked to the shape that includes it. As shown in FIG. 28, for instance, shape 2515 may be designated as shape “1” while CSS 2810 may be designated as CSS “a.” The process transfers the shape ID to the CSS ID, such that CSS “a” becomes CSS a[1]. As another example, shape 2520 may be designated as shape “2” while CSSs 2815 and 2820 are designated as CSSs “b” and “c,” respectively. Consequently, the process will transfer the shape ID to the CSS IDs, so that CSSs “b” and “c” become b[1] and c[2]. The other CSSs are likewise associated with their respective shape IDs. Some embodiments utilize the CSS for shape mapping in later stages of the decomposition process (e.g., for finding optimal decomposition solutions). The process next associates (at 2420) CSSs to other CSSs to indicate the associated CSSs will need to have alternate assigned colors (i.e., to be printed during separate exposures). FIG. 29 illustrates the shapes and CSSs from FIGS. 25 and 28 after they have been associated through a link 2905. The link is a virtual or conceptual layer that is not printed on any exposures or placed on any masks. Some embodiments do not use a link, and instead just use pairs of associated CSSs. As shown, links associate CSS 2810 to CSS 2825, CSS 2825 to CSS 2835, and CSS 2835 to CSS 2840. Some embodiments also treat CSSs that are indirectly linked through a combination of the links and other CSSs as linked (e.g. CSS 2810 is associated with CSS 2835 through two links and CSS 2825). Likewise, other links associate the other CSSs 2815, 2820, 2830, and 2845-2890. The dashed ovals 1610-1660 indicate six different sets of associated CSSs. Process 2400 continues (at 2425) by building a CSS graph and partitioning the CSS graph into sub-graphs. Some embodiments use the sub-graphs to verify whether CSSs can have different colors assigned (e.g., sent to two different masks). FIG. 30 conceptually illustrates a process 3000 of some embodiments for generating and partitioning a CSS graph. FIG. 31 illustrates the CSS graph 3100 drawn based on the example design layout region given above in reference to FIGS. 25-29. Each CSS from the design layout region is a vertex in the CSS graph. Two vertices are “adjacent” if there is a link that touches both of the corresponding CSSs (e.g., if there is a line between the two nodes in the resulting CSS graph). The node names in CSS graph 3100 correspond to the CSSs from design layout region 2500: in this example, the nodes are named “a” to “r” (omitting the letter “1”), with each node name corresponding to one of the CSSs 2810-2890. As shown, the process 3000 receives (at 3005) a list of CSSs and the links between them. Some embodiments receive this information as a list of CSSs, and for each CSS, all CSSs that are adjacent to that CSS. Other embodiments receive a list of pairs of adjacent CSSs. Still other embodiments receive the information in other forms. The process retrieves (at 3010) a next CSS from the list and draws (at 3015) a node corresponding to that CSS. The first CSS in the example list is CSS 2810, which is designated as node “a” and placed in the CSS graph as node 3105. Some embodiments will not necessarily start at the end of a series of linked CSSs (e.g., CSS 2815 might be the first CSS retrieved from the list). The process 3000 then determines (at 3020) whether the current CSS is adjacent (e.g., directly connected through a link) to any previously drawn CSS. Some embodiments traverse the list of CSSs to determine whether the current CSS is part of any pairs, whereas other embodiments have a list of all nodes adjacent to the current node. If there are other adjacent previously drawn CSS nodes, the process draws (at 3021) a line (or link) connecting the current CSS node to the previously drawn CSS node. Since the current CSS node is the first drawn node, there are no previously-drawn adjacent CSS nodes. Although CSS 2810 is adjacent to CSS 2825, no line will be drawn the first time because CSS 2825 is not yet drawn into the sub-graph. This line will be drawn later, once a node for CSS 2825 is drawn. If the current CSS node is adjacent to a previously drawn CSS node, then the process draws (at 3021) a line between the adjacent nodes, and returns to 3020 to determine whether there are any more previously drawn nodes adjacent to the current node. Once there are no more previously-drawn adjacent CSS nodes, the process 3000 determines (at 3025) whether there are any unprocessed CSSs in the list. If all CSSs have been processed, then the process 3000 proceeds to 3030. When the process 3000 determines (at 3025) that there are more remaining CSSs, the process returns to 3010 to retrieve the next CSS from the list, and adds a node to the graph for the CSS. This CSS is now the current CSS. The process 3000 then repeats operations 3015-3025 for the new current CSS. In the example, after drawing node 3105, the process would return to select the next CSS (e.g., CSS 2825) as the current CSS, draw the node 3115, and determine whether node 3115 is adjacent to any previously drawn nodes. Node 3115 is adjacent to nodes 3105 and 3125. If only node 3105 is already drawn, then only the line between nodes 3105 and 3115 would be drawn at that time. Some embodiments do not necessarily take a continuous path through the CSSs, so after drawing node 3105, the next CSS selected might not be adjacent to CSS 2810 (e.g., CSS 2870). Eventually, after processing all of the CSSs, all the nodes of the CSS graph would be drawn, as would all edges indicating the adjacent CSSs. When all CSSs have been added to the CSS graph 3100, the process 3000 partitions (at 3030) the associated CSSs into sub-graphs by identifying sets of linked CSS nodes as sub-graphs. In other words, each sub-graph includes a set of CSS nodes that are directly or indirectly linked to each other. The CSS nodes in a first sub-graph may not be linked to any CSS nodes in another sub-graph. Thus, in the example shown in FIG. 31, the CSS graph 3100 is partitioned into six sub-graphs 3140-3165. While the process 3000 illustrates one example of a process to generate a CSS graph, one of ordinary skill in the art will recognize that other processes may be used to generate a CSS graph. For example, some embodiments may initially order the CSSs, making the generation of the CSS graph less computationally intensive. Furthermore, one of ordinary skill in the art will recognize that the CSS graph generation (and partitioning of the CSS graph into sub-graphs) may occur at different times within the overall process of resolving a DP loop. The process 2400 next determines (at 2430) whether the DP loop violation is unresolvable by way of introducing splicing graphs. In some embodiments, the process uses CSS graphs to determine whether the DP loop violation is resolvable. FIG. 32 illustrates an example of a design layout region 3200 that includes a DP loop violation that is not resolvable by introducing splicing graphs. As shown, the design layout region 3200 is composed completely of the CSSs and the links. The example design layout region 3200 includes five shapes 3215-3235. Each of the shapes 3215-3235 is also a single CSS, corresponding to a single node in a CSS graph. FIG. 32 illustrates a sub-graph 3250 corresponding to the design layout region 3200. The sub-graph (which is also a complete CSS graph for the design layout region 3200) includes five nodes “a” to “e,” which correspond to the five shapes 3215-3235 in some embodiments. In some embodiments, the process determines that the DP loop violation is not resolvable by way of introducing splicing graphs when the CSS graph includes a loop formed by an odd number of nodes. As described above, a CSS is a portion of a shape that must be sent to a different mask than its neighboring CSS. A shape is segmented into one or more CSSs in order to introduce splicing graphs between them. Thus, a CSS may not be further split or segmented (i.e., a single CSS may not have two assigned colors). A loop formed by an odd number of CSSs, therefore, indicates that the DP loop formed by the shapes that include these loop-forming CSSs cannot be resolved by introducing splicing graphs. As shown in FIG. 32, there is a loop formed by three nodes “b”, “c”, and “d” which correspond to the CSSs 3220, 3225, and 3230. The process accordingly determines that the DP loop formed by the three shapes is not resolvable. In contrast, the DP loop formed by the shapes 2515, 2520, and 2525 shown in FIG. 29 is resolvable because the sub-graph representing the CSS of these three shapes includes a loop as shown in FIG. 31. When the process 2400 determines (at 2430) that the DP loop violation is resolvable, the process proceeds to 2440, which will be described below. Otherwise, the process reports (at 2435) that the DP loop violation is not resolvable by introducing splicing graphs. In some embodiments, the process 2400 attempts to resolve the DP loop violation by moving the shapes in the design layout as described in Section II above. The process 2400 next introduces (at 2440) a minimum number of splicing graphs in the shapes of the defined group. The process 2400 in some embodiments performs a coloring process to minimize the number of splicing graphs to introduce while assigning colors to shapes. FIG. 33 conceptually illustrates a coloring process 3300 for some embodiments. The process 3300 begins by receiving (at 3305) a group of shapes, CSSs, and links for a design layout that includes the DP loop. In some embodiments, the group of shapes, CSSs, and links is an unordered roster of the shapes that are in the defined group with a list of the CSSs and links for each shape. As described above, this group of shapes includes DP loop forming shapes and the shapes associated with the DP loop-forming shapes. For instance, the process might receive the shapes, CSSs, and links for the defined group that includes nine shapes 2515-2560, in design layout 2500, along with CSS sub-graphs 3140-3165 and the shape graph 2700 that includes nodes that represent the nine shapes. The process 3300 then un-assigns (at 3310) colors from the shapes in the defined group if any of the shapes has assigned colors already. Next, the process 3300 selects (at 3315) a shape in the group based on certain criteria and selects the shape on top of the order. The criteria in some embodiments include (1) a number of CSSs included in a shape (2) a number of splicing graphs that a shape has so far (3) whether a shape is partially colored, etc. This selection operation is described in detail by reference to FIG. 34 below. When the process 3300 has not selected and colored any shape yet, the process initially selects a shape that is represented by a node in the shape graph that has the least number of links. For instance, the process would select node 5 of the shape graph 2700. At 3320, the process 3300 selects a CSS that does not have an assigned color and assigns a color to the selected shape. When the selected shape is the first shape of the group that the process has selected, the process can select any CSS of the selected shape and assigns one of the two available colors. When the selected shape is not the first shape of the group that the process has selected, the process selects a CSS that is next to a CSS that has an assigned color. The process assigns the same color to the selected CSS to avoid introducing an unnecessary splicing graph. The process 3300 then assigns (at 3330) colors to all CSSs that are associated with the selected CSS. As described above by reference to FIG. 29, CSSs are associated when they are directly or indirectly linked. Thus, in some embodiments, the process identifies the CSSs that are associated with the selected CSS using a CSS sub-graph that includes a node representing the selected CSS. For instance, if the process had selected CSS 2845 shown in FIG. 29 to color, the process would identify CSSs 2810, 2825, and 2835 as the CSSs associated to CSS 2845 using CSS sub-graph 3140 shown in FIG. 31. The process then assigns colors to these associated CSSs by alternating colors so that a neighboring pair of CSSs does not have the same color. For instance, if the process had assigned a first color to CSS 2845, the process would assign a second color to CSSs 2810 and 2835 and assign the first color to CSS 2825. Next, the process 3300 determines (at 3330) whether there are more CSSs of the selected shape that do not have an assigned color yet. When there are such CSSs left, the process goes back to 3320 to select a next CSS to assign a color. When the process 3300 determines (at 3330) that there are no more CSSs of the selected shape that do not have an assigned color yet, the process 3300 determines (at 3335) whether there are more shapes of the group that have not been fully colored (e.g., whether there are more shapes of the group that have CSSs that do not have an assigned color). When there are such shapes left, the process goes back to 3315 to select a next shape from the remaining shapes of the group that have not been fully colored. A more detailed example of performing this coloring process will be described further below by reference to FIGS. 35A-B. Also, it is to be noted that the coloring process 3300 in some embodiments does not have to use CSS sub-graphs or shape graphs. That is, the process in these embodiments finds the associations among CSSs and shapes and utilizes the associations to minimize the number of splicing graphs to introduce while assigning colors to the shapes and CSSs of the shapes. Moreover, one of the ordinary skill in the art would recognize that the coloring process 3300 is capable of resolving a situation when two or more DP loops are formed by in a single group of associated shapes. FIG. 34 conceptually illustrates a process 3400 performed by some embodiments to select a shape of a defined group to assign color(s). The process 3400 begins by receiving (at 3405) a group of shapes, CSSs, and links for a design layout that includes a DP loop. The group of shapes includes shapes that form the DP loop and shapes that are associated with the DP loop-forming shapes as described above. These shapes are being colored by the coloring process 3300 described above. The process 3400 receives shapes that are not colored or partially colored. That is, some or all of CSSs of each received shape do not have an assigned color yet. Next, the process 3400 selects (at 3410) shapes that do not have a splicing graph (e.g., shapes that do not have assigned colors or have a uniform assigned color). The process then determines (at 3415) whether only one shape is selected. That is, the process determines whether there is only one shape that does not have a splicing graph. If so, the process is done with selection of a shape and the process ends. Otherwise, the process proceeds to 3420 to determine whether none of the received shapes is selected (e.g., whether there is no received shape that has a splicing graph or there are two or more received shapes that have a splicing graph). When the process determines (at 3420) that there are two more received shapes that have a splicing graph, the process proceeds to 3425, which will be described further below. When the process determines (at 3420) that there is no received shape that has a splicing graph, the process selects received shapes that are partially colored (e.g., the process selects received shapes that have CSSs that do not have an assigned color). Next, the process 3400 determines (at 3435) whether only one such shape is selected (e.g., whether there is only one received shape with no splicing graphs that is partially colored). When only one such shape is selected (i.e., when the number of partially colored shapes among the shapes with no splicing graphs is one), the process is done with shape selection and the process ends. Otherwise, the process determines (at 3445) whether none of such shapes are selected (e.g., whether none of the received shapes with no splicing graphs is partially colored or two or more received shapes with no splicing graphs are partially colored). When the process 3400 determines (at 3445) that none of the received shapes with no splicing graphs is partially colored (i.e., all received shapes with no splicing graphs are not colored), the process 3400 proceeds to 3455, which will be described further below. When the process 3400 determines (at 3445) that two or more received shapes with no splicing graphs are partially colored, the process selects (at 3450) shapes with the least number of CSSs. The process 3400 then determines (at 3460) whether only one such shape is selected (i.e., whether there is only one received shape with no splicing graphs that has the least number of CSSs). When only one such shape is selected, the process is done with selection of a shape and the process ends. Otherwise, the process proceeds to 3470 to select a shape based on a non-tying criterion. For instance, the process randomly selects one of the selected shapes. The shape that the process selects thus has the least number of CSSs and no splicing graphs. The process ends then. When the process determines (at 3445) that all received shapes with no splicing graphs are not colored, the process selects (at 3455) shapes that have the least number of CSSs. That is, the process selects the shapes with the least number of CSSs among the received shapes that have no splicing graphs and have no CSSs that have an assigned color. The process then determines (at 3465) whether one such shape is selected. If so, the process is done with selection of a shape and the process ends. Otherwise, the process proceeds to 3470 to select a shape based on a non-tying criterion. That is, the process selects (at 3470) a shape among the received shapes that has (1) no splicing graphs, (2) no CSSs that have an assigned color, and (3) the least number of CSSs. When the process determines (at 3420) that there are two more received shapes that have a splicing graph, the process selects shapes with least number of splicing graphs. That is, the process selects shapes that have assigned colors that alternate the least number of times. The process then determines (at 3440) whether one such shape is selected. If so, the process is done with selection of a shape and the process ends. Otherwise, the process proceeds to 3450 to select shapes with the least number of CSSs among the received shapes that has least number of splicing graphs. The process 3400 then determines (at 3460) whether only one such shape is selected (i.e., whether there is only one received shape with the least number of splicing graphs that has the least number of CSSs). When only one such shape is selected, the process is done with selection of a shape and the process ends. Otherwise, the process proceeds to 3470 to select a shape based on a non-tying criterion. That is, the process selects (at 3470) a shape among the received shapes with the least number of splicing graphs that have the least number of CSSs). The process 3400 then ends. Finally, the process 2400 outputs (at 2445) the results (i.e., the design layout with one or more splicing graphs that resolve the DP loop violation) as a set of data that is used to produce multiple masks for fabricating the design layout region. FIGS. 35A and 35B illustrate a detailed example of introducing splicing graphs to shapes in a layer of a design layout 3500 in order to resolve a DP loop violation. Specifically, this figure illustrates in fifteen different stages 3551-3565 that a DP loop violation committed by three shapes 3502, 3503, and 3504 is resolved by introducing a splicing graph in shape 3504. The design layout 3500 includes shapes 3501-3506. Stage 3551 shows that the shapes 3501-3506 do not have assigned colors. In some cases, no colors have been assigned to these six shapes. In other cases, the colors are unassigned from these six shapes. These six shapes belong to a defined group because these shapes include three DP loop-forming shapes 3502-3504 and the shapes 3501, 3505, and 3506 that are associated with the DP loop-forming shapes. Stage 3552 shows that CSSs are determined and marked. These CSSs are also associated and linked based on their relationships. These associations between these CSSs are shown through the use of the links 3514. As shown, the shapes 3501-3506 include fourteen identified CSSs 3515-3528, and six associated sets of CSSs. Stage 3553 shows the six associated sets 3531-3536. Also shown in stage 3553, the first shape 3501 (i.e. the shape with the fewest CSSs) has its single CSS 3515 colored red (i.e., it is assigned to the red exposure). For the purpose of description, it is assumed that red and green are the two colors available to assign to shapes in the design layout. In some embodiments this assignment is a random choice, and in some embodiments there is a default color. The shape 3501 is the first shape selected to have an assigned color because this shape has the least number of links (e.g., 1) among the six shapes 3501-3506 in the group. Stage 3554 shows that CSS 3516 is colored next. This is because CSS 3516 is associated with CSS 3515 (i.e., CSS 3516 is in the same CSS sub-graph (not shown) as CSS 3515). At Stage 3554, coloring the shape 3501 is done because all CSSs of the shape as well as all CSSs associated with the CSSs of the shape 3501 have an assigned color. The next shape to be colored is the shape 3502 because it is the only partially colored shape among the remaining shapes to be colored. Stage 3555 shows that CSS 3517 is next colored. This is because CSS 3517 is next to CSS 3516 that has already been colored within the shape being colored (i.e., the shape 3502). As shown, CSS 3517 is colored green because it is the color that is assigned to CSS 3516. As described above, some embodiments assign the same color to CSSs in one shape to avoid introducing splicing graphs whenever possible. Next, stage 3556 shows that CSS 3520 is colored next because CSS 3520 is associated with CSS 3517. CSS 3520 is colored red because the neighboring CSS 317 has been colored green. Stage 3557 shows that CSS 3518 is colored next because it is the remaining CSS of the shape 3502 that is being colored. CSS 3518 is colored green, which is the same color that is assigned to the other CSSs (i.e., CSSs 3516 and 3517). Stage 3558 shows that CSS 3523 is colored next because CSS 3523 is associated with CSS 3518 of the shape 3502 that is being colored. At stage 3558, coloring the shape 3502 is done because all CSSs of the shape as well as all CSSs associated with the CSSs of the shape 3502 have an assigned color. The next shape to be colored is the shape 3503 because the shape 3503 is one of two partially colored shapes (i.e., the shapes 3503 and 3504) among the remaining shapes to be colored and the shape 3503 has less number (i.e., 2) of CSSs than the shape 3504 does (i.e., 3). Stage 3559 shows that CSS 3519 is colored next because it is the remaining CSS of the shape 3503 that is being colored. CSS 3519 is colored red which is the same color assigned to the CSS 3520 of the same shape 3503. Stage 3560 shows that CSSs 3521, 3524, and 3527 are colored next because these three CSSs are associated with CSS 3519 of the shape 3503 that is being colored. CSSs 3521, 3524, and 3527 are colored green, red, and green, respectively, because these three CSSs and CSS 3519 are neighboring CSSs that have to alternate colors. At stage 3560, coloring the shape 3503 is done because all CSSs of the shape as well as all CSSs associated with the CSSs of the shape 3503 have an assigned color. There remain three shapes to be colored. They are the shapes 3504, 3505, and 3506. The shape 3504 has a splicing graph already because it has two different colors assigned to two of the CSSs it includes. The shape 3505 has three CSSs while the shape 3506 has two CSSs. Therefore, the next shape to be colored is the shape 3506. Stage 3561 shows that CSS 3528 is colored next because CSS 3528 is the remaining CSS of the shape 3506 that is being colored. CSS 3528 is colored green which is the same color assigned to the CSS 3527 of the same shape 3506. Stage 3562 shows that CSS 3526 is colored next because CSS 3526 is associated with CSS 3528 of the shape 3506 that is being colored. CSS 3526 is colored red because the neighboring CSS 3528 has been colored green. At stage 35062, coloring the shape 3506 is done because all CSSs of the shape as well as all CSSs associated with the CSSs of the shape 3506 have an assigned color. The remaining two shapes to be colored are the shapes 3504 and 3505. The next shape to be colored is the shape 3505 because the shape 3504 already has a splicing graph and the shape 3505 does not. Stage 3563 shows that CSS 3525 is colored next because CSS 3525 is the remaining CSS of the shape 3505 that is being colored. CSS 3525 is colored red because the other CSSs (i.e., CSSs 3524 and 3526) of the same shape 3505 are colored red. Stage 3564 shows that CSS 3522 is colored next because CSS 3522 is associated with CSS 3525 of the shape 3505 that is being colored. CSS 3522 is colored green because the neighboring CSS 3525 is colored red. At stage 3563, coloring the shape 3505 is done because all CSSs of the shape as well as all CSSs associated with the CSSs of the shape 3505 have an assigned color. Moreover, since all CSSs of all shapes including shape 3504 are colored, the coloring process for this group of six shapes is completed. As a result, one splicing graph 3570 is introduced in the shape 3504 between CSSs at stage 3565. As shown, the splicing graph 3570 is a straight line. However, the splicing graph may also be non-straight line based on which the shape 3504 is divided. FIG. 36 illustrates the result of coloring the design layout 3500 from FIGS. 35A-B for resolving the DP loop violation the design layout has. As described above, the shape 3504 is to be split between two exposures. FIG. 36 also illustrates resulted data defining two mask layouts 3605 and 3610 for fabricating the design layout 3500. Mask layout 3605 defines the first (red) exposure, and includes a shape 3625 that makes up part of the shape 3504. Mask layout 3610 defines the second (green) exposure, and includes a shape 3630 that makes up the remaining part of the shape 3504. In other words, mask layout shapes 3625 and 3630 collectively define the design layout shape 3504. Lastly, FIG. 36 illustrates a region of a fabricated IC corresponding to design layout region 3504. Mask layout shapes 3625 and 3630 are printed in different exposures so as to form shape 3635 on the fabricated IC. Shape 3635 includes the splicing graph 3570 around which the two portions of shape 3635 that are printed in different exposures overlap. FIG. 37 conceptually illustrates an example architecture of a design decomposer 3700 of some embodiments that resolves DP loop violation by introducing a minimal number of splicing graphs to the shapes. In some embodiments, the design decomposer 3700 is a stand-alone application, while in other embodiments the design decomposer might be integrated into another application, and in yet other embodiments the design decomposer might be implemented within an operating system. The design decomposer 3700 is similar to the design decomposer 900 described above by reference to FIG. 9 except the design decomposer 3700 has several additional components and features of some common components that are different. FIG. 37 also illustrates the design layouts repository 905 and the design rules repository 935 described above by reference to FIG. 9. The design decomposer 3700 includes the design rule checker 915, the splicing graph minimizer 925, and the coloring engine 930. In addition, the design decomposer 3700 includes a layer selector 3725, a graph generator 3735, a graph storage 3715, and an interface 3740. As described above, the design layout repository 905 stores one or more sets of IC layout data (e.g., a set of data which defines a number of shapes which will be fabricated on a number of layers of an IC). In some embodiments, the design decomposer 3700 receives an IC layout from the design layout repository 905. In other embodiments, the layout may be received from a different database or a different type of storage element. The IC layout data is received by a layer selector 3725, which in some embodiments selects a single layer of the IC layout to process. The layer selector 3725 provides the selected layer data to the design rule checker 935 in some embodiments. The design rule checker 935 receives the selected layer data from the layer selector 3725 and a set of manufacturing constraints (e.g., design rules) from the design rules repository 935. In some embodiments, the set of manufacturing constraints may include a pitch requirement (e.g., minimum same color spacing rule), grid placement constraints, edge placement constraints, etc. The design rule checker 915 of some embodiments determines the CSSs of the received layer of the IC. In some embodiments, the design rule checker also associates the identified CSSs with a shape (e.g., the shape that includes the particular CSS). The design rule checker 915 passes the identified and associated CSS data to the graph generator 3735 and/or to the splicing graph minimizer 925. In some embodiments, the graph generator is used to draw a line graph (e.g., a CSS graph or a shape graph). In addition, the graph generator may be used to partition the CSS graph into sub-graphs. The graph generator 3735, in addition to receiving data from the design rule checker 915, may also receive data from a graph storage element 3715. The graph generator of some embodiments passes its output to the graph storage element for use during later stages of the coloring process. The graph generator 3735 of some embodiments also passes its output to the interface 3740 and/or the splicing graph minimizer 925. In some embodiments, the graph generator 3735 identifies that a DP loop violation contained in the design layout is not resolvable by introducing splicing graphs. The interface 3740 identifies and reports unresolvable DP loop violations to a user. In some embodiments, the interface identifies unresolvable DP loop violations based on shape graphs received from the graph generator 3735, while in other embodiments the interface simply reports the information about the unresolvable DP loop violation received from the graph generator. In some embodiments, the interface 3740 sends the design layout (or reference thereto) containing the unresolvable DP loop violation to another module (not shown) which resolves a DP loop violation by moving shapes in the design layout as described in Section II above. The splicing graph minimizer 925 introduces splicing graphs in the shapes in the layer of the design layout that contains the DP loop violation. The splicing graph minimizer 925 receives or retrieves shapes, shape graphs, CSSs, CSS graphs, sub-graphs, etc. from the design rule checker 915, the graph generator 3735, and/or the graph storage 3715. The splicing minimizer 925 of some embodiments minimizes the number of splicing graphs it introduces by performing the process 33 described above by reference to FIG. 33. The coloring engine 930 colors the shapes according to the colors assigned to the shapes by the splicing graph minimizer 925. That is, the coloring engine 930 modifies the layer of the design layout and deposits in the design layouts repository 905. While many of the features have been described as being performed by one module (e.g., the graph generator 3735), one of ordinary skill would recognize that a particular operation might be split up into multiple modules, and the performance of one feature might even require multiple modules in some embodiments. Many of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer readable storage medium (also referred to as computer readable medium). When these instructions are executed by one or more processing unit(s) (e.g., one or more processors, cores of processors, or other processing units), they cause the processing unit(s) to perform the actions indicated in the instructions. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, RAM chips, hard drives, EPROMs, etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections. In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage, which can be read into memory for processing by a processor. Also, in some embodiments, multiple software inventions can be implemented as sub-parts of a larger program while remaining distinct software inventions. In some embodiments, multiple software inventions can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software invention described here is within the scope of the invention. In some embodiments, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs. FIG. 38 conceptually illustrates an electronic system 3800 with which some embodiments of the invention are implemented. The electronic system 3800 can be used to execute any of the control, virtualization, or operating system applications described above. The electronic system 3800 may be a computer (e.g., a desktop computer, personal computer, tablet computer, server computer, mainframe, a blade computer etc.), phone, PDA, or any other sort of electronic device. Such an electronic system includes various types of computer readable media and interfaces for various other types of computer readable media. Electronic system 3800 includes a bus 3805, processing unit(s) 3810, a system memory 3825, a read-only memory 3830, a permanent storage device 3835, input devices 3840, and output devices 3845. The bus 3805 collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system 3800. For instance, the bus 3805 communicatively connects the processing unit(s) 3810 with the read-only memory 3830, the system memory 3825, and the permanent storage device 3835. From these various memory units, the processing unit(s) 3810 retrieve instructions to execute and data to process in order to execute the processes of the invention. The processing unit(s) may be a single processor or a multi-core processor in different embodiments. The read-only-memory (ROM) 3830 stores static data and instructions that are needed by the processing unit(s) 3810 and other modules of the electronic system. The permanent storage device 3835, on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when the electronic system 3800 is off. Some embodiments of the invention use a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) as the permanent storage device 3835. Other embodiments use a removable storage device (such as a floppy disk, flash drive, etc.) as the permanent storage device. Like the permanent storage device 3835, the system memory 3825 is a read-and-write memory device. However, unlike storage device 3835, the system memory is a volatile read-and-write memory, such a random access memory. The system memory stores some of the instructions and data that the processor needs at runtime. In some embodiments, the invention's processes are stored in the system memory 3825, the permanent storage device 3835, and/or the read-only memory 3830. For example, the various memory units include instructions for processing multimedia clips in accordance with some embodiments. From these various memory units, the processing unit(s) 3810 retrieve instructions to execute and data to process in order to execute the processes of some embodiments. The bus 3805 also connects to the input and output devices 3840 and 3845. The input devices enable the user to communicate information and select commands to the electronic system. The input devices 3840 include alphanumeric keyboards and pointing devices (also called “cursor control devices”). The output devices 3845 display images generated by the electronic system. The output devices include printers and display devices, such as cathode ray tubes (CRT) or liquid crystal displays (LCD). Some embodiments include devices such as a touchscreen that function as both input and output devices. Finally, as shown in FIG. 38, bus 3805 also couples electronic system 3800 to a network 3865 through a network adapter (not shown). In this manner, the computer can be a part of a network of computers (such as a local area network (“LAN”), a wide area network (“WAN”), or an Intranet, or a network of networks, such as the Internet. Any or all components of electronic system 3800 may be used in conjunction with the invention. Some embodiments include electronic components, such as microprocessors, storage and memory that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM), recordable compact discs (CD-R), rewritable compact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), magnetic and/or solid state hard drives, read-only and recordable Blu-Ray® discs, ultra density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media may store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter. While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some embodiments are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some embodiments, such integrated circuits execute instructions that are stored on the circuit itself. As used in this specification, the terms “computer”, “server”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms display or displaying means displaying on an electronic device. As used in this specification, the terms “computer readable medium,” “computer readable media,” and “machine readable medium” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral signals. While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. For example, while the examples shown illustrate splitting one or more shapes of a design layout region into two exposures, one of ordinary skill in the art would recognize that some embodiments would use similar processes to split shapes of a design layout region into more than two (e.g., three, four, etc.) exposures. One of ordinary skill in the art will also recognize that in some instances above, when referring to assigning shapes or portions of shapes to multiple exposures, the shapes (or portions thereof) are actually assigned to multiple mask layouts that are used to create multiple masks that enable a design layout layer to be printed in multiple exposures. Similarly, one of ordinary skill would recognize that while many instances above refer to “drawing” a graph, some embodiments do not actually draw the visible graph, but instead define the graph as a data structure. In addition, a number of the figures (including FIGS. 8, 10, 11, 14, 15, 17, 19, 22, 24, 30, 26, 33, and 34) conceptually illustrate processes. The specific operations of these processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. Thus, one of ordinary skill in the art would understand that the invention is not to be limited by the foregoing illustrative details.
053012143	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an apparatus for loading fuel rods into a fuel assembly for use in a nuclear reactor, such as a pressurized water reactor or the like. 2. Technical Background of the Invention A conventional fuel assembly such as the one disclosed in U.S. Pat. No. 5,068,081, shown in FIG. 10, is known. In this figure, the numerals 1 and 2 refer to top and bottom nozzles, respectively, which are disposed vertically and oppositely spaced apart, and have a plurality of rigidly fixed control-rod guide pipes 3 (hereinbelow referred to as guide pipes 3) between the top nozzle 1 and the bottom nozzle 2. In the mid section of the guide pipes 3 are a plurality of grids 4 disposed vertically and spaced apart from each other. The grids 4 are constructed of a plurality of straps 7 made of thin metal strips having slits 8 formed in the longitudinal direction, as shown in FIG. 4. The slits 8 are interlocked to form a latticed structure as shown in FIG. 5, and each space bounded by the straps is known as a grid cell 5. Each grid cell 5 is provided with dimples 9 and springs 10 formed on the opposing walls of the grid cells 5. A fuel rod 6 inserted into a grid cell 5, shown in FIG. 6, is pressed against the dimple 9 by the spring 10, thereby holding the fuel rod 6 firmly in the grid cell 5. There are different approaches to the steps involved in assembling such an assembly. For example, in the first method, as shown in FIG. 1, the grids 4 are disposed at a predetermined spacing, and the guide pipes 3 and an instrumentation tube is inserted into and fixed to designated grid cells 5 of each of the grids 4, respectively, followed by insertion of the fuel rods 6 into the other grids cells 5 of each of the grids 4 which are supported by the guide pipes 3. In the second method, the fuel rods 6 are inserted into and firmly held in the grid cells 5 first, followed by insertion of the control-rod guide pipes 3 and an instrumentation tube into the other grid cells 5 of the grids 4, followed by a step of rigidly fixing the guide pipes 3 to the grids. A method of inserting fuel rods 6 in grid cells 5 with the use of a pull-in loader is known, for example, in Japanese Patent Application, Laid open publication, H2-181,699, which involves the use of key means to deactivate the springs 10, followed by extending the pull-in rods of a pull-in device through the grids 5, gripping the tips of the fuel rods 6 housed in a fuel rod magazine with the gripping device attached to the pull-in rods, and loading the fuel assembly with fuel rods 6 by pulling the fuel rods 6 into the grid cells 5 of the grids 4. There are problems in loading the fuel rods 6 with the use of pull-in rods after the guide pipes 3 (and an instrumentation tube) are fixed to the grids 4. One of the problems is the mechanical interference which occurs between the pull-in rods and the installed guide pipes 3 when trying to load the fuel rods 6 into the grids 4. The mechanical interference is due to the fact that certain grid cells 5 are already occupied by the cylindrical insert parts of the guide pipes 3 disposed at the entrance to the grids. In such a system, those pull-in rods corresponding with the grid cells 5 occupied by the guide pipes 3 must not be activated, and only those pull-in rods which correspond with the fuel rods 6 to be pulled into the grid cells 5 should be activated. The result is that the loading mechanism becomes complex because of the need for a special control device to select the correct pull-in rods. Furthermore, because the arrangement of the guide pipes in the grids are different for each tier of grid cells, the operation of the pull-in rods must be adjusted for each tier of grid cells, leading to a lengthy and cumbersome fuel rod installation operation. SUMMARY OF THE PRESENT INVENTION The present invention was made in view of the problems in the conventional fuel rod loading devices of the pull-in rod type, and an objective of the invention is to present a loading apparatus of the pull-in rod type having a simple mechanical construction and operates efficiently and quickly to load the fuel rods into the fuel assembly, without the necessity for having a special selection device. The assembling apparatus of the present invention comprises, from the fuel rod entry-side of the assembling apparatus: (a) a fuel rod magazine aligned about a central axis and disposed on the entry-side end of the apparatus, for housing fuel rods extending longitudinally in parallel alignment; (b) support frames aligned about the central axis, for supporting the grids so that the grid cells face in the direction of longitudinally extending fuel rods; and (c) a pull-in loader for loading fuel rods, aligned about the central axis and freely rotatably disposed on the exit-side end of the apparatus opposite to the fuel rod magazine, the pull-in loader having: a plurality of pull-in rods provided with gripping means attached to the end thereof for gripping and loading the fuel rods in the fuel assembly, wherein (d) the pipe-cells, for inserting the control rod guide pipes, are situated in the lattice structure of the grid, so that the locations of pipe-cells in one quadrant of the grids correspond with the locations of pipe-cells in the remaining three quadrants when the one quadrant is rotated in steps of ninety degrees about the central axis of the grids; and (e) the pull-in loader is provided with: a plurality of pull-in rods, of a length sufficient to reach the entry-side end of the fuel rods by translating longitudinally along the central axis, aligned and corresponded with the locations of the fuel-rod-cells for firmly holding the fuel rods therein. According to the assembling apparatus of the present invention, it is possible to load one quarter of all the fuel rods required for the fuel assembly in one loading operation, simply by inserting the pull-in rods into the fuel rod magazine and after gripping the ends of the fuel rods, loading the fuel rods into the grid cells by retracting the pull-in rods back into the loader. In the above sequence of steps, there is no need to select the pull-in rods to be activated, every time the loader is rotated 90 degrees about the central axis for loading, so as to avoid those grid cells which are occupied by the guide pipes because the pull-in rods are already disposed to correspond with those grid cells which are intended for the fuel rods. 90 After one quarter of the required rods are loaded into the fuel assembly, the pull-in loader is rotated through 90 degrees, and the loading sequence of the pull-in rods is repeated to load the fuel rods into the next quadrant of the grids. Repeating the above steps for the remaining two quadrants of the grid, all the fuel rods are loaded into the fuel assembly. Such a simplified loading operation is made possible by duplicating the assigned locations of the pipe-cells in one quadrant of a grid exactly for the remaining three quadrants, so that for every 90 degree rotation of the pull-in loader, the pull-in rods are arranged to correspond with the grid cells assigned for the fuel rods in the grid, thus inserting the fuel rods into only the grid cells assigned for the fuel rods. The invented loading apparatus thus simplifies the loading process by not requiring the use of a pull-in rod selector which is needed in the conventional pull-in rod type fuel rod loaders.
051014220	claims	1. Apparatus for guiding X-rays, comprising: a glass capillary having an outer surface and a tapered, elongated bore having a relatively large first end and a relatively small second end, the bore being defined by a thin glass wall; cladding means on at least a part of the outer surface of said capillary for strengthening the glass wall thereof; support means for at least one end of said capillary, said support means including mounting means and adhesive means fastening said mounting means to said outer surface of said capillary and to said cladding means; and means for applying tension to said capillary. 2. The apparatus of claim 1, said apparatus further including means introducing helium into said capillary bore. 3. The apparatus of claim 1, wherein said support means includes a mounting block for each end of said capillary, and adhesive means securing a first mounting block to a first end of said capillary and a second mounting block to a second end of said capillary, said adhesive means connecting each block to the outer surface of the capillary and to the cladding at corresponding ends thereof. 4. The apparatus of claim 3, wherein said support means includes means for moving one of said mounting blocks with respect to the other for applying tension to said capillary. 5. The apparatus of claim 4, wherein each said mounting block includes means for receiving a corresponding end portion of said capillary, for receiving at least an end portion of said cladding means, and for receiving said adhesive means for securing said capillary and said cladding means to said mounting block. 6. The apparatus of claim 5, further including gimbal means for said mounting blocks. 7. The apparatus of claim 5, further including means securing said mounting blocks for relative motion to apply tension to said capillary along a longitudinal axis thereof. 8. The apparatus of claim 7, further including adjustable means for aligning the end portions of said capillary with the longitudinal axis of the capillary. 9. The apparatus of claim 8, wherein said adjustable means comprises gimbal means for said mounting blocks. 10. The apparatus of claim 5, wherein each said mounting block includes an aperture for receiving a corresponding end portion of said capillary, the ends of said capillary extending through said apertures. 11. The apparatus of claim 10, wherein said cladding means is a plastic coating on said capillary, said coating extending substantially the entire length of said capillary and extending into, but not completely through, the corresponding apertures. 12. The apparatus of claim 11, wherein said adhesive means is located within said apertures to engage the end portions of said capillary and said cladding means. 13. The apparatus of claim 12, wherein said mounting blocks are adjustable to align the end portions of said capillary. 14. The apparatus of claim 13, further including gimbal means for said mounting blocks. 15. The apparatus of claim 14, further including means for introducing helium into said capillary bore under pressure to produce a slow flow of helium therethrough.
051736128	description	DETAILED DESCRIPTION OF THE EMBODIMENTS An example of this invention will now be explained by referring FIG. 1 and FIG. 2. A flat, circular X-ray transparent film (1) is made from diamond. A ring substrate (3) is a substrate, e.g. silicon substrate, on which the diamond film is grown. Reinforcing crosspieces (2) made from diamond are fabricated on the diamond X-ray transparent film (1). An opening through which X-rays pass is perforated at the center of the substrate (3). Namely, the substrate (3) is partially etched away except the periphery. Thus it is called a ring substrate. A supporter ring (4) is stuck to the periphery of the ring substrate (3). In the example, the reinforcing crosspieces (3) are fabricated only on the central part of the X-ray transparent film (1). The periphery of the reinforcing diamond film is a flat film without holes or grooves. In comparison with the window shown in FIG. 3, an additional diamond film for reinforcing is deposited on the surface of the transparent form opposite to the silicon substrate. The reinforcing diamond film is partially etched to shape the reinforcing crosspieces at the center. The reinforcing diamond film is thicker than the diamond X-ray transparent film. In the embodiment, the reinforcing crosspieces are vertically-continuing parallel ones. In this embodiment, the supporter ring (4) is stuck to the rear surface of the silicon substrate (3). Alternatively the supporter ring (4) may be stick to the front surface of the reinforcing diamond film containing the crosspieces (2). Furthermore in the embodiment, the reinforcing crosspieces (2) and the substrate (3) sandwich the X-ray transparent film (1) therebetween. But other versions will be allowed. The diamond reinforcing crosspieces (2) may be formed on the rear surface of the diamond X-ray transparent film (1) in the opening (8) of the substrate (3). Regarding the patterns of the crosspieces, lattice patterns with members parallel in two directions; lengthwise and crosswise, or a repetition of regular polygons will be allowable instead of the single-parallel patterns. The thickness of the diamond X-ray transparent film (1) is preferably 0.05 .mu.m to 10 .mu.m. The thickness of the diamond reinforcing crosspieces (2) should be thicker than that of the transparent film (1) for reinforcing the transparent film (1) effectively, concrete thicknesses of the diamond transparent film (1) and the diamond reinforcing film containing the crosspieces should be determined by considering the X-ray transmittance required for the windows and the forces which will act on the mask. The substrate is dispensable for the X-ray window, although it is necessary to deposit a diamond film thereupon at the first stage of fabrication. It is possible to etch away whole of the substrate without losing mechanical strength for an X-ray window by determing the width, the height and the spacing of the crosspieces appropriately. The embodiment without the substrate is shown in FIG. 4. In comparison with the first embodiment shown in FIG. 1, the silicon substrate (3) has been completely eliminated, and a supporter ring (4) has been directly glued to the periphery of a diamond X-ray transparent film (1). This window has a diamond reinforcing crosspieces (2), the X-ray transparent film (1) and the supporter ring (4) from top to bottom. Alternatively, the supporter ring (4) can be stick to the periphery of the reinforcing diamond film. In any embodiments, the substrate (3) is a substrate on which diamond is grown. Thus, the material of the substrate must resist against the temperature higher than 400.degree. C. which the diamond synthesis requires. Besides the high heat resistance, the substrate must easily be etched away, because whole of or parts of the substrate will be etched after the growth of diamond thereon. To satisfy these requirements, the substrate is preferably made from semiconductors, e.g. silicon (Si), germanium (Ge) or gallium arsenide (GaAs) or high melting point metals, e.g. molybdenum (Mo) or tungsten (W). The surface of the substrate on which diamond will grow is mirror-polished to satisfy the requirement of flatness. However, it is more preferable to prepolish the raw substrate by diamond powder with diameters shorter than 10 .mu.m. The advantages of this invention are now explained. Both the X-ray transparent film and the crosspieces are made from diamond in the X-ray window of the invention. Change of temperature induces no thermal stress between the X-ray transparent film and the crosspieces, because of the same thermal expansion coefficient. Thus this mask enjoys good flatness. The X-ray transparent film is made from diamond which inherently excels in strength and is still reinforced by a lot of crosspieces. The window will be able to hold sufficient strength even if the X-ray transparent film is thinner than 1 .mu.m. The transmittance of this mask is far higher than the conventional beryllium window, because diamond is inherently more transparent to X-rays than beryllium and the mask of this invention is thinner than the beryllium window. As mentioned before, the thickness of the crosspieces is bigger than that of the X-ray transparent film. However, the crosspieces can be as thin as a few micrometers. X-rays can pass through such thin crosspieces without significant energy loss. The intensity of X-rays which are transmitted through the window is big enough, because of the high transmittance which is defined as the product of thickness and transparency. The high transmittance of the window will contribute to rising the sensitivity of X-ray detectors. Regarding the thermal stress, a little thermal stress will be induced by change of temperature in the window shown in FIG. 1 and FIG. 2, because the silicon substrate remains partially. But the embodiment of FIG. 4 is perfectly immune from the problem of thermal stress, because the silicon substrate has been completely removed. The method of producing the X-ray window will now been explained by referring to FIG. 5. (a) A flat substrate, e.g. silicon (Si), germanium (Ge), gallium arsenide (GaAs), molybdenum (Mo) and tungsten (W) is mirror-polished. PA0 (b) A diamond film is grown on the substrate (3) by a vapor phase synthesis method. The diamond film becomes the X-ray transparent film (1). The vapor phase synthesis method is a method comprising the steps of supplying a material gas, e.g. methane and a carrier gas, e.g. hydrogen on a heated substrate, exciting the gases by some means to induce vapor phase reaction and depositing the material borne by the reaction on the substrate. There are some variations with different means for excitation of gases in the vapor phase synthesis methods. PA0 (c) A diamond-growth-inhibiting mask (5) having holes at the positions where crosspieces will be shaped is deposited on the central part of either surface of the X-ray transparent film (1). The diamond-growth-inhibiting mask is fabricated by evaporating tungsten (W), molybdenum (Mo), silicon (Si), germanium (Ge), nickel (Ni), chromiun (Cr) or titanium (Ti) on whole surface of the X-ray transparent film (1) and eliminating, by photolithography, the material at the positions where crosspieces will be shaped. Alternatively a similar mask may be prepared by setting on the film (1) a metal mask having holes with the same pattern of the crosspieces and evaporating the material mentioned above on the film covered with the metal mask. The material is deposited only on the positions which are not covered with the mask metal. The deposited material forms an equivalent diamond-growth-inhibiting mask. PA0 (d) Diamond is grown on the surface covered with the diamond-growth-inhibiting mask (5) by a vapor phase synthesis method. No diamond growth occurs on the material of the mask. Anisotropic diamond growth continues at the holes of the mask beyond the height of the mask (5). The second diamond film is called a reinforcing film. The selective growth of diamond by using the diamond-growth-inhibiting mask was proposed by Japanese Patent Laying Open No. 1-123423. PA0 (e) The diamond-growth-inhibiting mask (5) is etched away by acid or alkali. Crosspieces and a peripheral part of the reinforcing film remain. The peripheral part of the rear surface and the side of the substrate (3) is covered by photoresist (6). Only the central part of the substrate (3) is uncovered. Instead of the photoresist, the same part of the substrate may be otherwise covered by a diamond layer deposited by selective growth of diamond. PA0 (f) The central part of the substrate is eliminated by dry etching or wet etching. PA0 (g) The photoresist (6) is eliminated. A supporter ring (4) is fitted to the periphery of the substrate (3). Thermal CVD (chemical vapor deposition) method (Japanese Patent Laying Open No. 58-91100), plasma CVD method (Japanese Patent Laying Open No. 58-135117, No. 58-110494), ion beam method, laser CVD method, and burner flame method have so far been proposed for synthesizing diamond. Among these vapor phase synthesis methods, the thermal CVD method or the plasma CVD method is appropriate for producing the X-ray transparent film and the crosspieces of this invention because of the uniformity of diamond growth. The diamond X-ray transparent film should be 0.05 .mu.m to 10 .mu.m as explained before. Within the range, the concrete thickness of the diamond film should properly be determined by considering the scope of the wavelength of X-rays, the necessary transmittance for X-rays, and the required mechanical strength. In this example, the diamond-growth-inhibiting mask is formed on the side opposite to the substrate (3). Alternatively the diamond-growth-inhibiting mask can be formed also on the side of the substrate (3). In the version, the central part of the substrate (3) is eliminated and a diamond-growth-inhibiting mask shall be formed by the method similar to the former example. Thus, the X-ray window of this invention is produced by the steps above. So far the material of the film (1) and the crosspieces (2) have been called "diamond". Here the definition of "diamond" of this invention must be clarified. "Diamond" is such a material mainly consisting of carbon in which the existence of crystalline diamond is confirmed by the X-ray diffraction method, the electron beam diffraction method or the Raman scattering spectrometry. Inclusion of non-diamond carbon, e.g. graphite, amorphous carbon, or quasi-diamond carbon is allowable. The "diamond" is also allowed to include small amount of non-carbon materials, e.g. boron (B), nitride (N), oxygen (O), aluminum (Al), silicon (Si), phosphor (P), titanium (Ti), tungsten (W), tantalum (Ta), iron (Fe), nickel (Ni) as impurities. Especially, the inclusion of boron (B) less than 1000 ppm will convert an insulating diamond to a semiconductor diamond by supplying positive holes. The conversion by boron lowers the electric resistance and suppresses the occurrence of electrification (or charge-up) of the mask when it is irradiated by X-rays. EMBODIMENTS More concrete method for producing the X-ray windows of this invention is now explained. Silicon wafers with the diameter of 15 mm.phi. to 0.3 m.phi. (300 mm.phi.) were used as a substrate on which diamond is grown. Here, an example of a 15 mm.phi. wafer is described. A diamond film was grown up to 0.3 .mu.m of thickness on either of surface of the silicon wafer by the microwave plasma CVD method using the mixture of methane gas (CH.sub.4) and hydrogen gas (H.sub.2) as a material gas. This film was confirmed to be crystalline diamond having a 1333 cm.sup.-1 peak in the Raman scattering by the Raman scattering spectrometry. Molybdenum was evaporated on the diamond film covered with a metal mask having the same patterns as the crosspieces to be produced. Since molybdenum was deposited only on the positions which are not covered with the mask metal, the deposited molybdenum becomes a diamond-growth-inhibiting mask having grooves of 15 .mu.m width separated each other by 50 .mu.m spacing. Diamond was again grown up to the thickness of 20 .mu.m on the first diamond film (1) partially covered with the diamond-growth-inhibiting mask (5) by the microwave plasma CVD method same as the former growth. After the second diamond film had deposited on the first diamond film, the diamond-growth-inhibiting mask (5) was etched away by a solution of potassium hydroxide. A lot of parallel crosspieces with a 15 .mu.m width and a 20 .mu.m height separating each other by a 50 .mu.m spacing remain. The peripheral part of the rear surface and the side of the silicon substrate were covered with photoresist (6). The central part of a diameter of 7 mm.phi. of the silicon substrate was solved away by fluoric-nitric acid. The specimen having the substrate, the diamond transparent film and the crosspieces was fixed to an aluminum supporter ring (4). The X-ray windows shown in FIG. 1 and FIG. 2 were obtained. The X-ray window was mounted on an X-ray detector to measure the transmittance performance for nitrogen K.alpha. X-rays. Then output power of the X-rays transmitted through the diamond window was measured. Then, an open window having a silicon substrate with a 7 mm.phi. hole without diamond film was also mounted on the same X-ray detector instead of the diamond window. Then, output power of the X-rays transmitted through the open window, namely through only air, was also measured. The output power of the former case (through the diamond film) is about 6% of that of the latter case (through air). Although the energy loss attained to 94% of the input power, the transmittance of the diamond window of this invention was sufficiently high, because conventional windows had transmittances far less than 6% in general. Therefore, the X-ray window of this invention excels in the flatness, the X-ray transmittance and the mechanical strength, because the transparent film and the crosspieces are made from diamond which is intrinsically a strong material highly transparent for X-rays and a change of temperature induces no thermal stress between the transparent film and the crosspieces .
	summary
	description	The present invention relates to a charged particle beam apparatus such as a scanning electron microscope and a scanning ion microscope, particularly to a charged particle beam apparatus using an assist gas including an etching gas. In a scanning charged particle microscope apparatus such as a scanning electron microscope and a scanning ion microscope, an assist gas is sometimes used to deposit a thin film onto a sample, or to control an etching rate. In addition, it is known that by the action of gas, electrical charges on the sample surface are sometimes neutralized. Because the supply amount of an assist gas to the sample surface affects its action, the amount is controlled in various methods. The invention described in Patent Reference 1 adopts a method that controls a valve provided on the front of a gas nozzle for intermittent gas supply (see Japanese Patent No. 3921347). In this invention, the gas concentration is intermittently changed on the sample surface, whereby the invention intends to prevent the resolution of a scanning charged particle microscope from being degraded because of excessive gas. In the charged particle beam apparatus such as a scanning electron microscope and a scanning ion microscope, in feeding an assist gas onto the sample surface, for example, a gas supply amount adjusting device such as a massflow controller is used to adjust a supply amount. At this time, when the action of gas is strong, or when it is expected to effect the action by a very small amount of gas, it is necessary to reduce the supply amount. However, available massflow controllers have limitations in the minimum amount adjustable to regulate the supply amount. For example, a commercially available massflow controller is a device that regulates a flow rate of gas of 10 ml/min at the maximum. However, this massflow controller is unable to set such values that the minimum amount is 0.2 ml/min or below. When these values of the supply amount or below are specified, gas supply is stopped. In addition, in the invention described in Patent Reference 1, although gas can be rarefied, it is unable to feed gas of uniform concentration because the valve provided on the front of the gas nozzle is controlled. An object of the invention is to solve the problem, and to provide a charged particle beam apparatus that feeds a very small amount of gas equal to or below the minimum amount of a gas supply amount adjusting device such as a massflow controller to the vicinity of a position at which a charged particle beam is irradiated. In order to solve the problem, in a charged particle beam apparatus according to the invention, first, the flow rate setting of a gas supply amount adjusting device such as a massflow controller is intermittently controlled, whereby such an average gas supply amount is implemented that the amount is equal to or below the minimum supply amount of the gas supply amount adjusting device. Secondly, the gas flow intermittently controlled is introduced into a diffusion mechanism to reduce variations in gas concentration, whereby a gas of more uniform concentration is fed. The gas flow is intermittently fed from the gas supply amount adjusting device such as a massflow controller having a flow rate setting intermittently controlled, and the gas flow is uniformized by diffusion conducted by the diffusion mechanism, whereby a very small amount of gas with no variations in the flow rate can be fed near the position on the sample surface at which a charged particle beam is irradiated. FIG. 1 shows a charged particle beam apparatus according to an embodiment of the invention. The flow rate of gas stored in a gas reservoir 1 is controlled by a massflow controller (control device) 2 that is a gas supply amount adjusting device, and uniformized by a gas diffusion mechanism 3, and a supply gas 5 is fed from a gas nozzle 4 onto a sample 8. Here, the gas to be fed may be an etching assist gas used to cause chemical changes in the irradiation surface by the reaction of gas with a charged particle beam to generate structural changes at that location, a gas used for deposition, or a gas used to neutralize electrical charges on the sample surface. An ion beam 7 that is irradiated from an FIB (focused ion beam) lens barrel 6 reaches the sample 8 together with the supply gas 5, and acts on the sample surface. In this embodiment, the gas diffusion mechanism 3 is implemented by thickening a part of a pipe that forms a gas flow path so that it is thicker than the other parts. In other words, the gas diffusion mechanism 3 is formed of a gas pipe arrangement 9 made of gas pipes configured to form the gas flow path between the gas diffusion mechanism 3 and the massflow controller 2 and having a pipe or pipe section having a diameter larger than that of the gas nozzle 4. In addition, intermittent control over the gas flow is implemented by intermittent application of the voltage of flow rate regulation control signals for the massflow controller 2. Control over the massflow controller 2 is conducted according to analog voltage. This analog voltage is switched between zero and a specified value. More specifically, data of a control digital-to-analog converter is changed periodically. In this gas supply device, for example, such intermittent control is conducted in repeated cycles in which a gas flow of 0.2 ml/min, which is the minimum supply amount of the massflow controller 2, is fed for 0.1 second and is stopped for 0.9 second, and then a gas supply amount of 0.02 ml/min can be implemented. FIG. 2 shows a conceptual diagram depicting a manner that gas from the gas supply device according to the invention is uniformized while the gas is passing through the diffusion mechanism. The vertical axis shown in FIG. 2 indicates the gas concentration at a certain moment. The horizontal axis indicates the position of the diffusion mechanism; the left side is gas input, and the right side is gas output. Gas intermittently fed from the left side flows through the diffusion mechanism for output from the right side. Because gas is diffused when it has the concentration gradient, as apparent from FIG. 2, the gas is diffused rightward and leftward while the concentration is lowered as the gas flows. Because the gas is intermittently fed, the gas first flows through the diffusion mechanism as a block of gas. Then, this block of gas is gradually mixed with the blocks of gas before and after the block, and finally outputted as a gas flow of a constant concentration. The length of the diffusion mechanism is determined according to the flow rate of gas and the intermittent cycle of gas supply. In the example shown in FIG. 2, when the length is set to the distance or longer through which gas flows for the time period about ten times the intermittent cycle of gas, an almost uniform gas flow is obtained. In addition, when the diffusion mechanism is provided with a diameter larger than that of the other gas flow paths, expansion and compression occur in the gas flow at the inlet and the outlet of the diffusion mechanism, which makes gas concentration more uniform. In addition, when the concentration of the gas flow is made higher than that achievable by intermittent control, it is sufficient that intermittent control is not conducted and the control voltage of the massflow controller 2 is set to a constant value that can achieve a desired concentration. In the embodiment, an example of the focused ion beam apparatus is taken as the charged particle beam apparatus. However, the invention is also applicable to scanning electron microscopes. According to the invention, such a charged particle beam apparatus can be implemented that the apparatus can obtain a very small gas supply amount equal to or below the minimum amount of a gas supply amount adjusting device such as a massflow controller.
	abstract	Disclosed herein is an apparatus suitable for detecting X-ray, comprising: an X-ray absorption layer comprising an electrode; an electronics layer, the electronics layer comprising: a substrate having a first surface and a second surface, an electronics system in or on the substrate, an electric contact on the first surface, and a first via extending from the first surface toward the second surface; wherein the electrode is electrically connected to the electric contact; wherein the electronics system comprises a controller connected in series with and between the electric contact and the first via.
050158643	summary	BACKGROUND OF THE INVENTION Physicians and other medical personnel are frequently exposed to stray radiation during diagnostic, therapeutic or surgical procedures. Exposure to stray radiation over prolonged periods can be dangerous. To shield against radiation it has been the practice for physician, or other personnel, to wear a protective lead apron, as well as a rigid lead glass head shield, which is attached to the upper portion of the apron. As the apron and head shield have a substantial weight, wearing of this equipment for prolonged periods is extremely fatiguing and can cause back pain and vertebral damage. To overcome this problem, it has been proposed, as described in U.S. Pat. No. 4,254,341 to support the lead apron from an overhead dolley, so that the weight of the apron is not supported by the user. However, devices of this type provide limited maneuverability and in many instances, due to the installation of other overhead equipment, it is not possible to mount the supporting dolley in an overhead position. U.S. Pat. No. 4,581,538 describes a radiation shield that includes a rigid radiation shielding window that is suspended from an overhead dolley and a series of flexible strips of radiation shielding material are suspended from the lower edge of the window. Again, devices of this type have limited maneuverability and as the user must part the flexible strips to perform a working operation, it does not give full protection for the body. SUMMARY OF THE INVENTION The invention is directed to an improved mobile radiation shield having particular use for protecting physicians, and other medical personnel, who may be exposed to stray radiation during diagnostic, therapeutic or surgical procedures. The apparatus includes a mobile frame composed of a pair of vertical frame members, and a plurality of caster wheels are associated with the lower portion of each vertical frame member to enable the frame to be readily moved over the ground or terrain. A lead apron is attached to the frame, preferably by Velcro fasteners, and a head piece including a lead glass window is provided with a flexible bib which is removably attached to the upper end of the frame, also by Velcro fasteners. In addition, the frame includes a generally circular thrust bar, which is adapted to encompass the waist of the user, so that the user, by exerting a force against the thrust bar can move the frame over the ground. The thrust bar is cushioned or padded and can be adjusted in diameter to accommodate different waist sizes. To provide a height adjustent, each vertical frame member is composed of a pair of telescopic sections, so that the vertical frame members can be adjusted to readily accommodate different heights. As a further feature, the apparatus can also include a pair of lead shoulder flaps, which are connected together through a connecting strap, and each shoulder flap can be removably attached to the upper end of the frame and serves to protect the shoulders of the user. With the apparatus of the invention, the entire weight of the apron and head piece is supported entirely by the frame. As the user is not required to support the heavy equipment over prolonged periods, fatigue is substantially reduced and vertebral pain and damage is eliminated. The device is fully maneuverable through walking motion of the user. Thus, there is no limit to the maneuverability of the apparatus. As the radiation shield is propelled by the user and does not require power operation, it is a relatively inexpensive device, as compared to prior art devices that required power operation. The radiation shield provides full protection for the user, protecting not only the body and head, but also the shoulders. The shield is fully adjustable. Vertical adjustment is provided for height and an adjustment is also provided for the waist size of the user. The wheels or casters are arranged such that the leading or front edge of the apron extends slightly beyond the wheels, so that the user can move directly against a table or other object without interference from the wheels. Other objects and advantages will appear in the course of the following description.

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