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	description	This application is a US 371 application from PCT/RU2018/000603 filed Sep. 13, 2018, which claims priority to Russian Application No. 2018125716 filed Jul. 12, 2018, the technical disclosures of which are hereby incorporated herein by reference. The group of inventions relates to nuclear energy, in particular, to the treatment of spent ion-exchange resins, and can be used at nuclear power plants or special plants. Ion-exchange resins are widely used at nuclear power plants to ensure the water-chemical mode of the primary and secondary circuits, the post-purification of condensate from evaporation plants and other auxiliary water systems, as well as during decommissioning of nuclear power units. During use, a significant amount of spent, including oily, ion-exchange resins is accumulated, which relate mainly to low- and medium-active liquid waste, which must be treated for their subsequent storage. A known system for the thermal processing of radioactive ion-exchange resin containing a thermoreactor equipped with a heater with loading and unloading units, therein the system contains a water vapor condenser connected by a line to a thermoreactor, a condensate receiver connected by a line to a water vapor condenser, and a vacuum pump, the input of which is connected to a condensate receiver, and its output is connected to the air exhaust line (utility model 121396, IPC G21F 9/28). The disadvantage of the above method of drying spent ion-exchange resins is the low energy efficiency of the process. The nearest analogue of the claimed invention is a utility model “System for drying spent ion-exchange resins” according to the patent of the Russian Federation No. 161811, IPC G21F 9/28. The said system includes a loading unit connected to a pipeline for feeding a mixture of spent ion-exchange resins and transport water and a pipeline for draining transport water, a metering device, a thermoreactor connected to it, equipped with stirrers, an inclined screw located between the loading unit and the metering device, and also a unit docking for unloading treated ion-exchange resins. The water vapor generated during drying of ion-exchange resins is removed through an aerosol filter equipped with heating using a liquid-packed ring vacuum pump. The disadvantage of the closest analogue is the low efficiency of the process and the low bulk factor of the dried ion-exchange resins. The object solved by this group of inventions is to increase efficiency and expand functionality. The technical result achieved by the claimed group of inventions consists in microencapsulation of ion-exchange resins (immobilization of radionuclides inside microcapsules), reducing the volume of discharged ion-exchange resins and preventing their swelling when exposed to moisture. The said technical result relating to the method is achieved due to the fact that in the method for treatment of spent ion-exchange resins for disposal, comprising feeding a mixture of spent ion-exchange resins with transport water to the loading tank, separating the ion-exchange resins from the transport water by settling the mixture and draining the transport water from the loading tank, the subsequent metered feed of ion-exchange resins separated from the transport water into the drying chamber, vacuum drying with simultaneous mixing of the ion-exchange resins in the drying chamber at a temperature not exceeding 90° C. and unloading the treated ion-exchange resin into a transport container, it is proposed that the ion-exchange resins after vacuum drying in the drying chamber are subjected to additional heat treatment in a high-temperature furnace at a temperature of 250-300° C. with simultaneous stirring and vacuum drying, and unloading treated ion-exchange resin in a transport container is carried out after heat treatment in a high temperature furnace. In addition, it is proposed that the mixture of spent ion-exchange resins with transport water in the loading tank be settled for 10-15 minutes. It is also claimed that ion-exchange resins are fed into the drying chamber in batches of 5 to 10 percent of the volume of the drying chamber; after feeding the first portion, ion-exchange resins are vacuum dried to reach a humidity content of 6-8%, then a new portion is fed and the vacuum drying process is repeated until complete filling the drying chamber. In addition, it is claimed that hot air with a temperature of at least 200° C. be additionally charged into a high temperature furnace. It is proposed to carry out the removal and subsequent purification of the resulting gases and water vapor from a high temperature furnace in the process of heat treatment. The said technical result regarding the device is achieved due to the fact that the device for treatment of spent ion-exchange resins for disposal, including a loading tank connected to a pipeline for feeding a mixture of spent ion-exchange resins and transport water and a pipeline for draining transport water, a metering device connected to a drying chamber equipped with stirrers, an inclined feed screw located between the loading tank and the metering device, a vacuum pump connected by a pipe to the drying chamber, a heated gas filter installed on the pipeline between the drying chamber and the vacuum pump and the docking unit for discharging the treated ion exchange resins, is claimed to additionally equip with a high-temperature furnace with stirrers, as well as a feeding device located between the drying chamber and the high-temperature furnace, to equip the high-temperature furnace with a vacuum drying and gas purification system, and to connect the docking unit for unloading ion-exchange resins to the lower part of the high-temperature furnace. In addition, it is proposed that the loading tank be equipped with a transport water level sensor installed in its upper part and an ion-exchange resin level sensor installed below the transport water level sensor at or below the outlet level of the transport water drain pipe, and a metering device be equipped with a resin level sensor installed at the top of it. It is also proposed that the metering device be made in the form of a cylindrical tank. There is proposed a device for treatment of spent ion-exchange resins for disposal to be equipped with an additional feeding device located between the metering device and the drying chamber, and the feeding device and the additional feeding device to be made in the form of an inclined screw. It is also proposed that a high temperature furnace be equipped with an air heater and a temperature controller connected to the high temperature furnace with a pipeline, and an air heater be made in the form of two coaxially arranged cylindrical chambers equipped with electric heaters. The vacuum drying and gas purification system of a high-temperature furnace is proposed to be made of a gas purification filter and an additional vacuum pump connected by a pipeline, acid and alkaline absorbers located between them with circulation pumps and an after-burner, and the gas purification filter and after-burner to be equipped with heating elements. It is proposed to install a vacuum sensor and a humidity sensor on the pipeline between the vacuum pump and the drying chamber. In addition, it is proposed that the docking station be equipped with a bonnet for docking the high temperature furnace and the container lid. The application of a method in which ion-exchange resins after vacuum drying are thermally treated to a state of microencapsulation, leads to the achievement of the said technical result. The claimed group of inventions is illustrated in graphic material, where the figure shows a device for treatment of spent ion-exchange resins for disposal. A device for treatment of spent ion-exchange resins for disposal includes loading tank 1, metering device 2, made in the form of a cylindrical tank, drying chamber 3, connected to metering device 2, equipped with stirrers, and high temperature furnace 4, equipped with stirrers (stirrers are not shown in the figure), connected to drying chamber 3. Loading tank 1 is connected to a pipeline for feeding a mixture of spent ion-exchange resins and transport water and a pipeline for draining the transport water. Inclined feed screw 5 is located between loading tank 1 and metering device 2, feeding device 6 is located between drying chamber 3 and high-temperature furnace 4, and additional feeding device 7 is located between metering device 2 and drying chamber 3. Also, loading tank 1 is equipped with a transport water level sensor installed in its upper part and an ion-exchange resin level sensor installed below the transport water level sensor at or below the outlet level of the transport water drain pipe, and metering device 2 is equipped with a resin level sensor installed at the top of it (sensors are not indicated in the figure). Vacuum pump 8 is connected to drying chamber 3 by a pipe on which humidity sensor 9, heated gas filter 10 and vacuum sensor 11 are installed in succession. The lower part of high temperature furnace 4 is connected to docking unit 12 for unloading the treated ion-exchange resins into container 13. High temperature furnace 4 and docking unit 12 are connected by pipelines to a vacuum drying and gas purification system. The vacuum drying and gas purification system includes gas purification filter 14 and additional vacuum pump 15, connected between them after-burner 16, and alkaline absorber 18 and acid absorber 19 equipped with circulation pumps 17. Alkaline absorber 18 is designed to neutralize the acid components of the exhaust gas, and acid absorber 19 is designed to further purify the gas after alkaline absorber 18. Circulation pumps 17 are designed for continuous irrigation with a solution of cartridges in absorbers 18 and 19. Gas purification filter 14 and after-burner 16 are equipped with heating elements. High temperature furnace 4 is also equipped with pipeline-connected air heater 20 and temperature controller 21, for example a resistance thermal converter. Air heater 20 is made in the form of two coaxially arranged cylindrical chambers, each of which is equipped with an electric heater. Feeding device 6 and additional feeding device 7 are made in the form of an inclined screw. Docking unit 12 comprises a bonnet (not shown in the figure) for docking high temperature furnace 4 and the lid of container 13. The bonnet provides a complete overlap of the holes in the lid of container 13 and eliminates the possibility of discharge of gases and aerosols generated when it is filled. The operation of the device and the method of treatment of spent ion-exchange resins for disposal is as follows. A mixture of spent ion-exchange resins with transport water is fed into loading tank 1 until the sensor of the level of transport water installed in its upper part is triggered. After that, the ion-exchange resins are separated from the transport water in loading tank 1 by settling the mixture for 10-15 minutes, then the transport water is drained and the mixture of spent ion-exchange resins with transport water is re-fed into loading tank 1. The said operation is repeated until the ion-exchange resin level sensor is triggered. After triggering the ion-exchange resin level sensor, transport water is drained and ion-exchange resins are fed into metering device 2 using inclined feed screw 5, until the resin level sensor is triggered. The ion-exchange resins with a humidity content of 50-60% are fed from metering device 2 to drying chamber 3 using additional feeding device 7, it is metered in portions in the amount of 5-10 percent of the volume of drying chamber 3. After feeding the first portion of the ion-exchange resins, vacuuming up to 8 kPa is carried out using vacuum pump 8 and further vacuum drying at a temperature of not more than 90° C. with simultaneous stirring until the ion-exchange resins reach a humidity content of 6-8%. Then, vacuum pump 8 is turned off, after equalizing the pressure with the atmospheric pressure in drying chamber 3, a new portion of ion-exchange resins is fed and the vacuum drying process is repeated until drying chamber 3 is completely filled. In the process of vacuum drying the ion-exchange resins in drying chamber 3, water vapor is purified in heated gas filter 10. Drying chamber 3 is evacuated to increase the drying efficiency of ion-exchange resins, as well as to intensify the drying process with the removal of not only surface but also pore free moisture. The humidity level control in drying chamber 3 is carried out according to the readings of humidity sensor 9, and the vacuum level is controlled according to the readings of vacuum sensor 11. The dried ion-exchange resin is fed from drying chamber 3 by means of feeding device 6 to high temperature furnace 4, in which the ion-exchange resins are heat-treated at a temperature of 250-300° C. with simultaneous stirring and vacuum drying for a period of 200 to 350 minutes, while the ion-exchange resins go into a state of microencapsulation. At the same time, hot air with a temperature of at least 200° C. is charged into the high temperature furnace using air heater 20 in order to prevent thermal damage to high temperature furnace 4 due to the temperature difference between high temperature furnace 4 and air. The temperature of the fed hot air is controlled by temperature controller 21. After heat treatment, the microencapsulated ion-exchange resins are unloaded via docking unit 12 into container 13. Water vapor and gases released during the heat treatment and unloading of ion-exchange resins into container 13 are removed using additional vacuum pump 15, therein the gases are purified of aerosols by gas purification filter 14 and oxidized to higher oxides in after-burner 16, after which they are further purified on absorbers 18 and 19. The claimed group of inventions allows to reduce the volume of unloaded ion-exchange resins by more than 2 times, ensuring their swelling no more than 10% (by translating them into a state of microencapsulation) and preventing the immobilization of radionuclides inside microcapsules.
054209021	summary	CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation of International application Ser. No. PCT/DE91/00733, filed Sep. 17, 1991. SPECIFICATION The invention relates to a fuel assembly having a bundle or cluster of mutually parallel fuel rods each being guided at a plurality of axial positions by a mesh, or mesh opening, of a grid-like spacer and being laterally supported there by a support spring. Fuel assemblies contain a cluster of fuel rods that are parallel to one another and in boiling water reactors they are disposed around a coolant pipe, which typically has a rectangular cross section with flat pipe walls. The cluster is covered at the top and bottom by a plate having openings for the passage of coolant flowing from bottom to top, and in the case of a boiling water reactor is surrounded laterally by a fuel assembly channel, which typically has a rectangular cross section and practically flat channel walls. The lateral spacing of the fuel elements in the cluster is fixed at a plurality of axial positions of the fuel rods by grid-like spacers. Each fuel rod is guided through a mesh of the grid and is laterally supported there by a support spring. Such a spacer is formed by ribs extending transversely to the rods and being aligned parallel to the rods. It is surrounded on the outside by outer peripheral ribs and on the inside, in the case of a boiling water reactor having a central coolant pipe, by inner peripheral ribs. The ribs may be rectilinear and may penetrate one another, producing polygonal grid meshes. However, they may also be constructed as tubes in particular, which are welded together and annularly surround the fuel rods. The ribs typically have tabs on their upper edge, which serve as flow guide surfaces and in particular in the case of the peripheral ribs, face into interstices between adjacent fuel rods. In pressure water reactors, the axial position of the spacers is dictated by fastening them to guide tubes, while in boiling water reactors having coolant pipes, the spacers may be held on the coolant pipe by stops secured to the pipe walls. The stops abut against the upper and lower edges of both the inner peripheral ribs and adjacent inner ribs, to provide an adequate stop surface area. The inner ribs that extend between the fuel rods form bearing surfaces in each mesh for at least one support spring which presses the fuel rod against other retaining elements, such as rigid knobs. For the coolant flowing from bottom to top between the fuel rods, the ribs, knobs and springs present undesirable hindrances that prevent a uniform flow. In order to provide the best possible utilization of the existing cross section, an attempt is made in boiling water reactors to put the fuel rods as close as possible to the coolant pipe or fuel assembly channel. Then, however, the peripheral ribs form further flow hindrances. For the sake of good fuel utilization, an attempt is also made to distribute the fuel to as many fuel rods as possible, so that the rods are therefore made thin. That means that the interstices between the fuel rods are small as well, and therefore the structural elements of the spacer, which cannot be made arbitrarily thin because of the required mechanical strength, have an increasingly disruptive influence on the coolant flow. If a change is made from clusters with eight or nine rows and columns of fuel rods to configurations with 11 rows of fuel rods in the same fuel assembly cross section, for example, then care must be taken to provide a lower flow resistance by means of a suitably flow-aiding or streamlined construction of the spacer, if the necessary coolant throughput is to be maintained. It is accordingly an object of the invention to provide a fuel assembly with a flow-aiding spacer, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which has an adequately low flow resistance. With the foregoing and other objects in view there is provided, in accordance with the invention, a fuel assembly, comprising a cluster of mutually parallel fuel rods; a fuel assembly channel laterally surrounding the cluster of fuel rods and having a substantially rectangular cross section and flat channel walls; grid-like spacers having meshes formed therein each receiving a respective one of the fuel rods for guiding the fuel rods in a plurality of axial positions; at least one support spring laterally supporting each respective one of the fuel rods in the mesh guiding the fuel rod; each of the spacers having inner ribs being aligned parallel to the fuel rods and outer peripheral ribs opposite the channel walls, at least some of the inner ribs being fastened to the peripheral ribs, and the outer peripheral ribs being joined together only by the inner ribs. With the objects of the invention in view, there is also provided a fuel assembly for a boiling water reactor, comprising an approximately central coolant pipe; a cluster of mutually parallel fuel rods surrounding the coolant pipe and defining interstices therebetween; a channel laterally surrounding the cluster of fuel rods and having walls; a grid-like spacer having meshes for guiding the fuel rods, outer peripheral ribs opposite the walls of the channel, inner peripheral ribs substantially resting on the coolant pipe, and inner ribs joining the outer ribs to the inner peripheral ribs, the outer peripheral ribs and the inner peripheral ribs having upper edges; and support springs laterally supporting the fuel rods in the meshes, the support springs being rings of tabs disposed on the respective upper edges of the outer peripheral ribs and the inner peripheral ribs and bent into the interstices, all of the tabs having upper edges disposed in an upper plane, all of the ribs having lower edges disposed in a lower plane, and the outer peripheral ribs being lower than the inner peripheral ribs between the tabs. In pressurized water reactors, the corners of the spacer must be spaced in such a way that the spacers of adjacent fuel assemblies are prevented as much as possible from catching on one another during maneuvers in the reactor. In boiling water reactors, it is difficult to assure that the corner rods will be adequately bathed with coolant. The invention therefore proposes (particularly for boiling water reactors) spacers with "open corners". In other words, the outer ribs do not directly meet one another at the corners. Instead, according to the invention, they are joined together only through inner ribs, so that a gap is created in the boundary formed by the outer ribs. In order to attain this object, the invention also takes its point of departure from the flow resistance presented by the support springs and proposes one support spring for each mesh guiding a fuel rod. The support spring has an upper and a lower bearing surface that rests on a front side facing toward the rod, of a rib surrounding the applicable mesh. These two bearing surfaces are joined to two flat legs, each adjoining a bearing surface, through a resilient middle part that is bent a single time and faces toward the fuel rod. These bearing surfaces each merge into one end of the spring and are fastened to one another in such a way that they encompass the rib. This brings about not only a first contact with the rib but also a long spring travel, which results in high elasticity and adequate contact force. In order to prevent over-stretching of the spring legs when the fuel rods are inserted and to prevent deformation of the bent middle part, the front side of the rib has a safety stop, in the form of a protrusion facing toward the resilient middle part. Published European Application No. 0 330 013 A1, corresponding to U.S. Pat. No. 5,035,853, has already disclosed a spring with upper and lower bearing surfaces, a middle part joining the bearing surfaces through flat legs, and a safety stop, but there the middle piece between the flat legs has an undulating form with one or more arched portions, facing toward the front side of the rib. The arched portions can at the same time act as a safety stop. However, a singly bent muddle part according to the invention is substantially more flow-aiding or streamlined, and therefore the flow resistance at the protrusion facing toward the resilient middle part on the front side of the rib is virtually negligible. It is normal for the outer ribs in boiling water reactors to be supported on the channel walls through knobs that are formed by two halves which are mirror images of one another and that are provided on each of the corners in rectangular fuel assemblies. In other words, each end of a rib adjacent to another rib at a corner has two such half-knobs, in the prior art. In contrast, the invention provides only one half-knob for each such rib end. In other words, the two halves of such a knob are separated from one another by a long, flat middle part of the rib. As a result, the flow resistance of the knobs is virtually halved, while the contact force is virtually unchanged. In reactors (especially boiling water reactors) with spacers which have the aforementioned tabs on their tops, the size of the tabs is limited in a practical sense by the space between adjacent fuel rods into which the tabs are bent. That prevents limitations in terms of the geometry of the inner rib, since the spacer is held on the coolant pipe there. If the height of the remaining ribs is kept low, then the flow resistance is also correspondingly low. The invention provides for the outer peripheral ribs and the inner peripheral ribs to each extend with their lower edges down to a lower plane and with the upper edges of the tabs carried by the peripheral ribs extending up to an upper plane. However, between these tabs, the height of the outer peripheral ribs is less than the height of the inner peripheral ribs. As a result, the tabs on the outer peripheral ribs are lengthened. In other words, their base is wider and the interstices between the tabs are correspondingly smaller than at the inner rib. There is accordingly still sufficient room between the tabs of the higher inner rib for the stops carried by the pipe walls to engage the tabs and come to a stop there, without requiring that the stops protrude so far into the interstice between the fuel rods that they also come to a stop at the inner ribs. In such a construction, it suffices to provide corresponding stops only in the middle of the pipe walls in each case. That lessens the flow resistance at the stops. Particularly with rectangular coolant pipes, the corners formed by abutting peripheral ribs are weak points, mechanically. In particular, the tabs mounted there rip away all the more easily as they have to be made narrower, in view of the available space between the fuel rods. In this case the invention therefore provides that at least two adjacent tabs of the inner ribs (for instance, the corner tabs of abutting peripheral inner ribs) have locations at which they can be laterally welded to one another. This creates a reinforcement of the inner ribs (for instance, a reinforced corner). Further problems arise because the inner peripheral ribs must be welded to inner ribs on one hand, but on the other hand they must offer space for accommodating spacer elements that support the inner ribs against the pipe walls. The invention provides for constructing upper and lower peripheral parts of the inner rib as contact parts, which spring back toward the fuel rods (that is, they point away from the pipe wall), and onto which a tubular or can-like inner rib forming the mesh of an adjacent fuel rod is welded or fastened on in some other suitable way. Between the upper and lower peripheral parts, a middle part of the peripheral rib is provided, on which a spacer element that supports the peripheral rib against the pipe wall is disposed. In particular, this spacer element may be a spring. The spacer elements are advantageously each disposed between the stop in the middle of a pipe wall and the corners of the coolant pipe, so that four upper and four lower stops and eight spacer elements (springs) are sufficient. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a fuel assembly with a flow-aiding spacer, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
	description	The present disclosure relates generally to a system and a method for generating plasma and more particularly to a system and a method for generating plasma and confining such plasma while compressing it. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Plasma is a state of matter similar to gas in which at least part of the particles are ionized. The presence of charged particles (e.g. positive ions and negative electrons) makes plasma electrically conductive. Plasma with a magnetic field strong enough to influence the motion of the charged particles is called magnetized plasma. A plasma torus is a magnetized plasma shaped into a toroidal configuration (donut shape), with linked poloidal and toroidal (in some cases) closed magnetic field lines. Toroidal magnetic field comprises magnetic field lines that go parallel to a magnetic axis of the plasma torus. The toroidal field is generated by a current flowing in a poloidal direction around the plasma's magnetic axis. Poloidal magnetic field comprises magnetic field lines that go around the magnetic axis of the plasma torus and is generated by a current flowing in toroidal direction, parallel to the magnetic axis. As a magnetic field line runs many turns around the plasma in the toroidal and poloidal direction, it defines a “flux surface” at a constant radius from the plasma's magnetic axis. The extent of linkage of the poloidal and toroidal magnetic fluxes defines a helicity of the plasma torus. The magnetic field in the magnetized plasma confines plasma energy by suppressing the transit of heat and particles from the core of the plasma to its edge. Since the path of charged particles in a magnetic field is confined to spirals that travel along field lines great care should be taken to ensure that the magnetic field lines run in the toroidal and poloidal direction but not along the radial direction to avoid a direct route from the core to the edge of the plasma. The plasma torus can have, for example: a spheromak configuration, a Field Reversed Configuration (FRC), a tokamak configuration, a spherical tokamak (ST) configuration, a reversed field pinch (RFP), a stellarator and any other configurations of magnetized plasma. Controlled thermonuclear fusion is based on the fusion of light nuclei present in plasma to form a heavier nucleus. Stabilization and maintaining the plasma in a stable configuration is very important for any fusion technology. In the case of magnetized plasma configurations, plasma magnetic field (poloidal and/or toroidal field component) is a key plasma property related to plasma stability and plasma performance. Maintaining a proper magnetic field structure for prolonged time is important in order to get more nuclei to fuse. Compressing plasma may increase plasma density and plasma energy so that more nuclei get to fuse in shorter time period meaning that compressed plasma need to be confined and stable for shorter time period, however compressing the plasma may cause destabilization of plasma magnetic structure and destroying plasma confinement. Thus it is important to maintain plasma magnetic structure stable during plasma compression in order to get nuclei to fuse. In one aspect, a system for generating and compressing magnetized plasma is provided. The system comprises a plasma generator with a first closed end and an outlet, and a flux conserving chamber that is in tight fluid communication with the outlet of the plasma generator, such that the generated magnetized plasma is injected into an inner cavity of the flux conserving chamber. The system further comprises an elongated central axial shaft with an upper section positioned within the plasma generator and a lower section extending out of the outlet of the plasma generator into the flux conserver. The end of the lower section of the central axial shaft is connected to the wall of the flux conserver. A gas injection system is provided to inject a gas into the plasma generator. The system further comprises a power source that comprises a formation power circuit configured to provide a formation power pulse to the plasma generator to ionize the injected gas and generate magnetized plasma, and a shaft power circuit configured to provide a shaft power pulse to the central axial shaft to generate a toroidal magnetic field into the plasma generator and the flux conserving chamber. A plasma compression driver configured to compress the plasma trapped in the inner cavity is also provided. During compression time period, the shaft power circuit is configured to provide an additional shaft current pulse to increase plasma toroidal field in order to maintain a ratio of plasma's toroidal field to plasma's poloidal field at the pre-determined range during compression. The system further comprises a controller to control the trigger time of the power source to provide the formation power pulse separately from the shaft power pulse, such that the shaft current pulse is independently controlled from the formation current pulse. In one aspect, the controller triggers the shaft power circuit prior to the formation power circuit such that a pre-existing toroidal field is provided in the flux conserving chamber before the formation of the magnetized plasma. In another aspect, the controller is programmed to provide the additional shaft current pulse at a pre-determined time. A timing of the additional shaft current pulse is determined based on a triggering time of the compression driver and a compression trajectory. In another aspect, the shaft power circuit is configured such that a profile shape of the additional shaft current pulse is designed to increase the plasma's toroidal field to match plasma's poloidal field during compression. In one aspect, a method for generating and compressing magnetized plasma is provided. The method includes injecting a gas in a plasma generator; providing a toroidal field in a flux conserver by flowing a current through a central axial shaft; providing a current pulse to the plasma generator to generate a magnetized plasma; injecting the magnetized plasma into the flux conserver; compressing the plasma using a compression driver and adjusting a shaft current pulse to maintain a ratio of plasma's toroidal field to plasma's poloidal field at a predetermined range during compression period. In addition to the aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and study of the following detailed description. FIG. 1 shows one non-limiting embodiment of a plasma generation and compression system 10 having a plasma generator 12 that is in fluid communication with an inner evacuated cavity of a flux conserving chamber 14 (also sometimes referred to as a flux conserver 14). The plasma system 10 is at least partially evacuated using a pumping system (not shown). The generator 12 is configured to generate a magnetized plasma 20 and can have a first (closed) end 11 and an outlet 13 that is in fluid communication with the inner cavity of the flux conserving chamber 14. The plasma generator 12 can comprise an inner, formation electrode 15 coaxial with a longitudinal axis 19 of the system 10 and an outer electrode 16 that is coaxial to and surrounds the inner formation electrode 15 thus forming an annular plasma propagating channel 17 therein between. The plasma generator 12 can further comprise an elongated central axial shaft 30 that extends out of the generator 12 into the flux conserver 14. An upper section 31 of the central shaft 30 is positioned within the plasma generator 12 while a lower section 33 of the shaft 30 extends along the axis 19 into the flux conserving chamber 14, such that a second end 30b of the central shaft 30 can be in contact to an end plate 34 of the flux conserving chamber 14. A first end 30a of the shaft 30 can be separated from the formation electrode 15 forming a gap 32 therein between. In the illustrated example, the outer electrode 16, the inner electrode 15 and the upper section 31 of the shaft 30 have a slightly tapering configuration toward the outlet 13, such that the plasma propagation channel 17 has a tapered configuration as well, meaning that a circumference of the plasma propagation channel 17 at the first end 11 is greater than the circumference of the channel 17 at the outlet 13. However, person skilled in the art would understand that the outer and inner electrodes 16, 15 and the shaft 30 can all have cylindrical shape forming a propagation channel 17 with straight configuration without departing from the scope of the invention. In one implementation, the outer electrode 16 can have tapered geometry while inner electrode 15 and the shaft 30 can have cylindrical geometry and provide a plasma propagation channel 17 with a tapered geometry. In the illustrated example shown in FIG. 1, the shaft 30 is shaped such that its upper section 31 is generally conically shaped while its lower section 33 is generally cylindrical. This is for illustration purposes only and the size and the shape of the central shaft is determined based on the size and shape of the flux conserver 14 and the parameters of the plasma generator 12. For example, the shaft 30 can have generally cylindrical shape through the entire length or it can have any other suitable shape or a combination thereof without departing from the scope of the invention. The size and the shape of the shaft 30 define the size and the shape of a portion of the plasma channel 17 defined as an annular space between the central shaft 30 and the outer electrode 16. The flux conserver 14, the axial shaft 30 and the electrodes 15 and 16 are made from a conductive and high-vacuum-compatible material. In one implementation, the upper section 31 of the shaft 30 can be a liquid metal reservoir that contains a liquid metal, and the lower section 33 of the shaft 30 can be a liquid metal guide that flows out through the outlet formed in the liquid metal reservoir, through the flux conserver 14 and into a catcher (not shown) positioned, for example, within the end plate 34. The liquid metal from the catcher can be recirculated back into the liquid metal reservoir using one or more pumps. The liquid guide can flow continuously or the flow can be regulated using a valve that is in communication with the reservoir's outlet. The flux conserver 14 can comprise an opening that is aligned with the outlet 13 of the plasma generator 12 so that the plasma 20 generated in the plasma generator 12 can be injected into the inner evacuated cavity. The flux conserver 14 can further comprise a liner 36 that defines the inner evacuated cavity. For example, the liner 36 can be formed by injecting a liquid medium into the flux conserver 14 forming the evacuated cavity. Examples of liquid liners and methods for forming evacuated cavity into the liquid liners are described in U.S. Pat. Nos. 8,891,719, 8,537,958 and US patent application publication No. 20100163130. In one implementation, the liner 36 can be a solid liner, such as for example a wall of the flux conserver 14 or a solid liner attached to/coated on an inner side of the wall of the flux conserver 14. A series of magnetic coils 18 can be used to form an initial (stuffing) magnetic field in the plasma propagation channel 17. For example, some of the coils 18 can be positioned within the inner electrode 15 while some of the coils 18 can be positioned around the outer electrode 16, such that a desired configuration of the initial stuffing magnetic field is distributed in the plasma propagation channel 17 before the formation of the plasma. The magnetic field lines of the stuffing magnetic field extend between the inner and the outer electrodes 15 and 16. Any number of coils 18 can be provided and positioned around or within the plasma generator 12 to provide the desired strength and configuration of the initial magnetic field. In some implementation, a high permeability (e.g. ferromagnetic) core can be included within the inner electrode 15 and/or within the axial shaft 30 in order to concentrate initial (stuffing) magnetic field. A number of gas valves 22 that are in fluid communication with the annular plasma propagation channel 17 are arranged as a ring around the periphery of the plasma generator 12 to symmetrically inject a precise quantity of gas into the channel 17. Each of the valves 22 are in fluid communication with a gas reservoir (not shown) and are operable to provide a substantially symmetrical introduction of the gas into the channel 17 of the plasma generator 12. The injected gas can be for example, one or more isotopes of light elements i.e., isotopes of hydrogen (e.g., deuterium and/or tritium) and/or isotopes of helium (e.g., helium-3) or any other gas or gas mixture. The system 10 further comprises a power source comprising a formation power circuit 24 which includes at least one capacitor bank. The power source comprising the formation power circuit 24 can be a pulsed power source configured to provide a discharge pulse to the inner electrode 15 so that a current flows from the inner electrode 15, across the gas to the outer electrode 16, ionizing the gas and forming plasma. The coils 18 setup the initial stuffing magnetic field prior to the gas being injected into the annular plasma propagation channel 17 and prior to the current being discharged between the electrodes 15 and 16. For example, the stuffing magnetic field can be applied a few seconds before the discharge. Once the gas diffuses to at least partially fill the channel 17, the power source 24 can be triggered causing a formation current pulse to flow between the electrodes 15 and 16. The current passes through the gas in a substantially radial direction, ionizing the gas and forming the plasma. This current can create a plasma toroidal magnetic field, and the gradient of the magnetic pressure can exert a force (Lorentz force) {right arrow over (I)}×{right arrow over (B)} that can cause motion of the plasma down the annular channel 17 toward the flux conserver 14. As the plasma moves forward, it interacts with the stuffing magnetic field generated by the coils 18. The force that displaces the plasma toward the flux conserver 14 has sufficient strength to overcome the tension force of the stuffing magnetic field so that the stuffing field is weakened and deformed by the advancing plasma (bubbling stage). Eventually the plasma breaks free so that the magnetic field can wrap around the plasma forming a magnetized plasma torus 20 with a poloidal magnetic field and a toroidal magnetic field. The magnetized plasma 20 can be a toroidal plasma such as for example, a spheromak, a spherical tokamak or any other suitable configuration of magnetized plasma. The central shaft 30 is electrically isolated from the inner electrode 15 and is electrically conductive, so that a current flowing through the central shaft 30 generates a toroidal magnetic field in the plasma generator 12 and the flux conserver 14. For example, an additional power source comprising a shaft power circuit 26 can provide a power pulse to the central axial shaft 30. The additional power source comprising the shaft power circuit 26 can be a pulsed power source. In one implementation, a single pulsed power source can provide both a formation power pulse to the formation electrode 15 and a shaft shaft's power pulse to the central shaft 30 without departing from the scope of the invention. For example, the power source can comprise the formation power circuit 24 and the shaft power circuit 26. The current provided by the shaft power circuit 26 flows along the shaft 30 and back on an inner wall of the flux conserving chamber 14 and the outer electrode 16, thus generating a toroidal field within the plasma generator 12 and flux conserver 14. The toroidal field formed by the shaft current flow has magnetic lines that extend around the central axial shaft 30. The shaft power circuit 26 can provide the power pulse to the central axial shaft 30 ahead of the plasma formation pulse thereby creating a toroidal magnetic field in the plasma generator 12 and the flux conserver 14 before the formation of the plasma 20. So, the plasma formation can occur with a pre-existing toroidal field in the plasma generator 12 and the flux conserver 14. When the formation pulse is discharged and the plasma is accelerated down the plasma generator 12 due to the Lorentz force, it will push such preexisting toroidal field deflecting its field lines. This toroidal field can diffuse into the plasma and can increase plasma toroidal field. FIG. 2 upper plot shows an example of a formation current curve 210 and a shaft current curve 220 while lower plot shows a formation voltage curve 212 and a shaft voltage curve 222. As can be noticed from the illustrated example, the formation current pulse can be about ˜700 kA for a duration of about 90 μs, while the shaft current is about 400 kA and is triggered about 110 μs prior to the triggering time of the formation current pulse. This is for illustration purposes only, and the triggering time of the shaft pulse can be determined depending on the properties of the power source comprising the shaft power circuit 26, desired parameters of the plasma 20 and the size and geometry of the plasma system 10. In addition, the shaft current pulse can be set such that the current can continue flowing long after the plasma 20 is formed and injected into the flux conserving chamber 14, so that the current flowing can put additional toroidal field into the plasma. For example, the shaft's current pulse can last about 2 ms while the formation current pulse last about 80 μs. The longer shaft current pulse can help in controlling plasma stability and confinement by controlling plasma safety factor q. The safety factor q can best be described by tracing out a magnetic field line in the plasma and counting the number of toroidal turns it completes before completing one poloidal turn. q-factor at the plasma's core is in general different than q-factor at the plasma's edge, so q-profile is plasma's q-factor along its radius. When q is a rational number (i.e. 1/2, 1, 3/2, 2 etc.) the plasma will resonate and will develop an asymmetry. Often this asymmetry rotates around the torus and can be detected by the phase of signals obtained from a number of sensors as an oscillation in time. Such an asymmetry can reduce the heat confinement of the plasma configuration. So, fine tuning and adjustment of the plasma's q-profile can result in low plasma fluctuations and improved plasma confinement. Measuring plasma's q-profile and its control in real time is complex exercise requiring complex modeling. However, the inventors have found that the ratio of plasma's toroidal field to the poloidal field can be used as a proxy for q-profile measurements. The ratio of the toroidal to poloidal field can be controlled and maintained to an empirically determined optimum value/range that relates to a predetermined q-value. Control of the toroidal field can be achieved by adjusting the shaft current pulse. For example, if the magnetic field ratio falls below the empirically determined optimum value, the toroidal field can be increased by increasing the shaft current pulse, which will raise the magnetic field ratio up, keeping the plasma's q between critical values. For example, the pre-determined q-value can be any value different than a rational number, such as for example, greater than 1 and smaller than 3/2 (1<q<3/2). The system 10 can comprise a number of viewing ports at various axial positions along the plasma generator 12 and/or flux conserver 14 to accommodate various measuring probes/detectors. An array of diagnostics can be provided to measure plasma's parameters (e.g. magnetic field, temperature, density, impurities), as well as system's parameters (e.g. current, voltage, etc.). Plasma magnetic configuration can be determined using an array of magnetic probes, such as for example B-dot probes or any other suitable magnetic probes. Such magnetic probes can be positioned in the wall of the central axial shaft 30, the flux conserver 14, and/or the plasma generator 12 and can be configured to provide signals of both the poloidal and toroidal field in the plasma at various axial/radial and/or angular positions over time. Each of the magnetic probes can provide one signal for plasma's poloidal field and another signal for plasma's toroidal field. For example, each of the probes can comprise two separate coils located near probe's tip. One of the coils can be oriented so that it will capture the signal of plasma's poloidal field and the other coil can be directed to measure plasma's toroidal field. Each of the probes can be at different radial, axial and/or angular position so that the magnetic field at various radial, axial and/or angular positions can be measured over time. For example, FIG. 3 upper plot illustrates an example of a plasma poloidal field over time obtained from different probes (one curve per probe) positioned on the central shaft 30 (providing signals of plasma magnetic field at the inner edge of the plasma) while the lower plot illustrates the plasma poloidal field over time obtained from the probes positioned near the wall of the flux conserver (signals od plasma magnetic field at the outer edge of the plasma torus). The signals at the upper plot are from probes positioned at the same radial position (R=9 mm distance from the longitudinal axis 19 of the flux conserver 14) but different axial/angular position, while the signals at the lower plot are from probes positioned at the wall of the flux conserver 14 at various radial, axial and angular positions. As can be noticed, the plasma poloidal field in proximity to the central axial shaft has peak poloidal field of about 0.9 T while in proximity to the outer wall the peak poloidal field is about 0.25 T. The poloidal field decays after 1.7 ms, indicating a plasma life of about 1.7 ms. The signals from the magnetic probes can be used to estimate total toroidal field ΔBtor and total poloidal field ΔBpol and determine average q-profile. Being able to measure and determine plasma magnetic configuration is important to measure and control plasma q-profile since based on the signals obtained from the magnetic probes one can adjust the shaft current pulse in order to keep plasma q-profile within a pre-determined range. The system 10 can further comprise a compression driver 21 configured to compress the plasma 20. For example, the compression driver can comprise a plurality of pneumatic pistons that generate a pressure wave in the liquid liner as described in US patent application publication No. 20100163130. So the generated pressure wave converges inward collapsing the inner cavity and compressing the plasma trapped therein. In one implementation, the compression driver can be a plurality of pneumatic valves or plasma guns or a chemical driver that can compress plasma by pushing the liner 36. Any other suitable compression driver configured to compress plasma can be used without departing from the scope of the invention. The system 10 can further comprise a controller 23 that is in communication with the formation power circuit 24, shaft power circuit 26, compression driver 21 and diagnostic probes, i.e. magnetic probes. The controller 23 can be used to control the timing and duration of the formation current pulse, the shaft current pulse and the compression driver 21. The controller 23 can comprise an input unit, an output unit and a processing unit. The controller 23 can be configured to independently control the shaft power circuit 26 and the formation power circuit 24. The shaft power circuit 26 can be designed as a single stage or multi-stage circuit to provide and sustain sufficient toroidal field in the flux conserver 14 for a desired plasma configuration. For example, the shaft power circuit 26 can be designed as a 2-stage circuit, such that in the first stage it provides a current pulse that rapidly reaches peak current and provides the pre-existing toroidal field before plasma formation, and a second stage to maintain the current flow against resistive loses (e.g. the resistive loses in the conductors). In some implementations, the shaft power circuit 26 can provide an additional shaft current pulse to increase plasma's toroidal field at pre-determined time and for pre-determined duration. For example, if the signals provided by the magnetic probes indicate increase of the poloidal field, the controller 23 can trigger the shaft current circuit to increase the shaft current. By increasing the shaft current, the toroidal field of the plasma 20 is increased, thus maintaining the ratio of the toroidal and poloidal field and keeping the plasma q-factor at the pre-determined value. Increasing of plasma poloidal field can happen for example, during plasma compression. When the compression driver 21 is triggered, it compresses the plasma 20 increasing its poloidal field thus bringing the plasma q-factor below its pre-determined value (e.g. plasma q-factor can hit rational number q=1) which may destabilize plasma magnetic field destroying plasma confinement. In order to maintain plasma stability during compression the safety factor q is maintained at a predetermined value/range by increasing the shaft current during compression. FIG. 4 shows a formation current pulse 310 and a shaft current pulse 320 with time during plasma compression. As can be noticed, shaft current is increased/ramped up (see jump 325) during the compression time period 330. The shaft current circuit can be configured to increase the shaft current pulse for at pre-determined time period until the liner 36 that moves inward compressing plasma 20 closes the outlet 13 (gap formed by the plasma propagation channel 17 at the outlet 13). Once the outlet 13 is closed, a closed current loop is formed around the plasma 20, trapping the toroidal field in the flux conserver 14, so that the toroidal field will continue increasing at the same rate as the poloidal field without any further increase of the shaft current from the shaft power supply. FIG. 5 shows examples of a numerical model of the plasma generation and compression system 10. Examples in the left column are numerical models of the system 10 and plasma's confinement and stability behavior during compression when the central shaft current pulse is maintained constant during compression period Ishaft(t)=Io, and in the right column are models of plasma's confinement and stability behavior during compression when shaft's current increases during compression as Ishaft(t)∝1/r(t), where r(t) is radius of the plasma. As can be noticed, when shaft current is constant during compression period the magnetic field confining the plasma gets disturbed destroying the plasma confinement, while by increasing the shaft current generally proportionally with the compression ratio the plasma magnetic field is maintained stable keeping the plasma stable during compression. FIG. 6 shows the magnetic field during one compression experiment when the shaft current was ramped up to maintain plasma's toroidal to poloidal magnetic field ratio at pre-determined range to keep plasma stable during compression. Upper plot shows plasma poloidal field while the lower plot shows plasma toroidal field for the same shot. As can be noticed the signals obtained from the magnetic probes during compression are smooth and overlapping (no oscillation) indicating a stable plasma magnetic field during compression. FIG. 7 depicts plasma magnetic field during a compression experiment when the shaft current is not ramped up showing deviating (oscillations) magnetic field signals 600 which indicates that the plasma magnetic structure is destabilized. Thus, ramping up the shaft current during compression period keeps the plasma stable during compression. The increase of the shaft current pulse during compression can be done actively in real time by monitoring the signals from the magnetic probes. The controller 23 can process the signals obtain from the magnetic probes in real time and when an increase in the plasma poloidal field is detected the controller can trigger the shaft power circuit to increase the shaft current pulse to match the increase of the poloidal field. In another implementation, the controller 23 can be programmed to trigger the shaft current circuit to increase the shaft current at pre-determined time based on a triggering time of the compression driver 21 and compression trajectory (e.g. trajectory of the liner 36 over time during compression). In one embodiment, the increase of the shaft current pulse can be triggered before the compression period, so that the toroidal field generated by the shaft current can diffuse into the plasma and thus match the raise in the poloidal field. For example, the additional (ramp) current pulse can be triggered 10-150 μs before the liner's wall moves inward (start of the compression). In one embodiment, the additional shaft current pulse can match the trigger time of the compression driver 21. FIG. 6 lower plot shows that the additional shaft current pulse was triggered about 10 μs ahead of the liner wall moves (start of the compression). More than one additional shaft current pulses can be provided during compression period to match the profile of the poloidal field curve and keep the plasma stable. FIG. 6 lower plot indicates that five additional shaft current pulses were triggered to keep the toroidal field increasing as the poloidal field increases due to plasma compression. However, person skilled in the art would understand that the shaft power source can be configured so that it can provide a single additional shaft pulse with a desired profile. The compression trajectory (e.g. trajectory of the liner 36) can be determined experimentally or analytically and a timing table for the shaft current circuit can be fed into controller 23 so that the additional shaft current pulse can be pre-set based on the trigger time of the compression driver 21 and the compression trajectory. The plasma obtained in any of the disclosed embodiments can be a high energy plasma and can be suitable for applications such as, e.g., production of medical isotopes, neutron source, x-ray radiation source, nuclear fusion devices, etc. Certain embodiments of the system may be configured and operated to act as neutron generators or neutron sources. Neutrons so produced have a wide range of practical uses in research and industrial fields. For example, a neutron source can be used for neutron activation analysis (NAA) which can provide multi-element analysis of major, minor, trace, and rare elements in a variety of substances (e.g., explosives, drugs, fissile materials, poisons, etc.) and can be used in a variety of applications (e.g., explosive detection and identification, ecological monitoring of the environment or nuclear waste, etc.). Embodiments of the system configured as a neutron source can also be used for materials research (e.g., analyzing the structure, dynamics, composition, and chemical uniformity of materials), for non-destructive testing of industrial objects (e.g., via neutron radiography and/or neutron tomography), and for many other industrial and technological applications. While particular elements, embodiments and applications of the present disclosure have been shown and described, it will be understood, that the scope of the disclosure is not limited thereto, since modifications can be made without departing from the scope of the present disclosure, particularly in light of the foregoing teachings. Thus, for example, in any method or process disclosed herein, the acts or operations making up the method/process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Elements and components can be configured or arranged differently, combined, and/or eliminated in various embodiments. The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of this disclosure. Reference throughout this disclosure to “some embodiments,” “an embodiment,” or the like, means that a particular feature, structure, step, process, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in some embodiments,” “in an embodiment,” or the like, throughout this disclosure are not necessarily all referring to the same embodiment and may refer to one or more of the same or different embodiments. Various aspects and advantages of the embodiments have been described where appropriate. It is to be understood that not necessarily all such aspects or advantages may be achieved in accordance with any particular embodiment. Thus, for example, it should be recognized that the various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may be taught or suggested herein. Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without operator input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. No single feature or group of features is required for or indispensable to any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z to each be present. The example calculations, simulations, results, graphs, values, and parameters of the embodiments described herein are intended to illustrate and not to limit the disclosed embodiments. Other embodiments can be configured and/or operated differently than the illustrative examples described herein.
039473210	description	Referring to the drawings, the reactor comprises a mass 1 of graphite moderator in which is disposed suitable fissionable material (not shown), all of which is enclosed in a suitable biological shield 2, or a shield of a material of sufficient radiation absorption characteristics and thickness to protect living organisms outside of it from radiation. Passages 3 extend through one shield 2 and into the mass 1 for accommodating control rods 4 and are lined with aluminum tubes of the same general cross section as the rods 4 and only slightly larger, the tubes being sealed in place to prevent escape of helium from the reactor. The rods in the example shown are arranged in vertically spaced tiers, three rods in each tier, the tiers and the rods of each tier being spaced about five feet apart. Each rod proper contains neutron absorbing material and is water cooled. A driven means, which preferably is in the form of a rack 5, is connected fixedly to each rod in end to end relationship and is rigid with the rod and forms a linear extension thereof, the rod proper and driven means in the illustrative example forming in effect opposite end portions, respectively, of a unitary rod structure. The driven means or rack 5 cooperates with a driving means, which includes a reversible motor driven pinion 6, for driving the rods selectively endwise in opposite directions. The rods are supported on rollers 7 which are carried on a suitable framework 8. The rods are water cooled by circulating water therethrough from suitable inlet and outlet hoses 9 carried on reels 10. The driving means for the rods, including the pinions and motors (the motors not shown) and the water circulating fittings are shielded from the reactor by means of a shield wall 11. The wall 11 has rod passages 12 therein and is the end wall of a room 13, the opposite wall of which is the shield 2 of the lateral face of the reactor. The room 13 is kept completely closed, except for the passages 12 in the wall 11 and the passages 3 into the reactor, access being had to the room only by a suitable shield door (not shown) which normally is kept closed and locked. The room 13 is known as the "hot room" and is of greater length, endwise of the rods, than the length of those portions of the rods which are capable of insertion into the reactor. For example, the rods illustrated can be inserted into the reactor to a depth of about 28 feet and the length of the room 13 is about 31 feet. Consequently, upon fully withdrawing a rod which is active due to neutronic bombardment in the reactor passages 3, the active portion lies wholly within the room 13 and no active part of the rod is exposed outwardly of the wall 11. The desirability of such shielding is apparent from the fact that the rods emit about 10,000 roentgens per hour upon withdrawal from a pile of 250,000 kilowatts capacity and may not be approached safely for about a week after withdrawal. In cross section, the passages 3 and 12 fit the cross sections of the rods 4 with very slight clearance so that, while a rod extends into the passages, the stream of neutrons issuing around the rod through the passages is substantially blocked or greatly reduced compared to the stream of neutrons which would issue from a fully open end of a passage 3 or 12. However, when a rod is fully removed from a passage 3 a stream of very high neutron and other radiations, such as gamma radiations, emanates from the passage. To prevent such direct radiations, suitable shield gates are provided. The main shielding of the passages 3 is effected by main shield gates 14, arranged one for each passage 3. As better illustrated in FIGS. 2 through 6, each gate 14 comprises a frame 15 which is rigidly mounted directly in front of the open end of one of the passages 3. Mounted in each frame 15 is a plug 16 which is movable laterally of the axis of the associated passage 3 in a suitable guideway in the frame 15. The plug 16 has a lead portion positioned to overlie the open end of the passage 3 when the plug 16 is in closed position. The plug 16 is operated by a suitable double acting pneumatic piston 18 which is fixedly secured to the frame 15 and which moves plug 16 back and forth by means of piston rod 17, as shown in FIGS. 3, 4, and 6. Each piston 18 is individually controlled by suitable remote control valves (not shown) to move the plug 16 in front of and clear from the passages 3 selectively. Limit switches 18a are provided which are engaged by adjustable stop members 18b riding on the plug 16, the stop member 18b to the right breaking an electric circuit when the piston rod 17 is retracted causing the member to strike the limiting switch 18a to the right, thereby actuating a relay (not shown) so as to cause the retracting motion to stop, and conversely the stop member 18b to the left breaking an electrical circuit when the piston rod pushes plug 16 forward to the closed position, thereby actuating a relay (not shown) so as to cause the forward motion of piston rod 17 to stop. In cases wherein it becomes necessary to remove a rod for service or repair, it is necessary also to prevent radiation from the "hot room" 13 out through the passages 12 where it would be dangerous to personnel directly exposed and would contaminate the operating equipment. For this purpose, each passage 12 is provided at its inner end with an intermediate gate 19, as better illustrated in FIGS. 7 and 8. The passages 12 are provided with suitable sleeve liners 20 and headers 21 and the gates 19 are fixed in position in front of the passages on the inner face of the wall 11. Each gate 19 comprises a frame 22 in which a plug 23 is movable in opposite directions by a jack-screw 24. The screw 24 is operated by an internally threaded bevel gear 25 rotatably mounted in the frame 22. Each gear 25 cooperates with a driving gear 26 which is rotatable by a rotatable shaft 27, operated in turn by a detachable crank 28 from locations outside of and shielded from the room 13. Each plug 23 is thus operable to be moved into alignment with its associated passage 12 and clear thereof, and each has a lead portion 29 for preventing the passage of radiations through its associated passage 12 when the lead portion is brought into alignment therewith. Thus, personnel and the operating equipment are protected both from direct radiation from the rods 14 and passages 3 and from radiations from the room 13. The wall 11 preferably is of hydrogeneous concrete and may be 5 feet or more in thickness. The other walls of the room 13 are of comparable thickness. The lead portions of the gates may be 6 inches thick in a direction lengthwise of the passages. The aforesaid dimensions will, of course, depend upon the power of the particular reactor. As mentioned, the rods 4 are fluid cooled, and the water is circulated therethrough from hoses 9 in the apparatus or control room. To reduce radiation from the water to a minimum while affording adequate cooling of the rods 4, each rod, as illustrated in FIG. 9, preferably is formed from aluminum blocks 29 in which are enclosed a water inlet tube 30 and outlet tubes 31 which connect to inlet and outlet hoses 9, respectively. The tubes 30 and 31 are spray coated exteriorly with a layer of boron which absorbs neutrons effectively and reduces the possibility of rendering active any foreign matter which may be present in the cooling water. Water is circulated through the tubes at a rate of about 10 gallons per minute. The activity of the rods decays very rapidly so that after about a week the rods can be approached to within a foot or so safely without exceeding a tolerance dose in 8 hours. Having thus described the invention, what is claimed is:
	description	An embodiment of the present invention will be described below with reference to the accompanying drawing. A used radiation protector cast into a hopper 1 is sent to a radiation protector pulverizer 2 where it is pulverized to obtain a pulverized radiation protector material. During the pulverization, an appropriate amount of powder is cast into the radiation protector pulverizer 2 from each of a boron powder storage tank A and a bismuth powder storage tank B, which are connected to the radiation protector pulverizer 2. Thus, the pulverized radiation protector material is mixed with the added powders. The boron powder mixed with the pulverized radiation protector material attenuates the energy of neutrons emitted from radioactive substances attached to the pulverized radiation protector material, and the bismuth powder attenuates the energy of gamma radiation emitted by radioactive substances attached to the pulverized radiation protector material to reduce the influence of gamma radiation. Next, the pulverized radiation protector material mixed with the radiation attenuating and absorbing powders is sent into an electric melting furnace 4 by a conveyor 3. While the pulverized radiation protector material is being cast into the electric melting furnace 4, an appropriate amount of powder is cast into the electric melting furnace 4 from each of a silicon powder storage tank C, a lead oxide powder storage tank D and a carbon powder storage tank E, which are connected to the electric melting furnace 4. The added silicon powder is a material for forming the pulverized radiation protector material melted in the electric melting furnace 4 into a glassy state. The lead oxide powder changes the glassy material into a soft state (lead glass) to confine the emissions from radioactive substances. The amount of silicon powder added is larger than the amount of lead oxide powder added. The carbon powder mixed with the pulverized radiation protector material is a material for adjusting the electric current flowing between electrodes used in the electric melting furnace 4. The carbon powder allows the melt temperature of the pulverized radiation protector material to be adjusted with any desired electric current. The molten pulverized radiation protector material forms a glassy melt with the silicon powder and the lead oxide powder. The molten glass of the pulverized radiation protector material flows out of the electric melting furnace 4 into a cooling vessel 5. The molten glass of the pulverized radiation protector material flowing into the cooling vessel 5 cools down with time to become a solid glass body. The energy of radiation from the solidified glass of the pulverized radiation protector material, particularly the energy of gamma radiation and neutrons, is reduced. Regarding exhaust gas from the electric melting furnace 4, radioactive exhaust gas and other noxious gas are absorbed by a carbon gas absorber in a filter 6, and the exhaust gas is stored in a subsequent terminal chamber 7. The terminal chamber 7 is a closed chamber. Even if a radioactive gas flows into the terminal chamber 7, radiation cannot leak out of it.
	claims	1. An amplifying optical cavity of the FABRY-PEROT type for producing monochromatic X-rays through a COMPTON reaction of a high-rate picoseconds pulsed laser beam with a synchronized electron beam, the cavity comprising a closed enclosure operably being vacuumed, traversed by an electron beam tube, the enclosure comprising a laser, at least a first actuator operably maintaining and positioning two plane optical reflectors, and at least a second actuator operably maintaining and positioning two spherical optical reflectors operably focusing the laser beam at a point of interaction with the electron beam, wherein the optical reflectors are arranged by the first and second actuators such that the optical reflectors substantially define the vertexes of a tetrahedron. 2. An amplifying optical cavity according to claim 1, wherein the spherical optical reflectors second actuator has two complementary clearances, arranged so as to define a bay for the passage of the electron beam tube. 3. An amplifying optical cavity according to claim 1, wherein at least one of the actuators comprise an orienting member for orienting the associated reflector made from a single mechanical piece, including at least three distinct portions, movable with respect to each other, by flexible hinges. 4. An amplifying optical cavity according to claim 3, wherein the three distinct portions of the orienting member are movable around two rotation axes converging at one point substantially confounded with the optical center of the reflector. 5. An amplifying optical cavity according to claim 1, wherein at least one of the actuators is actuated by linear electric motors encapsulated within a sealed enclosure made of stainless steel and extended by a bellows. 6. An amplifying optical cavity according to claim 5, wherein the linear electric motors are kept in permanent contact with respect to the at least one actuator by a spring element which generates a return force. 7. An amplifying optical cavity according to claim 1, wherein at least one of the actuators has a Z-axis translation table, the translation table supporting two linear electric motors capable of actuating the reflector orienting member. 8. An amplifying optical cavity according to claim 1, wherein at least one of the actuators has a piezoelectric actuator oriented along the direction of the reflector optical axis and maintained in position by a spring ring. 9. An amplifying optical cavity according to claim 1, wherein all of the actuators are positioned on a main support, the main support being the only piece contacting the closed enclosure. 10. A system for producing monochromatic X-rays through a COMPTON reaction, comprising an amplifying, FABRY-PEROT optical cavity comprising a high-rate picoseconds pulsed laser beam with a synchronized electron beam, the cavity comprising a closed enclosure operably being vacuumed, traversed by an electron beam tube, the enclosure comprising a laser, at least a first actuator operably maintaining and positioning two plane optical reflectors, and at least a second actuator operably maintaining and positioning two spherical optical reflectors operably focusing the laser beam at a point of interaction with the electron beam, wherein the optical reflectors are arranged by the first and second actuators such that the optical reflectors substantially define the vertexes of a tetrahedron.
053848179	summary	FIELD OF THE INVENTION This invention relates to x-ray reflective structures and to methods for their manufacture. BACKGROUND OF THE INVENTION Optical elements capable of reflecting a beam of x-rays in preselected directions are useful in a variety of apparatus including x-ray monochromators, x-ray analyzers, x-ray imaging systems such as x-ray microscopes and the like. X-ray fluorescence is widely used for the qualitative and quantitative analysis of a variety of materials and the technique relies upon the use of an x-ray reflective element to resolve a multiple wavelength flux of x-rays into its component wavelengths through Bragg reflection. Bragg reflection is a phenomenon well known in the art and occurs when a beam of energy, such as x-rays is reflected from a series of planes of a periodic structure, such as a crystal. The reflections from the multiple planes establish an interference condition and the reflected wavelength will depend upon both the angle of incidence, .theta. and the spacing of the periodic structure referred to as "d". The reflected wavelength will be defined by the Bragg equation: EQU n.lambda.=2d sin .theta. wherein n is the order of the diffraction. It will thus be appreciated that such x-ray reflective structures can be the functional equivalents of elements such as diffraction gratings, prisms, mirrors or lenses which are used at visible wavelengths. Natural crystals have previously been employed as x-ray reflective elements; however, the utility of these materials has been limited by the fact that the d-spacing of the crystalline planes is defined by the lattice parameters of the crystal. Also, a number of crystalline materials are unsuitable because they do not adequately reflect the appropriate wavelengths of x-rays and/or because they fluoresce or otherwise interfere with the intended use of the reflective element. Natural crystals generally have lattice spacings which do not significantly exceed 10 angstroms. These spacings are adequate for fairly high energy x-rays; however, in many instances it is desirable to measure the x-ray fluorescence of relatively light elements; therefore, relatively soft, long wavelength x-rays must be employed thereby necessitating d-spacings significantly larger than those found in natural crystals. Toward that end, the art has investigated a number of synthetic structures. The earliest structures were comprised of molecular layers of heavy metal soaps, such as lead myristate or lead stearate. These materials are referred to as Langmurr-Blodgett (LB) films. While they can provide large lattice spacings, their lattice parameters are limited to specific values. Furthermore, the materials are soft, and difficult to prepare and are very unstable in ambient conditions; they also tend to decompose under high fluxes of x-rays. Another approach involves the use of multilayered thin films. These reflective structures comprise a plurality of stacked layer pairs. One member of each pair comprises a material having a very high x-ray reflectivity, and the second member of the pair, often referred to as a spacer, comprises a material having a lower reflectivity. In this manner, there is provided a periodic structure which is the one dimensional analog of a crystal. It will be appreciated that the thicknesses of the layers may be controlled so as to provide for a great deal of selectivity in the spacing. Such structures, and techniques for their manufacture, are disclosed in U.S. Pat. Nos. 4,693,933; 4,727,000 and 4,785,470, the disclosures of which are incorporated herein by reference. Synthetic multi-layer structures are widely used in x-ray fluorescence analyzers; however, the performance of presently available multi-layer x-ray optical elements is less than adequate with regard to the analysis of relatively light elements such as nitrogen, oxygen and fluorine. This is because of the fact that the K shell fluorescent emission from these elements constitutes relatively soft x-radiation, and an element optimized for the Bragg reflection of these wavelengths requires a spacer material which has a relatively low absorption for soft x-rays. Also, operation at soft wavelengths, particularly those associated with the "water window" is important for x-ray microscopy; and consequently there is a need for imaging optics operative in this range. Multilayer technology allows for the coating of spherical, cylindrical, or other curved and irregular shapes so as to provide unique optical elements. Also, synthetic, multilayered structures may be fabricated with a graded d spacing wherein d varies across the surface of the structure. Such graded d spacing directs the reflected beam and controls reflection and are particularly useful as focusing elements. Operation at soft x-ray energies is difficult because many of the conventionally employed spacer materials such as carbon, silicon, magnesium and the like are too absorbing to be part of an efficient reflective element operative at relatively low energies. In accord with one prior art approach, a multilayer structure of iron and scandium may be employed as a reflective element for relatively soft x-rays. In this structure, iron acts as the reflective layer and scandium as the spacer. Scandium itself is a fairly high electron density material which is generally quite reflective of x-rays; however, scandium has the unusual property of having a resonance in its optical constants which produces a low absorption window at approximately 0.39 KeV. While the iron scandium structure is quite efficient at this specific energy range it is a very poor reflective element at energies only slightly higher and slightly lower. Hence its utility is limited primarily to nitrogen detection in the energy range of 0.39 KeV. In addition to being of relatively limited utility, this structure is somewhat difficult to fabricate. It is difficult to obtain smooth interfaces between the iron and scandium layers, and the poor interface quality degrades device performance. The device also presents problems of stability because of the high reactivity of scandium, especially when in the form of thin layers. Another prior art approach to this problem is disclosed by Boher et al. in a paper entitled "Tungsten/Boron Nitride Multilayers for X-UV Optical Applications" published in SPIE, vol. 1546, Multilayer and Grazing Incidence X-ray/EUV Optics (1991) pp 520-536. Disclosed in this reference is the fabrication of tungsten/boron nitride x-ray reflective elements by reactive radio frequency diode sputtering. As noted therein, the boron nitride tends to decompose during the R.F. diode sputtering process; and consequently, a specifically controlled amount of nitrogen must be added to the deposition environment to control the stoichiometry of the resultant layer. Because of the difficulty in the control of the process and the lower than desired reflectivity of the resultant structure, there is still a need for an easy to fabricate an efficient, x-ray reflective element which can be used in the x-ray fluorescence analysis of relatively light elements; and most particularly in the wavelength region of 23-43 .ANG. (normal incidence), as is typically encountered in the case of x-ray imaging optics such as in an x-ray microscope. As will be described in further detail herein below, the present invention provides for improved x-ray optical elements having boron nitride based spacer layers, fabricated by a process which is easy to implement and control. The optical elements are highly efficient, environmentally stable and usable over a relatively wide energy range. These and other advantages of the present invention will be readily apparent from the drawings, discussion and description which follow: BRIEF DESCRIPTION OF THE INVENTION There is disclosed herein an x-ray reflective structure comprising a plurality of superposed layer pairs. The first member of each pair comprises a layer of boron nitride and a second member of each pair comprises a layer of a material selected from the group consisting of: nickel, cobalt, chromium, vanadium, iron, manganese, and combinations thereof. The x-ray dispersive structure has a d-spacing which is in the range of 10-200 angstroms. In one embodiment the structure comprises at least 50 pairs of layers. In one specific embodiment the d-spacing is approximately 55 angstroms; whereas, in another it is approximately 40 angstroms. The boron nitride and metal layers may have sharp interfaces or they may be compositionally graded, as for example by sinusoidally varying the composition throughout the layer pairs. The invention also includes a method for the manufacture of an x-ray dispersive element of the type which comprises a plurality of superposed layer pairs in which a first member of each of the pairs comprises a layer of boron nitride and the second layer comprises a material having an x-ray scattering strength greater than that of boron nitride. The method includes the steps of providing a substrate and depositing the layer pairs in sequence on the substrate by a vacuum deposition process which is characterized in that the layer of boron nitride of each of the layer pairs is deposited by a planar magnetron sputtering process. The layer of higher electron scattering strength material may also be deposited by a planar magnetron sputtering process, and the material may comprise tungsten, nickel, chromium, vanadium, iron, manganese, cobalt, or combinations thereof.
	description	The present application is a divisional of U.S. patent application Ser. No. 13/510,008, filed on May 16, 2012, the text of which is incorporated by reference, which is a National Stage entry under 35 U. S. C. 371 of PCT/JP10/070355, filed on Nov. 16, 2010 and claims priority to Japanese Patent Application No. 2009-260933, filed on Nov. 16, 2009. The present invention relates to a corrosion-resistant structure and a corrosion-preventing method for a high-temperature water system, and particularly relates to the corrosion-resistant structure and the corrosion-preventing method for the high-temperature water system, which can effectively prevent the corrosion of a structural material that constitutes a secondary cooling system of a pressurized-water type nuclear power plant (atomic power generation facility) and can effectively reduce the elution of a ferrous component and the like from the structural material. The pressurized-water type nuclear power station (atomic power generation facility) is a reactor facility which heats pressurized water (light water with high pressure) that is a primary coolant to 300° C. or higher with thermal energy generated by a nuclear fission reaction, boils a light water of a secondary coolant with a steam generator to eventually convert the light water into steam of high temperature and high pressure, and rotates a turbine generator by using the steam to generate an electric power. This pressurized-water type reactor is used for large-sized plants such as a nuclear power station, and small plants such as a nuclear vessel (atomic-powered ship). In various plants that include the above described pressurized-water type atomic power generation facility and have a boiler, a steam generator, a heat exchanger and/or the like, in which high-temperature water circulates, it becomes a big problem that ions elute from the metal of the structural material or the structural material itself corrodes. The elution of the metal ions is a representative phenomenon occurring in the high-temperature water, and the elution causes the corrosion of structural members of pipes and equipments, including the structural material, and eventually gives various influences such as an operational problem and the increase of maintenance frequency, on the plant. In addition, the eluted metal ions from the structural material and the like adhere to and deposit on a surface of the pipes in the system, or a high-temperature site of the steam generator and the like, as an oxide, and there is a possibility that impurities form a highly concentrated state, in a narrow portion such as a crevice portion between a heat transfer tubing and a tube-support-plate in a heat exchanger. The impurities also may form an ion-enriched water having strong acidity or strong alkalinity according to the ion balance, and further cause remarkable corrosion. A phenomenon of corrosion cracking in the structural material is also confirmed which is caused by such a phenomenon and a rise of an electrochemical potential due to the oxide which adheres to the surface. Heat transfer also decreases due to the adhering oxide, and accordingly it is needed to remove the oxide on the structural material by chemical cleaning or the like periodically with a high frequency. On the other hand, there has been a high possibility in recent years that the thickness of a carbon steel pipe decreases due to a wall-thinning phenomenon of the pipe and such an accident that the pipe is ruptured also occurs. Thus, the elution, the corrosion phenomenon and the like of the metal are accumulated with time during a plant operation in a long period of time, and potentially show a possibility of suddenly erupting into a disaster at some point when the accumulated amount has reached to a durable limit. Furthermore, the above described corrosion rate is accelerated depending on a shape of a structural site, and a phenomenon which is difficult to be predicted may occur. For instance, in a piping system in which many equipments such as an orifice and a valve are used, erosion or corrosion is caused by the flow of a fluid of high temperature such as a cooling water which passes through the inner space at a high speed. In order to avoid such a problem, various corrosion mitigation methods including a water chemistry control have been conventionally implemented in various plant systems. For instance, in the secondary cooling system of a thermal power station and a pressurized-water type nuclear power station, such measures are taken as to control a pH in a cooling water by injecting ammonia or hydrazine, thereby decrease the elution of iron from the inside of the system and prevent the inflow of the iron component to the steam generator (Patent Literature 1). Furthermore, in order to eliminate the enrichment of alkaline components in the crevice portion, various water chemistry controls have been implemented in an actual plant, such as the control of an Na/Cl ratio, the control of chloride ion concentration for decreasing an influence of a chlorine ion on corrosion, and the control of dissolved oxygen concentration (Patent Literature 2). In recent years, a water chemistry control method is also adopted which uses improved chemicals such as ethanolamine and morpholine. As described above, various technologies for controlling the water chemistry have been proposed as an improved proposal, in addition to the measures which have been already implemented in the actual plant, such as reductions of the corrosion of pipes, the adhesion and deposition of an oxide and the like, and the enrichment of eluted components in the crevice portion. As for the improvement of the chemicals to be injected, for instance, there is a method of using an organic acid such as tannic acid and ascorbic acid as an oxygen scavenger (Patent Literature 3). In addition, as for the water chemistry control method, there are proposed an operation method of controlling a molar ratio of all cations/SO4 (Patent Literature 2), a method of introducing at least one of a calcium compound and a magnesium compound into feed water to a steam generator for a reactor so that the ion concentration becomes 0.4 to 0.8 ppb (Patent Literature 2), and the like. Thus, the measures of suppressing corrosion and elution by water chemistry control with the use of the chemicals are widely implemented under present circumstances as a measure of preventing the corrosion and elution of a plant structural material. However, such a technology is desired which can operate the plant without controlling a water chemistry of the cooling water by injecting the chemicals, from the viewpoints of the complexity of operation management, an operation cost and the safety. Patent Literature 1: Japanese Patent No. 2848672 Patent Literature 2: Japanese Patent No. 3492144 Patent Literature 3: Japanese Patent Laid-Open No. 2004-12162 A present secondary cooling system of a pressurized-water type atomic power generation facility is operated in a state of having a chemical agent such as hydrazine and ammonium injected therein so as to suppress its corrosion. A new technology is necessary in order to enable the plant to be operated without the injection of the chemicals. Then, an object of the present invention is to provide a corrosion-resistant structure and a corrosion-preventing method for a high-temperature water system, which can easily operate the plant while obtaining an effective corrosion-preventing effect, not by controlling the water chemistry of a cooling water by injecting the chemicals into the structure, but by providing a technology of modifying a surface of a structural material. In order to achieve the above described object, a corrosion-resistant structure for a high-temperature water system according to one embodiment of the present invention has a corrosion-resistant film formed from a substance containing at least one of La and Y deposited on a surface in a side that comes in contact with a cooling water, of a structural material which constitutes the high-temperature water system that passes a cooling water of high temperature therein. The corrosion-resistant film which is formed from the substance containing at least one of La and Y and has deposited on the surface can effectively prevent the corrosion of the structural material, and can greatly reduce the elution of a metal component such as iron from a cooling water contact surface of the structural material. In the corrosion-resistant structure for the high-temperature water system, the temperature of the cooling water of high temperature is preferably 20° C. or higher and 350° C. or lower. The above described corrosion-preventing effect of the corrosion-resistant film which has deposited on the surface of the structural material shows an anticorrosive effect in a wide temperature range from the above described ordinary temperature to an operation temperature of the secondary cooling system of the pressurized-water type atomic power generation facility. Furthermore, in the above corrosion-resistant structure of the high-temperature water system, the substance containing La is preferably at least one La compound selected from La2O3, La(OH)3, La2(CO3)3, La(CH3COO)3 and La2(C2O4)3. Any one of these La compounds shows an excellent anticorrosive effect when being contained in the corrosion-resistant film. In the corrosion-resistant structure for the high-temperature water system, the substance containing Y is preferably at least one Y compound selected from Y(OH)3, Y2(CO3)3, Y(CH3COO)3 and Y2(C2O4)3. Any one of these Y compounds shows an excellent anticorrosive effect when being contained in the corrosion-resistant film, though the effects are different to some extent according to the type. In the corrosion-resistant structure for the high-temperature water system, the structural material (structural member) is preferably at least one structural material selected from a carbon steel, a copper alloy and an Ni-based alloy. Any one of the carbon steel, the copper alloy and the Ni-based alloy can effectively prevent the elution of its metal component even though the above described structural material is any one of them. In the corrosion-resistant structure for the high-temperature water system, the deposition amount of La is preferably 1 μg/cm2 or more and 200 μg/cm2 or less. When the deposition amount of La is in the above described range, a high corrosion-preventing effect can be obtained. On the other hand, even when the deposition amount of La exceeds the upper limit of the above described range, the corrosion-preventing effect results in being saturated. Furthermore, in the above corrosion-resistant structure for the high-temperature water system, the deposition amount of Y is preferably 1 μg/cm2 or more and 200 μg/cm2 or less. When the deposition amount of Y is in the above described range, a high corrosion-preventing effect is obtained. On the other hand, even when the deposition amount of Y exceeds the upper limit of the above described range, the corrosion-preventing effect results in being saturated, similarly to the La compound. In addition, a corrosion-preventing method for a high-temperature water system according to the present invention for preventing a corrosion of a structural material constituting the high-temperature water system through which a cooling water of high temperature passes includes steps of: preparing a corrosion inhibitor containing at least one of La and Y; and depositing a prepared corrosion inhibitor on a surface in a side of the structural material, which comes in contact with the cooling water, and forming a corrosion-resistant film thereon. In the above description, it is preferable to previously subject a surface in a side on which the structural material comes in contact with the cooling water, to any one treatment among machining treatment, immersion treatment in high-temperature water and chemical cleaning treatment, before depositing the corrosion-resistant film. In other words, when a cooling water contact surface of the structural material is previously subjected to the machining treatment such as grinding by a liner or the like, thereby an oxide film and a foreign substance of the surface portion are removed and a newly-formed surface is made to appear, the newly-formed surface can enhance an adhesion strength of the corrosion-resistant film. In addition, it is preferable that the structural material is subjected to the treatment of immersion into a high-temperature water of 200° C. to 350° C., thereby an oxide film of the structural material is formed on the surface of the structural material (substrate, base member) and the corrosion resistant film is formed on the surface of this oxide film. This oxide film further enhances a function of the corrosion-resistant film containing La and Y, and can further enhance the corrosion-preventing effect. Furthermore, when the structural material is previously subjected to a chemical cleaning treatment of cleaning the cooling water contact surface of the structural material with an acid or the like, thereby to remove the oxide and the foreign substance and to make a newly-formed surface appear, the newly-formed surface can enhance an adhesion strength of the corrosion-resistant film, similarly to the above described case of the structural material which has been subjected to the machining treatment. In addition, in the above described corrosion-preventing method for the high-temperature water system, the above described method of depositing the corrosion inhibitor on the surface of the structural material is preferably any one of a spray method, a CVD method, a thermal spray method and an immersion method in which the structural material is immersed into a high-temperature water containing the corrosion inhibitor. The above described spray method is a method of spraying the corrosion inhibitor onto the surface of the structural material with a high pressure gas such as nitrogen gas; the CVD method is a method of chemically vaporizing the corrosion inhibitor, and vapor-depositing the corrosion inhibitor on the surface of the structural material; the thermal spray method is a method of spraying a melted corrosion inhibitor onto the surface of the structural material so as to cover the surface with the melted corrosion inhibitor; and the immersion method is a method of immersing the structural material into the high-temperature water containing the corrosion inhibitor and depositing the corrosion inhibitor on the surface of the structural material. Any method can be more promptly and easily applied to the structural material, in comparison with a conventional operation of controlling a water chemistry of a cooling material. According to the corrosion-resistant structure and the corrosion-preventing method for the high-temperature water system of the present invention, a corrosion-resistant film formed from a substance containing at least one of La and Y is deposited on a surface of a structural material, accordingly the structural material can be effectively prevented from causing corrosion, and an elution of a metal component such as iron from the cooling water contact face of the structural material can be greatly reduced. In addition, the above described corrosion-resistant film shows an excellent corrosion-preventing effect even when the deposition amount is small, and on the other hand, maintains the corrosion-preventing effect for a long period of time because of having high adhesion strength between the corrosion-resistant film and the structural material. Examples of the corrosion-resistant structure and the corrosion-preventing method for the high-temperature water system according to the present invention will be more specifically described hereinbelow with reference to the attached drawings. Firstly, an example of the present invention in which a corrosion-resistant film containing a La compound as a corrosion inhibitor is formed on a structural material will be concretely described below with reference to the attached FIGS. 1A and 1B and FIG. 2. A corrosion-resistant structure for a high-temperature water system according to the present example 1 includes two types of structures, as are illustrated in FIGS. 1A and 1B and FIG. 2. Specifically, FIG. 1A is a view of an example in which a corrosion-resistant film 3 formed from La2O3 has been formed on the surface of a carbon steel that is used as a structural material (substrate, base member) 1 and has a uniform oxide film 2 formed thereon; and FIG. 1B is a view illustrating an example (test piece) in which the corrosion-resistant film 3 formed from La2O3 has been directly formed on a surface of the structural material 1 from which an ununiform oxide film has been previously removed. For information, the oxide film 2 in FIG. 1 A was formed by oxidizing a surface portion of the carbon steel which was used as the structural material 1, in the atmosphere of 150° C. In addition, a carbon steel 1 that was used as the structural material in FIG. 1B had a newly-formed surface exposed thereon which had a smooth and uniform surface roughness, by acid-pickling the surface. Next, a test piece was prepared as a Comparative Example (reference) which was formed only from a carbon steel and did not have an oxide film and a corrosion-resistant film formed thereon, in addition to the two types of the examples in which the corrosion-resistant film was prepared by depositing La2O3 on the carbon steel as was described above. The surface portions of these three types of the test pieces were subjected to a corrosion test under conditions of being immersed in the hot water which contained less than 5 ppb of dissolved oxygen and had a pH of 9.8 at a temperature of 185° C. under a pressure of 4 MPa, for 500 hours. Corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation results are shown in FIG. 2. As is clear from the result illustrated in FIG. 2, it was proved that the corrosion rates were remarkably suppressed in the two types of the test pieces in the example in which the corrosion-resistant film 3 formed from La2O3 was deposited, in comparison with the test piece formed only from the carbon steel. In addition, it was also confirmed that the corrosion-suppressing effect became more remarkable when the oxide film 2 existed. Thus, it was proved that the corrosion-suppressing function for the carbon steel could be effectively shown by La2O3 which was deposited on the surface of the structural material. It is expected according to the above described experimental results that an effect of suppressing general corrosion due to a cooling water and an effect of suppressing a wall thinning phenomenon due to flow-accelerated corrosion can be exhibited by an La-containing compound which has been deposited on a surface of a carbon steel material constituting a secondary cooling system of a pressurized-water type atomic power generation facility. For information, it is confirmed by an experiment that the above described corrosion-preventing effect is not limited to the case in which La2O3 was used as the corrosion inhibitor but the similar effect can be shown also in the case in which La(OH)3, La2(CO3)3, La(CH3COO)3 or La2(C2O4)3 was used as the corrosion inhibitor to be deposited on the surface. Next, an example of the present invention, in which a corrosion-resistant film containing a Y compound as a corrosion inhibitor has been formed on a structural material, will be described below with reference to the attached FIG. 3. A corrosion resistant structure for a high-temperature water system according to the present example has a structure as is illustrated in a schematic view FIG. 1B. Specifically, a surface of a test piece of the present example is a newly-formed surface which is exposed by removing the oxide film with chemicals. Y(OH)3 was used as a corrosion inhibitor. Then, a corrosion-resistant film 3 was formed with the use of a spray coating method of spraying a chemical agent containing Y(OH)3 onto the cooling water contact surface of a carbon steel together with nitrogen gas and depositing the chemical agent. As a result of having examined a state of the formed corrosion-resistant film 3 through SEM observation, it was confirmed that a spot-shaped lump of Y(OH)3 of a micrometric order was formed on a surface portion of the carbon steel. It was proved from this observation result that the deposition uniformity of the corrosion-resistant film 3 was low and the deposition amount of Y(OH)3 was 90 μg/cm2, but that the film thickness considerably dispersed or scattered depending on the site of the carbon steel. Next, a test piece was prepared as a Comparative Example (reference) which was formed only from a carbon steel and did not have an oxide film and a corrosion-resistant film formed thereon, in addition to the example in which the corrosion-resistant film was prepared by depositing Y(OH)3 on the carbon steel as was described above. The surface portions of these two types of the test pieces were subjected to a corrosion test under conditions of being immersed in the hot water which contained less than 5 ppb of dissolved oxygen and had a pH of 9.8 at a temperature of 185° C. under a pressure of 4 MPa, for 500 hours, in a similar way to that in Example 1. Corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation results are shown in FIG. 3. As is clear from the result illustrated in FIG. 3, it was proved that the corrosion rate was suppressed to approximately one-tenth in the test piece in Example 2 in which the corrosion-resistant film formed from Y(OH)3 was deposited, and that an excellent corrosion-preventing effect could be shown, in comparison with the test piece formed only from the carbon steel. Thus, it was proved that the corrosion-suppressing function for the carbon steel could be effectively shown by Y(OH)3 which was deposited on the surface of the structural material. It is expected on the basis of the above described experimental result that an effect of suppressing general corrosion of the structural material and an effect of suppressing a wall thinning phenomenon due to flow-accelerated corrosion are shown when Y(OH)3 has been deposited on a surface of a structural material constituting a secondary cooling system of a pressurized-water type atomic power generation facility. In addition, it is confirmed by an experiment that the above described corrosion-preventing effect is not limited to the case in which Y(OH)3 was used as a corrosion inhibitor, but that the similar effect can be shown also in the case in which Y2(CO3)3, Y(CH3COO)3 or Y2(C2O4)3 was used as the corrosion inhibitor to be deposited on the surface of the structural material. Next, an influence which a difference of an operation temperature (temperature of cooling water) gives on a corrosion-resistant structure will be described below with reference to the following Example 3 and FIG. 4. A corrosion-resistant structure for a high-temperature water system according to the present Example 3 has a structure as is illustrated in a schematic view FIG. 1B. Specifically, a test piece used for the test piece of the present example was in such a state that the surface of a carbon steel before a corrosion-resistant film was deposited thereon had been polished and degreased by a sandpaper with #600, and that an oxide film and a foreign substance had been removed therefrom. Then, the test piece according to Example 3 was prepared by depositing Y(OH)3 onto the surface (newly-formed surface) of this carbon steel with a spray method. A deposition amount of Y(OH)3 in this test piece was set at 50 μg/cm2 by adjustment of a spraying period of time. As a result of having examined a state of the formed corrosion-resistant film 3 through SEM observation, the uniformity was low similarly to that in Example 2. Next, a test piece was prepared as a Comparative Example which was formed only from a carbon steel and did not have an oxide film and a corrosion-resistant film formed thereon, in addition to the example in which the corrosion-resistant film was prepared by depositing Y(OH)3 on the carbon steel as was described above. Then, the surface portions of these two types of the test pieces were subjected to a corrosion test under conditions of being immersed in the hot water which contained 5 ppb or less of dissolved oxygen and had a pH of 9.8 at a temperature in two levels of 150° C. and 280° C. under a pressure of 4 MPa and 8 MPa, for 500 hours, in a similar way to that in Example 1. Corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation result is shown in FIG. 4. As is clear from the result illustrated in FIG. 4, the corrosion amount of the test piece formed only from the carbon steel also decreases under the condition that the temperature is as high as 280° C. This is considered to be because the formed oxide film has high stability because the temperature is high. On the other hand, it is understood that the corrosion rate becomes large when the temperature is 150° C. because the solubility of the oxide film to be formed under the condition of the present test is high, and that the corrosion-suppressing function works due to the deposition of Y(OH)3. Therefore, the corrosion-resistant structure can be applied in such an environment that a cooling water is 20° C. or higher and 350° C. or lower which is an operation temperature of a secondary cooling system of a pressurized-water type atomic power generation facility, in view of the fact that Y(OH)3 is resistant to high temperature. In addition, as is clear from FIG. 4, the corrosion-resistant structure according to the present example is particularly effective in a range of an operation temperature of 150° C. or higher after a deaerator, in a secondary cooling system of a pressurized-water type atomic power generation facility, and it is expected that an effect of suppressing an general corrosion of a structural material and a function of suppressing a wall thinning phenomenon due to flow-accelerated corrosion are effectively shown when a chemical agent containing Y is injected into the system and is deposited on a surface of a structural material. Next, an influence which a difference of a deposition amount of a corrosion inhibitor to be deposited on a surface of a structural material gives on a corrosion amount will be described below with reference to the following Example 4 and FIG. 5. A corrosion-resistant structure for a high-temperature water system according to the present Example 4 has a structure as is illustrated in a schematic view FIG. 1B. Specifically, a test piece used for the test piece of the present Example 4 was in such a state that the surface of a carbon steel before a corrosion-resistant film was deposited thereon had been polished and degreased by a sandpaper with #600, and an oxide film and a foreign substance had been removed therefrom. Then, a large number of two types of test pieces according to Example 4 were prepared by depositing La2O3 or Y(OH)3 onto the surface (newly-formed surface) of this carbon steel with a spray method. For information, a deposition amount of La2O3 or Y(OH)3 was varied and adjusted in a range of 0 to 300 μg/cm2 by adjustment of a spraying period of time. Next, a test piece was prepared as a Comparative Example which was formed only from a carbon steel and did not have an oxide film and a corrosion-resistant film formed thereon, in addition to the example in which the corrosion-resistant film was prepared by depositing La2O3 or Y(OH)3 on the surface of the carbon steel as was described above. Then, the surface portions of these test pieces were subjected to a corrosion test under conditions of being immersed in the hot water which contained 5 ppb or less of dissolved oxygen and had a pH of 9.8 at a temperature of 185° C. under a pressure of 4 MPa, for 500 hours, in a similar way to that in Example 1. Corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation result is shown in FIG. 5. As is clear from the result illustrated in FIG. 5, it was confirmed that the corrosion amount tended to decrease and the corrosion-suppressing effect tended to increase, as the deposition amount of the corrosion-resistant film increased. It was also confirmed that the corrosion-suppressing effect was saturated and the corrosion rates reached approximately a same level, in a range of a deposition amount of 20 μg/cm2 or more. Accordingly, the deposition amount of the corrosion-resistant film is necessary and sufficient to be in the range of 20 to 120 μg/cm2. Here, a deposition amount of the corrosion inhibitor remaining on a surface of the test piece of which the deposition amount had been set to approximately 50 μg/cm2 before the corrosion test was examined after the corrosion test, and as a result, it was confirmed that the deposition amount was 1 μg/cm2 or less. As a result, it was confirmed that the corrosion-preventing effect continued as long as a fixed deposition amount of an La-containing or Y-containing chemical agent was attained in an initial stage of the application, even though the deposition amount was not always kept constant or the deposition amount decreased due to an exfoliation of the deposited chemical agent during an operation period. It is technically difficult to uniformly deposit the present corrosion inhibitor on the surface of the structural material of the secondary cooling system of the pressurized-water type atomic power generation facility so that the deposition amount becomes uniform, and it is anticipated that the deposition amount of the corrosion inhibitor greatly varies according to an influence of a flow of a cooling water, and depending on a temperature of the cooling water and a structure of the high-temperature water system. However, such a technological knowledge is an important premise for the technology that an initial corrosion-preventing effect develops even when the deposition amount of the corrosion inhibitor has greatly varied depending on the site of the structural body as has been described above, and is extremely useful when the technology is applied to an actual apparatus. Next, an influence which a difference between methods of depositing a corrosion inhibitor on a surface of a structural material gives will be described below with reference to the following Example 5 and FIG. 6. A corrosion-resistant structure for a high-temperature water system according to the present Example 5 has a structure as is illustrated in a schematic view FIG. 1B. Specifically, a test piece used for the test piece of the present Example 5 was in such a state that the surface of a carbon steel before a corrosion-resistant film was deposited thereon had been polished and degreased by a sandpaper with #600, and an oxide film and a foreign substance had been removed therefrom. Then, two types of test pieces according to Example 5 were prepared by depositing La2O3 onto the surface (newly-formed surface) of this carbon steel with a spray method or a chemical deposition method of injecting a chemical substance into a high-temperature water and depositing the chemical substance. In the above description, the deposition amount of La2O3 was adjusted to 50 μg/cm2 by adjustment of a spraying period of time or an amount of the chemical agent to be injected into the high-temperature water. Here, the above described chemical deposition method is a method of making a substance to be deposited exist in a fluid, and depositing the substance onto a surface of a structural material by a flow of the fluid. Next, the surface portions of the two types of the test pieces which were prepared by depositing La2O3 on the surface of the carbon steel with different methods as was described above were subjected to a corrosion test under conditions of being immersed in the hot water that contained 5 ppb or less of dissolved oxygen and had a pH of 9.8 at a temperature of 185° C. under a pressure of 4 MPa, for 500 hours, in a similar way to that in Example 1. Then, corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation result is shown in FIG. 6. As is clear from the result illustrated in FIG. 6, the corrosion-resistant film which had been deposited and formed with the chemical deposition method was different from and could be more uniformly deposited than the corrosion-resistant film which had been formed with the spray method, and it was confirmed that the corrosion-resistant film which had been formed with the chemical deposition method had a greater corrosion-rate-suppressing function. It is expected that the deposition of the corrosion-resistant film having high uniformity can be achieved by injecting an La-containing substance into a high-temperature cooling water during an operation of the secondary cooling system of the pressurized-water type atomic power generation facility and by depositing the substance onto the surface of the structural material, and that thereby an effect of suppressing general corrosion and an effect of suppressing a wall-thinning phenomenon due to flow-accelerated corrosion are shown. A similar effect can be shown also when a Y-containing substance has been injected into the high-temperature cooling water. Next, an effect appearing when La(OH)3 or Y2(CO3)3 as other corrosion inhibitors has been deposited on a surface of a structural material will be described below with reference to the following Example 6 and FIG. 7. A corrosion-resistant structure for a high-temperature water system according to the present Example 6 has a structure as is illustrated in a schematic view FIG. 1B. Specifically, a test piece used for the test piece of the present Example 6 was in such a state that the surface of a carbon steel before a corrosion-resistant film was deposited thereon had been polished and degreased by a sandpaper with #600, and an oxide film and a foreign substance had been removed therefrom. Then, two types of test pieces according to Example 6 were prepared by depositing La(OH)3 or Y2(CO3)3 onto the surface (newly-formed surface) of this carbon steel with the use of a spray method. For information, a deposition amount of La(OH)3 or Y2(CO3)3 was adjusted to 50 μg/cm2 by adjustment of a spraying period of time. Next, the surface portions of the two types of the test pieces which were prepared by depositing La(OH)3 or Y2(CO3)3 on the surface of the carbon steel as was described above were subjected to a corrosion test under conditions of being immersed in the hot water that contained 5 ppb or less of dissolved oxygen and had a pH of 9.8 at a temperature of 185° C. under a pressure of 4 MPa, for 500 hours, in a similar way to that in Example 1. Then, corrosion amounts (corrosion rates) were calculated from weight changes before and after the corrosion test of each test piece. The measurement calculation result is shown in FIG. 7. As is clear from the results illustrated in FIG. 7, when the corrosion amounts of the two types of the test pieces which were prepared by depositing La(OH)3 or Y2(CO3)3 on the surface of the carbon steel were compared to each other, the corrosion amounts were not greatly different from each other, but it was confirmed that when the two types of the test pieces were compared to the test piece formed only from the carbon steel illustrated in Examples 1 and 2, the corrosion rates were remarkably suppressed. It was experimentally proved that a great corrosion-preventing effect was obtained by depositing and forming a hydroxide of La or a carbonate of Y on the surface of the structural material as in the above described Example 6. Accordingly, it is expected that an effect of suppressing general corrosion of the structural material and an effect of suppressing a wall thinning phenomenon due to flow-accelerated corrosion are shown also when the hydroxide and the carbonate are deposited on the surface of the structural material in the secondary cooling system of the pressurized-water type atomic power generation facility. According to the corrosion-resistant structure and the corrosion-preventing method for the high-temperature water system of the embodiments of the present invention, a corrosion-resistant film formed from a substance containing at least one of La and Y is deposited on the surface of the structural material, accordingly the structural material can be effectively prevented from causing corrosion, and an elution of a metal component such as iron from the cooling water contact surface of the structural material can be greatly reduced. In addition, the above described corrosion-resistant film shows an excellent corrosion-preventing effect even when the deposition amount is small, and on the other hand, can maintain the corrosion-preventing effect for a long period of time because of having high adhesion strength between the corrosion-resistant film and the structural material. 1 Structural material (carbon steel) 2 Oxide film (Oxide layer) 3 Corrosion-preventing film (La2O3 film, Y(OH)3 film, La(OH)3 film or Y2(CO3)3 film) 4 Cooling water (Coolant)
050009087	abstract	The present invention relates to intermittently introducing, under carefully controlled conditions, an inert gas, into at least the channel head primary coolant water outlet side of steam generators during the drain-down of a nuclear-powered steam generating system. Predetermined quantities of such gas are introduced into open ends of the inverted U-tubes which terminate at the tubesheet in the channel heads to thereby alleviate the propensity for formation of vacuum pockets at the tops thereof, and at the same time to provide that water columns defined severely near their tops by the water within each such tube and collectively near their bottoms by the water extending downward through the steam generator channel head, are not disrupted by the inadvertent formation of a gas/water interface formed in the general vicinity of the tubesheet and resulting from the flooding of the underside thereof with said gas. There exists a dependent and inversely proportional relationship between the pressure of gas introduction and the ratio of pulse time-on to pulse time-off in the instant gas introduction procedure, to thereby effect an optimum ratio of about 1.1 between the volume of nitrogen introduced into and the volume of water removed from such inverted U-tubes.
052895157	claims	1. In a combination of a grid for a nuclear fuel assembly and a plurality of elongated key members, said grid comprising a plurality of elongated straps intersected with each other to define a plurality of grid cells therein, a plurality of pairs of dimples and springs formed on said straps for supporting a plurality of fuel rods, and a plurality of openings which are defined at intersections among said straps, each pair of dimples and springs being disposed in facing relation to each other, on wall sections of said straps, which cooperate with each other to define one of said grid cells, the pair of dimples and springs projecting into the grid cell, and each of said elongated key members being provided for maintaining the springs deflected respectively away from the dimples, the key member being capable of being inserted into said grid cells through said openings along a longitudinal direction of a corresponding one of said straps; the combination further comprising: a deflecting jig capable of being inserted into one of said grid cells, said deflecting jig being in the form of a rod having a diameter capable of being enlarged to urge the spring associated therewith against resilient force of the spring to deflect the spring away from the dimple associated therewith; each of said elongated key members being formed with a plurality of hooks which are spaced a predetermined spacing from each other along a longitudinal direction of the key member, and being rotatable about its axis to cause the hooks of the key member to project from a wall surface of the strap associated with the key member, through the openings, in a direction opposite to the projecting direction of the spring formed on the strap, said key member being movable forwardly in a longitudinal direction of the strap to engage the hooks of the key member with the wall surface of the strap, thereby fixedly mounting the key member to the strap to maintain the spring deflected, and being formed such that when the urging of the spring due to said deflecting jig is released to allow the same to be withdrawn from the grid cell and, subsequently, said fuel rods are inserted respectively into said grid cells, said key member is movable rearwardly to release retention of the springs due to the hooks of the key member thereby bringing the springs into pressure contact with the fuel rods, respectively, and allow said key members to be withdrawn from said grid cells. 2. A combination according to claim 1, wherein the pair of dimples and springs are disposed so as to have a distance therebetween which is larger than a diameter of the fuel rod when the respective springs are maintained deflected by the hooks of the key member. 3. A combination according to claim 1, wherein each of said straps includes a plurality of ribs associated respectively with the springs formed on the strap, each of the hooks on the key member being able to be engaged with a corresponding one of the ribs. 4. A combination according to claim 3, wherein each of the ribs is spaced from a corresponding one of the springs in a direction away from the grid cell associated with the spring. 5. A combination according to claim 4, wherein each of the straps includes a plurality of pairs of ribs, and wherein each spring is located between a corresponding pair of ribs. 6. A combination according to claim 1, wherein said deflecting jig comprises a sleeve divided into a plurality of sleeve pieces and a tapered pin inserted into said sleeve for axial sliding movement along the same.
	summary
H00002356	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention utilizes Rutherford backscatter analysis techniques to measure the energy species content of an intense particle beam (i.e. neutral or ion beam) which is scattered from a target surface. As will be explained hereinafter, the measurement is performed in a manner that yields fast, reproducible results with simple analyses, using well-known parameters. Rutherford backscattering analysis, particularly Rutherford Backscattering Spectroscopy (RBS) has been used to study materials exposed to energetic particles in general (H. Uecker et al, J. of Nucl. Mat. 93 and 94 (1980) 670, and M. Braun et al, J. of Nucl Mat. 93 and 94 (1980) 728) and tokamak plasma ions in particular (R. A. Zuhr et al, J. of Nucl. Mat. 93 and 94 (1980) 127, J. B. Roberto et al, J. of Nucl. Mat. 93 and 94 (1980) 146, W. R. Wampler et al, J. of Nucl. Mat. 93 and 94 (1980), 139). The technique has even been used to study the composition of ion and neutral beams (R. A. Langley et al., J. of Nucl. Mat. 93 and 94 (1980), 390, and A. Pospieszczyk et al, J. of Nucl. Mat. 93 and 94 (1980) 396). In these and all other earlier studies, the material imbedded in the exposed sample is the unknown, and was examined with the Rutherford back-scattering technique utilizing a known Van de Graaff accelerator beam. In the present invention, the target material off of which the Rutherford backscattering is performed, is known, whereas the particle beam which strikes the target material is unknown. That is, in contrast to the established Rutherford backscatter spectrometry technique for analyzing unknown targets using a known particle beam, the present invention uses a known target to determine unknown beam properties, particularly the energy species content of an intense incident neutral beam. Further, conventional RBS techniques require the exposed sample to be removed to a separate facility (i.e. the Van de Graaf accelerator laboratory) for analysis, whereas in the present invention, every component remains in situ. Neither a Van de Graff accelerator nor any other facility is required. Most energetic neutral beam particles incident on a solid target come to rest on the target. However, a small fraction of the incident beam particles collide with nuclei and are reflected out of the target. The recoil energy of these backscattered particles is governed by well-known laws of classical mechanics. Their angular distribution and yield at a particular angle are described by the Rutherford elastic cross section. In particular, beam particles of energy E.sub.0 reflected from the top surface layer of a target recoil with a kinetic energy (KE.sub.0) less than E.sub.0, where the kinematic factor K is given by equation 1 of Table I, wherein m is the incident particle mass, M is the target nucleus mass, and .theta. is the recoil angle, or net angle between the incoming and the outgoing particle, as can be seen with reference to the diagram of FIG. 1. The maximum energy resolution of the backscattered particles is obtained when K is as close to 1 as possible. Hence, for a given beam particle mass (m), the target nucleus mass (M) should be as large as possible, and the detection of backscatter particles should take place as close to a recoil angle .theta. of 180.degree. as is permitted by the detection geometry. The probability that particles entering the target lose energy and interact (i.e., backscatter) with target nuclei at an energy less than E.sub.0, increases as their energy decreases. Hence, the backscattered particles have an energy distribution and a yield which increases with decreasing energy, as can be seen with reference to the yield-versus-energy plot of FIG. 2. This behavior is described approximately by the single collision Rutherford elastic cross-section given in equation number 2 of Table I. In this equation, .sigma. is the cross section Z.sub.1 and Z.sub.2 are atomic numbers of the beam and target species, and E is beam energy. In particular, the backscatter yields from near surface scattering are well-described by the Rutherford cross-section, whereas for scattering from depths far from the surface, the shape and height deviates slowly from the behavior expected from the single collisions due in part to multiple scattering. This can be seen with reference to FIG. 3 wherein the three diagrams appearing above the curve refer to planes of atomic particles forming the near-surface of the target. As shown in FIG. 3, which illustrates the energy yield for a thick target, the backscatter yields from near-surface scattering are well described by the Rutherford cross-section, whereas the shape and height of the backscatter spectrum deviates from this cross-section for scattering from depths which are far from the surface, due principally to multiple scattering events. The preferred embodiment of the present invention will be described with respect to near-surface approximations, although the scope of the present invention covers more rigorous back-scattering analyses as well. Referring again to FIGS. 1 and 2, the energy difference .DELTA.E is defined as KE.sub.0 -E.sub.f, where E.sub.f is given by equation 4 of Table I. The surface approximation of the schematic energy spectrum from a FIG. 3 target is given by equation 4 of Table I, where dE/dX is the rate of energy loss and, where the quantity in parentheses is indicated by the variable S in equation 5 of Table I. Referring now to FIGS. 4 and 5, the height of the energy spectrum for a near-surface approximation of a thick target gives a yield (Y) which is defined by equation 6 of Table I, where D.sup.0 is the number of incident particles, .phi..delta..chi. is the number of target atoms per unit area, .sigma. is the Rutherford elastic cross-section, S is the measured back-scatter energy loss factor as defined in Equation 5, .delta. E is the detector energy channel width, .OMEGA. is the detector solid angle and f is the detection efficiency of the analyzer used to measure the backscattering yield. Substituting .DELTA.x in equation 5, gives an expression for the yield Y in equation 7 of Table I. In the preferred embodiment of the present invention, attention is directed to that portion of the yield curve due to near surface scattering, as found at the knee of the yield curve (See FIG. 5). Focusing attention on the near-surface back-scattering simplifies the energy species analyses and yields acceptably accurate results in many applications. Consider, for example, a deuterium beam with a single species having a yield (Y) due to scattering from the near surface layer, as given by Equation 6. It can be seen that the yield is directly proportional to the number of incident particles (D.sup.0) and several other readily obtainable material characterization and geometric parameters. If a particle beam has several species components, each with the same mass but having different energies, (such as in the case of neutral deuterium beams used for heating fusion reactors plasmas) the backscatter yield of a beam with energy components or species D.sup.0 (E). D.sup.0 (E/2), D.sup.0 (E/3) will be as shown in FIG. 6. The respective yields Y.sub.1, Y.sub.2, Y.sub.3 are shown in Table I as Equation 8-10, having a form similar to that of Equation 6. The ratios of the number of beam particles having energies E to those having one-half energy E/2 is given by Equation 11 of Table I, which follows directly from Equations 8 and 9. Similarly, the ratio of the number of beam particles having full energy E to those having one-third energy E/3 is given by Equation 12 of Table I, which follows from Equations 8 and 10. Note that since the same detector is used to measure the full energy, one-half energy and one-third energy, the detector geometry factor .OMEGA. cancels, and the resulting ratios are independent of the geometrical efficiency. The resulting ratios for the respective species yields are given in terms of the measured surface yields, the respective backscatter energies, an energy-dependent detection efficiency, and a parameter characteristic of the rate of energy loss in the target, which as can be seen with reference to FIG. 7, shows the stopping powers of hydrogen and deuterium in titanium and carbon (curves 7a, 7b, respectively). The near-surface composition of the target is characterized with reference to the graph of FIG. 7, wherein the ordinate expresses stopping power (or the rate of energy loss for given target materials), while the abscissa expresses normalized particle energy in keV/AMU. The energy loss factor (See eq. 5) for a given beam and target can be calculated using the energy loss rates (dE/dX) tabulated in the literature, such as in the article by H. H. Anderson, R. F. Ziegler, The Stopping and Ranges of Ions in Matter, Vol. 3, Pergamon Press, New York (1977). Thus, the species intensities in the particle beam are given simply and accurately in terms of directly measured quantities. In the case of a beam having species with the same energy but differing mass (m) or atomic number (Z), the analysis follows from equations 8-10 in a similar manner. For different masses, the kinematic factor K from equation 1 will not be the same, so the .delta. E and S(E) in equations 8-10 for each mass have to be computed with the same E.sub.o, but with a different K (equations 3-5). Since the Rutherford cross sections also depend on the mass, the ratios in equations 11 and 12 have to include the ratios of these cross sections as computed using equation 2. For different atomic numbers, the K-factors will be the same, but the Z-dependence of the Rutherford cross section will also require their inclusion in equations 11 and 12. Thus, equations 8-10 will be identical in form in both cases, but the different Rutherford cross sections will mean that equations 11 and 12 will have the form of equations 13 and 14 of Table I. The preferred embodiment of the present invention has been described with reference to the near-surface approximation of Equation 6, corresponding to the determination of point "a" in FIG. 3, for example. However, those skilled in the art will appreciate that the present invention also covers more rigorous treatment of yield as a function of energy and D.degree. in particular. These more rigorous techniques would be employed, for example, to determine D.degree. from the area under the yield-energy curve of FIG. 3, as opposed to the linear expression of point a in that figure. Such rigorous techniques will be readily apparent to those having ordinary skill of the art, and will not be set out in the general discussion of the invention presented here. In any event, the individual energy species D.degree. of the several beam components are derived from the yield-energy relationship of the overall beam. A more rigorous approach than that of equation 6 would still involve the same variables as those set out in that equation, but higher-order terms will be included. Once the yield-energy relationship of the beam is determined, the individual species components D.sub.i .degree. can be obtained using such material characterization factors as .sigma.S and .phi., and such geometric factors as .phi..delta.x, .delta.E and .OMEGA..function., all of which are readily determinable by those skilled in the art. Alternatively, numerical, computer-aided analysis of a series of energy yield component curves can be modeled and applied to solve unknown complex systems. The preferred embodiment of the present invention includes a fast ion electrostatic analyzer with a micro-channel plate (MCP) array at its focal plane. The analyzer is described in an article by R. Kaita, one of the inventors of the present invention, and others, in the Review of Scientific Instruments, Vol. 52, No. 12, December (1981) on page 1795. Referring now to FIG. 8, a fast ion electrostatic analyzer 10 is shown having an outer vacuum housing 12. An incident neutral beam 14 enters analyzer 10 through an orifice 16 in the outer vacuum housing 12. The incident beam thereupon passes through a gas-stripping cell 20 where neutral particles are ionized, rendering the particles deflectable by electrostatic deflection plates 24. Helium stripping gas enters cell 20 at inlet 26. According to the voltage applied to electrostatic deflection plates 24, a portion of the incident particles 14 within a specific energy range is directed by the plates 24 onto a microchannel plate array (MCP) 30. The portion of particles 14 not deflected by plates 24 continue in a straight-line trajectory through nickel mesh 36 to a beam dump 40. Vacuum within the housing 12 is maintained by a 1500 liter/second pump (Sargent-Welch Model 3133 C turbomolecular pump) at an orifice 48 near the front of the analyzer, and by two vacuum pumps connected to orifices 52 near the rear of the analyzer. These two pumps are of the 1500 liter/second, Leybold-Heraeus Model NT 1500 turbomolecular pump type. The gas stripping cell 20 and the walls of the vacuum chamber 12 surrounding the stripping cell are made of soft iron, thus providing a double shielding against stray fields of nearby apparatus (e.g. tokamaks), serviced by the neutral beam. In the preferred embodiment, neutral beam experiments were performed on Princeton Plasma Physics Laboratory Poloidal Divertor Experiment machine located in Princeton, N.J. The Poloidal Divertor Experiment (PDX) generated strong electric and magnetic confinement fields representing a source of potential electromagnetic interference with the sensitive analyzer operation. The stripping cell is comprised of one large, long stripping cell, with flow restrictors 60, 62 located at each end. The restrictors are essentially long rectangular tubes that provide a minimum of interference for the energetic particles traveling along linear trajectory 14, but reduce the conductance of the helium stripping gas out of the main stripping chamber. By using one long stripping cell whose length constituted a significant fraction of the flight path instead of many individual cells for each trajectory, the cell design was greatly simplified. Also, signal scattering due to angular scattering by the lower energy ions was presumably increased somewhat by this geometry, but the primary application of this system is to measure ions in the 10-60 keV range where scattering in the cell is small. A pressure difference between the stripping cell 20 which was held at 0.5 mTorr of helium gas, and the rest of the system (which was held between 0.01 and 0.02 mTorr) was maintained using the design pumping capability of 4500 liter/second. The energy of incident neutrals is determined electrostatically in detector 10, as they emerge as ions from stripping cell 20. The ions pass between two cylindrical plates 24 which bend the ions through an angle of 127.degree., an angle chosen to provide a maximum angular focussing in the vertical direction. The plates 24 are shielded from external magnetic fields by a soft iron enclosure (not shown) inside the vacuum chamber 12. Since the chamber walls themselves are also made of soft iron, the deflection plates, like the stripping cell, have a double iron shield. All iron components were plated with 0.013 mm of nickel to protect them against oxidation. After passing through the electrostatic deflection plates 24, the ions strike MCP array 30. This array consists of 4 detectors composed of 30 strips, each 1 cm long and 0.5 cm wide. Since each MCP strip has its own anode electrode, the position at which a particular ion strikes the array is known. This determines the geometry of the trajectories that the ions had to follow, and enables an "imaging" of the plasma from the measured ion distribution. The analyzer can be aimed so that some detectors may see a signal "peak" while others might be looking off center (FIG. 13) at the same time. The individual MCP detectors can be biased to different voltages, providing a spatially variable gain for such situations where the flux varies strongly across the MCP array. The detection method of the preferred embodiment allows a complete backscatter spectrum to be measured as rapidly as every 20 milliseconds. The energy species yields of a neutral beam can be obtained from the spectra by manual calculations (as set forth in an article by H. W. Kugel, R. Kaita, R. J. Goldston, D. D. Meyerhofer, J. T. Kozub, and M. D. Williams, Bull. Am, Phys. Soc. 27, 1049, (October 1982)) or automatically, using data processing equipment which implements the same calculations. A particular feature of the present invention is the use of the aforementioned analyzer to detect particles incident upon the analyzer from up to five different angles (all lying in a horizontal plane) by collecting and amplifying signals from five different sections of the MCP array 30. This allows the analyzer to simultaneously detect particles backscattered from five different horizontal locations spaced-apart across the target, thus providing a measure of the radial distribution of the energy species components which lie in a plane perpendicular to the beam axis. The number of detected angles ("channels") or sections of the MCP array can be increased simply by fabricating more electronics to provide a larger section of the MCP array, thereby giving greater spatial resolution. As mentioned earlier, the MCP array consists of four detectors each with 30 strips, for a total of 120 strips. Each of the five amplifier modules is capable of handling signals from 6 of these strips, so any thirty of them can be monitored simultaneously. Spreading the amplifier modules across the MCP array was quite adequate for obtaining the beam profile data shown on FIG. 12, but if more resolution is required, additional amplifiers could be built to cover additional strips, or the entire analyzer can be moved for different views during subsequent beam pulses. In the preferred embodiment, the entire analyzer pivots horizontally so as to allow a continuous change in the viewing angle. Thus, the entire target can be scanned (in a horizontal plane) to give a continuous measurement of the radial distribution of the beam species components across the beam. Of course, including a larger number of viewing angles obviates the need to pivot the analyzer in order to scan the target. This radial profile is an important measurement for optimizing the beam system performance. The efficiency of plasma heating with neutral beams is dependent on how much full energy component there is and its spatial distribution, so knowing this information is needed to tune the beam for best operation. As an alternative to the fast ion electrostatic analyzer described above, other types of detection devices such as solid state surface barrier detectors, scintillators, and faraday cups could be used. Attenuation of the back-scattered particles, before they are detected, by the residual gas that remains between tokamak plasma discharges might make the technique of the present invention seem impractical, but (for the multi-keV particles produced by present-day neutral beams, at least) this has been confirmed not to be a problem. Furthermore, use of high gain (10.sup.6 -10.sup.7) MCP detectors makes a high back-scattered particle flux unnecessary. The preferred embodiment according to the present invention will be described with reference to the Poloidal Divertor Experiment (PDX) located at the Princeton University Plasma Physics Laboratory (PPPL) in Princeton, N.J. The PDX Tokamak provides an experimental facility for the direct comparison of various impurity control techniques under reactor-like conditions, as explained in an article by D. Meade et al, in "Plasma Physics and Controlled Nuclear Fusion Research 1981" (Proc. 8th Int. Conf., Brussels, 1980), IAEA, Vienna 1, 665 (1981). The principle method employed to raise the temperature of a tokamak plasma to reactor levels will comprise neutral beam injection heating. The PDX neutral beam system consists of four beam injectors. An energetic-ion source accelerates charged particles up to 50 keV. The object is to introduce these energetic neutral particles into the magnetic confining region of PDX, but since charged particles would be deflected by the confining field, they must first be neutralized without loss of energy. This is accomplished in the neutralizer gas cell where most of the ions pick up an electron on the way through the cell. The particles emerge from the neutralizing cell as high energy neutrals, leaving behind low-energy ions. The few ions which pass through the neutralizing cell without undergoing charge exchange are magnetically deflected to an ion dump. The rest of the beam penetrates the intended distance into the magnetic field of the PDX, and is re-ionized by collisions with the plasma already present. The beam particles, no longer neutral but a mixture of energetic ions and electrons, are magnetically trapped, becoming additions to the plasma population. The particles immediately enter into confined orbits along which further collisions take place. The result is a gradual slowing down of the fast ions with attendant heating of the background plasma. Four neutral beam lines can inject up to seven megawatts of neutral beam power for 300 milliseconds. As can be seen with reference to FIG. 9, the injection angle of each neutral beam relative to the radial line is 9.degree., coincident with the direction of the plasma current. The neutral beams, if not absorbed by an intervening plasma, fall incident upon the inner wall 100 of the PDX Tokamak 110. The inner wall protective plates 120, provided for protection of the inner wall 100, are designed to absorb 8 megawatts of neutral deuterium beam power at maximum power densities of 3 kW/cm.sup.2, for pulse lengths of 0.5 seconds. The protective plate design consists of a tile and mounting plate structure. The mounting plates are water-cooled to allow short duty cycles and beam calorimetry. While several material combinations for the tiles were proposed, titanium-carbide-coated graphite was selected as the tile material. The design of the PDX Tokamak wall armor and inner limiter system is described in an article by H. W. Kugel, an inventor of the present invention and M. Ulrickson, as published in J. Nucl. Tech./Fus. 2, 712, (1982). Accurate calibration of neutral species energy yields [D.sub.0 (E), D.sup.0 (E/2), D.sup.0 (E/3)] injected during plasma heating experiments is important for diagnosing the conditions under which high temperature plasmas can be achieved. The actual neutral species yields that are present during heating operations may differ from species yields measured off-line on test stands (cited, for example, in an article entitled, "Determination of Species Yield of Ion Sources Used for Intense Neutral Beam Injection", C. C; Tsai, C. F. Barnett, H. H. Haselton, R. A. Langley, and W. L. Sterling, Oak Ridge National Lab Technical Memo ORNL/TM 8360, August, 1982). In the preferred embodiment, the species yield of one neutral beam injection system in the PDX machine, (the NW or 45.degree. neutral beam injection system) was measured under operating conditions, in-situ, using the electrostatic analyzer 10 described above. The analyzer detected beam particles Rutherford-backscattered from the "thick" target of PDX inner wall armor 120, in the absence of the plasma in the PDX machine 110. Beams of 25-47 keV D.sup.0 were Rutherford-backscattered at angles 135.degree. from the TiC inner wall armor 120 of the PDX machine 110. Measurements were performed with and without the PDX toroidal magnetic fields. Data were obtained at five horizontal detection angles simultaneously, thereby allowing species measurements to be made across the beam 14. Complete energy scans were made every 20 milliseconds during the beam pulse. A range of operating conditions were studied. Utilizing the setup described immediately above, a typical backscatter spectrum, such as that shown in FIG. 10, was obtained every 20 milliseconds for a 47 keV D.sup.0 beam incident near beam center. FIG. 11 shows a plot of the percentage of neutrals injected versus horizontal distance from the beam center, in centimeters. FIG. 12 shows the ratio of the neutral full energy component to the half energy component, versus horizontal distance from beam center. A solid line, designated by numeral 140, represents a gaussian least-squares-fit to the beam power density profile as measured by an array of thermocouples located on the inner wall armor of the PDX machine. FIG. 13 shows a graph of backscatter signal amplitude (Y) from the full energy component versus horizontal distance across the beam. Dashed line 13a and solid line 13b are the typical limits of the power profiles measured with an array of thermocouples. TABLE I ______________________________________ ##STR1## (1) DIFFERENTIAL RUTHERFORD CROSS SECTION ##STR2## (2) ENERGY DIFFERENCE .DELTA.E .DELTA.E = KE.sub.o - E.sub.f (3) ##STR3## ##STR4## SURFACE APPROXIMATION ##STR5## (4) .DELTA.E = S.DELTA.X (5) THE YIELD (Y) IS Y = .OMEGA.f(D.sup.o .sigma..sub.p .delta.X) (6) SUBSTITUTING FOR .delta.X USING EQ. 5 ##STR6## (7) ##STR7## (8) ##STR8## (9) ##STR9## (10) ##STR10## ##STR11## (11) ##STR12## (12) ##STR13## (13) ##STR14## ##STR15## (14) ##STR16## ______________________________________
044877110	summary	BACKGROUND OF THE INVENTION In the PUREX process ("PUREX" is an acronym for "plutonium-uranium recovery by extraction"), waste reprocessing facilities dissolve used fuel from nuclear reactors in nitric acid. The uranium and plutonium are extracted with an organic solvent and the remaining aqueous phase is frequently neutralized with sodium hydroxide to permit storage in carbon steel tanks. Because this PUREX waste is radioactive, yet has no commercial utility, it must be safely disposed of such as by immobilization in glass at a vitrification facility. The quantity of PUREX waste at some waste reprocessing facilities is too small to justify the cost of constructing a vitrification plant at the reprocessing facility, which means that the PUREX waste must be transported to a central vitrification facility. However, because the PUREX waste is a radioactive liquid it cannot be transported due to the danger of spillage in route. Evaporation of the water in the PUREX waste would produce a fine powder which also cannot be transported because of the danger that any container in which the powder is placed may break open, permitting the wind to disperse the powder. Thus, the waste can only be transported in the form of a solid having a particle size large enough to prevent air dispersion. SUMMARY OF THE INVENTION We have discovered that a cinder aggregate can be made from PUREX waste by adding de-alcoholated alkoxides to it and heating the resulting mixture. The cinder can be safely transported as it is not air dispersable. Once the cinder is at the vitrification facility it can be easily disintegrated in ammonium hydroxide. After the ammonia has been removed with heat, the resulting slurry is entirely compatible with present vitrification processes. The process of this invention is relatively simple and requires the addition of only de-alcoholated alkoxides to the waste. It eliminates the need for high temperatures which require expensive furnaces, high energy costs, and which may volatilize radioactive components of the waste. PRIOR ART U.S. Pat. No. 4,020,004 discloses a conversion of radioactive ferrocyanide compounds to immobile glass by fusion together with sodium carbonate and a mixture of basalt and boron trioxide, or silica and lime. U.S. Pat. No. 4,202,792 discloses mixing liquid nuclear waste with glass formers to obtain a borosilicate glass compound. U.S. Pat. No. 4,224,177 discloses leaching a glass rod containing nuclear waste in a 3N hydrochloric acid solution and 15 to 20 percent aqueous ammonium chloride solution. U.S. Pat. No. 4,234,449 discloses mixing a radioactive alkali metal with particulate silica in order to make a glass for storing the radioactive material. U.S. patent application Ser. No. 272,852 filed June 12, 1981 by J. M. Pope et al. entitled, "Alcohol Free Alkoxide Process for Containing Nuclear Waste," discloses the containment of nuclear waste in an alcohol-free mixture of alkoxides which are converted to a glass. DESCRIPTION OF THE INVENTION The accompanying drawing is a block diagram illustrating a certain presently preferred embodiment of the process of this invention. In the drawing there are two canyon areas 1 and 2 indicated by the dotted lines; the blocks within the canyon areas indicated that those processes are conducted under radioactive containment procedures. In the first step of this invention, the PUREX waste is concentrated in block 3 as, for example, by evaporation, producing a clean water discharge 4. In a separate step, alkoxides are mixed in block 5 and heated to remove the alcohol which is already present as well as the alcohol which is formed in the reaction. The mixed and de-alcoholated alkoxides are mixed with the concentrated PUREX waste in block 6 and that mixture is then sent to block 7 where the water is evaporated and the cinder is formed by heating. The packaged cinders are then shipped to a vitrification center and eventually enter block 8 where they are decomposed and leached with ammonium hydroxide. The resulting slurry is heated to recover the ammonia in block 9 which is recycled in line 10. The remaining slurry is sent to the vitrification facility in line 11. The starting material for the process of this invention is neutralized PUREX waste which is produced in a nuclear fuel reprocessing facility. In the PUREX process spent nuclear fuel is dissolved in nitric acid and the uranium and plutonium is extracted with an organic solvent. The remaining aqueous phase is neutralized with sodium hydroxide which produces a waste product containing about 20 to about 30 percent total solids of which at least about 15 percent is sodium, the remainder being nitrate, hydroxide, radionuclides, iron oxide, and other compounds. In the first step of this invention, the neutralized PUREX waste is concentrated to about 30 to about 40 percent solids. Concentration of the waste makes it easier to work with as less fluid must be handled. However, if the concentration is greater than 40 percent it becomes difficult to pump. Concentration can be accomplished by heating to evaporate the water. In a separate step, it is necessary to prepare the solidification material. The solidification material is prepared by mixing such alkoxides of silicon, boron, and aluminum as are necessary, with alcohol then water, followed by distillation of the alcohol. These alkoxides have the general formula Si(OR).sub.4, B(OR).sub.3, and Al(OR').sub.3 where R is alkyl to C.sub.10 and R' is hydrogen or R. The R group is preferably methyl as it is the least expensive and it does not produce a water-alcohol azeotrope as some of the higher R groups do. The R' group is preferably hydrogen as that is less expensive. It is preferred that all the R groups be the same for simplicity of operation. For the same reason it is also preferred that the alcohol used in this mixture be the same alcohol that is condensed out of the alkoxides. The production of the solidification material from alkoxides is a known process which is fully described in U.S. patent application Ser. No. 27,852 filed June 12, 1981 by J. M. Pope et al. entitled, "Alcohol Free Alkoxide Process for Containing Nuclear Waste," herein incorporated by reference. Briefly, the preparation involves the initial addition of the alcohol to the alkoxide in a mole ratio of alcohol to alkoxide of about 0.5 to about 3, followed by water in a mole ratio of water to alkoxide of about 3 to about 6, though it is also possible to prepare the solidification material using variations of this process. The mixture of the alkoxides produces a colloid. In the next step of this invention, the alcohol is evaporated from the colloid. This is accomplished by simply heating to the boiling point of the alcohol until evolution of the alcohol ceases. The alcohol that is volatilized is both the alcohol that is initially added and the alcohol that is condensed out when the alkoxide polymerizes as indicated in the following general equation where M is a metal such as silicon, boron, or aluminum: EQU M(OR).sub.n +H.sub.2 O.fwdarw.M(OH).sub.n +nROH.uparw. In the next step of this invention, the colloid is mixed with the concentrated PUREX waste. Because the waste may already contain some aluminum, boron, or silicon, the quantity of aluminum, boron, or silicon alkoxide in the solidification material must be adjusted to take into account the amount of these elements which are already present in the waste. Thus, the composition of the solidification material should be adjusted so that the resulting mixture of the concentrated PUREX waste and the prepared solidification material has a composition of about 0.001 to about 1 percent (all percentages herein are by weight) aluminum hydroxide (Al(OH).sub.3), about 5 to about 15 percent silica (SiO.sub.2), and about 1 to about 3 percent boric oxide (B.sub.2 O.sub.3), the remainder being water and the other elements and compounds which were in the concentrated PUREX waste. We have found that if less aluminum hydroxide is present, the resulting cinder will not stick together and form a coherent solid and if more aluminum hydroxide is present the resulting cinder will be so glassy that it will be difficult to leach and disintegrate it. If less silica is present, a powder also results and if more is present it is difficult to leach the cinder. The boric oxide has the reverse effect, so that if less is present the cinder cannot be leached easily and if more is present a powder is produced. For these reasons, the preferred concentration of aluminum hydroxide is about 0.001 to about 0.002 percent, the preferred concentration of silica is about 5 to about 10 percent, and the preferred concentration of boric oxide is about 1.5 to about 2.5 percent. In the next step of the process of this invention, the mixture of concentrated PUREX waste and prepared solidification material is heated to about 400.degree. to about 700.degree. C. which evaporates all the water present and reduces the solids to a cinder. Heating to a lower temperature tends to produce a powdery material and heating to a higher temperature tends to produce a cinder which is not leachable or readily disintegratable. For this reason, the preferred temperature range is about 550.degree. to about 650.degree. C. Once the cinders have been produced they can be safely packaged and transported by rail, truck, or other means to a vitrification center where they are processed for permanent containment in glass. At the vitrification center, ammonium hydroxide is added to the cinders which disintegrates their structure, producing a powder, and leaches out the sodium and boron. Ammonium hydroxide is used because the ammonia is recoverable and reusable and it does not add to the quantity of the volume of the waste. The ammonium hydroxide is produced by adding ammonia to water; it typically has a concentration of about 10 to about 29 percent ammonia because less than 10 percent requires too long of a leaching time and 29 percent is the saturation level of ammonia in water. After the ammonia leaching has been completed, the slurry is heated to volatilize the ammonia, which is recovered and recycled. The sodium is then removed from the slurry by conventional, known processes and the slurry then enters the glass vitrification process without further modification. The glass vitrification process is a known procedure, fully described in the literature.
049892266	claims	1. A device for directing electromagnetic radiation comprising a substrate having first and second sides and corresponding oppositely facing first and second surfaces, said substrate further having a predetermined pattern of areas on said second side from which substrate material has been removed, and a stress-producing film of material coated on at least one of the surfaces of the substrate, wherein said film in combination with said areas on said second side from which substrate material has been removed, bends said substrate to a desired curvature so that said first surface reflects electromagnetic radiation. 2. The device of claim 1 further including a coating of reflective material overlying said first surface. 3. The device of claim 1 further including a plurality of layers of x-ray radiation reflective films. 4. The device of claim 1 wherein said first surface is polished to reflect electromagnetic radiation. 5. The device of claim 1 wherein the second side of the substrate is formed with a series of alternating grooves and ribs arranged generally parallel to one another.
052788814	description	DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a given quantity of aluminum is, as a main component, added to an Fe-Cr-Mn alloy. Furthermore, practical minor elements are added to the alloy, with their quantities restricted to the degree which does not deteriorate the effect of the addition of aluminum. As a result, an alloy, in which the concentration of chromium contained at grain boundaries is not lowered or the same is raised in a neutron irradiation environment, was attained. Functions of components of the alloy according to the present invention and capable of preventing lowering of concentration of chromium at grain boundaries will be described below. In general, as for the change in concentration of elements in the vicinity of grain boundaries due to irradiation of high-energy particles such as neutrons, electrons and ions, the number of elements having relatively large sizes with respect to the average size of atoms contained in an alloy is reduced at grain boundaries. On the other hand, elements having relatively small sizes gather at grain boundaries. Details of the above-described phenomenon are as follows. During movement of point defects, atomic vacancies and interstitial atoms, generated in a material due to irradiation, diffuse to grain boundaries by the same quantity, and the grain boundaries acts as the sink place at which the point defects disappear, and elements the size of which is larger than the average size of the atoms contained in the alloy interact with the atomic vacancies so that the elements are substituted by the atomic vacancies. As a result, the elements having the large size move in the direction opposite to grain boundaries into which the atomic vacancies are diffused. Therefore, their concentration is lowered at grain boundaries. The elements the size of which is smaller than the average size of the atoms contained in the alloy interact with the interstitial atoms so that the elements having the small size are moved together with the interstitial atoms to grain boundaries. As a result, their concentration is raised. Thus, the concentration of dissolved atoms is changed in the vicinity of grain boundaries due to irradiation of high-energy particles such as neutrons. Actually, referring to FIGS. 2 and 4, the concentration of chromium the size of which is larger than the average size of atoms contained in the alloy is lowered. Therefore, the inventors of the present invention found a principle to relatively reduce the size of chromium atom with respect to the average size of atoms contained in an alloy by enlarging the average size of the atoms. In order to realize this, the inventors of the present invention have found a fact that it is effective to add aluminum as a result of a variety of examinations about the addition of elements having large element size and which can be soluble. Furthermore, since it was considered effective to obtain the above-described effect by enlarging the quantity of manganese, a variety of alloys having high manganese content were examined by electron-irradiation. However, if the manganese content is high, a multiplicity of precipitates containing a large quantity of manganese are formed within crystal grains. Therefore, it was impossible to prevent lowering of the density of chromium at grain boundaries by controlling substantially only the quantity of manganese. In the alloy according to the present invention, the addition of aluminium performs a important role for preventing lowering of the density of chromium at grain boundaries due to the above-described function. Therefore, aluminum in a solid solution state must be added by a quantity exceeding a predetermined quantity. It is preferable that components made of the present alloy be subjected to a solution treatment at 1000.degree. C. to 1200.degree. C. for 15 to 60 minutes. Furthermore, it is also preferable that the components be subjected to a plastic working of 30% or lower reduction ratio. If the reduction ratio of the plastic working exceeds 30%, decrease of elongation of the alloy becomes excessive. It is preferable that an ingot of the alloy be subjected to hot working at 1000.degree. C. to 1150.degree. C. so as to make it the final material before subjected to the solution treatment. On the other hand, in the case where the Fe-Cr-Mn alloy is used as the structural material, proper mechanical strength, corrosion resistance, oxidation resistance and swelling resistance are required. A variety of actual elements added for the purpose of realizing the above-described requirements must be restricted to the quantity which does not deteriorate the effect of addition of aluminum. Therefore, the composition of the alloy according to the present invention is restricted as follows; Al; In order to prevent depletion of chromium atoms at grain boundaries due to irradiation of particles such as neutrons, the quantity of addition of aluminum must be 2% (weight percent to be common hereinafter) or more. If it exceeds 12%, precipitations of coarse aluminum compounds may cause excessive brittleness. Furthermore, cracks take place at hot working and cold working. Therefore, the range of addition of aluminum is determined to be 2% or more to 12% or less, preferably 3 to 6%, more preferably 4.5 to 6%. Mn; Manganese must be added by 5% or more in order to improve the effect of aluminum. In a case where the alloy according to the present invention is mainly in a ferritic structure and in a case where it is mainly an austenitic structure, coarse precipitations of manganese compounds are generated and excessive brittleness takes place if the content exceeds 40%. Therefore, the range of manganese content is determined to be 5 to 40%, preferably 5 to 10% or 20 to 30%. If the alloy containing 10 to 20% of manganese is heated to 450.degree. C. to 600.degree. C., impact value of the alloy is reduced. Cr; In order to maintain an excellent corrosion resistance, the content must be 5% or more. If it exceeds 18%, precipitations may be formed in association with aluminum. Furthermore, .sigma.-phase may be formed, and the alloy thereby become brittle. Therefore, it is determined between 5 and 18%. It is preferable that the content be 7 to 12% since excessive brittleness due to forming of .sigma.-phase takes place at high chromium content in a case where the alloy according to the present invention, further preferably 12 to 18% in order to improve corrosion resistance in the case where the alloy according to the present invention is an alloy including austenite phase. Si; It is effective to add silicon by 0.01% or more for the purpose of improving oxidation resistance. If it exceeds 5%, a variety of precipitates are formed in association with Ti, Zr, Ta, N (nitrogen), Ni and/or the like. Therefore, the effect of the addition of silicon may be lost. Furthermore, .sigma.-phase can be easily formed in association with Fe and/or Cr, causing brittleness to take place easily. Therefore, the range of addition of silicon is determined between 0.01 to 5%, preferably 0.1 to 2%. Ti; It is effective to add titanium by 0.01% or more for the purpose of improving oxidation resistance of the alloy according to the present invention. If the content exceeds 1.0%, coarse precipitates are induced by an irradiation with silicon and the like, causing brittleness to be made excessive. Therefore, the quantity is determined between 0.01 to 1.0%. In a case of the alloy of mixed structure of austenite and ferrite containing nickel according to the present invention, titanium must be added by 0.1% or more for the purpose of maintaining swelling resistance. If the quantity exceeds 0.4%, coarse precipitates are induced by irradiation with C (carbon), N (Nitrogen), silicon and the like, causing brittleness to be made excessive. Furthermore, its weldability may be deteriorated excessively. Therefore, the range of the addition of titanium is determined between 0.1 and 0.4%. Zr, Hf, Nb and Ta; These elements must be added by a quantity with which Ti equivalent =(0.53 Zr+0.27 Hf+0.52 Nb+0.26 Ta) becomes 0.1% or more for the purpose of maintaining an excellent swelling resistance in the case where the alloy according to the present invention is a safety mixed structure of austenite and ferrite containing nickel. If the content exceeds 0.4%, brittleness resistance and weldability excessively deteriorate because of the same reason in the above-described case of titanium. Therefore, one or more type of the above-described elements must be added such that Ti equivalent becomes 0.1 to 0.4%. Zirconium is an element for improving high temperature strength in the alloy according to the present invention having ferritic structure. It is effective to add Zirconium by a quantity of 0.01% or more of Ti equivalent. If the quantity exceeds 0.4%, it is not preferable because of the same reason as the above-described case. B; It is effective to add boron by 0.003% or more for the purpose of improving grain boundary strength, facilitating the fining of the crystal grains and improving ductility at high temperatures. Boron is an element which generates He as a result of a reaction .sub.5 H.sup.10 +.sub.o n.sup.1 .fwdarw..sub.2 He.sup.4 +.sub.3 Li.sup.7 due to irradiation of thermal neutrons. Therefore, brittleness of grain boundaries due to generation of He (helium) becomes excessive under the neutron irradiation environment if the quantity exceeds 0.1%. Therefore, it is preferable that boron be added by 0.1% or less. P; Since the addition of phosphor by 0.01% or more causes swelling resistance to be improved, phosphor may be contained. However, the quantity exceeds 0.08%, brittleness becomes excessive. Therefore, it is preferable that the quantity be 0.08% or less. Mo; It is preferable for increasing mechanical strength that molybdenum be added. If the quantity of the addition of molybdenum exceeds 4.0%, .sigma.-phase and Laves phase can be formed excessively, causing brittleness. Therefore, the upper limitation of addition of it is determined to be 4.0%. C and N; It is effective to respectively add C (carbon) and N (nitrogen) by 0.01% or more for increasing mechanical strength. If C and N are respectively added by 0.3% and 0.5%, brittleness becomes excessive due to the forming of coarse nitrides and carbides. Therefore, it is determined that N is added by 0.001 to 0.3% and C is added by 0.001 to 0.5%, preferably C is added by 0.01 to 0.15% and N is added by 0.01 to 0.15%. Ni; It is effective for a purpose of improving ductility to add nickel so that Ni equivalent =(Ni +0.5 Mn +30 C +26 N) becomes 9% or more substituting by one or more element selected from a group consisting of Mn, C and N, preferably 15% or less, further preferably 2 to 15%. In the above-described range of addition of the practical elements, the effect of prevention of chromium depletion at grain boundaries induced by irradiation high-energy particles such as neutrons due to adding aluminum cannot be hindered. Furthermore, the addition of aluminum may also be effective to maintain good oxidation resistance of the alloy according to the present invention. In addition, in the case where content of oxygen is high in the alloy according to the present invention, dispersion strengthening can be realized as a result of forming of alumina. The similar strengthening may be realized by zirconium contained in the alloy according to the present invention. EXAMPLE 1 FIG. 1 is a graph which illustrates the change in the composition of an alloy according to the present invention in the vicinity of grain boundaries by electron irradiation, the alloy being composed by adding 4.8 wt% of aluminum to an alloy composed of 0.01% of C, 10% of Cr, 0.3% of Si, 5% of Mn and the balance of Fe (by weight percent). The above-described irradiation was performed in such a manner that electrons are irradiated simulating the irradiation of neutrons at temperature of 723K to a dose of 10 dpa, where 1 dpa corresponds to the quantity of irradiations of neutrons of about 1.times.10.sup.21 n/cm.sup.2. The composition is not changed in the vicinity of grain boundaries before electrons are irradiated. Lowering of the density of chromium at grain boundaries is prevented by the above-described irradiation. On the contrary, the density of chromium can be raised by about 30% in comparison to the state before the irradiation (the same concentration level as that in the matrix). The alloy according to this example was subjected to hot forging at 1150.degree. C. after vacuum melting. Then, it was subjected to a solution treatment at 1050.degree. C. to 1150.degree. C. before repeatedly subjected to rolling and annealing. Then, it was subjected to a solution treatment at 1150.degree. C. for 15 minutes as the final processing, the solution treatment being a treatment in which it was heated before cleaned with water. FIGS. 2 and 4 are graphs which illustrate a comparative alloy manufactured by a method similar to the above-described preparing process, in which the concentration of chromium at grain boundaries was lowered due to irradiation of electrons is illustrated. FIG. 2 illustrates the change in composition in the vicinity of a grain boundary when an Fe - 10 Cr - 3 Mn alloy was irradiated with electrons. Referring to this drawing, an alloy, the composition of which is similar to the alloy shown in FIG. 1 and in which no aluminum was added, was irradiated with electrons. The electrons irradiation conditions were the same as those in the case shown in FIG. 1. As is apparent from the above, the concentration of chromium was lowered at grain boundaries. Therefore, it can be understood that the addition of aluminum prevents the lowering of the concentration of chromium at grain boundaries (see FIG. 1). FIG. 3 is a graph which illustrates the results of irradiating, with electrons, a Fe - 10 Cr - 22 Mn alloy of the present invention which is composed of four basic elements of Fe, Cr, Mn and 3.0 wt% of aluminum. In this alloy, the quantity of chromium was lowered by 1 wt% in at a grain boundary, but the chromium depletion is very low so that the example concerns this invention. FIG. 4 is a graph which illustrates the change in the composition in the vicinity of a grain boundary when JIS SUS316L steel, which is a conventional steel for use in a core portion of a light-water nuclear reactor, was irradiated by electrons at 723K up to 30 dpa. As is shown, the concentration of chromium was lowered at a grain boundary, while nickel concentration was raised in the same portion. EXAMPLE 2 Table 1 shows the chemical composition (by weight percent) of alloys (Nos. 1 to 7) according to the present invention and comparative alloys (Nos. 8 to 10). FIG. 5 is a graph which illustrates the results of the change in concentration of chromium in the vicinity of a grain boundary when the alloys shown in Table 1 were irradiated with electrons, the examination being made by using an energy dispersion type X-ray spectrum analyzer. The above-described alloy were manufactured by the same method as those according to the Example 1. Irradiation was performed by employing an electron irradiation simulating neutron irradiation at 723 K to a dose of 10 pda (which corresponds to 10.sup.22 n/cm.sup.2 in neutron irradiation). In any one of the alloys, there is no concentration difference of chromium between at a grain boundary and within grains before irradiation. However, concentration of chromium at a grain boundary was raised due to irradiation (Nos. 1 and 2) or lowering of concentration of chromium at a grain boundary was prevented (No. 3). On the other hand, in the alloys (Nos. 4 and 5) of the present invention containing 20% or more of manganese, although concentration of chromium at a grain boundary was slightly lowered as a result of addition of aluminum by the same quantity, the quantity of lowering was considerably reduced to 1% or less. The comparative alloys Nos. 8 to 10 displayed the lowering of the concentration of chromium by 2% or more. According to this example, nickel was contained as unavoidable impurity. The alloy Nos. 1 to 3 and 6 are alloys each having a complete ferritic structure. Each of the alloys Nos. 4, 5 and 7 has about 3% area of residual austenite, while each of the comparative alloys Nos. 8 to 10 has a complete austenitic structure. TABLE 1 __________________________________________________________________________ (wt %) Change in the concentration of CR at grain No. C Si Mn P S Ni Cr Al N O boundaries __________________________________________________________________________ Alloy according to the present invention 1 0.002 <0.01 5.06 0.003 0.004 0.01 10.29 4.21 0.0012 0.0004 .circleincircle. 2 0.003 <0.01 9.88 0.004 0.005 0.01 10.08 4.39 0.0024 0.0002 .circleincircle. 3 0.005 <0.01 15.03 0.003 0.007 0.01 10.22 4.53 0.0018 0.0004 .largecircle. 4 0.003 <0.01 22.77 0.003 0.008 0.01 10.07 4.44 0.0020 0.0004 .DELTA. 5 0.004 <0.01 24.73 0.003 0.009 0.01 9.85 4.27 0.0024 0.0003 .DELTA. 6 0.003 <0.01 5.18 0.003 0.004 0.01 10.15 2.01 0.0014 0.0004 .largecircle. 7 0.003 <0.01 25.50 0.003 0.005 0.01 10.09 2.09 0.0020 0.0003 .largecircle. Comparative alloy 8 0.103 <0.01 15.20 0.003 0.003 0.01 10.07 0.03 0.0018 0.0112 X 9 0.002 <0.01 20.41 0.003 0.005 0.01 10.13 0.10 0.0019 0.0097 X 10 0.002 <0.01 25.43 0.004 0.006 0.01 10.08 0.08 0.0013 0.0125 X __________________________________________________________________________ (.circleincircle.: raised, .largecircle.: no change, .DELTA.: lowered by 1% or less, X: lowered by 2% or more) EMBODIMENT 3 Table 2 shows, together with a comparative alloy (No. 5), the chemical composition of each of the alloys (Nos. 1 to 4) which contain Si and/or Ti according to the present invention. Table 2 also shows the change in concentration of chromium at grain boundaries due to electron irradiation performed similarly to that performed in Embodiment 1. In the case where Si and/or Ti is contained, depletion of chromium at grain boundaries due to irradiation was prevented by addition of aluminum. According to this example, C and N were contained as unavoidable impurities. The alloys according to this example are alloys having ferritic structure. TABLE 2 __________________________________________________________________________ (wt %) Change in the concentration of Cr at Alloy No. C Si Mn Cr Al Ti N grain boundaries __________________________________________________________________________ Alloy according to the present invention 1 0.01 0.4 10.03 10.92 4.41 -- 0.001 .circleincircle. 2 0.01 -- 10.12 10.14 5.48 0.20 0.002 .circleincircle. 2 0.01 0.3 9.87 10.02 4.50 0.11 0.002 .circleincircle. 4 0.01 0.4 18.04 10.01 4.33 0.28 0.001 .largecircle. Comparative alloy 5 0.01 0.3 10.53 10.25 -- 0.24 0.001 X __________________________________________________________________________ (Fe; the balance) .circleincircle.; raised due to irradiation .largecircle.; concentration was not lowered X; concentration was lowered EMBODIMENT 4 Table 3 shows, together with comparative alloys (Nos. 7 to 10 and Nos. 15 and 16), the alloys (Nos. 1 to 6, Nos. 11 to 14 and Nos. 17 to 20) according to the present invention. Table 3 also shows the change in concentration of chromium at grain boundaries due to the irradiation performed similarly to that performed in Embodiment 1. The alloys (Nos. 1 to 6) according to the present invention have a mixed structure of austenite and ferrite or ferrite, and one or more elements selected from a group consisting of Si and Ti are contained by a predetermined quantity. The alloys (Nos. 11 to 14) further contain one or more elements selected from a group consisting of Zr, B and P by a predetermined quantity. In the above-described alloys, the addition of aluminum by a quantity of 2.0 wt% or more is effective to prevent lowering of concentration of chromium at grain boundaries due to irradiation. All of the alloys (except for Nos. 7 to 10) shown in Table 3 are alloys each having a mixed structure of ferrite and austenite including ferrite by about 10 to 25 vol% or having ferrite. The quantity of ferrite in the mixed structure was 10 to 25% in area. TABLE 3 __________________________________________________________________________ (Fe: the balance) (wt %) Change in the concentration of cr at Micro Alloy No. C Si P Mn Cr Al Ti Zr N B grain boundaries Structure __________________________________________________________________________ Alloy according to the present invention 1 0.27 2.1 0.001 9.2 7.5 5.3 0.3 -- 0.01 -- .circleincircle. Ferrite & Austenite 2 0.008 0.3 0.008 13.2 10.2 5.5 0.3 -- 0.20 -- .largecircle. Ferrite 3 0.10 0.3 0.010 8.5 11.2 5.2 0.3 -- 0.12 -- .circleincircle. " 4 0.09 0.4 0.009 15.8 9.3 5.8 0.3 -- 0.21 -- .largecircle. " 5 0.11 0.2 0.007 25.3 10.0 11.4 0.3 -- 0.02 -- .circleincircle. " 6 0.12 0.2 0.003 38.9 8.9 6.0 0.3 -- 0.18 -- .largecircle. " Comparative alloy 7 0.11 0.2 0.002 10.2 12.0 0.02 0.3 -- 0.23 -- X Austenite 8 0.12 0.3 0.003 14.8 11.4 0.31 0.3 -- 0.20 -- X " 9 0.10 0.2 0.008 26.8 11.3 0.3 0.3 -- 0.20 -- X " 10 0.09 0.2 0.010 39.8 10.8 0.4 0.3 -- 0.21 -- X " Alloy according to the present invention 11 0.12 0.2 0.009 12.0 10.8 6.0 0.3 0.2 0.20 -- .circleincircle. Ferrite & Austenite 12 0.13 0.5 0.01 12.2 9.9 5.1 0.3 -- 0.20 0.004 .circleincircle. " 13 0.09 0.4 0.03 11.2 10.1 5.3 0.3 -- 0.21 -- .circleincircle. " 14 0.20 0.2 0.02 10.8 9.8 7.2 0.3 0.4 0.03 0.005 .circleincircle. " Comparative alloy 15 0.19 0.5 0.01 10.4 9.0 0.01 0.3 0.1 0.22 0.003 X " 16 0.21 0.2 0.02 10.8 9.5 1.0 0.3 0.2 0.23 0.003 X " Alloy according to the present invention 17 0.20 0.01 0.010 5.8 10.01 2.0 0.3 -- 0.01 -- .largecircle. " 18 0.009 0.20 0.008 10.9 10.23 2.8 0.3 -- 0.01 -- .largecircle. Ferrite 19 0.10 0.10 0.009 21.0 9.98 2.9 0.2 0.2 0.01 -- .largecircle. Ferrite & Austenite 20 0.010 2.82 0.007 26.0 10.51 3.4 0.2 0.2 0.20 -- .largecircle. " __________________________________________________________________________ (.circleincircle.; raised due to irradiation, .largecircle.; concentratio was not lowered, X; concentration was lowered by 2% or more) EMBODIMENT 5 Table 4 shows, together with comparative alloys (Nos. 21 to 24), the alloys (Nos. 1 to 20 and Nos. 25 to 27) according to the present invention. Table 3 also shows the change in concentration of Cr at grain boundaries due to irradiation performed similarly to that performed in Embodiment 1. In the alloys Nos. 1 to 12 according to the present invention and prepared by substituting Mn and C or N by Ni, the lowering of concentration of Cr at grain boundaries due to the irradiation was prevented. In the alloys Nos. 13 to 20 according to the present invention and prepared by further adding one or more elements selected from a group consisting of Ti, Zr, Hf, Nb and Ta by a predetermined quantity, depletion of Cr concentration was prevented. As is shown, although a variety of elements are added, the effect of addition of aluminum according to the present invention can be obtained. The alloys Nos. 1 to 12, Nos. 14 to 20 and Nos. 26 and 27 have mixed structure of ferrite and austenite. The quantity of ferrite of each of the alloys Nos. 1 to 12 and Nos. 14 to 20 was 10 to 30% by area, while the alloys Nos. 26 and 27 contain ferrite by 50% by area. The alloys Nos. 13 and 25 are the alloys of complete ferritic structure, while the alloys Nos. 21 to 24 are alloys of complete austenitic structure. TABLE 4 __________________________________________________________________________ (wt %) Change in the concentration of Cr at Alloy No. C Si P Mn Ni Cr Mo Al N Ti Zr Hf Nb Ta grain boundaries __________________________________________________________________________ Alloy according to the present invention 1 0.07 0.5 0.02 25.0 3.0 11.0 2.2 5.0 0.01 .largecircle. 2 0.01 0.5 0.02 25.1 3.0 11.1 2.1 5.1 0.07 .largecircle. 3 0.05 0.5 0.02 25.4 3.0 10.8 2.3 5.1 0.02 .largecircle. 4 0.05 0.5 0.02 24.8 3.0 10.5 2.0 5.2 0.02 .largecircle. 5 0.07 0.5 0.02 5.0 13.9 17.1 2.0 5.8 0.01 .circleincircle. 6 0.01 0.5 0.02 5.1 13.7 17.4 2.1 5.0 0.07 .circleincircle. 7 0.05 0.5 0.02 5.0 13.9 17.3 2.2 5.9 0.02 .circleincircle. 8 0.05 0.5 0.02 5.2 13.8 17.0 2.1 5.8 0.02 .circleincircle. 9 0.06 0.5 0.01 10.1 9.8 13.5 2.0 5.0 0.01 .circleincircle. 10 0.01 0.5 0.02 10.2 9.8 13.2 2.1 5.3 0.07 .circleincircle. 11 0.05 0.5 0.02 10.1 9.9 13.1 2.2 5.9 0.01 .circleincircle. 12 0.05 0.5 0.02 10.3 9.7 13.1 2.2 5.8 0.02 .circleincircle. 13 0.01 0.5 0.02 25.5 3.0 10.4 2.0 5.0 0.01 0.3 .largecircle. 14 0.07 0.5 0.02 10.3 9.9 13.2 2.2 5.2 0.01 0.3 .circleincircle. 15 0.01 0.5 0.02 5.2 13.8 17.5 2.2 5.9 0.01 0.2 0.2 .circleincircle. 16 0.07 0.5 0.01 5.2 14.0 17.4 2.2 5.3 0.01 0.2 0.1 0.2 .circleincircle. 17 0.01 0.5 0.01 5.3 13.8 17.2 2.2 5.3 0.01 0.2 0.3 .circleincircle. 18 0.07 0.5 0.02 10.0 9.7 13.6 2.2 5.4 0.01 0.2 0.3 .circleincircle. 19 0.01 0.5 0.02 5.2 14.0 17.2 2.2 5.1 0.01 0.2 0.3 .circleincircle. 20 0.06 0.5 0.02 28.0 2.0 9.0 2.2 5.3 0.01 0.2 0.3 .largecircle. Comparative Alloy 21 0.01 0.5 0.02 25.2 3.0 10.9 2.2 0.01 0.02 X 22 0.05 0.5 0.02 10.0 9.7 13.4 2.2 1.8 0.01 X 23 0.02 0.5 0.02 25.0 3.1 10.5 2.2 0.01 0.03 0.2 0.2 X 24 0.05 0.5 0.02 10.0 9.2 13.7 2.2 1.0 0.01 0.2 0.1 0.3 X Present invention 25 0.01 0.5 0.01 25.1 3.0 10.8 2.2 2.0 0.01 .largecircle. 26 0.06 0.5 0.02 10.2 13.8 11.0 2.2 3.1 0.01 0.2 0.2 .largecircle. 27 0.03 0.5 0.01 5.3 9.8 11.3 2.3 2.3 0.01 0.2 0.1 .largecircle. __________________________________________________________________________ (.circleincircle.; concentration increased, .largecircle.; no lowering of concentration, X; concentration lowered by 2% or more) Then, an example of an apparatus in which the alloy according to the present invention is used will be described. FIG. 6 is a schematic perspective cut away view which illustrates a core portion of an essential portion of a boiling water type light-water nuclear reactor (BWR) nd FIG. 6A is an enlarged view of a portion of FIG. 6 showing a section of a channel box. Referring to the drawing, reference numeral 1 represents a neutron source pipe, 2 a core supporting plate, 3 a neutron instrumentation pipe, 4 a control rod, 5 a shroud and 6 an upper lattice plate. Those members and devices constitute the core of the light water nuclear reactor and are used in water in which a large quantity of neutrons are irradiated at high temperature of 288.degree. C. and high pressure of 7 MPa. Concentration of chromium at grain boundaries can be raised due to neutron irradiation by producing the members and devices with an Fe-Cr-Mn alloy according to the present invention. Therefore, corrosion resistance of those can be improved. In addition to the members and devices shown in FIG. 6, the alloy according to the present invention may be applied to component parts in vicinities of those members and devices. Also in this case, the similar effect can be obtained. Furthermore, the alloy according to the present invention may be applied to constituent members and devices of a core portion of a water cooling type nuclear reactor except for a boiling water type reactor. In this case, the similar effect can be obtained. In the case where the alloy according to the present invention stated in examples 1 to 4 is employed to make the neutron source pipe 1, the neutron instrumentation pipe 3, a control rod insertion pipe and the channel box 26 (see FIG. 6A) for a fuel assembly and a fuel cladding pipe 7, excellent stress corrosion cracking (SCC) resistance to neutron irradiation can be obtained. Those members can be obtained from an ingot of the alloy according to the present invention by a process of hot working and a repetition of cold working and annealing after solution treatment. The core supporting plate 2, the shroud 5, and the upper lattice plate 6 can be obtained from an ingot of the alloy according to the present invention by performing hot working and solution treatment. Furthermore, the core is constituted by the following devices or elements which may be made of the alloy according to the present invention; an upper mirror spray nozzle 8; a bent nozzle 9; a pressure vessel cover 10; a pressure vessel flange 11; a measuring nozzle 12; a steam separator 13; a shroud head 14; a supply water inlet nozzle 15; a jet pump 16; a recycling water outlet nozzle 17; a steam dryer 18; a steam outlet nozzle 19; a water supply supercharger 20; a core spraying nozzle 21; a lower core lattice 22; a recycling water inlet port nozzle 23; a baffle plate 24; and a control rod guide pipe 25. The alloy according to the present invention may be employed in an advanced inverter (ABWR) and a pressurized water reactor (PWR). The core of the ABWR comprise an internal pump as an alternative to the jet pump 16 of the above-described BWR. The other structure is arranged to be similar to that of BWR. Therefore, the alloy according to the present invention may be applied to the core elements and devices of the ABWR similarly to the elements and the devices for the BWR. As a result of the employment of the alloy according to the present invention, the safety can be improved significantly. FIG. 7 is a schematic cross sectional view which illustrates a TOKAMAK type nuclear fusion reactor and FIG. 7A is an enlarged view of a portion of FIG. 7 showing ceramic tiles 35. Referring to the drawing, reference numeral 31 represents a divertor, 32 a first wall and a cooling panel and 33 a vacuum vessel. Those members and devices constitute a core of a TOKAMAK nuclear fusion reactor. They are subjected to irradiation of a large quantity of neutrons and a variety of corpuscular beams allowed to leak from plasma and are brought into contact with cooling water, which is heated to high temperature by heat exchange, for the purpose of realizing the apparatus. When the above-described members and devices are made of the Fe-Cr-Mn alloy according to the present invention, lowering of the concentration of chromium at grain boundaries due to irradiation can be prevented. Therefore, corrosion resistance of those members can be improved. The above-described invertor 31, the first wall 32 and the vacuum vessel 33 are made of the alloy according to the present invention and have a structure arranged to be cooled with water. The divertor 31 and the first wall 32 comprise mechanically or metallurgically joined blocks or tiles 35 each of which is composed of elements of low atomic number (for example, SiC, Si.sub.3 N.sub.4, AlN, Al.sub.2 O.sub.3 and ceramics) on a surface of the metal member of the water cooling structure. The alloy according to the present invention may be also applied to those members and devices each of which is constituted by plates and pipes. Although omitted from illustration, a nuclear fusion reactor comprises a toroidal coil, a poloidal coil and a vacuum exhaust unit. An open magnetic field type reactor and an inertia containment laser heating type reactor are also known as nuclear fusion reactors. The alloy according to the present invention can also be applied to the above-described reactors, causing satisfactory reliability. As will be apparent from the above, lowering of concentration of chromium at grain boundaries due to irradiation of high-energy particles such as neutrons can be prevented by adding aluminum to an Fe-Cr-Mn alloy according to the present invention. Therefore, when the Fe-Cr-Mn alloy to which aluminum has been added is employed to manufacture members and devices for a core of a light-water nuclear reactor, a fast breeder, a nuclear fusion reactor or the like, deterioration in corrosion resistance and the strength of the alloy at grain boundaries can be prevented or the above-described characteristics can be improved. When the alloy according to the present invention is employed as material for constituting the core portion of a light-water nuclear reactor, irradiation assisted stress corrosion cracking (SCC) can be satisfactorily prevented. Although the invention has been described in its preferred form with a certain degree of particularly, it is understood that the present disclosure of the preferred form has been changed in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.
	abstract	It is an object of the invention to improve the quality of images obtained by an X-ray detector.
040385531	abstract	This disclosure pertains to a clamping apparatus having a stud capturing portion and a stud facing portion bolted together so as to compressively support a radiation proof sheet material, such as lead sheeting, there-in-between. The interior wall covering material, such as panelling or wall board is secured to the external surface of the stud facing portion. No nails are required to support the radiation-proof sheeting material, thereby minimizing accidental leakage due to harmful radiation passing through openings inadvertently disposed in the radiation-proof sheeting in the conventional nail securing supporting thereof. A pair of radiation-proof tracks capture the free ends of the stud capturing portion and the stud facing portion.
053373367	claims	1. A method of decreasing release of volatile radioactive iodine from a nuclear reactor pressure vessel containing a reactor core having a plurality of fuel rods submerged in reactor water, said method comprising the steps of: storing a stable iodide liquid solution in a reservoir operatively joined to said pressure vessel; monitoring said pressure vessel to determine an accident condition which might lead to rupture of said fuel rods resulting in the discharge into said reactor water of said volatile radioactive iodine from said fuel rods; and injecting into said pressure vessel upon occurrence of said accident condition said stable iodide liquid solution to mix with said reactor water for decreasing vaporization from said reactor water of said volatile radioactive iodine dischargeable therein from said fuel rods, wherein said stored iodide has a quantity selected relative to the quantity of said reactor water is said pressure vessel to effect a final concentration of total iodine from said stored iodide and reactor iodine contained in said reactor core of greater than about 10.sup.-5 Moles. storing a stable iodide liquid solution in a reservoir operatively joined to said pressure vessel, said stable iodide liquid solution comprising an iodide selected from the stable iodide group including sodium iodide (NaI) and potassium iodide (KI) and a stabilizer to inhibit oxidation of said stored iodide during storage; monitoring said pressure vessel to detect an accident condition which might lead to rupture of said fuel rods resulting in the discharge into said reactor water of said volatile radioactive iodine from said fuel rods; and injecting into said pressure vessel upon detection of said accident condition said stable iodide liquid solution to mix with said reactor water for decreasing vaporization from said reactor water of said volatile radioactive iodine dischargeable therein from said fuel rods, wherein said stored iodide has a quantity selected relative to the quantity of said reactor water in said pressure vessel to effect a final concentration of total iodine from said stored iodide and reactor iodine contained in said reactor core of greater than about 10.sup.-5 Moles. a pressure vessel; a reservoir containing a stored stable iodide in a liquid solution; a supply conduit joining said reservoir in flow communication with said pressure vessel; and a normally closed valve disposed in said supply conduit and being selectively openable for allowing said stored solution to flow into said pressure vessel to mix with said reactor water, wherein said stored iodide has a quantity selected relative to the quantity of said reactor water in said pressure vessel to effect a final concentration of total iodine from said iodide and reactor iodine contained in said reactor core of greater than about 10.sup.-5 Moles. 2. A method according to claim 1 wherein said iodide stored in said liquid solution in said reservoir is selected from the stable iodide group including sodium iodide (NaI) and potassium iodide (KI). 3. A method according to claim 2 wherein said stored liquid iodide solution further includes a stabilizer to inhibit oxidation of said stored iodide during storage in said reservoir. 4. A method according to claim 3, wherein said stored iodide is sodium iodide and said stabilizer is selected from the group including sodium hydroxide and sodium sulfite. 5. A method of decreasing release of volatile radioactive iodine from a nuclear reactor pressure vessel containing a reactor core having a plurality of fuel rods submerged in reactor water, said method comprising the steps of: 6. A nuclear reactor plant comprising: 7. An apparatus according to claim 6 wherein said stored iodide is selected from the stable iodide group including sodium iodide (NaI) and potassium iodide (KI). 8. An apparatus according to claim 7 wherein said stored solution in said reservoir includes a stabilizer to inhibit oxidation of said stored iodide during storage in said reservoir. 9. An apparatus according to claim 8 wherein said stored iodide is sodium iodide (NaI) and said stabilizer is selected from the group including sodium hydroxide (NaOH) and sodium sulfite (Na.sub.2 SO.sub.3).
	description	1. Technical Field The present invention disclosed herein relates generally to an apparatus and method for remotely, automatically loading drums filled with radioactive waste into a drum container, and more particularly to an apparatus and method for automatically loading drums into a drum container, in which when the drums filled with the radioactive waste are loaded into the drum container, the drums are fed to a designated position, and always placed at a fixed position, thereby reducing a loading time of the drums and necessary manpower as well as minimizing a radiation exposure risk associated with radioactive waste treatment. 2. Related Art In general, radioactive waste is inevitably generated from systems or facilities using atomic energy such as atomic power stations. This radioactive waste must be carefully treated due to radiation of radioactive rays that are harmful to the human body. As such, it is important to treat the radioactive waste within as short a time as possible, and workers must handle the radioactive waste from as far away as possible so as not to be directly exposed to the radioactive waste. Conventionally, in order to load the drum filled with the radioactive waste into the drum container, the drum container is placed at a given place, and then a lid of the drum container is opened using a lid handling unit or a crane hook. The drums placed at another given place are loaded into the drum container using a drum gripper, and then the drum container lid is gripped and covered on the drum container. In this case, an operator of the drum loading apparatus must check a position of the drum using a monitoring camera or with his or her eye, and manipulate the drum gripper to grip the drum. Therefore the drum gripper may collide with the drum or it may be difficult to correctly grip the drum. Even after the drum is gripped by the drum gripper, the operator must operate the drum gripper while watching an upper portion and sides of the drum container in order to avoid collision with the drum loaded in the drum container in the process of loading the drum to a designated position of the drum container, and thus it takes much time to load the drum. In addition, in the process of covering the drum container lid on a body of the drum container again after the drums are loaded, the operator approaches the drum container in which the radioactive waste drums are contained, checks whether or not holes of bolts for coupling the drum container are matched with his or her eye, and adjusts a position of the drum container lid so as to be fitted to the bolt holes. Therefore, much manpower and working time are required, resulting in a radiation exposure risk. The present invention is directed to an apparatus and method for automatically loading drums into a drum container, in which when the drum filled with radioactive waste is loaded into the drum container, the drum is fed to a designated position so as to be easily gripped by a gripper, and always located at a fixed place, thereby enabling automation of a drum loading process. According to an aspect of the present invention, there is provided an apparatus for automatically loading drums into a drum container, which includes: a drum feeder having: a plurality of conveyor modules transferring the drums filled with radioactive waste; and a turntable rotating the drum transferred by the conveyor modules in a direction where the drum can be gripped by a gripper; a drum container into which the drums transferred through the drum feeder are sequentially loaded; a support frame on which a lid of the drum container is placed when the drums are loaded; and a crane having: the gripper that grips and transfers the drum or the drum container lid; and a lifter on which the gripper is mounted so as to move up and down and which is transferred along guide rails in forward and backward, or left and right directions. In exemplary embodiments, the drum feeder may further include: sensors sensing a position of a drum bolt fastened on an outer circumference of the drum; and a controller controlling a rotational amount of the turntable on a basis of position signals of the drum bolt sensed by the sensors. In exemplary embodiments, each conveyor module may include an interlocking unit that restricts movement of the downstream conveyor module when the drum is located on the upstream conveyor module. In exemplary embodiments, the gripper may include: a plurality of gripper arms radially installed at regular angular intervals; an arm hydraulic unit reciprocating the gripper arms in a radial direction; jaws installed on inner sides of the gripper arms and gripping an outer surface of the drum by operation of the arm hydraulic unit; and latches protruding from the inner sides of the gripper arms and latched on the drum container lid. In exemplary embodiments, the lifter may include a plurality of cylinders and rods for transferring the gripper in upward and downward directions so as to prevent the gripper gripping the drum or the drum container lid from swinging. According to another aspect of the present invention, there is provided an apparatus for automatically loading drums into a drum container, which include: a drum feeder transferring the drums filled with radioactive waste; a drum container into which the drums transferred through the drum feeder are sequentially loaded; a support frame on which a lid of the drum container is placed when the drums are loaded; a crane having: the gripper that grips and transfers the drum or the drum container lid; and a lifter on which the gripper is mounted so as to move up and down and which is transferred along guide rails in forward and backward, or left and right directions; and a drum container clamp having: drum container pedestals on which corners of the bottom of the drum container are supported; and a pusher that pushes the drum container supported on the drum container pedestals on one side of the drum container and fixes the drum container in close contact with the drum container pedestals on the other side of the drum container. In exemplary embodiments, each drum container pedestal may include: a base plate; and a bracket whose shape corresponds to a shape of each corner of the bottom of the drum container and which protrudes upward from the base plate. In exemplary embodiments, the brackets may be disposed at a slightly longer distance than a length of the drum container in a direction where the drum container is pushed by the pusher, and at a distance corresponding to a width of the drum container in a direction perpendicular to the direction where the drum container is pushed by the pusher. In exemplary embodiments, the pusher may include a hydraulic cylinder and an oil supply. In exemplary embodiments, the gripper may include: a plurality of gripper arms radially installed at regular angular intervals; an arm hydraulic unit reciprocating the gripper arms in a radial direction; jaws installed on inner sides of the gripper arms and gripping an outer surface of the drum by operation of the arm hydraulic unit; and latches protruding from the inner sides of the gripper arms and latched on the drum container lid. In exemplary embodiments, the lifter may include a plurality of cylinders and rods for transferring the gripper in upward and downward directions so as to prevent the gripper gripping the drum or the drum container lid from swinging. According to yet another aspect of the present invention, there is provided a method of automatically loading drums into a drum container, which includes: placing the drum container on pedestals for the drum container into which the drums filled with radioactive waste are loaded; pushing one side of the drum container placed on the drum container pedestals on one side of the drum container using a pusher and fixing the drum container in close contact with the drum container pedestals located on the other side of the drum container; separating a lid of the drum container from a body of the drum container using a gripper; transferring the drums to a turntable using a plurality of conveyor modules; rotating the turntable to position the drum placed on the turntable so as to be directed to a direction where the drum can be gripped by the gripper; sequentially loading the drums into the drum container using the gripper; and placing the drum container lid on the drum container body using the gripper when the loading of the drums is completed. In exemplary embodiments, rotating the turntable to position the drum placed on the turntable so as to be directed to a direction where the drum can be gripped by the gripper may include: sensing, by sensors, a position of a drum bolt fastened on an outer circumference of the drum; and controlling a rotational amount of the turntable on a basis of position signals of the drum bolt sensed by the sensors. A further understanding of the nature and advantages of the present invention herein may be realized by reference to the remaining portions of the specification and the attached drawings. Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art Like reference numerals refer to like elements throughout the accompanying figures. FIGS. 1A and 1B are a plan view and a front view of an apparatus for automatically loading drums into a drum container according to an exemplary embodiment of the present invention. An apparatus for automatically loading drums and a drum container according to an exemplary embodiment of the present invention includes a drum feeder 10 transferring a drum 5 filled with radioactive waste toward a crane 50, a drum container 20 having a body 21 and a lid 22 into which a plurality of drums 5 are loaded, a drum container clamp 30 fixing the drum container 20 within the drum loading apparatus, and a support frame 40 on which the drum container lid 22 separated from the drum container body 21 is placed when the drums 5 are loaded. The crane 50 is equipped with a lifter 55 moving along guide rails 52 in forward and backward, or left and right directions, and a gripper 60 selectively gripping the drum 5 or the drum container lid 22 at a lower end of the lifter 55 and moving in cooperation with the lifter 55. The lifter 55 is provided with a plurality of cylinders 55a and rods 55b, and is coupled to an upper portion of the gripper 60. Thus, when the drum 5 is loaded, the gripper 60 gripping the drum 5 is prevented from swinging when moving in forward and backward, or left and right directions, so that it can load the drum 5 at an exact position in the drum container 20. FIGS. 2A through 2C illustrate construction of a drum feeder in an apparatus for automatically loading drums into a drum container according to an exemplary embodiment of the present invention, in which FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a front view illustrating the state where no drum is located on a turntable. The drum feeder 10 includes a plurality of conveyor modules 12 sequentially transferring the drums 5, and a turntable 15 rotating the drum 5 transferred by the conveyor modules 12 in a direction where the drum 5 can be gripped by the gripper 60. Each conveyor module 12 may include a plurality of rollers 12a, a belt 12b moving along the rollers, and a conveyor driving motor 12c rotating the rollers. The turntable 15 is installed adjacent to the rear of the most downstream conveyor module of the conveyor modules 12. Each conveyor module 12 is provided with sensors 14 on opposite long sides thereof which sense the position of the drum 5. The turntable 15 is provided with sensors 16 (16a and 16b) which sense the position of a drum bolt 5a fastened on an outer circumference of an upper end of the drum 5 (see FIGS. 2C and 4). Further, the drum feeder 10 includes a controller (not shown), which controls an operation of each conveyor module 12 and a rotational amount of the turntable 15 on the basis of the signals sensed by the sensors 14 and 16. The sensors 14, which are installed on the opposite long sides of the conveyor module 12, sense the position of the drum 5 within each conveyor module 12, and send signals obtained by sensing the position of the drum 5 to the controller. When the drum 5 is located on the upstream conveyor module, the controller drives an interlocking unit (not shown) so as to restrict the operation of the downstream conveyor module. In this way, the drum feeder 10 controls the operation of the conveyor modules 12 using the sensors 14, the controller, and the interlocking unit, so that it is possible to previously prevent the drums 5 from being damaged by collision between the drums 5 located upstream and downstream of the conveyor modules in the process of feeding the drums 5. The sensors 16a and 16b installed on the turntable 15 sense the position of the drum bolt 5a fastened on the outer circumference of the drum 5 placed on the turntable 15, and send signals obtained by sensing the position of the drum bolt 5a to the controller. The controller controls the rotational amount of the turntable 15 such that a position where the gripper 60 grips the drum 5 in close contact with the outer surface of the drum 5 is located at a portion where the drum bolt 5a is not fastened. Here, as illustrated in FIG. 2C, the sensors 16a and 16b may be configured to be located at different heights considering that the drums 5 have different heights depending on their capacities (e.g. 200 liters, 320 liters). FIGS. 3A and 3B illustrate construction of a drum container clamp in an apparatus for automatically loading drums into a drum container according to an exemplary embodiment of the present invention, in which FIG. 3A is a plan view, and FIG. 3B is a front view. The drum container clamp 30 includes drum container pedestals 33 on which corners of the bottom of the drum container 20 are supported, and a pusher that pushes the drum container 20 supported on the drum container pedestals 33 on one side of the drum container 20 and thus fixes the drum container 20 in close contact with the drum container pedestals 33-1 on the other side of the drum container 20. In this embodiment, the drum container 20 has the shape of a hollow cuboid, and includes a body 21 in which the drums 5 are loaded and a lid 22 covering the top of the body 21. For the structure of the drum container 20 having this cuboidal shape, each drum container pedestal 33 includes a base plate 33a fixedly installed on the floor of a building and supporting each corner of the bottom of the drum container 20, and an L-shaped bracket 33b protruding upward from the base plate 33a. As illustrated in FIG. 3A, the brackets 33b are disposed at a slightly longer distance than a length of the drum container 20 in a direction where the drum container 20 is pushed by the pusher, and at a distance corresponding to a width of the drum container 20 in a direction perpendicular to the direction where the drum container 20 is pushed by the pusher. The pusher may be made up of a hydraulic cylinder 31 and an oil supply 32. Thus, when the drum container 20 is placed inside the brackets 33b of the drum container pedestals 33, the hydraulic cylinder 31 is driven by an oil pressure supplied from the oil supply 32, and thus presses and pushes one side of the drum container 20. Thereby, the other side of the drum container 20 is closely fixed to inner surfaces of the brackets 33b of the drum container pedestals 33-1 located on the other side of the drum container 20. FIG. 4 illustrates construction of a gripper for gripping a drum and a drum container lid in an apparatus for automatically loading drums into a drum container according to an exemplary embodiment of the present invention. The gripper 60 is characterized by a structure in which the drum 5 and the drum container lid 22 can be compatibly transferred when the drum 5 is loaded into the drum container 20 from the drum feeder 10. In FIG. 4, the state where the gripper 60 grips the drum 5 is shown. The gripper 60 includes a plurality of gripper arms 61 radially installed at regular angular intervals, an arm hydraulic unit 62 reciprocating the gripper arms 61 in a radial direction, jaws 63 installed on inner sides of the gripper arms 61 and gripping an outer surface of the drum 5, and latches 64 protruding from the inner sides of the gripper arms 61 and latched on the drum container lid 22. The gripper 60 may further include an arm rotating mechanism 65, which rotates the gripper arms 61 to a position where it is easy to grip the drum 5. The jaws 63 may be installed on inner sides of lower portions of the gripper arms 61 in consideration of the gripping position of the drum 5. The latches 64 may be installed on inner sides of lower ends of the gripper arms 61 in consideration of a latching position of the drum container lid 22. Now, a method of loading the drums 5 into the drum container 20 using the drum feeder 10 and the drum container clamp 30 will be described step by step. To load the drums 5, which are transferred by the drum feeder 10, into the drum container 20, the drum container 20 must be fixed using the drum container clamp 30, and the lid 22 of the drum container 20 must be separated from the body 21 of the drum container 20, and then be transferred to the support frame 40. First, when the drum container 20 is placed on the drum container pedestals 33, the oil supply 32 of the drum container clamp 30 applies an oil pressure to the hydraulic cylinder 31, and thus the hydraulic cylinder 31 is operated to push the drum container 20 toward the drum container pedestals 33-1 located on the side opposite the hydraulic cylinder 31. When the drum container 20 is pushed toward and closely contacted with the brackets 33b of the drum container pedestals 33-1 on the side opposite the hydraulic cylinder 31 by the operation of the hydraulic cylinder 31, bolts connecting the body 21 and lid 22 of the drum container 20 are unfastened, and then the drum container lid 22 is gripped by the gripper 60, and is transferred to the support frame 40. Then, the drum 5 is transferred to the turntable 15 through the drum feeder 10, and then the drums 5, each of which is placed on the turntable 15, are sequentially loaded into the drum container 20 using the gripper 60. When the drum 5 is transferred to the turntable 15 through the conveyor modules 12 of the drum feeder 10, and then the turntable 15 on which the drum 5 is placed is rotated such that the drum 5 placed on the turntable 15 is directed to a direction where the gripper 60 can grip the drum 5. Here, the controller controls a rotational amount of the turntable 15 on the basis of a position signal of the drum bolt 5a sensed by the sensors 16 such that the drum bolt 5a is located at a position where it does not interfere with the gripper arms 61 of the gripper 60 when the drum 5 is gripped by the gripper 60. When the drum 5 placed on the turntable 15 is located at a designated position, the gripper 60 grips the drum 5, and the lifter 55 raises the gripper 60 gripping the drum 5, and moves in forward and backward, or left and right directions by the crane 50, and lowers the gripper 60 above a designated position within the drum container 20. Thereby, the drum 5 is automatically loaded. When this process is repeated, and thus the drums 5 are completely loaded into the drum container 20, the gripper 60 moves to the support frame 40, grips the drum container lid 22, transfers the drum container lid 22 above the drum container body 21, and lowers the drum container lid 22. In this case, when a position control system is applied, the drum container lid 22 is placed on the drum container body 21 in the same state when it is separated from the drum container body 21. According to an exemplary embodiment of the present invention, the drum loading apparatus is configured to employ the drum feeder and the drum container clamp, and to connect the lifter with the gripper via the cylinders and the rods such that the drum is prevented from swinging while being transferred, so that the process of loading the drums can be automated to enhance accuracy of the loading position. Further, the collisions between the drum and the drum container and between the drums are prevented when the drums are loaded, so that it is possible to prevent damage of the drum, maximize the efficiency of operation when a large quantity of drums are loaded, enhance safety when a heavy object is handled, and reduce necessary manpower and time. In addition, since the lid is covered on the drum container after the drums are completely loaded, no separate process or apparatus for positioning a position of the lid is required, so that it is possible to minimize the radiation exposure risk of a worker.
	claims	1. A waste capsule, wherein the waste capsule is configured for:(a) receiving and housing a predetermined quantity of waste;(b) being finally disposed of within a distal portion of a wellbore or in a human-made cavern, wherein the distal portion or the human-made cavern is located within a deep geological formation that is at least five thousand feet below the Earth's surface; and(c) falling within both a wellbore viscous fluid and the wellbore, wherein the wellbore includes the wellbore viscous fluid;wherein the waste capsule is a substantially elongate cylindrical member, comprising a conical nose, a capsule body, and a tail end; wherein the conical nose is connected to the capsule body, the capsule body is also connected to the tail end, such that the capsule body is disposed of between the conical nose and the tail end, wherein the capsule body is substantially hollow and is configured to receive and house the predetermined quantity of waste;wherein the conical nose is conical in shape terminating at a tip that is pointed or wherein the conical nose is dome shaped, wherein the tip is furthest away from the tail end and wherein the tip is colinear with a longitudinal axis of the waste capsule;wherein the tail end comprises at least one stabilizer that extends orthogonally away from an exterior side wall of the capsule body and that extends beyond an outer diameter of the capsule body, wherein the at least one stabilizer is configured to minimize instability of the waste capsule when the waste capsules falls within the wellbore viscous fluid and falls within the wellbore;wherein the conical nose comprises a first connector; wherein the first connector is configured to attach to a connector of a tail end of a different waste capsule. 2. The waste capsule according to claim 1, wherein an exterior shape of the waste capsule is substantially smooth and streamlined to minimize friction against the wellbore viscous fluid. 3. The waste capsule according to claim 1, wherein the tail end comprises a second connector; wherein the second connector is configured to attach to a connector of a conical nose of another waste capsule. 4. The waste capsule according to claim 1, wherein the at least one stabilizer is one or more of: internal fins, external fins, or drag vanes. 5. The waste capsule according to claim 1, wherein the capsule body comprises at least one centralizer, wherein the at least one centralizer is configured to keep the waste capsule substantially within a center of the wellbore when the waste capsule is falling within the wellbore. 6. The waste capsule according to claim 1, wherein the conical nose comprises at least one crash attenuator, wherein the at least one crash attenuator is configured to absorb at least some energy from an impact on the waste capsule such that a rupture of the capsule body is minimized. 7. A waste capsule, wherein the waste capsule is configured for:(a) receiving and housing a predetermined quantity of waste;(b) being finally disposed of within a distal portion of a wellbore or in a human-made cavern, wherein the distal portion or the human-made cavern is located within a deep geological formation that is at least five thousand feet below the Earth's surface; and(c) falling within both a wellbore viscous fluid and the wellbore, wherein the wellbore includes the wellbore viscous fluid;wherein the waste capsule is a substantially elongate cylindrical member, comprising a conical nose, a capsule body, and a tail end; wherein the conical nose is connected to the capsule body, the capsule body is also connected to the tail end, such that the capsule body is disposed of between the conical nose and the tail end, wherein the capsule body is substantially hollow and is configured to receive and house the predetermined quantity of waste;wherein the conical nose is conical in shape terminating at a tip that is pointed or wherein the conical nose is dome shaped, wherein the tip is furthest away from the tail end and wherein the tip is colinear with a longitudinal axis of the waste capsule;wherein the tail end comprises at least one stabilizer that extends orthogonally away from an exterior side wall of the capsule body and that extends beyond an outer diameter of the capsule body, wherein the at least one stabilizer is configured to minimize instability of the waste capsule when the waste capsules falls within the wellbore viscous fluid and falls within the wellbore;wherein the tail end comprises a first connector; wherein the first connector is configured to attach to a second connector of a conical nose of a different waste capsule. 8. A waste capsule, wherein the waste capsule is configured for:(a) receiving and housing a predetermined quantity of waste;(b) being finally disposed of within a distal portion of a wellbore or in a human-made cavern, wherein the distal portion or the human-made cavern is located within a deep geological formation that is at least five thousand feet below the Earth's surface; and(c) falling within both a wellbore viscous fluid and the wellbore, wherein the wellbore includes the wellbore viscous fluid;wherein the waste capsule is a substantially elongate cylindrical member, comprising a conical nose, a capsule body, and a tail end; wherein the conical nose is connected to the capsule body, the capsule body is also connected to the tail end, such that the capsule body is disposed of between the conical nose and the tail end, wherein the capsule body is substantially hollow and is configured to receive and house the predetermined quantity of waste;wherein the conical nose is conical in shape terminating at a tip that is pointed or wherein the conical nose is dome shaped, wherein the tip is furthest away from the tail end and wherein the tip is colinear with a longitudinal axis of the waste capsule;wherein the conical nose comprises at least one crash attenuator, wherein the at least one crash attenuator is configured to absorb at least some energy from an impact on the waste capsule such that a rupture of the capsule body is minimized;wherein the tail end comprises at least one stabilizer that extends orthogonally away from an exterior side wall of the capsule body and that extends beyond an outer diameter of the capsule body, wherein the at least one stabilizer is configured to minimize instability of the waste capsule when the waste capsules falls within the wellbore viscous fluid and falls within the wellbore.
	claims	1. An X-ray fluorescence analysis apparatus comprising: an X-ray generator; an X-ray detector; a housing; and a collimator for defining a range for the passage of X-rays from the X-ray generator; wherein a right-hand screw thread is provided on a first side of the collimator for attachment of the collimator to the housing and detachment of the collimator from the housing, a corresponding right-hand screw thread is provided in the housing for receiving the right-hand screw thread provided on the collimator, and a left-hand screw thread is provided on a second side of the collimator opposite the first side coaxial with the right-hand screw thread for attachment of the collimator to an attachment jig for attachment of the collimator to the housing and detachment of the collimator from the housing. 2. An X-ray fluorescence analysis apparatus according to claim 1 ; wherein the collimator is provided with an indentation or projection for tightening. claim 1 3. An X-ray fluorescence analysis apparatus according to claim 1 ; wherein the right-hand screw thread of the collimator is an external screw thread and the right-hand screw thread of the housing is an internal screw thread. claim 1 4. An X-ray fluorescence analysis apparatus according to claim 1 ; wherein the right-hand screw thread of the collimator is an internal screw thread and the right-hand screw thread of the housing is an external screw thread. claim 1 5. An X-ray fluorescence analysis apparatus according to claim 1 ; wherein the attachment jig has a left-hand screw thread for receiving the left-hand screw thread of the collimator for screwing the collimator into the right-hand screw thread of the housing and unscrewing the collimator from the right-hand screw thread of the housing. claim 1 6. An X-ray fluorescence analysis apparatus comprising: an X-ray generator; an X-ray detector; a housing; and a collimator for defining a range for the passage of X-rays from the X-ray generator; wherein a right-hand screw thread is provided on a first side of the collimator for attachment of the collimator to the X-ray generator and detachment of the collimator from the X-ray generator, a corresponding right-hand screw thread is provided in the X-ray generator for receiving the right-hand screw thread provided on the collimator, and a left-hand screw thread is provided on a second side of the collimator opposite the first side coaxial with the right-hand screw thread for attachment of the collimator to an attachment jig for attachment of the collimator to the X-ray generator and detachment of the collimator from the X-ray generator. 7. An X-ray fluorescence analysis apparatus according to claim 6 ; wherein the collimator is provided with an indentation or projection for tightening. claim 6 8. An X-ray fluorescence analysis apparatus according to claim 6 ; wherein the right-hand screw thread of the collimator is an external screw thread and the right-hand screw thread of the X-ray generator is an internal screw thread. claim 6 9. An X-ray fluorescence analysis apparatus according to claim 6 ; wherein the right-hand screw thread of the collimator is an internal screw thread and the right-hand screw thread of the X-ray generator is an external screw thread. claim 6 10. An X-ray fluorescence analysis apparatus according to claim 6 ; wherein the attachment jig has a left-hand screw thread for receiving the left-hand screw thread of the collimator for screwing the collimator into the right-hand screw thread of the X-ray generator and unscrewing the collimator from the screw thread of the X-ray generator. claim 6 11. An X-ray fluorescence analysis apparatus comprising: an X-ray generator; an X-ray detector; a housing; and a collimator for defining a range for the passage of X-rays from the X-ray generator; wherein a right-hand screw thread is provided on a first side of the collimator for attachment of the collimator to the X-ray detector and detachment of the collimator from the X-ray detector, a corresponding right-hand screw thread is provided in the X-ray detector for receiving the right-hand screw thread provided on the collimator, and a left-hand screw thread is provided on a second side of the collimator opposite the first side coaxial with the right-hand screw thread for attachment of the collimator to an attachment jig for attachment of the collimator to the X-ray detector and detachment of the collimator from the X-ray detector. 12. An X-ray fluorescence analysis apparatus according to claim 11 ; wherein the collimator is provided with an indentation or projection for tightening. claim 11 13. An X-ray fluorescence analysis apparatus according to claim 11 ; wherein the right-hand screw thread of the collimator is an external screw thread and the right-hand screw thread of the X-ray detector is an internal screw thread. claim 11 14. An X-ray fluorescence analysis apparatus according to claim 11 ; wherein the right-hand screw thread of the collimator is an internal screw thread and the right-hand screw thread of the X-ray detector is an external screw thread. claim 11 15. An X-ray fluorescence analysis apparatus according to claim 11 ; wherein the attachment jig has a left-hand screw thread for receiving the left-hand screw thread of the collimator for screwing the collimator into the right-hand screw thread of the X-ray detector and unscrewing the collimator from the screw thread of the X-ray detector. claim 11 16. An X-ray apparatus comprising: an X-ray generator for generating X-rays; an X-ray detector for detecting X-rays; a housing attached to at least one of the X-ray generator and the X-ray detector; a collimator for collimating X-rays generated by the X-ray generator; and a first screw thread formed on one of the X-ray generator, the X-ray detector and the housing for receiving the collimator; wherein the collimator has a second screw thread on a first side for mounting the collimator to the first screw thread and a third screw thread on a second side having a threading direction opposite from that of the second screw thread for attachment to a mounting jig. 17. An X-ray apparatus according to claim 16 ; wherein the first screw thread is a right-hand screw thread, the second screw thread of the collimator is a right-hand screw thread, and the third screw thread of the collimator is a left-hand screw thread. claim 16 18. An X-ray apparatus according to claim 17 ; wherein the right-hand screw thread of the collimator is an external screw thread and the first screw thread is an internal screw thread. claim 17 19. An X-ray apparatus according to claim 17 ; wherein the right-hand screw thread of the collimator is an internal screw thread and the first screw thread is an external screw thread. claim 17 20. An X-ray apparatus according to claim 16 ; wherein the collimator has one of an indentation or a projection for tightening, and the mounting jig has the other one of an indentation or a projection corresponding to the indentation or projection of the collimator. claim 16
051685132	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to x-ray lithography and metrology systems, and more particularly to alignment or detection systems for that purpose. 2. Description of related art. In lithography, it is known to employ visible light to perform measurements in alignment systems. However, when measurements are to be made in x-ray technology, the limits of conventional optical measurements are exceeded. These limits are in general, caused by the fact that systems using visible optics are less accurate than is required because of wavelength limitations. U.S. Pat. No. 4,016,416 of Shepherd et al, for "Phase Compensated Zone Plate Photodector" shows a zone plate with a photodetector mounted on the opposite face. U.S. Pat. No. 3,984,680 of Smith for "Soft X-Ray Mask Alignment System" shows an x-ray mask alignment system with x-ray fluorescence detectors mounted on the mask which measure the x-ray fluorescent signal which provides a low intensity output as compared with an electron flux. U.S. Pat. No. 4,614,433 of Feldman for "Mask-to-Wafer Alignment Utilizing Zone Plates" shows mask to wafer alignment using zone plates illuminated by light during alignment. In accordance with this invention, a method and apparatus is provided for aligning an x-ray lithography system including an x-ray mask and a work piece with an alignment mark, including the steps as follows: a) including means on the x-ray mask for focussing the x-ray beam on the work piece such as a zone plate or grating, b) directing x-rays through the means for focussing at the alignment mark for detecting when the lens or grating is aligned with the mark by emission of photoelectrons generated by the work piece in response to the x-rays and detecting the change of current when the x-ray beam crosses a feature on the alignment mark. Preferably the alignment mark comprises an etched slot or a metal feature. Further in accordance with this invention, an apparatus and a method are provided to improve the detection capabilities of a metrology system for measuring a work piece in connection with a plurality of fiducial marks forming an array on the work piece, comprising a) providing an x-ray source, b) providing a means for focussing such as a zone plate lens or a grating on an x-ray transparent substrate, c) directing x-rays through the zone plate lens to a first one of the fiducial marks for detecting when the lens or grating is aligned with the mark by emission of photoelectrons generated by the work piece in response to the x-rays and detecting the change of current when the x-ray beam crosses a feature on the first one of the fiducial marks, d) a laser interferometrically controlled table that determines the position between two of the fiducial marks in the array of marks. previously defined on the work piece.
062529226	description	DESCRIPTION OF THE INVENTION Hereinafter, as one embodiment of a method of handling a nuclear reactor and an apparatus used in the handling method according to the present invention, an atomic power plant station having a boil water type nuclear reactor will be explained by taking as an exemplified example. However, the present invention will be applied to an atomic power plant station having another type of nuclear reactor. In a nuclear reactor building 11 of an atomic power plant station having a boil water type nuclear reactor shown in FIG. 1, a nuclear reactor pressure vessel 3 is provided and this nuclear reactor pressure vessel 3 is stored by a nuclear reactor storing vessel 21. In the nuclear reactor pressure vessel 3, as shown in FIG. 2, as an internal structure a steam dryer 5 and a vapor-liquid separator 8 and a shroud 1 etc. are provided. In a space of an operation floor 9 of the nuclear reactor building or containment 11, an overhead crane 8 is provided, and the overhead crane 8 is used in the working of the operation floor 9. In the operation floor 9, a dryer separator pool 7 which is abbreviated as "DS pool" and a nuclear reactor well pool 10 which communicates to an interior portion of the nuclear reactor pressure vessel 3 are provided. Among the internal structures, since the shroud 1 is a component which surrounds a reactor core of the nuclear reactor, among the internal structures the shroud 1 most strongly receives the radiation. In this embodiment according to the present invention, the working for exchanging over the shroud 1 will be explained. The nuclear reactor pressure vessel 3 in the nuclear reactor building 11 of the atomic power plant station receives the fuels of the nuclear reactor and is a vessel to which a primary cooling member comprised the liquid is inserted. The reactor core to which the fuels of the nuclear reactor are mounted is surrounded by the shroud 1, and this shroud 1 is formed with a stainless steel cylindrical structure which isolates a flow in the cooling member which raises in the nuclear reactor and a re-circulation flow which descends a ring shape portion between an inner wall of the nuclear reactor pressure vessel 3. In this embodiment according to the present invention, the shroud 1 which is a subject of a carry-in working and a carry-out working between the inside and the outside of the nuclear reactor building 11 is a main large weight product among the machines and the apparatuses for constituting the atomic power plant station and has 70 tons weight. The internal structure receives the high concentration radioactive rays because the internal structure is a machinery product which is passed through a primary system coolant and this internal structure is covered by a reinforce concrete shielding wall or a steel plate concrete shielding wall. Further, a surrounding of the internal structure is stored in a steel shape nuclear reactor storing container 21 and this internal structure works a role of the prevention of the leakage of the radiation. These atomic power plant stations, during a periodic inspection a damage state of the internal structure of the nuclear reactor is inspected, according to the demand, the internal structure is mended, however from the aspects of the economical performance and the prevention preservation, even in a midway of the durable years, there is a case over which the internal structure is exchanged. To carry out the exchange-over for the internal structure, first of all to a sealing roof of the nuclear reactor building 11 which is positioned at a just above of the well pool 10 an opening 61 is formed as shown in FIG. 12. The opening portion 61 is closed once according to a curing sheet 63 or a rolling system shutter 62. In a case where an outside shielding wall 31 is installed at a roof portion of the nuclear reactor building 11, the carry-in and carry-out use opening 61 is provided at the outside shielding wall 31 and this opening 61 has a size in which a cask 41 is enable to pass through. At the same time, a large scale lifting machine 91 which is a large scale crawler crane is installed at a vicinity of the nuclear reactor building 11. In a case of the installation of the large scale lifting machine 91, as shown in FIG. 12, the ground for an operation area of the large scale lifting machine 91 is strengthened as an establishment ground 71. Further, as shown in FIG. 12, at the ground within a loading working radius range of the large scale lifting machine 91, an underground reservoir 81 is formed and an inlet port of this underground reservoir 81 is opened upwardly. Next, the carry-out working of the shroud 1 to the nuclear reactor building is carried out and in this carry-out working the cask 41 is used. The cask 41 is pulled up and supported by a wire rope 12 from the lifting balance 51, as shown in FIG. 5. The cask 41 is constituted by a lower portion opened container having an inlet port at a lower portion. And at the ceiling portion of this cask 41, a penetrating hole 54 is provided and in this penetrating hole 54 a wire rope 13 of a hoisting device 52 is passed through. This hoisting device 52 is installed to the lifting balance 51 and then the wire rope 13 is wounded up or paid out according to a remote operation. A hook 14 is provided to this wire rope 13. The lifting balance 51 and a hook block 93 of the large scale lifting machine 91 are connected by a wire rope 28 and the lifting balance 51 is pulled up and supported by the large scale lifting machine 91 to lift up and lift down freely. The combination equipment of the above stated lifting balance 51, the hoisting device 52, and the cask 41 is prepared at the outer side of the nuclear reactor building 11. As shown in FIG. 6(a) and FIG. 6(b), to close the inlet port 27 provided at a bottom portion of the cask 41, at an outer periphery of a cask bottom plate 42, mail screws 42a of the cask bottom plate 42 is provided to engage with female screws 42b which are processed at an inner wall face of the lower portion of the cask 41. The cask bottom plate 42 is mounted to the bougie car 43 through a receiving table 46. The bougie car 43 is stridden over the well pool 10 and DS pool 7 and is installed to run freely on a rail 15 which is laid along to the well pool 10 and DS pool 7. The construction of the receiving table 46 is as following. Namely, as shown in FIG. 14, the receiving table is constituted by a rotary table 17 which is mounted on the bougie car 43 to rotate freely toward a horizontal direction through a thrust bearing 16, an ascend and descend table 19 which is mounted on the rotary table 17 through an air pressure cylinder apparatus 18, an inner gear 20 which is fixed to the above stated rotary table 17, and a motor 23 for rotating and driving a pinion 22. The manner for extending and contracting a piston rod of the air pressure cylinder apparatus 18 and the drive control of the motor 23 can be carried out from a remote place. Accordingly, when the pinion 22 is rotated and driven by the motor 23, the inner gear 20 and the rotary table 17 are rotated at the same time at a horizontal face. Further, by extending and contracting the piston rod of the air pressure cylinder apparatus 18 the ascend and descend table 19 can be moved toward the upward and downward direction, and then the ascend and descend table 19 can give the rotation operation and the ascending and descending operation to the cask bottom plate 42. In place of the respective screws 42a and 42b of the cask 41 to the cask bottom plate 42, as shown in FIG. 7(a) and FIG. 7(b), faucet structures 44a and 44b can be employed. Further, as shown in FIG. 8(a) and FIG. 8(b), a bolt 24 is passed through a flange 45b which is fixed to the cask 41, and a structure can be employed in which the cask bottom plate 42 is fastened to the cask according to the bolt 24 which is passed through a bolt passing-through hole 45a and a nut 25. As stated in above, the preparation of the exchange over working is carried out, the exchange-over working is carried out as following. FIG. 3 and FIG. 4 show an outline exchange-over working procedure in which the shroud 1 being the internal structure of the nuclear reactor is an object for exchanging over. To exchange over of the shroud 1, firstly a working for taking out the already established shroud 1 in the nuclear reactor pressure vessel 3 precedes. As the taking-out procedure, a cover 4 of the nuclear reactor pressure vessel 3 is released and the water is filled in the nuclear reactor pressure vessel 3 and in the well pool 10 to shield the radioactive rays and to prevent the diffusion of the radioactivity to the operation floor 9. After that, the steam dryer 5 and the vapor-liquid separator 6 are lifted out from the nuclear reactor pressure vessel 3 according to the overhead crane 8 and are laid in the water in DS pool 7. Further, the steam dryer 5 and the vapor-liquid separator 6 are provided temporally and are stored. In this case, the vapor-liquid separator 6 and a shroud head are formed as one body and are lifted out. Further, the vapor-liquid separator 6 and the shroud head are laid in the water in DS pool 7 and are stored. Next, the fuels in the nuclear reactor pressure vessel 3 are taken out from the nuclear reactor pressure vessel 3 to a suitable place and are stored. Next, the water in the well pool 10 and the nuclear reactor pressure vessel 3 is drawn out and the radioactivity cleaning working in the nuclear reactor pressure vessel 3 is carried out. Next, the curing sheet 63 which has closed the opening 61 of the nuclear reactor building 11 and the rolling system shutter 62 are operated to close the opening 61 and the opening 61 is performed to have an opened state. After that, until the restoration of the opening 61, the pressure in the space of the nuclear reactor building 11 at least the operation floor 9 is maintained to a negative pressure condition to have a lower pressure than the pressure in the outside of the nuclear reactor building 11. The maintaining means is carried out using a ventilation apparatus which is arranged at the space of the operation floor 9. Next, the lifting balance 51 is lifted up according to the large scale lifting machine 91 and the hoisting device 52 and the cask 41 are lifted up at the same time, and further the lifting balance 51, the large scale lifting machine 91 and the hoisting deice 52 are lifted from the opening 61 and to carry out to approach to the well pool 10. Accordingly, the pull-up supporting condition between the lifting balance 51 according to the large scale lifting machine 91 and the large scale lifting machine 91 and the hoisting device 52 is maintained. For this reason, the working, in which the lifting balance 51, the hoising device 52, and the cask 41 are separated from the large scale lifting machine 91 and are reached to the operation floor 9, is not carried out. With the above stated process, the carry-in of the empty cask 41 is performed. After the carry-in of the empty cask 41 has carried out, the opening 61 is performed to have a narrow opening in which the wire rope for lifting up the lifting balance 51 of the large scale lifting machine 91 can be passed through by closing the curing sheet 63 and the rolling system shutter 62. By combining the procedure for maintaining at the above stated negative pressure condition, the atmosphere in the nuclear reactor building 11 is prevented to the utmost from leaking to the outside of the nuclear reactor building 11. Next, the wire rope 13 is paid out according to the hoisting device 52 and the hook lifting down working is carried out to approach the hook 14 toward the shroud 1. Further, the nuclear reactor internal structure slinging working is carried out, in such a nuclear reactor internal structure slinging working, the wire rope 26 is paid out between a unitary structure which is constituted by the hook 14, the upper portion lattice plate and the shroud 1. Next, the lifting-up working for lifting up the wire rope 13 according to the hoisting device 52 is carried out and then the shroud 1 is pulled up and supported as shown in FIG. 5, and the shroud 1 is stored gradually to the inner side of the cask 41 and as a result the receipt in the cask working is carried out. Next, the bougie car 43 is run along to the rail 15 and is stopped just above the well pool 10. Then the cask bottom plate which is mounted on the bougie car 43 can be positioned just under the cask 41. Next, the ascend and descend table 19 of the receiving table 46 is pushed up according to the air pressure cylinder apparatus 18 and the ascend and descend table 19 is rotated toward the horizontal direction, then with the female screws 42b of the cask 41 the male screws 42a of the cask bottom plate 42 is engaged, the inlet port 27 of the cask 41 is closed, accordingly the cask hole enclosing working is finished. To more ensure the closing condition of the cask hole, a boundary portion between the cask bottom plate 42 and the cask 41 is performed to weld and to fix according to the welding manner and to carry out the seal welding. Further, the shroud 1 is lifted down on the cask bottom plate 42 according to the hoising device 52 and the respective wire ropes 13 and 26 are given a condition where the shroud 1 is given the tension where the shroud 1 is not failed down. The construction to which the hole closing working about the cask 41 is employed are exemplified according to the two examples shown in addition to those shown in FIG. 6(a) and FIG. 6(b), however in the constructions shown in FIG. 7(a) and FIG. 7(b), the cask bottom portion is formed with the faucet system and the closed condition is shown. The shroud 1 is lifted up to above from the floor of the operation floor 9, and on the bougie car 43 the cask bottom portion having the faucet structure 44a through the receiving table 46 is mounted on and the shroud 1 is run and moved at just under the cask 41. The cask bottom portion 42 is raised similarly to in the above, the faucet structure 44a is inserted into the cask 41 and after that the cask bottom portion 42 is rotated toward the horizontal direction. Then the cask bottom portion 42 is aligned to the position where the faucet structure 44b is fitted into faucet structure 44b at the cask side in the cask 41 and the receiving table 46 is retarded toward the lower portion from the cask bottom portion 42 and even those faucet structures between the cask 41 and the cask bottom plate 42 are meshed and fixed. According to the commands, the boundary portion between the cask 21 and the cask bottom plate 42 are fixed according to the welding manner or the sealing welding manner and then the closing condition of the inlet port 27 of the cask 41 is performed more surely. In the examples shown in FIG. 8(a) and FIG. 8(b), similarly to the examples shown in FIG. 6(a) and FIG. 6(b), the cask bottom portion 42 is positioning aligned by aligning to just under of the inlet port 27 of the cask 41. After that, at the position of the bolt 24 a bolt through-out hole 45a is rotated the cask bottom plate 42 toward the horizontal direction by the cask bottom plate 42 according to the receiving table 46 to coincide with the upward and downward directions. After that by the receiving table 46 the cask bottom plate 42 is arisen and the bolt 24 is passed through the bolt passing-through hole 45a and the screw portion of the bolt 24 which is come out toward the lower portion from the bolt passing-through hole 45a is engaged with the nut 25 and the nut 25 is tied up and then at the lower end of the cask 41 the cask 41 is adhered and accordingly the hole closing working is carried out. In this case, according to the demands the boundary portion of the cask 41 and the cask bottom plate 42 is fixed to and seal-welded according to the welding manner and then the sealing condition to the inlet port 27 of the cask 41 can be performed surely. Further, when the sealing condition of the shroud 1 according to the cask 41 is performed surely to transfer, according to the hoisting device 52 the shroud 1 is received in the cask 41 and after the hole closing working of the inlet port 27 of the cask 41, the wire rope 13 of the hoisting device 52 is pulled out and the shroud 1 is set down on the cask bottom plate 42. The hook 14 and the wire rope 13 together is taken out from an upper portion passing-through hole 54 and then the hole closing working of the upper portion passing-through hole 54 is carried out. The hole closing working may be the screw system in which the cover is screws to the upper portion passing-through hole 54 or may be the welding system in which the cover is welded to the upper portion passing-through hole 54 or may be flange system in which using the bolt and the nut the cover is fastened to the cask 41. With the above stated structure, now the element in which the atmosphere in the cask 41 leaks to the outside of the cask 41 become nothing. When the cask hole closing working has finished, next, as shown in FIG. 9(a) and FIG. 9(b), a lifting rope 92 is wound out from a large scale lifting machine 91 according to the large scale lifting machine 91 and a hook block 93 of the large scale lifting machine 91 which is lifted to the lifting rope 92 is lifted near to the opening 61. With this structure, further the lifting balance 51 which is lifted up from the hook block 93, the hoisting device 52 and the cask 41 are lifted near to the opening 61. Next, it will enter the opening passing-through working, firstly the rolling system shutter 62 is opened and further the opening 61 is opened, next by the large scale lifting machine 91 the lifting rope 92 is wound up further from the large scale lifting machine 91 and to the opening 61 the lifting balance 51, the hoisting device 52 and the cask 41 are passed through. As shown in FIG. 11, the rolling system shutter 62 is closed and further then the opening 61 is closed. After that the above stated opening passing-through working is performed, the lifting balance 51, the hoisting device 52 and the cask 41 are lifted up toward the upper portion from the nuclear reactor building 11 and then the lifting up working in which the lifting balance 51, the hoisting device 52 and the cask 41 are carried out to the upper portion of the outside of the nuclear reactor building 11 is carried out. In the condition in which the rolling system shutter 62 is opened, from the opening 61 the atmosphere in the nuclear reactor building 11 is tried to leak toward the outside of the nuclear reactor building 11, however the pressure in the nuclear reactor building 11 is managed to a lower negative pressure condition than the pressure in the outside of the nuclear reactor building 11. Accordingly, the leakage of the atmosphere in the nuclear reactor building 11 is checked and the restraint of the radioactivity diffusion toward the outside of the atmosphere in the nuclear reactor building 11 can be strengthened. This rolling system shutter 62 is formed by making the large scale of a construction of a diaphragm mechanism of a camera and the opening 61 can be opened according a move of four diaphragm blades toward a radial direction. In place of the rolling system shutter 62, as shown in FIG. 10(a) and FIG. 10(b), the shape of the opening 61 can be formed with a quadrangle shape and from four sides of the quadrangle shape directing toward a center of the opening 61, four curing sheets 63 are spread by proceeding to the horizontal direction and the opening 61 is closed, in reversely by folding the four curing sheets 63 the opening is opened, according a construction for opening and closing the opening 61 can be employed. Another means for preventing the leakage of the atmosphere to the minimum through the opening 61 from in the nuclear reactor building 11, there is a method for enclosing the cask 41, as shown in FIG. 10(a) and FIG. 10(b). Namely, in the above stated another method, firstly the cask 41 is lifted by approaching the cask 41 to the opening 61 through the large scale lifting machine 91 and holding under this condition the lifting balance 51, the hoisting machine 52 and the cask 41 are enclosed by a sheet which is installed sealable to four sides of the opening 41 and between a space of the cask 41 from the sheet 64 and a space of the operation floor at an outside the communication of the atmosphere can be prevented. After that, the curing sheet 63 is folded at a side of the four sides of the opening 41 and the opening 61 is opened and after the lifting balance 51, the hoisting machine 52 and the cask 41 are lifted at a height of the cask 41 as shown in FIG. 11, and then the shroud 1 is stored from the nuclear reactor building 11 and are carried out the outside. Even when the opening 61 is opened, since there is a possibility in which only the atmosphere at the space of the cask 41 side from the sheet is leaked at the maximum, a safety can be attained, and further in a case of the open of the opening 61, even the rush-in matters from the outside of the nuclear reactor building 11 and the atmosphere are entered into the space of the operation floor 9, the rush-in matters and the atmosphere are enclosed by the sheet 64, accordingly the diffusion of the atmosphere in the space of the operation floor 9 can be prevented. Next, after the lifting of the cask 41 which has stored the shroud 1 is carried out toward the upper portion of the nuclear reactor building 11, by swirling the boom of the large scale lifting machine the cask 41 is positioned at the just upper portion of an underground reservoir 81, accordingly the swirl working is carried out. Next, the cask 41 is fixed in the underground reservoir 81 and then the storage storing and fixing working is carried out. Next, the wire rope 12 is taken off from the cask 41 and the cask 41 is taken off from the lifting balance. Further, the wire rope 13 is cut off, for example, and the connection between the hoisting machine 52 and the shroud 1 is released, the slinging-out working is carried out, and next the inlet port of the underground reservoir 81 is covered and closed, then the carry-out working is finished. In a case of the decomposition of the atomic power plant station, in place of the above stated carry-out working a newly shroud is carried in the nuclear reactor pressure vessel 3 and then in this case the installation working is not accompanied with. However, in a case of the replace working of the shroud 1, after the finish of the carry-out working, the carry-in working of a newly shroud in the nuclear reactor building 11 is accompanied with. The above stated carry-in working is carried out in accordance with the working process which is indicated as the carry-in working at a right side of FIG. 13. Namely, first of all, the new shroud is transported at the goods receipt position where the new shroud can be lifted by a trailer etc., accordingly the nuclear reactor internal structure transportation working is carried out. Next, between a hook block 93 of the large scale lifting machine 91 and the newly shroud, the nuclear reactor internal structure slinging working for laying the wire rope is carried out. Next, the new shroud is lifted up at the goods receipt position according to the large scale lifting machine 91 and by swirling the boom of the large scale lifting machine 91 toward the horizontal direction the new shroud is positioned just above of the opening 61, according the lifting-up and swirling working is carried out. Next, the opening 61 is opened by operating the rolling system shutter 62 or the curing sheet 63 and the new shroud is lowered according to the large scale lifting machine 91 and the opening 61 is passed through and entered into the nuclear reactor building 11. Next, the opening 61 is closed, except for a clearance in which the lifting rope 92 can be passed through, according to the rolling system shutter 62 and the curing sheet 63, accordingly the lowering and opening passing-through working is carried out. In this above stated case, since the pressure in the nuclear reactor building 11 is managed to have the lower negative pressure management condition than the pressure in the outside of the nuclear reactor building 11, the leakage of the atmosphere in the nuclear reactor building 11 can be checked and the radioactivity diffusion toward the outside of the atmosphere in the nuclear reactor building 11 can be prevented. Next, the newly shroud is lifted down further and entered into the nuclear reactor pressure vessel 3 and this new shroud is set at the position where the previous established shroud 1 has existed, accordingly the nuclear reactor internal structure installation and setting working is carried out. Next, the wire rope which is laid out between the new shroud and the hook block 93 is taken out from the newly shroud, accordingly the slinging-out working is carried out. After that, the above stated hook block 93 is lifted out at the outside of the nuclear reactor building 11 and then the carry-in working is finished. After that, the opening is restored to the original state, accordingly the carry-in and carry-out use opening restoration working is carried out. Next, the large scale lifting machine 91 is decomposed and withdrawn. According to the invention, since the container which is lifted in the nuclear reactor building is positioned above the internal structure of the nuclear reactor pressure vessel under a lifted condition and the internal structure is inserted in the container under the lifted condition, and since in the nuclear reactor building, there are unnecessary to carry out an assembly of the container a lowering of the container to a floor in the nuclear reactor building, a horizontal move on the floor, a connection and a release to a lifting means of the container after the lowering, and a connection working during the lowering and further it can transfer to the lifting out working, leaving the container with the lifted condition the internal structure can be stored in the container and the internal structure can be carried out speedy at the outside of the nuclear reactor building, and further the container can shield the diffusions of the radioactive rays and the radioactivity from the internal structure, as a result the effects of the diffusion of the radioactivity in the nuclear reactor building and the restraint of the radiation exposure can be attained. According to the invention, as the container the cask is used. According to the invention, by accompanying the cask with the hoisting device the cask and the hoisting device are lifted in the nuclear reactor building, after the lifting-in according to the hoising device which is arranged at the outer side of the cask the internal structure can be lifted up from the nuclear reactor pressure vessel and the internal structure can be stored in the cask and the internal structure can be carried out more speedy at the outside of the nuclear reactor building and the radioactive rays in the cask from the internal structure can be shielded according to the cask, as a result the effects can be obtained such effects are that the hoisting device which does arranged at the outer side of the cask is not strongly receive radiation and it may be dispensed with to make little a part which becomes to a radioactive waste material. According to the invention, since the cask bottom portion member is carried in to the lower portion of the inlet port of the cask according to the bougie car and the inlet port of the cask is closed by the cask bottom portion member and the move of the cask bottom portion member is carried out according to the bougie car and further the cask is lifted up always and the space for enable to carry in the cask bottom portion to the lower portion of the inlet port of the cask is obtained easily, as a result the closure working can be carried out speedy, and also the inlet port of the cask can be closed at the height near to the operation floor, the effects in which the diffusion of the radioactivity into the nuclear reactor building and the restraint of radiation exposure can be attained more effectively. According to the invention, using the same crane since the lifting-out of the cask from the nuclear reactor building to the lifting-in to the reservoir can be carried out consistently, the carry-in working of the internal structure to the reservoir can be speedy by lessening the intermittent working. According to the invention, by limiting to the passing-through of the cask to the opening, the opening is opened widely according to the opening and closing apparatus and the leakage of the atmosphere in the nuclear reactor building to the outside of the nuclear reactor building which occurs by the open of the opening can be restrained and further the inside of the nuclear reactor building is formed to the negative pressure in comparison with the outside of the nuclear reactor building and the occurrence of the flow of the atmosphere from the opening to the outside of the nuclear reactor building can be deprived of and then the leakage of the atmosphere in the nuclear reactor building to the outside of the nuclear reactor building can be restrained from an aspect of the pressure, and further employing a complex means of the opening and closing apparatus and the pressure adjustment the leakage of the atmosphere in the nuclear reactor building to the outside of the nuclear reactor building can be deprived of, and as a result an effect in which the discharge of the radioactivity to the outside portion can be avoided at the utmost. According to the invention, in a case where the cask is lifted out to the outside of the nuclear reactor building through the opening, since the leakage of the atmosphere in the nuclear reactor building from the opening is shielded according to a sheet for enclosing the cask and since the leakage of the atmosphere in the nuclear reactor building from the opening is prevented, as a result an effect in which the discharge of the radioactivity to the outside portion can be avoided at the utmost. According to the invention, an effect in which the shroud as the internal structure is handled collectively and effectively by not subdividing the shroud can be obtained. According to the invention, since the internal structure in the nuclear reactor can be exchanged speedy and as a result an effect in which the time of the re-operation of the nuclear reactor using the renewed internal structure of the nuclear reactor can be hastened. According to the invention, in addition to the effect of the invention, the shroud as the internal structure is carried out collectively from the nuclear reactor building by not subdividing the shroud and as a result an effect in which the shroud is exchanged speedy can be obtained. According to the invention, the cask which is lifted by the crane from the outside of the nuclear reactor building is lifted together with the hoisting device in the nuclear reactor building from the opening of the nuclear reactor building, and the cask which is lifted in the nuclear reactor building and the hoisting device are held by chinning the crane and the hoisting device which is lifted up according to the crane lifts the internal structure and then the internal structure carried out the double chinning state, and the internal structure is lifted up further according to the hoisting device and drawn in the cask, after the internal structure is drawn in and stored, under the stored condition of the internal structure the internal structure and the cask are passed through together with the opening of the nuclear reactor building according to the crane and is lifted up, then the operation for carrying out the nuclear reactor building to the outside can be obtained. According to this operation, since the internal structure is stored in the cask and is treated, the scattering of the radioactive rays and the radioactivity material from the internal structure can be restrained according to the cask and under the chinning condition of the hoisting device and the cask according to the crane the storing working of the internal structure in the cask can be carried out, and as a result an effect in which the internal structure can be treated speedy without the accompanying of the attachment and detachment working of the cask to the crane in the nuclear reactor building can be attained. According to the invention, since the inlet port of the lower end of the cask is closed according to the cask bottom plate, the radiation exposure of the operators and the diffusion of the radioactive material from the internal structure can be restrained. According to the invention, since the working for closing the inlet port of the cask is carried out speedy using the boggier car, an effect for providing the handling apparatus of the internal structure of the nuclear reactor in which the more speedy carry-out of the internal structure of the nuclear reactor can be provided. According to the invention, an effect in which the shroud as the internal structure can be handled speedy by not subdividing the shroud can be obtained.
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062696297	claims	1. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: (a) at least one coaxial cable segment having an inner conductor and an outer conductive shell positioned about said inner conductor, together with spacer material positioned between said inner conductor and said outer conductive shell, which material can readily vaporize upon the application of a high voltage pulse applied thereto; and (b) thruster control means for applying said high voltage pulse across said spacer material. (a) a plurality of propellant modules, each module comprising a coaxial cable segment having an inner conductor and an outer conductive shell positioned about said inner conductor together with spacer material positioned between said inner conductor, and said outer conductive shell, which material can readily vaporize upon the application of a high voltage pulse applied thereto; and (b) a single thruster control means for selectively applying said high voltage pulse across spacer material of coaxial cable segments of selected ones of said modules. (a) a plurality of propellant modules, each module comprising a first and second electrode with spacer material positioned between said first and second electrode, which spacer material can readily vaporize upon the application of a high voltage pulse applied thereto; and (b) a single thruster control means for selectively applying electrical energy stored within a single energy storage capacitor across spacer material of selected ones of said modules. a) spaced coaxial conductors having an inner conductor and an outer shell conductor positioned about said inner conductor, which conductors are separated by propellant spacer material, which material can ablate or vaporize upon application of a high voltage pulse thereto and b) thruster control means for applying said high voltage pulse to said conductors across said propellant spacer material. a) spaced coaxial spaced conductors having an inner conductor and an outer shell conductor positioned about said inner conductor, which conductors are separated by propellant spacer material, which material can ablate or vaporize upon application of a high voltage pulse applied thereto, b) a first circuit having a first switch electrically connecting said spaced conductors, c) a pulse generating circuit having a power supply connected across a capacitor, d) a pulse discharge circuit having a second switch also connected across said capacitor, said pulse discharge circuit being electrically connected to said first circuit by voltage step-up means, such that upon closing said first switch and then closing said second switch, said capacitor delivers a high voltage pulse through said pulse discharge circuit and across said conductors ablating or vaporizing a portion of said spacer therebetween, generating thrust. 2. The thruster of claim 1 wherein said spacer material comprises a tetrafluroethylene polymer. 3. The thruster of claim 1 wherein said high voltage pulse has a voltage of at least 1000 volts. 4. The thruster of claim 2 wherein said high voltage pulse has a voltage of at least 1000 volts. 5. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: 6. The thruster of claim 5 wherein said spacer material comprises a tetrafluroethylene polymer. 7. The thruster of claim 5 wherein said high voltage pulse has a voltage of at least 1000 volts. 8. The thruster of claim 6 wherein said high voltage pulse has a voltage of at least 1000 volts. 9. The thruster of claim 5 wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 10. The thruster of claim 6 wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 11. The thruster of claim 7 wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 12. The thruster of claim 8 wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 13. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: 14. The thruster of claim 13 wherein said spacer material comprises a tetrafluroethylene polymer. 15. The thruster of claim 13 wherein discharge of said energy storage capacitor applies a voltage pulse of at least 1000 volts across said spacer material. 16. The thruster of claim 14 wherein discharge of said energy storage capacitor applies a voltage pulse of at least 1000 volts across said spacer material. 17. The thruster of claim 13 wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 18. The thruster of claim 14 wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 19. The thruster of claim 15 wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 20. The thruster of claim 16 wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 21. A thruster for a spacecraft comprising, 22. The thruster of claim 21 wherein said spacer is selected from the group of ablative material, solid material and copolymer material. 23. The thruster of claim 21 wherein commercially available RF coaxial cable is employed as said coaxial conductors. 24. A compact thruster for a spacecraft comprising,
050193279	claims	1. A nuclear reactor fuel assembly transfer basket with a side access loading and unloading port for fuel assembly transfer service within a pool type nuclear reactor, comprising: a generally vertically positioned hollow cylindrical body affixed to a depending support means and having an elongated side access port extending substantially the length of the cylindrical body, said generally vertically positioned cylindrical body having a lower end annular base member with a conical shaped central opening extending vertically therethrough, and an upper end semicircular cap member having a central opening extending vertically therethrough with an upper annular surface sloping downward towards the central opening with an adjoining intermediate portion having an angular peripheral edge partially surrounding the central opening and an adjoining lower semicircular portion. a generally vertically positioned hollow cylindrical body affixed to a manipulable depending support means and having an elongated side access port extending the length of the cylindrical body, said generally vertically positioned cylindrical body having a lower end annular base member with a conical shaped central opening concentric with the central axis of the cylindrical body extending vertically therethrough, and an upper end semicircular cap member having a central opening concentric with the central axis of the cylindrical body extending vertically therethrough with an upper annular surface sloping downward towards the central opening with an adjoining intermediate portion having an angular peripheral edge partially surrounding the central opening and an adjoining lower semicircular portion. a generally vertically positioned hollow cylindrical body affixed to a manipulative depending support means movable in vertical directions and having an elongated side access port extending the length of the cylindrical body, said generally vertically positioned cylindrical body having a lower end annular base member with a conical shaped central opening concentric with the central axis of the cylindrical body extending vertically therethrough and sloping inward in the downward direction, and an upper end semicircular cap member having a central opening concentric with the central axis of the cylindrical body extending vertically therethrough with an upper annular surface sloping downward and inward towards the central opening and an adjoining intermediate portion comprising a flat horizontal semi-circular plane area extending partially around the central opening and having a peripheral vertical edge extending upward from said plane are of a partial hexagonal cross-section and an adjoining lower semicircular portion. 2. The nuclear reactor fuel assembly transfer basket of claim 1, wherein the conical shaped central opening extending vertically though the lower end annular base member slopes inward and downward. 3. The nuclear reactor fuel assembly transfer basket of claim 1, wherein the intermediate portion of the upper end semicircular cap member comprises a flat horizontal semiannular plane area extending partially around the central opening and a peripheral vertical edge of a partial hexagonal cross-section. 4. The nuclear reactor fuel assembly transfer basket of claim 1, wherein the central openings extending vertically through the lower end annular base member and the upper end semicircular cap member of the hollow cylindrical body are aligned and concentric with the central axis of the hollow cylindrical body. 5. A nuclear reactor fuel assembly transfer basket with a side access loading and unloading port for fuel assembly transfer service within a pool type nuclear reactor, comprising: 6. The nuclear reactor fuel assembly transfer basket of claim 5, wherein the conical shaped central opening extending vertically through the lower end annular base member slopes inward in the downward direction. 7. The nuclear reactor fuel assembly transfer basket of claim 5, wherein the intermediate portion of the upper end semicircular cap member comprises a flat horizontal semicircular plane area extending partially around the central opening in the cap member with a peripheral vertical edge extending upward from said plane area of a partial hexagonal cross-section. 8. The nuclear reactor fuel assembly transfer basket of claim 5, wherein the manipulable depending support means having the generally vertically positioned hollow cylindrical body affixed thereto is moveable in vertical directions. 9. The nuclear reactor fuel assembly transfer basket of claim 5, wherein the manipulable depending support means having the generally vertically positioned hollow cylindrical body affixed thereto is a metal tape. 10. A nuclear reactor fuel assembly transfer basket with a side access loading and unloading port for fuel assembly transfer service within a pool type nuclear reactor vessel, comprising:
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	abstract	This disclosure describes a method for metallurgically bonding a complete leak-tight enclosure to a matrix-type fuel element penetrated longitudinally by a multiplicity of coolant channels. Coolant tubes containing solid filler pins are disposed in the coolant channels. A leak-tight metal enclosure is then formed about the entire assembly of fuel matrix, coolant tubes and pins. The completely enclosed and sealed assembly is exposed to a high temperature and pressure gas environment to effect a metallurgical bond between all contacting surfaces therein. The ends of the assembly are then machined away to expose the pin ends which are chemically leached from the coolant tubes to leave the coolant tubes with internal coolant passageways.
	description	This application is a continuation of U.S. patent application Ser. No. 12/912,557, filed Oct. 26, 2010, now U.S. Pat. No. 8,059,784, entitled, “PORTABLE ORTHOVOLTAGE RADIOTHERAPY”; which is a continuation of U.S. patent application Ser. No. 11/833,939, filed Aug. 3, 2007, now U.S. Pat. No. 7,822,175, entitled, “PORTABLE ORTHOVOLTAGE RADIOTHERAPY”; which claims priority benefit from U.S. Provisional Application No. 60/933,220, filed Jun. 4, 2007, entitled, “PORTABLE ORTHOVOLTAGE RADIOTHERAPY”; U.S. Provisional Application No. 60/922,741, filed Apr. 9, 2007, entitled, “RADIATION THERAPY SYSTEM FOR THE TREATMENT OF MACULAR DEGENERATION”; U.S. Provisional Application No. 60/869,872, filed Dec. 13, 2006, entitled, “XRAY TREATMENT SYSTEM”; U.S. Provisional Application No. 60/862,210, filed Oct. 19, 2006, entitled, “METHODS AND DEVICE FOR NON-INVASIVE ROBOTIC TARGETING OF INFLAMMATORY LESIONS USING RADIATION”; U.S. Provisional Application No. 60/862,044, filed Oct. 18, 2006, entitled, “METHODS AND DEVICES FOR NON-INVASIVE ROBOTIC TARGETING OF RETINAL LESIONS”; and U.S. Provisional Application No. 60/829,676, filed Oct. 16, 2006, entitled, “METHODS AND DEVICES TO APPLY FOCUSED ENERGY TO BODY REGIONS”; the entirety of each of which are incorporated herein by reference. 1. Field of the Inventions This disclosure relates to the treatment of ocular disorders using targeted photon energy. In particular, the present disclosure relates to an apparatus, systems, and methods for image-guided low energy x-ray therapy of ocular structures. 2. Description of the Related Art Macular degeneration is a condition where the light-sensing cells of the macula, a near-center portion of the retina of the human eye, malfunction and slowly cease to work. Macular degeneration is the leading cause of central vision loss in people over the age of fifty years. Clinical and histologic evidence indicates that macular degeneration is in part caused or results in an inflammatory process which ultimately causes destruction of the retina. The inflammatory process can result in direct destruction of the retina or destruction via formation of neovascular membranes which leak fluid and blood into the retina, quickly leading to scarring. Most treatments for macular degeneration are aimed at stopping the neovascular (or “wet”) form of macular degeneration rather than geographic atrophy, or the “dry” form of Age-related Macular Degeneration (AMD). All wet AMD begins as dry AMD. Indeed, the current trend in advanced ophthalmic imaging is that wet AMD is being identified prior to loss of visual acuity. Treatments for macular degeneration include the use of medication injected directly into the eye (Anti-VEGF therapy), laser therapy in combination with a targeting drug (photodynamic therapy); other treatments include brachytherapy (the local application of a material which generates beta-radiation). It would be advantageous to provide a treatment for ocular disorders which irradiates specific regions of the eye without substantially exposing the rest of the eye to radiation. In some embodiments described herein, a radiotherapy system is disclosed that may be used to treat a wide variety of medical conditions relating to the eye. For example, the system may be used, alone or in combination with other therapies, to treat macular degeneration, diabetic retinopathy, inflammatory retinopathies, infectious retinopathies, tumors in the eye or around the eye, glaucoma, refractive disorders, cataracts, post-surgical inflammation of any of the structures of the eye, ptyrigium, and dry eye. In some embodiments described herein, radiotherapy (or externally applied radiation therapy) is used for treatment of macular degeneration, and a standard treatment for macular degeneration is disclosed. Radiotherapy for treatment of macular degeneration presents several complications. For example, the eye contains several critical structures, such as the lens and the optic nerve, that can possibly be damaged by excessive exposure to radiation. The application of external beam therapy is limited by devices and methodologies used to apply the therapy. These devices and methodologies are older radiation technologies used to treat conditions such as tumors anywhere in the body and were not developed specifically for ocular radiation therapy. In addition, logistics are difficult as far as patient recruitment and administration of treatments because such treatment devices are borrowed from and displace oncologic therapies. Retinal radiotherapy trials have shown stabilized or improved visual acuity without any significant toxicity. Radiation has also been shown to dry up neovascular membranes in patients and stabilize vision. However, due to limitations in the treatment of macular degeneration using radiotherapy including localization of the region to be treated as well as specific application of the radiation to the region to be treated, retinal radiotherapy often irradiates the entire retina, which is both unnecessary and possibly harmful. Brachytherapy for wet AMD is also a powerful therapy to treat wet AMD (Neovista, Inc., Press Release, March 2007, the entirety of which is incorporated herein by reference). A major limitation of this treatment is that it requires invasive procedures involving partial removal of the vitreous fluid of the posterior chamber of the eye to place the brachytherapy probe. In addition, it cannot be fractionated because of the invasiveness required to deliver it. Furthermore, it would be difficult to apply this therapy to patients who do not yet have vision loss because of the potential complications from the procedure. Other diseases of the eye include glaucoma. In this disease, surgery is often the second line of therapy after pharmaceutical therapy. Procedures such as trabeculoplasty, trabeculotomy, canaloplasty, laser iridotomy, placement of shunts, and other procedures all suffer from a short-lived effect because of scar formation as a result of the surgical trauma. Anti-inflammatory drugs appear to offer a palliative and/or preventative solution to the chronic scarring that occurs after these procedures; however, the drugs have to be given several times per day and are associated with their own side effect profile such as seepage into unwanted regions of the eye. Radiation (10 Gy) can be beneficial in the prevention of scarring after glaucoma surgery (Kirwan, et. al., Effect of Beta Radiation on Success of Glaucoma Drainage Surgery in South Africa: randomized controlled trial; British Medical Journal, Oct. 5, 2006, the entirety of which is herein incorporated by reference). Capsular opacification is a common occurrence after cataract procedures with placement of intra-ocular lenses. This scarring is caused by trauma from the surgery, proliferation of lens cells, and material incompatibility. In some embodiments, the radiation treatment system is used concomitantly with laser therapy. That is, rather than using a laser solely for pointing the x-ray device to the ocular target of choice, the laser is used for both pointing and therapy. In these embodiments, the laser preferably includes at least one additional energy or wavelength suitable for therapy of an ocular structure. The x-ray is preferably applied to the same region as the laser so as to prevent excessive scarring around the laser therapy. In some embodiments of this disclosure, the electromotive and ocular imaging systems are utilized but laser therapy is the sole radiation energy source used for treatment. In this embodiment, the ability of the system to focus radiation by passing the photons through the sclera from different angles to structures deep to the sclera can be utilized to treat diseases of the anterior chamber or posterior chamber with laser radiation while keeping the x-ray generation system off; indeed in some embodiments of the system, the x-ray generator is not included in the system. In these embodiments, the eye model, tracking, control, and focusing systems for the x-ray therapy are utilized for therapeutic laser therapy. In certain embodiments, a device using a treatment planning system is disclosed for providing targeted radiotherapy to specific regions of the eye. The treatment planning system integrates physical variables of the eye as well as disease variables from the physician to direct the x-ray system to deliver therapy to the ocular structures. The device applies narrow beams of radiation from one or more angles to focus radiation to a targeted region in or on the eye. In certain embodiments, the device may focus radiotherapy to structures of the posterior eye, such as the retina. In certain embodiments, the device may focus radiotherapy to structures of the anterior region of the eye, such as the sclera. The treatment planning system allows for planning of the direction of the beam entry into the eye at different points along the sclera. The unique anatomy of each individual is integrated into the treatment planning system for accurate targeting, and in some examples, automated positioning of the x-rays of the device. In some embodiments described herein, a treatment system is provided for delivering radiation to a patient. The system preferably includes an eye model derived from anatomic data of a patient's eye, an emitter that emits a radiation beam, and a position guide, coupled to the emitter, that positions, based on the eye model, the emitter with respect to a location on or in the eye, such that the radiation beam is delivered to a target on or in the eye. In some embodiments, the location comprises the target. The emitter can be configured to deliver the radiation beam with a photon energy between about 10 keV and about 500 keV or to deliver an radiation beam adjustable between about 25 keV and about 100 keV. In some embodiments, the radiation beam includes an x-ray beam. In some embodiments, the system further includes a planning module configured to determine, based on the eye model, at least two of a beam target, a beam intensity, a beam energy, a beam trajectory, a treatment field size, a treatment field shape, a distance from the emitter to the target, an exposure time, and a dose. The position guide, in some embodiments, positions the emitter, based on information from the planning module, such that the emitter directs a first radiation beam at a first position through a first portion of the eye to a treatment region within the eye. The position guide preferably positions the emitter, based on information from the planning module, such that the emitter directs a second radiation beam at a second position through a second portion of the eye to the treatment region within the eye. In some embodiments, the planning module is adapted to receive input from a user, the input affecting an output of the planning module. In some embodiments, the system includes a sensing module that senses a position of the eye and relays information concerning the position of the eye to the planning module. The system includes, in some embodiments, a sensing module that senses a position of the eye and relays information concerning the position of the eye to the position guide. The sensing module can include a portion that physically contacts the eye, which can include a lens positionable on or over the cornea of the eye. The sensing module can, in some embodiments, optically sense the position of the eye with, for example, a laser. In some embodiments, the system also includes a collimator that collimates the radiation beam to a width of from about 0.5 mm to about 6 mm. The collimated beam can also have a penumbra of less than about ten percent at a distance up to about 50 cm from the collimator. The position guide, in some embodiments, is configured to position the emitter, in use, at a first distance within 50 cm of the target, such that the emitter delivers the radiation beam to the target from the first distance. In some embodiments, a collimator is positioned, in use, to within about 10 cm of the target when the radiation beam is delivered to the target. The system can further include a detector that detects if the patient's eye moves such that the radiation beam is not directed to the target. In some embodiments, the emitter is configured to automatically not emit the radiation beam if the patient's eye moves out of a predetermined position or range of positions. Some embodiments include a laser emitter that emits a laser beam that passes through a collimator and is directed toward the eye. Some embodiments described herein disclose a system for delivering radiation to an eye that includes an eye model derived from anatomic data of a patient's eye, an emitter that delivers an x-ray beam to the eye with an energy from about 10 keV to about 500 keV, a position guide, coupled to the emitter, that positions, based on the eye model, the emitter with respect to a location in or on the eye, to deliver the x-ray beam to a target in or on the eye, and a planning module that determines at least two parameters of treatment based on the model of the eye. In some embodiments, the at least two parameters include two of a beam target, a beam intensity, a beam energy, a beam trajectory, a treatment field size, a treatment field shape, a distance from the emitter to the target, an exposure time, and a dose. The position guide, in some embodiments, is configured to direct a first x-ray beam from a first position to a first region of a sclera of the eye to target a region of the eye, and is further configured to direct a second x-ray beam from a second position to a second region of the sclera to target substantially the same region of the eye. In some embodiments, the region of the eye is at least one of the macula, the sclera, the trabecular meshwork, and a capsule of the lens of the eye. The system can further include a collimator that collimates the x-ray beam. In some embodiments, the collimator is configured to collimate the x-ray beam to a width of from about 0.5 mm to about 6 mm, and in some embodiments, the system is configured to produce an x-ray beam having a penumbra of less than about five percent within a distance, from the collimator to the target, of about 50 cm. The emitter, in some embodiments, is configured to deliver an x-ray beam with a photon energy between about 25 keV and about 150 keV. In some embodiments, the collimator is positioned, in use, to within about 10 cm of the target when the x-ray beam is delivered to the target. In some embodiments, a treatment system for delivering radiation to a human being is provided, the system including an eye model derived from anatomic data of a patient's eye; an emitter that delivers an x-ray beam to the eye; and means for positioning the emitter, with respect to a location on or in the eye, to deliver the x-ray beam to a target on or in the eye, the means being coupled to the emitter, and the positioning of the emitter being based on the eye model. Some embodiments provide a treatment system for delivering radiation to a patient that includes an emitter that generates an radiation beam, and a position guide, coupled to the emitter, operable to positions the emitter with respect to a location on or in the eye, to deliver the radiation beam to a target on or in the eye, wherein the emitter is placed within 50 cm of the target. In some embodiments, the system further includes a collimator coupled to the emitter, the collimator being placed, in use, to within 10 cm of the target when the emitter emits the radiation beam. In some embodiments, the system further includes a collimated laser emitter that is coupled to the emitter. In some embodiments described herein, a method of treating macular degeneration of an eye is disclosed. The method preferably includes providing a model of an eye of a patient with anatomic data obtained by an imaging apparatus, producing an x-ray beam with a width of from about 0.5 mm to about 6 mm and having a photon energy between about 40 keV and about 100 keV, and in some embodiments between about 40 keV and about 250 keV, directing the x-ray beam such that the beam passes through the sclera to the retina of the eye, and exposing the retina to from about 1 Gy to about 40 Gy of x-ray radiation. In some embodiments, the method provides that at least one of the x-ray beam width, photon energy, and direction of the x-ray beam is determined based on the model of the eye. The method further provides, in some embodiments, that the retina is exposed to from about 15 Gy to about 25 Gy of x-ray radiation. In some embodiments, treatment with the x-ray radiation can be fractionated, and a planning system can keep track of the quantity and location of prior treatments. In some embodiments, the method includes reducing neovascularization in the eye by exposing the retina to the radiation. The method may further include administering to the patient at least one of heating, cooling, vascular endothelial growth factor (VEGF) antagonist, a VEGF-receptor antagonist, an antibody directed to VEGF or a VEGF receptor, microwave energy, laser energy, hyperbaric oxygen, supersaturate oxygen, ultrasound energy, radiofrequency energy, and a therapeutic agent, prior to, or after, exposing the retina to the radiation. The method further includes, in some embodiments, directing a first x-ray beam to pass through the sclera to the retina from a first position external to the eye, and directing a second x-ray beam to pass through the sclera to the retina from a second position external to the eye. In some embodiments, the x-ray beam is directed to pass through a pars plana of the eye. The x-ray beam is, in some embodiments, directed to a macula of the eye. Some embodiments herein describe a method of treating an eye of a patient that includes providing a model of the eye based on anatomic data obtained by an imaging apparatus, producing a first x-ray beam and a second x-ray beam, each beam having a width of from about 0.5 mm to about 6 mm, directing the first x-ray beam such that the first beam passes through a first region of a sclera of the eye to a target of a retina, and directing the second x-ray beam such that the second beam passes through a second region of the sclera to substantially the same target of the retina as the first beam, wherein the first region and second region of the sclera through which the first beam and second beam pass are selected based on the model of the eye. In some embodiments, a trajectory of the first beam is determined based on the model of the eye, and in some embodiments, the directing of the first x-ray beam and the directing of the second x-ray beam occur sequentially. In some embodiments, the first x-ray beam and the second x-ray beam have photon energies of from about 25 keV to about 100 keV. Centers of the first and second x-ray beams, in some embodiments, are projected through a point on the sclera at a distance of from about 0.5 mm to about 6 mm from a limbus of the eye. In some embodiments, the method further includes administering to the patient at least one of heating, cooling, VEGF antagonist, a VEGF-receptor antagonist, an antibody directed to VEGF or a VEGF receptor, microwave energy, radiofrequency energy, laser energy, and a therapeutic agent, prior to, concurrently with, or subsequent to the directing of the first x-ray beam. The x-ray beam, in some embodiments, is produced by an x-ray source positioned less than about 50 cm from the retina. In some embodiments, the x-ray beam is emitted from a source having an end that is placed within about 10 cm of the eye. In some embodiments, the retina is exposed to about 15 Gy to about 25 Gy in some embodiments, and, in some embodiments to about 35 Gy, of x-ray radiation during one treatment session. Some embodiments described herein relate to a method of treating an eye of a patient that includes providing a model of the eye based on anatomic data obtained by an imaging apparatus, producing a first x-ray beam and a second x-ray beam, each beam having a width of from about 0.5 mm to about 6 mm, directing the first x-ray beam such that the first beam passes through a first region of the eye to a target within the eye, and directing the second x-ray beam such that the second beam passes through a second region of the eye to substantially the same target within the eye, wherein the first region and second region of the eye through which the first beam and second beam pass are selected based on the model of the eye. The target, in some embodiments, includes the lens capsule of the eye. In some embodiments, the target includes the trabecular meshwork of the eye or a tumor. In some embodiments, the first region comprises the cornea of the eye. In some embodiments, the first x-ray beam and the second x-ray beam have photon energies of from about 25 keV to about 100 keV. In some embodiments, the first and second x-ray beams are collimated by a collimator positioned within 10 cm of the eye, and in some embodiments, the x-ray beams are produced by an x-ray source positioned within 10 cm of the eye. The x-ray source can also be positioned within 50, 40, and/or 10 cm of the eye. In some embodiments, the first region of the eye includes a first region of a sclera and the second region of the eye comprises a second region of the sclera, and an edge-to-edge distance from the first region of the sclera to the second region of the sclera is from about 0.1 mm to about 2 mm. In some embodiments, the first and second x-ray beams are directed from a nasal region external to the eye. Some methods further include aligning the center of the patient's eye with the x-ray radiotherapy system. Some methods also include developing a plan to treat a macular region using the model of the eye, wherein the first and second x-ray beams overlap at the macular region, and the first and second x-ray beams are collimated to from about 0.5 mm to about 6 mm. Some embodiments described herein disclose a method of applying radiation to the retina of a patient's eye, the method including localizing the macula of the patient with an imaging device, linking the macula to a global coordinate system, and applying an external beam of radiation to the macula based on the coordinate system. Some embodiments described herein disclose methods, of applying radiation to a patient's eye, that include obtaining imaging data of at least a portion of a patient's eye; identifying, based on the imaging data, a location of a macula of the patient's eye; identifying a first location of a fiducial marker located in or on the eye; mapping the location of the macula, relative to the first location of the fiducial marker, in a coordinate system, thereby producing a mapped location of the macula in the coordinate system; positioning, based on the mapped location of the macula, a radiation source that applies radiation to the macula; and emitting the radiation from the positioned radiation source to the macula. In some embodiments, a contact lens that contacts the sclera and/or the cornea of the patient comprises the fiducial marker. The positioning of the radiation source is automated, in some embodiments, based on the coordinate system. The methods may also include repositioning the radiation source based on a movement of the fiducial marker to a second location of the fiducial marker. In some embodiments, the methods include, after the repositioning of the radiation source, emitting an additional radiation beam from the radiation source to the macula. In certain embodiments, after mapping the location of the macula, methods include detecting a movement of the eye. The methods also may include determining a relative relationship between a new location of the macula and the coordinate system after the detecting of the eye movement. Some embodiments further include relaying information about the new location of the macula to a positioner that changes a position of the radiation source, and in some embodiments, applying the radiation to a region of drusen in the eye. In some embodiments, the emitting the radiation comprises emitting a radiation beam. Some embodiments further include applying at least one additional radiation beam to the macula. In some embodiments, the radiation beam and the at least one additional radiation beam are applied simultaneously. In certain embodiments, the radiation beam and the at least one additional radiation beam are directed such that they intersect within a volume of tissue that includes the macula. The obtaining imaging data of the retina, in some embodiments, includes at least one of triangulation, interferometry, and phase shifting. In some embodiments, the imaging data is obtained with at least one of computed tomography, magnetic resonance imaging, optical coherence tomography, and positron emission tomography. Described herein are methods, of applying radiation to a patient's eye, that include obtaining imaging data of at least a portion of a patient's eye; identifying, based on the imaging data, a location of a macula of the patient's eye; identifying a first location of an anterior structure of the eye; mapping the location of the macula, relative to the first location of the anterior structure of the eye, in a coordinate system, thereby producing a mapped location of the macula in the coordinate system; positioning, based on the mapped location of the macula in the coordinate system, a radiation source to apply a dose of radiation to the macula; and emitting a radiation beam from the positioned radiation source to the macula. In certain embodiments, the anterior structure of the eye includes the sclera, and in some embodiments, the anterior structure of the eye includes at least one of a cornea, an anterior chamber, an iris, a conjunctiva, a pupil, an iridocorneal angle, a trabecular meshwork, a lens capsule, a prosthetic intraocular lens, a ciliary body, a ciliary muscle, a limbus, a pars plana, a scleral spur, and a lens of the eye. Some embodiments further include repositioning the radiation source based on a movement of the anterior structure to a second location of the anterior structure. Certain embodiments further include, after the repositioning of the radiation source, emitting an additional radiation beam from the radiation source to the macula. In some embodiments, obtaining imaging data of the retina includes at least one of triangulation, interferometry, and phase shifting. Some embodiments provide a method of treating a region of an eye of a patient that includes producing an x-ray beam with a width of from about 0.5 mm to about 6 mm and having a photon energy between about 40 keV and about 250 keV, directing the x-ray beam toward the eye region, and exposing the region to a dose of from about 1 Gy to about 40 Gy of x-ray radiation, thereby treating the region of the eye. In some embodiments, the method further includes providing a model of the eye with anatomic data obtained by an imaging apparatus, wherein at least one of a width of the x-ray beam, a photon energy of the x-ray beam, and a direction of the x-ray beam is determined based on the model of the eye. The region, in some embodiments, is exposed to from about 15 Gy to about 25 Gy of x-ray radiation, and in some embodiments, the region includes a retina of the eye. The treating can include reducing neovascularization in the eye by exposing the retina to the radiation, and/or substantially preventing progression from Dry Age-related Macular Degeneration (AMD) to neovascularization. In some embodiments, the method also includes administering to the patient at least one of heating, cooling, VEGF antagonist, a VEGF-receptor antagonist, an antibody directed to VEGF or a VEGF receptor, microwave energy, radiofrequency energy, a laser, a photodynamic agent, and a radiodynamic agent, and a therapeutic agent. Some embodiments further include directing a first x-ray beam to pass through a sclera to a retina from a first position external to the eye, and directing a second x-ray beam to pass through the sclera to the retina from a second position external to the eye. The x-ray beam, in some embodiments, is directed through a pars plana of the eye, and in some embodiments, the x-ray beam is directed to a macula of the eye. The x-ray beam can also be directed through a sclera of the eye to the macula of the eye. Some embodiments provide that the dose is divided between two or more beams, and in some embodiments, the dose is divided between two or more treatment sessions, each of said treatment sessions occurring at least one day apart. Some methods described herein further include determining a position of the eye relative to the x-ray beam during the exposing of the region to the x-ray radiation, and shutting off the x-ray beam if the position of the eye exceeds a movement threshold. Some methods of treating an eye of a patient described herein include providing a model of the eye based on anatomic data obtained by an imaging apparatus, directing a first x-ray beam such that the first beam passes through a first region of the eye to a target within the eye, and directing a second x-ray beam such that the second beam passes through a second region of the eye to substantially the same target within the eye, wherein the first region and second region of the eye through which the first beam and second beam pass are selected based on the model of the eye, and assessing a position of the eye during at least one of the administration of the first x-ray beam to the target, administration of the second x-ray beam to the target, and a period of time between administration of the first x-ray beam to the target and administration of the second x-ray beam to the target. Some methods provide that the assessing occurs during administration of the first x-ray beam to the target, and some methods further include ceasing or reducing administration of the first x-ray beam when the eye moves beyond a movement threshold. Some methods further include directing the second x-ray beam based on information from the assessing of the position of the eye. For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of the disclosure have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the disclosure. Thus, the disclosure may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. The present embodiments include systems and methods for treating a human eye with radiotherapy. Some embodiments described below relate to systems and methods for treating macular degeneration of the eye using radiotherapy. For example, in some embodiments, systems and methods are described for use of radiotherapy on select portions of the retina to impede or reduce neovascularization of the retina. Some embodiments described herein also relate to systems and methods for treatment of glaucoma or control wound healing using radiotherapy. For example, in some embodiments, systems and methods are described for use of radiotherapy on tissue in the anterior chamber following glaucoma surgery, such as trabeculoplasty, trabeculotomy, canaloplasty, and laser iridotomy, to reduce the likelihood of postoperative complications. In other embodiments, systems and methods are described to use radiotherapy to treat drusen, inflammatory deposits in the retina that are thought to lead to vision loss in macular degeneration. Localization of a therapy to the drusen to treat the surrounding inflammation may prevent the progression of dry and/or wet AMD. Alternatively, a laser therapeutic is applied to the drusen in combination (adjuvant therapy) with co-localized x-ray radiation to substantially the same spot where the laser touched down on the retina; the laser spot can create a localized heating effect which can facilitate radiation treatment or the laser spot can ablate the region and the radiation can prevent further scarring around the laser spot. Such combination therapy can enhance the efficacy of each therapy individually. Similarly, adjuvant therapies can include x-ray radiotherapy in combination with one or more pharmaceuticals or other radiotherapy enhancing drugs or chemical entities. Radiation can have both a broad meaning and a narrow meaning in this disclosure. Radiation, as used herein, is intended to have its ordinary meaning and is meant to include, without limitation, at least any photonic-based electromagnetic radiation which covers the range from gamma radiation to radiowaves and includes x-ray, ultraviolet, visible, infrared, microwave, and radiowave energies. Therefore, planned and directed radiotherapy can be applied to an eye with energies in any of these wavelength ranges. Radiotherapy can refer to treatment of disease using x-ray radiation; however, in this disclosure, radiotherapy is intended to have its ordinary meaning and is meant to include, without limitation, at least any type of electromagnetic radiation which uses photons to deliver an energy as a clinical therapy to treat a disease. X-ray radiation generally refers to photons with wavelengths below about 10 nm down to about 0.01 nm. Gamma rays refer to electromagnetic waves with wavelengths below about 0.01 nm. Ultraviolet radiation refers to photons with wavelengths from about 10 nm to about 400 nm. Visible radiation refers to photons with wavelengths from about 400 nm to about 700 nm. Photons with wavelengths above 700 nm are generally in the infrared radiation regions. Within the x-ray regime of electromagnetic radiation, low energy x-rays can be referred to as orthovoltage. While the exact photon energies of orthovoltage varies, for the disclosure herein, orthovoltage refers at least to x-ray photons with energies from about 20 KeV to about 500 MeV. The global coordinate system refers to a physical world of a machine or room. The global coordinate system is preferably a system relating a machine, such as a computer or other operating device, to the physical world or room that is used by the machine. The global coordinate system can be used, for example, to move a machine, components of a machine, or other things from a first position to a second position. The global coordinate system can also be used, for example, to identify the location of a first item with respect to a second item. In some embodiments, the global coordinate system is based on a one-dimensional environment. In some embodiments, the global coordinate system is based on a two-dimensional environment, and in some embodiments, the global coordinate system is based on three or more dimensional environments. Kerma, as used herein, refers to the energy released (or absorbed) per volume of air when the air is hit with an x-ray beam. The unit of measure for Kerma is Gy. Air-kerma rate is the Kerma (in Gy) absorbed in air per unit time. Similarly, “tissue kerma” rate is the radiation absorbed in tissue per unit time. Kerma is generally agnostic to the wavelength of radiation, as it incorporates all wavelengths into its joules reading. The beam shape is generally set by the last collimator opening in the x-ray path; with two collimators in the beam path, the secondary collimator is the last collimator in the beam path and can be called the “shaping collimator.” The first collimator may be called the primary collimator because it is the first decrement in x-ray power and generally is the largest decrement of the collimators; the second collimator can generally set the final shape of the x-ray beam. As an example, if the last collimator opening is a square, then the beam shape is a square as well. If the last collimator opening is circular, then the beam is circular. In some embodiments, there is one collimator which serves as the primary collimator as well as the beam shaping collimator. The penumbra refers to the fall-off in dose outside of the area of the last collimator and beam shape and size set by that collimator, typically measured at some distance from the last collimator. Penumbra, as used herein, has its ordinary meaning, which is meant to include, without limitation, the percentage of radiation outside the area of the last collimator when the x-ray beam reaches the surface of the eye or the target within the eye, whichever structure is the one being referenced with respect to the penumbra. The penumbra can incorporate the divergence of the beam as well as the scatter of the beam as it travels through the air and through the tissue. Ideally, the size of the primary beam is the same size as the last collimator to which the x-ray beam is exposed; that is, the penumbra is ideally zero. In reality, a penumbra of zero is difficult to achieve when the collimator is any distance from the target. However, the penumbra can be optimized, for example, by the shape of the collimator, the material of the collimator, the processing of the collimator material, the position of the anode of the x-ray tube, and the relative sizing of the collimator relative to the x-ray source. In some embodiments of the systems and methods provided herein, the penumbra area percentage at the entry point to the eye is less than about 10%. In some embodiments, the penumbra area percentage at the entry point to the eye is less than about 5%, and in some embodiments, the penumbra area percentage is less than about 1%. The penumbra can also refer to the percentage of radiation outside the zone of the shaping collimator at a target region of the macula. In some embodiments, the penumbra at the macula is less than about 40% and in some embodiments, the penumbra at the macula is less than about 20%, and in some embodiments, the penumbra at the macula is less than about 10% or less than about 5%. The penumbra can be incorporated into a treatment plan; for example, predictive knowledge of the penumbra can be utilized to plan the treatment. In one example, a finely collimated beam (e.g., having a 4 mm diameter) is applied to the sclera. The beam at the retina can be 5 mm (25% penumbra) or 6 mm (50% penumbra) diameter sufficient for coverage of a lesion. With this method, the structures of the anterior eye are minimally irradiated while the lesion at the retina is fully covered. In this embodiment, divergence of the x-ray beam is utilized for minimizing the exposure of the front of the eye without sacrificing a therapeutic dose to the retina. A related definition is that of “isodose fall-off” which refers to the dose fall-off independent of divergence angle of the beam. For example, in an ideal setting where there is no divergence angle, the isodose fall off is the same as penumbra. When divergence angle is introduced, the isodose fall-off is different from the penumbra, referring to the fall-off of dose around the shaping collimator beam without accounting for divergence angle. The isodose fall off is measured in Gy/mm, a linear distance from the edge of the collimator shape over a distance. Divergence angles typically follow a 1/R2 relationship assuming the source is a point source or close to a point source. Divergence angle is highly predictable for photons and can be calculated independently of scatter and the other physics which go into Monte Carlo simulations. Photons with shorter wavelengths correspond to radiation with higher energies. The higher-energy range of x-rays is generally in the MeV range and is generally referred to gamma x-rays, independent of how the radiation was generated. X-ray photons with relatively shorter wavelengths are referred to as orthovoltage x-rays. Higher energy radiation with shorter wavelengths corresponds to deeper penetration into target tissue, which is the reason that most applications using MeV energies require extensive shielding of the patient and surroundings. In some embodiments of this disclosure, x-rays typically used for diagnostic purposes, or low energy orthovoltage x-ray sources, can be used for therapy of ocular diseases and/or disorders which are relatively superficial in the patient such as breast, intra-operative radiation application, skin cancers, and other disorders such as peripheral vascular disease, implants, etc. X-rays typically used for diagnosis can be used for therapy by tightly collimating the x-ray beam into a thin beam of x-ray photons and directing the beam to the superficial region to be treated. If the disorder is deeper than several centimeters inside the body, then higher energy sources (e.g., MeV) may be preferred to enhance penetration of energy to the disorders. It is difficult to collimate MeV x-ray beams to small diameters with small penumbras because their very high speed photons cause secondary interactions with tissue including generation of secondary x-rays and other radiations. X-rays with energies lower than 500 KeV and even lower than 200 KeV can more appropriately be collimated to very small diameters. “Laser” energy is also composed of photons of different energies ranging from short wavelengths, such as ultraviolet radiation, up to long wavelengths, such as infrared radiation. Laser refers more to the delivery mechanism than to the specific wavelength of radiation. Laser light is considered “coherent” in that the photons travel in phase with one another and with little divergence. Laser light is also collimated in that it travels with relatively little divergence as is proceeds in space (penumbra). Light can be collimated without being coherent (in phase) and without being a laser; for example, lenses can be used to collimate non-x-ray light. X-ray light is typically collimated with the use of non-lens collimators, the penumbra defining the degree of successful collimation. Laser pointers are typically visualization tools, whereas larger, higher-flux lasers are utilized for therapeutic applications. In some embodiments, optics can be used, such as lenses or mirrors, and in some embodiments, there are no intervening optical elements, although collimators may be used. The two eye chambers are the anterior and posterior chambers. The anterior chamber includes the lens, the conjunctiva, the cornea, the sclera, the trabecular apparatus, the ciliary bodies, muscles, and processes, the iris, etc. The posterior chamber includes the vitreous humor, the retina, and the optic nerve. “Ocular diseases,” as used in this disclosure, is intended to have its ordinary meaning, and is meant to include at least disease of the anterior eye (e.g., glaucoma, presbyopia, cataracts, dry eye, conjunctivitis) as well as disease of the posterior eye (e.g., retinopathies, age related macular degeneration, diabetic macular degeneration, and choroidal melanoma). Drusen are hyaline deposits in Bruch's membrane beneath the retina. The deposits are caused by, or are at least markers of inflammatory processes. They are present in a large percentage of patients over the age of 70. Although causality is not known, drusen are associated with markers of the location where inflammation is occurring and where neovascularization has a high likelihood of occurring in the future; these are regions of so called “vulnerable retina.” Therefore, applying inflammation reducing radiation to the region may be beneficial to the patient. Radiation therapy has historically been marginally successful in treating disorders of the eye; for example, in a recent Cochrane meta-analysis review (Cochrane Database 2007(2), the entirety of which is incorporated herein by reference), the authors discussed the merits of radiation therapy for AMD. Among their general conclusions was as follows: ophthalmologists were reluctant to refer patients to the radiation oncologists for fear that they would lose their patients; it was difficult to localize the radiation source because specific methods were not used for the clinical protocol; and fractionation schemes and dosing was not standardized. Therefore, there is a great need for the systems and methods described in this disclosure. Brachytherapy described above appears to have a highly beneficial effect at least when combined with pharmaceutical therapy as an adjuvant therapy. Brachytherapy definitively localizes the radiation dose to the region to be treated and ensures that the dose is delivered at a high rate. However, brachytherapy is difficult to control as far as a treatment plan (e.g., the surgeon can hold the probe in a variety of positions for any given patient) and the brachytherapy source typically cannot be turned off (e.g., strontium has a 29 year half-life). Radiotherapy System The Portable Orthovoltage Radiotherapy Treatment system (PORT) 10 in FIG. 1A can be configured to deliver anywhere from about 1 Gy to about 40 Gy or from about 10 Gy to about 20 Gy to regions of the eye including the retina, sclera, macula, optic nerve, the capsular bag of the crystalline or artificial lens, ciliary muscles, lens, cornea, canal of schlemm, choroid, conjunctiva, etc. In some embodiments, the system can be configured to deliver from about 15 Gy to about 25 Gy. In some embodiments, the system 10 is capable of delivering x-ray therapy in any fractionation scheme (e.g. 5 Gy per day or 10 Gy per month or 25 Gy per year) as the treatment planning system can recall which regions had been treated based on the unique patient anatomical and disease features. These features and previous treatments are stored in the treatment database for future reference. The system can also deliver different photon energies depending on the degree of disease or the region of the eye being treated. For example, the x-ray generation tube can deliver from about 20 KeV photons to about 40 KeV photons or to about 60 KeV photons, or to about 100 KeV photons. It may be desirable to use about 20 KeV to about 50 KeV photons for structures in the anterior portion of the eye because these energies will penetrate less whereas it may be desirable to utilize from about 60 KeV to about 100 KeV photons or greater for structures in the posterior region of the eye for greater penetration to the retina. In some embodiments, the x-ray generation tube can deliver photons with photon energies from about 10 keV to about 500 keV, from about 25 keV to about 100 keV, from about 25 keV to about 150 keV, and/or from about 40 keV to about 100 keV. In some embodiments, selection of the photon energy can be based on diagnostic calculations, which can include a model of the eye created from anatomic data taken from the actual eye. Although generally specific for the eye in this disclosure, PORT can be applied to any superficial body structure within reach of orthovoltage x-rays or to structures accessible during surgical procedures. For example, in regions such as the breast, it may be desirable to use x-rays with energies greater than about 40 keV but less than about 200 keV to reach the structures of interest. Other structures of interest include, for example, skin lesions, facial lesions, mucosal lesions of the head and neck, nails, muscles, soft tissues, anorectal regions, prostate, genital regions, joints, tendons, muscles, and the urogenital tract. PORT can be applied to specific structures within the eye while sparing others because of its imaging systems, its modeling systems, and its finely-tunable collimators can provide precisely directed x-ray beams that can be targeted on specific structures within the eye with small penumbras (for example, 1-5 mm beams with less than 10% penumbra). PORT therapy is also based on individualized, biometric representations of the eye which allows a personalized treatment plan to be created for every patient. As described above, orthovoltage generators, or other low energy x-ray generators, allow for the system to be placed in a room without requiring thick protective walls or other special shielding apparatus or special controls which would be prudent with devices generating x-rays with photon energies greater than about 500 keV. Orthovoltage generators, or other low energy x-ray generators, are also more compact than linear accelerators which allow them to be moved and directed with less energy from control motors as well as with less internal and external shielding. The lower energy x-ray generators also allow for simpler collimation and beam directing schemes with small penumbras and tight collimation. In addition, in a scheme where it is desired to move the x-ray source, much less energy is used to move the source to different positions, and the entire system is scaled down in size with lower energy x-ray sources. In some embodiments, the radiotherapy system is used to treat a wide variety of medical conditions relating to the eye. For example, the system may be used alone or in combination with other treatments to treat macular degeneration, diabetic retinopathy, inflammatory retinopathies, infectious retinopathies, tumors in the eye or around the eye, glaucoma, refractive disorders, cataracts, post-surgical inflammation of any of the structures of the eye (e.g., trabeculoplasty, trabeculectomy, intraocular lenses, glaucoma drainage tubes, corneal transplants, infections, idiopathic inflammatory disorders, etc.), ptyrigium, dry eye, and other ocular diseases or other medical conditions relating to the eye. The radiotherapy treatment system preferably includes a source, a system to control and move the source, an imaging system, and an interface for a health care professional to input treatment parameters. Specifically, some embodiments of the radiotherapy system include a radiotherapy generation module or subsystem that includes the radiation source and the power supplies to operate the source, an electromotive control module or subsystem which operates to control the power to the source as well as the directionality of the source, a coupling module which links the source and control to the structures of interest (e.g., the eye), and an imaging subsystem; these modules are linked to an interface for a healthcare professional and form the underpinnings of the treatment planning system. The terms “module” and “subsystems” can be used interchangeably in this disclosure. FIG. 1A illustrates a side view of embodiments of a system 10 for treating ocular diseases using radiotherapy. In the embodiments illustrated, the radiotherapy treatment system 10 comprises a radiotherapy generation module or subsystem 110, a radiotherapy control module or subsystem 120, an interface display 130, a processing module 140, a power supply 150, a head restraint 160, and an imaging module with a camera 400. In some embodiments, the radiotherapy device delivers x-rays to the eye 210 of a patient 220. The power supply 150 preferably resides inside the system 10 or adjacent the system 10 (e.g., on the floor). In some embodiments, however, the power supply 150 can reside in a different location positioned away from the system 10. The power supply 150 can be physically coupled to the x-ray generator 110 (in a monoblock configuration) or can be uncoupled from the x-ray generator (e.g., the x-ray source moves independently of the power supply and is connected through high power cables). In some embodiments, a cooling system for the X-ray tube is also provided. The cooling system can be water or oil or air convection and can be attached or located a distance from the radiotherapy system 10. Voltage can be wall voltage of about 110V or 220V (with assistance of a transformer) which can be used for the devices in the system shown in FIG. 1A. Currents to drive x-rays out of the device may be on the order of 1 amp or lower down to about 50 mA or even about 5-10 mA. What is desired of the power supply is that a high voltage be generated to drive the electrons from the cathode in the x-ray tube to the anode of the x-ray; electron movement is performed within a vacuum inside the x-ray tube. The high voltage (e.g., about 30,000-300,000 volts or higher) may be desired to accelerate the electrons inside the vacuum. A second current is typically used with x-ray power supplies in order to generate the electrons from a filament, the electrons are subsequently accelerated through the voltage potential. Therefore, x-ray power supplies typically have two power supplies in order to generate x-rays. Once generated, the electrons speed toward the anode under the influence of the high voltage potential; the anode is where the x-ray generating material typically rests (e.g., tungsten, molybdenum). Once the electrons strike the x-ray generating material target, x-rays are generated. An absorbing metal (e.g., aluminum, lead, or tungsten) within the casing of the system of FIG. 1A will absorb much of the generated x-rays which have been scattered from the source 110. The x-rays, which are pre-planned to escape, are emitted from the source and travel into a collimator (e.g., a primary or secondary collimator) and optionally through a filter (e.g. an aluminum filter). The collimator is intended to direct the x-rays toward the patient 220. Notably, as described herein, collimators can be designed and manufactured so as to minimize penumbra formation and scatter and to optimize the shape and/or direction of the x-ray beam. The power supply is preferably connected to the x-ray source by a high power cable that is highly insulated to prevent power leakage. The collimator can be one or more collimators (e.g., a primary 1030 and a secondary collimator 1040, and even a third collimator 1052, as illustrated in FIG. 2A). In some embodiments, a secondary (shaping) collimator is placed close to the eye 1300 (e.g., within 10 cm) of the patient, and the primary collimator 1030 is placed close to the source 1070. This type of configuration can decrease the penumbra generated by the source 1070 on the ocular structures 1300. In some embodiments, collimators are specialized apertures. The apertures can be adjustable; for example, the aperture can be adjustable from about 1.0 cm to about 0.5 mm or below 0.5 cm to about 0.01 cm. In some embodiments, the aperture is adjustable (e.g., automatically or manually by the operator of the machine) between about 0.5 mm and about 7.0 mm. In some embodiments, the collimator is constructed from tungsten, lead, aluminum, or another heavy metal. In some embodiments, the collimator has a cylindrical shape for the radiation to pass through; in other embodiments, the collimator has a coned shape for the radiation to pass through. In some embodiments, the collimator aperture has a rounded shape. In certain embodiments, the collimator has a curvilinear shape for the x-ray to pass through. In some embodiments, the collimator is cut using wire-EDM; in other embodiments, the collimator path is cut and polished using a laser. The smooth contour of the collimator allows for minimal scattering as the radiation passes through the collimation apparatus. In some embodiments, the collimator has a region of thinner metal than another region so that the beam is relatively modified but does not have a sharp contour. In some embodiments (FIG. 2C), a light pointer 1410 (e.g., a laser beam emitted from a source 1450) is coupled to a collimator 1405, or behind the collimator 1405, so that the light pointer 1410 is coincident with an x-ray beam 1400; the light pointer 1410 can indicate the position on a surface of an eye 1300 through which the radiation source enters by tracking angles of incidence 1420, 1430 of the collimator and x-ray beam. The collimator 1405 is preferably co-linear with the light source 1450 which can act as a pointer to indicate the point on the eye through which the radiation enters the eye 1300. In some embodiments, a laser pointer 1210, illustrated in FIG. 2B′ sits on top of, or is coincident with the x-ray beam through the primary or secondary collimator 1215. The laser pointer 1210 can be reflected off a reflector 1220 that aligns the laser pointer 1210 with the collimator opening 1216 such that the laser point 1210 strikes substantially the same position of a surface beyond the collimator opening as does the x-ray 1200. The reflector 1220 can be a beam splitter, and the beam splitter can be transparent to x-ray energy 1200. The laser pointer 1210 can emit a wavelength that is detectable by the system camera 1460. Because the pointer is seen on the camera, the pointer indicates where the radiation beam enters the eye. The pointer 1410 can also serve as a visual verification that the x-ray source is powered on and directed in the proper orientation with respect to the ocular structure, or target tissue 1480, of interest. With a second camera in the system, the angle of incidence of the laser pointer and the x-ray beam can be determined. At least one camera 400, 1460 is included in the system to at least track the eye in real time. In some embodiments, the camera 400, 1460 images the eye with or without the x-ray source tracking device (e.g., laser pointer) described above. The camera can detect the position of the eye and relate the direction of the x-ray and collimator system to the position of the eye. An optional display 130 directed to the operator of the radiotherapy system on the system 10 can depict the position of the x-ray device in real time in some embodiments. In another embodiment (FIG. 4), the camera 2055 detects the position of the eye and digitizing software is used to track the position of the eye. The eye is meant to remain within a preset position 2060; when the eye deviates from the position 2060 beyond a movement threshold, a signal 2090 can be sent to the radiation source 2000. As used herein, the term “movement threshold” is intended to have its ordinary meaning, which includes, without limitation, a degree or measurement that the eye is able to move and still be within the parameters of treatment without shutting the radiation source 2000 off. In some embodiments, the movement threshold can be measured in radians, degrees, millimeters, inches, etc. The radiation source 2000 is turned off when the eye is out of position 2057 beyond the movement threshold, and the radiation source is turned on when the eye is in position 2054, or within the movement threshold. In some embodiments, a connection, or coupling, 162 extends from the system and contacts the eye 210 (FIGS. 1D-1E). The connection can be a physical connection which can include an optical or other communication between the system and the eye in addition to a mechanical connection. The physical connection 162 can serve several functions. For example, in some embodiments, the connection 162 is a mechanical extension which allows the position of the eye to be determined because it is directly applied to the cornea or sclera. It also provides for inhibition of the eye so that the patient is more inclined to be compliant with keeping their eye in one position throughout the treatment. In addition, the eye can be moved into a pre-determined position, in the case, for example, when the patient's eye has been paralyzed to perform the procedure. Finally, the physical contact with the eye can be used to protect the corneal region using an ophthalmic lubricant underneath the physical contact device. The physical connection 162 from the cornea allows for positioning of the eye with respect to the system. The physical connection 162 to the eye from the radiotherapy system 10 can contact the limbus 910 (also see FIG. 1C 308) around the eye or can contact the cornea 920 or the sclera 930. The physical connection can contain a suction type device 912 which applies some friction to the eye in order to move the eye or hold the eye in place with some force. In certain embodiments, the connection 162 contacts the sclera when suction is applied. The physical connection 162 can dock onto a scleral lens 940 or a corneal lens which is inserted separately into or onto the eye; piece 160 then docks into or onto the scleral or corneal contact lens. Any of the materials of the physical connection can be transparent to x-rays or can absorb some degree of x-ray. The physical connection 162 can help to stabilize the eye of the patient, preventing eye movement underneath the lens. If a lubricant is inserted inside the lens, the lens can hold a gel or lubricant to protect the eye during the procedure. The lens can also contain through holes which can provide the cornea with oxygen. The physical connection 162 can be movable with respect to the remainder of the radiotherapy system; the physical connection 162 can be rigid, substantially rigid, or can contain a spring 165, which allows flexibility in the axial or torsional direction. In some embodiments, the connection 162 is not mechanical at all but is an optical or other non-contact method of communicating between a radiotherapy system and a lens 940 positioned on the eye. The physical connection 162 can signify the coordinate reference frame for the radiotherapy system and/or can signal the movement of the device with respect to the eye. Connection 162 can therefore assist in maintaining eye location in addition to maintaining eye position by inhibiting movement of the patient. Physical connection 162 can contain radiotransmitters or features which can be captured on a camera so that the eye can be located in three-dimensional space. In some embodiments, the physical connection 162 to the eye is docked into position on the eye by the physician so that it identifies the center of the limbus and the treatment axis through its center. The position of the eye can then be identified and tracked using by the radiotherapy system. With knowledge of the center of the limbus in combination with the eye model, the radiotherapy system can then be directed about the treatment axis and center of the limbus to deliver radiation to the retina. X-ray source 110 can travel around a central axis 405 or a focal point within the eye 210, such as, for example, illustrated in FIG. 1D by arrows 112. Alternatively, the x-ray source 110 can travel around a floating focal point as defined by the treatment planning system and virtual model of the eye. A floating focal point is one anywhere in the eye as opposed to a fixed focal point such as the macula for example. In some embodiments, the x-ray source can move with six degrees of freedom around a fixed or moving axis. In some embodiments, the x-ray source remains fixed in one spot to treat an eye structure in the anterior portion of the eye or even the posterior portion of the eye depending on how large an area is to be treated and the dose required. In some embodiments, the x-ray source 110 focuses x-rays on a target by moving to different positions around the eye and delivering x-rays through the sclera at substantially different entry points on the sclera but each x-ray beam reaching a substantially similar target within the eye. In some embodiments, the x-ray source remains in one location, delivering x-ray energy to and through the sclera and to regions within the eye, such as the retina and specifically the macula. In some embodiments, the x-ray source 110 is moved with five degrees of freedom, four degrees of freedom, three degrees of freedom, or two degrees of freedom. In some embodiments, the x-ray source 110 is stationary and the collimator is moved or the eye or the patient is moved to project the beam to different regions of the eye. In some embodiments, the retina is treated by maintaining the x-ray beam in one position with respect to the sclera. The x-ray source 110 can be moved automatically by a robotic arm or manually by the operator of the system. The ultimate three-dimensional position of the x-ray source 110 can be dictated by the treatment plan which communicates between a model of the eye and with the robotic arm to determine the position of the x-ray beam relative to the eye. In some embodiments, only a small amount of movement is required of the x-ray source to entirely treat a disease of the retina, such as macular degeneration and/or diabetic macular edema. In these embodiments, six degrees of freedom can be applied to the x-ray source 110, but the range of each degree of freedom is preferably limited so that the movement system only travels within a volume of about 1000 cm3, 500 cm3, 100 cm3, or about 50 cm3. The speed of the robot within these volumes can be defined such that the robot moves 0.5 cm/s, 1 cm/s, 3 cm/s, 5 cm/s. Because each fractional treatment dose is relatively short and applied over a small distance, the robot can sacrifice speed and travel distance for smaller size. In some embodiments, it is a goal of the treatment system to deliver radiation therapy substantially through the pars plana region of the eye (see FIG. 1C). Pars plana 215 is the region of the eye between the pars plicata 218 and a peripheral portion of the retina 280, the ora serrata. The pars plana 215 region of the eye contains the fewest critical structures enroute from the sclera 260 to the retina 280. It is typically the region through which surgeons will inject pharmaceuticals in order to inject drugs into the eye or to perform vitrectomies because the smallest risk of damage to ocular structures exists with this approach Likewise, radiotherapy can be delivered to the posterior region of the eye through the pars plana region 215 to minimize the potential for damage to structures such as the lens, yet reaching regions such as the fovea 240 and with minimal radiation reaching the optic nerve 275. The image-guided orthovoltage therapy described herein allows such specific treatment. The central axis 300 of the eye is typically defined by the geometric axis 300, but in some embodiments, it can be defined by the visual axis 305; the visual axis of the eye is represented by a line 306 from the center of the fovea 305 through the center of the pupil. The geometric axis 300 can be defined by a perpendicular straight line 300 from the center of the limbus 308 straight directly back to the retina; this axis can also be referred to as the treatment axis. The limbus 308 is technically the point where the cornea meets the sclera or visually the point where the pigmented region of the eye meets the white region of the eye. The pars plana angle 212 can be measured from the geometric central axis 300 and can range from about 10 degrees to about 50 degrees off the central geometric axis 300. The visual axis 306 is the straight line from the center of the macula 240 and out the front of the eye through the center of the pupil 217. The pars plana 215 region of the eye can be related to the central axis 300 of the eye through an angle α 212. In some embodiments, x-rays with a tight collimation (e.g., smaller than about 6-8 mm in diameter) and a small penumbra (e.g., less than about ten percent at the sclera) enter the pars plana region 215 of the eye, avoiding some of the critical structures of the eye, to reach structures which are to be treated, such as the retina. In some embodiments, during the treatment, the eye can be stabilized with the assistance of physical or mechanical restraint or by patient fixation on a point so that the x-rays enter the eye substantially only in the pars plana region 215. In certain embodiments, the patient is stabilized with respect to the axis of the eye. If the patient or device moves, then the camera detects the movement and turns the device off or closes a shutter over the region the x-rays leave the device or the collimator. In some embodiments, the x-ray source 110 is moved about the eye to one or more positions determined by a treatment planning system, delivering radiation through the pars plana region 215 of the eye to reach the retina. The total dose is divided across different regions of the sclera but penetrates through the pars plana 215 region to reach the desired region of the retina (for example, the macula or the fovea). The head restraint 160 portion of the radiotherapy system 10 may be used for restraining the head of the patient 220 so as to substantially stabilize the location of the patient's eye 210 relative to the radiotherapy treatment system 10. The physician applying the treatment can align the central axis 300 of the patient's eye with the x-ray source. The restraint 160 can maintain the patient's position during the treatment. If the patient moves away from the restraint 160 or moves their eyes from the restraint, then the x-ray machine can be turned off (gating) manually or automatically and the patient's position readjusted. In general terms, the patient's head is maintained in position with the head restraint 160 while the eye 210 is tracked by the imaging system 400 and/or treatment planning system and the x-ray source 110 is moved so that the x-ray beam enters the eye through the pars plana region 215; the x-rays, therefore, penetrate to the target regions of the retina and create minimal damage on their way to the retina. The treatment planning system 800 (FIGS. 1B and 2E) provides the physician interface with the system 10. The treatment plan is developed based on pre-treatment planning using a combination of biometric modalities including an imaging subsystem that can include, for example, OCT, or optical coherence tomography, CT scans, MRI scans, and/or ultrasound modalities. The information from these modalities are integrated into a computer-generated virtual model of the eye which includes the patient's individual anatomic parameters (biometry) as well as the individual's specific disease burden. The treatment plan is output, for example, on the interface display 130 module of the radiotherapy system 10. The physician can then use the virtual model in the treatment plan to direct the radiation therapy to the disease using the radiotherapy system 10. As used herein, “eye model” or “model of the eye” refers to any representation of an eye based on data, such as, without limitation, an anteroposterior dimension, a lateral dimension, a translimbal distance, the limbal-limbal distance, the distance from the cornea to the lens, the distance from the cornea to the retina, a viscosity of certain eye structures, a thickness of a sclera, a thickness of a cornea, a thickness of a lens, the position of the optic nerve relative to the treatment axis, the visual axis, the macula, the fovea, a neovascular membrane, and/or an optic nerve dimension. Such data can be acquired through, for example, imaging techniques, such as ultrasound, scanning laser ophthalmoscopy, optical coherence tomography, other optical imaging, imaging with a phosphor, imaging in combination with a laser pointer for scale, and/or T2, T1, or functional magnetic resonance imaging. Such data can also be acquired through keratometry, refractive measurements, retinal nerve-fiber layer measurements, corneal topography, etc. The data used to produce an eye model may be processed and/or displayed using a computer. As used herein, the term “modeling” includes, without limitation, creating a model. FIG. 1B depicts a schematic overview of the x-ray treatment system 10. For conceptual simplicity, the components of the system are depicted in the four boxes. The overall treatment planning system 800 is depicted by the background oval shape, depicting a global interconnect between the subsystems. The treatment planning system 800 directs the four subsystems toward treatment of the region indicated by the physician. The four subsystems in general terms include an x-ray subsystem 700, a coupling subsystem 500, an electromotive subsystem 600, and an imaging subsystem 400. These subsystems or modules interact to provide an integrated treatment to the eye of a patient. The subsystems work together to coordinate the treatment planning system 800. The treatment planning system (TPS) 800 also provides the interface between the physical world of the eye, the physical components of the system, and a virtual computer environment which interacts with the physician and treatment team and contains the specific patient and disease information. The coupling system 500, primarily, and the imaging system 400, secondarily, help link the physical world and the virtual world. The virtual world contains a computer-generated virtual model of the patient's eye 505 based on physical and biometric measurements taken by a health practitioner or the imaging system 400 itself. The computer model 505 (FIG. 2D) in the virtual world further has the ability to simulate the projection 510 of an x-ray beam 520 from a radiation source 524 through an anterior region of the eye 515 to the structure 514 to be treated on or in the eye 514 based on different angles of entry into the eye. The model can also include important eye structures, such as the optic nerve 512, to consider during the treatment planning process. The virtual world also contains the physician interface to control the device 524 and interface the device with respect to the physical world, or that of the actual physically targeted structure. After integrating the inputs from the physician and modeling the beam angles and desired direction to direct the therapy, the virtual world outputs the information to the electromotive subsystem to move the x-ray device to the appropriate position in three-dimensional space. The coupling subsystem 500 (in the physical world) can include a mechanism to determine the angle of incidence of the x-ray beam with respect to the surface of the eye using one or more laser or angle detectors, as discussed above. In some embodiments, the coupling system 500 contains a camera 518 which can image a spot 516 on or in an eye. Information from the camera is then preferably transferred to the virtual eye model 522 and again to the motion and radiotherapy system 524. In certain embodiments, the coupling system 500 is a physical connection with the eye. In some embodiments, the coupling system 500 is not a physical link but is a communication link between a lens on the eye and a detection system. For example, a lens can be a communication beacon to relay eye position to the system 500. In some embodiments, the lens can contain markers that are imaged by the imaging camera 518, through which the next stage in the therapy can be determined. In some embodiments, a combination of these techniques is used. In some embodiments, the position of the eye and the x-ray source are known at all times, and the angles of entry of the x-ray can therefore be realized. For example, the central axis of the eye can be determined and the x-ray source offset a known angle from the central axis. The central axis, or treatment axis, in some embodiments can be assumed to be the axis which is perpendicular to the center of the cornea or limbus and extends directly posterior to the retina, as discussed previously. Alternatively, the coupling subsystem can detect the “glint” or reflection from the cornea. The relationship between the glint and the center of the pupil is constant if the patient or the patient's eye is not moving. If the patient moves, then the glint relative to the center of the pupil is not in the same place. A detector can detect when this occurs, and a signal can be sent from the virtual world to the x-ray device to turn the x-ray device off or to shutter the system off. The actual acquisition method notwithstanding, the information obtained from the coupling subsystem is preferably sent to the computer system and to the virtual eye model. The imaging subsystem 400 captures an image of the eye in real time with a camera 1460 and feeds the data into the software program that creates a virtual model of the eye. In combination with the physical world coupling system 500, the predicted path of the x-ray beam through the eye can be created on the virtual image. Depending on the region to be treated, the electromotive system and/or x-ray system can be readjusted; for example, a robot arm can move the x-ray source 110 to a position to send a radiation or x-ray beam to a location on or in the eye based on the model of the eye as created by the TPS and as captured by the imaging system 400. In certain embodiments, the radiotherapy generation system 100 can include an orthovoltage (or low energy) radiotherapy generator as the x-ray subsystem 700, as discussed in further detail with reference to FIG. 1A, a schematic of the device. The radiotherapy generation subsystem 110 generates radiotherapy beams that are directed toward the eye 210 of the patient 220 in FIG. 1A. In certain embodiments, the radiotherapy control module 120 includes an emitter 200 that emits a directed, narrow radiotherapy beam generated by the radiotherapy generation subsystem 110. As used herein, the term “emitter” is intended to have its plain and ordinary meaning, and the emitter can include various structures, which can include, without limitation, a collimator. In some embodiments, the control module 120 is configured to collimate the x-ray beams as they are emitted from the radiotherapy generation subsystem 110. The x-ray subsystem 700 can direct and/or filter radiotherapy rays emitted by the x-ray tube so that only those x-rays above a specific energy pass through the filter. In certain embodiments, the x-ray subsystem 700 can include a collimator through which the pattern or shape of an x-ray beam is determined. The filtering of the source preferably determines the amount of low energy inside the x-ray beams as well as the surface-depth dose as described in ensuing figures. In some embodiments, it is desirable to deliver orthovoltage x-rays with a surface-to-depth dose less than about 4:1 to limit dose accumulation at the surface of the eye. In some embodiments, it is desirable to have a surface-to-depth dose less than about 3:1 or 1.5:1 but greater than about 1:1 when using orthovoltage x-rays. Therefore, the radiotherapy control system can control one or more of the power output of the x-ray, the spectrum of the x-ray, the size of the beam of the x-ray, and the penumbra of the x-ray beam. In certain embodiments, the electromotive subsystem 600 of the radiotherapy system may move the x-ray source and the collimator to direct a narrow radiotherapy beam emitted from the x-ray source to irradiate specific regions of the patient's eye 210 by directing energy onto or into targeted portions of the eye 210, while at the same time avoiding irradiation of other portions of the eye 210. For example, the system 10 may target a structure of the posterior region of the eye, such as the retina, or a structure on the anterior region of the eye, such as the trabecular meshwork, the sclera, the cornea, the ciliary processes, the lens, the lens capsule, or the canal of schlemm. The system 10 can deliver radiotherapy to any region of the eye, including, but not limited to, the retina, the sclera, the macula, the optic nerve, the ciliary bodies, the lens, the cornea, Schlemm's canal, the choroids, the capsular bag of the lens, and the conjunctiva. In certain embodiments, the x-ray subsystem 700 can collimate the x-ray to produce a narrow beam of specified diameter and shape. For example, in certain embodiments using a collimator, the diameter of the collimator outlet may be increased or decreased to adjust the diameter of the radiotherapy beam emitted by the collimator. In certain embodiments, the x-ray subsystem 700 can emit a beam with a diameter of about 0.1 mm to about 6 mm. In certain embodiments, the x-ray subsystem 700 can emit a beam with a diameter of less than about 0.1 mm. In certain embodiments, the x-ray subsystem 700 can emit a beam with a diameter of between about 0.5 mm and about 5 mm. As described in further detail below, narrow beams and virtual models are useful to ensure that the energy is applied to a specific area of the eye and not to other areas of the eye. In some embodiments (FIG. 2B′-2B″″), the radiation control module can emit an x-ray beam with a circular 1212 or non-circular 1214 shape; in some embodiments, the radiation control module can emit an x-ray beam with a rectangular shape 1214 or a square shape. In some embodiments, the radiation control module can emit an x-ray beam with an arc shape or an elliptical shape or a doughnut configuration 1217 through a circular collimator 1215 with an opaque region 1218 in the center. In some embodiment, the collimator 1215 can include a conical-shaped opening 1232, such as depicted in FIG. 2B″″, for providing a precisely shaped beam 1200. In certain embodiments, the radiotherapy system 10 allows for selective irradiation of certain regions of the eye without subjecting other areas of the eye to radiation by using a narrow, directed treatment beam, the treatment beam dictated by the specific anatomy of the patient's eye. For example, the radiotherapy control module 120 can direct radiotherapy beams generated by the radiotherapy generation module 110 to a patient's macula, while substantially avoiding radiation exposure to other portions of the patient's eye, such as the lens, the trabecular apparatus, and the optic nerve. By selectively targeting specific regions of the eye with radiation based on knowledge of the anatomy of the eye and linking the radiation system to the anatomy for treatment purposes, areas outside of the treatment region may avoid potentially toxic exposure to radiation. In some embodiments, the x-ray beam follows a trajectory 250 that enters the eye through the pars plana region 215 which is a zone of the sclera 260 between the iris 270 and the retina 260. By directing the beam to this region and limiting the penumbra or scatter of the beam using specialized collimators, the beam can be localized onto an eye structure with minimal photon delivery to other structures of the eye, such as the cornea 255, the ciliary body and fibers 216 and other structures. In certain embodiments, the radiotherapy treatment system 10 can include a shutter for controlling the emission of radiotherapy beams. The shutter may comprise a material opaque to the radiation generated by the radiation generation module 110. In certain embodiments, a shutter may be used to control the emission of beams from the radiotherapy generation module 110. In certain embodiments, a shutter may be used to control the emission of beams from the radiotherapy control module 120. In certain embodiments, the shutter may be internal to either of said modules 110 and 120, while in certain embodiments, the shutter may be external to either of said modules 110 and 120. In some embodiments, the system 10 is turned off to stop x-ray delivery, and in certain embodiments, the x-ray source 110 is turned off or its intensity turned down to limit or stop x-ray delivery to the target. In certain embodiments, the shutter or aperture changes shape or size. In certain embodiments, and as explained above with respect to FIG. 1A, the radiotherapy treatment system 10 can deliver radiotherapy beams from one angle. In certain embodiments, the radiotherapy treatment system 10 can deliver radiotherapy beams from more than one angle to focus the beams on the treatment target. Certain embodiments of the system 10 that can deliver radiotherapy beams from more than one angle can include a plurality of stationary radiotherapy directing modules. The stationary radiotherapy modules can be positioned in a wide variety of locations to deliver radiotherapy beams to the eye at an appropriate angle. For example, certain embodiments of the radiotherapy treatment system 10 include five radiation source module-radiation directing module pairs that are connected to the radiotherapy treatment system 10 in such a way that they are spaced equidistantly around a circumference of an imaginary circle. In this embodiment, the power supply could be a switching power supply which alternates between the various x-ray generators. Certain embodiments of the system 10 that can deliver radiotherapy beams from more than one angle can include moving the radiotherapy directing module. Certain embodiments of the system 10 that can deliver radiotherapy beams from more than one angle can include moving the radiotherapy source using an electromotive subsystem 700 (FIG. 1B), such as a robot. In some embodiments of the present disclosure, orthovoltage x-rays are generated from the x-ray generation module 700. X-ray photons in this orthovoltage regime are generally low energy photons such that little shielding or other protective mechanisms can be utilized for the system 10. For example, diagnostic x-rays machines emit photons with orthovoltage energies and require minimal shielding; typically, only a lead screen is used. Importantly, special rooms or “vaults” are not required when energies in the orthovoltage regime are used. Diagnostic x-ray machines are also portable, being transferable to different rooms or places in the clinical environment. In contrast, linear accelerators or LINACS which typically deliver x-rays with energies in the MeV range require thickened walls around the device because higher energy x-ray photons have high penetration ability. Concomitant with the higher energy photons, LINACS require much greater power and machinery to generate these high energy photons including high voltage power supplies, heat transfer methodologies, and internal shielding and protection mechanisms. This increased complexity not only leads to higher cost per high energy photon generated but leads to a much heavier device which is correspondingly more difficult to move. Importantly, as described above and demonstrated experimentally below, MeV photons are not necessary to treat superficial structures within the body and in fact have many disadvantages for superficial structures, such as penetration through the bone into the brain when only superficial radiation is required. X-Ray Subsystem The x-ray subsystem 700 generates x-rays and can include a power supply, a collimator, and an x-ray tube. In certain preferred embodiments, the x-ray subsystem 700 includes an orthovoltage x-ray generation system 1070 to produce orthovoltage x-rays with energies between 10 KeV and 500 KeV or even up to 800 KeV. This type of x-ray generation scheme is well known in the art and includes a high voltage power supply which accelerates electrons against a tungsten or other heavy metal target, the resulting collision then generating electromagnetic energy with x-ray energies. Orthovoltage or low energy x-ray generators typically emit x-rays in the range from about 1 KeV to about 500 KeV or even up to about 1 MeV. In some embodiments, the system described herein emits x-rays with photon energies in the range from about 25 KeV to about 100 KeV. The use of low energy x-ray systems allow for placement of these x-ray treatment systems in outpatient centers or other centers and will not require the overhead and capital requirements that high energy (MeV or gamma) x-ray systems require. In the treatment of ophthalmologic disorders, such as AMD, placement in the ophthalmologist office or close to the ophthalmologic office is important because the ophthalmologists can treat many more patients, a very important component when treating a disease that afflicts millions of patients. If the device were limited to operating within vaults inside radiation oncology centers, the number of treatable patients would be much more limited because of access, cost, competition with other diseases, and other logistics. The radiation generation module in some embodiments is composed of components that are arranged to generate x-rays. For example, a power supply generates current which is adapted to generate and accelerate electrons toward an anode, typically manufactured from a heavy metal such as tungsten, molybdenum, iron, copper, nickel, or lead. When the electrons hit one of these metals, x-rays are generated. An exemplary set of x-ray spectra is shown in FIG. 1F. KVp refers to the maximum wavelength of the x-ray generated. For example, the 80 KVp spectra in FIG. 1F has a maximum of 80 KeV with a leftward tail of lower energy radiation. Similarly, the 60 KVp spectrum has a maximum of 60 KeV with a similar leftward tail. All spectra in the figure have been filtered through 3 mm of Aluminum for filtering which shapes the spectral curve as lower wavelengths are filtered to a greater degree than the higher wavelengths. A power supply 150 as shown in FIG. 1A powers the radiation module. The power supply 150 is rated to deliver the required x-ray with a given current. For example, if 80 KeVp x-rays are being delivered from the source at 10 mA, then the power required is 800 W (80 kilovolts×0.01 A). Connecting the power supply to the x-ray source is a high voltage cable which protects and shields the environment from the high voltage. The cable is flexible and in some embodiments has the ability to be mobile with respect to the power supply. In some embodiments, the power supply is cooled with an oil or water jacket and/or convective cooling through fins or a fan. The cooling fluid can move through the device and be cooled via reservoir outside the system 10. Electromotive Subsystem FIG. 2A depicts embodiments of the electromotive subsystem 600 of the treatment system illustrated in FIG. 1B. The subsystem is an advantageous component of the therapeutic system because it controls the direction and the size of the x-ray beam. In general terms, the electromotive subsystem is directed in the space of the global coordinate system 1150 by the personalized eye model created from the patient's biometric data. The data from the model is transferred through the treatment planning system (TPS) to the electromotive subsystem 600 to direct the x-ray beam to the target on or in the eye. In certain embodiments, the system can include a collimation system, a shutter system, and an electromechanical actuation system to move the x-ray source and/or collimators. Referring to FIG. 2A, orthovoltage x-ray source 1070 is depicted. Collimators 1030, 1040, and/or 1052 are calibrated to produce a small collimated beam 1062 of x-ray photons; in a preferred ophthalmic embodiment, the tightly collimated beam 1062 has an area of from about 1 mm2 to about 20 mm2 in a circular or other shape and a diameter of from about 0.5 mm to about 6.0 mm. Multiple collimators allow for improved penumbra percentages; the smaller the penumbra, the finer the application of x-rays to a specified structure. FIGS. 2B′-2B″″ depicts embodiments of collimator designs in which a variety of collimator configurations are depicted. For example, FIG. 2B″″ depicts a collimator configuration in which a doughnut shape of x-rays is generated; FIG. 2B″″ depicts a collimator configured with a nozzle, or conical, shape 1232 to limit the penumbra or create a substantially uniform radiation beam. The collimators, operating in conjunction with filters 1010, 1020 preferably cause the x-rays to leave the collimator in a beam 1090 having a substantially parallel configuration. The electromotive subsystem 1100 interacts with and is under the direction of the global treatment planning system 800 in FIG. 1B. The electromotive subsystem 1100 receives commands from the treatment planning system 800 which can dictate among other things, the length of time the x-ray machine is turned on, the direction of the x-ray beam with respect to the eye target using data from the eye model or treatment planning system, the collimator size, and the treatment dose. The eye target 1300 and the control system 1100 can be linked in global coordinate space 1150 which is the basis of the coupling system. The treatment planning system 800 directs the therapy using global coordinate system 1150. The x-ray control system 1100 dictates the direction and position of the x-ray beam with respect to the ocular target and moves the x-ray source into the desired position as a result of commands from the treatment planning system 800. In some embodiments, the collimators and/or the x-ray source can be placed on a moving wheel or shaft (1100, 1110, 1120) with one or more manual or automated degrees of freedom allowing the beam to be moved to a multitude of positions about the globe of the eye. In some embodiments, the x-ray source is movable with greater than one degree of freedom such as with a robot or automated positioning system. The robot moves the x-ray source with respect to a global coordinate system such as a cartesian coordinate system 1150 or a polar coordinate system. The origin of the coordinate system can be anywhere in physical space which is convenient. In some embodiments, the x-ray source is movable with four, five, or six degrees of freedom. In some embodiments, a robot is also utilized to move any of the other components of the x-ray control system such as the collimators. In some embodiments, the collimators are controlled with their own electromechanical system. The electromotive subsystem can also contain one or more shutters to turn the beam on and/or off in an instant if desired (for example, if the patient were to move away). The x-ray source 1070 and/or collimators can move in any axis in space through an electromechanical actuation system (1100, 1110, 1120). In this embodiment, the treatment planning system can and then turning the device off when the eye is moved outside the target area. The x-ray coupling subsystem 500 integrates with the x-ray generation subsystem 700 under the umbrella of the treatment planning system 800. Also depicted in FIG. 2A and in more detail in FIG. 2C is at least one laser pointer 1060 (1410 in FIG. 2C) which can serve multiple purposes as described. In some embodiments, the laser pointers 1060 couple with the direction of the collimated x-ray beam 1090 so that the centroid of the laser beam is approximately identical to the centroid of the x-ray beam 1090 so as to have a visible marker as to where the x-ray beam is being delivered. Because x-rays are not visible, the laser pointers serve to identify the direction of the x-ray beam relative to other parts of the radiotherapy system. Where the center of the x-ray beam is pointed, the center of the laser beam is correspondingly pointed as well as shown in FIG. 2C. Radiotherapy Coupling Subsystem A third major subsystem of the present disclosure is the coupling subsystem or module 500. In general terms, the coupling module 500 coordinates the direction of the x-ray beam position to the position of the eye. As depicted in FIGS. 2A-2D, embodiments includes laser pointer 1060 (one or more may be desired) that follows the direction of the x-ray beam. In some embodiments, the laser pointer(s) allow for detection of the angles of incidence of the laser beam 1500 (FIG. 3) with respect to the sclera or other surface they impinge upon. The angles of incidence 1510, 1520 can be defined by two orthogonal entrance angles (θ, φ) on the sclera or other surface. The centroids of the one or more laser pointers 1070 coincide with the centroid of the x-ray beam as it impinges on the sclera or other surface. As will be described in greater detail below, the laser pointer can also serve an important purpose in the imaging subsystem which is to provide a visual mark (FIG. 3) 1570 on a surface of an eye 1600 when the eye is imaged by the camera 1550 and digitized or followed in the imaging subsystem. With the visual mark 1570 on the digitized image and the angles of incidence 1510, 1520 of the laser beam 1500, computer generated projections 1700, 1730 of the x-ray (or laser) can be produced on a computer-generated (virtual) retina 1720. In some embodiments, the projections 1700, 1730 are the same, and in some embodiments, the projections can be distinct. For example, in some embodiments, the projection 1700 external to the eye may have different characteristics (e.g., trajectory, penumbra, etc.) than does the projection 1730 within the eye. The computer-generated virtual retina 1720 (FIG. 3) is described in further detail below and is a component of a virtual ocular model and is obtained via real data from an imaging system such as, for example, an OCT, CT Scan, MRI, A or B-scan ultrasound, a combination of these, or other ophthalmic imaging devices such as a fundoscopy and/or scanning laser ophthalmoscopy. In addition to the retina, x-ray delivery to any structure within the eye can be depicted on the virtual ocular model 1725. As shown in FIG. 3, laser beam 1500 is shown as the mark 1570 on screen 1590, which is a depiction of the image seen by the camera 1550 and then in digitized form within the treatment planning system 800. With angles θ 1520 and φ 1510 and the location of the mark 1570 of the laser pointer on the digitized image of the eye 1600, the path 1730 through a “virtual eye” 1725 can be determined in a computer system 1710. If the position is not correct, a signal can be sent back to the electromotive module in order to readjust the targeting point and/or position of the laser/x-ray. In certain embodiments, a second camera can be used to so as to detect the angles of the laser pointer and x-ray beam. These angles can be used to detect the direction of the x-ray beam and send a signal to the electromotive system for re-positioning. This feedback system can ensure proper positioning of the electromotive subsystem as well as correct dosing of the x-ray irradiation to the eye. In some embodiments, an analogue system is used to detect the position of the eye. In these embodiments, the target structure, the eye, is assumed to be in a position and the x-ray control system positions the x-ray source around the globe of the eye, then applying the pre-determined amount of radiation to the eye structure. In certain embodiments, as depicted in FIG. 1E, a physical connection to the eye is used for direct coupling between the eye and the radiotherapy system. In these embodiments, a connection between the eye and the system can be mediated by a lens, such as a scleral or corneal contact lens 940. A physical link between the lens 940 and the system 10 is then provided by structure 175 which directly links to the radiotherapy system 10. The scleral lens 940 can be a soft or hard lens. The lens 940 can further contain one or more connections so that suction can be applied to the sclera so as to stabilize the eye during the therapy. The scleral lens 940 and associated attachments can be used to localize the eye in space. When the position of the sclera is known with the lens, the position of the eye is known as well. The eye is then coupled to the radiotherapy device 10. In some embodiments, the connection between the contact lens and the radiotherapy device 10 is a non-mechanical connection in that the connection is an optical one such as with a laser pointer or one or more cameras to detect the actual position of the eye relative to the radiotherapy system. The position of the eye in physical space is used to simulate the position of the beams in the virtual eye model and then back to the physical world to place the x-ray system to deliver the desired beam direction, angles, positions, treatment times, etc. In some instances, it is desirable to know the scatter dose of the x-ray beam being delivered to a treated structure within the eye. For example, when neovascularization is being treated in the retina with a beam traveling through the sclera, scatter to the lens or optic nerve may be modeled. In further instances, it may be desired to know the dose to the neovascular membrane on the retina, the primary structure to be treated. Imaging Subsystem A fourth advantageous feature of the present disclosure is the imaging subsystem 400, which can also serves as an eye tracking system (FIG. 4) and offers the ability to couple patient movement or eye movement with the other subsystems above. This subsystem 400 advantageously ensures that the patient's eye 2010 does not grossly move out of the treatment field 2060. Camera 2055 can be the same camera 1550 in FIG. 3. The camera 2055 delivers an image to screen 2050. The imaged laser spot 2052 is also shown on screen 2050. The video screen 2050 can be the same video screen 1710 in FIG. 3. Field 2060 in FIG. 4 is the zone within which the eye can move; if the eye 2010 moves outside the zone 2060 on the screen, then the radiation source is either turned off, shuttered off, or otherwise disengaged from the eye 2010. In some embodiments, when an image of the eye 2030 reflects that the eye 2010 has moved out of field 2060, a signal 2090 is sent to the x-ray control system (FIG. 2A) to turn the shutter off. Aside from ensuring that the eye remains within the treatment field, the imaging system couples to the other subsystems by enabling projection of the laser pointer/x-ray beam 2052 on the back of the computer generated virtual eye. In some embodiments, the imaging subsystem is composed of two or more cameras which are used to create a three-dimensional rendering of the eye in space, the three-dimensional rendering then integrated into the overall treatment scheme. Treatment Planning System The treatment planning system 800 is, in part, a virtual system and is depicted in FIG. 1A; it integrates all of the inter-related modules and provides an interface for the health care provider as well. The planning system 800 is the “brains” of the system 10 and provides the interface between the physician prescribing the therapy and the delivery of the therapy to the patient. The treatment planning system integrates anatomic, biometric, and in some cases, geometric assumptions about the eye “the virtual eye model” with information about the patient, the disease, and the system. The information is preferably incorporated into a treatment plan, which can then direct the radiation source to apply specific doses of radiation to specific regions of the eye, the doses being input to and output from the treatment planning system 800. In certain embodiments of the treatment planning system 800, treatment with radiation may be fractionated over a period of days, weeks, or months to allow for repair of tissues other than those that are pathologic or to be otherwise treated. The treatment planning system 800 can allow the physician to map the treatment and dose region and to tailor the therapy for each patient. Referring to FIG. 2E, the treatment planning system 800 forms the center of a method of treatment using radiosurgery system 10. In certain embodiments, the imaging module 400 of the system 10 includes an eye registration and imaging system 810. In certain embodiments, the eye-tracking system is configured to track patient movement, such as eye movement, for use by the treatment planning system 800. The eye-tracking system 810 can calculate a three-dimensional image of the patient's eye via physician inputs, and can include real-time tracking of movement of the patient's eye. The eye-tracking system obtains data that becomes a factor for determining radiotherapy treatment planning for a number of medical conditions relating to the eye, as described above. For example, the eye-tracking system may create an image of the posterior region of the patient's eye using the data it obtains. In certain embodiments, the data can be transferred via cable communication or other means, such as wireless means, to the processing module 140 of the radiotherapy treatment system 10. In certain embodiments, the processing module 140 may process data on the patient's eye and present an image of the patient's eye on the interface display 130. In certain embodiments, the interface display 130 may present a real-time image of the patient's eye, including movement of the eye. In certain embodiments, the eye-tracking system obtains data on the patient's eye while the patient's face is placed approximately upright on and secured by the articulated head restraint 160 such that the patient's eyes face substantially forward, in the direction of the imaging module 400. In certain embodiments, the eye-tracking system may include an alignment system, adjustable using a joystick. The joystick can be tilted horizontally, vertically, or both horizontally and vertically, on a fixed base, in order to adjust the location and/or image displayed on the interface display 130 by the imaging module 400. Another feature of the present disclosure is an integrated plan for treatment. The scale of the device as well as a limitation that the device treat a specific anatomy limits the scope of the treatment planning system which also allows for economies of scale. It is preferable that the x-ray beams be focused so that they apply radiation selectively to target regions of the eye and not to other regions of the eye to which high x-ray doses could be toxic. However, in some embodiments, the eye is the only anatomic region that is treated. In certain embodiments, the retina is the target for the ophthalmic treatment system; one or more beams would be directed to regions of the retina as they pass through the sclera. For treatment planning purposes, it is preferable to know the three-dimensional position of the eye and retina with respect to the output beam of the system. The treatment planning system incorporates detailed images and recreates the geometry of the eye and subsequently directs the x-ray system to manipulate the x-ray output so that the output beam points in the target direction. In some embodiments, the x-ray system is directed and moved automatically. The treatment planning system 800 may utilize, or be coupled to, imaging systems such as, for example, optical coherence tomography systems (OCT), ultrasound imaging systems, CT scans, MRI, PET, slit lamps microscopy systems, direct visualization, analogue or digital photographs (collectively referred to as Biometry Measurements 820). In some embodiments, these systems are integrated into real-time feedback systems with the radiotherapy device such that second be second system updates of eye position and status can take place. Although relatively sophisticated, the system 800 would be limited to the ophthalmic region and therefore takes advantage of specific imaging equipment only available for the eye. In some embodiments, the treatment planning system incorporates the entire soft tissue and bony structures of the head of a patient. The model incorporates all the anatomic structures so that obstructing anatomic regions can be excluded from the treatment. For example, the treatment plan incorporates the nose, the forehead, and associated skin and cartilage to dictate the directionality of the radiotherapy beam with respect to the eye. In some embodiments, these structures are related to the global coordinate system and aid in tracking and treating regions of the eye. In some embodiments, the treatment planning system incorporates physical modeling techniques such as Monte Carlo (MC) simulation into the treatment plan so that the real time x-ray doses can be delivered to the ocular structures. In these embodiments, the inputs to the treatment planning system 800 are integrated with Monte Carlo simulation of the planned treatment plan and the effects of the plan, both therapeutic and potentially toxic, can be simulated in real time. The method depicted in FIG. 2E is as follows. Biometry measurements 820 and user controls 875 such as structure and dose are entered into the treatment planning system 800. Other inputs include information from an eye registration and imaging system 810. The output from the treatment planning system 800 consists of commands sent to the x-ray source and electromotive subsystem to move and position the source as well as to direct the on and off times (dose control) of the x-ray source 830. After a dose 840 is delivered, the treatment planning system 800 then signals x-ray source movement to deliver an additional dose 840. This cycle can iterate several times until the treatment is completed. For example, if a single beam can deliver the desired amount of radiation, the treatment planning system determines the direction of the xray beam relative to the patient specific anatomy and then the xray source is turned on. If two beams are desired to create the dose accumulation to the target, then the treatment planning system determines the size of the beams, their angles relative to the target and the specific patient anatomy, then applies the first beam to the eye in a first angle and a second beam at a second angle relative to the target. A similar method is used for three, four, five, or six beams. Monte Carlo Simulation and Experimental Validation Monte Carlo (MC) simulation is the gold standard to model x-ray absorption, scatter, and dosing to structures impinged on by the x-ray. Monte Carlo methods are a widely used class of computational algorithms for simulating the behavior of various physical and mathematical systems, and for other computations. They are distinguished from other simulation methods (such as finite element modeling) by being stochastic, that is, non-deterministic in some manner. Monte Carlo simulation forms an integral part of all treatment planning systems and is used to assist in treatment planning where radiation is involved. Monte Carlo simulation can also be used to predict and dictate the feasibility and other elements of the radiotherapy system 10 (e.g., optimization of the collimator and treatment planning schemes); for example, the collimation designs, the energy levels, and the filtering regimes, can be predicted using Monte Carlo simulation. The designs predicted by Monte Carlo simulation should be experimentally verified and fine-tuned but MC simulation can predict the initial specifications. In some embodiments, MC simulation is integrated into the treatment planning systems and in other embodiments, MC simulation dictates the algorithms used by the treatment planning system 800. MC simulation is often used in the back end of the treatment planning system to create boundaries of treatment. For example, MC simulation can predict the penumbra of an x-ray beam. The penumbra of the x-ray beam is used in the virtual world to direct the x-ray beam and set boundary limits for the x-ray beam with respect to the lens, optic nerve, etc. In some embodiments, age-related macular degeneration (AMD) is the disease treated with the x-ray generation system. In some embodiments, the x-ray system 10 is used to treat post-surgical scarring in procedures such as laser photocoagulation and laser trabeculotomy or laser trabeculectomy. In some embodiments, the x-ray system is used to treat ocular tumors. Importantly, the x-ray treatment system allows for selective irradiation of some regions and not others. In some embodiments, radiation is fractionated over a period of days, months, or weeks to allow for repair of tissues other than those which are pathologic or to be otherwise treated. In order to A) prove that lower energy radiation can be delivered to the retina to treat AMD in a clinically relevant time period with a device on the size scale in FIG. 1, B) from a clinically relevant distance, and C) optimize some of the parameters of the treatment system for initial design specifications for the x-ray tube, an MC simulation was performed. Eye geometry was obtained and a two-dimensional, then three-dimensional model created, as shown in FIG. 5. Soft tissue and hard tissue (e.g., bone 2060) was incorporated into the model in FIG. 5. FIG. 6 depicts different beam angles (2100, 2110, 2120, 2130, 2140) which were modeled in this system to simulate therapy to the macula to treat AMD in this example. In this simulation, each beam enters the eye at a different angle from the geometric center 2094, or treatment axis 2096, of the eye. Each beam cuts a different path through the eye and affects different structures such as the optic nerve 2085, lens 2075, sclera 2076, cornea 2080, fovea 2092, etc. differently depending on the path through the eye. For example, beam 2120 enters the eye directly through the eye's geometric axis. A series of x-ray sources were modeled using a range of energies from 40 KeVp to 80 KeVp. A proposed collimation scheme was used to produce a near parallel beam as was a series of different filters (1-3 mm thickness aluminum). The combination of angle of entry of the beam, photon energy of the beam, and filtration of the beam all factor into the relative amounts of energy deposition to the various structures. FIGS. 7A-7E depict some of the results from the MC simulation showing that the lower energy x-ray beams can indeed penetrate through the sclera 2200 and to the retina 2250 with minimal scatter to other ocular structures such as the lens 2260. The higher density of dots indicate actual x-ray photons in the MC simulation so that the absence of photons on the lens for example (FIG. 7A) in certain beam angles is indicative of lack of photon absorption at the level of the lens. These simulations reveal that beams with widths from about 0.5 mm to about 8.0 mm will avoid critical structures of the anterior portion of the eye at certain angles off of the central axis. FIG. 7F depicts the results of a simulation of a series of beams which enter the eye through the pars plana region (FIGS. 7D-E). This simulation was done to minimize dose to the optic nerve with the beams in 7D and 7E which minimize dose to the structures of the front of the eye. The beam shown in 7E has the most optimum profile with respect to the optic nerve 2085 and lens 2260. Simulations with this beam are performed by directing the beam toward the eye through the pars plana direction and from various directions a-g (FIG. 7F) which correspond to varying nasal-temporal and caudal-cranial positions. In some embodiments, these beams are between 2 and 5 mm in diameter and have an energy of between 60 KeV and 150 KeV. In some embodiments, certain angles or directions are identified as corresponding to certain structures that are desirable to avoid during treatment. Consequently, the angles that correspond to these structures are not used for the trajectory of the x-ray during treatment, thus avoiding the optic nerve. For example, in some embodiments, the angle b may correspond with an x-ray trajectory that would pass through the optic nerve. In these embodiments, the angle b may not be used to reduce the likelihood of exposing the optic nerve to the x-ray. Accordingly, the angles can be used to optimize the treatment plan and present as little risk as possible to existing structures that are sensitive to radiation. FIG. 7F depicts eight trajectory angles. In some embodiments, the x-ray trajectory can include less than eight or more than eight trajectory angles. For example, in some embodiments, four, six, ten, or twelve trajectory angles are presented. In these embodiments, optimal beam directions are provided by those beams (e.g., b, a, g, h, f) which are considered to come from the nasal direction. The lower picture in FIG. 7F shows the dose on the retina of the angled beams in the picture above. The predicted isodose fall-off for these beams is greater than 90% within 0.05-0.1 mm of a 1-2 mm beam which is less than ten percent. Region 2290 depicts a region of higher dose within the iso-dose profile. This higher dose region 2290 results from the fact that the beam enters the eye at an angle. The increase in the dose is moderate at approximately ten to twenty percent higher than the average for the entire region. Furthermore, because there are multiple beams entering the eye, the areas of increased dose 2290 average out over the region of the retina. Therefore the higher dose region is incorporated into the treatment plan to account for the uneven distribution. FIG. 8 is a quantitative, graphical representation of the data in FIG. 7. What is shown is the surface to retina dose for different x-ray tube potentials and for different aluminum filter thicknesses 2385. This graph is the data for beams 2100 and 2140 in FIG. 6. The ratio of surface to retina dose is shown in FIG. 8 (i.e., the dose of entry at the sclera to the dose at the retina); what can be seen is that the dose to the sclera is not more than 3 times the dose to the retina for most beam energies (tube potentials). For energies greater than about 40 KVp, the ratio of surface dose to retina dose 2375 is less than about 3:1. What this says is that if the spot were maintained in the same position as 25 Gy was delivered to the retina, the maximum dose to the sclera would be 75 Gy. Of course, as the beam is moved around the eye, the 75 Gy is averaged over an area and becomes much less than the dose of 25 Gy to the macula. This is depicted in FIG. 6 which shows the results of the movement to different points along the sclera with the x-ray beam. At 80 KeVp 2380, the ratio of surface to depth dose is closer to 2.2 with 1 mm of filtering. These data are integrated into the treatment plan and the design of system 10 and, in part, determine the time and potential of the x-ray tube. Therefore, in some embodiments, tightly collimated x-ray radiation at energy levels greater than 40 keV with greater than 1 mm of filtration delivered through the pars plana region of the eye can be used to deliver a therapeutic dose of radiation to the retina with a relatively lower dose buildup on the sclera, the lens, or the optic nerve than the therapeutic dose delivered to the retina. For example, if a therapeutic dose to the retina is 25 Gy or less, the dose to any region of the sclera penetrated by the beam will be less than 25 Gy. FIG. 9 is a bar graph representation showing scatter doses to ophthalmic regions other than the retina and comparing them to the retina. As can be seen in the logarithmic figure, the dose to the lens 2400 (beams 2100 and 2140) and optic nerve 2410 (beam 2140 alone), the two most sensitive structures in the eye, are at least an order of magnitude lower than the dose delivered to the macular region 2450 of the retina. Therefore, a 25 Gy dose of radiation can be delivered to a region of the retina through the pars plana region of the eye with at least an order of magnitude less radiation reaching other structures of the eye such as the lens, the sclera, the choroids, etc. These simulations dictate the design specifications for the x-ray generation systems and subsystems. These simulations can also be integrated into the treatment planning system 800 as a component of the plan. For example, the planning system, which incorporates the unique anatomy of each patient, can simulate the amount of radiation delivered to each structure dependent on the angle and position of delivery through the sclera. Depending on the angle, beam size, and beam energy, the radiation delivered to the ocular structures will vary and alternative direction can be chosen if the x-ray dose is too high to the structures such as the lens and the optic nerve. To verify the validity of the MC simulations and verify that the eye can be assumed to be a sphere of water, a human cadaver eye 2500 was obtained and the ratio of surface to depth dose of an x-ray source was experimentally determined. Among other things, parameters of an emitted x-ray beam 2510 were compared with parameters of the beam 2520 emerging from the eye 2500. The ratio from the experimental set-up in FIG. 10 proved to be identical to that when the eye is assumed to be water in the MC simulations. For example, the ratio of surface to 2 cm depth for 80 KeV with 2 mm filtration was indeed 3:1 as predicted by the MC model. Additional work verified that the dose fall off at each depth was likewise identical. This experimental work confirms that the modeling predictions using MC are accurate for ocular structures and that secondary interactions typically required of MC simulations with high energy x-rays are not necessary for lower energy x-rays. These observations significantly simplify the MC simulations and allow for quick real time simulations at the time of treatment planning. Furthermore, the design criteria which are used in the system 10 design can be accurately modeled using water for their prediction. Further analysis and experimentation reveals that to deliver 25 Gy to the macula in a clinically relevant time period (e.g., not longer than 30 minutes), the system in FIG. 1 will draw about 1 mA to about 40 mA of current through the x-ray source. The exact number of mA depends on how close the x-ray tube is to the eye. If the tube is very close to the eye, then the system will draw less current than if the system is further away from the eye. In some embodiments, it may be that the about 15 Gy to about 25 Gy needs to be delivered to the retina in a period shorter than 10 minutes. In such an embodiment, the tube current may need to be upwards of 25 mA and the x-ray tube closer than 25 cm from the retina. These parameters are for energies of 60-100 KeV and 1-3 mm filtration with aluminum, lead, tungsten, or another x-ray absorbing metal. In certain embodiments, the collimator is less than about 5 cm from the anterior surface of the eye and the photon energy is about 100 KeV with 1, 2, 3, 4, or 5 beams with diameters of between 1 mm and 6 mm entering the eye through the infero-nasal region. The nasal region affords the greatest distance from the optic nerve and the inferior region is preferred so as to avoid the bones of the nose and the anterior skull. These assumption are for an eye which is positioned to look straight outward from the skull. In this embodiment, the treatment time may be less than about 5 minutes within a range of currents between 15 mA and 40 mA. Each beam of the 1-4 beams can be turned on for between 3 seconds and 5 minutes. In some embodiments, 3 beams are used for the treatment. In some embodiments, the collimator is placed within 3 cm from the surface of the eye, and in some embodiments, the collimator is placed within 10 cm of the surface of the eye. FIG. 11A depicts the results of a collimated x-ray beam 2600 which penetrates approximately 2 cm through water (or an eye) 2630 where the collimator is approximately 5.0 cm from the surface of the water. As can be seen in FIG. 11A2, there is a small penumbra width 2610 about an original beam width 2620 after penetration through the eye which is less than 10% of the shaping beam shown in FIG. 11A1. These data incorporate both divergence as well as isodose drop off and reveal that for a collimator within about 5 cm of the target, the penumbra can be very small. FIG. 11B depicts a graphical representation of the penumbra from measurements within a film. Delta 2650 represents the absorption in the energy between the surface and the depth as recorded by x-ray sensitive film. The tails seen in 2640 versus 2630 indicate a small degree of penumbra effect as the beam loses energy through the eye. Indeed, the penumbra for a 0.5 mm to 6 mm spot size can be as low as 0.01% and as high as ten percent depending on the placement of the collimators with respect to the eye. Combination Therapy Radiotherapy device 10 can be used in combination with other therapeutics for the eye. Radiotherapy can be used to limit the side effects of other treatments or can work synergistically with other therapies. For example, radiotherapy can be applied to laser burns on the retina or to implants or surgery on the anterior region of the eye. Radiotherapy can be combined with one or more pharmaceutical, medical treatments, and/or photodynamic treatments or agents. As used herein, “photodynamic agents” are intended to have their plain and ordinary meaning, which includes, without limitation, agents that react to light and agents that sensitize a tissue to the effects of light. For example, radiotherapy can be used in conjunction with anti-VEFG treatment, VEGF receptors, steroids, anti-inflammatory compounds, DNA binding molecules, oxygen radical forming therapies, oxygen carrying molecules, porphyryn molecules/therapies, gadolinium, particulate based formulations, oncologic chemotherapies, heat therapies, ultrasound therapies, and laser therapies. In some embodiments, radiosensitizers and/or radioprotectors can be combined with treatment to decrease or increase the effects of radiotherapy, as discussed in Thomas, et al., Radiation Modifiers: Treatment Overview and Future Investigations, Hematol. Oncol. Clin. N. Am. 20 (2006) 119-139; Senan, et al., Design of Clinical Trials of Radiation Combined with Antiangiogenic Therapy, Oncologist 12 (2007) 465-477; the entirety of both these articles are hereby incorporated herein by reference. Some embodiments include radiotherapy with the following radiosensitizers and/or treatments: 5-fluorouracil, fluorinated pyrimidine antimetabolite, anti-S phase cytotoxin, 5-fluorouridine triphosphate, 2-deoxyfluorouridine monophosphate (Fd-UMP), and 2-deoxyfluorouridine triphosphate capecitabine, platinum analogues such as cisplatin and carboplatin, fluoropyrimidine, gemcitabine, antimetabolites, taxanes, docetaxel, topoisomerase I inhibitors, Irinotecan, cyclo-oxygenase-2 inhibitors, hypoxic cell radiosensitizers, antiangiogenic therapy, bevacizumab, recombinant monoclonal antibody, ras mediation and epidermal growth factor receptor, tumor necrosis factor vector, adenoviral vector Egr-TNF (Ad5.Egr-TNF), and hyperthermia. In some embodiments, embodiments include radiotherapy with the following radioprotectors and/or treatments: amifostine, sucralfate, cytoprotective thiol, vitamins and antioxidants, vitamin C, tocopherol-monoglucoside, pentoxifylline, alpha-tocopherol, beta-carotene, and pilocarpine. Antiangiogenic Agents (AAs) aim to inhibit growth of new blood vessels. Bevacizumab is a humanized monoclonal antibody that acts by binding and neutralizing VEGF, which is a ligand with a central role in signaling pathways controlling blood vessel development. Findings suggest that anti-VEGF therapy has a direct antivascular effect in human tissues. In contrast, small molecule tyrosine kinase inhibitors (TKIs) prevent activation of VEGFRs, thus inhibiting downstream signaling pathways rather than binding to VEGF directly. Vascular damaging agents (VDAs) cause a rapid shutdown of established vasculature, leading to secondary tissue death. The microtubule-destabilizing agents, including combretastatins and ZD6126, and drugs related to 5,6-dimethylxanthenone-4-acetic acid (DMXAA) are two main groups of VDAs. Mixed inhibitors, including agents such as EGFR inhibitors or neutralizing agents and cytotoxic anticancer agents can also be used. Radiodynamic Therapy Radiodynamic therapy refers to the combination of collimated x-rays with a concomitantly administered systemic therapy. As used herein, the term “radiodynamic agents” is intended to have its ordinary and plain meaning, which includes, without limitation, agents that respond to radiation, such as x-rays, and agents that sensitize a tissue to the effects of radiation. Similar to photodynamic therapy, a compound is administered either systemically or into the vitreous; the region in the eye to be treated is then directly targeted with radiotherapy using the eye model described above. The targeted region can be precisely localized using the eye model and then radiation can be precisely applied to that region using the PORT system and virtual imaging system based on ocular data. Beam sizes of 1 mm or less can be used in radiodynamic therapy to treat ocular disorders if the target is drusen for example. In other examples, the beam size is less than about 6 mm. While certain aspects and embodiments of the disclosure have been described, these have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms without departing from the spirit thereof. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.
053751531	summary	BACKGROUND OF THE INVENTION The present invention relates generally to nuclear :fuel assemblies for use in nuclear reactors. More specifically, the present invention relates to a coolant vent duct for use in light water reactors, and more particularly to either a boiling water reactor or a pressurized water reactor. The coolant vent duct could be applied in conjunction with a part length fuel rod, with a water rod, with a water/fuel rod or simply by itself. In addition, the present invention relates to a part length fuel rod having an upper end fitting which functions to separate at least a portion of the liquid and the vapor portions of two phase flow. It is known to generate large amounts of heat and energy through nuclear fission in a nuclear reactor. Energy is dissipated as heat in elongated nuclear fuel rods. Typically, a nuclear fuel assembly includes a number of nuclear fuel rods that are grouped together to form a nuclear fuel assembly. Such fuel assemblies include a number of elongated rods supported between upper and lower tie plates. It is known in boiling water reactor (BWR) fuel designs to include within fuel assemblies part-length fuel rods. Accordingly, some of the fuel rods in a bundle are truncated at some intermediate elevation in the core. This leaves an unfilled coolant channel above that elevation. By providing a truncated fuel rod, several important benefits are achieved. For example, there is a neutronic advantage in increasing the amount of fuel in the bottom of the core as compared to the top of the core. A more axial uniformity in water to fuel ratio is thereby achieved with an associated improvement in fuel cycle costs, increased shut-down margin, reduced pressure drop (principally because of increased flow area, but decreased wetted surface also reduces the pressure drop), and increased core stability because the pressure drop reduction occurs at the top part of the bundle where two phase pressure drops are most significant. Potentially, the part-length fuel rod could yield a small critical heat flux (CHF) benefit because of the reduced mass flux in the top part of the bundle. This potential is generally not achieved. An important factor is considered to be that the simple truncation of the part-length fuel rod results in large open subchannels that have less power density than the other subchannels in the bundle. This results in significant non-uniformities of subchannel enthalpy rises. Effectively, the flow in the other regular subchannels is reduced by a factor greater than one would expect merely from the increase in the bundle flow area that occurs above the top end of a part length fuel rod. Mixing devices and flow strippers have been utilized in an attempt to offset this problem somewhat at the expense of added pressure drop. A number of part length fuel rod constructions have been utilized in the prior art. U.S. Pat. No. 4,664,882 discloses a segmented fuel and moderator rod and fuel assembly for a boiling water reactor. The segmented rod has a lower fuel region and an upper moderator region for passing coolant through the upper portion of the boiling water reactor core which is normally undermoderated. The segmented rod displaces one or more conventional fuel rods in the fuel bundle. U.S. Pat. No. 2,998,367 discloses a core that includes short fuel rods, rods of intermediate length, and rods extending the full height of the core, immersed in light water. U.S. Pat. No. 4,789,520 discloses in an embodiment a fuel assembly having six fuel rods, each having a short fuel effective length portion in comparison to other fuel rods that are included in order to reduce the pressure loss within the fuel assembly. U.S. Pat. No. 4,957,698 discloses a fuel design that preferentially directs more unvoided water coolant into the upper region of the fuel assembly. This allows relatively more fuel to be placed in the lower portion of the fuel assembly. The arrangement is designed to allow moderation of neutrons in the upper portion of the assembly while preserving a higher volume of fuel in the lower portion. The larger number of fuel rods that can be used in the lower portion reduces the linear heat generation (power peaking) in the assembly. U.S. patent application Ser. No. 07/737,859, filed on Jul. 30, 1991, entitled: "IMPROVED FUEL ASSEMBLY FOR BOILING WATER REACTORS", and assigned to the assignee of this patent application discloses, in part, a fuel assembly. SUMMARY OF THE INVENTION The present invention provides a coolant vent duct structure to be preferably located above a part-length fuel rod portion that improves critical heat flux (CHF) performance with respect to typical part-length fuel rods without significant degradation of the benefits that are achieved by using such a system, e.g., improved fuel utilization, stability, and shut down margin. The present invention improves CHF performance by providing a better matching of subchannel hydraulic resistance to subchannel power in the top part of the bundle for the subchannels adjacent to these rods. A reduction of active flow channel enthalpies, i.e., void fraction, in the top part of the bundle is achieved by the structure of the present invention. The inventive coolant vent duct is not limited to use above a part-length fuel rod, it may be used above a water rod or a water/fuel rod or alone. To this end, in an embodiment, the present invention provides a duct structure that provides a hollow tube that is located above and is mechanically connected to the part-length fuel rod of a boiling water reactor fuel assembly. The duct structure can include an extension tube having at least one wall member defining an enclosed flow path therethrough, the extension tube being coupled to a portion of the part-length fuel rod so as to be disposed axially above the part-length fuel rod, and including at least one inlet opening, for allowing a portion of a fluid that surrounds the rod, that initially comprises a two phase mixture of steam and liquid, to enter the enclosed fluid path, and including at least one outlet opening located above the inlet opening, the extension tube can further include means for separating at least some of the steam located in the fluid from the liquid located therein. The structure allows steam to bypass the upper active portions of the fuel assembly. To accomplish this separation, the means can direct liquid water from the inlet holes while allowing steam to enter, or the means can entail directing water out of the duct while permitting the steam flow to continue flowing upwards inside the duct. In an embodiment, the duct includes a transition section and an upper section, the upper section having an outer perimeter greater than the outer perimeter of the fuel rod below. The inlet holes can be located in the upper section or the transition section or both. The upper section need not be round in cross section but preferably is round and is larger in diameter than the fuel rod below. In one form, the duct is a circular tube that has holes drilled into it and the transition piece merely provides a mechanical connection of the lower part-length fuel rod and the upper extension tube. This arrangement has some capability for separating steam from liquid because, owing to their greater inertia, the liquid drops flowing upwards towards the inlet holes are not as readily turned into the holes as is the steam. A drawback, especially when only a small amount of flow is taken into the extension tube, is that the liquid film that is on the surface of the rod can be drawn more readily into the holes, making separation performance less than desired. In an embodiment, the means for separating liquid from steam is located on an outer portion of the wall outside the enclosed area in juxtaposition to the inlet opening or openings. The means for separating directs liquid away from the inlet opening causing the fluid that enters an inlet opening to comprise a greater percentage of steam. For example, the means can comprise a V-shaped member extending from the outer wall upstream and adjacent to an opening. Assembly of this invention into the fuel bundle can impose dimensional limits on the radial extent of the V-shaped members or other means for diverting liquid films and drops from the inlet holes. For example, assembly of the bundle typically begins with a skeleton consisting of the lower tie plate, tie rods, and all the spacers. The remaining rods including the structure of this invention are then inserted through the openings in the spacers. The width of the openings for those cells which will contain this invention will be only slightly greater than the outside diameter of the upper tube. Thus, the radial extent of the means for diverting liquid away from the holes is limited to fall within the square envelope of the openings in the upper spacers. Once inserted through the spacers this invention may require rotation for optimum alignment of the inlet openings relative to the surrounding subchannels. An embodiment demonstrates that more flexibility as to the radial extent of the protruding members can be gained by locating the inlet holes into a hollow transition piece (hollow except at the bottom thereof) and which would have a local diameter (not including the protruding members) that is less than the diameter of the upper tube. An exemplary embodiment shows a different means of achieving sufficient separation performance. The liquid diverter is located upstream (i.e., below) of a group of inlet openings and serves to divert liquid away from all the openings in this group. For simplicity, the inlet openings are in the duct and a transition connector piece serves as the diverter. This means of liquid diversion includes one or more protrusions from the minimum section of the transition connector. Generally, there will be at least one protrusion at the top as the connector expands to the diameter of the upper tube. To be effective, the protrusions must have a reasonably sharp break in their surface so that the liquid film flowing radially outwards along the face of the protrusion will depart the surface and continue to move radially away from the transition connector piece. A double protrusion transition connector piece with a number of geometric characteristics to promote separation of liquid and steam can be utilized. The geometric characteristics are: (1) a smooth and gradual reduction in diameter moving axially upwards along the transition connector piece from the bottom end; the diameter is decreased so the subsequent protruding surfaces present a greater diversion of the overall flow from an axial to a radial direction; the diameter reduction is gradual so that the liquid film stays attached to the surface upstream of a first protrusion; PA1 (2) the first protrusion is shaped so that the liquid film will follow a smooth curved arc path as its flow direction is changed to have a large radial component; PA1 (3) the first protrusion ends in a sharp break and has only a small axial extent (i.e., the transition piece diameter is again reduced); this second reduction in diameter is done purposefully so that the recirculating flow behind the separating film acts to promote radial separation by providing a recirculating stream that joins with the separating film in a smooth tangential manner; the film separates as a continuous sheet of liquid that collides with the main axial flow of liquid drops and steam; this collision imparts outward radial momentum to the liquid drops that were flowing axially so as to move liquid in general radially away from the downstream inlet openings; PA1 (4) the second protrusion occurs as the transition connector piece is flared outwards to have the diameter of the upper tube. In this embodiment, the first protrusion takes the form of a ring shaped tapering disk located about the small diameter section of the transition connector piece. Another approach would be to use partial or segmented rings that are displaced axially that do not have a full 360.degree. extent at any one location. This approach can allow steam to pass more easily towards the inlet holes by flow around the ends of the liquid film sheets as opposed to having to penetrate the sheets as they start to breakup into drops. Another approach to separate liquid from steam ahead of the inlet holes would be to use turning vanes to give an azmathal or circular component to the flow in addition to its axial component. The addition of a swirling or twisting component to the flow is a common approach to achieving separation of liquid from steam since the liquid has more of a tendency to move outwards in response to centrifugal forces than does the steam. In another embodiment, the means for separating is located within the enclosed area of the duct, for example, the means for separating can comprise means for imparting a centrifugal force to the two phase mixture. If desired, at least two means for separating can be provided, one located within the enclosed area of the duct and the other on an outer wall portion of the duct to achieve a more complete separation of the steam from the liquid. The present invention provides a fuel rod for a light water reactor having a part length fuel rod portion and a reflex upper end fitting for separating at least a portion of the liquid and the vapor of two phase flow. The reflex upper end fitting is disposed axially above the part length fuel rod and in contact with the downstream end of the part length fuel rod. The reflex upper end fitting comprises a section having a diameter tapering downwardly into a reduced diameter and flaring thereafter into a second diameter terminating in a sharp break at a line around its perimeter, the tapering and flaring producing a smooth flow path for propelling fluid flowing therealong, radially inwardly and then outwardly from the downstream end of the part length fuel rod.
051587424	description	MODE(S) FOR CARRYING OUT THE INVENTION Illustrated schematically in FIG. 1 is a portion of a nuclear reactor power plant having a reactor steam isolation cooling system designated 10 in accordance with an exemplary embodiment of the present invention. The cooling system 10 includes a containment building 12 having a plurality of walls including a top containment wall 14 which may be conventionally formed of concrete with a metal or steel inner liner. A conventional reactor pressure vessel 16 is disposed inside the containment building 12 and includes a conventional nuclear reactor core 18 in an exemplary form of a boiling water reactor (BWR) which is operable for generating reactor steam 20 from water 20a contained therein. During normal operation, the reactor core 18 boils the water 20a by heat released from nuclear fission for generating the reactor steam 20. Conventional steam separators and steam dryers (not shown) remove moisture from the reactor steam 20, and then the steam 20 is conventionally discharged from the pressure vessel 16 through a conventional main steam outlet 22 and through a conventional main steam outlet conduit 24 which extends through the containment building 12. The reactor steam 20 is channeled for example to a conventional steam turbine (not shown) for generating electrical power from a generator joined thereto. Water, in the form of feedwater 20b is returned to the pressure vessel 16 through a conventional feedwater conduit 26 through the containment building 12 to a feedwater inlet 28 of the pressure vessel 16. A conventional feedwater sparger (not shown) distributes the feedwater 20b inside the pressure vessel 12 wherein it mixes with the reactor water 20a therein. In the event of isolation of the reactor core 18, which may occur upon tripping of the steam turbine for example, the reactor core 18 is conventionally shut down, with the reactor core 18 still providing decay heat which continues to boil the reactor water 20a to generate the reactor steam 20 for a certain time period. Or, in an alternate situation, the reactor steam 20 may be released inside the containment building 12 by failure of the outlet conduit 24 for example which increases the temperature and pressure therein. The reactor steam 20 generated within the pressure vessel 16 is at an elevated temperature of about 290.degree. C. and at an elevated pressure of about 70 kg/cm.sup.2, for example, which upon release inside the containment building 12 can damage conventional components therein. Accordingly, the isolation cooling system 10 in accordance with the present invention is effective for passively cooling the reactor steam 20 in the event of isolation of the reactor core 18 or in the event of release of the steam 20 inside the containment building 12. In a preferred embodiment, the isolation system 10 further includes an isolation pool 30 disposed outside the containment building 12 and adjacent to the containment wall 14 above the pressure vessel 16. The isolation pool 30 contains pool water 32 which is used as a heat sink for dissipating the heat from the reactor steam 20. The isolation pool 30 also includes a vent 34 extending through a wall thereof and disposed in flow communication between the pool water 32 and the atmosphere outside the containment building 12 which is at atmospheric pressure. The vent 34 allows vapor 32a from the pool water 32 to be discharged from the pool 30 into the atmosphere for releasing heat therein. An isolation condenser 36 in accordance with one embodiment of the present invention extends sealingly through a transfer port 38 in the upper wall 14 between the pool 30 and the containment building 12. The isolation condenser 36 is illustrated in more particularity in FIG. 2 and includes a plurality of parallel, closed, conventional heat pipes 40 each containing a will not contaminate the reactor steam 20 in the event of leakage from the heat pipes 40. Each heat pipe 40 includes a first or hot tube 44 integrally joined with a second or a cold tube 46. The hot tubes 44 are preferably disposed vertically upright inside the containment building 12 and extend downwardly from the upper wall 14, and the cold tubes 46 extend upwardly from the hot tubes 44 inside the isolation pool 30 and are primarily inclined inside the isolation pool 30 at an angle A of about 45.degree., for example, in the preferred embodiment. The hot tubes 44 collectively define an evaporator assembly for heating and boiling the working liquid 42 to form a working vapor 42a which rises naturally upwardly through the hot tubes 44 and into the cold tubes 46. The cold tubes 46 collectively define a condenser assembly disposed under the pool water 32 which are cooled thereby for cooling the working vapor 42a therein to form a working liquid condensate 42b which is returned by gravity, for example, from the cold tubes 46 and into the hot tubes 44 for mixing with the original working fluid 42. The hot tubes 44 are so characterized since the hot reactor steam 20 is suitably selectively channeled therebetween from either the pressure vessel 12 in the event of the isolation occurrence, or from within the containment building 12 in the event of steam release therein. The hot reactor steam 20 heats the working fluid 42 in the hot tubes 44 for removing heat from the reactor steam 20 to form a reactor liquid or condensate 20c which is suitably returned to the pressure vessel 16. The cold tubes 46 are so characterized since they are relatively colder than the hot tubes 44 during operation and are disposed in the relatively cold pool water 32 for cooling the working vapor 42a to form the working condensate 42b, thereby releasing heat into the pool water 32. The heat pipes 40 utilize the heat absorption and release from the change of phase from liquid to vapor and back to liquid for removing heat from the reactor steam 20 and releasing that heat into the pool water 32 for removal from the containment building 12. Although the isolation condenser 36 could be disposed solely outside the containment building 12 or solely within the containment building 12, in the preferred embodiment it is disposed through the upper wall 14 for several reasons. Most importantly, in order to provide an additional or redundant barrier against leakage of the radioactive reactor steam 20 through the walls of the containment building 12, the hot tubes 44 extend downwardly from the upper wall 14 inside the containment building 12 to provide a first barrier, and the radioactive reactor steam 20 is contained solely inside the containment building 12. The cold tubes 46 provide a second or redundant barrier against leakage of the radioactive steam from the containment building 12. The heat pipes 40 themselves therefore provide redundant barriers against leakage of the reactor steam 20 from the containment building 12. In a conventional isolation condenser, for comparison, a conventional heat exchanger or condenser is disposed inside an isolation pool with the reactor steam 20 being channeled inside the tubes forming the heat exchanger. Failure of any of the heat exchanger tubes which leaks the radioactive steam 20 into the isolation pool will therefore release radioactivity through the vent thereof into the atmosphere. However, by utilizing the heat pipes 40, the hot tubes 44 provide the first barrier against leakage of the radioactive reactor steam 20 and, upon any failure of the hot tubes 44, the reactor steam 20 would merely flow inside such failed hot tube 44 and upwardly into the corresponding cold tube 46 which provides the second barrier to prevent its release into the isolation pool 30 and through the vent 34 to the atmosphere. However, since the isolation condenser 36 must itself breach the upper containment wall 14 it is sealingly joined thereto to accommodate pressures within the containment building 12 which may be up to the pressures within the pressure vessel 16 during a steam release condition. More specifically, the isolation condenser 36 preferably includes an annular tube sheet 48 disposed between the hot and cold tubes 44 and 46 which has a suitable thickness T for accommodating any expected pressure loads from the reactor steam 20 channeled between the hot tubes 44. The tube sheet 48 includes a plurality of apertures 50 through which the heat pipes 40 are disposed in sealing contact therewith for preventing leakage of the reactor steam 20 into the reactor pool 30. In a preferred embodiment, the isolation condenser 36 further includes a cylindrical shell 52 surrounding the evaporator assembly of the hot tubes 44 disposed inside the containment building 12 which is sealingly joined to the tube sheet 48. More specifically, the shell 52 includes an annular shell flange 54 at the base thereof which is conventionally fixedly joined to the tube sheet 48 by welding for example. As shown in more particularity in FIG. 3, the tube sheet 48 and shell flange 54 are joined together at a complementary lap joint 56 and a conventional first annular canopy seal 58 is welded to both the tube sheet 48 and the shell flange 54 on the isolation pool side thereof to prevent leakage of the pool water 32 downwardly through the lap joint 56. The first canopy seal 58 also prevents leakage of the reactor steam 20 from within the shell 52 and into the isolation pool 30. The isolation condenser 36 is fixedly joined to the upper containment wall 14 by a plurality of circumferentially spaced apart bolts 60 which extend through respective apertures in the shell flange 54 and are conventionally joined to the upper containment wall 14. The upper wall 14 preferably includes an annular metal ring 62 conventionally formed or cast with the concrete upper wall 14, and a second annular canopy seal 64 is conventionally welded to the ring 62 and the shell flange 54 on the pool side thereof for preventing leakage of the pool water 32 therebetween. The bolts 60 are also conventionally sealed with suitable gaskets for also preventing leakage of the pool water 32 into the containment building 12. It is preferred that the canopy seals 58 and 64 are disposed on the top of the shell flange 54 where they are readily accessible and may be examined during maintenance operations. Furthermore, they prevent pool water 32 from corroding the respective joints between the shell flange 54 and the tube sheet 48 and ring 62. As shown in FIG. 2, each of the hot and cold tubes 44 and 46 includes a proximal end 44a, 46a disposed adjacent to the tube sheet 48, and distal ends 44b, 46b disposed below and above, respectively, the tube sheet 48. As illustrated in FIGS. 4 and 5, two exemplary embodiments of sealingly joining the hot and cold tubes 44 and 46 to the tube sheet 48 may be used. In both embodiments, the proximal ends 44a and 46a are fixedly and sealingly joined to the tube sheet 48. In the first embodiment illustrated in FIG. 4, the hot and cold tubes 44 and 46 are separate members with the proximal ends thereof 44a, 46a extending into the tube sheet apertures 50 from respective sides of the tube sheet 48 and are spaced from each other to form a gap therebetween. The hot and cold tubes 44 and 46 are conventionally welded to the tube sheet 48 at respective bottom and upper surfaces 48a, 48b thereof completely around each tube 44, 46. In this way, the hot and cold tubes 44 and 46 are allowed to freely expand upwardly and downwardly relative to the welds, with the gap between the two proximal ends 44a and 46a allowing for expansion therebetween. Furthermore, the isolation pool water 32 is prevented from leaking into the apertures 50 for preventing corrosion therebetween. In the second embodiment illustrated in FIG. 5, the hot and cold tubes 44 and 46 are again separate members, with the hot tubes 44 extending upwardly completely through the tube sheet apertures 50 with the proximal ends 44a thereof being spaced above the tube sheet upper surface 48b. The hot tubes 44 are conventionally welded to the top surface 48b completely around the hot tubes 44 and below the proximal ends 44a thereof. In this way, the welds prevent leakage of the pool water 32 into the tube sheet apertures 50 for preventing corrosion therebetween. The cold tube proximal ends 46a extend downwardly inside the hot tubes 44 and below the proximal ends 44a thereof, and the cold tubes 46 are conventionally welded completely therearound to the hot tube proximal ends 44a. In this way, the welds similarly prevent the pool water 32 from leaking between the hot and cold tubes 44 and 46 at this joint for preventing corrosion therebetween. Furthermore, the respective welds allow each of the hot and cold tubes 44 and 46 to freely expand and contract upwardly and downwardly relative to the welds. Referring again to FIG. 2, the shell 52 preferably includes a plurality of transversely alternating, vertically spaced apart flow baffles 66 having apertures therethrough for slidingly supporting the hot tubes 44. The baffles 66 may be generally semicircular and alternately extend from opposite transverse ends of the shell 52 to form a serpentine flow passage 68 for channeling the reactor steam 20 between the hot tubes 44. The shell 52 preferably includes a shell inlet 70 near the top thereof adjacent to the upper containment wall 14, and a shell outlet 72 at the bottom thereof. The reactor steam 20 enters the shell 52 through the inlet 70 and follows the serpentine flow passage 68 transversely back and forth across and between the hot tubes 44 and longitudinally downwardly to the bottom of the shell 52. Accordingly, the reactor steam 20 heats the hot tubes 44 for boiling the working fluid 42 for absorbing heat from the reactor steam 20 to condense the reactor steam 20 and form the reactor condensate 20c which collects at the bottom of the shell 52 and is dischargeable therefrom through the shell outlet 72. The resulting working vapor 42a flows naturally upwardly from the hot tubes 44 and into the cold tubes 46 within the isolation pool 30 wherein the heat contained therein is released into the pool water 32. In order to improve the convective heat transfer capability of the cold tubes 46, they are preferably primarily inclined at the angle A as illustrated in FIG. 2 in order to more readily shed therefrom pool vapor 32a which is in the form of steam bubbles. Since the hot and cold tubes 44 and 46 are preferably arranged in an annular configuration, with the cold tubes 46 being inclined at the angle A, the cold tubes 44 have a bend 74 which is located at progressively increasing distances from the tube sheet upper surface 48b from the inside of the bends 74 to the outside of the bends 74 as shown. As illustrated in more particularity in FIG. 6, a distal end region of one of the cold tubes 46 is illustrated to show the working vapor 42a being channeled upwardly at the inclination angle A within the cold tube 46. The relatively cold pool water 32 cools the cold tube 46 which causes the working vapor 42a to condense in the form of droplets along the inner surface of the cold tube 46 which coalesce to form the working condensate 42b which flows downwardly along the inside of the cold tube 46. The heat liberated from the condensation of the working vapor 42a heats and boils the pool water 32 adjacent to the cold tube 46 for forming the pool vapor 32a in the form of steam bubbles which collect around the outer surface of the cold tube 46. If the cold tubes 46 were oriented completely upright, the pool vapor bubbles 32a would coalesce along the outer surface of the cold tube 46 and form a boundary layer of the pool vapor 32a therearound which would increase in thickness in the vertical direction. Such boundary layer is an insulator which decreases the ability of the cold tubes 46 to dissipate heat. By inclining the cold tubes 46 at the inclination angle A, the natural buoyancy forces on the pool vapor bubbles 32a will cause such bubbles to be shed vertically from the outer surface of the cold tube 46 as they travel upwardly therealong. In this way, the insulating film of the pool vapor 32a is reduced if not eliminated for thusly improving the heat transfer capability of the cold tubes 46. The liberated pool vapor 32a rises upwardly to the surface of the isolation pool 30 as shown in FIG. 1 and is released from the pool 30 through the vent 34 to carry away the heat. In this way, the heat contained in the reactor steam 20 is dissipated into the isolation pool 30 and in turn is dissipated through the vent 34 to the atmosphere. Referring again to FIG. 1, the isolation condenser 36 in accordance with one embodiment is joined directly to the pressure vessel 16. A conventional inlet conduit 76 is disposed in flow communication between the shell inlet 70 and a secondary outlet 78 of the pressure vessel 16 for selectively channeling the reactor steam 20 to the shell 52. The inlet conduit 76 includes a conventional, selectively openable and closeable shutoff inlet valve 80 in series flow therein. In a preferred embodiment, an outlet conduit 82 is disposed in flow communication between the shell outlet 72 and a secondary inlet 84 of the pressure vessel 16 for selectively returning the reactor condensate 20a to the pressure vessel 16. In a preferred embodiment, the outlet conduit 82 includes a conventional, selectively openable and closable shutoff outlet valve 86, and the inlet and outlet conduits 76 and 82 are disposed in parallel flow between the shell 52 and the pressure vessel 16. The inlet and outlet valves 80 and 86 are preferably normally open valves, which may be conventionally spring biased open so that upon failure of power thereto these valves are open for providing passive isolation cooling of the reactor steam 20 by the isolation condenser 36. During normal operation of the reactor core 18, power is conventionally provided to the inlet and outlet valves 80 and 86 so that they are both closed for isolating the condenser 36 from the pressure vessel 16. This is one improvement over a conventional isolation condenser including a conventional heat exchanger which requires normally closed isolation valves which must be closed in the event of a power failure to ensure that any failure within the heat exchanger thereof does not release radioactive steam from the isolation pool thereof to the atmosphere. Since the heat pipes 40 provide a redundant barrier to prevent the radioactive reactor steam 20 from leaking into the isolation pool 30, the inlet and outlet valves 80 and 86 may be normally open for providing a more passive isolation cooling system with reduced risk of radioactivity release to the atmosphere. In an alternate embodiment of the isolation cooling system 10 illustrated in FIG. 1, the secondary inlet 84 and outlet valve 86 may be eliminated, with the outlet conduit 82 being disposed in direct flow communication with the inlet conduit 76 between the inlet valve 80 and the shell inlet 70 as shown in phantom line designated 82a. In this way, the single secondary outlet 78 and inlet valve 80 may be used for controlling operation of the condenser 36, with the reactor steam 20 being channeled upwardly through the inlet line 76 to the shell inlet 70 and the reactor condensate 20c flowing downwardly from the shell outlet 72 and also through the inlet valve 80 and secondary outlet 78 into the pressure vessel 16. The inlet conduit 76 in such an embodiment will channel both the reactor steam 20 in one direction and the reactor condensate 20c in an opposite direction through the same conduit. However, in order to prevent the reactor steam 20 from flowing upstream against the reactor condensate 20c in the outlet conduit 82a, the outlet conduit 82a preferably includes a conventional U-shaped steam trap 82b which may be alternatively known as a manonometer-type seal. The steam trap 82b will fill with the reactor condensate 20c and therefore prevent the reactor steam 20 from flowing upstream therethrough and into the shell 52 through the shell outlet 72. However, the reactor condensate 20c upon filling the steam trap 82b will be allowed to flow therethrough to continue its passage through the outlet conduit 82a and into the pressure vessel 16. In this exemplary embodiment, the isolation condenser 36 is elevated above the reactor core 18 and the reactor water 20a therein so that gravity is used to return the reactor condensate 20c to the pressure vessel 16. Although the heat pipes 40 described above for this preferred embodiment of the present invention utilize gravity to return the working condensate 42b back to the hot tubes 44, the heat pipes 40 in alternate embodiments of the invention could also be conventional capillary-type heat pipes which rely on capillary action of the working fluid 42 instead of gravity for returning the working condensate 42b from the cold tubes 46 to the hot tubes 44. In yet another alternate embodiment, the secondary outlet 78 and inlet valve 80 may be eliminated, with the inlet conduit 76 having an open inlet end 76a as shown in phantom in FIG. 1 disposed in direct communication with the interior of the containment building 12 for directly channelling to the shell inlet 70 any reactor steam 20 which might escape into the building 12 by accident. While there have been described herein what are considered to be preferred embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein, and it is, therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention.
	summary
047822317	claims	1. A method of preparation of .sup.99m Tc elution comprising the steps of, filling a main column composed of a material selected from the group consisting of aluminum, zirconium, quartz, carbon and oxides thereof with a target material comprising at least 10% by weight of molybdenum; plugging the ends of the main column with a porous material; closing the ends of the main column; wrapping the ends of the main column to protect against secondary bacterial contamination; activating the target material to form a .sup.99 Mo containing sorption matrix accompanied simultaneously by radiation sterilization of the main generator column and its contents by exposure to neutron and accompanied gamma radiation in a reactor; opening the ends of the main generator column in sterile environment under aseptic conditions of manipulation; connecting a supply tube to one end of the main column and a discharge tube to the other end in a sterile manner; placing the main column, supply tube, and discharge tube in a transport container composed of a material selected from the group consisting of lead or depleted uranium; placing the transport container in a laboratory container, the laboratory container also housing an elution vessel, a protective column, and at least one eluate collection bottle; connecting the supply tube to an elution vessel in a sterile manner, the elution vessel containing an elution solution; connecting the discharge tube to one end of a protective column in a sterile manner, the other end having a piercing head; piercing the seal of an evacuated eluate collection bottle with the piercing head; drawing the eluation solution through the supply tube, main column containing the sorption matrix, discharge tube, and protective column, and into the eluate collection bottle, the eluate containing .sup.99m Tc. 2. A method as in claim 1 wherein the ratio of the diameter of the main column to its height is 1:2-5; the target material is selected from the group consisting of molybdates and polymolybdates of titanium and zirconium having a molybdenum content of from 20 to 40% by weight; the porous plug is composed of a material selected from the group consisting of aluminum, zirconium, quartz, carbon, oxides and composites thereof, and felt, the elution solution is a 0.9% solution of NaCl by weight; the protective column contains a sorbent selected from the group consisting of zirconium oxide and aluminum oxide; and the transport container is a material selected from the group consisting of lead and depleted uranium. 3. A method as in claim 1 additionally comprising the steps of placing the transport container in a protective container; shipping the protective container to the user, and removing the transport container from the protective container prior to the step of placing the transport container in the laboratory container. 4. A method as in claim 2 additionally comprising the steps of placing the transport container in a protective container; shipping the protective container to the user, and removing the transport container from the protective container prior to the step of placing the transport container in the laboratory container. 5. A method as in claim 1, wherein the target material is selected from the group consisting of molybdates and polymolybdates of zirconium titanium and other elements, the specific activity thereof, expressed in Bq/g of the corresponding element 25 hours after reactor irradiation end, is lower than twice the specific activity of .sup.99 Mo reached irradiating under the same conditions molybdenum in its natural isotopic mixture; the content of molybdenum in the target plugs, covers and other parts of the main generator column are made from elements and their oxides, the specific activity thereof, 24 hours after reactor irradiation end, is lower than twice the specific activity of .sup.99 Mo reached by irradiating under the same conditions molybdenum in its natural isotopic abundance, the specific activity is evaluated by Bq/g of the corresponding element; wherein the elements used are selected from the group consisting of zirconium, titanium, aluminum, carbon, silicon and their oxides; the porous plugs are made from the above mentioned materials formed into fibers, composites, felt or wool. 6. A method as in claim 5 additionally comprising the steps of placing the transport container in a protective container; shipping the protective container to the user, and removing the transport container from the protective container prior to the step of placing the transport container in the laboratory container.
	abstract	A reactor water radioactivity concentration of a nuclear power plant can be predicted with high accuracy. First, a plant state quantity prediction value is calculated by using a physical model that describes plant state quantities of the power plant including a flow rate of feedwater and a metal corrosion product concentration in feedwater of the reactor water is calculated. Next, data for supervised learning is created, and the data for supervised learning includes the previously calculated plant state quantity prediction value and a plant state quantity such as the flow rate of feedwater, the metal corrosion product concentration in feedwater, a metal corrosion product concentration in reactor water, and a radioactive metal corrosion concentration of the reactor water in the reactor as input data and includes a radioactive metal corrosion concentration in the reactor water which is an actual measured value as output data, and a predictive model is trained.
	abstract	In a head-end process for the reprocessing of reactor core material with embedded fuel particles, reactor core material is arranged in a reactor containing a fluid. The reactor comprises a voltage discharge installation in the fluid. Voltage discharges are applied through the fluid for fragmenting the fuel particles into fragmentation products and the fragmentation products are segregated.
	claims	1. A shock-absorbing device for a fuel assembly including a plurality of fuel rods, the shock-absorbing device comprising:a first nozzle and a second nozzle including one surfaces, respectively, by which the plurality of fuel rods are sandwiched, the first and second nozzles including other surfaces having a plurality of legs for defining first and second depressions, respectively;a nozzle support fitted to a center portion of the first depression of the first nozzle, the nozzle support being comprised of iron, aluminum alloy containing boron)(B10), stainless steel, lead, or concrete so that radiation from the fuel assembly is shielded; anda buffer combined with the nozzle support, the buffer having stiffness in a longitudinal direction of the fuel rods being equal to or less than that of the nozzle support, whereinthe nozzle support and the buffer are arranged in sequence along the longitudinal direction of the fuel rods as separating from the depressions and whereinthe buffer is either one of the followings (a) to (g):(a) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member;(b) a buffer including a bottom plate and a plurality of plate materials fitted to the bottom plate;(c) a buffer including a bottom plate and a plurality of rod members arranged with an axial direction being parallel to the longitudinal direction of the fuel rods;(d) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member, the casing being coupled with a pipe for housing the plurality of fuel rods by a coupling member (33);(e) a buffer including a first buffer that is provided with a depression and contacts the plurality of legs and a second buffer that is provided on the depression and contacts the nozzle support;(f) a buffer including a first buffer that contacts the plurality of legs and a second buffer that is provided with a salient and contacts the nozzle support at the salient, the first buffer having stiffness in a compression direction lower than that of the second buffer in the compression direction;(g) a buffer that has a depression and contacts the nozzle support at the depression, the buffer contacting the plurality of legs. 2. The shock-absorbing device for a fuel assembly according to claim 1, whereinthe first nozzle is arranged on a bottom side of a fuel assembly housing container for transporting the fuel assembly. 3. The shock-absorbing device for a fuel assembly according to claim 1, whereinthe second nozzle is arranged at an opening side of a fuel assembly housing container for transporting the fuel assembly. 4. A fuel assembly housing container comprising:a body that is a container with a bottom and houses a fuel assembly in an internal space thereof; andthe shock-absorbing device for a fuel assembly according to claim 1, which is arranged at least on a bottom of the body. 5. The fuel assembly housing container according to claim 4, wherein the shock-absorbing device for a fuel assembly according to claim 1 is arranged on a lid fitted to an opening of the internal space. 6. A shock-absorbing device for a fuel assembly including a plurality of fuel rods, the shock-absorbing device comprising:a first nozzle and a second nozzle including one surfaces, respectively, by which the plurality of fuel rods are sandwiched, the first and second nozzles including other surfaces having a plurality of legs for defining first and second depressions, respectively;a nozzle support fitted to a center portion of the second depression of the second nozzle, the nozzle support being comprised of iron, aluminum alloy containing boron)(B10), stainless steel, lead, or concrete so that radiation from the fuel assembly is shielded; anda buffer combined with the nozzle support, the buffer having stiffness combined with the first nozzle and the second nozzle in a longitudinal direction of the fuel rods being equal to or less than that of the nozzle support, whereinthe nozzle support and the buffer are arranged in sequence along the longitudinal direction of the fuel rods as separating from the depressions and whereinthe buffer is either one of the followings (a) to (g):(a) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member;(b) a buffer including a bottom plate and a plurality of plate materials fitted to the bottom plate;(c) a buffer including a bottom plate and a plurality of rod members arranged with an axial direction being parallel to the longitudinal direction of the fuel rods;(d) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member (11I), the casing being coupled with a pipe for housing the plurality of fuel rods by a coupling member;(e) a buffer including a first buffer that is provided with a depression and contacts the plurality of legs and a second buffer that is provided on the depression and contacts the nozzle support;(f) a buffer including a first buffer that contacts the plurality of legs and a second buffer that is provided with a salient and contacts the nozzle support at the salient, the first buffer having stiffness in a compression direction lower than that of the second buffer in the compression direction;(g) a buffer that has a depression and contacts the nozzle support at the depression, the buffer contacting the plurality of legs. 7. A shock-absorbing device for a fuel assembly including a plurality of fuel rods, the shock-absorbing device comprising:a first nozzle and a second nozzle, the first and second nozzles including one surfaces, respectively, by which the plurality of fuel rods are sandwiched and the first and second nozzles including other surfaces having a plurality of legs for defining first and second depressions, respectively;first and second nozzle supports fitted to a center portion of the first depression of the first nozzle and a center portion of the second depression of the second nozzle, respectively, the first and second nozzle supports being comprised of iron, aluminum alloy containing boron (B10), stainless steel, lead, or concrete so that radiation from the fuel assembly is shielded; andfirst and second buffers combined with the first and second nozzle supports, respectively, the first and second buffers having stiffness in a longitudinal direction of the fuel rods being equal to or less than that of the first and second nozzle supports, respectively, whereinthe first nozzle support and the first buffer are arranged in sequence along the longitudinal direction of the fuel rods as separating from the first depression and the second nozzle support and the second buffer are arranged in sequence along the longitudinal direction of the fuel rods as separating from the second depression and whereinthe first and second buffers are selected from either one of the followings (a) to (g):(a) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member;(b) a buffer including a bottom plate and a plurality of plate materials fitted to the bottom plate (11B);(c) a buffer including a bottom plate and a plurality of rod members arranged with an axial direction being parallel to the longitudinal direction of the fuel rods;(d) a buffer including a buffer member including a hydrogen-containing resin so as to shield neutron and a casing holding and surrounding the buffer member, the casing being coupled with a pipe for housing the plurality of fuel rods by a coupling member;(e) a buffer including a first buffer that is provided with a depression and contacts the plurality of legs and a second buffer that is provided on the depression and contacts the nozzle support;(f) a buffer including a first buffer that contacts the plurality of legs and a second buffer that is provided with a salient and contacts the nozzle support at the salient, the first buffer having stiffness in a compression direction lower than that of the second buffer in the compression direction;(g) a buffer that has a depression and contacts the nozzle support at the depression, the buffer contacting the plurality of legs. 8. The shock-absorbing device for a fuel assembly according to claim 7, whereinthe first nozzle is arranged on a bottom side of a fuel assembly housing container for transporting the fuel assembly. 9. The shock-absorbing device for a fuel assembly according to claim 7, whereinthe second nozzle is arranged at an opening side of a fuel assembly housing container for transporting the fuel assembly. 10. A fuel assembly housing container comprising:a body that is a container with a bottom and houses a fuel assembly in an internal space thereof; andthe shock-absorbing device for a fuel assembly according to claim 7, which is arranged at least on a bottom of the body. 11. The fuel assembly housing container according to claim 10, wherein the shock-absorbing device for a fuel assembly is arranged on a lid fitted to an opening of the internal space.
	abstract	The present invention proposes a sub-wavelength luminescence sensor, such as e.g. a luminescence biosensor or a luminescence chemical sensor, comprising at least two wire grids (1, 2) positioned perpendicular with respect to each other. The luminescence sensor, in which the excitation radiation is efficiently used and the luminescence radiation is efficiently detected, has an improved signal-to-noise ratio and a separated excitation and luminescence radiation.
052710491	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is generally related to nuclear fuel assemblies and, in particular to an apparatus and method for loading fuel rods into interior grid cells of the fuel assembly. 2. General Background Grids used in commercial nuclear fuel assemblies are fabricated with stops that grip the fuel rods in place when the fuel assembly is in the as-built condition. The stops on two adjacent cell walls are hard stops, with a fixed location, and the other two cell walls have spring loaded soft stops. During fuel assembly fabrication it is desirable to have the soft stops withdrawn away from the centerline of each grid cell to allow free passage of the fuel rod into and through the grid. Keying of the stops to cause them to withdraw from the centerline of their grids is typically performed using a rectangular wire that is inserted into and through the windows of the grid. The wire key extends through the full width of the grid and is rotated so that the thickest cross section of the key wedges the strip section backward and thus withdraws the stop. The key is machined with cutouts to preclude interference with the fuel rods when in the rotated position. Several interior grid cells, however, can not be keyed using the rectangular keys. This is due to interference with previously installed guide thimbles. Guide thimbles that have ferrules attached to restrain the grid must be installed prior to insertion of the fuel rods. The guide thimbles have a larger diameter than the fuel rods and the rectangular keys do not have clearance to get past the thimbles. As a result, several fuel rods must be installed into unkeyed grid cells. A lubricant is used to minimize damage to the fuel rods, but the lubricant is difficult to remove from the fuel rods after assembly. Patents directed to keying of grid cells that applicants are aware of include the following. U.S. Pat. No. 3,933,583 discloses rectangular wire keys used for deflecting stops in the grid. U.S. Pat. No. 4,651,403 discloses a pair of comb devices that are utilized to depress springs within the grid cells for loading of fuel rods. U.S. Pat. No. 5,068,081 discloses the consecutive use of two separate members in the grid wherein the first member is removed after the second member is inserted and the fuel rods are then loaded into the grid. U.S. Pat. No. 5,124,116 discloses a grid key for keying exterior grid cells only. The known art does not address the need for a grid key that may be used on interior grid cells when the soft stops can not be retracted from the adjacent cell due to interference from associated equipment such as a guide thimble. SUMMARY OF THE INVENTION The present invention addresses the above problem in a straightforward manner. What is provided is a grid key for keying individual interior grid cells. A main body portion is bent at approximately a 90 degree angle near its middle. One end of the main body portion is provided with two tabs that each extend outward in opposite directions along a portion of the length of the main body portion. The tabs are flush with one side of the main body portion and taper inwardly at approximately a 45 degree angle toward the rear of the main body portion on another side. Keying of the grid is accomplished by inserting the end with the tabs into the corner of the cell so that the portion of the key beyond the 90 degree bend above the cell extends away from the cell at a 45 degree angle. An installation tool is used to push the tab end of the key between the soft stops in the corner and wedge it into place. This retracts the soft stops. The fuel rod may then be loaded and the key removed afterward.
	claims	1. A collimator arrangement in a digital X-ray imaging apparatus comprising at least one X-ray source and a registering means, said collimator arrangement being provided for varying an exposure area of said registering means to X-ray radiation from said X-ray source, said varying being dependent on a tilt angle associated with the registering means, said collimator arrangement comprising at least two substantially similar collimator parts, namely a first part and second part, each part comprising a carrier, each being provided with similar slot configurations arranged along a longitudinal axis of the said carrier, wherein said first collimator part is arranged on one surface of said second collimator part and tat said substantially similar collimator parts are arranged to slide relative each other in a transversal direction. 2. The arrangement according to claim 1 , wherein said registering means is one of a semiconductor-based detector, a gas-based detector or an X-ray sensitive film. claim 1 3. A method for providing a variable exposure of registering means to X-ray radiation from an X-ray source within an X-ray imaging apparatus, sad apparatus including a collimator arrangement comprising at least two substantially similar collimator parts, of which each one of a first part and second part includes a carrier provided with similar slot configurations, the method comprising the step of: varying the collimator arrangement, where said varying is dependent on a tilt angle associated with the registering means, wherein the steps of varying the collimator arrangement further comprises: arranging said first collimator part on one surface of said second collimator part; and sliding said substantially similar collimator parts relative each other in a transversal direction, enabling adjusting a spatial resolution in a dimension orthogonal to said slots.
044118619	description	Referring now to the drawing and first, particularly, to FIG. 1 thereof, there is shown a fuel rod cladding tube 2 in an end view before the method according to the invention is performed. In the interior of the tube 2, a pressure P.sub.o prevails, which also corresponds to external pressure. FIG. 2 shows that through application of a high internal pressure P.sub.1 as well as of a temperature of 300.degree. to 500.degree. C., an enlargement or widening of the cladding tubes has occurred. In this expanded cladding tube 2, the deformation of which has been effected, while yet in the elastic range or region, nearly to the yield point, a protective layer 3 is formed by an introduced medium. This condition is shown in FIG. 3. After this protective layer 3 has been formed, and pressure and temperature have been reduced, the fuel rod cladding tube 2 returns to its original shape according to FIG. 4, the protective layer 3' formed in the interior thereof being compressed i.e. being stressed in compression. The diameter increase shown in the figure is, obviously, not to scale, but rather, has been greatly exaggerated in order to illustrate the principle of the invention. FIG. 5 illustrates two possibilities for performing the method practically. The fuel rod cladding tubes 1 are tightly welded at the one end thereof to a conventional end plug 4. The tubes 1, at the other end thereof, are welded to a provisional or temporary end plug 5 which is connected to a pressurized-gas source 52 through a line 51. To heat such a fuel rod uniformly, it is placed in a furnace 8, indicated only diagrammatically in FIG. 5, for carrying out the method. Another heat source, such as inductive heating, could obviously also be used for this purpose. To apply the required high internal pressure for producing the elastic expansion which, for conventional dimensions of a fuel rod cladding tube, is more than 100 bar, pressure gas, such as nitrogen, for example, is delivered through the line 51. This gas additionally contains a given amount of the substance forming the protective layer, such as oxygen, for example. With this entrained oxygen, the inside wall surface of the cladding tube is oxidized and ZrO.sub.2 is formed. The same effect is also obtained through the application of high-pressure steam. The mechanism for forming the protective layer corresponds to that known heretofore from the technology of the autoclaving of zirconium cladding tubes. In the latter process, however, the cladding tube per se is not stressed mechanically, so that the protective layers formed thereon show no internal residual stresses. Another elegant procedure for performing the method of the invention is shown in FIG. 5 in regard to the lower cladding tube 1 illustrated therein. The latter tube 1 is disposed in the same furnace 8 and is closed by a provisional or temporary end plug 6. The end plug 6 is absolutely tight, no connection being provided to any source of pressurized gas. Before the temporary plug 6 was inserted, however, a given amount of water (note the drop 7) was introduced into the lower cladding tube 1 shown in FIG. 5. The amount of water in the drop 7 was determined as the amount which will produce the internal pressure required for the elastic deformation at the temperature provided by the furnace. Instead of the drop of water 7, a corresponding amount of hydrogen peroxide could also be used. When the latter evaporates, atomic oxygen is produced which causes the inner wall surface of the cladding tube to oxidize more rapidly than has been possible by any of the methods mentioned hereinbefore. Instead of liquids, other gas-yielding or generating substances can, of course, also be introduced, it being important that these substances be able to be reliably metered. The excellent protective action against stress-crack corrosion achieved by this method invention is explainable not only by the compressive-stress layer but also by the procedure due to which the protective layer is applied to the widened or expanded cladding tube. This protective layer is formed also, for example, in gaps between the end plugs and the open cladding tubes, as well as at the boundary of the welded seam connecting them one to the other. The same thing applied as well to surface defects which can stem from the process of manufacturing the open-ended cladding tubes per se. As compared to the normal autoclave technology, a complete coating or layer is thus produced which extends into the microscopic range and has a thickness of up to 5 .mu.m advantageiously. A further advantage connected with this method invention ought not to be omitted. This is that while this method is being performed, a possibility is simultaneously provided for checking the tightness of the welding seam between the end plug 4 and the previously open-ended cladding tube 2. This can be accomplished if the interior of the furnace 8 is tightly closed off, and the pressure therein is monitored. It should also be noted that this method according to the invention extends not only to the formation of oxide layers, but that, carbide and silicide layers and the like could also be utilized to achieve stress-crack corrosion resistance. The choice of the most suitable protective layers depends upon the selection of the cladding tube material, which may well always be a zirconium alloy, as well as upon the specification of the nuclear fuel. It should be further noted that it is also possible to apply this method invention to previously completed nuclear fuel rods i.e. fuel rods already containing their nuclear fuel charge. In that case, the oxidant, for example, must be introduced before the open-ended cladding tube is finally closed off. This oxidant can be of such composition then as to provide simultaneously for the so-called initial internal pressure of the nuclear reactor fuel rod during the operation of the fuel rod.
040594840	claims	1. A hybrid fuel assembly to reduce the maximum and average linear heat generation rates for use in a nuclear reactor having a plurality of control rods comprising a plurality of elongated fuel rods disposed in spaced parallel array, said fuel rods including a first plurality of said fuel rods having a first diameter and a second plurality of said fuel rods having a second diameter greater than said first diameter, said first plurality of fuel rods includes a first fuel enrichment and said second plurality of fuel rods includes a second fuel enrichment different from said first fuel enrichment, said second plurality of fuel rods being divided into clusters of fuel rods forming islands, said islands including guide tubes having diameters substantially the same as said second plurality of fuel rods, one guide tube corresponding to each of said control rods, said islands located within said assembly so that said guide tubes may receive all of said control rods, said islands being symmetrically located relative to the intersecting diagonal centerlines of said fuel assembly. 2. The hybrid fuel assembly of claim 1 wherein said first plurality of fuel rods are located about the periphery of said fuel assembly. 3. The hybrid fuel assembly of claim 1 wherein said second plurality of fuel rods are located internally of said fuel assembly. 4. The hybrid fuel assembly of claim 1, wherein said second plurality of fuel rods are located internally of said fuel assembly in clusters of fuel rods each of which comprises an island wherein said fuel rods have a pitch different from that of said first plurality of fuel rods. 5. The hybrid fuel assembly of claim 4 wherein said fuel assembly comprises four of said islands, each of said islands being symmetrically located relative to the intersecting diagonal centerlines of said fuel assembly. 6. The hybrid fuel assembly of claim 1 wherein said fuel assembly comprises a plurality of islands symmetrically located about the intersecting diagonal centerlines of said fuel assembly, each of said islands comprising said second plurality of fuel rods, said first plurality of fuel rods having a first pitch corresponding to that for said fuel assembly and said second plurality of fuel rods having a second pitch different from said first pitch. 7. The hybrid fuel assembly of claim 1 wherein said fuel assembly includes a plurality of islands comprising a predetermined number of said second plurality of fuel rods, and each of said islands replacing a predetermined number of said first plurality of fuel rods which is greater than the number of fuel rods of said second plurality contained in each of said islands. 8. The hybrid fuel assembly of claim 1 wherein said fuel assembly comprises a plurality of islands of said second plurality of fuel rods, said second plurality of fuel rods having a larger diameter than that of said first plurality of fuel rods, said fuel assembly having maximum power peaking based on volumetric heat generation rate in the ones of said first plurality of fuel rods surrounding each of said islands. 9. The hybrid fuel assembly of claim 1 wherein said second plurality of fuel rods has a diameter greater than that of said first plurality of fuel rods. 10. The hybrid fuel assembly of claim 1 wherein said fuel assembly comprises a plurality of modules wherein each of said modules comprises an island having said second plurality of fuel rods maintained at a pitch different from that of said first plurality of fuel rods, each of said islands being located in the vicinity of said control means for said first plurality of fuel rods, thereby reducing the linear heat generation rates of said second plurality of fuel rods to that normally associated with said first plurality of fuel rods.
046718982	claims	1. A process for treatment of a spent, radioactive, organic ion exchange resin to reduce the volume thereof and to obtain a stable end product comprising mixing the ion exchange resin with a salt, which liberates radioactive substances from said ion exchange resin, as well as with an inorganic sorbent for the radioactive substances thus liberated, then drying and incinerating said mixture and solidifying the residue from the incineration in cement. 2. A process according to claim 1 wherein the salt is added in such a quantity that the ion exchange resin will be essentially saturated. 3. A process according to claim 1 wherein the salt is a salt of aluminum or calcium. 4. A process according to claim 1 wherein the salt is a salt of phosphoric acid, citric acid, tartaric acid, oxalic acid, formic acid or proponic acid. 5. A process according to claim 1 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural or synthetic zeolite, or a mixture of two or more of these sorbents. 6. A process according to claim 1 wherein the dried mixture is incinerated at a temperature of 500.degree.-900.degree. C. 7. A process according to claim 6 wherein the dried mixture is incinerated in oxygen-enriched air. 8. A process according to claim 2 wherein the salt is a salt of aluminum or calcium. 9. A process according to claim 2 wherein the salt is a salt of phosphoric acid, citric acid, tartaric acid, oxalic acid, formic acid or propionic acid. 10. A process according to claim 2 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural synthetic zeolite, or a mixture of two or more of these sorbents. 11. A process according to claim 3 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural synthetic zeolite, or a mixture of two or more of these sorbents. 12. A process according to claim 4 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural synthetic zeolite, or a mixture of two or more of these sorbents. 13. A process according to claim 8 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural synthetic zeolite, or a mixture of two or more of these sorbents. 14. A process according to claim 9 wherein the sorbent is a titanate or titanium hydroxide, a zirconate or a zirconium hydroxide or zirconium phosphate, an aluminate or an aluminum hydroxide, an alumino silicate such as bentonite or a natural synthetic zeolite, or a mixture of two or more of these sorbents. 15. A process according to claim 2 wherein the dried mixture is incinerated at a temperature of 500.degree.-900.degree. C. 16. A process according to claim 3 wherein the dried mixture is incinerated at a temperature of 500.degree.-900.degree. C. 17. A process according to claim 4 wherein the dried mixture is incinerated at a temperature of 500.degree.-900.degree. C. 18. A process according to claim 5 wherein the dried mixture is incinerated at a temperature of 500.degree.-900.degree. C. 19. A process according to claim 15, wherein the dried mixture is incinerated in oxygen-enriched air.
06295329&	claims	1. A reactor-internal equipment handling apparatus comprising: control rod holding means for releasably holding a control rod which is loaded in a reactor vessel; fuel support/control rod guide tube holding means for releasably holding both a fuel support, which supports a bottom end of a fuel assembly, and a control rod guide tube, on which the fuel support is placed at a top end; a main body frame to which both the control rod holding means and the fuel support/control rod guide tube holding means are fitted and is adapted to be hung down inside the reactor vessel; a holding state detecting mechanism for detecting both a holding state of the control rod holding means about the control rod and a holding state of the fuel support/control rod guide tube holding means about the fuel support and the control rod guide tube; and a positioning state detecting mechanism for detecting a positioning state of the main body frame in the reactor vessel. wherein an amount of motion of the orifice engaging member is adjusted by changing the operating stroke of the orifice engaging member linking mechanism by the stroke varying mechanism such that the orifice engaging member engages only the edge portion of the orifice formed in the fuel support. wherein the orifice engaging member linking mechanism is constructed to disable a motion of the orifice engaging member in a situation that the stepped portion of the orifice engaging member comes into contact with the edge portion of the orifice. wherein the handle engaging member is formed of a hook member, and an own weight of the control rod is applied to hold an engaged state of the hoisting handle by the handle engaging member in a situation that the control rod holding means hoists the control rod via the handle engaging member. the positioning state detecting mechanism has a positioning state confirming indicator lamp whose lighting state is changed depending upon a change in the positioning state of the main body frame in the reactor vessel. control rod holding means for releasably holding a control rod which is loaded in a reactor vessel; fuel support/control rod guide tube holding means for releasably holding both a fuel support, which supports a bottom end of a fuel assembly, and a control rod guide tube, on which the fuel support is placed at a top end; and a main body frame to which both the control rod holding means and the fuel support/control rod guide tube holding means are fitted and is adapted to be hung down inside the reactor vessel, wherein the fuel support/control rod guide tube holding means includes an orifice engaging member which is adapted to engage edge portions of orifices formed in the fuel support and a top portion of the control rod guide tube, an orifice engaging member linking mechanism for manipulating the orifice engaging member, and orifice engaging member driving means for driving the orifice engaging member linking mechanism, and wherein the orifice engaging member linking mechanism comprises a mechanical lock which prevents the orifice engaging member from moving after the orifice engaging member engages the edge portions of the orifices formed in the fuel support and the control rod guide tube. wherein the handle engaging member includes a hook member, and wherein a weight of the control rod maintains an engaged state between the hoisting handle by the handle engaging member in a situation that the control rod holding means hoists the control rod via the handle engaging member. wherein an amount of motion of the orifice engaging member is adjusted by changing the operating stroke of the orifice engaging member linking mechanism by the stroke varying mechanism such that the orifice engaging member engages only the edge portion of the orifice formed in the fuel support. wherein the orifice engaging member linking mechanism makes the mechanical lock in a situation that the stepped portion of the orifice engaging member comes into contact with the edge portion of the orifice. a holding state detecting mechanism for detecting both a holding state of the control rod holding means about the control rod and a holding state of the fuel support/control rod guide tube holding means about the fuel support and the control rod guide tube; and a positioning state detecting mechanism for detecting a positioning state of the main body frame in the reactor vessel. the positioning state detecting mechanism has a positioning state confirming indicator lamp an illumination of which changes depending upon a change in the positioning state of the main body frame in the reactor vessel. 2. A reactor-internal equipment handling apparatus according to claim 1, wherein the fuel support/control rod guide tube holding means includes an orifice engaging member which is adapted to engage edge portions of orifices formed in the fuel support and the control rod guide tube, an orifice engaging member linking mechanism for manipulating the orifice engaging member, and orifice engaging member driving means for driving the orifice engaging member linking mechanism. 3. A reactor-internal equipment handling apparatus according to claim 2, further comprising a stroke varying mechanism for varying an operating stroke of the orifice engaging member linking mechanism; 4. A reactor-internal equipment handling apparatus according to claim 2, wherein the orifice engaging member has stepped portions which come into contact with the edge portions of the orifices formed in the fuel support and the control rod guide tube, and 5. A reactor-internal equipment handling apparatus according to claim 1, wherein the control rod holding means has a handle engaging member which is swingable and holds a hoisting handle provided on a top end of the control rod, and handle engaging member driving means for driving the handle engaging member to swing, and 6. A reactor-internal equipment handling apparatus according to claim 1, wherein the control rod holding means and the fuel support/control rod guide tube holding means are fitted to the main body frame such that these means can be relatively displaced mutually along a longitudinal direction of the control rod, and both the fuel support and the control rod guide tube are hoisted after the control rod is slightly hoisted. 7. A reactor-internal equipment handling apparatus according to claim 1, wherein the holding state detecting mechanism has a holding state confirming indicator lamp whose lighting state is changed depending upon a change in the holding states of the control rod holding means and the fuel support/control rod guide tube holding means, and 8. A reactor-internal equipment handling apparatus according to claim 1, wherein the positioning state detecting mechanism further includes a motion limiting mechanism for limiting a motion of the fuel support/control rod guide tube holding means when the main body frame is not properly placed at a predetermined position in the reactor vessel. 9. A reactor-internal equipment handling apparatus according to claim 8, further comprising: a motion limiting mechanism locking device for making the motion limiting mechanism inoperative temporarily. 10. A reactor-internal equipment handling apparatus comprising: 11. A reactor-internal equipment handling apparatus according to claim 10, wherein the control rod holding means has a handle engaging member which is swingable and holds a hoisting handle provided on a top end of the control rod, and handle engaging member driving means for driving the handle engaging member to swing, 12. A reactor-internal equipment handling apparatus according to claim 10, wherein the control rod holding means and the fuel support/control rod guide tube holding means are fitted to the main body frame such so as to be relatively displaced mutually along a longitudinal direction of the control rod, and so that both the fuel support and the control rod guide tube are hoisted after the control rod is slightly hoisted. 13. A reactor-internal equipment handling apparatus according to claim 10, wherein the orifice engaging member linking mechanism is so constituted that a distal end of the orifice engaging member protrudes outwardly from the orifices when the fuel support/control rod guide tube holding means changes from a non-holding state to a holding state, whereby the orifice engaging member establishes the mechanical lock which prevents the orifice engaging member from moving after the orifice engaging member engages the edge portions of the orifices formed in the fuel support and the control rod guide tube. 14. A reactor-internal equipment handling apparatus according to claim 13, further comprising a stroke varying mechanism for varying an operating stroke of the orifice engaging member linking mechanism; and 15. A reactor-internal equipment handling apparatus according to claim 13, wherein the orifice engaging member has stepped portions which come into contact with the edge portions of the orifices formed in the fuel support and the control rod guide tube, and 16. A reactor-internal equipment handling apparatus according to claim 10, further comprising: 17. A reactor-internal equipment handling apparatus according to claim 16, wherein the holding state detecting mechanism has a holding state confirming indicator lamp an illumination of which changes depending upon a change in the holding states of the control rod holding means and the fuel support/control rod guide tube holding means, and 18. A reactor-internal equipment handling apparatus according to claim 16, wherein the positioning state detecting mechanism further includes a motion limiting mechanism for limiting a motion of the fuel support/control rod guide tube holding means when a position of the main body frame is not coincident with a predetermined position in the reactor vessel. 19. A reactor-internal equipment handling apparatus according to claim 18, further comprising: a motion limiting mechanism locking device for temporarily rendering the motion limiting mechanism inoperative.
	abstract	When generating a 3D image of a subject or patient, a cone beam X-ray source (20a, 20b) is mounted to a rotatable gantry (14) opposite an offset flat panel X-ray detector (22a, 22b). A wedge-shaped attenuation filter (24a, 24b) of suitable material (e.g., aluminum or the like) is adjustably positioned in the cone beam to selectively attenuate the beam as a function of the shape, size, and density of a volume of interest (18) through which X-rays pass in order to maintain X-ray intensity or gain at a relatively constant level within a range of acceptable levels.
047388200	description	DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to several present preferred embodiments of the invention, an example of which is illustrated in the accompanying drawings. In the drawings, like reference characters designate like or corresponding parts throughout the several views. In FIG. 1, a (typically 13.5 foot long) nuclear fuel assembly 10 is shown in vertically foreshortened form. The fuel assembly 10 is the type used in a pressurized water reactor (PWR) and basically includes a bottom (or lower) nozzle 13 for supporting the assembly on the lower core plate (not shown) in the core region of a nuclear reactor (not shown), and a number (typically 24) of longitudinally extending (typically 12 foot long) guide thimbles 14 which project upwardly from the bottom (or lower) nozzle 12. The fuel assembly 10 further includes a plurality of transverse grids 16 axially spaced along the guide thimbles 14 and an organized array of elongated fuel rods 18 transversely spaced and supported by the grids 16. Also the assembly has a top nozzle 20 attached to the upper ends of the guide thimbles 14. The lower ends of the guide thimbles 14 are attached to the adaptor plate 22 of the bottom (or lower) nozzle 12. In this region, each guide thimble 14 typically is surrounded by a grid sleeve (not shown). With such an arrangement of parts, the fuel assembly 10 forms an integral unit capable of being conventionally handled without damaging the assembly parts. As mentioned above, the fuel rods 18 in the fuel assembly 10 are held in spaced relationship with one another by the grids 16 spaced along the fuel assembly length. Typically each fuel rod 18 contains nuclear fuel pellets of uranium dioxide (not shown). A liquid moderator/coolant, such as water or water containing boron, is pumped upwardly through the guide thimbles 14 and along the fuel rods 18 of the fuel assembly 10 in order to extract heat generated therein for the production of useful work. To control the fission process, a number of control rods (not shown) are reciprocally movable in the guide thimbles 14 located at predetermined positions in the fuel assembly 10. In FIG. 1, a nuclear reactor fuel assembly bottom nozzle to guide thimble attachment system is shown for a first embodiment of the apparatus of the invention, in which a bottom-insertable, two-headed bolt 24 is used for the attachment. By "bottom-insertable" is meant insertable from the bottom of the fuel assembly. The bottom nozzle adaptor plate 22a has a bore 26. The lower end of the guid thimble 14 has an attached (e.g. welded) bottom end plug 28. The bottom end plug 28 has a threaded axial passageway 30 which is aligned with the bottom nozzle adaptor plate's bore 26. The two-headed bolt 24, seen in FIGS. 2 and 3, has a longitudinal flow hole 32 to allow passage of coolant. The shank portion 34 has a threaded section 36. The first head 38 is sized to block passage through the bore 26, while the second head 40 is sized to allow passage through the bore 26 and the passageway 30. The two-headed bolt 24 is placed in the bore 26 and threadably inserted in the passageway 30. The first head 38 is proximate the bottom nozzle adaptor plate 22a while the second head 40 is proximate the guide thimble bottom end plug 28. By that is meant the second head 40 faces in the direction of the top nozzle 20. Typically, the two-headed bolt is installed at the time of fuel assembly original manufacture. The fuel assembly skeleton typically is assembled on its side at the fuel plant. Since the fuel assembly has not been irradiated yet in a nuclear reactor, there is no need to do this assembly work under water, and there is no problem gaining access to the bottom nozzle attachment area of the fuel assembly. The first head can be any standard bolt head, but a preferred first head 38 has a face 42 that includes a polygonal-shaped recess 44. In an exemplary arrangement, the bore 26 includes a countersunk bore portion 46 which surrounds the first head 38 and which has a detent 48 into which the first head 38 is crimp-locked to prevent loosening. The second head can be any standard bolt head, but a preferred second head 40 has a plurality of longitudinally-extending, peripheral, generally flat surfaces 50. In this case the second head would extend above the bottom end plug far enough for a socket wrench (for example), acting from above, to unthread the two-headed bolt. It is noted that if the second head 40 had a wrenching feature that was a polygonal-shaped recess, then it would not have to extend above the bottom end plug to be unthreaded by an allen wrench (for example) acting from above. The two-headed bolt 24 arrangement allows for bottom insertion during manufacture to attach the bottom (or lower) nozzle 12 to the guide thimbles 14. Presently, single-headed bolts or screws are bottom inserted for this attachment. The two-headed bolt 24 arrangement allows for top unthreading to detach the bottom (or lower) nozzle 12 from the guide thimbles 14 without having to invert the fuel assembly 10. Presently, the fuel assembly must be inverted for this detachment. Such disassembly work on an irradiated fuel assembly must be done under water. The bottom nozzle of an irradiated fuel assembly may be removed as one of the steps during a fuel assembly reconstitution procedure or during a spent fuel rod consolidation procedure. Hence, in these cases, the two-headed bolt 24 arrangement allows for fuel assembly reconstitution or spent fuel rod consolidation without inverting the fuel assembly. To remove the bottom nozzle 12 from the guide thimbles 14 of the fuel assembly 10, the fuel assembly 10 is placed in a generally upright position, or at least with its top nozzle 20 higher than its bottom nozzle 12. Then, a long-handled wrench is inserted into each guide thimble 14, from the top nozzle 20 towards the bottom nozzle 12, and into engagement with the second head 40 of the two-headed bolt 24. It is noted that the wrench can enter the guide thimble as easily as can a control rod and removal of the top nozzle is not required. The wrench is used to overcome any crimp-lock and unthread the two-headed bolt 24 which will fall away. When all the two-headed bolts are thus removed, the bottom nozzle 12 will fall away. Typically, such work occurs on an upright fuel assembly suspended underwater in the spent fuel pit of the nuclear reactor, with a laterally-movable tray or bucket placed beneath the fuel assembly to collect the deattached two-headed bolts 24 and the detached bottom (or lower) nozzle 12. The top nozzle 20 is removed by methods known to those skilled in the art, such methods forming no part of this invention. Typically, the spent fuel rods 18 are pushed out the bottom of the fuel assembly skeleton and are consolidated into containers. In the case of removed defective fuel rods, the replacement fuel rods are pulled into the fuel assembly skeleton from the bottom for fuel assembly reconstitution. Pulling fuel rods into the fuel assembly skeleton from the bottom also is a preferred method of original fuel assembly manufacture and avoids the problem of top loading of fuel rods where the advancing rod impinges on a mixing vane grid damaging the vane and/or scratching the rod. In FIG. 4, a nuclear reactor fuel assembly bottom nozzle to guide thimble attachment system is shown for a second embodiment of the apparatus of the invention, in which a top-insertable bolt fastener 52 is used for the attachment. By "top-insertable" is meant insertable from the top of the fuel assembly. The bottom nozzle adaptor plate 22b has a threaded bore 54. The lower end of the guide thimble 14 has an attached (e.g. welded) bottom end plug 28. The bottom end plug 28 has an axial passageway 30 which is aligned with the bottom nozzle adaptor plate's bore 54. The bolt fastener 52, seen in FIGS. 4 and 5, has a longitudinal flow hole 56 to allow passage of coolant. The shank portion 58 has a threaded section 60. The head 62 is sized to block passage through the passageway 30. The bolt fastener 52 is placed in the passageway 30 and threadably inserted in the bore 54. The head 62 is located in the guide thimble 14 proximate the guide thimble bottom end plug 28. By that is meant the head 62 faces in the direction of the top nozzle 20. Typically, the bolt fastener is installed underwater on an upright irradiated fuel assembly at the time of fuel assembly reconstitution. However, it is possible to install the bolt fastener arrangement at the time of fuel assembly original manufacture (in place of the two-headed bolts previously discussed). The head 62 can be any standard bolt head, but a preferred head 62 has a face 64 that includes a polygonal-shaped recess 66. In an exemplary arrangement, the head has a locking cut 68 which is crimped-locked to the inside wall of the guide thimble 14 to prevent loosening. The bolt fastener 52 arrangement allows for top insertion during reconstitution to attach the bottom (or lower) nozzle 12 to the guide thimbles 14. Presently, bolts or screws are bottom inserted for this attachment. The bolt fastener 52 arrangement allows for top threading to attach the bottom (or lower) nozzle 12 to the guide thimbles 14 without having to invert the fuel assembly 10. Presently, the fuel assembly must be inverted for this attachment. Such assembly work on an irradiated fuel assembly must be done under water. The bottom (or lower) nozzle may be attached to an irradiated fuel assembly as one of the steps during a fuel assembly reconstitution procedure after the defective fuel rods have been exchanged for replacement fuel rods. Hence, in this case, the bolt fastener 52 arrangement allows for fuel assembly reconstitution without inverting the fuel assembly. To attach the bottom (or lower) nozzle 12 to the guide thimbles 14 of the fuel assembly 10, the fuel assembly 10 is placed in a generally upright position, or at least with its top nozzle 20 higher than its bottom nozzle 12. A bottom (or lower) nozzle 12 is obtained wherein the bottom nozzle adaptor plate 22b has a plurality of threaded bores 54. Then, a long-handled wrench, detachable holding the bolt fastener 52, is inserted into each guide thimble 14 from the top nozzle 20 towards the bottom (or lower) nozzle 12. It is noted that the wrench can enter the guide thimble as easily as can a control rod and this step can be performed with the top nozzle 20 attached. The wrench is used to thread the bolt fastener 52 and then is detached therefrom. When all the bolt fasteners 52 are thus threaded (and crimp-locked, as desired), the bottom (or lower) nozzle 12 will be secured. The bottom (or lower) nozzle 12 used during the reconstitution may be the previously-removed bottom nozzle of, for example, original manufacture or a replacement bottom nozzle providing the adaptor plate has threaded bores. It is noted that if the adaptor plate 22a of the two-headed bolt 24 of FIG. 2 had a threaded bore, then the area of the shank 34 of the two-headed bolt 24 surrounded by such threaded bore would itself be without threads. Similarly, where the guide thimble bottom end plug of original manufacture has a threaded axial passageway (see FIG. 2), the bolt fastener 52 of the reconstituted fuel assembly would have a shank 58 in which the area of the shank 58 surrounded by such threaded axial passageway would itself be without threads (see FIG. 4). Of course, if the bolt fastener 52 were used for original manufacture, as well as for reconstitution, then the guide thimble bottom end plug's axial passageway would not be threaded. It is noted that with the above-described invention, the attachment system allows for a second, third, or any number of reconstitutions of the fuel assembly. It will be apparent that many modifications and variations are possible in light of the above teachings. It, therefore, is to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.
	description	1. Field of the Invention This invention relates generally to nuclear reactors and, more particularly, to a method and apparatus for clamping a riser brace assembly to a jet pump assembly of a boiling water reactor. 2. Description of Related Art A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends, e.g., by a bottom head and a removable top head. A top guide typically is spaced above a core plate within the RPV. A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure. Particularly, the shroud has a generally cylindrical shape and surrounds both the core plate and the top guide. There is a space or annulus located between the cylindrical reactor pressure vessel and the cylindrically-shaped shroud. FIG. 1 is a schematic, partial cross sectional view, with parts cut away, of a reactor pressure vessel (RPV) 20 for a boiling water reactor. The RPV 20 has a generally cylindrical-shape and is closed at one end by a bottom head and at its other end by removable top head (not shown). A top guide (not shown) is situated above a core plate 22 within RPV 20. A shroud 24 surrounds core plate 22 and is supported by a shroud support structure 26. A downcomer annulus 28 is formed between shroud 24 and sidewall 30 of RPV 20. An annulet nozzle 32 extends through sidewall 30 of RPV 20 and is coupled to a jet pump assembly 34. Jet pump assembly 34 may include a thermal sleeve 36 which extends through nozzle 32, a lower elbow (only partially visible in FIG. 1), and a riser pipe 38. Thermal sleeve 36 is secured at a first end (not shown) to a second end of the lower elbow. The first end of thermal sleeve 36 is welded to the second end of the lower elbow. A first end of the lower elbow similarly secured, or welded, to one end of riser pipe 38. Riser pipe 38 extends between and substantially parallel to shroud 24 and sidewall 30. A riser brace assembly 40 stabilizes a riser pipe 38 within the RPV 20. The riser brace assembly 40 may be fabricated of type 304 stainless steel which, after periods of use, is susceptible to cracking at welded joints. The riser brace assembly 40 is fixedly connected between shroud 24 and sidewall 30, and primarily provides lateral support to the jet pump assembly 34 via riser pipe 38, as shown in FIG. 1. Additionally the riser brace assembly 40 is designed to accommodate for differential thermal expansion that results from reactor start-up and heat-up, and flow induced vibration that is incumbent in the reactor water recirculation system (not shown). FIG. 2 illustrates a riser brace assembly 40 of FIG. 1. The riser brace assembly 40 primarily provides lateral support to the jet pump assembly 34 via riser pipe 38, and includes a riser brace block 43 and two riser brace leaves, an upper riser brace leaf 41 and a lower riser brace leaf 42. Leaves 41 and 42 are attached to the riser brace block 43 by welds, and the riser brace block 43 is welded to a support pad 130 which in turn is attached to a RPV sidewall 30. At the other end, the riser brace assembly 40 is connected to a yoke, such as brace plate 49, which is typically a ½-inch thick plate that is welded to the riser pipe 38. In the riser brace assembly 40 of FIG. 2, there may be numerous weld sites including welds that attach the riser brace plate 49 to riser pipe 38, welds attaching the riser brace block 43 to the support pad 130, and welds attaching the leaves 41 and 42 to the brace plate 49. These welds are typically field welds (made on site). The welds connecting riser brace block 43 to upper and lower riser brace leaves 41 and 42 are shop welds (e.g., pre-fabricated in the shop). FIGS. 3A and 3B illustrate another riser brace assembly 40. This riser brace assembly 40 also provides lateral support to the jet pump assembly via riser pipe 38, and includes a riser brace support 49 and two riser brace leaves, an upper riser brace leaf 41 and a lower riser brace leaf 42. However, in this assembly, the riser brace support 49 is welded to the riser pipe 38 at two weld sites. The two welds attaching the riser brace support 49 to the riser pipe 38 are designated as RS-8 and RS-9, as shown in cross section A-A in FIG. 3B. In addition, the welds attaching the riser brace leaves 41, 42 to the riser brace support 49 are indicated as RB-2a and RB-2c. It should be understood that only two weld points RB-2a, RB-2c are shown in this figure since welds RB-2b and RB-2d (not shown) are hidden in the figure. However, lack of weld integrity will lead to failure of the riser brace assembly which provides support to the jet pump assembly. For instance, weld failure due to vibration fatigue, and/or weld cracking due to intergranular stress corrosion cracking (IGSCC) could cause one of the welds joining the riser brace assembly 40 to the RPV 20 to fail. As an illustrative point, FIG. 3A illustrates a cracked weld RS-9 between the riser brace assembly 40 and the riser pipe 38. Separation of the riser brace assembly 40 near this or any other weld area could adversely impact safety in BWRs. Potentially, should a riser brace assembly 40 break away from RPV 20 (e.g., at RPV sidewall 30) and/or the riser pipe 38, the riser pipe 38 may become unstable, and the jet pump assembly 34 could be adversely affected. If just one jet pump assembly is damaged, a substantial amount of piping must either be replaced or repaired. Since weld repairs in the area of the downcomer annulus 28 are typically not practical due to inaccessibility, and the potential for excessive radiation exposure to personnel is real, a need exists for a method and apparatus of securely clamping the riser braces to the jet pump assembly. Accordingly, the present invention provides a method and apparatus for mechanically clamping the riser brace assembly to the jet pump riser pipe, more particular, structurally replacing welds that attach a riser brace assembly to a jet pump riser pipe. In an exemplary embodiment, the riser brace clamp assembly may include an upper clamp assembly, a lower clamp assembly, and a plurality of mechanical fasteners to provide clamping forces to the upper clamp assembly and the lower clamp assembly. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the upper clamp assembly having an upper clamp and an upper frame. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the lower clamp assembly having a lower clamp and a lower frame. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the upper clamp assembly and the lower clamp assembly which sandwich a riser brace support, the riser brace support provided with at least one through-hole to accommodate the plurality of mechanical fasteners. In yet other exemplary embodiments, the mechanical fasteners are clamping bolts and clamping bolt nuts. In yet other exemplary embodiments, the clamping bolt nuts engage a bolt nut latch spring to permit the rotation of the bolt nuts in only one direction. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the upper clamp having adjustable wedges that adjust to interface the jet pump riser pipe, a jack bolt for adjusting the wedges to a desired position, and a jack bolt latch spring for permitting rotation of the jack bolt in only one direction. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the lower clamp having adjustable wedges that adjust to interface the jet pump riser pipe, a jack bolt for adjusting the wedge to a desired position and a jack bolt latch spring for permitting rotation of the jack bolt in only one direction. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the upper frame having shear pads for preventing deformation and bending when a clamping force is applied. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the lower frame having shear pads for preventing deformation and bending when a clamping force is applied. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the upper frame accommodating latch spring which engages with a latch teeth of a clamp bolt nut to prevent rotation of a bolt nut. Other exemplary embodiments of the apparatuses and methods of the invention separately provide the lower frame having a square counter bore recess which engages with a clamp bolt to prevent rotation of the bolt. These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the apparatuses and methods according to the invention. A riser brace assembly in accordance with the invention is designed to structurally replace weld(s) attached between a riser brace support and a riser pipe. In general, the installation involves electric discharge machining (EDM) the riser brace support to install the riser brace clamp assembly, assembling the hardware in the reactor, adjusting wedges to secure proper interface of the clamp assembly to the riser pipe, and preloading and locking a plurality of mechanical fasteners to secure the riser brace assembly in place. In order for the riser brace clamp assembly to interface with the riser pipe, adjustable wedges are radially moved so that the upper and lower clamps clamp tightly on the riser pipe. These wedges may be advanced by rotation of mechanical fasteners, for example, but not limited to jack bolts. Additionally, latches are provided to lock the mechanical fasteners, and thus secure the fasteners and wedges in the desired position. FIG. 4 is an isometric view of a riser brace clamp assembly 50 in accordance with an exemplary embodiment of the invention. The riser brace clamp assembly 50 provides lateral support to the riser pipe 38 and the jet pump assembly. The riser brace clamp assembly 50 includes an upper clamp assembly 51, a lower clamp assembly 52, and a plurality of mechanical fasteners 71, 72, 73. The upper clamp assembly 51 and the lower clamp assembly 52 sandwich a riser brace support 49 (shown in FIG. 6). Upper clamp assembly 51 and lower clamp assembly 52 are securely fixed to a riser brace support 49 by a plurality of mechanical fasteners, for example, clamp bolts 71, frame bolts 72, and bolt nuts 73. It should be appreciated that other fasteners may be utilized besides the nut and bolt arrangement. The upper clamp assembly 51 includes an upper clamp 53 and an upper frame 54 that engage with each other. The upper frame 54 includes two large pockets 77 (shown in FIG. 5) on the top surface of the upper frame 54 so that an end of the upper clamp 53 may be fittingly received for securement. The pockets 77 may include a slotted hole via the upper frame 54 to accommodate the clamp bolts 71. Further, the upper frame 54 includes a curved surface 58 on the inner side of the frame so as to receive the outer surface of the riser pipe 38 (not shown). The curved surface 58 may be machined beforehand to have a radius to respectively fit the radius of the riser pipe 38. The upper frame 54 may include additional slots, holes, and under-cuts to contain other parts. As an exemplary embodiment, the upper frame 54 includes slots 62 to accommodate a frame latch spring 65 and a bore hole 80 to receive bolt nut 73. The slots 62 may be positioned near the ends of the upper frame 54 and adjacent to the bore hole 80. The slots 62 should be adjacent to the bore hole 80 so that latch spring 65 engage the bolt nut 73 in the upper frame 54. The engagement of the latch spring 65 to the bolt nut 73 will be discussed in detailed later. The upper clamp 53 includes slots and holes to accommodate and receive various parts. As an exemplary embodiment, slots 61, 63 may be provided to accommodate latch springs 85, 95, respectively, a bore hole 81 may be provided to receive a bolt nut 73, a hole 74 may be provided to receive a bolt 76 (i.e., a jack bolt), and a wedge slot 79 may be provided to receive wedge 98. In the exemplary embodiment, the upper clamp 53 may include two slots 61, two slots 63, two bore holes 81, two bolt holes 74 and two wedge slots 79. However, it should be appreciated that the upper clamp 53 may include more than two slots 63, 79 and holes 74 to accommodate the adjustable wedges 98. Slot 61 should be adjacent to the bore hole 81 so that latch spring 85 engage the clamp bolt nut 73. The bore hole 81 accommodates the clamp bolt 71. Slot 63 should be adjacent to the bolt hole 74 so that latch spring 95 may engage the jack bolt 76. Because vibration is a major concern in a reactor water recirculation system due to reactor recirculation pumps, various parts may become loose. For example, jack bolts 76 may become loosen if enough vibration is generated. Thus, latch springs 95 are provided to engage a teeth 78 in the head of the jack bolt 76 with a teeth 97 of the latch spring 95 to prevent rotation of the jack bolt 76. Hole 74 accommodates the jack bolt 76, which in turn moves the wedge 98 to interface with the riser pipe 38. The jack bolt 76 includes equally spaced ratchet teeth 78 which are machined into the periphery of the jack bolt head. These ratchet teeth 78 engage the teeth 97 (shown in FIG. 5) of the latch spring 95. This locks the jack bolt 76 in position and prevents the jack bolt 76 from becoming loose in a flow-induced vibration environment which is indigenous to a riser brace assembly 50. The jack bolt 76 may rotate so as to adjust the position of the wedge 98. The rotation of the jack bolt 76 may be performed with a hexagonal wrench which accommodates the jack bolt 76 via an internal hexagon interior shape in the head of the jack bolt 76. As the jack bolt 76 is rotated, the wedge 98 moves in the wedge slots 79, and thus reduces the radial distance (gap) between the wedge 98 and the riser pipe 38. The lower frame 56 is essentially identical to the upper frame 54, except a bottom surface of lower frame 56 includes a counter-bore recess (not shown). It should be appreciated that the counter-bore recess can be in a shape of a square so as to receive the square head of the frame bolt 72. The counter-bore recess ensures that the frame bolts 72 do not rotate under the action of applying torque to the bolt nuts 73. As an exemplary embodiment, the head of the frame bolt 72 may be a hexagonal shaped head. Further, the lower frame 56 will not include slots 62 found in the upper frame 54 since the bolt nuts 73 only engage with the upper frame 54. In the exemplary embodiment, the upper clamp 53 and lower clamp 55 may be formed in a U-like shape. However, it should be understood that the upper and lower clamps 53, 55 can be in other shapes, which is dependent on the design of the riser pipe 38. The lower clamp 55 is essentially identical to the upper clamp 53, except a bottom surface of lower clamp 55 includes a counter-bore recess (not shown). It should be appreciated that the counter-bore recess can have a square feature to interface with a square male feature in the head of the clamp bolt 71. The counter-bore recess ensures that the clamp bolts 71 do not rotate under the action of applying torque to the bolt nuts 73. It should be understood that the shape of the counter-bore recess should match the shape of a projection 91a (shown in FIG. 5) in the head of the clamp bolt 71. The head of the clamp bolt 71 may be a hexagonal shaped head. FIG. 5 is a exploded prospective view of the riser brace assembly shown in FIG. 4, in accordance with an exemplary embodiment of the invention. As mentioned, the riser brace clamp assembly 50 includes an upper clamp assembly 51, lower clamp assembly 52, and a plurality of mechanical fasteners (e.g., clamp bolts 71, frame bolts 72, and bolt nuts 73). The clamp and frame bolts 71, 72 may preferably contain external 13/16-16UN threads at the distal end and a flange 91 at a proximal end (bolt head end). The flange 91 provided at the proximal end seats in a counter-bore recess (not shown) of the lower clamp 55 and lower frame 56 upon assembly. The flange 91 may include a square-like shaped protrusion 91a extending slightly outward from the shank of the bolts 71, 72 so that the protrusion 91a tightly seat with a square counter-bore recess. This ensures that the bolts 71, 72 will not rotate when torque is applied to the bolt nuts 73, and prevents rotation under all conditions (i.e., flow induced or vibration). The bolt nuts 73 may accommodate both the clamp bolt 71 and frame bolt 72 since the bolts 71, 72 are nearly identical. The bolt nuts 73 may preferably be threaded with an internal 13/16-16UN tap (not shown), although other tap dimensions are within the purview of this invention. Further, the bolt nut 73 may include equally spaced ratchet teeth 75 that are machined into the outer circumference of the head of bolt nuts 73. The ratchet teeth 75 engages with spring latches 65 and 85 in the upper frame 54 and upper clamp 53, respectively. Frame bolt nut spring latch 65 and clamp bolt nut spring latch 85 each include ratchet teeth 67 and 87, respectively, that interface with bolt nut ratchet teeth 75. As the bolt nuts 73 are rotated in the direction to increase bolt preload, the springs and latches behave like cantilever beams in deflecting the necessary distance to allow rotation of the respective nuts 73. The ratchet teeth 75 in the bolt nut 73 and ratchet teeth 67, 87 in the latch springs 65, 85 are oriented such that rotation in the desired direction is permitted. The bolt nuts 73 can be removed only after the latch springs 65, 85 and ratchet teeth 75 in the bolt nut 73 and teeth 67, 87 in the springs 65, 85 have been “cammed back” to provide clearance for the subject teeth. Spring latch 95 resides in a machined slot 63 and similarly functions the same as latch 65, 85 except the latch 95 interface with a bolt 76. For example, but not limited to, the bolt 76 may be a jack bolt. The jack bolt 76 includes equally spaced ratchet teeth 78 which are machined into the periphery of the jack bolt head. The ratchet teeth 78 engage teeth 97 of the spring latch 95 to lock the jack bolt 76 in position and prevent the jack bolt 76 from becoming loose when vibration is produced in the jet pump assembly. The rotation of the jack bolt 76 adjusts the position of the wedge 98. The wedge 98 is provided in a wedge slot 79. The purpose of the wedge slot 79 is to maintain the moveable wedge 98 in place until the jack bolt 76 rotates to cause a change in position. The wedge 98 includes a projection 99 that slides into an opening 88 in the wedge slot 79. The opening 88 accommodates the jack bolt 76 to extend through so that the jack bolt 76 may thread into the projection 99 in the wedge 98. As the jack bolt 76 rotates by tightening the bolt 76, the wedge 98 moves in the radial direction towards the center of the riser pipe 38. This produces an interface on the pipe 38 as the wedge 98 moves radially towards the center, and thus provides the riser brace assembly 50 to have a tight secure interface with the riser jet pipe 38. The tight interface produced by the wedge 98 is caused by the shape of the wedge 98 (e.g., “wedge-like” shape). In other words, the wedge 98 having a longer base near the bottom and becoming narrower towards the top. Accordingly, as the jack bolt 76 is tightened, the wedge 98 is drawn up by virtue of the threaded engagement. As the wedge 98 is drawn up, it moves radially towards the surface of the riser pipe 38. Although the wedge 98 acted upon by the jack bolt 76 may result in a radial force imparted to the riser pipe 38, it should be appreciated that the clamping forces are generated by the wedge features of the upper and lower clamps 53, 55 interfacing with the wedge pockets 77 acted upon by the clamp bolts 71. The jack bolts 76 are not large enough to provide the needed preload (e.g., the required clamping force). It should be appreciated that wedge 98 may encompass other shapes besides the one shown in the exemplary embodiment. It should further be appreciated that the slot 63 will be dependent on the outer shape of the wedge 98. This ensures a proper fit and securement. Shear pads 90 may be included in the upper and lower frames 54, 56. The upper and lower frames 54, 56 are machined with shear pads 90 at the back surface of the frames so as to come into contact with the vertical surface of the riser brace support 49 (shown in FIG. 6). These shear pads 90 prevent deformation or bending of the frame components when subjected to clamping forces induced by the assembly. FIG. 6 illustrates the connection of the riser brace clamp assembly 50 within a riser pipe 38 in accordance with an exemplary embodiment of the invention. Specifically, FIG. 6 illustrates a isometric view of riser brace clamp assembly 50 in order to more clearly depict how the various components of the riser brace clamp assembly 50 interface with the riser pipe 38. The riser brace clamp assembly 50 provides lateral support to the riser pipe 38 and the jet pump assembly. The riser brace clamp assembly 50 includes an upper clamp assembly 51, a lower clamp assembly 52, a riser brace support 49, and two riser brace leaves (e.g., an upper riser brace leaf 41 and a lower riser brace leaf 42). At one end, the leaves 41 and 42 can be welded to a support pad which in turn is affixed to RPV sidewall (not shown). At the other end, leaves 41 and 42 of the riser brace clamp assembly 50 are connected, preferably by welds to a riser brace support 49. It should be appreciated that chamfers may be incorporated into the design of the frame components 54, 56 to provide clearance and afford visual inspection of the welds that join the riser brace leaves 41, 42 to the riser brace support 49. FIG. 7 is a flowchart illustrating an exemplary method of clamping a riser brace assembly to the jet pump riser pipe in accordance with the invention. In general, after reactor safety procedures for maintenance/repair personnel have been complied with, and an overall inspection of the installation locations has been videotaped, looking for anything unexpected relating to the as-built configuration of the riser brace assemblies, which is transported by special tooling connected to clamp apparatus at several locations to a submerged location in the reactor, is installed. Prior to the installation, if there are any obstructions on the riser brace support, specifically on the upper and lower horizontal surfaces where the frame 54 and 56 interface with the support, the obstruction may be removed by electric discharge machining (EDM) and/or grinding with an abrasive material, as is known. Specifically, holes are machined in the riser brace support 49 (Step S100). This may be accomplished by in-vessel machining (e.g., electric discharge machining (EDM). The through-holes produced in the riser brace support 49 accommodate mechanical fasteners 71, 72. It is preferable that the riser brace support 49 may have four holes to accommodate each of the mechanical fasteners 71, 72. As maneuvering within RPV is difficult, since the riser brace clamp assembly 50 is to be installed remotely that is often in excess of 60 feet away from the free surface of the water which floods the reactor cavity. A reactor cavity is flooded with water to protect personnel from radiation hazard. Accordingly, it may be necessary to pre-assembly the components as much as possible. In general, the jack bolts 76, adjustable wedges 98 and jack bolt latches 95 in the upper clamp 53 and lower clamp 55 may be pre-assembled prior to installation. Other pre-assembly may include the latch springs 65 in the upper frame 54 and latch springs 85 in the upper clamp 53. Next, the components of riser brace clamp assembly 50 are assembled in the reactor on the riser brace assembly (step S200). Particularly, the upper frame 54 and the lower frame 56 are positioned in the RPV with the frame bolts 72 extending through holes 80. Once the bolts 72 are received by the holes 80 in the upper frame 54, nut bolts 73 are installed to engage the frame bolts 72 for securement. Thereafter, the components of the upper clamp 53 and the lower clamp 55 are installed. The upper clamp 53 engagingly slides into the wedge pockets 77 found in the upper surface of the upper frame 54. The lower clamp 55 engagingly slides into the wedge pockets 77 found in the bottom surface of the lower frame 56. As the frame components 54, 56 and the clamp components 53, 55 are engaged, clamp bolts 71 extend through holes 81. Once the clamp bolts 71 are received by the holes 81 in the upper clamp 53, nut bolts 73 are installed to secure the clamp bolts 71 to the assembly 50. Nominal clamping forces are applied (step S300) to fixedly secure the riser brace clamp assembly 50 to the riser pipe 38. The clamping forces may also properly align and configure the components of the clamp assembly 50 on the riser brace assembly 40. The bolt nuts 73 on the frame bolts 72 are installed and initially tightened to a desired torque (e.g., to 2+/−1 lb-ft, for example). Then the bolt nuts 73 are gradually torqued (in 5 lbs-ft increments up to 30 lbs-ft, for example) in simultaneously or in alternating fashion to maintain even pressure on the clamp assembly 50 (step S400). This ensures that the force is evenly distributed to both the upper and lower frames 54, 56, respectively. It should be appreciated that the teeth 67 in the latch springs 65 are fully engaged with the teeth 75 of the nut bolts 73 at this juncture. This ensures that the nut bolts 73 will rotate is in only one direction. After the upper clamp 53 and lower clamp 55 are configurable aligned and properly on the riser brace assembly 40 and with clamp bolt nuts 73 fully engaged with the latch springs 85, the wedges 98 provided in slots 79 are adjusted to apply the proper interface on the riser pipe 38 (step S500). Adjustments may be needed to obtain uniform contact of the clamps to the riser pipe 38. The jack bolt 76 can be designed with an internal hexagonal head and rotated with a hexagonal-fitted wrench. As the jack bolt 76 rotates, the wedges 98 move in the wedge pockets 79 which move with a radial component of direction towards the center of the riser pipe 38. Because the jack bolt 76 is threaded into the adjustable wedges 98, the action of rotating the jack bolt 76 pulls or draws the wedges 98 up the wedge slots 79. Since the wedge slots 76 are oriented at an angle in the vertical position, as the wedges 98 are drawn up, the wedges 98 move radially closer to the center of the riser pipe 38. It should be appreciated that the wedges 98 are independent from each other so as to provide adjustments to interface the surface of the riser pipe 38 that may not be perfectly round. This radial component of direction provides the wedges 98 to have a tight secure interface to the riser jet pipe 38. Once the wedges 98 have been adjusted to a tight fit, a final clamping torque is applied on the clamp bolts 71 to provide a final pre-load on the bolts (step S600). The clamp bolts 71 may be gradually pre-loaded simultaneously or in alternating fashion to maintain even pressure on the clamp assembly 50. This ensures that the force is evenly distributed to both the upper and lower clamp assemblies 51, 52. The installed riser brace clamp assembly 50 structurally replaces welds that attach a riser brace assembly to a jet pump riser pipe. Additionally, the installed riser brace clamp assembly 50 may stiffen the entire jet pump assembly, thereby decreasing the natural vibration frequency. This is significant due to the flow-induced vibration that is inherent in a jet pump assembly of a BWR. The riser brace clamp assembly 50 may also be designed to accommodate the differential thermal expansion that results from reactor start-up and heat-up, and to accommodate the flow-induced vibration that is incumbent in the reactor water recirculation system (not shown) due to reactor recirculation pumps. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
	description	1. Field of the Invention This invention relates to a radiation image read-out method, a radiation image read-out apparatus and a stimulable phosphor sheet, and more particularly to a radiation image read-out method and a radiation image read-out apparatus for reading out a radiation image stored on a stimulable phosphor sheet by the use of a line sensor, and a stimulable phosphor sheet suitable for the method and the apparatus. 2. Description of the Related Art When certain kinds of phosphor are exposed to a radiation such as X-rays, they store a part of energy of the radiation. Then when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light, light is emitted from the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is generally referred to as “a stimulable phosphor”. In this specification, the light emitted from the stimulable phosphor upon stimulation thereof will be referred to as “stimulated emission”. There has been known a radiation image recording and reproducing system in which a stimulating light beam such as a laser beam is projected onto a stimulable phosphor sheet (a sheet provided with a layer of the stimulable phosphor) which has been exposed to a radiation passing through an object such as a human body to have a radiation image of the object stored on the stimulable phosphor sheet, and the stimulated emission emitted from the stimulable phosphor sheet is photoelectrically detected, thereby obtaining an image signal (a radiation image signal). A radiation image of the object is reproduced as a visible image on the basis of the radiation image signal on a recording medium such as a photographic film or a display such as a CRT. See, for instance, Japanese Unexamined Patent Publications Nos. 55(1980)-12429, 56(1981)-11395 and 56(1981)-11397. The stimulable phosphor sheet generally comprises a protective layer which protects the surface of the stimulable phosphor layer on the side from which the stimulated emission is detected and a support which supports the stimulable phosphor layer from the side opposite to the protective layer, and is flexible. As a system for reading out radiation image information from the stimulable phosphor sheet, there have been known a point scan system in which the stimulating light is focused in a spot on the surface of the stimulable phosphor sheet, the spot is caused to scan the surface of the stimulable phosphor sheet by the use of a scanning optical system comprising, for instance, a laser and a polygonal mirror while moving the stimulable phosphor sheet in a direction intersecting the direction of scan of the stimulating light spot, and stimulated emission emitted from the points of the stimulable phosphor sheet is led to a photomultiplier by a light guide such as of acrylic resin, and a line scan system in which a linear stimulating light beam is projected onto the stimulable phosphor sheet to irradiate a line-like portion extending in one direction while moving the stimulable phosphor sheet in a direction intersecting said one direction and stimulated emission emitted from the line-like portions is imaged on a line sensor having an array of photoelectric convertor elements. As a means for imaging the stimulated emission in the line scan system, for instance, an imaging lens comprising an array of a plurality of refractive index profile type lenses may be employed. The imaging lens images the line-like portion of the stimulable phosphor sheet as an erected image of natural size, whereby the line sensor detects the amount of stimulated emission emitted from the line-like portion. In this case, it is necessary to keep the distance between the surface of the stimulable phosphor layer and the imaging lens in a range where a relation necessary for the imaging lens to image the surface of the stimulable phosphor layer on the line sensor (this relation will be referred to as “imaging relation”, hereinbelow) can be held. That is, when the distance between the surface of the stimulable phosphor layer and the imaging lens changes, the imaging lens can come to be disabled from imaging a particular part of the surface of the stimulable phosphor layer on a predetermined photoelectric convertor element of the line sensor, which can result in reduction of the amount of stimulated emission detected by the predetermined photoelectric convertor element due to poor light collecting efficiency and/or generation of noise in the radiation image information obtained due to stimulated emission impinging upon a wrong photoelectric convertor element. This problem may be overcome by supporting the supported surface of the stimulable phosphor layer (the surface opposite to the surface of the stimulable phosphor layer on the side from which the stimulated emission is detected (will be referred to as “the detected surface”, hereinbelow)) by a rigid support so that the detected surface of the stimulable phosphor layer conforms to the shape of the surface of the support, whereby the distance between the detected surface of the stimulable phosphor layer and the imaging lens is kept constant. However, even if the supported surface of the stimulable phosphor layer is supported by a rigid support, the detected surface cannot always conform to the shape of the surface of the support, and at the same time, the detected surface of the stimulable phosphor layer actually has unevenness and/or undulation and accordingly, it is difficult to move the stimulable phosphor sheet keeping constant the distance between the detected surface of the stimulable phosphor layer and the imaging lens. In view of the foregoing observations and description, the primary object of the present invention is to provide a radiation image read-out method and a radiation image read-out apparatus which can read out the image recorded on the stimulable phosphor sheet more accurately than conventional methods and conventional apparatuses, and to provide a stimulable phosphor sheet suitable for the method and the apparatus. In accordance with a first aspect of the present invention, there is provided a radiation image read-out method in which a stimulable phosphor sheet comprising a stimulable phosphor layer in contact with a protective layer which is rigid and transparent is used, stimulating light is projected onto the stimulable phosphor sheet from the protective layer side, stimulated emission emitted from the stimulable phosphor layer upon exposure to the stimulating light is detected by imaging the stimulated emission on a line sensor by an imaging lens from the protective layer side while moving the stimulable phosphor sheet relatively to the line sensor in a direction intersecting the direction in which the line sensor extends. In accordance with a second aspect of the present invention, there is provided a radiation image read-out apparatus comprising a stimulable phosphor sheet having a stimulable phosphor layer in contact with a protective layer which is rigid and transparent, a stimulating light projecting means which projects stimulating light onto the stimulable phosphor sheet from the protective layer side, a detecting means which detects stimulated emission emitted from the stimulable phosphor layer upon exposure to the stimulating light by imaging the stimulated emission on a line sensor by an imaging lens from the protective layer side, and a conveyor means which moves the stimulable phosphor sheet relatively to the detecting means in a direction intersecting the direction in which the line sensor extends. It is preferred that the stimulable phosphor sheet be conveyed relatively to the detecting means by the conveyor means so that the surface profile of the surface of the stimulable phosphor layer facing the protective layer is positioned within the range of the focal depth of the imaging lens. In accordance with a third aspect of the present invention, there is provided a stimulable phosphor sheet comprising a stimulable phosphor layer and a protective layer, stimulating light being projected onto the stimulable phosphor layer from the protective layer side and stimulated emission emitted from the stimulable phosphor layer upon exposure to the stimulating light being detected by a line sensor through an imaging lens from the protective layer side, wherein the improvement comprises that the protective layer is formed of a rigid transparent material and the stimulable phosphor layer is in contact with the protective layer. It is preferred that the stimulable phosphor layer be in contact with the protective layer at a plurality of discontinuous contact areas. It is preferred that the surface of the stimulable phosphor layer facing the protective layer be within the range of ±100 μm in surface profile error. It is preferred that the surface of the stimulable phosphor layer facing the protective layer be in the range of not smaller than 0.05 μm and not larger than 5 μm in center line surface roughness. It is preferred that the protective layer be in the range of not smaller than 0.2 mm and not larger than 10 mm in thickness. The stimulable phosphor layer may be pressed toward the protective layer from the side opposite to the protective layer by an elastic member so that the surface of the stimulable phosphor layer facing the protective layer is brought into contact with the protective layer. The surface of the stimulable phosphor layer facing the protective layer may be bonded to the surface of the protective layer facing the stimulable phosphor layer by contact bonding under heat. The surface of the stimulable phosphor layer facing the protective layer may be in direct contact with the protective layer by way of contact areas or may be in indirect contact with the protective layer by an intervenient such as adhesive. In the latter case, it is necessary that the surface of the stimulable phosphor layer is caused to conform to the surface of the protective layer by way of the intervenient. The term “surface profile” as used here means a profile of the surface including shape, undulation, roughness and the like. The expression “the focal depth of the imaging lens” as used here means an acceptable range of error in setting the distance between a light emitting surface emitting a given amount of light and the imaging lens with the reduction of light received by a light receiving surface held within 15% of that when the light emitting surface is precisely imaged on the light receiving surface by the imaging lens. The term “surface profile error” as used here means an error from an optimal profile based on designing (that is, the total of an error in shape, an error in surface undulation, an error in surface roughness and the like). The “optimal profile” means a profile precisely imaged on the line sensor by the imaging lens. The surface profile error is represented by a plus error and a minus error from the optimal profile. The stimulable phosphor layer may be in contact with the protective layer by way of filler with a void formed between the stimulable phosphor layer and the protective layer. The filler may be positioned on a coating layer formed on the stimulable phosphor layer and/or the protective layer. In this case, it is preferred that the thickness of the coating layer be in the range of not smaller than 0.1 μm and not larger than 20 μm, and the particle diameter of the filler be in the range of not smaller than 0.2 μm and not larger than 50 μm. As the filler, short fiber or beads of glass, polymer or the like can be employed. The coating layer may be formed by applying a coating solution to the stimulable phosphor layer and/or the protective layer. That the filler is positioned on a coating layer means that the filler is positioned on the coating layer to project at least partially from the surface of the coating layer so that a void is formed between the stimulable phosphor layer and the protective layer. The filler may be partially embedded in the coating layer. In the radiation image read-out method and apparatus of the present invention, the protective layer side surface of the stimulable phosphor layer conforms to the surface of the protective layer which is rigid and accordingly has a highly precise surface profile following the surface profile of the protective layer. As a result, the distance between the surface of the stimulable phosphor layer facing the protective layer can be set more close to a predetermined optimal distance than in the conventional method and apparatus, whereby the whole region of the surface of the stimulable phosphor layer on which a radiation image is recorded can be more uniformly imaged on the line sensor and the radiation image recorded on the stimulable phosphor sheet can be more uniformly and more precisely read out. The “optimal distance” is a distance at which the surface of the stimulable phosphor layer facing the protective layer can be precisely imaged on the line sensor by the imaging lens when the stimulated emission is to be detected. The protective layer is generally bonded to the stimulable phosphor layer by adhesive or the like. Since the adhesive layer and the protective layer are higher than air in refractive index, there is a fear that the exit angle at which the stimulated emission emitted from the stimulable phosphor layer emanates from the stimulable phosphor sheet into the air can be greatly enlarged by the adhesive layer and the protective layer, which can reduce the amount of the stimulated emission impinging upon the imaging lens. However the contact areas at which the stimulable phosphor layer is actually in contact with the protective layer are very small as compared with the whole area of the stimulable phosphor layer and the protective layer and an air layer is formed over the major part of the stimulable phosphor layer and the protective layer, whereby enlargement of the exit angle at which the stimulated emission emitted from the stimulable phosphor layer emanates from the stimulable phosphor sheet into the air can be suppressed. As a result, the amount of the stimulated emission imaged on the line sensor through the imaging lens can be increased and the radiation image information recorded on the stimulable phosphor sheet can be read at a higher S/N. When one of the stimulable phosphor sheet and the detecting means is conveyed by the conveyor means relatively to the other so that the surface profile of the surface of the stimulable phosphor layer facing the protective layer is positioned within the range of the focal depth of the imaging lens, the whole region of the surface of the stimulable phosphor layer on which a radiation image is recorded can be more uniformly imaged on the line sensor and the radiation image recorded on the stimulable phosphor sheet can be more uniformly and more precisely read out. In the stimulable phosphor sheet of the present invention, the protective layer side surface of the stimulable phosphor layer conforms to the surface of the protective layer which is rigid and accordingly has a highly precise surface profile following the surface profile of the protective layer. As a result, the distance between the surface of the stimulable phosphor layer facing the protective layer can be set more close to a predetermined optimal distance than in the conventional method and apparatus, whereby the whole region of the surface of the stimulable phosphor layer on which a radiation image is recorded can be more uniformly imaged on the line sensor. Further since an air layer is formed over the major part of the stimulable phosphor layer and the protective layer, enlargement of the exit angle at which the stimulated emission emitted from the stimulable phosphor layer emanates from the stimulable phosphor sheet into the air can be suppressed, whereby, the amount of the stimulated emission imaged on the line sensor through the imaging lens can be increased. Further, when the stimulable phosphor layer is in contact with the protective layer at a plurality of discontinuous contact areas, the distance between the surface of the stimulable phosphor layer facing the protective layer and the imaging lens can be set more uniformly and precisely. Further, when the surface of the stimulable phosphor layer facing the protective layer is within the range of ±100 μm in surface profile error, the distance between the surface of the stimulable phosphor layer facing the protective layer and the imaging lens can be set more uniformly and precisely. Further, when the surface of the stimulable phosphor layer facing the protective layer be in the range of not smaller than 0.05 μm and not larger than 5 μm in center line surface roughness, the distance between the surface of the stimulable phosphor layer facing the protective layer and the imaging lens can be set more precisely. Further, since a thin air layer is formed between the protective layer and the stimulable phosphor layer, stimulated emission which is emitted from the stimulable phosphor layer and emanates through the protective layer after reflected in the air layer is concentrated in a narrower region and the amount of stimulated emission imaged on the line sensor by the imaging lens can be increased. Further, when the protective layer is in the range of not smaller than 0.2 mm and not larger than 10 mm in thickness, the protective layer can be rigid enough and becomes less apt to be deformed, whereby the distance between the surface of the stimulable phosphor layer facing the protective layer can be set more uniformly and more close to a predetermined optimal distance. Further, when the stimulable phosphor layer is pressed toward the protective layer from the side opposite to the protective layer by an elastic member so that the surface of the stimulable phosphor layer facing the protective layer is brought into contact with the protective layer, the stimulable phosphor layer can be pressed against the protective layer under a uniform pressure over the entire area of the stimulable phosphor layer, whereby the distance between the surface of the stimulable phosphor layer facing the protective layer can be set more uniformly and more close to a predetermined optimal distance. Further, when the surface of the stimulable phosphor layer facing the protective layer is bonded to the surface of the protective layer facing the stimulable phosphor layer by contact bonding under heat, the surface of the stimulable phosphor layer facing the protective layer is more surely kept following the surface of the protective layer facing the stimulable phosphor layer, whereby the distance between the surface of the stimulable phosphor layer facing the protective layer can be set more uniformly and more close to a predetermined optimal distance. Further, when the stimulable phosphor layer is in contact with the protective layer by way of filler with a void formed between the stimulable phosphor layer and the protective layer, the aforesaid air layer can be more surely formed. When the filler is positioned on a coating layer formed on the stimulable phosphor layer and/or the protective layer, the thickness of the coating layer is in the range of not smaller than 0.1 μm and not larger than 20 μm, and the particle diameter of the filler is in the range of not smaller than 0.2 μm and not larger than 50 μm, the filler particles can be well fixed, whereby stimulated emission emitted from the stimulable phosphor layer can be propagated with a high repeatability, and at the same time, the aforesaid air layer can be created in a thickness optimal to propagation of the stimulated emission. Even if a coating layer is provided on the stimulable phosphor layer and/or the protective layer, the stimulated emission is reflected in random directions when emanating from the coating layer and emanates from the coating layer as light having a substantially Gaussian distribution. Accordingly, advantages of the aforesaid air layer can be obtained without taking into account refraction of the stimulated emission at the interfaces between the stimulable phosphor layer and the coating layer and between the coating layer and the protective layer. As shown in FIGS. 1 and 2, a radiation image read-out apparatus 100 in accordance with a first embodiment of the present invention comprises a stimulable phosphor sheet 1 having a stimulable phosphor layer 3 in contact with a protective layer 2 which is rigid and transparent. The radiation image read-out apparatus 100 further comprises a projecting means 20 which projects a stimulating light beam onto the stimulable phosphor sheet 1 from the protective layer side S (in the direction of arrow S in FIG. 2), a detecting means 30 which images stimulated emission emitted from the stimulable phosphor layer 3 upon exposure to the stimulating light beam on a line sensor 32 through an imaging lens 31 so that the line sensor 32 detects the stimulated emission, and a conveyor means (not shown) which moves one of the stimulable phosphor sheet 1 and the detecting means 30 relatively to the other in a direction intersecting the direction in which the line sensor 32 extends. The stimulable phosphor sheet 1 comprises a stimulable phosphor layer 3 and a protective layer 2. The protective layer 2 is rigid and transparent, and the stimulable phosphor layer 3 is in contact with the protective layer 2. The protective layer 2 may be of any material provided that it is rigid and transparent. For example, the protective layer 2 may be a transparent resin plate such as an acrylic plate. In this particular embodiment, a plane-parallel glass plate is employed as the protective layer 2. The surface profile error of the surface of the protective layer 2 facing the stimulable phosphor layer 3 (the stimulable phosphor layer side P surface) is made not larger than ±100 μm, and the center line mean surface roughness of the surface of the stimulable phosphor layer 3 facing the protective layer 2 (the protective layer side S surface) is made in the range of not smaller than 0.05 μm and not larger than 5 μm. Further, the thickness of the protective layer 2 is made in the range of not smaller than 0.2 mm and not larger than 10 mm and the protective layer side S surface of the stimulable phosphor layer 3 is bonded to the stimulable phosphor layer side P surface of the protective layer 3 by contact bonding under heat. The surface of the stimulable phosphor layer 3 and the surface of the protective layer 2 may be brought into contact with each other in any way without limited to contact bonding under heat. The surface profile error of the aforesaid surface of the protective layer 2, the center line surface roughness of the aforesaid surface of the stimulable phosphor layer 3 and the thickness of the protective layer 2 need not be limited to in the ranges described above. The projecting means 20 comprises a broad area laser 21 which emits a line stimulating light beam and an optical system 22 comprising a toric lens which condenses the line stimulating light beam emitted from the broad area laser 21 in a line-like area of the surface of the stimulable phosphor sheet 1 extending in the direction of arrow X by way of a reflecting mirror 23. The detecting means 30 is further provided with a stimulating light cut filter 33 in addition to the imaging lens 31 and the line sensor 32, and the imaging lens 31 comprises a plurality of lens elements arranged in the direction of arrow X and images a line-like area irradiated by the line stimulating light beam of the surface of the stimulable phosphor layer 3 facing the protective layer 2. The line sensor 32 comprises a plurality of photoelectric convertor elements arranged in the direction of arrow X and detects the amount of stimulated emission emitted from the line-like area imaged by the imaging lens 31. The stimulating light cut filter 33 is inserted between the imaging lens 31 and the line sensor 32 and cuts stimulating light in the stimulated emission. The projecting means 20 and the detecting means 30 are integrated with each other and are moved integrally with each other by the conveyor means (not shown). Though not shown, the conveyor means comprises a guide rail which linearly guides the integrated projecting means 20 and the detecting means 30 in the direction of arrow Y perpendicular to the direction of arrow X not to tilt, and a drive means which moves the integrated projecting means 20 and the detecting means 30 along the guide rail. The operation of the radiation image read-out apparatus 100 of this embodiment will be described, hereinbelow. The stimulating light beam emitted from the broad area laser 21 travels through the condenser optical system 22 and is reflected by the reflecting mirror 23 to irradiate a line-like area of the surface of the stimulable phosphor layer 3 facing the protective layer 2. Stimulated emission emitted from the surface of the stimulable phosphor layer 3 upon exposure to the stimulating light beam is imaged on the line sensor 32 through the imaging lens 31 and is photoelectrically converted into an electric image signal. By executing these steps while conveying the integrated projecting means 20 and detecting means 30 in the direction of arrow Y, radiation image information recorded on the stimulable phosphor sheet 1 is read out. The protective layer 2 is a rigid plane-parallel glass plate and the surfaces of the protective layer 2 are highly flat. The surface of the stimulable phosphor layer 3 facing the protective layer 2 is in contact with the surface of the protective layer 2 facing the stimulable phosphor layer 3 and follows the shape (surface profile) of the surface of the protective layer 2 facing the stimulable phosphor layer 3. Accordingly, the surface of the stimulable phosphor layer 3 facing the protective layer 2 has a high flatness (preciseness of the surface profile) equivalent to that of the surface of the protective layer 2 facing the stimulable phosphor layer 3. The integrated projecting means 20 and detecting means 30 are conveyed in the direction of arrow Y so that the surface profile of the surface of the stimulable phosphor layer 3 facing the protective layer 2 is positioned within the range of the focal depth of the imaging lens 31. Accordingly, the line-like area of the surface of the stimulable phosphor layer 3 which emits stimulated emission can be uniformly imaged on the line sensor 32 and the radiation image information recorded on the stimulable phosphor sheet 1 can be more uniformly and more precisely read out. The mechanism that an air layer formed between the protective layer 2 and the stimulable phosphor layer 3 of the stimulable phosphor sheet 1 increases the amount of stimulated emission which is imaged on the line sensor 32 through the imaging lens 31 will be described, hereinbelow. When the space between the protective layer and the stimulable phosphor layer is filled with liquid to purge air or the protective layer is bonded to the stimulable phosphor layer by adhesive or the like, since the adhesive layer and the liquid are higher than air in refractive index, the optical path of the stimulated emission emitted from the stimulable phosphor layer 93 (FIG. 3) is greatly bent when emanating from the protective layer 92 into the air 95 to provide a large exit angle of α as shown in FIG. 3. To the contrast, when an air layer 94 is formed between the protective layer and the stimulable phosphor layer, the stimulated emission emanates from the protective layer 92 into the air 95 at the same angle as that at which the stimulated emission emanates from the stimulable phosphor layer 93 into the air layer 94 and accordingly, the optical path of the stimulated emission emitted from the stimulable phosphor layer 93 (FIG. 3) is less bent when emanating from the protective layer 92 into the air 95 to provide a relatively small exit angle of β as shown in FIG. 4. In the stimulable phosphor sheet 1 employed in the radiation image read-out apparatus 100 in accordance with the first embodiment of the present invention, the stimulable phosphor layer 3 is actually in contact with the protective layer 2 only at the contact areas R as shown in FIG. 5, and a thin air layer A is formed between the stimulable phosphor layer 3 and the protective layer 2 over the area but the contact areas A, whereby the stimulated emission emitted from the stimulable phosphor layer 3 emanates from the protective layer 2 into the air 95 at an exit angle of β. The exit angle of β is smaller than that α′ at which the stimulated emission emitted from the stimulable phosphor layer 3 would emanate from the protective layer 2 into the air 95 if the air layer A is replaced by adhesive or the like as in the conventional stimulable phosphor sheet. As a result, the amount of the stimulated emission imaged on the line sensor 32 through the imaging lens 31 can be increased. Stimulable phosphor sheets in accordance with various embodiments of the present invention and in accordance with various comparative examples were made in the following manners and these stimulable phosphor sheets were compared with each other in the following manners. Stimulable Phosphor Sheet of a First Embodiment A mixture solution was prepared by dispersing a 20:1 mixture of a stimulable phosphor and a polyurethane resin in solvent. A stimulable phosphor layer was formed by applying the mixture solution to a support and drying the same. Then the stimulable phosphor layer thus obtained was bonded under heat to a support of polyethylene terephthalate provided with an adhesive layer by calendering, thereby obtaining a stimulable phosphor layer/support assembly 40 comprising a support 41 and a stimulable phosphor layer 42 as shown in FIG. 6. The surface roughness Ra of the surface of the stimulable phosphor layer 42 of the stimulable phosphor layer/support assembly 40 was 0.18 μm. Then an abraded rectangular plane plate 50 of soda glass which was 2 mm±20 μm in mean thickness was prepared as a protective layer. A side plate 51 was bonded to the lower side of the plane plate 50 by adhesive along each of four sides thereof so that the four side plates 51 defined a space E at a central portion of the lower side of the plane plate 50 as shown in FIG. 7. Then the stimulable phosphor layer/support assembly 40 was placed in the space E so that the surface of the plane plate 50 facing the space E faced the surface of the stimulable phosphor layer of the stimulable phosphor layer/support assembly 40, and an elastic urethane foam 52 was inserted into the space E so that the urethane foam 52 uniformly pressed the stimulable phosphor layer/support assembly 40 over the entire area thereof from the support side and the entire area of the surface of the stimulable phosphor layer 42 of the stimulable phosphor layer/support assembly 40 was brought into contact with the plane plate 50. Finally, the opening of the space was closed by a bottom plate 53. Stimulable Phosphor Sheet of a Second Embodiment A stimulable phosphor sheet of a second embodiment was made in the same manner as in the first embodiment except the following point. When bonding under heat (calendering) the stimulable phosphor layer 42 to the support 41 in order to make the stimulable phosphor layer/support assembly 40, a metal roller having irregularities on its surface was pressed against the stimulable phosphor layer 42 so that the irregularities on the surface of the metal roller were transferred to the stimulable phosphor layer 42. The metal roller was 2.4 μm in surface roughness (Ra) and 19.8 μm in Rmax. The temperature bonding under heat was 50° C., and the metal roller was pressed against the stimulable phosphor layer 42 at 46 kg/cm (linear pressure). The stimulable phosphor layer 42 thus obtained was 0.35 μm in surface roughness (Ra). Stimulable Phosphor Sheet of a Third Embodiment A soda glass plane plate 50 the same as that employed in the first embodiment was heated to 80° C. and a stimulable phosphor layer/support assembly 40 formed in the same manner as in the first embodiment was bonded to the plane plate 50 under a pressure of 1 kg/cm (linear pressure) by a roller with the surface of the stimulable phosphor layer 42 facing the plane plate 50, thereby obtaining a stimulable phosphor sheet solely comprising a soda glass plane plate 50 and stimulable phosphor layer/support assembly 40 as shown in FIG. 8. In this embodiment, the plane plate 50 could be bonded to the stimulable phosphor layer 42 by binder contained in the stimulable phosphor layer 42. Stimulable Phosphor Sheet of a Fourth Embodiment A stimulable phosphor sheet of a fourth embodiment was made in the same manner as in the third embodiment except that the roller pressure was 10 kg/cm in linear pressure. Stimulable Phosphor Sheet of a Fifth Embodiment A stimulable phosphor layer/support assembly 40 formed in the same manner as in the first embodiment was applied to a soda glass plane plate 50 the same as that employed in the first embodiment by adhesive tape with the surface of the stimulable phosphor layer 42 facing the plane plate 50, thereby obtaining a stimulable phosphor sheet solely comprising a soda glass plane plate 50 and stimulable phosphor layer/support assembly 40 as shown in FIG. 9. Stimulable Phosphor Sheet of a Sixth Embodiment A thermoplastic high polymer polyester resin layer 56 was formed on a soda glass plane plate 50 the same as that employed in the first embodiment as shown in FIG. 10, and a stimulable phosphor layer/support assembly 40 formed in the same manner as in the first embodiment was applied to the polyester resin layer 56 so that the surface of the stimulable phosphor layer 42 is in contact with the resin layer 56 and no air layer is formed between the stimulable phosphor layer 42 and the resin layer 56. Stimulable Phosphor Sheet of a First Comparative Example (Not in Accordance with the Present Invention) A stimulable phosphor sheet of a first comparative example was made in the same manner as in the first embodiment except that a space of 0.2 mm is formed between the plane plate 50 and the stimulable phosphor layer/support assembly 40 instead of inserting a urethane foam 52 in the space E as shown in FIG. 11. The surface profile error (an error against an optimal plane) of the stimulable phosphor layer surface of the stimulable phosphor sheets of the first to sixth embodiments and the first comparative example were as shown in the following table 1. The surface profile error was measured by a non-contact laser displacement meter after the stimulable phosphor sheets were completed. Table 1 further shows the relative performance of the stimulable phosphor sheets of the first to sixth embodiments and the first comparative example. TABLE 1detectedstimulatedcontact betweenemissionsurfacephosphor layer(relativeprofileand protectiveairamount)errorlayerlayer1st embodiment100±40 μmexistexist2nd embodiment102±42 μmexistexist3rd embodiment98±35 μmexistexist4th embodiment94±37 μmexistexist5th embodiment100±43 μmexistexist6th embodiment62±38 μmexistno1st comparative59±102 μm noexistexample The stimulable phosphor sheets of the first to sixth embodiments were all within ±50 μm in surface profile error of the stimulable phosphor layer surface since the stimulable phosphor layer was in contact with the soda glass plane plate and the stimulable phosphor layer surface followed the surface of the plane plate in shape in the stimulable phosphor sheets of the first to sixth embodiments. To the contrast, the stimulable phosphor sheet of the first comparative example, where the stimulable phosphor layer was not in contact with the soda glass plane plate, was ±102 μm in surface profile error of the stimulable phosphor layer surface since the stimulable phosphor layer surface did not follow the surface of the plane plate in shape, and the shape of the surface of the bottom plate, fluctuation in thickness of the support and the stimulable phosphor layer and the like accumulated. Experiment in which stimulated emission emitted from the stimulable phosphor layers of the stimulable phosphor sheets was detected will be described, hereinbelow. Exposure of Each Stimulable Phosphor Sheet to a Radiation With the surface of the soda glass plane plate masked by a lead mask having a slit, a radiation is projected onto each of the stimulable phosphor sheets of the first to sixth embodiments and the first comparative example from the plane plate side, thereby recording a latent image of a line on the stimulable phosphor layer. Reading Out the Line Latent Image from the Stimulable Phosphor Sheet The line latent image was read out by projecting a line stimulating light beam extending in the same direction as the line latent image onto the stimulable phosphor sheet with the lead mask removed therefrom. The result of this experiment will be described with reference to the aforesaid table 1, hereinbelow. In table 1, “detected stimulated emission” is the sum of the amounts of light detected by the respective photoelectric convertor elements forming the line sensor and is expressed in a relative value when that detected from the stimulable phosphor sheet of the first embodiment is taken as 100. In the case of the stimulable phosphor sheets of the first to fifth embodiments, where the stimulable phosphor layer is in contact with the soda glass plane plate and the surface profile error of the stimulable phosphor layer surface is in the range of ±35 μm to ±43 μm and an air layer is formed between the stimulable phosphor layer and the soda glass plane plate, the “detected stimulated emission” was not smaller than 94 and not larger than 102 and was substantially equal to each other. In the case of the stimulable phosphor sheet of the sixth embodiment, where the stimulable phosphor layer is in contact with the soda glass plane plate by way of an adhesive layer and the surface profile error of the stimulable phosphor layer surface is in the range of ±38 μm and no air layer is formed between the stimulable phosphor layer and the soda glass plane plate, the “detected stimulated emission” was 62. As can be understood from the description above, when an air layer was not formed between the stimulable phosphor layer and the soda glass plane plate, the amount of detected stimulated emission was reduced. This is for the reason described above. In the case of the stimulable phosphor sheet of the first comparative example, where the stimulable phosphor layer is not in contact with the soda glass plane plate and the surface profile error of the stimulable phosphor layer surface is in the range of ±102 μm and an air layer is formed between the stimulable phosphor layer and the soda glass plane plate, the “detected stimulated emission” was 59. The reason for the reduction of the amount of detected stimulated emission is that there are some areas positioned outside the focal depth of the imaging lens in the detected surface of the stimulable phosphor layer and accordingly the image of the stimulated emission emitting areas imaged on the line sensor is out of focus, whereby a part of the stimulated emission emitted from the stimulated emission emitting areas misses the line sensor. The result of the experiment described above indicates that the amount of detected stimulated emission will be further reduced in the case of the conventional stimulable phosphor sheets, where Stimulable phosphor sheets, where the stimulable phosphor layer is in contact with the protective layer by way of filler so that a void is formed between the stimulable phosphor layer and the protective layer, will be described hereinbelow. Stimulable Phosphor Sheet of a Seventh Embodiment A stimulable phosphor sheet of a seventh embodiment comprised a stimulable phosphor layer 61 and a protective layer 60 which were in contact with each other by way of filler 63 so that a void was formed between the stimulable phosphor layer 61 and the protective layer 60 as shown in FIG. 12. The filler 63 was positioned on a coating layer 62 formed on one side of the stimulable phosphor layer 61. A reflective layer 64 and a support 65 were superposed on the other side of the stimulable phosphor layer 61 in this order. Stimulable Phosphor Layer 61 As a solution for forming the stimulable phosphor layer 61, the following phosphor and components were added to solvent and a solution of 4 Pa·s was prepared. The solution was applied to a temporary support in a width of 300 mm by a doctor blade and then dried. Thereafter the solution layer thus obtained was peeled off the temporary support and a few stimulable phosphor layers 300 μm thick were made. As the phosphor, 1000 g of a 5:5 blend (by weight) of 14-hedral phosphor (BaFBr0.05I0.15Eu2+) 6 μm in mean diameter (Dm) and that 3 μm in mean diameter was used. As the aforesaid components, the following materials were employed. binder: 182 g, obtained by dissolving polyurethane elastomer (PANDEX T-5265H[solid]; Dainippon Ink And Chemicals Inc.) in methyl ethyl ketone to a solid content concentration of 13 wt % cross-linking agent: 3 g, polyisocyanate (Coronate HX [100% solid content], Nippon Polyurethane Industries Co., Ltd.) anti-yellow-discoloration agent 6.7 g, epoxy resin (Epikote #001[solid], Japan Epoxy Resins Co., Ltd. coloring agent: 0.02 g, (ultramarine, SM-1, Daiichi kase kogyo Co., Ltd.) As the solvent, 47 g of methyl ethyl ketone was employed. As the temporary support, a polyethylene terephthalate sheet coated with a silicone release agent (190 μm thick) was employed. These components were dispersed for thirty minutes at 10000 rpm by the use of a propeller mixer and a solution for forming the stimulable phosphor layer whose binder/phosphor ratio was 1/20 by weight was obtained. Support with a Reflective Layer Powder materials and solvent were added to a binder and a solution 2 to 3 Pa ·s in viscosity was obtained. The solution was applied to a support (a polyethylene terephthalate sheet, Lumillar S-10, Toray Inc., 188 μm in thickness, 27 in typical haze) in a thickness of 100 mm, thereby obtaining a support with a reflective layer comprising a support provided with a reflective layer which was a conductive prime-coating layer. As the binder, 100 g of soft acrylic resin (CRISCOAT P-1018GS[20% toluene solution]; Dainippon Ink And Chemicals Inc.) was employed. As the powder material, 444 g of reflective material (high-purityalumina, UA-5105, Showa Denko) and 2.2 g of coloring agent (ultramarine, SM-1, Daiichi kasei kogyo Co., Ltd.) were employed. As the solvent, 387 g of methyl ethyl ketone was employed. Production of Stimulable Phosphor Layer/Support Assembly by Hot-pressing the Stimulable Phosphor Layer and the Support with a Reflective Layer Several stimulable phosphor layer/support assemblies (indicated at T in FIG. 13) comprising a stimulable phosphor layer 61 and a support with a reflective layer comprising a support 65 provided with a reflective layer 64 which was a conductive prime-coating layer as shown in FIG. 13 were produced by the use of a calendering machine under the following conditions. Calendering Conditions The stimulable phosphor layer 61 was superposed on the reflective layer 64 of the support with a reflective layer. At this time, calendering was done with the stimulable phosphor layer 61 superposed on the support with a reflective layer so that the surface of the stimulable phosphor layer facing the temporary support when producing the stimulable phosphor layer 61 was faced toward the reflective layer of the assembly under the following conditions. Total load: 23 tons, upper roller temperature: 45° C., lower roller temperature: 45° C., feed rate: 0.3 m/min. By thermocompression by the calendering, the stimulable phosphor layer was completely welded to the support by way of the reflective layer 64 which was a conductive prime-coating layer, whereby stimulable phosphor layer/support assemblies were formed. The packing density of the phosphor on the stimulable phosphor layer was 3.40 g/cm3. Lamination of the Stimulable Phosphor Layer/Support Assembly on the Coating Layer 62 where the Filler 63 was Fixed Components to be described later were added to solvent and a coating solution was prepared. The coating solution thus prepared was applied to the stimulable phosphor layer surface of the stimulable phosphor layer/support assembly made by calendering to form a coating layer 2 μm thick. Then the assembly was cut into pieces of 200 mm×250 mm, thereby obtaining stimulable phosphor layer/support assemblies with a coating layer with filler which comprised a support 65, a reflective layer 64, a stimulable phosphor layer 61 and a coating layer 62 with filler 63 superposed one on another in this order as shown in FIG. 14. As the aforesaid components, the following materials were employed. fluoroplastic (fluoroolefin-vinyl ether copolymer, Lumiflon LF-504X [30% xylene solution], Asahi Glass Inc.): 76 g cross-linking agent: 7.5 g (polyisocyanate, Sumidur N3500 [100% solid content], Sumitomo Bayer Urethane Co., Ltd.) organic filler: 11 g (melamine-formaldehyde, Epostar S12 (mean particle diameter=1.2 μm), Nippon Shokubai Co., Ltd.) coupling agent: 0.1 g (acetoalcoxy aluminum diisopropylate, Plenact AL-M, Ajinomoto Inc.) catalyst: 0.25 g (dibutyltindilaurate, KS1260, Kyodo Chemical) As the solvent, 38 g of methyl ethyl ketone was employed. Since the coating solution coated on the stimulable phosphor layer/support assembly was dried and fixed with the organic filler therein floating to the surface of the solution, the coating layer had irregularities formed by the organic filler. Lamination of a Glass Plate (Protective Layer) on the Stimulable Phosphor Layer/Support Assembly with a Coating Layer An abraded soda glass plate which was 2 mm±20 μm in mean thickness was prepared as a protective layer. Then the stimulable phosphor layer/support assembly with a coating layer including therein filler was laminated on the protective layer with the coating layer in contact with the protective layer and fixed to the protective layer along its four sides by Mylar tape, thereby obtaining a stimulable phosphor sheet of the seventh embodiment shown in FIG. 12. In this stimulable phosphor sheet, the stimulable phosphor layer 61 was laminated on the protective layer 60 intervening therebetween filler 63 so that a void Q was formed between the stimulable phosphor layer 61 and the protective layer 60. The stimulable phosphor layer/support assembly with a coating layer including therein filler may be bonded to the protective layer by superposing the assembly on the protective layer with the coating layer in contact with the protective layer and passing them through laminating rolls whose surface temperatures are 90° C. Stimulable Phosphor Sheet of an Eighth Embodiment A stimulable phosphor sheet of an eighth embodiment comprised a second coating layer 66 formed on a protective layer 60 (a protective layer/second coating layer assembly indicated at V in FIG. 15) and a stimulable phosphor layer/support assembly with a first coating layer including therein filler (indicated at W in FIG. 15) as produced in the manner described above in conjunction with the seventh embodiment. The former was laminated on the former with the first and second coating layers opposed to each other. Formation of the Second Coating Layer 66 on the Protective Layer 60 and Production of the Stimulable Phosphor Sheet A stimulable phosphor sheet of an embodiment 8-1 was produced in the following manner. A binder solution was applied in a thickness of 2 μm to an abraded soda glass plate which was 2 mm±20 μm in mean thickness, there by preparing a protective layer with a second coating layer. Then the protective layer with a second coating layer was bonded to a stimulable phosphor layer/support assembly with a first coating layer including therein filler with the first and second coating layers opposed to each other. A stimulable phosphor sheet of an embodiment 8-2 was produced in the following manner. A binder solution was applied in a thickness of 2 μm to an abraded soda glass plate which was 2 mm±20 μm in mean thickness to form a binder layer, and further applied to the binder layer to a thickness of 5 μm, thereby preparing a protective layer with a second coating layer. Then the protective layer with a second coating layer was bonded to a stimulable phosphor layer/support assembly with a first coating layer including therein filler with the first and second coating layers opposed to each other, thereby obtaining a stimulable phosphor sheet of an embodiment 8-2. As the binder solution, 10 g of a solution obtained by dissolving Vylon 300 (unsaturated polyester resin made by Toyobo Inc.) in MEK [15 wt % solid content] was employed. The stimulable phosphor layer/support assembly with a first coating layer including therein filler may be bonded to the protective layer with a second coating layer by superposing the former on the latter with the coating layers opposed to each other and passing them through laminating rolls whose surface temperatures are 90° C. Stimulable Phosphor Sheet of a Ninth Embodiment A stimulable phosphor sheet of a ninth embodiment comprised a second coating layer 67 with filler formed on a protective layer 60 (a protective layer/second coating layer assembly with filler indicated at U in FIG. 16) and a stimulable phosphor layer/support assembly with a first coating layer including therein filler (indicated at W in FIG. 16) as produced in the manner described above in conjunction with the seventh embodiment. The former was laminated on the former with the first and second coating layers opposed to each other. Formation of the Second Coating Layer 66 on the Protective Layer 60 and Production of the Stimulable Phosphor Sheet A stimulable phosphor sheet of an embodiment 9-1 was produced in the following manner. An adhesive solution with filler (a mixture of an adhesive solution, organic filler and solvent) was applied in a thickness of 2 μm to an abraded soda glass plate which was 2 mm±20 μm in mean thickness, thereby preparing a protective layer with a second coating layer with filler. Then the protective layer with a second coating layer with filler was bonded to a stimulable phosphor layer/support assembly with a first coating layer including therein filler with the first and second coating layers opposed to each other. A stimulable phosphor sheet of an embodiment 9-2 was produced in the following manner. The same adhesive solution was applied in a thickness of 2 μm to an abraded soda glass plate which was 2 mm±20 μm in mean thickness to form an adhesive layer, and further applied to the adhesive layer to a thickness of 5 μm, thereby preparing a protective layer with a second coating layer. Then the protective layer with a second coating layer with filler was bonded to a stimulable phosphor layer/support assembly with a first coating layer including therein filler with the first and second coating layers opposed to each other, thereby obtaining a stimulable phosphor sheet of an embodiment 9-2. Since the second coating layer formed by the adhesive solution has adhesion, the former and the latter can be bonded without use of additional adhesive material. As the adhesive solution, 10 g of a solution obtained by dissolving Vylon 300 (unsaturated polyester resin made by Toyobo Inc.) in MEK [15 wt % solid content] was employed. As the organic filler, 10 g of EPOSTAR S12 (mean particle diameter=1.2 μm, melamine-formaldehyde, Nippon Shokubai Co., Ltd.) was employed. As the solvent, 20 g of methyl ethyl ketone was employed. The stimulable phosphor layer/support assembly with a first coating layer including therein filler may be bonded to the protective layer with a second coating layer with filler by superposing the former on the latter with the coating layers opposed to each other and passing them through laminating rolls whose surface temperatures are 90° C. Stimulable Phosphor Sheet of a Tenth Embodiment A stimulable phosphor sheet of a tenth embodiment was made in the same manner as in the seventh embodiment except that 22 g of inorganic filler (alumina particles 2 μm in mean particle diameter: Sumicorundum AA-2, Sumitomo Chemical Inc.) was employed in place of organic filler. Stimulable Phosphor Sheet of an Eleventh Embodiment A stimulable phosphor sheet of an eleventh embodiment was made in the same manner as in the seventh embodiment except that 22 g of micro glass beads (5 to 7 μm in mean particle diameter: MB-10, Toshiba-Ballotini Inc.) was employed. Stimulable Phosphor Sheet of a Second Comparative Example A stimulable phosphor sheet of a second comparative example was produced. The stimulable phosphor sheet of a second comparative example comprised a second coating layer 66 without filler formed on a protective layer 60 (a protective layer/second coating layer assembly without filler indicated at V in FIG. 17) and a stimulable phosphor layer/support assembly with a first coating layer without filler (indicated at T in FIG. 17) as produced in the manner described above in conjunction with the eighth embodiment. The former was laminated on the former with the first and second coating layers opposed to each other. In this example, the stimulable phosphor layer/support assembly with a first coating layer and the protective layer/second coating layer assembly were in optical contact with each other. Stimulable Phosphor Sheet of a Third Comparative Example A stimulable phosphor sheet of a third comparative example was produced in the following manner. A stimulable phosphor layer/support assembly formed in the seventh embodiment (indicated at T in FIG. 13) was separated between the reflective layer 64 and the stimulable phosphor layer 61 and only a stimulable phosphor layer was taken as a stimulable phosphor sheet of the third comparative example. Evaluation Production of Evaluation Samples The stimulable phosphor sheets of the seventh to eleventh embodiments and second and third comparative examples were separated between the reflective layer and the stimulable phosphor layer and the stimulable phosphor layer side piece of each stimulable phosphor sheet was taken as the evaluation sample. Measurement of the Evaluation Samples He—Ne laser beam Le was caused to impinge upon each evaluation sample from the side of the stimulable phosphor layer 61 and a peak intensity Ip in an intensity profile P of the laser beam Le emanating from the evaluation sample through the protective layer 60 was measured as shown in FIG. 18. A peak intensity Io in an intensity profile P of the laser beam Le was measured without any sample. Then a peak intensity ratio I(=Ip/Io), that is, the ratio of the peak intensity obtained with the evaluation sample to that obtained without any evaluation sample was calculated. The result was as shown in the following table 2. TABLE 2embodimentI (=Ip/Io)Ra of coating layer with filler76.50%8-16.30%1st coating layer: 0.6 μm8-24.50%1st coating layer: 0.6 μm9-16.50%1st coating layer: 0.6 μm2nd coating layer: 0.5 μm9-25.30%1st coating layer: 0.6 μm2nd coating layer: 0.2 μm106.40%coating layer: 0.8 μm116.40%coating layer: 0.3 μm1st comparative3.20%—example2nd comparative7.70%—example As can be understood from table 2, in the evaluation sample of the second comparative example, where the stimulable phosphor layer and the protective layer were in optical contact with each other, there was a great reduction of the peak intensity ratio as compared with the third comparative example solely consisting of stimulable phosphor layer. To the contrast, in the evaluation samples of the seventh to eleventh embodiments, the reduction of the peak intensity ratio was smaller. That is, in the evaluation sample of the third comparative example consisting solely of the stimulable phosphor layer 61, the laser beam emanating therefrom diverges as indicated by K1 in FIG. 19A. To the contrast, in the evaluation sample of the second comparative example, where the stimulable phosphor layer and the protective layer were in optical contact with each other, the laser beam emanating therefrom is greatly refracted in the direction parallel to the surface of the protective layer to diverge more widely as indicated by K2 in FIG. 19B, which results in a great reduction of the peak intensity ratio. In the evaluation samples of the seventh to eleventh embodiments, where the stimulable phosphor layer 61 is in contact with the protective layer 60 by way of filler so that a void is formed therebetween, the laser beam emanating therefrom is less refracted in the direction parallel to the surface of the protective layer to diverge less widely as indicated by K3 in FIG. 19C, which results in a smaller reduction of the peak intensity ratio. The surface roughness Ra of the layer added with a spacer such as filler is preferably in the range of about 0.2 to 20 μm, and more preferably in the range of about 0.5 to 5 μm.
	abstract	Systems, devices, and methods for filling containers with radioactive materials are described. In certain embodiments, the systems comprise a shielding material that substantially defines a chamber and, preferably, substantially blocks radioactivity, a conduit extending through the shielding material into the chamber, and a securing unit that is disposed in the chamber proximal to the conduit and is adapted to receive a container through the conduit.
	summary
	summary
052992527	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS An description of embodiment of a fluorescent X-ray film thickness measuring apparatus according to the present invention will be provided below with reference to the drawing. Referring to FIG. 1, primary X-rays a generated by an X-ray tube 1 are collimated in the form of a beam by means of a collimator 2 having a rectangular opening, or aperture. The beam is directed through a sample observing mirror 3 to irradiate a sample 5 mounted on an automatic X-Y sample stage 4. An X-ray detector 6 detects fluorescent X-rays b emitted from sample 5 in response to excitation by the primary X-rays and the output thereof is processed by a succeeding signal processing system (not shown) and converted into a film thickness indication. The shape of the sample 5 is monitored, through the mirror 3, with the aid of a television camera 7 and a cathode ray tube (CRT) 8, and is displayed on the CRT 8. At the same time, the image of a reticle 9 is superposed on the sample image through a half mirror, or semitransparent mirror, 10 and is displayed on the CRT 8. Cross lines showing the direction of the aperture of collimator 2 and an outline showing the shape of the aperture of collimator 2 are etched on the reticle 9. Collimator 2 is mounted to be rotated about an axis which passes through the geometric center of the rectangular aperture and which is parallel to the axis of the collimated primary X-ray beam by means of a collimator drive motor 11. Similarly, a reticle drive motor 12 rotates reticle 9 about an axis perpendicular to the cross lines and passing through the point of intersection of the cross lines. A motor controller 13 controls the collimator drive motor 11 and the reticle drive motor 12 so as to rotate them by the same angle. The optical system consisting of the mirror 3, the reticle 9, the half mirror 10, and the television camera 7 is adjusted so as to match the center position of the primary X-ray beam on the automatic X-Y sample stage 4 with the intersection of the cross lines of reticle 9 displayed on the CRT 8. Furthermore, the direction of the long dimension of the cross section of the primary X-ray beam, defined by the outline of the aperture in collimator 2, is matched with the direction, at that time, of the cross lines displayed on the CRT 8, by adjusting the angular orientation of the reticle 9 and the angular orientation of the collimator 2. In the fluorescent X-ray film thickness measuring apparatus thus composed and adjusted, when the thickness of an elongated sample portion is measured, the automatic X-Y sample stage 4 carrying the sample 5 is moved to align the portion being measured thereof with the intersection of the cross lines. Next after rotating the collimator 2 to align the collimator image or cross lines displayed on the CRT 8 with the desired direction of the portion being measured, a film thickness measurement may be started. FIG. 2 shows an embodiment functionally similar to that of FIG. 1. In FIG. 2, a cross line generator 14 which electronically produces cross lines and a collimator aperture image is used to produce the desired display on CRT 8, instead of reticle 9, half mirror 10, and reticle drive motor 12 shown in FIG. 1. The above fluorescent X-ray film thickness measuring apparatus includes a rectangular aperture collimator which can be stopped at an arbitrary angle within a range of 180.degree. and around the center of the aperture. Furthermore since a sample observing device can confirm the angular orientation of the collimator, a positioning procedure can be easily achieved with respect to an elongated portion to be measured extending in an arbitrary direction on a sample. As described above, according to the present invention, the rectangular collimator can rotate around the axis of a primary X-ray beam and stop at a desired position. Furthermore the direction of the long side of the rectangle can be confirmed using a sample observing device. Hence this structure can position the elongated measuring portion in a desired direction and has the effect of facilitating its orienting procedure. This application relates to subject matter disclosed in Japanese application number U4-21183, filed on Apr. 7, 1992, the disclosure of which is incorporated herein by reference. While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
052316548	abstract	A collimator for use in an imaging system with a radiation point source has a plurality of channels formed therein along longitudinal axes aligned with selected orientation angles that correspond to the direct beam path from the radiation source to the radiation detectors. The collimator comprises a photosensitive material coated with a radiation absorbent material. The cross-sectional shape of the channels corresponds to the cross-sectional shape of the radiation detecting area of the detector element adjoining the channel, and the sidewalls of the channel are smooth along their length. The collimator may be fabricated by forming a mask on a photosensitive collimator substrate, exposing the photosensitive substrate to light beams traveling along a path corresponding to a direct path of radiation from the radiation source to the detector elements in the assembled array, etching the collimator substrate to form channels therein along the exposed area of the substrate, and coating the substrate with a radiation absorbent material.
055984495	summary	TECHNICAL FIELD This invention relates to a synthesis of, for example, .sup.13 N-ammonia which is a labeled compound used in the PET system, or the like. BACKGROUND ART The PET (Position Emission Tomography) is utilized as a method of diagnosing the diseased part by injecting a emission radioactive isotope into the body of a patient and measuring .alpha.-rays emitted from positron released from the isotope to determine the distribution of the radioactive isotope at each slice. As the synthesis of the radioactive isotope, for example, a synthesis of pyruvate-1-.sup.11 C is disclosed in Japanese Patent KOKAI No. 1-294639. In this method, .sup.11 CO.sub.2 is produced by a cyclotron, and the exchange reaction occurs between the .sup.11 CO.sub.2 and non-radioactive pyruvate. In the synthesis, syringes are utilized for the injection of NaOH, transfer of a substrate solution and the like, but it is not disclosed at all to check whether these reagent solutions are sufficiently sucked into the syringe or not. As the producing technique of .sup.13 N-ammonia, it is known to use the apparatus shown in FIG. 7 (RADIOISOTOPES, vol. 30, pp 1-6, 1981). In the method of producing .sup.13 N-ammonia using the apparatus, a fixed amount of target water is charged into an irradiation cell 8 through a three way cock 27 and a two way cock 28. Subsequently, the cock 27 is changed over, the whole amount of the target water remaining in a liquid feed pipe 30 is put into the irradiation cell 8 by using pressurized helium gas or nitrogen gas as the carrier gas. At that time, the carrier gas is discharged from pipe 32 by opening cock 31. Then, cock 27, cock 28 and cock 31 are closed, and when proton beam is irradiated, oxygen atoms in the target water reacts to produce .sup.13 N through nuclear reaction. The nitrogen atoms react with surrounding oxygen atoms to produce .sup.13 N-nitrate ions (.sup.13 N--NO.sub.3.sup.-). Subsequently, the target water to which the irradiation is finished is put into reaction vessel 35 by opening cock 34 and then cock 27 and cock 28. Then, reagent TiCl.sub.3 in vial 38 is put into the reaction vessel 35 by opening cock 36 and cock 37. Reagent NaOH in vial 41 is further put into the reaction vessel 35 by opening cock 39 and cock 40. Subsequently, .sup.13 N-nitrate ions are allowed to react to be converted to .sup.13 -ammonia by heating the reaction vessel by heater 42. The ammonia is recovered into vial 45 through pipe 43 by distillation. In the past, .sup.13 N-ammonia was produced as stated above. Since water was also distilled and condensed in the vial 45, an isotonic liquid usable for injection was obtained by measuring the amount of the water therein and adding sodium chloride which was weighed according to the amount. It is not disclosed to utilize a syringe for the injection of liquid in the apparatus. In the above producing method of .sup.13 N-ammonia, since .sup.13 N-nitrate ion is converted to .sup.13 N-ammonia, distilled and then purified it, a long time is necessary for obtaining it. Particularly, heating takes time due to distillation operation. As a result, more than 10 minutes are necessary from the end of the irradiation to taking out the produced .sup.13 N-ammonia into the vial 45. Since the half lifetime of .sup.13 N- is short, i.e. 9.96 minutes, about a half of .sup.13 N was lost by the decay in the meantime. Besides, since sodium chloride was weighed and added separately, it was also a problem that the operation was complex and troublesome and that the sodium chloride concentration was scattered. Incidentally, as the means to charge a constant amount of a reagent solution or the like into a separate container automatically, there are the syringe method and the vial method. In the syringe method, a necessary amount of liquid is previously put in a syringe, and at the time of need, the piston of the syringe is depressed to charge it, and the method is disclosed in RADIOISOTOPE, vol. 33, pp 706-709, 1984, Eizo Joho (Image Information), 3, 1981, etc. In the vial method, a necessary amount of liquid is previously put in a vial, and at the time of need, the whole amount is delivered by pressurized He, N.sub.2, etc. gas, and the method is disclosed in Int. Appl. Radiat. Isot., vol. 36, No. 6, pp 469-474, 1985, ibid., vol. 35, No. 6, pp 445-454, 1984, etc. In the syringe method, when liquid is sucked into the syringe, if there is clogging in the pipe, defective connection of the pipe, breakage of the pipe or the like, the sucked amount of the liquid into the syringe is short. In the conventional automatic synthesis apparatus, the procedure automatically proceeded to the next process even in such a case, and troubles occurred, because of lacking any checking function thereof. Furthermore, waiting for a certain period is necessary at the time of sucking the liquid into the syringe. Besides, even in the case of using the same liquid, vials or syrings as many as the number of using it must be set, irrespective of the vial method or the syringe method. The present invention has been achieved in order to solve the above problems, and an object of the invention is to provide a method capable of synthesizing .sup.13 N-ammonia in a short time by lasy operations. Another object of the invention is to provide a means capable of preventing troubles by checking whether the necessary amount of liquid has been sucked into the syringe or not. A further object of the invention is to provide a means capable of preventing troubles by checking whether the necessary amount of liquid has been sucked into the syringe or not. A further object of the invention is to provide a means capable of omitting the waiting time at the time of sucking into the syringe and operating in a short time. This invention is particularly effective in the case of using a radioactive isotope having a short half lifetime, such as .sup.13 N. DISCLOSURE OF INVENTION The above objects have been achieved by a process for the synthesis of .sup.13 N-ammonia in target which comprises charging target water and hydrogen into a synthesis apparatus to make a pressurized condition at 0.1-5 kg/cm.sup.2 and irradiating proton beam to the circulating target water to produce .sup.13 N-ammonia. The above objects have also been acieved by a process for the synthesis of .sup.13 N-ammonia in target which comprises bringing target water containing .sup.13 N-ammonia produced by charging target water and hydrogen and irradiating proton beam into contact with a Na-type cation-exchange resin to collect .sup.13 N-ammonia by the cation-exchange, and then bringing the cation-exchange resin into contact with a saline solution to elute the collected .sup.13 N-ammonia into the saline solution. The above objects further have been achieved by a process for the synthesis of a labeled compound containing a process of injecting a liquid into a vessel which has characteristics as follows: At the time of sucking a prescribed amount of the liquid from a tank thereof into a syringe and injecting the liquid from the syringe into said vessel, the piston of the syringe is depressed in the state that the pipe connecting the syringe with the vessel has been once closed to detect the displacement of the piston. In the case that the displacement exceeds a prescribed value, the sucked amount of the liquid into the syringe is judged being short. On the other hand, in the case that the displacement is not more than the prescribed value, the pipe is opened to inject the liquid into the vessel.
	description	This disclosure relates generally to ion implanters, and more specifically to predicting dose repeatability for an ion implantation of a substrate. Ion implantation is a standard technique for introducing conductivity-altering impurities into workpieces such as semiconductor wafers (referred to hereinafter as substrates). In a conventional beamline ion implanter, an ion source generates an ion beam and extraction electrodes extract the beam from the source. An analyzer magnet receives the ion beam after extraction and filters selected ion species from the beam. The ion beam passing through the analyzer magnet then enters an electrostatic lens comprising multiple electrodes with defined apertures that allow the ion beam to pass through. By applying different combinations of voltage potentials to the multiple electrodes, the electrostatic lens can manipulate ion energies. A corrector magnet shapes the ion beam generated from the electrostatic lens into the correct form for deposition onto the substrate. A deceleration stage comprising a deceleration lens receives the ion beam from the corrector magnet and further manipulates the energy of the ion beam before it hits the substrate. As the beam hits the substrate, the ions in the beam penetrate the surface of the substrate coming to rest beneath the surface to form a region of desired conductivity. In semiconductor manufacturing, a beamline ion implanter often has to process many batches of substrates based on various recipes. For batches of substrates processed with a common recipe, it is critical that the ion implanter maintain a consistent ion beam output so that it can deliver a desired dose of ions at the chosen energy and incident angle into the surface of each substrate. Dose repeatability which is a measurement indicative of the ability of an ion implanter to generate a batch of substrates each containing a dose of ions at the chosen energy and incident angle that matches the dose of ions found on the other substrates in the batch. Because the optimal combination of settings for beamline elements (e.g., ion source, extraction electrodes, analyzer magnet, first deceleration stage, corrector magnet, second deceleration stage, etc.) may change from setup to setup due to variations in source conditions or changes in the beamline surface conditions that arise over time, it becomes difficult to obtain an ion implantation for a batch of substrates with a dose repeatability that is satisfactory for the implantation. Consequently, some substrates in the batch may end up having undesired conductivity which can lead to scrapping of the substrates. Currently, there are no approaches that enable ion implanters to predict dose repeatability for ion implantations. In a first embodiment, there is a method for predicting dose repeatability for an ion implantation. In this embodiment, the method comprises tuning an ion source to generate an ion beam with desired beam current; obtaining beam current measurements from the tuned ion beam; and predicting the dose repeatability for the ion implantation as a function of the beam current measurements. In a second embodiment, there is a method for controlling an ion implantation of a substrate according to predicted dose repeatability. In this embodiment, the method comprises tuning an ion source to generate an ion beam suitable for performing the ion implantation of the substrate; obtaining beam current measurements from the tuned ion beam; determining the predicted dose repeatability for the ion implantation as a function of the beam current measurements; and controlling the ion implantation of the substrate as a function of the predicted dose repeatability. In a third embodiment, there is a system for predicting dose repeatability for an ion implantation of a substrate. In this embodiment, the system comprises a tuner configured to tune an ion source to generate an ion beam suitable for performing the ion implantation of the substrate. A beamline monitor is configured to obtain beam current measurements from the tuned ion beam. A controller is configured to predict the dose repeatability for the ion implantation as a function of the beam current measurements obtained by the beamline monitor. In a fourth embodiment, there is an ion implanter. In this embodiment, the ion implanter comprises an ion source configured to generate an ion beam. A magnet is configured to bend the path of the ion beam. An end station is configured to receive the ion beam from the magnet for ion implantation of a substrate within the end station. A controller is configured to control the ion implantation of the substrate as a function of predicted dose repeatability, wherein the controller predicts dose repeatability from beam current measurements obtained from the ion beam after tuning of the ion source. In a fifth embodiment, there is a computer-readable medium storing computer instructions, which when executed by a computer system enables an ion implanter to control an ion implantation of a substrate according to predicted dose repeatability. In this embodiment, the computer instructions comprise: tuning an ion source to generate an ion beam suitable for performing the ion implantation of the substrate; obtaining beam current measurements from the tuned ion beam; predicting the dose repeatability for the ion implantation as a function of the beam current measurements; and controlling the ion implantation of the substrate as a function of the predicted dose repeatability. FIG. 1 shows a schematic top view of an ion implanter 100 according to one embodiment of the disclosure. The ion implanter 100 comprises an ion source 102, such as a plasma source, controlled by a controller 104. The ion source 102 generates a stream of charged particles, known as an ion beam 103. Extraction electrodes 106 receive the ion beam 103 from the ion source 102 and accelerate positively charged ions within the beam leaving the source 102. An analyzer magnet 108, such as a 90° deflection magnet, receives the ion beam 103 after positively charged ions have been extracted from the source 102 and accelerates and filters unwanted species from the beam. In particular, as the ion beam 103 enters the analyzer magnet 108, a magnetic field directs the ion species into circular paths. Heavier ions will have larger radii of curvature and strike the outer wall of the analyzer magnet 108; lighter ions have smaller radii of curvature and will strike the inner wall of the magnet. Only ions having the needed mass-to-charge ratio will pass through the analyzer magnet 108. The ion beam 103 passing through the analyzer magnet 108 then enters an electrostatic lens 110, which includes a mass slit 112 which further removes unwanted ions (ion masses) from the beam and multiple electrodes (not shown) with defined apertures to allow the ion beam to pass therethrough. A corrector magnet 114, such as a 45° degree corrector magnet, collimates the ion beam 103 generated from the electrostatic lens 110 into the correct form for deposition onto a substrate 116 such as a semiconductor wafer. Although not shown, a deceleration stage comprising a deceleration lens can receive the ion beam 103 from the corrector magnet 114 and further manipulate the energy of the beam before it enters a vacuum chamber 118 and hits the substrate 116. A substrate handling chamber 120 loads the substrate 116 in the vacuum chamber 118 so that the substrate can undergo the ion implantation operation. The substrate handling chamber 120 uses a transport mechanism 122 such as load lock to remove a substrate from a loading cassette 124 or substrate holder and introduces it to the vacuum chamber 118 for ion implantation. In particular, the transport mechanism 122 places the substrate 116 in the vacuum chamber 118 in the path of the ion beam 103 such that the beam hits the substrate, causing the ions in the beam to penetrate the surface of the substrate and come to rest beneath the surface to form a region of desired conductivity. After completing the processing of the substrate 116, another transport mechanism 126 transports the substrate from the vacuum chamber 118 back to a processed cassette 128 or substrate holder. The vacuum chamber 118, substrate handling chamber 120, transport mechanism 122, loading cassette 124, transport mechanism 126 and substrate holder 128 are collectively referred to hereinafter as an end station. This process of loading, processing, removing and storing substrates continues at the end station until all of the substrates in the loading cassette have undergone the ion implantation operation. For ease of illustration, FIG. 1 only shows those beamline elements of the ion implanter 100 that facilitate a general understanding of the approach described in the disclosure (i.e., predicting dose repeatability and controlling the ion implantation according to the predicted dose repeatability). Those skilled in the art will recognize that the ion implanter 100 can have additional components not shown in FIG. 1. Furthermore, those skilled in the art will recognize that the approach described herein for predicting the dose repeatability and controlling the ion implantation according to the predicted dose repeatability is suitable for any type of ion implanter such as a high current implanter, a medium current implanter or a high energy implanter. The individual elements may change between these different ion implanters but the approach described herein is still generally applicable. Furthermore, this approach for predicting the dose repeatability and controlling the ion implantation according to the predicted dose repeatability is suitable for spot beams or a ribbon beams. Because the optimal combination of settings for beamline elements for the ion implanter 100 may change from setup to setup due to variations in source conditions or changes in the beamline surface conditions that arise over time, it becomes necessary to tune the ion implanter 100 in order to deliver desired beam characteristics. Generally, an ion implanter is tuned to deliver maximum ion beam current which translates into higher machine throughput. Tuning typically begins by finding previously used beamline element settings that will produce a beam output that most closely matches the maximum ion beam current desired by the operator of the implanter. Each of the beamline element settings is then sequentially changed one at a time through different sets of values until a value is found for that beam element that provides a maximum ion beam current. Note that the beamline element settings can be changed in combination and are not limited to making sequential changes. After all of the beam elements have been tuned to deliver maximum ion beam current, beam tuning is deemed to be complete so that the ion implanter can initiate ion implantation operations. Moreover these new settings for the beamline elements are stored for future setups. Instead of tuning for maximum ion beam current, the approach described herein tunes the ion beam to what is specified to be implanted on the substrate 116. In particular, the approach described herein tunes the ion source 102 for both beam quantity and quality by tuning for a statistically expected implant that projects how good the implant will be in the form of statistical estimates. More specifically, the approach tunes for both beam quantity and quality by first tuning the ion source 102 for desired beam current along the beamline and then using the derived statistical estimates (which are indicative of the predicted dose repeatability) as a metric to examine the beam in the end station under real operating conditions. Tuning for both beam quantity and quality in the beamline and using the derived statistical estimates as a metric to examine the beam in the end station under real operating conditions, results in an approach that enables the ion implanter 100 to be externally focused to attain the desired implant. In one embodiment, the process of tuning the ion source 102 is facilitated by using a setup cup 130 located in the beamline of the ion implanter 100 as shown in FIG. 1. The setup cup 130 is essentially a Faraday cup that measures the cumulative ion dose in the ion beam 103. In particular, the setup cup 130 receives the ion beam 103 and produces an electrical current in the cup that is representative of ion beam current. The setup cup 130 supplies the electrical current to an electronic dose processor 132, which integrates the current with respect to time to determine the cumulative ion dose. As shown in FIG. 1, the setup cup 130 is located at the end of the electrostatic lens 110, at the end of the corrector magnet 114 and in the end station (i.e., in the vacuum chamber 118 behind where the substrate is loaded). Those skilled in the art will recognize that the location of the setup cup 130 is not limited to the electrostatic lens 110, the corrector magnet 114 and the vacuum chamber 118. In particular, the setup cup 130 can be located about only one of these elements or it may be desirable to place multiple setup cups 130 at other locations along the beamline to monitor beam current at locations that include but are not limited to the electrostatic lens 110, the corrector magnet 114 and the vacuum chamber 118. In one embodiment of operation, the setup cup 130 receives the ion beam 103 and produces an electrical current in the cup that is representative of ion beam current generated by the ion source 102. The setup cup 130 supplies the electrical current to the electronic dose processor 132, which integrates the current with respect to time to determine the cumulative ion dose. The dose processor 132 supplies the ion dose determination to the controller 104 which ascertains whether the ion beam contains the desired beam current for the implantation of the substrate 116. The controller 104 tunes the ion source 102 until it determines that the predicted dose repeatability for the ion source is suitable for the ion implantation. Below are additional details on how the controller 104 tunes the ion source 102 and determines whether the predicted dose repeatability for the source is suitable for the ion implantation of the substrate 116. Referring back to FIG. 1, a profiling Faraday cup 134 is attached to a shaft 136 which is driven by a motor (not shown). In operation, the motor drives the profiling Faraday cup 134 through the ion beam directed into the vacuum chamber 118. The ion beam 103 passes through the profiling Faraday cup 134 and produces an electrical current in the cup that is representative of ion beam current. The profiling Faraday cup 134 supplies the electrical current to the electronic dose processor 132, which integrates the current with respect to time to determine the cumulative ion dose. Note that it is also possible for the profiling Faraday cup 134 to be used to perform the function of the setup cup 130. The dose processor 132 supplies the ion dose determination to the controller 104 which ascertains whether ion beam generated by the ion source 102 will result in a predicted dose repeatability that is suitable for the ion implantation of the substrate 116. If the dose repeatability is not sufficient, then the controller 104 tunes the ion source 102 within the end station for lower beam noise and/or current. Alternatively, if the dose repeatability is sufficient for the ion implantation, then the controller 104 enables the ion source 102 to begin the ion implantation in the end station. Below are additional details on how the controller 104 determines whether the predicted dose repeatability for the source is suitable for the ion implantation of the substrate 116, tunes the ion source 102 into the end station, and controls the ion implantation according to the dose repeatability. FIG. 2 shows a more detailed view of the controller 104 shown in FIG. 1. As shown in FIG. 2, the controller 104 comprises a beamline element settings controller 200 configured to provide beamline element settings for generating the desired beam current and any other beam properties (e.g., angular distribution, beam density distribution and beam profile uniformity). The beamline settings controller 200 has the capability to interface with the hardware and controls the operation of the hardware settings of the ion implanter 100. In one embodiment, the beamline element settings controller 200 selects initial beamline element settings from a historical database (not shown). The historical database comprises a number of entries that include combinations of settings for the beamline elements as applied in past beam setups. Typically, each entry has been compiled by receiving input data from various sources such as a recipe generator, a beam setup report, and an ion implant report. A tuner 202 correlates the beamline element settings with beam properties. In particular, the tuner 202 provides the capability to determine the effect that a change to one or more of the initial beamline element settings will have on beam current as well as on any other desired beam properties. As a result, the tuner 202 is configured to predict, calculate or determine and generate tuned beamline element settings from the initial beamline settings that match the desired beam current and any other beam properties. In one embodiment, the tuner 202 is a statistical model. The beamline element settings controller 200 sets the ion source 102 and beamline elements in accordance with the tuned beamline element settings calculated by the tuner 202. A beam monitor 204 receives signals indicative of the beam current from measurements taken by the setup cup 130. Although not shown, the beam monitor 204 is configured to receive signals indicative of other beam properties from measurements taken by sensors located about the various beamline elements. An illustrative but non-exhaustive listing of sensors could include power system readbacks (i.e., voltage and current), magnetic and electrostatic field monitors, optical sensors, beam angle distribution monitor, plasma potential monitor, beamline health monitor (e.g., quartz crystal microbalance), resistivity sensor, thermocouple, etc. A dose repeatability controller 206 examines the beam current measurements and predicts dose repeatability from these measurements. In one embodiment, the predicted dose repeatability (PDR) is determined from the following: PDR = ( Sigma + Tvalue * SigmaRn ) ( TotalPasses * NumberScanLines - 1 ) ( 1 ) wherein, Sigma is the relative standard deviation,Tvalue is the statistical factor relating sample size, N, and confidence level, andSigmaRn is the standard error N measures of current defined as: SigmaRn = Sigma N ( 2 ) The dose repeatability controller 206 compares the predicted dose repeatability to a target value that has been determined to be suitable for obtaining the desired implantation. If the dose repeatability controller 206 determines that the predicted dose repeatability is not suitable for obtaining the ion implantation, then the dose repeatability controller 206 notifies the tuner 202 so that the ion source can be tuned again. In one embodiment, if the dose repeatability controller 206 determines that the predicted dose repeatability is greater than the target value, the tuner 202 tunes the ion source 102 into the setup cup 130 to obtain lower beam noise and/or beam current. Once the ion source 102 has been tuned accordingly, the source directs the ion beam into the setup cup 130 and another determination of the predicted dose repeatability is made. Once the dose repeatability controller 206 determines that the predicted dose repeatability is suitable for obtaining the desired implant (e.g., predicted dose repeatability is less than the target value), then another determination of the predicted dose repeatability is made; but this time it is ascertained from the end station. In order to obtain beam current measurements from the end station, the setup cup 130 is not engaged (except for the one located in the vacuum chamber) so that the ion beam passes into the end station. The profiling Faraday cup 134 moves in and out of the substrate plane within the vacuum chamber 118 without a substrate in the plane. The ion beam 103 passes through the profiling Faraday cup 134 and/or the setup cup 130 located in back of the substrate in the vacuum chamber 118, which then supplies the electrical current to the electronic dose processor 132, which integrates the current with respect to time to determine the cumulative ion dose. As shown in FIG. 2, the controller 104 includes an end station monitor 208 which monitors the beam current measurements from the end station. The dose repeatability controller 206 examines the beam current measurements monitored by the end station monitor 208 and predicts dose repeatability from these measurements in the same manner described above. In addition, the dose repeatability controller 206 compares the predicted dose repeatability to a target value. If the dose repeatability controller 206 determines that the predicted dose repeatability is not suitable for obtaining the ion implantation, then the dose repeatability controller 206 notifies the tuner 202 so that the ion source can be tuned again. In one embodiment, if the dose repeatability controller 206 determines that the predicted dose repeatability is greater than the target value, the tuner 202 tunes the ion source 102 into the end station to obtain lower beam noise and/or beam current. Once the ion source 102 has been tuned accordingly, the source directs the ion beam into the end station and another determination of the predicted dose repeatability is made. Once the dose repeatability controller 206 determines that the predicted dose repeatability is suitable for obtaining the desired implant (e.g., predicted dose repeatability is less than the target value), then the ion implanter 100 is ready for ion implantation of substrates. FIG. 2 only shows the components of the controller 104 that facilitate a general understanding of the approach used to predict the dose repeatability and control the ion implantation according to the predicted dose repeatability. Those skilled in the art will recognize that the controller 104 can have additional components not shown in FIG. 1. For example, the controller 104 may have a user interface component that enables an operator to input commands, data and/or to monitor the ion implanter 100 via the controller 104. In this disclosure, the controller 104 can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. In a preferred embodiment, the processing functions performed by the controller 104 are implemented in software, which includes but is not limited to firmware, resident software, microcode, etc. Furthermore, the processing functions performed by the controller 104 can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the computer, instruction execution system, apparatus, or device. The computer readable medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include a compact disk—read only memory (CD-ROM), a compact disk—read/write (CD-R/W) and a digital video disc (DVD). FIG. 3 shows a graphical representation 300 illustrating the relationship between expected dose repeatability and beam noise that occurs in an ion implantation. In particular, FIG. 3 shows that the expected or predicted dose repeatability for an ion implantation of a substrate improves as the number of passes (i.e., the number of times that a substrate is cycled vertically) through the ion beam. Note that the closer the predicted dose repeatability is to zero, the better the ion implantation will be. FIG. 3 shows that as the number of passes that the substrate is cycled through increases, the beam noise moves from high noise to low noise eventually becoming less than the target dose repeatability which is shown in FIG. 3 as a dashed line. Once the predicted dose repeatability becomes less than the target dose repeatability, then as mentioned above, this is an indication that the ion implanter 100 will produce an implantation that is in conformance with desired parameters. FIG. 4 shows a flow chart describing the process 400 for predicting the dose repeatability for an ion implantation performed for the ion implanter 100 of FIG. 1 according to one embodiment of this disclosure. As shown in FIG. 4, the process 400 begins at 402 where the tuner 202 tunes the ion source 102 in the setup cup 130 to generate an ion beam that has the desired beam current necessary to achieve the ion implantation. The beamline monitor 204 obtains the beam current measurements and supplies them to the dose repeatability controller 206 which predicts dose repeatability at 404. In particular, the dose repeatability controller 206 uses equations 1 and 2 described above to ascertain the predicted dose repeatability from the ion beam measurements. If the dose repeatability controller determines that the predicted dose repeatability is greater than a target dose repeatability for the ion implantation, then tuner 202 retunes the ion source 102 at 406. In particular, the tuner 202 tunes the ion source 102 into the setup cup 130 to obtain lower beam noise and or beam current. Once the ion source 102 has been tuned accordingly, the source directs the ion beam into the setup cup 130 and another determination of the predicted dose repeatability is made at 404. The tuning of the ion source 102 continues until it has been determined that the predicted dose repeatability is less than the target value desired for the ion implantation. Once the dose repeatability controller 206 determines that the predicted dose repeatability is less than the target value, then the ion beam is passed onto the end station. The end station monitor 208 receives current measurements from the profiling faraday cup 134 and/or setup cup 130 located in the vacuum chamber behind the substrate at 408. The end station supplies the beam current measurements from the end station to the dose repeatability controller 206 which predicts dose repeatability from these measurements in the same manner described above at 410. If the dose repeatability controller 206 determines that the predicted dose repeatability is greater than a target dose repeatability for the ion implantation, then tuner 202 retunes the ion source 102 at 412. In particular, the tuner 202 tunes the ion source 102 into the end station to obtain lower beam noise and/or beam current. Once the ion source 102 has been tuned accordingly, the source directs the ion beam into the end station and another determination of the predicted dose repeatability is made at 410. The tuning of the ion source 102 continues until it has been determined that the predicted dose repeatability is less than the target value desired for the ion implantation. Once the dose repeatability controller 206 determines at 410 that the predicted dose repeatability is suitable for obtaining the desired implant (e.g., predicted dose repeatability is less than the target value), then the ion implanter 100 is ready for ion implantation of substrates. In particular, the ion implanter 100 begins the ion implantation of a substrate 116 at 414. Once the substrate has been implanted a determination is made at 416 to ascertain whether there are more substrates to implant. If there are more substrates to implant, then process acts 408-416 are reiterated until it is determined at 416 that there are no more substrates to implant. The foregoing flow chart shows some of the processing functions associated with predicting dose repeatability. In this regard, each block represents a process act associated with performing these functions. It should also be noted that in some alternative implementations, the acts noted in the blocks may occur out of the order noted in the figure or, for example, may in fact be executed substantially concurrently or in the reverse order, depending upon the act involved. Also, one of ordinary skill in the art will recognize that additional blocks that describe the processing functions may be added. For example, additional blocks could be added to show that the predicted dose repeatability value could be used in to provide further control of the ion implantation. In particular, another type of Faraday cup such as a closed loop Faraday cup can be used to obtain beam current measurements while implanting substrates. The dose repeatability controller 206 could then predict the dose repeatability for the implantation of the substrate and compare it to the target dose repeatability. If the predicted dose repeatability is greater than the target dose repeatability, then the controller could have the ion source 102 and the beamline elements tuned during the implantation to ensure that the desired implantation of the substrate is attained. It is apparent that there has been provided with this disclosure an approach that predicts dose repeatability in an ion implantation. While the disclosure has been particularly shown and described in conjunction with a preferred embodiment thereof, it will be appreciated that variations and modifications will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
	abstract	Structures operable to detect radiation are described. The structure may two screens with a phosphor layer, respective. The structure may further include a photosensor array disposed between the first screen and the second screen such that the photosensor array directly contacts the first screen or is directly attached to the first screen using an optical adhesive and directly contacts the second screen or is directly attached to the second screen using an optical adhesive.
	summary
	summary
054328349	claims	1. A whole body x-ray bone densitometry system comprising: a table extending parallel to a Y-axis of an XYZ coordinate system for supporting a patient at a patient position; an x-ray source for emitting a narrow angle fan beam of x-rays to irradiate at any one time a scan line which is transverse to the Y-axis and is substantially shorter than the width of a body cross-section of a typical adult patient occupying the patient position; an x-ray detector aligned with said source along a source-detector axis which is transverse to the Y-axis, for receiving x-rays from the source within the angle of said fan beam after passage thereof through the patient position, said detector comprising a number of detecting elements arranged along a direction transverse to the Y-axis and to the source-detector axis; a source-detector support on which the source and detector are mounted at opposite sides of the patient position; and a scanning mechanism moving at least one of the patient table and the source-detector support relative to the other to scan the patient position with said narrow angle fan beam in successive scans parallel to the Y-axis in which the source-detector axis is at different angles relative to the patient position as between different ones of said successive scans but in each of said successive scans an origin of the fan beam in the source is at the same vertical distance from the patient table. X.sub.1 and X.sub.2 are the positions of an origin of the fan shaped beam along the X-axis before and after the table motion, Z.sub.1 and Z.sub.2 are the positions of the origin along the Z-axis before and after the table motion, .theta. is the negative of the angle through which the source-detector axis pivots between the at least two successive scans, .phi. is the angle that the origin makes with the rotation axis at the end of the rotating motion of the source-detector support, and R is the distance between the origin and the rotation axis. a table for supporting a patient at a patient position, said table having a length and a left side and a right side which are spaced from each other in a direction transverse to the length of the table, said table being selectively movable at least left-right and up-down; an x-ray source for emitting a fan beam of x-rays; an x-ray detector receiving x-rays from the source within an angle subtended by said fan beam after passage thereof through the patient position, said detector comprising a number of detecting elements aligned with respective angular positions in the fan beam and arranged along a direction transverse to the length of said table; a source-detector support supporting the source and detector at opposite sides of the patient position; and a scanning mechanism selectively moving the source-detector support along the length of the table and selectively rotating the source-detector support around the table and selectively moving the table both left-right and up-down to scan the patient position with said fan beam in successive scans along the length of the table in which the source-detector support is at different angles relative to the table as between different ones of said successive scans but the up-down distance between an origin of the fan beam in the source and the table is the same for each of said successive scans. placing a patient on a table; irradiating the patient with a fan beam of x-rays subtending an angle that includes substantially less than the body width of the patient; receiving x-rays from the source within the angle subtended by the fan beam after passage thereof through the patient at a number of radiation detecting positions aligned with angular positions within said angle; scanning the fan beam and the detector along the length of the patient in successive scans and selectively moving at least one of the table and the fan beam along each of two orthogonal axis transverse to the length of the patient between said successive scans to scan the patient from different angles while maintaining a selected vertical distance between an origin of the fan beam and the table. supporting a patient with the length thereof being along the Y-axis of an X,Y,Z orthogonal set of axes; emitting a fan beam of x-rays from an origin to irradiate at any one time less than the entire width of the patient; receiving x-rays from the source within an angle subtended by the fan beam after passage thereof through the patient at a number of individual detecting positions arranged along a plane normal to the Y-axis; moving the fan beam and the detector concomitantly to scan the patient in successive scans which are along the Y-axis but in which the fan beam is at different angles to the patient, rotating the fan beam about a rotation axis parallel to the Y-axis between said successive scans, and moving the table along the X-axis and the Z-axis to maintain a selected vertical distance between the origin and the table to obtain detector outputs for an anterior-posterior view of the entire width of the patient while maintaining the patient's position relative to the table. supporting a patient on a table at a patient position, with the length of the patient being parallel to the Y-axis of an orthogonal X, Y, Z coordinate system and with the width of the patient being parallel to the X-axis; emitting a fan beam of x-rays from an origin in a source at one side of the patient position to irradiate at any one time a scan line which is perpendicular to the Y-axis and has a length at the patient position which is less than the width of a body cross-section of a typical adult patient who is at the patient position; receiving x-rays from the source, within the angle of said fan beam, after passage of the x-rays through the patient position, at an x-ray detector which comprises a number of x-ray detecting elements which are arranged in at least one row transverse to the Y-axis and are at an opposite side of the patient position from the source; supporting the source and detector on a source-detector support for movement as a unit relative to the patient position; and moving at least one of the patient table and the source-detector support relative to the other parallel to the Y-axis to scan the patient position with said fan beam in successive scans, said fan beam being at an angle relative to the patient position during at least one of said scans which is different than the angle during at least another one of said scans; and wherein the vertical distance between the origin of the fan beam and the patient table is the same as between said successive scans. 2. A system as in claim 1 in which said scanning mechanism comprises a table moving mechanism selectively moving the table parallel to the X-axis between said successive scans. 3. A system as in claim 2 in which said table moving mechanism comprises a mechanism selectively moving the table parallel to the Z-axis between said successive scans. 4. A system as in claim 3 in which said scanning mechanism comprises a rotating mechanism selectively rotating the source-detector support about a rotation axis parallel to the Y-axis between said successive scans. 5. A system as in claim 4 in which said scanning mechanism comprises a mechanism moving the table between at least two of said successive scans through a motion having a component parallel to the X-axis over a distance DX and a component parallel to the Z-axis over a distance DZ, where the distances DX and DZ are according to the expressions: EQU DX=(X.sub.2 -X.sub.1)=R[cos .phi.(cos .theta.-1)+sin .phi. sin .theta.] EQU DZ=(Z.sub.2 -Z.sub.1)=R[sin .phi.(cos .theta.-1)-cos .phi. sin .theta.] 6. A system as in claim 5 in which said angle .theta. is about -21.5 degrees, with the negative angle denoting a clockwise rotation of the support about the rotation axis. 7. A system as in claim 6 in which the angle subsumed by said fan beam is about 22 degrees, and the fan beam positions between two of said successive scans overlap by about 0.5 degrees. 8. A system comprising: 9. A system as in claim 8 in which the scanning mechanism comprises a table moving mechanism which between said successive scans moves the table left-right and up-down and rotates the source detector support about a rotation axis that does not pass through the origin of the fan beam. 10. A system as in claim 9 in which said fan beam at said patient position is narrower than the width of a typical adult patient who is in the supine position on the table. 11. A system as in claim 10 in which said beam irradiates overlapping portions of said patient position in said successive scans. 12. A system as in claim 8 in which said scanning mechanism comprises a mechanism carrying out said successive scans for an anterior-posterior view of the patient position and selectively changing the up-down distance between said origin and the table and scanning the beam relative to the patient position for a lateral view without moving the patient relative to the table. 13. A system as in claim 12 in which said scanning mechanism additionally comprises a mechanism for changing the up-down distance between the origin and the table and scanning the patient with the fan beam for a hip view without moving the patient relative to the table. 14. A system as in claim 8 in which said scanning mechanism comprises a mechanism carrying out said successive scans for an anterior-posterior view and selectively changing the up-down distance between said origin and the table and scanning the beam relative to the patient position for a lateral view and a hip view without moving the patient relative to the table. 15. A method comprising: 16. A method as in claim 15 in which the fan beam in said successive scans irradiates overlapping portions of the patient to generate detector measurements for an anterior-posterior view of the patient, and additionally comprising the step of changing the vertical distance between the origin and the table and scanning the beam relative to the patient to obtain a lateral view without moving the patient relative to the table. 17. A method as in claim 16 further comprising changing the vertical distance between the origin and the table and scanning the beam relative to the patient to obtain a hip view without moving the patient relative to the table. 18. A method as in claim 15 further comprising changing the vertical distance between the origin and the table and scanning the beam relative to the patient to obtain a hip view without moving the patient relative to the table. 19. A method comprising: 20. A method as in claim 19 further comprising selectively changing the vertical distance between the origin and the table and the angle of the beam to the patient and scanning the beam relative to the patient to obtain detector outputs for a lateral view without moving the patient relative to the table. 21. A method as in claim 20 further comprising selectively changing the vertical distance between the origin and the table and the angle of the beam to the patient and scanning the beam relative to the patient to obtain detector outputs for a hip view without moving the patient relative to the table. 22. A method as in claim 19 further comprising selectively changing the vertical distance between the origin and the table and the angle of the beam to the patient and scanning the beam relative to the patient to obtain detector outputs for a lateral view and a hip view without moving the patient relative to the table. 23. A method as in claim 19 further comprising processing detector outputs to form and display x-ray images of the patient. 24. A whole body x-ray bone densitometry method comprising: 25. A method as in claim 24 in which said moving step comprises selectively moving the table parallel to the X-axis between said successive scans. 26. A method as in claim 25 in which said moving step comprises selectively moving the table parallel to the Z-axis between said successive scans. 27. A method as in claim 26 in which said moving step comprises selectively rotating the source-detector support between said successive scans about a rotation axis parallel to the Y-axis. 28. A method as in claim 24 in which said moving step comprises selectively moving the table parallel to each of the X-axis and the Z-axis between said successive scans and selectively rotating the source-detector support between said successive scans about a rotation axis parallel to the Y-axis and preventing movement of the source-detector support parallel to the X-axis. 29. A method as in claim 24 in which said moving step comprises causing the vertical from the origin of the fan beam to intersect the table at the same line parallel to the Y-axis during each of said successive scans. 30. A system as in claim 1 in which said scanning mechanism comprises a mechanism maintaining the vertical from the origin of the fan beam in a YZ plane which intercepts the table at the same place during each of said successive scans. 31. A method as in claim 15 in which said scanning step maintains the vertical from the origin of the fan beam in a YZ plane which intercepts the table at the same place during each of said successive scans. 32. A method as in claim 19 in which said moving step maintains the vertical from the origin of the fan beam in a YZ plane which intercepts the table at the same place during each of said successive scans.
054886422	abstract	A system for cooling water from a spent fuel pool of a nuclear power generating plant. The system includes a heat exchanger in which a flow of air is employed to cool a flow of pool water. The performance of the heat exchanger is enhanced by spraying water as a fine mist into the flow of coolant air. The water droplets, preferably less than 100 microns in diameter, coat the heat exchange surface on the air side of the heat exchanger and provide evaporative cooling. The preferred form of heat exchange surface has strip fins.
	description	The disclosed concept pertains generally to nuclear reactor systems. The disclosed concept also pertains to transmitter devices for nuclear reactor systems. The disclosed concept further pertains to methods of measuring environmental conditions with a transmitter device. In many state-of-the-art nuclear reactor systems in-core sensors are employed for measuring the radioactivity within the core at a number of axial elevations. These sensors are used to measure the radial and axial distribution of the power inside the reactor core. This power distribution measurement information is used to determine whether the reactor is operating within nuclear power distribution limits. The typical in-core sensor used to perform this function is a self-powered detector that produces an electric current that is proportional to the amount of fission occurring around it. This type of sensor does not require an outside source of electrical power to produce the current and is commonly referred to as a self-powered detector and is more fully described in U.S. Pat. No. 5,745,538, issued Apr. 28, 1998, and assigned to the Assignee of this invention. FIG. 1 provides a diagram of the mechanisms that produce the current I(t) in a self-powered detector element 10. A neutron sensitive material such a vanadium is employed for the emitter element 12 and emits electrons in response to neutron irradiation. Typically, the self-powered detectors are grouped within instrumentation thimble assemblies. A representative in-core instrumentation thimble assembly 16 is shown in FIG. 2. The signal level generated by the essentially non-depleting neutron sensitive emitter 12 shown in FIG. 1 is low, however, a single, full core length neutron sensitive emitter element provides an adequate signal without complex and expensive signal processors. The proportions of the full length signal generated by the single neutron sensitive emitter element attributable to various axial regions of the core are determined from apportioning the signal generated by different lengths of gamma sensitive elements 14 which define the axial regions of the core and are shown in FIG. 2. The apportioning signals are ratioed which eliminates much of the effects of the delayed gamma radiation due to fission products. The in-core instrumentation thimble assemblies also include a thermocouple 18 for measuring the temperature of the coolant exiting the fuel assemblies. The electrical signal output from the self-powered detector elements and the thermocouple in each in-core instrumentation thimble assembly in the reactor core are collected at the electrical connector 20 and sent to a location well away from the reactor for final processing and use in producing the measured core power distribution. FIG. 3 shows an example of a core monitoring system presently offered for sale by Westinghouse Electric Company LLC, Cranberry, Pa., with a product name WINCISE™ that employs fixed in-core instrumentation thimble assemblies 16 within the instrument thimbles of the fuel assemblies within the core to measure the core's power distribution. Cabling 22 extends from the instrument thimble assemblies 16 through the containment seal table 24 to a single processing cabinet 26 where the outputs are conditioned, digitized and multiplexed and transmitted through the containment walls 28 to a computer workstation 30 where they can be further processed and displayed. The thermocouple signals from the in-core instrumentation thimble assemblies are also sent to a reference junction unit 32 which transmits the signals to an inadequate core cooling monitor 34 which communicates with the plant computer 36 which is also connected to the workstation 30. Because of the hostile environment within the containment walls 28, the signal processing cabinet 26 has to be located a significant distance away from the core and the signal has to be sent from the detectors 16 to the signal processing cabinet 26 through specially constructed cables that are extremely expensive and the long runs reduce the signal to noise ratio. Unfortunately, these long runs of cable have proved necessary because the electronics for signal processing has to be shielded from the highly radioactive environment surrounding the core region. In previous nuclear plant designs, the in-core detectors entered the reactor vessel from the lower hemispherical end and entered the fuel assemblies' instrument thimble from the bottom fuel assembly nozzle. In at least some of the current generation of nuclear plant designs, such as the AP1000 nuclear plant, the in-core monitoring access is located at the top of the reactor vessel, which means that during refueling all in-core monitoring cabling will need to be removed before accessing the fuel. A wireless in-core monitor that is self-contained within the fuel assemblies and wirelessly transmits the monitored signals to a signal receiver positioned inside the reactor vessel but away from the fuel would allow immediate access to the fuel without the time-consuming and expensive process of disconnecting, withdrawing and storing the in-core monitoring cables before the fuel assemblies could be accessed, and restoring those connections after the refueling process is complete. A wireless alternative would thus save days in the critical path of a refueling outage. A wireless system also allows every fuel assembly to be monitored, which significantly increases the amount of core power distribution information that is available. However, a wireless system requires that electronic components be located at or near the reactor core where gamma and neutron radiation and high temperatures would render semi-conductor electronics inoperable within a very short time. Vacuum tubes are known to be radiation insensitive, but their size and electric current demands have made their use impractical until recently. Recent developments in micro-electromechanical devices have allowed vacuum tubes to shrink to integrated circuit component sizes and significantly reduce power draw demands. Such a system is described in U.S. patent application Ser. No. 12/986,242, entitled “Wireless In-core Neutron Monitor,” filed Jan. 7, 2011. The primary electrical power source for the signal transmitting electrical hardware for the embodiment disclosed in the afore-noted patent application is a rechargeable battery shown as part of an exemplary power supply. The charge on the battery is maintained by the use of the electrical power produced by a dedicated power supply self-powered detector element that is contained within the power supply, so that the nuclear radiation in the reactor is the ultimate power source for the device and will continue so long as the dedicated power supply self-powered detector element is exposed to an intensity of radiation experienced within the core. Accordingly, one object of this disclosed concept is to provide a mechanism to transmit data of environmental conditions within an instrument thimble of a fuel assembly to a remote location. These needs and others are met by the disclosed concept, which are directed to an improved nuclear reactor system, transmitter device therefor, and associated method of measuring a number of environmental conditions. As one aspect of the disclosed concept, a transmitter device includes a neutron detector structured to detect neutron flux, a capacitor electrically connected in parallel with the neutron detector, a gas discharge tube having an input end and an output end, and an antenna electrically connected to the output end. The input end is electrically connected with the capacitor. The antenna is structured to emit a signal corresponding to the neutron flux. As another aspect of the disclosed concept, a nuclear reactor system including a fuel assembly having an instrument thimble, and the aforementioned transmitter device is provided. As another aspect of the disclosed concept, a method of measuring a number of environmental conditions with the aforementioned transmitter device is provided. The method includes the steps of detecting neutron flux with the neutron detector; storing energy in the capacitor until a breakdown voltage of the gas discharge tube is reached; and emitting a signal with the antenna corresponding to the neutron flux. The primary side of nuclear power generating systems which are cooled with water under pressure comprises a closed circuit which is isolated from and in heat exchange relationship with a secondary side for the production of useful energy. The primary side comprises the reactor vessel enclosing a core internal structure that supports a plurality of fuel assemblies containing fissile material, the primary circuit within heat exchange steam generators, the inner volume of a pressurizer, pumps and pipes for circulating pressurized water; the pipes connecting each of the steam generators and pumps to the reactor vessel independently. Each of the parts of the primary side comprising a steam generator, a pump and a system of pipes which are connected to the reactor vessel form a loop of the primary side. For the purpose of illustration, FIG. 4 shows a simplified nuclear reactor system, including a generally cylindrical pressure vessel 40, having a closure head 42 enclosing a nuclear core 44. A liquid reactor coolant, such as water, is pumped into the vessel 40 by pump 46 through the core 44 where heat energy is absorbed and is discharged to a heat exchanger 48, typically referred to as a steam generator, in which heat is transferred to a utilization circuit (not shown), such as a steam driven turbine generator. The reactor coolant is then returned to the pump 46 completing the primary loop. Typically, a plurality of the above-described loops are connected to a single reactor vessel 40 by reactor coolant piping 50. An exemplary reactor design to which this invention can be applied is illustrated in FIG. 5. In addition to the core 44 comprised of a plurality of parallel, vertical, co-extending fuel assemblies 80, for purpose of this description, the other vessel internal structures can be divided into the lower internals 52 and the upper internals 54. In conventional designs, the lower internals' function is to support, align and guide core components and instrumentation as well direct flow within the vessel. The upper internals 54 restrain or provide a secondary restraint for the fuel assemblies 80 (only two of which are shown for simplicity in this figure), and support and guide instrumentation and components, such as control rods 56. In the exemplary reactor shown in FIG. 5, coolant enters the reactor vessel 40 through one or more inlet nozzles 58, flows down through an annulus between the reactor vessel 40 and the core barrel 60, is turned 180° in a lower reactor vessel plenum 61, passes upwardly through a lower support plate and a lower core plate 64 upon which the fuel assemblies 80 are seated, and through and about the assemblies. In some designs, the lower support plate 62 and the lower core plate 64 are replaced by a single structure, the lower core support plate that has the same elevation as 62. Coolant exiting the core 44 flows along the underside of the upper core plate 66 and upwardly and through a plurality of perforations 68 in the upper core plate 66. The coolant then flows upwardly and radially to one or more outlet nozzles 70. The upper internals 54 can be supported from the vessel or the vessel head 42 and includes an upper support assembly 72. Loads are transmitted between the upper support assembly 72 and the upper core plate 66 primarily by a plurality of support columns 74. Each support column is aligned above a selected fuel assembly 80 and perforations 68 in the upper core plate 66. The rectilinearly movable control rods 56 typically include a drive shaft 76 and a spider assembly 78 of neutron poison rods that are guided through the upper internals 54 and into aligned fuel assemblies 80 by control rod guide tubes 79. FIG. 6 is an elevational view represented in vertically shortened form, of a fuel assembly being generally designated by reference character 80. The fuel assembly 80 is the type used in a pressurized water reactor, such as the reactor of FIG. 5, and has a structural skeleton which at its lower end includes a bottom nozzle 82. The bottom nozzle 82 supports the fuel assembly on the lower core support plate 64 in the core region of the nuclear reactor. In addition to the bottom nozzle 82, the structural skeleton of the fuel assembly 80 also includes a top nozzle 84 at its upper end and a number of guide tubes or thimbles 86 which extend longitudinally between the bottom and top nozzles 82 and 84 and at opposite ends are rigidly attached thereto. The fuel assembly 80 further includes a plurality of transverse grids 88 axially spaced along and mounted to the guide thimbles 86 (also referred to as guide tubes) and an organized array of elongated fuel rods 90 transversely spaced and supported by the grids 88. Although it cannot be seen in FIG. 6, the grids 88 are conventionally formed from orthogonal straps that are interleaved in an egg-crate pattern with the adjacent interface of four straps defining approximately square support cells through which the fuel rods 90 are supported in transversely spaced relationship with each other. In many conventional designs, springs and dimples are stamped into the opposing walls of the straps that form the support cells. The springs and dimples extend radially into the support cells and capture the fuel rods therebetween; inserting pressure on the fuel rod cladding to hold the rods in position. Also, the assembly 80 has an instrumentation tube 92 located in the center thereof that extends between and is mounted to the bottom and top nozzles 82 and 84. With such an arrangement of parts, the fuel assembly 80 forms an integral unit capable of being conveniently handled without damaging the assembly of parts. As mentioned above, the fuel rods 90 in the array thereof in the assembly 80 are held in spaced relationship with one another by the grids 88 spaced along the fuel assembly length. Each fuel rod 90 includes a plurality of nuclear fuel pellets 94 and is closed at its opposite ends by upper and lower end plugs 96 and 98. The fuel pellets 94 are maintained in a stack by a plenum spring 100 disposed between the upper end plug 96 in the top of the pellet stack. The fuel pellets 94, composed of fissile material, are responsible for creating the reactive power of the reactor. The cladding, which surrounds the pellets, functions as a barrier to prevent fission byproducts from entering the coolant and further contaminating the reactor system. To control the fission process, a number of control rods 56 are reciprocally movable in the guide thimbles 86 located at predetermined positions in the fuel assembly 80. Specifically, a rod cluster control mechanism (also referred to as a spider assembly) 78 positioned above the top nozzle 84 supports the control rods 56. The rod cluster control mechanism has an internally threaded cylindrical hub member 102 with a plurality of radially extending flukes or arms 104 that with the control rods 56 form the spider assembly 78 that was previously mentioned with respect to FIG. 5. Each arm 104 is interconnected to the control rods 56 such that the control mechanism 78 is operable to move the control rods vertically in the guide thimbles to thereby control the fission process in the fuel assembly 80, under the motor power of control rod drive shafts 76 (shown in FIG. 5) which are coupled to the control rod hubs 102, all in a well known manner. FIG. 7 shows a schematic circuitry diagram of a transmitter device 200, in accordance with one non-limiting embodiment of the disclosed concept. The example transmitter device 200 is preferably located within one of the instrument thimbles 86 of the fuel assembly of FIG. 6. As will be discussed in greater detail hereinbelow, the transmitter device 200 allows an environmental condition (e.g., without limitation, neutron flux) within the instrument thimble 86 (FIG. 6) to be monitored wirelessly. The example transmitter device 200 includes a self-powered neutron detector 210, a first capacitor 212 electrically connected in parallel with the neutron detector 210, a gas discharge tube 214, an antenna 220, and an oscillator circuit 222. One example of a suitable gas discharge tube that may be employed in the disclosed concept is presently offered for sale by Littlefuse, Inc., of Chicago, Ill., and has a product name Gas Discharge Tube. The gas discharge tube 214 has an input end 216 and an output end 218. In one example embodiment, the gas discharge tube 214 is designed as a spark gap device wherein an arc, or spark, occurs when the input end 216 is electrically connected with the output end 218. In another example embodiment, the gas discharge tube 214 is designed to operate with a relatively less intense glow discharge occurring when the input end 216 electrically connects with the output end 218. The input end 216 is electrically connected with the first capacitor 212, and the output end 218 is electrically connected with the antenna 220. As shown, the oscillator circuit 222 includes a second capacitor 224 and an inductor 226 electrically connected in parallel with the second capacitor 224. The second capacitor 224 and the inductor 226 are each electrically connected with the output end 218 and the antenna 220. In operation, when the transmitter device 200 is located within one of the instrument thimbles 86 (FIG. 6), the neutron detector 210 absorbs neutrons, causing electrons to migrate outwardly and thus create a current. Accordingly, the neutron detector 210, and thus the transmitter device 200, is advantageously self-powered (i.e., devoid of a separate powering mechanism). As the neutron detector 210 generates a current, it charges the first capacitor 212. FIG. 8 shows a graph of voltage V1 versus time measured at the first capacitor 212. As shown, the voltage V1 increases until a voltage Vb is reached. The voltage Vb is the breakdown voltage of the gas discharge tube 214. Once the breakdown voltage Vb is reached, the gas discharge tube 214 becomes conductive such that the input end 216 and the output end 218 electrically connect the first capacitor 212 to the antenna 220 and the oscillator circuit 222. The oscillator circuit 222 is an inherently unstable circuit. As such, when the breakdown voltage Vb is reached, an intense oscillation is triggered in the oscillator circuit 222 for a short period of time. FIG. 9 shows a graph of voltage V2 versus time measured in the oscillator circuit 222. As shown, the voltage V2 generally begins at zero volts, oscillates for a relatively short period of time, and thereafter returns to zero volts before repeating the cycle. The dampening of the oscillations is due to energy being dissipated by electromagnetic emissions from the antenna 220 and resistive losses. Accordingly, the oscillator circuit 222 pulses the antenna 220, which emits a wireless signal. It will be appreciated that the period between the pulsed signals emitted by the antenna 220 corresponds inversely to the neutron flux detected by the neutron detector 210. More specifically, the current generated by the neutron detector 210 is directly proportional to the neutron flux within the instrument thimble 86 (FIG. 6), and the breakdown voltage Vb is relatively constant. As such, the period between pulses (see, for example, t1 in FIG. 9) is also inversely proportional to the neutron flux within the instrument thimble 86 (FIG. 6). Therefore, a suitable wireless receiver receiving the signal emitted by the antenna 220 can readily be calibrated to determine the neutron flux within the instrument thimble 86 (FIG. 6). Additionally, the energy of the pulsed transmissions of the antenna 220 remains essentially the same even if the reactor core power is very low. The pulses simply occur less often. Furthermore, because the frequency of the transmitter device 200 is independent of pulse operation, a device designer is able to select the frequency of the transmitter device 200. This advantageously facilitates the use of many different transmitter devices at different locations in the fuel assembly 80, and in other fuel assemblies in the core. An operator would be able to identify each individual transmitter device by its associated frequency, which is dependent on the values of the capacitance of the second capacitor 224 and the inductance of the inductor 226. Accordingly, environmental conditions such as neutron flux are advantageously able to be monitored wirelessly at many different locations within the fuel assembly 80. FIG. 10 shows a schematic circuitry diagram of another transmitter device 300, in accordance with another non-limiting embodiment of the disclosed concept. As shown, the transmitter device 300 is structured similar to the transmitter device 200 (FIG. 7), and like components are labeled with like reference numbers. For ease of illustration and economy of disclosure, only the antenna 320 and the oscillator circuit 322 are indicated with reference numbers. However, as shown, the oscillator circuit 322 of the transmitter device 300 further includes a resistance temperature detector 328 electrically connected in series with the inductor 326 and electrically connected to the second capacitor 324. The resistance temperature detector 328 increases its electrical resistance as the temperature of the environment in which it is located increases. In accordance with one aspect of the disclosed concept, the resistance temperature detector 328 alters the signal emitted by the antenna 320 in a detectable way. More specifically, the amplitude decay rate of the voltage of the oscillator circuit 322 will be altered with the inclusion of the resistance temperature detector 322. Accordingly, the change in the amplitude decay rate measured by a suitable wireless receiver will allow an operator to readily determine a given temperature at a location within the instrument thimble 86 (FIG. 6). It follows that the transmitter device 300 is advantageously able to provide an indication to an operator of neutron flux (i.e., in the same manner as the transmitter device 200 shown in FIG. 7) and also temperature within the instrument thimble 86 (FIG. 6). FIGS. 11 and 12 show schematic circuitry diagrams of two other transmitter devices 400,500, respectively, in accordance with other non-limiting embodiments of the disclosed concept. As shown, the transmitter devices 400,500 are structured similar to the transmitter devices 200,300 (FIGS. 7 and 10), and like components are labeled with like reference numbers. For ease of illustration and economy of disclosure, only the antennas 420 and the oscillator circuits 422,522 are identified with reference numbers. As shown in FIG. 11, the oscillator circuit 422 further includes a second inductor (e.g., without limitation, variable inductor 430) electrically connected in series with the first inductor 426 and the resistance temperature detector 428. Furthermore, the variable inductor 430 is electrically connected to with the second capacitor 424. As shown in FIG. 12, the oscillator circuit 522 further includes a variable capacitor 532 electrically connected in parallel with the second capacitor 524. The variable capacitor 532 is also electrically connected to the inductor 526 and the resistance temperature detector 528. Advantageously, environmentally induced changes in the electrical values of either the variable inductor 430 or the variable capacitor 532 will produce a detectable shift in the pulse transmission frequency. It will be appreciated that the transmitter devices 400,500 are advantageously able to provide an indication to an operator of up to three environmental conditions within the instrument thimble 86 (FIG. 6). For example, the transmitter devices 400,500 each, via the emitted signals of the respective antennas 420,520, are each able to communicate to a wireless receiver data corresponding to the neutron flux and the temperature within the instrument thimble 86 (FIG. 6) in the same manner as the transmitter device 300, discussed above. Additionally, the variable inductor 430 (FIG. 11) and the variable capacitor 532 (FIG. 12) are each structured to alter the frequency of the emitted signal of the respective antennas 420,520 in a detectable way. The altered frequency provides a mechanism by which a third environmental condition (e.g., without limitation, pressure, total neutron dose of a fuel rod over time, water flow rate) can be measured by the transmitter devices 400,500 and reported wirelessly to a suitable receiver. For example, the pressure within a fuel rod may create a deformation that causes a movement near a coil of the variable inductor 430 to cause a detectable frequency shift in the emitted signal of the antenna 420, thus allowing the pressure to be monitored wirelessly. FIG. 13 shows a schematic circuitry diagram of another transmitter device 600, in accordance with another non-limiting embodiment of the disclosed concept. As shown, the transmitter device 600 is structured similar to the transmitter devices 200,300,400,500 (FIGS. 7 and 10-12), and like components are labeled with like reference numbers. More specifically, the transmitter device 600 includes a neutron detector 610, a capacitor 612, a gas discharge tube 614, an antenna 620, and an oscillator circuit 622 that each perform the same functions as the respective components of the transmitter devices 200,300,400,500 (FIGS. 7 and 10-12). As shown, the transmitter device 600 further includes a number of Marx bank stages (e.g., two Marx bank stages 642,644 are shown) electrically connected between the neutron detector 610 and the gas discharge tube 614. It will be appreciated that any suitable alternative number of Marx bank stages may be employed ahead of a gas discharge tube (i.e., and after a neutron detector) in order to perform the desired function of enhancing circuit performance. The Marx bank stages 642,644 each include a respective capacitor 646,648, a respective first resistor 650,652, a respective second resistor 654,656, and a respective gas discharge tube 658,660. It will be appreciated that a method of measuring a number of environmental conditions with a transmitter device 200,300,400,500,600 includes the steps of detecting neutron flux with a neutron detector 210,610 storing energy in a capacitor 212,612 until a breakdown voltage Vb of a gas discharge tube 214,614 is reached, and emitting a signal with an antenna 220,320,420,520,620 corresponding to the neutron flux. The method may further include the steps of pulsing the antenna 220,320,420,520,620 with an oscillator circuit 222,322,422,522,622 altering the signal emitted by the antenna 220,320,420,520,620 with a resistance temperature detector 328,428,528, and/or altering the signal emitted by the antenna 220,320,420,520,620 with a variable inductor 430 or a variable capacitor 532. The novel transmitter devices 200,300,400,500,600 are able to measure the disclosed environmental conditions within the instrument thimble 86 (FIG. 6) and withstand the relatively harsh operating conditions for at least two reasons. First, the transmitter devices 200,300,400,500,600 are each advantageously devoid of semiconductors. Second, the transmitter devices 200,300,400,500,600 generally include only one single powering mechanism (e.g., the respective neutron detectors (only the neutron detectors 210,610 are indicated)). Known attempts at providing a wireless mechanism to communicate data on environmental conditions typically require more power than is available from a neutron detector, and/or are not able to withstand the relatively harsh radiation environment due to the inclusion of semiconductors. Additionally, known devices (not shown) exhibit relatively low transmitter power, and as such shutdown completely when the reactor power is decreased below a critical threshold. The transmitter devices 200,300,400,500,600 are novel in their combination of a self-powered neutron detector 210,610 and energy storage capacitor 212,612 to achieve reasonable transmission power over a wide reactor power range. Furthermore, as discussed, the transmitter devices 400,500 are advantageously able to transmit readings on up to three different environmental parameters concurrently from a given sensing location within the instrument thimble 86. Moreover, because all of the monitoring is being done wirelessly, the need for major reactor vessel penetrations and cabling to monitor environmental conditions is reduced and/or eliminated. Accordingly, the disclosed concept provides for an improved (e.g., without limitation, better able to monitor environmental conditions within an instrument thimble 86) nuclear reactor system, transmitter device 200,300,400,500,600 therefor, and associated method of measuring environmental conditions. While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.
	summary
	claims	1. A containment airlock for working on a site on which radiological, asbestos, biological and/or chemical contamination occurs, comprising:a self-supporting frame, the frame being articulated so that it is expandable from a collapsed storage position and an extended work position,a flexible containment shell that is configured to be removably assembled to the frame, wherein the flexible containment shell comprises panels that are each configured to prevent contamination of an interior or an exterior of the containment airlock by radiological, asbestos, biological and/or chemical contamination throughout each panel, andhooks to removably attach the shell to the frame, wherein the hooks suspend the shell inside an internal space defined by the frame when the frame is in the extended work position,wherein the frame comprises a first collapsible plane frame, a second collapsible plane frame, and rigid single-piece reinforcing rods that connect the first collapsible plane frame to the second collapsible plane frame,wherein each of the first collapsible plane frame and the second collapsible plane frame contains vertices of the frame and articulated reinforcing rods that connect the vertices of the first collapsible plane frame to each other and the vertices of the second collapsible plane frame to each other,wherein each of the articulated reinforcing rods comprises a first rigid segment, a second rigid segment and at least one intermediate articulation connecting the first rigid segment to the second rigid segment,wherein the rigid single-piece reinforcing rods connect the vertices of the first collapsible plane frame to the vertices of the second collapsible plane frame, wherein the first collapsible plane frame and the second collapsible plane frame are located at opposite longitudinal ends of the rigid single-piece reinforcing rods,wherein the first collapsible plane frame and the second collapsible plane frame are configured such that the first rigid segment and the second rigid segment of the articulated reinforcing rods move towards the rigid single-piece reinforcing rods when the frame moves from the extended work position to the collapsed storage position,wherein the first collapsible plane frame and the second collapsible plane frame are configured such that the first rigid segment and the second rigid segment of the articulated reinforcing rods move away from the rigid single-piece reinforcing rods when the frame moves from the collapsed storage position to the extended work position,wherein each vertex of the first collapsible plane frame is connected to at least two articulated reinforcing rods so that each side of the first collapsible plane frame collapses when the frame moves from the extended work position to the collapsed storage position,wherein each vertex of the second collapsible plane frame is connected to at least two articulated reinforcing rods so that each side of the second collapsible plane frame collapses when the frame moves from the extended work position to the collapsed storage position,wherein each vertex of the first collapsible plane frame and each vertex of the second collapsible plane frame is configured to guide in rotation the segments of the articulated reinforcing rods relative to the vertex towards the inside of the frame when the frame moves from the extended work position to the collapsed storage position, andwherein each vertex of the first collapsible plane frame and each vertex of the second collapsible plane frame is configured to guide in rotation the segments of the articulated reinforcing rods relative to the vertex towards the outside of the frame when the frame moves from the collapsed storage position to the extended work position. 2. The containment airlock according to claim 1, wherein the intermediate articulation of each articulated reinforcing rod is configured to rotate and to guide the first rigid segment of the reinforcing rod relative to the second rigid segment of the reinforcing rod towards the inside of the frame when the frame moves from the extended work position to the collapsed storage position, andwherein the intermediate articulation of each articulated reinforcing rod is configured to rotate and to guide the first rigid segment of the reinforcing rod relative to the second rigid segment of the reinforcing rod towards the outside of the frame when the frame moves from the collapsed storage position to the extended work position. 3. The containment airlock according to claim 1, wherein the intermediate articulation of each articulated reinforcing rod is located approximately in the middle of the articulated reinforcing rod. 4. The containment airlock according to claim 1, wherein the intermediate articulation of at least one of the articulated reinforcing rods comprises a locking element configured to lock the position of the first rigid segment of the reinforcing rod relative to the position of the second rigid segment of the reinforcing rod. 5. The containment airlock according to claim 4, wherein the intermediate articulation comprises a clevis and wherein the locking element comprises a latch that is free to move relative to the clevis between a locked position and an unlocked position of the articulation. 6. The containment airlock according to claim 1, wherein the intermediate articulation of each articulated reinforcing rod is configured to rotate and to guide the first rigid segment of the reinforcing rod relative to the second rigid segment of the reinforcing rod about a pivot link, andwherein at least one of the vertices is configured to rotate and to guide the first rigid segment of the articulated reinforcing rod relative to the vertex about a pivot link. 7. The containment airlock according to claim 1, wherein at least one of the vertices comprises a housing to partially house the first rigid segment of the articulated reinforcing rod,wherein the housing is at least partially delimited by walls configured to make the first rigid segment pivot relative to the vertex when the frame moves from the extended work position to the collapsed storage position, andwherein the housing is at least partially delimited by walls configured to make the first rigid segment pivot relative to the vertex from the collapsed storage position to the extended work position. 8. The containment airlock according to claim 1, wherein at least one of the vertices comprises an internal end piece configured to engage by cooperation of shapes at least one segment of the articulated reinforcing rod connected to the vertex. 9. The containment airlock according to claim 1, wherein at least one of the vertices comprises at least one first side wall, a second side wall, a horizontal wall and an internal wall,wherein the first side wall, the second side wall and the horizontal wall are orthogonal in pairs and intersecting each other, wherein the internal wall extends perpendicular to the horizontal wall,wherein each of the side walls has an approximately triangular external surface, wherein the internal wall comprises a first segment that extends parallel to the first lateral wall and a second segment that extends parallel to the second lateral wall, each of the first segment and the second segment having an approximately triangular external surface,wherein the internal wall and the first side wall delimit a first internal housing for the first segment or the second segment of the articulated reinforcing rod, wherein the internal wall and the second side wall delimit a second internal housing for the first segment or the second segment of another articulated reinforcing rod, wherein the internal wall and the side walls delimit a central conduit for one of the rigid single-piece reinforcing rods. 10. The containment airlock according to claim 1, wherein the first collapsible plane frame is a horizontal plane support frame, wherein the second collapsible plane frame is a horizontal plane top frame, wherein the rigid single-piece reinforcing rods is the uprights of the frame. 11. The containment airlock according to claim 10, wherein the containment airlock has a generally parallelepiped shape when the frame is in the extended work position. 12. The containment airlock according to claim 11, wherein the containment airlock has a generally parallelepiped shape when the frame is in the collapsed storage position. 13. The containment airlock according to claim 1, wherein the shell is made of a dust tight material. 14. The containment airlock according to claim 1, wherein the shell is made of a single-piece by welded plastic panels. 15. The containment airlock according to claim 1, wherein the shell is made of a plastic material comprising cross-linked polyurethane and/or a vinyl polymer, such as polyvinyl chloride. 16. The containment airlock according to claim 1, comprising depressurisation means configured to create a vacuum inside the airlock, relative to the air pressure outside the airlock. 17. A containment assembly comprising a plurality of containment airlocks according to claim 1 that are adjacent to each other and connected together, to form a containment zone, particular to protect against radiological, asbestos, biological and/or chemical contamination.
040642046	summary	The present invention relates generally to improvements in the manufacture of nuclear fuel materials suitable for use in high temperature gas cooled nuclear reactors. More particularly, the present invention relates to a composition suitable for the manufacture of nuclear fuel compacts at lower fabrication pressures and without the use of externally applied mold release agents. Nuclear fuel compacts in the form of rods are used in high temperature gas cooled nuclear reactors. Such nuclear fuel rods are generally manufactured by surrounding nuclear fuel particles with a matrix which consists of a mixture of graphite flour and pitch. As used herein, the term "pitch" refers to residual products resulting from the destructive distillation of such organic materials as coal, petroleum and wood. The nuclear fuel rods are formed in a metallic mold by either of two methods. In one method, the mold is filled with nuclear fuel particles and a hot graphite-pitch matrix is injected into the mold so as to surround the nuclear fuel particles. In another method, a graphite-pitch matrix is prepared and granulated. The granulated matrix is mixed with nuclear fuel particles to provide a molding mixture containing nuclear fuel particles. The molding mixture of granulated matrix and nuclear fuel particles is then filled into the mold. Thereafter the molding mixture is heated and compressed within the mold. In both methods, after the fuel rod is formed in the mold, the mold is cooled and the fuel rod is ejected from the mold by pushing the fuel rod from the mold. The viscosity of the matrix of graphite flour and pitch at the temperature at which the fuel rod is formed by the above described methods is an important factor in determining the pressure required to provide a suitably dense nuclear fuel compact. It is desirable to reduce the viscosity to permit lower fabrication pressures to be used. Excessive fabrication pressures can result in damage to the nuclear fuel particles during formation of nuclear fuel rod. It would be desirable to provide an additive for nuclear fuel molding mixtures which would act to reduce the fabrication pressure when fuel rods are formed from the molding mixture. After ejection from the mold, the green fuel rod is placed in a graphite fuel element and is heated to between 1200.degree. and 2000.degree. C to carbonize the hydrocarbons. The graphite fuel element usually has a hexagonally shaped cross section and an array of between about 50 to about 210 holes for receiving the fuel rods. An approximately equal number of coolant holes extend through the length of the graphite fuel element. The heat treatment causes the binder material in the fuel rod matrix to undergo simultaneous decomposition and carbonization. A plurality of green fuel rods are placed in each fuel hole. During the carbonizing heat treatment the green fuel rods tend to slump and adhere to the walls of the fuel holes in the graphite fuel element. Such adherence is detrimental to subsequent operation of the fuel element in that differential expansion or contraction of the graphite fuel element and the fuel rods may result in cracking of the fuel rods. It would be desirable to reduce or eliminate the tendency of the fuel rods to adhere to the walls of the fuel holes during the carbonizing heat treatment. Accordingly, it is a principal object of the present invention to provide an improved method for the manufacture of nuclear fuel rods suitable for use in high temperature gas cooled reactors. It is another object of the present invention to provide a matrix formulation suitable for use in the preparation of nuclear fuel rods which has a lower viscosity at fabrication temperatures, thereby permitting fuel rod fabrication at lower temperatures and increased productivity. It is a further object of the present invention to provide a matrix formulation suitable for use in the preparation of nuclear fuel rods which decreases or eliminates the adhesion of fuel rods to graphite fuel elements after heating of the fuel rods in the graphite fuel elements. Generally, in accordance with various features of the present invention, nuclear fuel rods are manufactured, utilizing a graphite flour-pitch matrix formulation having an additive homogeneously dispersed therein. The matrix formulation has a decreased viscosity at fabrication temperatures which permits manufacture of the fuel rods with lower fabrication pressures. Also, the matrix formulation does not cause the fuel rod to adhere or bond to the fuel element during heat treatment of the fuel rod in the fuel element. The nuclear fuel rods are suitable for use in high temperature gas cooled nuclear reactors. In the method of manufacture, a matrix of pitch, and graphite flour is formed. The matrix is preferably formed by heating the pitch to an elevated temperature of from about 100.degree. C to about 300.degree. C and thoroughly mixing the graphite flour with the pitch at the elevated temperature to uniformly blend the graphite flour and pitch. The mixture is thereafter cooled. Upon cooling the mixture is ground to provide a particulate matrix with a particle size suitable for nuclear fuel rod formation. The matrix may also be formed by grinding the pitch to a suitable particle size and blending the graphite flour with the ground pitch to provide the matrix. The additive may be dispersed in the matrix either during or after its preparation, as will be explained more fully hereinafter. In one embodiment of the invention, the matrix is blended with a suitable amount of a particulate nuclear fuel material to form a molding mixture. Thereafter, nuclear fuel rods are formed by placing the molding mixture into a steel mold and compressing the molding mixture in the mold. In another embodiment of the invention, the matrix is heated and injected into a steel mold filled with particulate nuclear fuel material. In both embodiments, after ejection of the fuel rods from the mold, the fuel rods are placed in a graphite fuel element and are heated to a temperature of between about 1200.degree. to 2000.degree. C. In accordance with the present invention, an additive is combined with the matrix of graphite flour and pitch. The additive reduces the viscosity of the matrix at the temperature used in the fabrication of the fuel rods and reduces the tendency of the fuel rods to adhere to the graphite fuel element after being heated in the fuel element. The additive also reduces the shear stress required to release the fuel rods from the metal mold in which the fuel rods are fabricated. In this connection, a shear stress of less than about 50 psig is sufficient to release a fuel rod from the metal mold when the additive of the invention is present at the indicated levels. In general, the additive is selected from saturated and unsaturated alcohols having a carbon chain length of from 12 to 20, saturated and unsaturated fatty acids having a carbon chain length of from 12 to 20, saturated and unsaturated primary amines derived from fatty acids having a carbon chain length of from 12 to 26 and saturated hydrocarbons derived from petroleum having a molecular weight in the range of from about 350 to about 140. The additive is combined with the matrix at a level sufficient to provide from about 0.5 percent to about 30 percent by weight of additive based on the weight of the molding mixture. The nuclear fuel may be any fissionable or breeder nuclear fuel material usually associated with the manufacture of gas cooled nuclear reactor fuel elements. Suitable nuclear fuel materials are diluted or undiluted pyrolytic carbon coated ThC.sub.2, ThO, UO.sub.2, UC.sub.2, (Th,U)O.sub.2, or (Th,U)C.sub.2 mixtures. The nuclear fuel material is preferably substantially spherical in shape and preferably has a particle size in the range of from about 0.3 to about 1.2 mm. The graphite flour may be derived from any carbonaceous material and preferably has a particle size of at least less than about 0.040 mm. Preferably the graphite flour has a particle size in the range of from about 0.0002 to about 0.040 mm. The pitch used in the matrix of the present invention may be any of the residual products resulting from the destructive distillation of coal, petroleum and wood. The pitch has a softening point of less than about 300.degree. F and has a viscosity in the range of from about 100 to about 1000 poises at a temperature of 275.degree. C as measured by an Instron capillary rheometer at a shear rate of 100 sec.sup.-1. More particularly, the additive of the present invention is preferably selected from the group consisting of 1-octadecanol, 1-hexadecanol, oleic acid, stearic acid, 1-octadecylamine, petrolatum, and mixtures thereof. As indicated, the additive is used at a level from about 0.5 to about 30 percent by weight of the matrix of graphite flour and pitch and is preferably used at a level of from about 5 to about 15 percent by weight of the matrix. The additives of the present invention provide a matrix which has a viscosity of less than about 1000 poise as determined by means of a capillary viscometer at a temperature of 175.degree. C and a wall shear rate of 100 sec.sup.-1. It is preferred to combine the additive with the graphite flour and pitch of the matrix during formation of the matrix. This insures uniform dispersion of the additive in the matrix to provide a blend of the additive and matrix. In this connection, a particularly preferred method for preparing the additive/matrix blend is to heat the pitch to a temperature where it is fluid, i.e., between 100.degree. C and 300.degree. C and to mix the additive with the heated pitch. Thereafter the graphite flour is added to the mixture and the mixture is cooled and ground to provide a matrix with the additive uniformly dispersed therein. However, the additive may be combined with the graphite flour or with ground pitch prior to forming the matrix. A uniform dispersion of the additive in the graphite flour, ground pitch, heated pitch or particulated matrix can be effected by suitable low shear mixing apparatus, such as a sigma blade mixer. The matrix and additive blend may be used "as is" to surround nuclear fuel particles which have been preloaded into a mold by injecting the heated matrix into the mold. In this method for making fuel rods, the matrix is heated to a temperature of from about 100.degree. C to about 300.degree. C. Generally, injection pressures of from about 500 psig to about 3000 psig are suitable for injecting the matrix containing the additive of the invention. The matrix and additive blend may also be combined with nuclear fuel particles prior to fabrication to provide a molding mixture suitable for compression in a mold to fabricate nuclear fuel rods. In this method for making fuel rods, the matrix and nuclear fuel particle combination are heated to a temperature of from about 100.degree. C to about 300.degree. C and are then compressed. A fabrication pressure of from about 500 psig to about 3000 psig is generally sufficient to compress the combination and provide a green fuel rod suitable for further heat treatment. In general, the matrix and additive blend comprises from about 20 to about 50 percent by weight of graphite flour, from about 75 to about 30 percent by weight of pitch and from about 0.5 to about 30 percent by weight of additive. The finished nuclear fuel rod comprises from about 55 percent to about 64 percent of nuclear fuel material by volume and from about 45 to about 36 percent of the matrix and additive blend by volume. As used herein all percentages are by weight, unless otherwise expressed. As indicated, the additives of the present invention provides a matrix with a reduced viscosity at fabrication temperatures and also provides a fuel rod with improved resistance to adhesion with a fuel element. Also, the additives of the invention have mold release properties. The use of additives in the matrix enables manufacture of nuclear fuel compacts without the use of mold release materials applied to the surface of the molds. The multi-functionality of the additives of the present invention provides a matrix for use in the manufacture of nuclear fuel compacts with greatly enhanced properties.
061570362	claims	1. A gas-over-eluent, fluid delivery mechanism for eluting one or more processing elements having inlets and outlets, comprising: a reservoir having an output feed at the bottom thereof for connecting to the inlet of one of the one or more processing elements; a predetermined volume of eluent contained in the reservoir; a predetermined volume of gas contained in the reservoir, separated from and positioned over the predetermined volume of eluent; and a force-limited, pressure-supplying mechanism that forces the volume of eluent and then the volume of gas through the reservoir output feed and into and through the one or more processing elements, thereby eluting the one or more processing elements with the predetermined volume of eluent and purging the one or more processing elements with the predetermined volume of gas. the reservoir is a syringe; and the pressure-supplying mechanism includes: at least one processing element each having an inlet and outlet; a reservoir having an output feed at the bottom thereof for connecting to the inlet of one of the at least one processing element; a predetermined volume of eluent contained in the reservoir; a predetermined volume of gas contained in the reservoir, separated from and positioned over the predetermined volume of eluent; and a force-limited, pressure-supplying mechanism that forces the volume of eluent and then the volume of gas through the reservoir output feed and into and through the at least one processing element, thereby eluting the at least one processing element with the predetermined volume of eluent and purging the one or more processing elements with the predetermined volume of gas. preloading the delivery mechanism with a predetermined volume of eluent and a predetermined volume of gas positioned over the volume of eluent; and applying a pressure directly upon the volume of gas to force the volume of eluent followed by the volume of gas through the at least one processing element at a predetermined rate. (a) at least one generator for producing an eluate containing a desired radioisotope to be concentrated; (b) a radioisotope concentration subsystem having at least one processing element in fluid communication with the generator that processes the radioisotope therein; (c) a radioisotope collection vessel in fluid communication with the concentration subsystem for collecting therein a desired volume of prepared radioisotope solution; (d) a first gas-over-eluent delivery mechanism in fluid communication with the generator, that stores a first measured volume of fluid which includes a first measured volume of eluent solution and a first measured volume of a gas positioned over the first volume of solution, the mechanism including a first pressure-supplying source that applies a first pressure upon the first volume of gas to force the first volume of eluent and then gas through the generator and the radioisotope concentration subsystem; and (e) a second gas-over-eluent delivery mechanism in fluid communication with the concentration subsystem, that stores a second measured volume of fluid which includes a second measured volume of eluent solution and a second measured volume of a gas positioned over the second volume of solution, the second mechanism including a second pressure-supplying source that applies a second pressure upon the second volume of gas to force the second volume of eluent and then gas through the concentration subsystem and into the radioisotope collection vessel, thereby re-eluting the radioisotope at a desired concentration. the first delivery mechanism further includes a first, downwardly-positioned syringe having a barrel defining a hollow cavity for containing therein the first volume of fluid and including an outlet, and a plunger placed within the hollow cavity, the first syringe being substantially vertically positioned so that the outlet is at the bottom and the plunger is at the top, and wherein the first pressure-supplying source is connected to the plunger, and the second delivery mechanism further includes a second, downwardly-positioned syringe having a barrel defining a hollow cavity for containing therein the second volume of fluid and including an outlet, and a plunger placed within the hollow cavity, the second syringe being substantially vertically positioned so that the outlet is at the bottom and the plunger is at the top and wherein the second pressure supplying source is connected to the plunger. at least one impurity trap in fluid communication with the generator for removing impurities from the eluate, a radioisotope trap in fluid communication with the at least one impurity trap for concentrating therein the desired radioisotope in the eluate and for permitting the passage of the eluate therethrough for disposal, and wherein the second gas-over eluent delivery mechanism forces the second measured volume of eluent and then the second measured volume of a gas into and through the radioisotope trap and into the radioisotope collection vessel. applying a first pressure on the first volume of gas to force the first volume of eluent and then the first volume of gas through the generator and concentration subsystem and into a fluid waste receptacle, thereby eluting the daughter radioisotope from the generator, concentrating the resultant eluate, and purging the generator, the at least one impurity trap and the radioisotope of eluate; and applying a second pressure on the second volume of gas to force the second volume of eluent, and then the second volume of gas through the concentration subsystem and into the sterile, vented collection vessel, thereby re-eluting the concentrated daughter radioisotope into the collection vessel and purging the concentration subsystem of fluid. at least one eluate processing element; and a sealed, radioactively-shielded, container that houses the at least one eluate processing element, the container having at least one opening and further including, at least one impurity trap; a radioisotope trap serially connected to the at least one impurity trap; and a sealed, radioactively shielded, container that houses the at least one impurity trap and radioisotope trap, the container having at least one opening and further including, a first input septum that seals the first container opening and permits the flow of eluate from the generator into the at least one impurity trap when penetrated by the first fluid delivery system, a second input septum that seals the second container opening and permits the flow of fresh eluent through the radioisotope trap when penetrated by the second fluid delivery system, and an output septum that seals the third opening and permits the flow of the prepared radioisotope solution from the radioisotope trap to the sterile, collection vial when penetrated by the third fluid delivery system. 2. The mechanism of claim 1, wherein: 3. A system for producing a radioisotope solution, comprising: 4. The system of claim 3, wherein the at least one processing element is a radioisotope generator having an input connected to the output feed of the reservoir. 5. The system of claim 3, wherein the at least one processing element includes at least two radioisotope generators connected in series. 6. The system of claim 3, wherein the at least one processing element includes at least one radioisotope generator and at least one of a radioisotope concentration component and radioisotope purification component. 7. A method for eluting a desired volume of a daughter radioisotope solution through at least one radioisotope processing element using a gas-over-eluent delivery mechanism in fluid communication with the at least one processing element, the method comprising: 8. A system for producing a concentrated radioisotope through a series of elution steps, comprising: 9. The system of claim 8, wherein 10. The system of claim 9, wherein the first and second pressure-supplying sources are constant pressure sources. 11. The system of claim 10 wherein the first constant pressure source is a first mass having a predetermined weight and the second constant pressure source is a second mass having a predetermined weight. 12. The system of claim 9, wherein the first and second pressure-supplying sources are variable-rate, pressure-supplying sources. 13. The system of 12 wherein the first pressure supply source is a first spring having a predetermined spring constant and the second pressure supply source is a second spring having a predetermined spring constant. 14. The system of claim 8, wherein the at least one processing element comprises 15. The system of claim 9, further including a waste receptacle for receiving the eluate produced by the generator and passed by the radioisotope trap. 16. The system of claim 15, wherein the waste receptacle is integral with the radioisotope concentration subsystem. 17. The system of claim 8, wherein the first gas-over-eluent delivery mechanism is connected to the second delivery mechanism so that the second pressure-supplying source is applied to the second measured volume of fluid only after the first delivery mechanism is depleted of its first volume of fluid. 18. A method for automatically eluting a desired volume of a daughter radioisotope from a parent radioisotope contained in at least one generator using a first, gas-over-eluent delivery mechanism containing a first measured volume of gas positioned over a first measured volume of eluent, the mechanism in fluid communication with the at least one generator, for automatically concentrating the resultant eluate in a concentration subsystem having at least one impurity trap in series with a radioisotope trap having an inlet and outlet, and for re-eluting a daughter radioisotope solution into a sterile, vented, collection vessel with a second, gas-over-eluent, storage and delivery mechanism containing a second, measured volume of gas positioned over a second, measured volume of eluent, the method comprising: 19. The method of claim 18, further including sensing that the applying of the first pressure on the first volume of gas is completed, and wherein the applying of the second pressure on the second volume of gas commences only upon such sensing. 20. The method of claim 19, wherein the applying if the second pressure is automatic. 21. A single-use, self-sealed, radioisotope concentration cartridge for processing therein a radioisotope contained in an eluate solution generated by a radioisotope generator and carried by a fluid delivery system, thereby preparing the radioisotope to be delivered into a sterile, collection vial, the cartridge comprising: 22. The cartridge of claim 21, wherein the container further includes a visual indicator that identifies whether the container has been used in a prior elution procedure. 23. The cartridge of claim 21, wherein the container further includes a quality control indicator that identifies a condition, such as pH, chemical purity or biological purity, of the eluate contained therein. 24. The cartridge of claim 21, wherein the container is shaped to fit into a radiation well chamber that identifies breakthrough activity of a parent radioisotope from the generator. 25. A single-use, self-sealed, radioisotope concentration cartridge for concentrating therein a radioisotope contained in an eluate solution generated by a radioisotope generator and carried by a first fluid delivery system, thereby preparing the radioisotope to be re-eluted by a second fluid delivery system and to be carried into a sterile, collection vial via a third fluid delivery system, the cartridge comprising: 26. The cartridge of claim 25, wherein the container includes at least three openings and the at least one septum includes 27. The cartridge of claim 25, further including an eluate waste receptacle sealed within the container that is in fluid communication with the output of the radioisotope trap for collecting therein eluate waste from the first elution.
	summary
	description	The invention will now be described in reference to the attached drawings. Referring to FIG. 1, in this embodiment, another alignment mark is exposed and imprinted by ultra-violet rays on a dry film used for patterning a next layer to be built up. A board 5, which is transferred from the preceding process, comprises a circuit pattern 52 formed on a core board 51, an insulation layer 53 formed thereon, a build up copper foil layer 54 formed further for forming a next circuit pattern, and finally a dry film resist layer 55 on top. These multi-layer structures are formed on both sides of the board 5, respectively. In one end of the core board 51 is a copper foil standard mark 50 which is formed simultaneously as the circuit pattern 52 is formed. The board 5 is transferred from the preceding process in this state, and will be placed on a board stage 3. The board stage 3 is movable in the XYZ directions and rotatable in xcex8 degree angle, that allows the board 5 to move in arbitrary directions. The marking apparatus of the invention comprises a standard mark detection device 1, a marking device 2, the board stage 3 described above, and a control device 9. The standard mark detection device 1 is equipped with an X-ray power source 10, an X-ray generator 11, a fluorescence screen 12, and a visible light CCD camera 13. The X-ray generator 11 is positioned in that it irradiates X-rays in the direction of the board 5. The fluorescence screen 12 is placed behind the board 5, thereby receiving the X-rays transmitted from the board 5. The fluorescence screen 12 converts the X-rays to visible light, and projects an image created by the X-rays on its rear side. The visible light CCD camera 13 is placed further below the fluorescence screen 12, thereby photographing the image emerged on the rear side of the fluorescence screen 12 and transmitting it to the control device 9 where appropriate image processing takes place. In the construction described above, the board 5 is placed on the stage 3 and properly positioned within the area of the X-rays to be transmitted from the X-ray generator 11. Then, X-rays are irradiated at the board 5 from the X-ray generator 11, the image of the standard mark 50 is projected on the fluorescence screen 12, the resulted image is photographed by the visible light CCD camera 13 and finally processed by the control device 9 to determine the position of the standard mark 50. The fluorescence screen 12 retracts to a pre-set position upon completion of the mark detection process. Also, the visible light CCD camera may be replaced with a regular II camera. The marking device 2 is movable in the XYZ directions, and by the control device 9 it is placed at the position of the standard mark 50, which is previously detected by the standard mark detection device 1. The marking device 2 comprises an ultra-violet lamp 20, optic fibers 21, mirrors 22 and 23, and photo masks 24, and 25 having alignment marks, respectively. By positioning the mirrors 22 and 23 on the front and back sides of the board 5, respectively, the alignment marks depicted on the photo masks 24 and 25 can be imprinted on the dry film resist layers 55, respectively. Although this embodiment depicts that the alignment mark is imprinted at the position corresponding precisely to the detected standard mark 50, it may also be imprinted at another position in relation to the position of the standard mark 50. The ultra-violet rays, being generated by the ultra-violet lamp 20 and split by the optic fibers 21 and 21, are deflected by the mirrors 22 and 23 to the board 5, and simultaneously impinge upon the upper and lower dry film resist layers 55. In this state, the alignment marks created on the photo masks 24 and 25 by the ultra-violet rays are imprinted on the dry film resist layers 55, respectively. The ultra-violet irradiation turns the dry film resists blue. It has enough contrast for the CCD to capture the mark when it is exposed later by the exposure device. The alignment mark will be aligned with an alignment mark of a photo mask used in circuit-patterning process where the build up copper foil layers 54 will be imprinted with a circuit pattern. Upon completion of the ultra-violet irradiation, the marking device 2 retracts to the originally set position. The dry film resist layers 55 may be replaced with liquid resist layer. Besides the method of pattern imprinting by ultra-violet rays as described above, marking by laser or ink-jet, or even by stamping, may also be possible. FIG. 2 describes an embodiment of said marking apparatus using the ink-jet printing method mentioned above. In this embodiment, the board 5 is built up to the build up copper foil layers 54, on which said mark will be printed directly by the ink-jet printing method. The composition of the standard mark detection device 1 is the same as in FIG. 1. A marking device 2xe2x80x2 is also movable in the XYZ directions, and is moved by the control device 9 to the position where the standard mark 50 is detected by the standard mark detection device 1. The marking device 2xe2x80x2 is equipped with ink-jet heads 26 and 27 which are positioned on both sides of the board 5, respectively, and spurt ink at the board 5 almost simultaneously to print the mark on the build up copper foil layers 54. Again in this embodiment, the alignment mark is printed at the corresponding position to the detected standard mark 50, but it may also be printed at another position in relation to the position of the standard mark 50, like the embodiment in FIG. 1. In the embodiments described in FIGS. 1 and 2, the standard mark detection device 1 and the marking device 2 or 2xe2x80x2 are arranged in the upper-lower direction relative to the board 5. However, it is also possible to vertically arrange all of the standard mark detection device 1, the marking device 2 or 2xe2x80x2, and the board 5. Also, instead of moving the standard mark detection device 1 and the marking device 2 or 2xe2x80x2, the board 5 may be made movable, or even both of them. As described above, said marking apparatus of the invention will allow alignment marks to form on said conductive layers or on said resist of dry films, etc. for patterning said next build up layers to be formed in relation to the standard mark 50. Therefore, in the succeeding patterning process, any exposure devices currently in use can be used to render a regular exposure process. The invention will eliminate such inefficient processes as removing the copper foils corresponding to said mark on said core board after applying said build up layer copper foil, removing the masking tapes applied to prevent copper plate from covering over the mark on the core board in case a copper plating method is used to form the build up layers, and preventing resin from spilling into the hole or removing spilt resin from the hole when forming the insulation layer of the build up layers in order to prevent the hole from being covered in the succeeding plating process in case a hole instead of a pattern is used as the mark in the core board. The invention will not require purchase of a new exposure device comprising an X-ray generator and an imaging camera. The exposure device currently in use can be used with the apparatus of the invention, therefore a considerable improvement is expected in the capital investment and in the efficiency of multi-layered printed circuit board production. As described above, said marking apparatus of the invention will allow another alignment mark to form on each layer of a multi-layered printed circuit board in relation to said standard mark, therefore it will be possible to improve the alignment precision needed to produce high quality multi-layered printed circuit boards, and to simplify such production processes and equipment.
042959357	claims	1. In a fuel assembly of the type that is employable in a nuclear reactor core and has a definable exterior surface, the fuel assembly including a multiplicity of fuel rods and at least one nuclear fuel assembly spacer grid, said nuclear fuel assembly spacer grid including perimeter means and first and second means each structurally associated with said perimeter means, said perimeter means including a plurality of perimeter strips each made of zircaloy and having their ends interconnected together to form a closed perimetric structure positioned in surrounding relation to said multiplicity of fuel rods thereby defining the exterior surface of the fuel assembly, said first means being operable to provide lateral support to said multiplicity of fuel rods, said second means being operable to effect the proper spacing between said multiplicity of fuel rods, the improvement comprising expandable means cooperatively associated with said perimeter means so as to be operable to preclude in-reactor bowing of the fuel assembly, said expandable means comprising a plurality of expandable strips each being formed from a material having a high thermal coefficient of expansion than zircaloy, said plurality of expandable strips being attached to said plurality of perimeter strips in equally spaced relations one to another, said plurality of expandable strips being thermally expandable between a first position wherein said plurality of expandable strips are located in relatively close proximity to the exterior surface of the fuel assembly and a second position wherein said plurality of expandable strips are displaced laterally relative to the exterior surface of the fuel assembly so as to preclude in-reactor bowing of the fuel assembly by occupying the space adjacent to the exterior surface of the fuel assembly otherwise available for receiving portions of the fuel assembly that have undergone bowing. 2. In a fuel assembly, the improvement of expandable means as set forth in claim 1 wherein each of said plurality of expandable strips comprises a stainless steel strip formed of a material selected from amongst the 300 series stainless steels. 3. In a fuel assembly, the improvement of expandable means as set forth in claim 2 wherein said plurality of expandable strips is attached to said plurality of perimeter strips by having portions of each of said plurality of expandable strips welded to other portions of the same one of each of said plurality of expandable strips. 4. In a fuel assembly, the improvement of expandable means as set forth in claim 1 wherein said plurality of expandable strips are attached to said plurality of perimeter strips so that the major axis of each of said plurality of expandable strips extends substantially perpendicular to the major axis of each of said plurality of perimeter strips. 5. In a fuel assembly, the improvement of expandable means as set forth in claim 3 wherein said plurality of expandable strips are attached to said plurality of perimeter strips so that the major axis of each of said plurality of expandable strips extends substantially parallel to the major axis of each of said plurality of perimeter strips. 6. In a fuel assembly of the type that is employable in a nuclear reactor core and has a definable exterior surface, the fuel assembly including a multiplicity of fuel rods and at least one nuclear fuel assembly spacer grid, the outermost rows of said multiplicity of fuel rods defining the exterior surface of the fuel assembly and at least selected ones of said multiplicity of fuel rods located in said outermost rows of said multiplicity of fuel rods each embodying at least one portion thereof that is devoid of fuel, each of said selected ones of said multiplicity of fuel rods being encased in an all-zircaloy cladding, said nuclear fuel assembly spacer grid including perimeter means and first and second means each structurally associated with said perimeter means, said perimeter means being positioned in surrounding relation to said multiplicity of fuel rods, said first means being operable to provide lateral support to said multiplicity of fuel rods, said second means being operable to effect the proper spacing between said multiplicity of fuel rods, the improvement comprising expandable means cooperatively associated with said selected ones of said multiplicity of fuel rods so as to be operable to preclude in-reactor bowing of the fuel assembly, said expandable means comprising a plurality of sets of expandable strips each including a pair of circularly configured expandable strips mounted in equally spaced relation one to another on said one portion of each of said selected ones of said multiplicity of fuel rods and in circumferentially surrounding relation thereto and an interconnecting expandable strip having one end thereto affixed to one of said pair of circularly configured expandable strips and the other end thereof affixed to the other one of said pair of circularly configured expandable strips so that the major axis of said interconnecting expandable strip extends substantially parallel to the major axis of said selected ones of said multiplicity of fuel rods, said pair of circularly configured expandable strips and said interconnecting expandable strips of each of said plurality of sets of expandable strips being formed of a material having a higher thermal coefficient of expansion than zircaloy, said plurality of sets of expandable strips being thermally expandable between a first position wherein said interconnecting expandable strips are located in relatively close proximity to the exterior surface of the fuel assembly and a second position wherein said interconnecting expandable strips are displaced laterally relative to the exterior surface of the fuel assembly so as to preclude in-reactor bowing of the fuel assembly by occupying the space adjacent to the exterior surface of the fuel assembly otherwise available for receiving portions of the fuel assembly that have undergone bowing. 7. In a fuel assembly, the improvement of expandable means as set forth in claim 6 wherein said pair of circularly configured expandable strips and said interconnecting expandable strip of each of said plurality of sets of expandable strips each comprises a stainless steel strip formed of a material selected from amongst the 300 series stainless steels.
051669625	abstract	An X-ray mask includes an X-ray transmitting thin film consisting of SiC, a W X-ray absorber formed on one surface of the thin film and having a predetermined pattern, and a support frame arranged on a peripheral portion of the thin film. The thin film is constituted by a plurality of SiC layers having different C/Si composition ratios. When the thin film is formed by a CVD method, the flow rate of a gas containing Si is fixed while a gas containing C or a diluted gas mixture of the gas containing C is changed. Consequently, the visible light transmittance of the thin film is improved.
	abstract	A plurality of first plate members 10 is stacked with long side ends 10LT1 and 10LT2 thereof abutting to each other. Plate member joint bodies 100 are formed by attaching connecting members 30 to side surfaces 10S of the stacked first plate members 10, and connecting the first plate members 10. Further, the plate member joint bodies 100 are so disposed to face each other, and the connecting members 30 projecting from the side surfaces 10S of the first plate members 10 are inserted into recesses formed at both long side ends of second plate members 20. A recycled fuel assembly storage basket 1 is thus formed. Recycled fuel assemblies are stored in spaces surrounded by the first plate members 10 and the second plate members 20.
	summary
	claims	1. A closed vessel for a radioactive substance, comprising: a substantially tubular vessel body closed at the bottom, having a top opening, and configured to contain radioactive substance in a shielded state; and a lid set in the top opening of the vessel body and welded to the inner peripheral surface of the vessel body, the lid having an outer peripheral portion adjacently opposed to the inner peripheral surface of the vessel body, the outer peripheral portion including a welding portion welded to the inner peripheral surface of the vessel body and a groove formed on the outer peripheral portion throughout the circumference and defining a space portion which is located toward the bottom side of the vessel body with respect to the welding portion and which faces the inner peripheral surface of the vessel body, the space portion being configured to be filled with a shield gas or to allow the flow of the shield gas therein so as to shield the welding portion from the interior of the vessel body, as the welding portion is welded. 2. A closed vessel for a radioactive substance according to claim 1 , wherein the lid has a discharge hole through which air is simultaneously charged into and discharged from the vessel body as the welding portion is welded. claim 1 3. A closed vessel for a radioactive substance, comprising: a substantially tubular vessel body closed as the bottom, having a top opening, and configured to contain radioactive substance in a shielded state; a shielding plate set in the top opening of the vessel body and closing the top opening; a seal member for sealing a gap between the inner peripheral surface of the vessel body and the shielding plate; and a lid set in the top opening of the vessel body so as to be lapped on the shielding plate and having a peripheral edge portion welded to the inner peripheral surface of the vessel body, the lid having an outer peripheral portion adjacently opposed to the inner peripheral surface of the vessel body, the outer peripheral portion including a welding portion welded to the inner peripheral surface of the vessel body and a groove formed on the outer peripheral portion throughout the circumference and defining a space portion which is located toward the bottom side of the vessel body with respect to the welding portion and which faces the inner peripheral surface of the vessel body, the space portion being configured to be filled with a shield gas or to allow the flow of the shield gas therein so as to shield the welding portion from the interior of the vessel body, as the welding portion is welded. 4. A closed vessel for a radioactive substance according to claim 3 , wherein the lid and the shielding plate have a discharge hole through which air is simultaneously charged into and discharged from the vessel body as the welding portion is welded. claim 3 5. A closed vessel for a radioactive substance according to claim 3 , which further comprises a support portion located on the inner peripheral surface of the vessel body near the top opening and a frame-shaped support plate placed on the support portion, and wherein the shielding plate is placed on the support plate, and the seal member has an O-ring provided between the shielding plate and the support plate. claim 3
048760633	summary	BACKGROUND OF THE INVENTION This invention relates to fuel bundles. More particularly, this invention relates to an improved water rod for placement interior of the fuel assembly, the fuel assembly having a preferred 9 by 9 array of rods. SUMMARY OF THE PRIOR ART Fuel assemblies are known. Typically, such fuel assemblies include a lower tie-plate, an upper tie-plate, and a surrounding channel therebetween. The channel usually has a square cross-section. In the square cross-section are placed fuel rods. Preferably these fuel rods are placed in rows and columns. In boiling water nuclear reactors, water serves as a moderator. That is to say the water converts fast neutrons produced by an atomic reaction to slow neutrons. These slow neutrons in turn produce the desired atomic reaction. Typically, the process of the production of the atomic reaction, the production of the fast neutrons, the moderation of the neutrons with following production of atomic reaction endlessly reoccurs. The desired heating reaction results. Interior of fuel bundles it is desired to increase the amount of moderator present. Specifically, in modern fuel bundle assemblies it has been found desirable to place along the interior of the fuel bundle larger volumes of water. These larger volumes of water typically displace fuel rods. The fuel rods when displaced have their volume occupied by water. The presence of the increased volume of water provides optimum moderation of the reaction within the fuel rods. In order to provide water in a single phase and separate the provided water from the two phase steam water mixture, it is common to introduce such water in so-called "water rods". This invention relates to a water rod. SUMMARY OF RELATED DISCLOSURES (NOT PRIOR ART) In certain nuclear fuel bundle designs, the use of a 9 by 9 fuel rod array is optimal. However, the placement of volumes of moderating water within water rods has not been without difficulty. The cross-sectional area made available by removing the fuel rods has an irregular shape. For nuclear and thermal/hydraulic design efficiency, the water rod (or rods) should occupy as much of this area as possible. However, for minimum cost a simple cross-sectional shape is desirable; preferably circular or nearly circular. The desirability for such a 9 by 9 array of rods can be seen in U.S. patent application No. 176,975, filed Apr. 4, 1988 entitled Two-Phase Pressure Drop Reduction BWR Assembly Design, assigned to the Assignee herein. SUMMARY OF THE INVENTION In a nuclear fuel bundle having a lower tie-plate, an upper tie-plate and a surrounding channel therebetween, an improved water rod is disclosed for preferable use when fuel rods held between the tie-plates are placed in a 9 by 9 array. Typically, seven fuel rods are omitted centrally of the 9 by 9 array with the middle or fifth row having three rods removed and paired rods being removed in the 4th and 6th row with displacement of the removed pair towards opposite corners. Into the volume created by the removed rods, tbere are placed two "D" sectioned rods, the "D" rods each being cylindrical except for a truncating chord eccentrically located beyond the diameter of the rod, this truncating chord defining the straight back of each "D". In the preferred embodiment one of the "D" water rods is provided with spacer tabs for maintaining spacers separating the fuel rod at their correct elevations. This rod is inserted with an alignment that permits the tabs to pass through the spacers. When the rod is fully inserted, it is rotated to a locking alignment so that the tabs capture the spacers. In this locked alignment, the straight back of the "D" is aligned to confront the straight back of the confronting "D" on the second water rod. When the second "D" rod is inserted with the backs confronted mutual, locking of both "D" sectioned water rods occurs. Provision is made for narrowing of the upper and lower sections of the water rods. The upper and lower portions of the water rods are cylinders of reduced diameter which are joined to the central "D" section by transition pieces. Upper and lower end plugs are used for locating the complete water rod in the upper and lower tie plates, respectively. There results a pair of water rods which provides for efficient utilization of the available space, has low manufacturing costs, and provides for spacer capture enabling ease of assembly and disassembly of the fuel bundle. OTHER OBJECTS, FEATURES AND ADVANTAGES An object of this invention is to disclose placement of water rods in a 9 by 9 array of fuel rods contained within a square section channel. According to this aspect of the invention, the central row of fuel rods has three fuel rods displaced. On the periphery of the displaced central fuel rods and to and towards opposing corners, paired rods are removed. A total of seven rods are removed. Into this region there are placed two D-sectioned rods, the rods being circular except for a truncating chord wall. This truncating cord defines the straight back that gives the disclosed water rod a "D" profile. Two "D" section rods are placed with their backs confronting one another. An advantage of this aspect of the invention is that the "D" section rods are both easy to fabricate and conveniently occupy a large fraction of the volume of the displaced seven fuel rods from the 9 by 9 array. An additional aspect of this invention is to arrange for the support of the fuel element spacers. According to this aspect of the invention, one of the "D" section rods is provided with protruding spacer support tabs. These tabs are sized and aligned with respect to one "D" sectioned water rod to pass through spacers in one angular orientation and to lock to the spacers in another angular orientation of the rod with respect to the spacers. The water rod with the tabs is inserted at an alignment which permits the tabs to pass through the spacers. When the rod is fully inserted, it is rotated to a tab locking orientation so that the tabs capture the spacers. In this locking alignment, the straight back of the "D" is aligned to confront the straight back of the "D" on the second water rod. When the second water rod is inserted, with the straight back for the insert "D" rod confronted to the back of the first "D" sectioned rod, the two "D" water rods lock in rotational and supporting alignment. An advantage of this aspect of the invention is that both the assembly and disassembly of fuel bundles utilizing the water rods in this invention can easily occur. At the same time, the water rods cooperate in mutually locking relationship in maintaining spacer distribution within the fuel bundle.
	summary
	description	I claim benefit of provisional application 61/134,867 filed Jul. 15, 2008. The field of invention is nuclear radiation protection. The invention solves the problem of a low weight nuclear radiation shield able to ensure an increased protection, equivalent to that produced by a more massive shield, when the radiation comes from fluctuating sources with well defined positions in the space. The solution to the problem. The increase in protection is obtained by using an adaptive shield, with mobile elements and with adaptive shape, orienting the mobile elements in such a way as to produce the absorption required in the specified direction. 1. Discussion of the Background Art State of the art. Many designs of fixed, mobile or portable passive i.e. absorption—or “active” electrostatic or magnetic—i.e. deflecting—nuclear radiation shields are known in the literature, to protect the personnel and equipment from nuclear radiation coming from sources on the Earth, from the Sun, or from the cosmos. These shields are aimed to protect personnel and equipment from harmful nuclear radiation, including X radiation. In general, these shields are omni-directional, in the sense that they attenuate evenly radiation coming from any direction of space. The disadvantages of these shields are that they are massive and that they offer enough protection only when they have a large thickness and correspondingly high mass. Such shields are costly and, because of their high mass, are difficult to be used in space systems and, generally, in mobile systems. The known shields also have the disadvantage of the total lack of adaptability to the possible changes of the external radiation sources. Especially for vehicles, for which the volume occupied by the equipments and the weight are essential factors, heavy and bulky shields are impractical. Moreover, for vehicles, the direction and the amplitude of the radiation sources are fluctuating and, in general, are unknown. Such vehicles are space vehicles, mobile radiological laboratories for medical or industrial use, and de-contamination vehicles. For such cases, an adaptive shield is needed. Space vehicles represent a special case, as they require radiation shields adaptive to changes in the level of cosmic radiation. The adaptation could reasonably reduce temporarily the protected space in case of intense radiation, such that the protection is ensured for the personnel and for the most critical equipment, even if the comfort is decreased. Adaptive shields are also needed in the case of terrestrial vehicles, to ensure protection depending on the conditions on the terrain. Moreover, in the case of surface exploration vehicles, the shielding system will have to adapt to the Sun's movement relative to the planet's surface. Space stations can be considered a specific type of space vehicle, where long-duration stays make astronauts especially vulnerable to radiation. It is known that space stations, such as ISS, must be provided with “safe areas” where the personnel on the station can take refuge when dangerous solar or galactic radiative events occur. Vehicles for long space travels and stations on other planets or on satellites, as planned today for the near future, need safe areas that are well shielded to offer protection to the personnel under extreme space weather. In general, in all situations where variable radiation sources are encountered, adaptive shields are required to achieve an optimal balance between the radiation protection and the volume of the protected space. Even only for the psychical “safety” condition of people working in radiation conditions, such a shield would be desirable and useful. It is known that space systems can be exposed, for short periods of time, to very intense fluxes of radiation, which come from well-defined directions from space, as the Sun or a particular galaxy. Such events happen during solar flares or during strong extra-solar nuclear activity—galactic or extragalactic, as supernovae explosions. Under these conditions, personnel or critical equipment onboard space systems are in major hazard. The hazard—probability of irradiation over a maximum acceptable dose—rises in case of extended space travel. Moreover, the inception and the development of space industrial activities and of space tourism impose reconsidering the problem of irradiation risks and of designing radiation shields that provide protection to passengers in conditions of large variability of space irradiation. It is known that outside the space protected by Earth's magnetic field—outside the magnetosphere—radiation can accidentally become very intense. For example, it is known that between the missions Apollo 16 and 17, a strong proton radiation was produced, which, if astronauts were on route to the Moon, would have irradiated them with a lethal dose in less than 10 hours. It is also known that, during solar flares, X radiation—band 1.0-8.0 Angstrom—can reach the flux of 10−3 W/m2, while in the absence of solar flares, its value is around 10−7 W/m2—NASA, http://science.nasa.gov/headlines/y2000/ast14jul—2m.htm. Such increases, of up to four orders of magnitude, over short periods of time—minutes or hours—may endanger the lives of passengers of a space station, or space vehicle. Due to the fact that radiation events are both rare and unpredictable, protection through massive omni-directional shielding is too costly. The cost of a radiation shield is a major factor in all instances in which radiation protection is required. In the case of shielding vehicles or portable equipment—for example, radiation protection clothing—mass is an essential factor. The problem exposed above is extensively dealt with in the recent volume “Space Radiation Hazards and the Vision for Space Exploration. Report of a Workshop” by the Ad Hoc Committee on the Solar Radiation Environment and NASA's Vision for Space Exploration; National Research Council of the National Academies, http://books.nap.edu/openbook.php?record_id=11760&page=R1, accessed Jan. 2, 2007). Similar problems are encountered on satellites that carry sensitive electronic equipment that must be protected in case of intense solar or cosmic radiation. Thus, in space applications, it is important to use shields with reduced mass, which will ensure protection according to necessity, that is, it is important to use adaptive shields. The solution currently used onboard space systems is an omni-directional shielding that ensures radiation protection inside a small portion of the spacecraft, where personnel can retreat in case of a significant increase in irradiation. Similar problems arise in the field of terrestrial installations. While power grid failures induced by space radiation are largely known to occur due to the high currents induced in the cables due to the change in the magnetic fields, some equipment such as transformers are known to be the most vulnerable. It is not yet well understood if the direct radiation plays a part in the failure of power transformers; but it is known that a direct radiation hit is able to change the properties of the oils in the transformer and thus it could prove that the direct radiation hit may also play a role in the power grid failures. Therefore, it may be of interest to shield such equipment to radiation. Because the radiation direction is not fixed, an adaptive shield may also be beneficial for protecting power equipments. Various designs of radiation shields are known in the literature. These shields can be fixed, mobile, or even portable. Such shields are used in a variety of applications. Examples of shield designs are (Radiation protection shield for electronic devices. Inventor: Katz Joseph M. US2002074142-2002-06-20), (Radiation protection concrete and radiation protection shield. Inventor: Vanvor Dieter. TW464878-2001-11-21), (Radiological shield for protection against neutrons and gamma-radiation, Riedel J., GB1145042-1969-03-12), (Shield for protection of a sleeping person against harmful radiation. Inventor: Jacobs Robert. U.S. Pat. No. 4,801,807-1989-01-31), (Shaped lead shield for protection against X-radiation. Inventor: Hou Jun; Yunsheng Shi. Applicant: Hou Jun, CN2141925U-1993-09-08), (Filter for X Radiation, Inventor Petcu Stelian, 30.07.1996, Patent RO 111228 B1), (Radiation Passive Shield Analysis and Design for Space Applications, International Conference on Environmental Systems, Horia Mihail Teodorescu, Al Globus, SAE International, Rome, Italy, Jul. 11-15, 2005. SAE 2005 Transactions Journal of Aerospace, 2005-01-2835, March 2006, pp. 179-188). Other designs can be similar to designs of shields for other types of radiation; such designs are provided in (Shield device for the rear protection of an infrared radiation emitter apparatus, tubes and shields for implementing it. Inventor: Lumpp Christian, FR2554556-1985-05-10), (Shield for protection against electromagnetic radiation of electrostatic field. Inventor: Sokolov Dmitrij Yu.; Kornakov Nikolaj N., Applicant: Sokolov Dmitrij Yu.; Kornakov Nikolaj N., SU1823164-1993-06-23). All these designs are for fixed shields. Also, many materials and combinations of materials are known to be effective in radiation protection, for example (Patent RO 118913 B, Multi-layer screen against X and gamma radiation, Moiseev T., 30.12.2003), (Patent RO 120513 B1, X-ray absorbing material and its variants, Inventors: Tkachenko Vladimir Ivanovich, U A.; Nosov Igor Stepanovich, Ru; Ivanov Valery Anatolievich, U A; Pechenkin Valery Ivanovich, U A; Sokolov Stanislav Yurievitch, L V., 28.02.2006). Also, there are many manufacturers of radiation shielding plates and materials, for example (X-ray Protection Screen, Data Sheet, Apreco Limited, The Bruff Business Centre, Suckley, Worcestershire, WR6 5DR, UK., www.apreco.co.uk), (Premier Technology Inc., 170 E. Siphon Rd. Pocatello, Id. 83202, USA, Shielding Windows & Glass—Information & Tutorials, RD 50 X-Ray Protection Glass http://www.premiertechnology.cc/premier/RD50.cfm). In a recent publication, “Space Radiation Hazards and the Vision for Space Exploration—Report of a Workshop”, Committee on the Solar System Radiation Environment, Space Studies Board, Division on Engineering and Physical Sciences, National Research Council of the National Academies, 2006, Washington D.C., www.nap.edu, in Section “Operational Strategies for Science Weather Support”, p. 47, FIG. 3.4, (http://books.nap.edu/openbook.php?record_id=11760&page=47), among other means for reduction of radiation, the following are proposed: passive shielding, [radiation] storm shelters, and reconfigurable shielding.” However, no example of reconfigurable shielding is provided. The solution we propose goes beyond simple reconfiguration, moreover proposes a specific way to improve the efficiency of the shielding, while preserving the weight of the shielding as low as possible. The necessity of fast deploying radiation shields whose shape is modifiable according to necessities was recognized and shields have been proposed that are composed of several movable shielding plates that can be position according to the necessity (Baudro, 1987), (Toepel, 2003). However, the arrangement of the component panels of the shield remain empirical and no specific manner of arranging them in connection to radiation dose minimization was presented in the patents (Baudro, 1987), (Toepel, 2003). On the other hand, the minimization of the harmful radiation dose is a well established goal in medical applications of the nuclear diagnosis and treatment. The achievement of that goal was pursued in various technical solutions for the case of medical applications, especially for variable collimators (Short, 2005). Variable shape, reconfigurable collimators were proposed to achieve the said purpose. Short (Short, 2005) presented a radiation shield with variable attenuation that is essentially able to partly or completely interact with the radiation moreover that can change its structural properties at a microscopic scale in order to change its radiation attenuation. Short teaches a shield that is able to produce only intermediate levels of attenuation, between the attenuation provided when the slabs are perpendicular to the radiation propagation direction and zero attenuation. However, the problem of applying specified distributions of radiation doses to specified parts of the patient body while using a radiation source or sources with well known positions and the problem of minimizing the radiation dose to personnel or equipment when the distribution of the radiation sources and the fluxes produced by the said sources are unknown and variable require different methods for reconfigurable the shielding. A highly adaptive reconfigurable shield and an appropriate adaptation method are needed in case of shielding against unknown, time-variable radiation sources as encountered in space. The adaptation should be performed for minimizing the radiation dose in the space delimited by the shield, while the space delimited by the shield must be at least a specified space to accommodate the protected personnel or the equipment. The solution we propose solves the requirements above presented while departing from the known reconfigurable shields or collimators previously known. The solution relies on a specific way to improve the efficiency of the shielding by changing the arrangement of the shield elements, yet preserving the weight of the shielding as low as possible, where the improvement is obtained solely by increasing the thickness of the shield as apparent to the incident radiation. 2. The Technical Problem the Invention Solves The first technical problem solved is the design of an adaptive radiation shield able to ensure an increased protection to radiation, especially when the radiation intensity and the direction from which the radiation comes are changing. The second technical problem solved is the design of the said adaptive radiation shield with a lower mass than a fixed shield made of the same materials. The adaptive radiation shield and its constructive variants, as subsequently presented, according to the invention, solves the above-mentioned problems and eliminates or reduces the disadvantages of the classic designs. Our solution(s). The object of this invention constitutes an adaptive, directional radiation shield, capable of realizing—with relatively low mass—an elevated attenuation of radiation in a reduced space when the level of external radiation fluctuates either in intensity, direction of source, occurrence of multiple sources, or in nature of radiation. The protected space will have variable dimensions, correlated with the intensity of the external radiation, such that, at a given level of external radiation and a given maximum dose admitted in the interior portion, it will have the largest volume. The shield is specially conceived to ensure protection in well-defined directions, specifically in directions of incidence of radiation coming from variable sources—placed at large distances, such as the Sun—or from sources that spontaneously emit strong doses of radiation. The solution to the stated problems is based on the local adaptation of the shape of the shield and the increase of the radiation by the movement of the elements composing the shield such that the apparent thickness of these elements increases in the direction of the incoming radiation. The shield produces a radiation absorption that varies for different directions of the incoming radiation, the adaptation consisting in increasing the absorption in the direction of the actual incoming radiation. The protected space may be slightly diminished during the adaptation. The shield is aimed to adapt to strong and variable radiation sources placed at large distances, like the Sun and other celestial radiation sources. The principal physical-geometrical effect explaining the operation of the adaptive shield consists in that that the change of position of an elongated body with respect to the direction of the incident radiation modifies the apparent thickness seen by the radiation and thus modifies the radiation absorption of the primary radiation. By building the shield with an ensemble of such elongated elements and by adjusting their position with respect to the incident radiation, an adaptive shield can be built. The position control can be performed in different manners, some of them exemplified in the present invention description. The mobile elements can be macroscopic parts of the shield, like plates or slabs, or can be microscopic elements constituent of the material of the shield, like in a ferro-fluid. In the second case, the material of the shield behaves as a controllable anisotropic material with respect to the radiation absorption. In a non-limitative version of realization, the radiation shield proposed herein consists of a set of articulated plates, slats or slabs, for example articulated with hinges, or with elastic articulations, such that the relative positions of the plates can be modified. The adaptive shield also includes radiation sensors, the necessary radiation measuring circuitry, a control system that controls the positions of the plates, and actuators to change the positions of the plates. In a non-limitative example of realization, the plates can have plane-parallel (thin parallelepiped, slat-, slab-) shape, and the assembly of plates encloses and protects an inside space of desired shape, for example, parallelepiped or cylindrical shape. The main operating principle of the adaptive shield is described below. By modifying the tilt of the plane of an absorption plate with respect to the direction of incident radiation, the apparent width of the plate, as seen by the radiation, that is, the distance traveled by the primary radiation through the plate, is modified. Namely, if the actual width of the plate is d, then by inclining the plate with an angle θ, the distance traveled by the radiation through the plate becomes δ(θ)=d/\|cos θ\|. At large inclination angles, the equivalent increase of the absorption depth may increase by a factor of 10 with respect to the actual width of the plate. Consequently, the attenuation of the primary radiation is correspondingly increased. In this description, we do not analyze the problem of secondary radiation, which can be dealt with using appropriate materials known to the art for a two-section shield. The absorption produced by the plate is governed by the absorption lawΦ(θ)=Φ0·e−kδ(θ) where k is the absorption coefficient, which is dependent of nature of the radiation, of the spectral composition of the radiation and of the nature of the absorption material of the plate. Above, Φ0 is the incident radiation flux, and Φ(θ) is the radiation flux passing beyond the shield, at an inclination angle θ of the plate with respect to the incident radiation. For example, for an inclination of 60° of the plate with respect to the direction of the incoming radiation, δ(θ)=2d, therefore the attenuation increases by a factor ofe−kd/e−2kd=ekd with respect to the case of the plate normal to the radiation direction. For large inclinations, for example of 80°, one obtains δ(θ)=d/\|cos θ\|≈5,75·d. Correspondingly, a reduction of radiation by a factor of e4.75d is obtained, compared to the case of normal incidence of the radiation. The absorption plates may be realized of materials with uniform composition and absorption, or from composite materials, or of layers of different absorption materials, or of several plates with different absorption properties, in such a way as to efficiently absorb both the primary and the secondary radiation. The adaptive shield invention does not claim any specific material for shielding. Any known radiation-absorbent material can be a candidate for the design of the plates composing the shield. The purpose of the invention describing the basic shield with movable plates is to improve the efficiency of shields in an adaptive manner, not to devise new materials for shields. Subsequently, in connection to FIGS. 1, 2 and 3, we present a non-limitative example of realization for the adaptive radiation shield and we describe the operation and adaptation principle. FIG. 1 illustrates a non-limiting example of shield composed of radiation absorption plane-parallel plates (1), slates or slabs, connected through joints (2). The joints (2) can be any type of hinge, mechanical joint, or elastic articulation that allows the relative change of position of the plates, slabs or slates (1). The assembly of the plates is forming the adaptive shield (3). The sketch in FIG. 1 represents a non-limiting version of the adaptive shield that initially delimits a space of square transversal section. As a consequence of the increase of an incident radiation (4), the shield modifies its shape in order to reduce the effect of the radiation in the delimited protected space. The plates attenuate the incident radiation (4) in order to reduce the level of the internal radiation (5) to an acceptable level, thus protecting the inside space (6) delimited by the shield. FIG. 2 illustrates the distance (7) traveled by the radiation through the plates, distance that represents the effective, apparent (not geometrical) thickness of the shield. That thickness is modified by the inclination of the plate with respect to the incident radiation, by a factor of 1/\|cos θ\|. In this way, the radiation that penetrates in the protected space is reduced. The assembly of plates (1) of the adaptive shield (3) can take the form of a spatial zigzag, with variable angles between the articulated plates, as illustrated in FIG. 3. The articulations can be made with hinges or with elastic materials, or with any other known means. Various configurations of the shield and shield plates can be used. As a matter of example, FIG. 4 shows a shield formed of equilateral plates that compose a hexagonal tile. This tiling configuration allows the deformation of the shield in three directions, allowing for more adaptability, which is very convenient when the direction of the radiation changes. FIG. 5 illustrates how a regular polygonal section of the shielding allows for a large interval of values for the angle between the plates, when transforming the convex polygonal section into a non-convex one. In FIG. 6 it is shown that a shielding folding based on a pattern of non-isosceles triangles (in cross-section) allows an improved attenuation by increasing the apparent thickness of the shield. Such patterns of non-isosceles triangles can be formed using slabs of the same width, but with a non-identical folding angle. Also in FIG. 6, upper panels, right, it is illustrated how slabs articulated by sliding hinges can deform to increase the apparent thickness. FIGS. 7 and 8 show various geometries of protected spaces and various types of shields with different deformation patterns; such cases can suit a large range of applications. The position of the assembly of plates (1) that form the radiation shield (3) is automatically controlled by a measuring system that monitors the incident radiation at the exterior of the shield. The system may also measure the radiation entering in the interior of the shield. In conformity with these measured values, a control system and the related actuating (driving) devices adjust the position of the plates of the shield with the aim of reducing under an acceptable limit the radiation that enters the protected region. The control system includes for this purpose radiation sensors (8) placed externally with respect to the protected region, and possibly sensors (9) placed in the protected region (6). The sensors also determine the direction from which the dominant radiation flux comes, such that the protection is produced preferentially toward that direction. The control system comprises, as sketched in FIG. 9, apart from the external (8) and internal (9) directional radiation sensors, a measuring system (circuits annexed to the sensors), and a digital control system (10), moreover a system (11) of actuating/driving the elements of the shield. The actuation system (11) may be mechanical, pneumatic/hydraulic, magnetic, electrodynamic, or of different nature. The automatic control system of the shield computes the optimal inclination angle for each of the plates, taking into account the radiation levels inside and outside the plate, as well as the geometrical constraints of the plate assembly. Apart from determining the optimal geometrical configuration of the plate system, the control system commands accordingly the plates' actuation system. The actuation system may be based on hydraulic or pneumatic pistons, or on electric motors and gears, or on systems known from the automatic curtain manufacturing, or on electromagnetic actuating systems. The need for sensors to the inside of the protected space, possibly of sensors carried by the personnel, is due to the fact that the radiation in the protected space may vary from point to point, moreover secondary effects may be produced, such as the secondary radiation produced from the shield or from objects inside the protected space. In a non-restrictive construction variant, the sensor is replaced by an assembly of sensors, as sketched in FIG. 10, mounted on a mobile support (12) such that, by the movement of the support, the sensor can scan and monitor a wide solid angle for the incoming radiation. In yet another non-restrictive construction variant, instead of a single sensor, several sensors are used in a sensor array, mounted on a mobile support (12), the sensors comprising a plate (13) of pre-determined thickness realized from the same material or materials as the shield, a protecting shield (14) that prevents radiation from undesired lateral directions to penetrate to the actual sensor (15), the actual (electronic) sensor (15) being included in a sensor chamber (16) which, in a realization version, can consist of a phantom to model the absorption properties of the human body or of the equipment to be protected. The different thicknesses of the sensor shields (13) correspond, from the point of view of radiation dampening, to the dampening produced by specified shapes of the reconfigurable shield. The sensors may also be included in phantoms—such as to determine the radiation effect on the human body, rather than the radiation's physical effect. The use of phantoms is motivated by the need to determine overall—primary plus secondary—radiation effects. The energetic spectral information, total—primary plus secondary—internal radiation flux, and the direction information, are all fed to the controller in order to determine the best shape the adaptive shield must take. The adaptation of the reconfigurable shield is performed according to a radiation dose minimization criterion with restrictions. The restrictions are related to the maximal dose in any of the monitored points in the space delimited by the shield. As a matter of example, in case the shield protects a single person, the dose in various regions of the body of the person must all be submitted to a radiation dose less than a specified value, while the sum of doses received by the whole body must be minimized. Assuming the radiation is monitored inside the delimited space by sensors connected to the head, upper abdomen, lower abdomen and legs, the optimization problem with restrictions is expressed as: Reconfigure shield such that to minimize the total dose ΣkDkwksubject to the conditions Dk<Dk—MAX, where Dk are the measured doses per unit surface in the body region k, Dk—MAX are the corresponding maximal doses allowed, and wk are weights related to the total surface of the corresponding region of the body. This method of adaptation differs to those previously proposed. Baudro invented a radiation shield composed of interconnected slants, which can be easily deployed, the deployed shield having a support that is also collapsible and easily deployable. The deployed shield has essentially a predetermined planar shape and, according to the drawings in the quoted patent is positioned normal to the radiation propagation direction. This position of the plates is not favorable for radiation attenuation, as explained above. Toepel invented a radiation shield composed of hinged plates. In Toepel's invention, the position of the panel, as represented by the angle between the panel plane and the direction of the incident radiation plays no role. In contrast, our invention essentially relies on the control of that angle. Short presented a radiation shield with variable attenuation that is essentially able to partly or completely interact with the radiation moreover that can change its structural properties at a microscopic scale in order to change its radiation attenuation. Short teaches a shield that is able to produce only intermediate levels of attenuation, between the attenuation provided when the slabs are perpendicular to the radiation propagation direction and zero attenuation. Therefore, Short's shield and shield adaptation method can not increase the attenuation over the level obtained when the slabs are perpendicular to the radiation direction. The significant distinction of the shield described in this invention compared to the state of the art is that it teaches a method to significantly improve the attenuation above the level achieved when the slabs are perpendicular to the radiation direction. The increase in attenuation, according to the present invention, is, however, obtained in general by a decrease of the volume of the protected space. In this example, the actuation system consists of hydraulic/pneumatic pumps (25), driven by motors (24), and connected through flexible tubes (26) to a set of pistons (18) such that each piston can be individually controlled by the control system (10). The digital control system (10) may be, in a non-limitative example, a microcontroller. The microcontroller is connected through power circuitry to the set of motors that drive the pumps. Each piston (18) is connected to an external frame (19) and to a joint (2) of the shield. The joints are alternately disposed, as to allow for the deformation of the shield structure. This example uses twice the number of pistons, pumps and motors required by the example in FIG. 1. FIG. 15 A illustrates the sketch of a shield with hydraulic or pneumatic actuators, each used to move two successive plates. The actuators are externally placed with respect to the shield. As each piston corresponds to two adjacent plates (1) of the shield, there is no need for an external frame to the shield. FIG. 15 B shows the sketch of a shield with hydraulic or pneumatic actuators, each used to move two successive plates. The actuators are internally placed with respect to the shield, in contrast to FIG. 3. The details are provided as examples, for the easy understanding of the main ideas in the description. The actual realization needs not follow any of these examples. The joints of the shield assembly may be driven, in a non-limitative example, by gears driven by electric motors. The electric motors (24) actuating the elements of the shield are fixed directly to one of the plates in each couple of successive plates connected by hinges (one motor on every second plate). The digital control system (e.g. microcontroller) controls the motors (24) through an appropriate high current driver. FIG. 14 shows a detailed view of a sensor assembly (9), including an OPAMP (operational amplifier) (22), the elementary sensor (23) and the signal conditioning (24). FIG. 15A shows the motor (24) driving the first wheel (27) of the gear. The second wheel (28) of the gear is connected to the axis (29) of the hinge. Such a gear mechanism can be used to rotate two successive plates. (FIG. 15A shows only one section of the hinge.) Skilled mechanical and electrical engineers can design, using current CAD tools, various joint elements, pneumatic, hydraulic, and electro-mechanical actuators, as well as driving and control circuitry. These elements are known to the art and are not patentable parts of the proposed system, although they are needed for the actual realization of some variants of the proposed system. Some of these elements can be purchased as commercially available parts. In another non-restrictive construction variant, the shield is made of an elastic material, such as rubber with an elevated content of radiation absorption material, elastic material that may be deformed and adapted in terms of shape according to the requirements of optimal protection. In contrast to Example 1, this variant does not need hinges, but needs means to fold the elastic material and to guide the folds according to a specified shape of the shield. Means to fold can be laces pulled by wheels/pulleys driven by electric motors. The anti-radiation shield also behaves adaptively in the case of two or several directional radiation sources. In that case, the angle formed by the successive plates, or the shape of the elastic shield—if the shield is made out of elastic material—is controlled depending on the directions and intensities of the two sources of radiation, aiming to maximize total absorption of the radiation coming from the two sources. I further disclose elements suitable for one or several realizations. In another non-limiting realization, at least some of the radiation sensors inside the protected space are worn by the protected personnel. In this case, the control information for the shield comes directly from the personnel and the shield orients such that it offers the best protection in those work areas. Indeed, it is known that for shields of irregular shapes, the level of ensured protection is not the same in all points of the protected space. Therefore, especially in the case in which people modify their position in time, optimal adaptation is achieved depending on the positions of the protected people. Information flow from the people-borne sensors to the control system may be realized either through radio, infrared, or other communication method. In another non-restrictive construction, the control system uses either only external sensors, case in which the system has to compute the level of radiation in the protected space, or uses only internal sensors, case in which the adaptation may be realized only depending on the information about the level of radiation in the protected space. In another non-limiting design, the radiation shield is formed out of a primary, non-adaptive shield supplemented by a system of directional—adaptive shields—which ensure protection only in a specified direction. The adaptive shield can be temporarily moved toward the direction from where high intensity radiation comes from. Thus, the assembly comprising a primary, non-adaptive, omni-directional, and a supplementary adaptive shield includes mobile elements that allow for the displacement of shielding elements with respect to the direction from where temporary strong radiation occurs, the said displacement being performed such as to maximize the absorption of the radiation. In another non-limiting design, the measuring system of internal/external radiation is supplemented with an alarm system triggered at the increase in radiation levels. In another non-restrictive construction, in which the internal sensors are not carried by the personnel, the radiation shield may feature a system of position sensors for automatic detection of the position of the protected persons, such that the computation of the position of the plates or slates composing the shield the related computation of the shape of the shield is aimed to optimal radiation dampening in the work area of those persons. The radiation shield is adaptive as it allows for the variation of the protected volume in order to ensure the radiation in the protected area below a maximum permitted value. Thus, in the case of an increase in incident flux, the shield can restrain the protected volume in order to ascertain the interior radiation flux under the specified “safe” value. In the event of a drop in external radiation flux, the shield can distend to allow for a larger protected volume. If the protected structure is cylindrical, in a non-limitative design, the shielding system may use a single internal/external sensor—or a pair of sensors—one internal and the other external—able to move on a helicoidal path, such as to cover the entire protected surface. In the case of radiation obliquely incident to the shield, the dampening effect of the shield may be reduced compared to the dampening for radiation of normal incidence. Therefore, for an obliquely incident radiation, the optimal shape of the shield is different than the optimal shape for normally incident radiation. In order to determine which one is the angle of incidence of the most intense radiation, the sensors (16) will be able to do a precession-type rotation (17). The optimal shield shape will be computed taking into account the radiation's angle of incidence. On the same principle, radiation protection clothes can be conceived. “Radiation shield”-clothes can be manufactured out of fabrics that contain radiation-absorbing materials and have shapes that can be modified through controlled folding/contraction in the more-in-need of protection areas, or through controlled distension in the less-in-need of protection areas. The less-in-need of protection areas are characterized by a smaller radiation input. As described, the clothes obtain a larger apparent thickness in the high radiation input areas. The extension/contraction may be realized, in a non-limitative design, by pulling straps/wires in the fabric. The straps/wires are operated by a control system in a similar way existing clothes are manipulated to form pleats and folds, or current ripplefold system or accordia-fold system draperies are used. In yet another version of realization of the shield, the plates or the elastic or textile material used to absorb the radiation may be realized of or covered in magnetic material, such as to confer them magnetic properties. The shield is coupled to a magnetic field generator, such that it is magnetized. By changing the position of the plates, the intensity of the magnetic field is increased in the vicinity of the plates and the charged particles constituting a component of the radiation will be at least partially deflected by the magnetic field. It is well known that strong solar activity can cause major disruptions in the electric distribution energy. The application of adaptive shielding for critical buildings such as power plants might be useful in preventing similar disruptions in the future. In a non-limitative design, the building's walls (3) may be mobile and formed out of articulated plates (1). The adaptive shield's control system must also take into account the Sun's relative movement to Earth's surface. Thus, the shield will have to continually adapt in order to provide the best attenuation in the Sun's direction. In all realizations, the radiation shield may be controlled according to an algorithm that minimizes the effect of primary or of total radiation on the people inside the protected space, taking into account the specific absorption coefficients of the human body and biological effects of radiation. In the description of the invention up to this point, only the primary radiation case has been dealt with. Here, we add the solution for the case when the secondary radiation is also important, because of the high-energy primary radiation that produces secondary radiation in the shield. In the case of potentially powerful secondary radiation, the shield is composed of at least two layers, one used to absorb the energetic particles/radiation, and the second used to absorb the less energetic particles/radiation generated as secondary-radiation, the first said layer being realized from a material including heavy atoms, while the second including lighter atoms. The shield can also be realized of a composite or mixed material to ensure appropriate absorption of both high and low energy particles. Radiation-absorbing materials are known to the art and do not constitute the object of this invention. FIG. 16 summarizes the principle of the invention and provide further examples of adaptation. FIG. 16 illustrates a shield with rectangular initial shape that improves the protection of the personnel (30) either by global rotation of the shield without change in shape, or by both global rotation and change of shape, moreover compares the method of adaptation of the initially rectangular shield with the method of adaptation of the shield shown in FIG. 1. The skilled reader will recognize the unity of the solution in all the variants. Indeed: i) All variants are based on a single major idea, namely that change of orientation of a (macro-, micro-, or nano-) shield may strongly modify the radiation absorption. The idea is applied to macroscopic plates, to macroscopic elastic absorbing materials, and to textiles and absorbent draperies. Moreover, it is applied to devise “active” principles for non-homogeneous anisotropic materials that can be changed to adapt to the incoming radiation, ensuring best shielding. ii) All the proposed embodiments, either macro- or micro-embodiments of the above idea serve the same practical purpose: reconfigurable radiation shields. The radiation shield has several advantages. Among others, it ensures a significantly increased protection, at the same mass of the shield and the same materials composing the shield, compared with static, rigid, non-adaptive shields. Moreover, the shield operates automatically and implicitly can offer an alarm to the personnel occupying the protected space. To protect the personnel, the shield allows the temporary reduction of the protected space, when the levels of incoming radiation impose this situation. Compared to a static shield of the same mass, the disclosed reconfigurable shield improves the ratio (protected volume)/(weight). The adaptive radiation shield can be industrially used in applications like space transport, in the medical domain, as well as in other terrestrial domains where intensity fluctuating radiation and variable direction radiation can be a hazard. The adaptive shield is technologically feasible with today means and with commercially available parts and materials. The precise design can be produced using existing CAD tools. In case of the adaptive shield variant based on ferro-fluids, it can be developed based on the current knowledge in the field, as reflected in the literature. Although only a few embodiments have been described in detail above, those skilled in the art can recognize that many variations from the described embodiments are possible without departing from the spirit of the invention. 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Manipulation of liquid droplets using amphiphilic, magnetic one-dimensional photonic crystal chaperones, Jason R. Dorvee, Austin M. Derfus, Sangeeta N. Bhatia, Michael J. Sailor, Published online: 7 Nov. 2004; Nature Materials, Advance Online Publication, www.nature.com/naturematerials
	abstract	A tool to slide a channel on a nuclear reactor fuel bundle assembly, the tool includes: a plate having a slot to receive a handle of the fuel bundle and a lower surface that engages an upper edge of the channel; at least one post extends up from the plate, and an arm is attached to a pivot on the post and includes a first end to receive a downward force and a second end adapted to engage the handle of the fuel bundle to apply an upward force to the handle and push down on the channel.
061343013	claims	1. A combing tool and collimator for use in connection with a computed tomography system, said collimator including a plurality of attenuating blades, each of said blades extending substantially parallel to an adjacent one of said blades, said combing tool comprising a handle and a plurality of substantially parallel teeth having cavities therebetween extending from said handle, said tool configured to verify alignment of said collimator blades. 2. A combing tool and collimator in accordance with claim 1 wherein said teeth are configured to be inserted between adjacent said attenuating blades. 3. A combing tool and collimator in accordance with claim 1 wherein each of said cavities is configured to receive at least one said attenuating blade. 4. A combing tool and collimator in accordance with claim 1 wherein said teeth each have a substantially different thickness. 5. A combing tool and collimator for use in connection with a computed tomography system, said collimator including a plurality of attenuating blades, each of said blades extending substantially parallel to an adjacent one of said blades, and said combing tool comprising means for verifying alignment of said collimator blades. 6. A combing tool and collimator for use in connection with a computed tomography system, said collimator including a plurality of attenuating blades, each of said blades extending substantially parallel to an adjacent one of said blades, and said combing tool comprising a plurality of substantially parallel teeth having cavities therebetween and configured to verify alignment of said collimator blades. 7. A combing tool and collimator in accordance with claim 6 wherein said teeth are configured to be inserted between adjacent said attenuating blades. 8. A combing tool and collimator in accordance with claim 6 wherein each of said cavities is configured to receive at least one said attenuating blade. 9. A combing tool and collimator in accordance with claim 6 wherein said teeth have a substantially similar thickness. 10. A method for ensuring that attenuating blades of a collimator are substantially parallel using a combing tool having a plurality of substantially parallel teeth having cavities therebetween, said method comprising the step of inserting the combing tool teeth between adjacent attenuating blades. 11. A method in accordance with claim 10 wherein each of the cavities is configured to receive at least one attenuating blade. 12. A method in accordance with claim 11 further comprising the step of brushing the blades. 13. A method in accordance with claim 10 further comprising the step of brushing the blades.
	abstract	A storage rack arrangement (10) for the storage of nuclear fuel elements in a storage pool includes at least two storage racks (1.1-1.3) which each contain a plurality of vertical channels (9) arranged next to one another for the reception of the fuel elements, with positioning elements (6) being provided at the storage racks at the bottom. The storage racks are connected to one another at the top and the storage rack arrangement (10) additionally includes one or more base plates (2.1-2.3) which are provided with positioning members (8) which fit with the positioning elements (6) of the storage racks (1.1-1.3) and which, together with the positioning elements, position the storage racks with respect to the base plate or base plates (2.1-2.3) to prevent a displacement of the storage racks on the base plate or plates.
	description	The present invention relates to a chemical decontamination method for decontaminating a decontamination object to which a radioactive insoluble substance (crud) is adhered in a nuclear power plant or the like. Examples of the method for chemically decontaminating a decontamination object to which crud is adhered include the methods described in PTLs 1 to 3. In PTL 1, a chemical decontamination method that includes a reductive dissolution step in which decontamination is performed using a reductive decontamination solution containing formic acid and oxalic acid and an oxidative dissolution step in which decontamination is performed using a decontamination solution containing an oxidizing agent is described. In PTL 2, a chemical decontamination method that includes a first step in which decontamination is performed using oxalic acid and a second step in which decontamination is performed using a reductive decontamination solution containing formic acid and oxalic acid is described. In PTL 3, a chemical decontamination method that includes a step in which decontamination is performed using a reductive decontamination solution containing formic acid and oxalic acid and a step in which metal ions contained in the decontamination solution are subsequently separated using a cation-exchange resin is described. PTL 1: JP 4131814 B PTL 2: JP 2009-109427 A PTL 3: JP 4083607 B In the decontamination of carbon steel, the amount of metal ions contained in a decontamination solution keeps increasing due to the corrosion of a base metal. Since the amount of iron ions that are to become dissolved in the decontamination solution is unpredictable, a large amount of cation-exchange resin needs to be used for purifying a decontamination waste solution. When oxalic acid is used as a decontamination agent, a coating film composed of iron oxalate is formed on the surface of carbon steel. This coating film may inhibit the decontamination effects. The iron oxalate coating film remains on the surface of the carbon steel. An object of the present invention is to provide a chemical decontamination method capable of purifying a decontamination waste solution with a small amount of cation-exchange resin and performing decontamination with efficiency. The chemical decontamination method according to the present invention comprises dissolution step in which a radioactive insoluble substance containing a metal oxide, the radioactive insoluble substance being adhered to a decontamination object including carbon steel, is dissolved in a decontamination solution and a metal-ion removal step in which the decontamination solution containing the metal ion, the decontamination solution being produced in the dissolution step, is brought into contact with a cation-exchange resin in order to remove the metal ion, the dissolution step including a reductive dissolution step conducted using a decontamination solution containing formic acid, ascorbic acid and/or erythorbic acid (hereinafter, referred to as “ascorbic acid, etc.”), and a corrosion inhibitor. In one aspect of the present invention, the decontamination object includes carbon steel and stainless steel, and the dissolution step includes an oxidative dissolution step conducted using a decontamination solution containing permanganic acid and/or a permanganic acid salt (hereinafter, referred to as “permanganic acid (salt)”) at a concentration of 100 to 2,000 mg/L, a reductive decomposition step in which a reducing agent is added to the decontamination solution treated in the oxidative dissolution step in order to perform reductive decomposition of the permanganic acid (salt), and the reductive dissolution step conducted subsequent to the reductive decomposition step. In one aspect of the present invention, in the reductive decomposition step, ascorbic acid, etc. is added to the decontamination solution in an amount 1.0 to 2.0 times the amount equivalent to the permanganic acid (salt) in order to perform the reductive decomposition of the permanganic acid (salt). In one aspect of the present invention, in the reductive dissolution step, the metal oxide is dissolved in a decontamination solution containing formic acid at a concentration of 1,000 to 10,000 mg/L, ascorbic acid, etc. at a concentration of 400 to 4,000 mg/L, and a corrosion inhibitor at a concentration of 100 to 500 mg/L. In one aspect of the present invention, the metal-ion removal step includes a first cation-exchange treatment step in which the decontamination solution containing the metal ion, the decontamination solution being produced in the reductive dissolution step, is passed through a cation-exchange resin column in order to produce first cation-exchange treatment water containing an Fe ion at a concentration of 300 mg/L or less. In one aspect of the present invention, subsequent to the first cation-exchange treatment step, a formic acid oxidative decomposition step in which a corrosion inhibitor is added to the first cation-exchange treatment water at a concentration of 200 to 300 mg/L and hydrogen peroxide is subsequently added to the first cation-exchange treatment water in an amount 1 to 3 times the amount equivalent to the formic acid in order to decompose the formic acid using the Fe ion as a catalyst is conducted. In one aspect of the present invention, the metal-ion removal step includes a second cation-exchange treatment step in which water treated in the formic acid oxidative decomposition step is irradiated with ultraviolet radiation and subsequently passed through a cation-exchange resin column in order to remove the metal ion. In one aspect of the present invention, an ascorbic acid, etc. oxidative decomposition step in which a corrosion inhibitor is added to water treated in the second cation-exchange treatment step at a concentration of 200 to 300 mg/L, hydrogen peroxide is subsequently added to the treated water, and the treated water is then irradiated with ultraviolet radiation in order to perform oxidative decomposition of the ascorbic acid, etc. is conducted. In one aspect of the present invention, water treated in the ascorbic acid, etc. oxidative decomposition step is passed through a mixed-bed resin column in order to produce treated water having an electric conductivity of 2 μS/cm or less. In the chemical decontamination method according to the present invention, a corrosion inhibitor is used for reducing the corrosion of carbon steel. This limits an increase in the amount of metal ions contained in the decontamination solution due to the corrosion and results in reductions in the amount of cation-exchange resin used for purifying the metal ion-containing decontamination solution, that is, a decontamination waste solution, and the amount of wastes. The decontamination solution used in the present invention contains formic acid, ascorbic acid, etc., and a corrosion inhibitor. This prevents formation of a coating film composed of iron oxalate or the like on the surface of carbon steel and increases the decontamination effects. Furthermore, the dissolving power of the decontamination solution is increased, which results in great decontamination efficiency. In the chemical decontamination method according to the present invention, the decontamination object includes carbon steel to which a radioactive insoluble substance (crud) containing a metal oxide is adhered. Examples thereof include pipes, various devices, and structural members and soon included in radiation-handling facilities, such as a nuclear power plant. Examples of the decontamination object including carbon steel include a decontamination object composed only of carbon steel and a decontamination object composed of carbon steel and stainless steel. The chemical decontamination method according to the present invention is divided into the following two types of decontamination steps depending on the type of the decontamination object. (1) A Case where the Decontamination Object is Composed of Carbon Steel and Stainless Steel [Oxidative dissolution step]→[Reductive decomposition step]→[Reductive dissolution step]→[First cation-exchange treatment step]→[Formic acid oxidative decomposition step]→[Second cation-exchange treatment step]→[Ascorbic acid, etc. oxidative decomposition step]→[Final Purifying Step using Mixed-bed] (2) A case where the decontamination object is composed only of carbon steel [Reductive dissolution step]→[First cation-exchange treatment step]→[Formic acid oxidative decomposition step]→[Second cation-exchange treatment step]→[Ascorbic acid, etc. oxidative decomposition step]→[Final purifying step using mixed-bed] Although the oxidative dissolution step and the reductive decomposition step may be conducted prior to the reductive dissolution step even in the case where the decontamination object is composed only of carbon steel as in the case where the decontamination object is composed of carbon steel and stainless steel, it does not increase the advantageous effects. Therefore, in the case where the decontamination object is composed only of carbon steel, it is preferable to start with the reductive dissolution step. For example, when the inner surface of a pipe or the like is decontaminated in the above-mentioned oxidative dissolution step or reductive dissolution step, it is preferable to pass a decontamination solution containing an oxidizing agent or reducing agent first through the pipe in a circulatory manner. Specifically, it is preferable to store the decontamination solution in a tank and pass the decontamination solution through the pipe or the like in a circulatory manner with a circulation pump. The reductive decomposition step is preferably conducted while the circulation of the decontamination solution is continued. Details of each of the above steps are described below. [Oxidative Dissolution Step] The decontamination solution used in the oxidative dissolution step preferably contains, as an oxidizing agent, permanganic acid and/or a permanganic acid salt (hereinafter, referred to as “permanganic acid (salt)”) at a concentration of 100 to 2,000 mg/L or, specifically, 200 to 500 mg/L. Common examples of a permanganic acid salt include, but are not limited to, potassium permanganate. The oxidizing agent-containing decontamination solution is preferably heated at 50° C. to 100° C. or, specifically, 80° C. to 90° C. and passed through a pipe in a circulatory manner for about 3 to 6 hours. The circulation of the oxidizing agent-containing decontamination solution causes oxidative dissolution of chromium included in the metal oxide contained in the crud. [Reductive Decomposition Step] Subsequent to the above-mentioned oxidative dissolution step, while the circulation of the above-mentioned oxidizing agent-containing decontamination solution is continued, a reducing agent is added to the oxidizing agent-containing decontamination solution in order to perform reductive decomposition of residual permanganic acid (salt). Ascorbic acid, etc. is suitable and ascorbic acid is particularly suitable as a reducing agent used for reducing the permanganic acid (salt). The amount of the ascorbic acid, etc. used is preferably 1.0 to 2.0 times and is particularly preferably 1.0 to 1.5 times the amount equivalent to the permanganic acid (salt) contained in the decontamination solution. The reductive decomposition of potassium permanganate, which is an example of the permanganic acid (salt), by ascorbic acid is represented by the following equation:2 KMnO4+3 C6H8O6→2 MnO2+2 KOH+2 H2O+3 C6H6O6 The temperature of the decontamination solution at the time when the ascorbic acid, etc. is added to the oxidizing agent-containing decontamination solution is preferably 50° C. to 100° C. and is particularly preferably 80° C. to 90° C. While the decomposition of a permanganic acid (salt) by oxalic acid generates a carbonic acid gas, the decomposition of a permanganic acid (salt) by ascorbic acid, etc. does not generate a gas and eliminates the risk of cavitation in a circulation pump. [Reductive Dissolution Step] Subsequent to the above-mentioned step of reductive decomposition of the permanganic acid (salt), a reductive dissolution step in which, while the water treated by the reduction treatment is passed through a pipe or the like in a circulatory manner, formic acid, ascorbic acid, etc., and a corrosion inhibitor are added to the water treated by the reduction treatment in order to dissolve metal oxides with a decontamination solution containing formic acid, ascorbic acid, etc., and a corrosion inhibitor is conducted. As described above, in the case where the decontamination object is composed only of carbon steel, the reductive dissolution step is conducted by passing a reducing agent-containing decontamination solution containing predetermined amounts of formic acid, ascorbic acid, etc., and a corrosion inhibitor through a pipe or the like in a circulatory manner. The ascorbic acid, etc. is particularly preferably ascorbic acid. The corrosion inhibitor is preferably an organic corrosion inhibitor. For example, a corrosion inhibitor containing an imidazoline quaternary ammonium salt (imidazoline surfactant) and thiourea and/or alkylthiourea (e.g., a corrosion inhibitor containing 1 to 5 weight % thiourea and/or 1 to 5 weight % alkylthiourea and 1 to 5 weight % imidazoline quaternary ammonium salt (imidazoline surfactant)) is preferable. The contents of the above components in the decontamination solution or the amounts of the above components added to the decontamination solution are as follows. Formic acid: 1,000 to 10,000 mg/L and, specifically, 2,500 to 5,000 mg/L Ascorbic acid, etc.: 400 to 4,000 mg/L and, specifically, 1,000 to 2,000 mg/L Corrosion inhibitor: 100 to 500 mg/L and, specifically, 200 to 300 mg/L In this step, the water temperature is preferably 50° C. to 100° C. and is particularly preferably 80° C. to 90° C., and the amount of time during which the circulation of the decontamination solution is preferably about 6 to 24 hours. This step causes the metal oxides contained in the crud adhered to the decontamination object to be reduced and removed by dissolving. [First Cation-Exchange Treatment Step] The metal ion-containing decontamination solution produced in the above-mentioned reductive dissolution step is treated by cation exchange in order to cause Fe ions to be adsorbed to a cation-exchange resin and removed. In this first cation-exchange treatment step, the cation-exchange treatment is performed such that the concentration of Fe ions is preferably reduced to about 300 mg/L or less and is particularly preferably reduced to about 200 mg/L or less. This is because, when Fe ions remain in the water treated by the first cation-exchange, the residual Fe ions can be used as a catalyst in the subsequent step, that is, the formic acid oxidative decomposition step. In the case where the concentration of Fe ions is less than 100 mg/L in the first cation-exchange treatment step, it is preferable to add Fe ions (e.g., an Fe salt) to the water treated by the first cation-exchange before the subsequent step is started. The first cation-exchange treatment step is preferably conducted by passing the water treated in the reductive dissolution step having a liquid temperature of 50° C. to 90° C. or, specifically, 80° C. to 90° C. through a cation-exchange resin column at an SV of 20 to 50 hr−1. [Formic Acid Oxidative Decomposition Step] Subsequent to the above-mentioned first cation-exchange treatment step, oxidative decomposition of the formic acid contained in the water treated by the first cation-exchange is performed. Since the corrosion inhibitor is also removed in the first cation-exchange treatment step by being adsorbed to the cation-exchange resin, it is preferable to again add the same corrosion inhibitor as that used above to the water treated by the first cation-exchange at a concentration of about 200 to 300 mg/L in the formic acid oxidative decomposition step in order to suppress corrosion. Subsequently, hydrogen peroxide is added to the water treated by the first cation-exchange in an amount 1 to 3 times or, preferably, 1 to 2 times the amount equivalent to the formic acid in order to perform oxidative decomposition of the formic acid using Fe ions as a catalyst, which is represented by the following equation:HCOOH+H2O2→2 H2O+CO2 [Second Cation-Exchange Treatment Step] After it has been confirmed, by the Fenton method or the like, that the hydrogen peroxide contained in the water treated in the above-mentioned formic acid oxidative decomposition step has been completely decomposed (e.g., the concentration of the residual hydrogen peroxide is 1.0 mg/L or less) and, preferably, the treated water has been passed through an UV column equipped with a low-pressure mercury lamp and irradiated with UV (ultraviolet radiation) in order to reduce an Fe3+ ion to an Fe2+ ion, the treated water is passed through a cation-exchange resin column in order to remove metal ions (in particular, Fe ions) such that the concentration of the metal ions is reduced to preferably less than 1 mg/L. In this step, the water temperature is preferably 90° C. or less, and the SV is preferably about 20 to 50 hr−1.[Ascorbic Acid, etc. Oxidative Decomposition Step] Subsequent to the above-mentioned second cation-exchange treatment step, oxidative decomposition of the ascorbic acid, etc. contained in the water treated by the second cation-exchange is performed. Since the corrosion inhibitor is also removed by adsorption in the second cation-exchange treatment step, the same corrosion inhibitor as that used above is added to the water treated by the second cation-exchange at a concentration of about 200 to 300 mg/L in this ascorbic acid, etc. oxidative decomposition step. Subsequently, hydrogen peroxide is added to the water treated by the second cation-exchange in an amount 0.8 to 2.0 times or, for example, in an amount substantially equal to the amount equivalent to the ascorbic acid, etc. and the treated water is irradiated with UV in order to perform oxidative decomposition of the ascorbic acid, etc. into water and a carbon dioxide gas. This reaction is represented by the following equation:C6H8O6+10 H2O2→6 CO2+14 H2O In this step, the water temperature is preferably 90° C. or less. The treated water produced by the above treatment has a TOC concentration of 2 mg/L or less.[Reuse of Treated Water] The treated water may be fed to the mixed-bed final purifying step described below or may be reused for preparing a decontamination solution. It is preferable to fed the water treated in the ascorbic acid, etc. oxidative decomposition step to the following mixed-bed final purifying step after using the treated water in the cycles of the oxidative dissolution step to the ascorbic acid, etc. oxidative decomposition step (when the decontamination object is composed of carbon steel and stainless steel) or the reductive dissolution step to the ascorbic acid, etc. oxidative decomposition step (when the decontamination object is composed only of carbon steel) about 2 to 4 times. [Mixed-Bed Final Purifying Step] After it has been confirmed, by the Fenton method or the like, that hydrogen peroxide does not remain in the water treated in the above-mentioned ascorbic acid, etc. oxidative decomposition step (e.g., the concentration of hydrogen peroxide is 1.0 mg/L or less), the treated water is passed through a mixed-bed resin column preferably at an SV of 20 to 50 hr−1 in order to remove cations and anions and to produce final treated water having an electric conductivity of 2 μS/cm or less. A system that included carbon steel pipes (STPG370) having a length of 10 m and an inside diameter of 150 A and stainless steel pipes (SUS304) having a system capacity of 800 L and an inside diameter of 25 A was subjected to the decontamination treatment in accordance with the method according to the present invention. The corrosion inhibitor used was “IBIT 30AR” produced by Asahi Chemical Co., Ltd. Specifically, the following treatment was performed. First, as an oxidizing agent-containing decontamination solution, 0.5 m3 of a 300 mg/L potassium permanganate solution having a water temperature of 90° C. was prepared. The solution was stored in a tank and passed through the pipes in a circulatory manner at 2 m3/hr for 4 hours with a circulation pump (oxidative dissolution step). While the circulation of the decontamination solution was continued, 1 equivalent of ascorbic acid (ascorbic acid: 502 mg/L relative to potassium permanganate: 300 mg/L) was added to the decontamination solution in order to perform reductive decomposition of the potassium permanganate (reductive decomposition step). To the water treated by the reductive decomposition, formic acid: 3,500 mg/L, ascorbic acid: 1,500 mg/L, and corrosion inhibitor: 200 mg/L were added. Subsequently, the treated water was passed through the pipes in a circulatory manner at 90° C. and 2 m3/hr for 6 hours in order to dissolve metal oxides (reductive dissolution step). The decontamination waste solution (90° C.) discharged in the reductive dissolution step was passed through a cation-exchange resin column at an SV of 30 hr−1 in order to remove Fe ions by adsorption until the Fe ion concentration was reduced to 200 mg/L (first cation-exchange treatment step). A corrosion inhibitor was added to the water treated by the first cation-exchange at a concentration of 200 mg/L. Subsequently, hydrogen peroxide was added to the treated water at a concentration of 5250 mg/L (in an amount 2 times the amount equivalent to the formic acid) in order to decompose the formic acid using the Fe ions remaining in the water as a catalyst (formic acid oxidative decomposition step). After it had been confirmed that the concentration of the hydrogen peroxide remaining in the water treated by the oxidative decomposition of formic acid was 1.0 mg/L or less, the treated water was passed through an UV column and irradiated with UV. Subsequently, the treated water was passed through a cation-exchange resin column at an SV of 30 hr−1 in order to reduce the concentration of Fe ions to about 1 mg/L (second cation-exchange treatment step). In this step, the heater was turned off and the water temperature naturally decreased. A corrosion inhibitor was added to the water treated by the second cation-exchange at a concentration of 200 mg/L. Subsequently, hydrogen peroxide was added to the treated water at a concentration of 175 mg/L (in an amount 1 time the amount equivalent to the ascorbic acid). The treated water was then passed through an UV column and irradiated with UV in order to decompose the ascorbic acid (ascorbic acid, etc. oxidative decomposition step). The treated water had a TOC concentration of 2 mg/L. After the sequence of the above-mentioned steps had been repeated 3 times, it was confirmed by the Fenton method that the concentration of the hydrogen peroxide contained in the water treated by the oxidative decomposition of ascorbic acid had been reduced to 1.0 mg/L or less. Subsequently, the treated water was passed through a mixed-bed resin column at an SV of 30 hr−1 (mixed-bed final purifying step). As a result, treated water having an electric conductivity of 2 μS/cm was produced. Although the present invention has been described in detail with reference to particular embodiments, it is apparent to a person skilled in the art that various modifications can be made therein without departing from the spirit and scope of the present invention. The present application is based on Japanese Patent Application No. 2017-046403 filed on Mar. 10, 2017, which is incorporated herein by reference in its entirety.
	abstract	A phase contrast electron microscope has an objective (8) with a back focal plane (10), a first diffraction lens (11), which images the back focal plane (10) of the objective (8) magnified into a diffraction intermediate image plane, a second diffraction lens (15) whose principal plane is mounted in the proximity of the diffraction intermediate image plane and a phase-shifting element (16) which is mounted in or in the proximity of the diffraction intermediate image plane. Also, a phase contrast electron microscope has an objective (8) having a back focal plane (10), a first diffraction lens (11), a first phase-shifting element and a second phase-shifting element which is mounted in or in the proximity of the diffraction intermediate image plane. The first diffraction lens (11) images the back focal plane of the objective magnified into a diffraction intermediate image plane and the first phase-shifting element is mounted in the back focal plane (10) of the objective (8). With the magnified imaging of the diffraction plane by the diffraction lens, the dimensional requirements imposed on the phase plate having the phase-shifting element are reduced.
040175677	summary	The invention is directed to the process of producing block fuel elements for gas cooled high temperature fuel reactors. The known block fuel elements are, for example, hexagonal prisms made of graphite and having a width over the flats of the hexagon of 360 mm and a height of 793 mm., see Docket 50267 -14(November 1969) page 3.4-1 Fort St. Vrain Nuclear Generating Station Final Safety Analysis Report. In the inside of the prism there are found in hexagonal arrangement about 320 bore holes running parallel to the longitudinal axis. Two thirds of these bore holes serve to receive the fuel containing cylinders and the remainder serves as channels for helium-cooling gas. The fuel cylinder consists of a carbon matrix in which the fuel and fertile material is embedded in the form of coated particles. The coated particles are spherical heavy metal oxide or carbide cores of several hundred microns diameter which preferably are coated several times with pyrolytically deposited carbon. In general as fuels there are used U 235, U 233 and fissionable plutonium isotopes. As fertile material there is employed thorium or uranium 238. The coating has the function of largely retaining the fission products formed in the particles. The total volume of the block fuel elements amounts to 89 liters. This is distributed as 18.5 volume percent cooling channels, 23.5 volume % fuel bore holes and 58 volume percent block graphite, which forms the fuel element structure. Furthermore, there are known, for example, fuel elements having a width over the flats of hexagon of 383 mm. and a height of 1050 mm. (see D.F.I. Bishop. Factors Affecting the Costs of Fabricating HTR Fuel. Dragon Project Fuel Symposium Paper, October 1969). The fuel element prism has only 18 hexagonally arranged fuel holes of 63 - 70 mm. diameter in which 36 graphite containers (two per bore hole) stand one on top of the other. Between the bore holes and graphite containers there is found a 5 mm. Wide annular gap for helium gas. The graphite container is a 500 mm. long tube in which 10 annular fuel containing compacts are piled up one on the other. The compacts consist of a graphite matrix with pressed in coated fuel particles. Of the 133liters of total fuel element volume 18.5 volume % is cooling channels for helium gas, 11 volume percent is fuel compacts and 70.5 volume percent is the structural graphite. The classification clearly shows that only 23.5 or 11 percent of the fuel element volume can be filled with fuel. In contrast the structural graphite requires the largest volume portion, i.e. 58 or 70.5 percent. In order to better utilize the fuel element volume it has been proposed to employ molded block fuel elements, Hrovat, U.S. Ser. No. 3284 filed Jan. 16, 1970, corresponding to German application P 19 02 994.8 filed Jan. 22, 1969. In contrast to the previously named types of fuel elements the molded block fuel element is a compact prism provided with cooling channels, which consist of only a homogeneous graphite matrix and coated fuel particles. It is essential that the graphite matrix in which the coated particles are impressed simultaneously form the fuel element structure. Consequently in relation to the portion of fuel particles, a far greater fuel volume is available. Besides there is eliminated the gap acting as heat flow barrier between the fuel zone and structural graphite. Additionally, at unchanged fuel element loading, the power density in the fuel zone is strongly reduced, the heat output considerably improved and correspondingly the temperature gradient and consequently the thermal and radiation induced stress greatly reduced. Moreover, the lower stress and the improved efficiency of the prism volume permits a several fold increase of the fuel and fertile material content in the fuel element, whereby the construction of the cooling channels (volume and surface area) can be adjusted without limitation of the sides of the fuel elements to the optimum cooling conditions. The increase fuel load considerably reduces the cost of producing the fuel element and simultaneously leads to higher powder density in the reactor core and also a lower capital cost, see R.C. Dahlberg "Comparison of HTGR Fuel Cycles for Large Reactors", Oak Ridge --Symposium April 1970, Paper No. 130, Session No. VI. The possibility of laying out the cooling channels without limitation reduces the helium pressure drop in the reactor core and accordingly the necessary pumping power for the helium cycle, which again reduces the cost of the generation of current. Besides the graphite matrix serves as moderator, heat conductor, secondary barrier for the fission products and protects the coated particles against a damaging corrosion by impurities which are present as traces in the helium cooling gas. A series of requirements are placed on the graphite matrix. 1. Good irradiation behavior up to temperatures of 1400.degree. C and to neutron exposure of about 7 .times. 10.sup.21 neutrons/cm.sup.2 (E>o,1MeV). This requirement assumes an as much as possible high crystallinity of the isotropic graphite matrix. 2. Good thermal conductivity and an as low as possible coefficient of thermal expansion in order that entry of inadmissible thermal stresses in the block fuel element be avoided. 3. Good strength properties. 4. Good corrosion resistance Furthermore, in the production there is required a non destructive consolidation of the coated fuel particles into the graphite matrix. The present invention avoids the technological difficulties of the known processes and permits the production of a block fuel element of any size and shape satisfying all requirements. According to the invention there is first produced from molding powder as shown in example 1 by molding spheres in rubber molds at room temperature and at 3000 kg/cm.sup.2 and comminuting these spheres an isotropic graphite granulate of high density having a definite porosity. The molding powder for the production of granulates consists of a mixture of natural graphite and binder resin, synthetic graphite and binder resin, or a mixture of both types of graphite powder with binder resin. When a mixture of natural and synthetic graphite are employed, they can be used in any proportions, e.g. 1 to 99 percent of either by weight. The isotropic graphite granulate produced in the first step has an apparent density between 1.5 g/cm.sup.3 and 1.85 g/cm.sup.3 or as shown in example 1 even 1.9 g/cm.sup.3 and a porosity of 25 to 7.5 percent by volume. The molding pressure in the first step as shown in example 1 can be 3 t/cm.sup.2 (i.e., 3 metric tons/cm.sup.2). The temperature in the first step can be room temperature. The binder resin employed, for example, can be phenolformaldehyde, with a softening point of about 100.degree. C but phenolformaldehyde resins with other softening temperatures between 60.degree. and 120.degree. C or with addition of curing agents as for example hexamethylene tetramine or other formaldehyde resins for example on xylol or cresol base or furfurylalcohol resions can be used. The binder resin can be used in an amount of 10 to 30 percent of the graphite by weight. For the production of the isotropic granulate according to the invention in the first step, a fine graphite powder, e.g. about 20 microns in diameter, having a high crystallinity, is molded at high pressure with a binding agent additive, preferably phenol-formaldehyde resin, in a rubber mold to isotropic spheres. Subsequently the spheres are ground to granules having an average grain diameter of about 1 mm. The degree of fineness of the starting graphite powder is so chosen that on the average each granulate grain consists of several hundred thousand or even about 1,000,000 isotropically arranged graphite particles. For the production of the molding powder any graphite, independent of particle form is suited, for example, natural graphite powder, synthetic graphite powder or a mixture of the two. In another step the coated fuel particles in a rotating drum are overcoated with a molding powder of the same composition according to a kind of dragee process. As shown in example 2 to prepare fuel elements with a free zone in a second molding step the isotropic granulate is preliminarily molded to a block. The molding pressure in this step can be 30 kg/cm.sup.2, the temperature about 70.degree. C. The cooling channels can be bored out of the block either after the molding step or can be molded simultaneously with the molding of the block fuel element. As coated fuel particles there can be employed oxides or carbides of U 235, U 233 and fissionable plutonium isotropes a fuel materials in mixture with U 238 and/or Th 232 as fertile materials coated with multiple layers of pyrolytic carbon prepared in conventional manner. Conventional intermediate layers for example of SiC, ZrC or NbC can also be present in the coated fuel particles. The intermediate layers can be emitted.
046559914	summary	The present invention relates in general to nuclear fuel assemblies, and more particularly to apparatus for detecting the absence of helical springs on the shanks of fuel rod end plugs. BACKGROUND OF THE INVENTION In certain types of nuclear reactors, the nuclear fuel is contained in fuel rods. The fuel rods are grouped in fuel bundles, within which the fuel rods are equidistantly positioned from each other in a spaced array. The array itself is supported between an upper and a lower tie plate. A number of these fuel bundles are combined to form the nuclear fuel assembly. An arrangement of the type described is shown in U.S. Pat. No. 4,022,661, which is assigned to the assignee of the present invention. As shown, each fuel rod is resiliently supported between the tie plates by virtue of helical springs surrounding the elongated, reduced-diameter shanks of the upper end plugs of the fuel rods. This arrangement allows longitudinal expansion of the individual fuel rods. It also insures that the fuel rods are firmly seated in the lower tie plate to dampen vibration as pressurized liquid coolant flows upward through the fuel bundle to remove heat from the fuel rods. Typically, the lowest coil of each helical spring is of reduced diameter to provide a friction fit on the end plug shank. This inhibits "pop off" of the springs when the upper tie plate is removed. Further, it inhibits the spring from falling off during manipulation of a fuel rod outside the array. Not withstanding these precautions, springs are occasionally lost from the shanks of the end plugs. Poor visibility and other factors may prevent such a condition from being discovered before the upper tie plate is replaced or first installed. Once the fuel bundle is assembled, the upper tie plate obstructs the view of an observer, particularly with respect to those springs which are mounted on end plugs located near the center of the assembly. Thus, any visual inspection for the presence of these springs is precluded without removing the upper tie plate. Since the act of removing the tie plate may itself cause springs to be lost, as well as being a cumbersome and time-consuming procedure, there currently exists no satisfactory way for reliably detecting the absence of helical springs on the shanks of fuel rod end plugs in the assembled fuel bundle. OBJECTS OF THE INVENTION It is a principal object of the present invention to provide new and improved apparatus for detecting the absence of springs on the shanks of fuel rod end plugs, which is not subject to the foregoing disadvantages. Another object of the present invention is to provide a new and improved probe which permits ready and quick inspection of the springs on fuel rods located in an area of a fuel assembly that is inaccessible and blocked to visual inspection. An additional object of the present invention is to provide a new and improved probe which permits the positive detection of springs that are missing from the shanks of the fuel rod end plugs of a fuel assembly, without the necessity of removing parts from the latter. A further object of the present invention is to provide a new and improved probe which positively indicates the location within the fuel bundle of the fuel rod that is missing a spring. Still another object of the present invention is to provide a new and improved probe which locks in place when the absence of a spring is detected and which requires corrective action to be taken before the probe can be withdrawn from the fuel assembly. Yet another object of the present invention is to provide a new and improved probe for detecting the absence of springs on the shanks of fuel rod end plugs which is simple in construction and inexpensive to manufacture. SUMMARY OF THE INVENTION In accordance with the present invention, a probe is provided which comprises an elongate arm having at least one spring-engaging pawl resiliently biased outward from the shaft. When the probe is inserted between two rows of end plugs of the array, or withdrawn, contact with the springs that are present on the end plugs prevents the pawl from assuming its fully extended position urged by the applied resilient bias. If, however, a spring is missing from the shank of an end plug in the array, the pawl is allowed to move outward relative to the arm so as to become lodged between the springless end plug and its immediate neighbor. This action prevents the subsequent withdrawal of the probe from the fuel assembly and requires that the upper tie plate of the fuel assembly be removed. The position of the probe then indicates to the operator where a new spring must be placed on an end plug. The foregoing and other objects of the present invention, together with the features and advantages thereof, will become apparent from the following detailed specification when read with the accompanying drawings in which applicable reference numerals have been carried forward.
	claims	1. A method of three-dimensional image reconstruction for reconstructing a three-dimensional image of a specimen based on TEM (transmission electron microscope) images by tilting the specimen at plural tilt angles and obtaining the TEM images at these tilt angles, wherein(a) a positive focal point position of an objective lens incorporated in a transmission electron microscope is detected at each of the tilt angles of the specimen,(b) a focal point position of the objective lens is set to plural positions which are shifted from said positive focal point position by amounts of defocus Δf1, . . . , Δfn, respectively, at each of the tilt angles of the specimen and a TEM image is obtained at each of the set focal point positions,(c) a single optimum TEM image is selected at each of the tilt angles of the specimen from the TEM images obtained by the steps (a) and (b) above, and(d) a three-dimensional image of the specimen is reconstructed based on the selected TEM images. 2. A method of three-dimensional image reconstruction as set forth in claim 1, wherein said amount of defocus Δf1 is previously found by performing the steps of:setting the tilt angle of the specimen to an arbitrary angle θ1;detecting the positive focal point position f, of the objective lens at the set tilt angle θ1 of the specimen; andvarying an excitation current flowing through the objective lens such that an optimum TEM image is obtained and finding the amount of defocus Δf1 from the difference between the focal point position of the objective lens occurring at this time and said positive focal point position f1,wherein amounts of defocus other than Δf1 are previously found in the same way as Δf1. 3. A transmission electron microscope for reconstructing a three-dimensional image of a specimen by tilting the specimen at plural tilt angles, obtaining a TEM image at each of the tilt angles, and reconstructing the three-dimensional image based on the obtained TEM images, said transmission electron microscope comprising:defocus amount storage means for storing plural amounts of defocus Δf1, . . . , Δfn;positive focal point position detection means for detecting a positive focal point position of an objective lens at each of said tilt angles of the specimen;focal point position-setting means for setting a focal point position of the objective lens to positions shifted from the positive focal point position detected by said positive focal point position detection means by said amounts of defocus Δf1, . . . , Δfn, at each of said tilt angles of the specimen;an image memory for storing TEM images obtained at the focal points set by said focal point position-setting means in a corresponding manner to the respective tilt angles of the specimens;display means for displaying the TEM images stored in the image memory;image selection means for selecting one TEM image from the TEM images displayed on the display means at each of the tilt angles of the specimen; andthree-dimensional image reconstruction means for reconstructing a three-dimensional image of the specimen based on the TEM images selected by said image selection means.
	description	This application is a continuation of International Application No. PCT/EP2011/073051, filed Dec. 16, 2011, which claims the benefit of European Patent Application No. 10 197 257.8 filed Dec. 29, 2010, which are hereby incorporated by reference. The invention relates to a multi-leaf collimator, preferably for controlling a shape of a high-energy radiation beam emanating from a radiation source and propagating in a direction of propagation. In a preferred aspect, the invention relates to a multi-leaf collimator with leaf drives, with two sets of displaceable leaves arranged side by side facing each other in order to impress a high-energy beam with the shape of an irregularly formed treatment object by enabling each of the leaves to assume a position oriented along the shape of the treatment object by means of a leaf drive, with the leaf drives being designed in such a way that the each of the leaves is each equipped with a gear rod-like drive engagement in the direction of the displacement. As known in the art, the term “gear-rod-like drive engagement” can also be referenced by the English term “rack” or “rack gear”. The treatment devices used today in oncological radiation therapy are equipped with collimators that delimit high-energy beams, in most cases high energy radiation of a linear accelerator, in such a way that the beams have exactly the same shape as the treatment object. Since such radiation, e.g. of a tumor, occurs from various directions, it is possible to achieve a great irradiation intensity of the tumor and, at the same time, to stress the surrounding tissue only to a limited extent. The leaves of the multi-leaf collimator may also be called “shutter blades” or “lamellae”. The multi-leaf collimators may also be called contour collimators since due to the positioning of the leaves, contours of treatment objects, for example tumors, can be recreated for each beam application, each of which occurs from a certain solid angle. This is important in order to protect the adjacent healthy tissue to the greatest extent possible. In the case of critical tissue such as nerves, this is particularly necessary in order to preserve their functional capability. A multi-leaf collimator of the kind mentioned at the beginning has been known, for example, from EP 0 387 921 A2. Since in the case of such multi-leaf collimators, each leaf must be moved into a certain position, in most cases a drive must be assigned to each leaf. In the case of the aforementioned publication, not every leaf is assigned a motor, which is why the leaves are arranged in series by means of drive couplings and locking devices. However, it has also been known to assign an electric motor to each leaf that positions the leaves via a pinion and a gear rod-like drive engagement. However, the more precisely the shape of the treatment object, e.g. of a tumor, is to be recreated, the more and thinner leaves will be required. This means that a large number of electric motors and drive transmissions to the leaves must be housed in an extremely small space. In addition, these drives must be arranged in one area in such a way that they will be located within an irradiation head containing the radiations source and the collimator in an area in which structural space is available. Since for an irradiation, the irradiation head usually must be moved into various solid angles relative to the target volume, e.g. the tumor, it is desirable to design such a collimator as compact and lightweight as possible. In this way, a gantry or a robot arm that move the irradiation head into these solid angle positions can also be constructed with less weight, thereby making them faster movable into various positions and more mobile. The invention is therefore based on the objective of designing a multi-leaf collimator of the kind mentioned at the beginning in such a way that the leaf drives will be constructed as compact and lightweight as possible and attached to the collimator in such a way that they will be located in an available structural space of an irradiation head. This is achieved in accordance with the invention by the subject-matter disclosed in the independent claims. Preferred embodiments which may be realized and isolated way or in combination with other preferred embodiments are disclosed herein. In a first aspect of the present invention, a multi-leaf collimator is disclosed, with leaf drives, with two sets of displaceable leaves arranged side by side of each other and facing each other in order to impress a high-energy beam with the shape of an irregularly formed treatment object by enabling each of the leaves to assume a position oriented along the shape of the treatment object by means of the leaf drives. The leaf drives are designed in such a way that the leaves are each equipped with a gear rod-like drive engagement in a direction of the displacement, wherein a pivotable leaf-side gear segment located, together with a motor-side gear segment on a segment disk, engages with the gear rod-like drive engagement, with a pinion drivable by a motor engaging with the motor-side gear segment; wherein the segment disks are arranged side by side for each set of leaves as a package on one axis; and wherein the motor-side gear segments of two segment disks located next to each other are staggered in such a way that they will not abut each other. Preferably, the pinions are wider than the motor-side gear segments. Preferably, two or more segment disks may form segment disk packages. Preferably, the motors for each package of segment discs may be arranged in series in the shape of an arch. Preferably, the motors for each package of segment discs in an engagement range of the respective motor-side gear segments are arranged in series in the shape of an arch. Preferably, the motors are mounted on a bearing block which encompasses in each case a package of segment discs in their circumferential range. Further preferably, a step-like gradation of an arrangement of the pinions driven by the motors is provided for their engagement with the various motor-side gear segments. Further preferably, at least two step-like gradations are provided, with segment discs located next to each other being driven by motors with pinions assigned to various ones of these step-like gradations and the motor-side gear segments of segment discs lying next to each other being located in different areas of the circumference of the package of segment discs. Relative to its width, the gear rod-like drive engagement of the leaves preferably may be designed differently from the width of the leaf-side gear segment. The bearing block may be equipped on both sides with motors. The radii of all segment disks may be identical. Alternatively, two or more of the segment disks may have differing radii. Similarly, the radii of all of the pinions may be identical. Alternatively, two or more pinions may have differing radii. By using differing radii of the segment disks and/or of the pinions, a stacked arrangement of the motors may be achieved. Preferably, due to the preferred arrangement of motor-side gear segments on corresponding varying radii of the segment discs, the motors are arranged in arch-shaped sequences lying on top of each other. The bearing block may position the pinions indirectly or directly by means of positioning agents in their engagement position opposite the motor-side gear segments. Preferably, the pinions are mounted on axles supported by motor bearings and the latter are mounted on the bearing block. Preferably, the motor bearings each comprise a motor holder for mounting the motor and an axle bearing for bearing the axle. The motor holder and the axle bearing may be made of the same or different materials. Consequently, by choosing appropriate materials for both elements, the properties of these elements may be adjusted separately, such as with regard to their weight and/or with regard to their stability against abrasion and/or with regard to their friction properties. As an example, the motor holders may fully or partially be made of a material lighter than the material of the axle bearings. Preferably, the motor holders may fully or partially be made of one or more of the group consisting of aluminum and titanium, in order to reduce the weight of the multi-leaf collimator. The axle bearings may fully or partially be made of a heavier material, such as one or more of the materials chosen from the group consisting of bronze and brass, specifically bearing bronze. By using a material for motor holder lighter than a material used for the axle bearing, some significant weight reduction may be achieved, in view of the typically large number of motors and axles, such as 80 motors or even more. Further, by using separate parts for the axle bearings and the motor holders, manufacturing of the motor bearings may be simplified and production costs may be reduced. Additionally or alternatively, the axle bearings may fully or partially be made of a material adapted to provide low friction, preferably even without the use of an additional lubricant. Thus, the axle bearings may fully or partially be made of a plastic material. In a further preferred embodiment, the leaf drives may be mounted adjustably, i.e. may be mounted such that a position of the leaf drives relative to the leaves may be adjusted. Preferably, a distance between the leaf drives and the leaves may be adjustable by an appropriate adjustable mounting of the leaf drives. Many ways of adjustable mounting are known to the skilled person. In a preferred embodiment, the adjustable mount comprises at least one excenter mount, such that the position of one or more or all of the leaf drives is adjustable by at least one excenter. Again, by providing the adjustability, manufacturing may be simplified since manufacturing tolerances may be compensated by adjustment, and production costs may be reduced. The position of the leaf drives may be adjusted by grouping, such that a group of leaf drives or even all of the leaf drives may be positioned at once. Therein, the leaf drives may form a unit, wherein the position and/or orientation of the unit may be adjustable. Alternatively, the position of single leaf drives or one or more groups of leaf drives may be adjustable. At least one of the leaf drives may fully or in part be adjustable such that the full leaf drive or at least one part thereof may be adjustable. As used herein, the expression “leaf drive” may refer to one or more elements adapted to position one or more of the leaves. Thus, each leaf drive may comprise the at least one segment disk with the at least one motor-side gear segment and the at least one leaf-side gear segment. Further, optionally, at least one pinion engaging the motor-side gear segment may form part of the leaf drive. Further, optionally, the at least one motor adapted to rotate the pinion may also form part of the leaf drive. Optionally, the gear rod-like drive engagement of the at least one leaf, which is adapted to interact with the leaf-side gear segment of the segment disk, may count as part of the leaf drive, too. The adjustment and/or modification of the position of the leaf drives may be used to modify the engagement of the pivotable leaf-side gear segment into the gear rod-like drive engagement of the leaves. Thus, a slackness and/or backlash of the engagement may be adjusted or, preferably, reduced. Similarly, additionally or alternatively to an adjustable mount of the position of the leaf drives, a relative position of the pinions and/or the motors with regard to the motor-side gear segments of the segment disks may be adjusted. The pinions and/or the motors may be mounted adjustably such that a relative position of the pinions with regard to the motor-side gear segments may be adjusted. Again, this positioning may be used to adjust or even reduce a slackness and/or backlash of the engagement of the pinions into the motor-side gear segments. By providing the adjustability, manufacturing may be simplified since manufacturing tolerances may be compensated by adjustment, and production costs may be reduced. It has to be noted that the above-mentioned ideas of the adjustability of the pinions/motors, the adjustability of the leaf drive and the idea of the multi-part design of the motor bearings are realizable independently from the segmented design of the disks. Thus, these additional ideas may also be realized in other types of multi-leaf collimators. Spacers may be provided between adjoining segment discs that reduce mutual friction to the largest extent. Preferably, the leaves have a trapezoid cross section to the effect that they taper in the direction of a radiation source corresponding approximately to a divergence of beams. The sets of leaves may be tilted relative to an optical path to the effect that no rays can pass through a gap between the leaves. Preferably, the leaf drives are designed in such a way that the leaves of the two sets of leaves can come in contact with each other with their front faces only outside of a center plane of the multi-leaf collimator. In a further aspect of the present invention, which may be combined with the aspect disclosed above or which may be realized independently, a multi-leaf collimator for controlling a shape of a high-energy radiation beam emanating from a radiation source and propagating in a direction of propagation is disclosed, comprising: a plurality of leaves individually displaceable in a direction of displacement that is generally transverse to the direction of propagation, said plurality of leaves having a predefined range of displacement (D) in said direction of displacement, each said leaf including a rack gear extending along the direction of displacement; a plurality of individually rotatable segment disks positioned side by side along a common axis of rotation that is generally transverse to said direction of propagation and to said direction of displacement, each said segment disk corresponding to a respective one of said leaves, each said segment disk including a leaf-side gear segment formed along a first peripheral portion thereof that is engaged with said rack gear of the corresponding leaf to displace that leaf along said direction of displacement according to a motor-controlled rotation of said segment disk around said common axis of rotation; and a plurality of motor-driven pinions, each said motor-driven pinion being engaged with a respective one of said segment disks along a motor-side gear segment formed along a second peripheral portion thereof to provide said motor-controlled rotation thereof;wherein the motor-side gear segments of any two adjacent segment disks are staggered in such a way that they will not abut each other throughout the range of displacement (D) of their corresponding leaves. Preferably, each said motor-driven pinion is coupled to a distinct electrical motor to form a respective plurality of motor-pinion assemblies, wherein said plurality of motor-pinion assemblies are arranged in an arch-like pattern relative to said common axis of rotation of said plurality of segment disks. Said motor-pinion assemblies preferably are mounted on a common bearing block extending peripherally around said plurality of segment disks in an arch-like shape relative to said common axis of rotation, said motor-pinion assemblies being mounted on respective step-like gradations formed in said bearing block along the direction of said common axis of rotation for achieving respective engagement of said motor-driven pinions with said motor-side gear segments of said segment disks. Said motor-driven pinions preferably are wider than their associated motor-side gear segments in a direction of said common axis of rotation. The multi-leaf collimator may further comprise at least one spacer disposed between each adjacent pair of said segment disks for reducing mutual friction therebetween. Said plurality of leaves, said plurality of segment disks, and said plurality of motor-driven pinions collectively may form a first leaf/drive assembly, wherein the multi-leaf collimator further may comprise a second leaf/drive assembly generally similar to said first leaf/drive assembly and disposed on an opposing side of a center plane of the multi-leaf collimator. Said plurality of leaves collectively may have a radiation source-facing side and a patient-facing side opposite said radiation source-facing side, wherein said plurality of segment disks may be disposed on said radiation source-facing side of said plurality of leaves, and wherein each of said plurality of segment disks may have a radius (R) along said first and second peripheral portions thereof that may sufficiently be comparable to said predefined range of displacement (D) of said leaves such that each said leaf may be fully displaced through its range of displacement (D) in less than one full turn of said segment disk, whereby structural compactness of the multi-leaf collimator may be facilitated. Said plurality of leaves in conjunction with said predefined range of displacement (D) may define an overall lateral range (L) in said direction of displacement, wherein said plurality of segment disks and said plurality of motor-pinion assemblies may be configured and dimensioned to be entirely confined within said overall lateral range (L) on said radiation source-facing side of said plurality of leaves. Said segment disk radius (R) preferably is greater than one-half of said predefined range of displacement (D) of said leaves. Said segment disk radius (R) preferably is greater than said predefined range of displacement (D) of said leaves. Preferably, for each of said segment disks, said first peripheral portion thereof containing said leaf-side gear segment is non-overlapping with said second peripheral portion thereof containing said motor-side gear segment. In a further aspect of the present invention which may be combined with one or both of the aspects disclosed above or which may be realized independently, a multi-leaf collimator is disclosed, for controlling a shape of a high-energy radiation beam emanating from a radiation source and propagating in a direction of propagation, comprising: a plurality of leaves individually displaceable in a direction of displacement that is generally transverse to the direction of propagation, said plurality of leaves having a predefined range of displacement (D) in said direction of displacement, said plurality of leaves collectively having a radiation source-facing side and a patient-facing side opposite said radiation source-facing side, each said leaf including a rack gear extending along the direction of displacement; a plurality of individually rotatable segment disks disposed on said radiation source-facing side of said plurality of leaves, said plurality of segment disks being positioned side by side along a common axis of rotation that is generally transverse to said direction of propagation and to said direction of displacement, each said segment disk corresponding to a respective one of said leaves, each said segment disk including a leaf-side gear segment formed along a first peripheral portion thereof that is engaged with said rack gear of the corresponding leaf to displace the corresponding leaf according to a motor-controlled rotation of said segment disk around said common axis of rotation; and a plurality of motor-driven pinions, each said motor-driven pinion being engaged with a respective one of said segment disks along a motor-side gear segment formed along a second peripheral portion thereof to provide said motor-controlled rotation thereof; wherein each of said plurality of segment disks has a radius (R) along said first and second peripheral portions thereof that is sufficiently comparable to said predefined range of displacement of said leaves such that each said leaf can be fully displaced through its range of displacement (D) in less than one full turn of said segment disk; whereby structural compactness of the multi-leave collimator is facilitated. Preferably, each said motor-driven pinion is coupled to a distinct electrical motor to form a respective plurality of motor-pinion assemblies, wherein said plurality of motor-pinion assemblies are arranged in an arch-like pattern relative to said common axis of rotation of said plurality of segment disks. Said motor-pinion assemblies preferably are mounted on a common bearing block extending peripherally around said plurality of segment disks in an arch-like shape relative to said common axis of rotation, said motor-pinion assemblies being mounted on respective step-like gradations formed in said bearing block along the direction of said common axis of rotation for achieving respective engagement of said motor-driven pinions with said motor-side gear segments of said segment disks. Further preferably, said plurality of leaves in conjunction with said predefined range of displacement (D) may define an overall lateral range (L) in said direction of displacement, wherein said plurality of segment disks and said plurality of motor-pinion assemblies may be configured and dimensioned to be entirely confined within said overall lateral range (L) on said radiation source-facing side of said plurality of leaves. Preferably, said segment disk radius (R) is greater than one-half of said predefined range of displacement (D) of said leaves. Said segment disk radius (R) may be greater than said predefined range of displacement (D) of said leaves. The motor-side gear segments of any two adjacent segment disks preferably are staggered in such a way that there will be no angular overlap therebetween throughout the range of displacement (D) of their corresponding leaves. Said motor-driven pinions preferably are wider than their associated motor-side gear segments in a direction of said common axis of rotation. The multi-leaf collimator may further comprise at least one spacer disposed between each adjacent pair of said segment disks for reducing mutual friction therebetween. Said plurality of leaves, said plurality of segment disks, and said plurality of motor-driven pinions collectively preferably form a first leaf/drive assembly, wherein the multi-leaf collimator further may comprise a second leaf/drive assembly generally similar to said first leaf/drive assembly and disposed on an opposing side of a center plane of the multi-leaf collimator. Preferably, for each of said segment disks, said first peripheral portion thereof containing said leaf-side gear segment is non-overlapping with said second peripheral portion thereof containing said motor-side gear segment. For each of said segment disks, said first peripheral portion thereof containing said leaf-side gear segment preferably is non-overlapping with said second peripheral portion thereof containing said motor-side gear segment. As disclosed above, the multi-leaf collimator may have a leaf-side pivotable gear segment located on a segment disc together with a motor-side gear segment engage with the gear rod-like drive engagement, with a pinion drivable by a motor engaging with the motor-side gear segment; by arranging the segment disks side by side for each set of leaves as a package on one axle; and by staggering the motor-side gear segments of two segment discs located next to each other in such a way that they will not abut each other. The compactness of the multi-leaf collimator may further be achieved in accordance with one aspect of the invention by positioning the segment disks on a radiation source-facing side of the leaves, and sizing the segment disks to have a radius that is comparable in dimension to a predefined range of displacement of the leaves. By positioning the segment disks on the radiation source-facing side of the leaves (i.e., in the space “above” the leaves in the direction of the radiation source), the dimension of the multi-leaf collimator along the direction of displacement of the leaves (i.e., the “lateral” dimension of the multi-leaf collimator) may be kept to a minimum, and furthermore the vertical space between the radiation-shaping leaves and the patient can also advantageously be kept to a minimum. As a further advantage, the typically relatively large sizing of the segment disks may provide a relatively large circumference along which to position the driving pinions and their associated electrical motors, thereby allowing for a larger number of motorized pinion assemblies to be used, and therefore a larger number of individually controllable segments disks and their corresponding leaves to be accommodated. The advantage of the multi-leaf collimator in accordance with the invention is that even in the case of extremely thin leaves, each leaf can be assigned a drive without any further ado. In this context it will be possible to arrange these drives in such a way that the drive mechanics and the motors do not project outwardly as seen from the leaves, thereby widening the collimator, but that they can be arranged close to the beam between the leaves and the radiation source. The drives may therefore be located in an interspace that typically is available in any event and where they are the least obtrusive, with the beam being able to exit the irradiation head—which typically essentially consists of the radiation source and the collimator—directly downstream of the opening formed by the leaves so that a position of the opening formed by the leaves for the beam exit will be possible very close to the patient. Moreover, it will be possible to design the motors and the drive line in extremely space-saving, lightweight and compact fashion. The lightweight construction in turn has the advantage that the irradiation head will become lighter and can therefore be moved by a gantry or a robot arm into the various solid angle positions for the individual radiation applications extremely fast and precisely and without any extreme driving forces. This makes a faster move into different solid angle positions possible, thereby shortening the time intervals between the individual radiation applications and thus the treatment period of a patient. This is more pleasant for the latter because he or she needs to be fixed in a certain position for a shorter time. In addition, this will increase the cost effectiveness of the irradiation device. The fact that the motor-side gear segments of two adjacent segment disks may be staggered in such a way that they will not abut each other may serve to prevent an engagement of a pinion with a gear segment not assigned to it even if component measurements or component positions are not exact due to production tolerances. In this way, the tolerance parameters may be kept within an economically justifiable range. The aforementioned measure also may facilitate the advantageous further development of making the pinions wider than the motor-side gear segments. This may reduce, on the one hand, the tolerance requirements of the pinion positioning in relation to the motor-side gear segments even further and, on the other hand, may make it possible to design the leaves with their gear segments extremely thin without the possibility of thereby losing the pinion engagement with the gear segments as a consequence of tolerance deviations. As outlined above, another advantageous and preferred embodiment provides for the motors for each package of segment discs to be arranged strung together in an arch-shaped sequence within the engagement range of the respective gear segments. This makes it possible to string together a great number of motors almost with no distance in between and to house them in the smallest possible space. In this case, the motors are preferably mounted on a bearing block that encompasses one package of segment discs each in their circumferential area. A particularly clear arrangement can be achieved by providing a step-like gradation of the pinions driven by the motors for their engagement with the various gear segments. If such a step-like gradation is provided in the bearing block, motors with driven pinions of the same type of construction may be provided, i.e. of the same axle arrangement and pinion positioning, and the step-like gradation may set the parameters for the positioning relative to the assigned gear segments. A further development provides that at least two step-like gradations of the aforementioned kind may be provided, with segment discs located next to each other being driven by motors with pinions assigned to various of these step-like gradations and the motor-side gear segments of adjacent segment discs being located in various areas of the circumference of the package of segment discs. For example, in the case of two step-like gradations, the motors can be arranged relative to the segment discs in alternating fashion in such a way that in the sequence of the segment discs, one motor is always assigned to one step-like gradation and one motor to the other in alternating fashion. This may then make it possible to arrange the motor-side gear segments of adjacent segment discs in different areas of the circumference of the package of segment discs. Since in this way motor-side gear segments will never be arranged directly next to each other, not even in partial areas, a pinion may protrude laterally beyond the gear segments without being able to engage erroneously with a gear segment of the adjacent segment disc at any time. This makes it possible to provide pinion protrusions relative to the gear segments so that the pinions jut into the area of the nearest segment disc without coming into contact with it. For example, in the case of two step-like gradations, the pinions of a first gradation may be assigned to the 1st, 3rd, 5th, 7th, etc. segment disc and the pinions of a second gradation to the 2nd, 4th, 6th, 8th, etc. segment disc. In that case, the motor-side gear segments of the 1st, 3rd, 5th, 7th, etc. segment disc are arranged in a different circumferential area of the package of segment discs than the motor-side gear segments of the 2nd, 4th, 6th, 8th, etc. segment disc. Thus, for example, the gear segment of the 2nd segment disc has neither an abutting gear segment of the 1st segment disc nor a gear segment of the adjacent 3rd segment disc, making it possible for the pinion interacting with the 2nd segment disc to protrude on both sides without touching the 1st and 3rd segment discs during a positioning movement. This applies correspondingly to all segment discs of the entire package of segment discs. This principle could of course also be realized with three or more of such step-like gradations. Moreover, in the case of the gear rod-like drive engagement of the leaves, collisions caused by tolerance deviations or positioning errors can be avoided by designing the width of the gear rod-like drive engagement of the leaves different than the width of the leaf-side gear segment that interacts with it. The practical implementation may occur in two different ways, either in such a way that the gear rod-like drive engagement of the leaves is wider than the leaf-side gear segment so that it can only engage with this drive engagement. Another design option preferably provides for the gear rod-like drive engagement of the leaves to be designed narrower in this area through a tapering of the leaf, thereby making the leaf-side gear segment wider than the gear rod-like drive engagement of the leaves. In this way, the leaf-side gear segment can only engage with the gear rod-like drive engagement of this leaf because, due to the tapering of the drive engagements of the adjacent leaves, an engagement of the gear segment with the adjacent gear rod-like formations will not be possible if the tolerance deviation does not exceed the degree of these taperings, which, however, is not a very great requirement. One possibility of increasing the number of the compactly arranged motors consists of equipping the optional bearing block with motors on both sides. In this context, on both sides means that the motors protrude in opposite directions away from the leaves, with the axles bearing the pinions being arranged between motor and bearing block where their engagement area is. An even more dense arrangement of the motors preferably can be achieved by arranging the motors above each other in an arch-shaped sequence through the arrangement of motor-side gear segments on corresponding differing radii of the segment discs. In the practical execution, for example, one package of segment discs has the motor-side gear segments with greater radii in an interior area of the package and the motor-side gear segment with smaller radii in an area closer to the exterior. According to such an arrangement principle, two or, in corresponding fashion several, arch-shaped arrangements of motors can be arranged on top of each other on differing radii. These differing radii which, after all, also may effect different transmission ratios should of course be actuated accordingly by a control device in order to initiate the required leaf positions. If the leaf-side gear segments are also located on smaller radii, the gear rod-like drive engagements of the leaves would, of course, have to be increased accordingly so that this engagement can take place. However, this would not be required since the segment discs, after all, execute only pivoting movements in the engagement area of the gear segments so that a segment disc may also have gear segments located on differing radii. Differing axle positions of the segment discs are conceivable as well, as are internal gear teeth systems of doughnut-shaped segment discs. It is advantageously provided for the bearing block to position the pinions directly or indirectly by means of positioning agents in their engagement positions relative to the motor-side gear segments. Directly means, for example, that the pinions are directly positioned at a stopper surface of the bearing block. Indirectly means that the pinions are moved into position at the bearing block via the positioning of some retaining element. The latter could, for example, be done by attaching the pinions on axles that are mounted in a preset manner in motor bearings, with the latter being accordingly positioned and attached on the bearing block. The preferred step-like gradations of the arrangement of motors mentioned above can be achieved, for example, by equipping the at least one bearing block with step-like gradations of accommodations for motor bearings so that in this way, the bearing block may position the pinions indirectly with the aid of the motor bearings. Since the segment discs may execute differing movements, e.g. depending on what position the appurtenant leaf is moved into, they must be freely movable and may not show, if at all possible, any significant mutual friction. It is therefore generally proposed for this embodiment or other embodiments to optionally arrange a spacer between adjacent segment discs. Preferably, the multi-leaf collimator will be designed in such a way that the leaves will have a trapeze-shaped cross section to the effect that they preferably will taper in the direction of the radiation source, approximately following the divergence of the beams. The reason is that the beams used are so strong that the leaves must have a not insignificant strength to be shielded against the radiation in the direction of the beam. As a rule, this amounts to several centimeters. Therefore, the delimitations of the openings for the beam exit should, if at all possible, run in the direction of the beam so as not to create a penumbra which is created when no complete shielding is available for the beam exit opening formed by the leaves due to delimitations not running in the direction of the beam. The leaves of such a multi-leaf collimator preferably are crafted in such a way that they will lie closely on top of each other, preferably at least nearly without any gap. In practice, however, it can not be avoided that tiniest rays will still pass through the gaps of leaves due to surface irregularities even if, as a rule, they lie only within the micrometer range such as below 500 μm, preferably below 200 μm and more preferably below 100 μm or even below 50 μm, below 10 μm or below 5 μm. This may be prevented by tilting the sets of leaves tilted relative to the path of rays in such a way that no ray will be able to pass through the course of the gap no longer aligned in the direction of the beam. Since the gap typically is within the range of a few micrometers, such a tilting may be so minor that it does not run counter to the above-mentioned prevention of the creation of a relevant penumbra. For a tilting moving within the micrometer range typically can not lead to the creation of a significant penumbra. If leaves of two sets of leaves are made to completely contact each other with their front faces because the beam is supposed to be completely shielded in this area, radiation may in some cases of course penetrate there through a gap formed by front faces of the leaves. For this reason it is proposed that the leaf drives may be designed in such a way that leaves of the two sets of leaves will be able to touch each other with their front faces only outside of a center plane of the multi-leaf collimator. In this way, the gap in the area of the abutting front faces of leaves may be removed from the center plane in such a way that it will also have a different course than the course of rays. Since this gap, too, is only within the range of a few micrometers, it will suffice if the front faces touch each other in the range of a few tenths or of a few millimeters outside of the center plane. Summarizing the above-mentioned ideas, the following embodiments of the present invention are specifically preferred: Embodiment 1: Multi-leaf collimator with leaf drives, with two sets of displaceable leaves arranged side by side of each other and facing each other in order to impress a high-energy beam with the shape of an irregularly formed treatment object by enabling each of the leaves to assume a position oriented along the shape of the treatment object by means of the leaf drives, with the leaf drives being designed in such a way that the leaves are each equipped with a gear rod-like drive engagement in a direction of displacement,wherein a pivotable leaf-side gear segment located, together with a motor-side gear segment on a segment disk, engages with the gear rod-like drive engagement, with a pinion drivable by a motor engaging with the motor-side gear segment, wherein the segment disks are arranged side by side for each set of leaves as a package on one axle, and wherein the motor-side gear segments of two segment disks located next to each other are staggered in such a way that they will not abut each other. Embodiment 2: Multi-leaf collimator in accordance with Embodiment 1, wherein the pinions are wider than the motor-side gear segments. Embodiment 3: Multi-leaf collimator in accordance with Embodiments 1 or 2, wherein the motors for each package of segment discs in an engagement range of the respective motor-side gear segments are arranged in series in the shape of an arch. Embodiment 4: Multi-leaf collimator in accordance with Embodiment 3, wherein the motors are mounted on a bearing block which encompasses in each case a package of segment discs in their circumferential range. Embodiment 5: Multi-leaf collimator in accordance with Embodiment 3 or 4, wherein a step-like gradation of an arrangement of the pinions driven by the motors is provided for their engagement with the various motor-side gear segments. Embodiment 6: Multi-leaf collimator in accordance with Embodiment 5, wherein at least two step-like gradations are provided, with segment discs located next to each other being driven by motors with pinions assigned to various ones of these step-like gradations and the motor-side gear segments of segment discs lying next to each other being located in different areas of the circumference of the package of segment discs. Embodiment 7: Multi-leaf collimator in accordance with one of Embodiments 1 through 6, wherein, relative to its width, the gear rod-like drive engagement of the leaves is designed differently from the width of the leaf-side gear segment. Embodiment 8: Multi-leaf collimator in accordance with one of Embodiments 4 through 6, wherein the bearing block is equipped on both sides with motors. Embodiment 9: Multi-leaf collimator in accordance with Embodiments 3 through 8, wherein due to an arrangement of motor-side gear segments on corresponding varying radii of the segment discs, the motors are arranged in arch-shaped sequences, preferably lying on top of each other. Embodiment 10: Multi-leaf collimator in accordance with one of Embodiments 4 through 9, wherein the bearing block positions the pinions indirectly or directly by means of positioning agents in their engagement position opposite the motor-side gear segments. Embodiment 11: Multi-leaf collimator in accordance with Embodiment 10, wherein the pinions are mounted on axles supported by motor bearings and the latter are mounted on the bearing block. Embodiment 12: Multi-leaf collimator in accordance with Embodiment 11, wherein the motor bearings each comprise a motor holder for mounting the motor and an axle bearing for bearing the axle. Embodiment 13: Multi-leaf collimator in accordance with Embodiment 12, wherein the motor holders are made of aluminum and the axle bearings are made of bronze. Embodiment 14: Multi-leaf collimator in accordance with one of Embodiments 1 through 13, wherein the leaf drives are mounted adjustably such that a position of the leaf drives relative to the leaves may be adjusted. Embodiments 15: Multi-leaf collimator in accordance with Embodiment 14, wherein the position of the leaf drives is adjustable by at least one excenter. Embodiment 16: Multi-leaf collimator in accordance with one of Embodiments 1 through 15, wherein spacers are provided between adjoining segment discs that reduce mutual friction to the largest extent. Embodiment 17: Multi-leaf collimator in accordance with one of Embodiments 1 through 16, wherein the leaves have a trapezoid cross section to the effect that they taper in the direction of a radiation source corresponding approximately to a divergence of the high-energy beam. Embodiment 18: Multi-leaf collimator in accordance with Embodiment 17, wherein the sets of leaves are tilted relative to an optical path to the effect that no rays can pass through a gap between the leaves. Embodiment 19: Multi-leaf collimator in accordance with one of Embodiments 1 through 18, wherein the leaf drives are designed in such a way that the leaves of the two sets of leaves can come in contact with each other with their front faces only outside of a center plane of the multi-leaf collimator. Embodiment 20: Multi-leaf collimator in accordance with one of Embodiments 1 through 19, wherein the pinions and/or the motors are mounted adjustably such that the relative position of the pinions with regard to the motor-side gear segments may be adjusted. Embodiment 21: A multi-leaf collimator (MLC) for controlling a shape of a high-energy radiation beam emanating from a radiation source and propagating in a direction of propagation, comprising: a plurality of leaves individually displaceable in a direction of displacement that is generally transverse to the direction of propagation, said plurality of leaves having a predefined range of displacement in said direction of displacement, each said leaf including a rack gear extending along the direction of displacement; a plurality of individually rotatable segment disks positioned side by side along a common axis of rotation that is generally transverse to said direction of propagation and to said direction of displacement, each said segment disk corresponding to a respective one of said leaves, each said segment disk including a leaf-side gear segment formed along a first peripheral portion thereof that is engaged with said rack gear of the corresponding leaf to displace that leaf along said direction of displacement according to a motor-controlled rotation of said segment disk around said common axis of rotation; and a plurality of motor-driven pinions, each said motor-driven pinion being engaged with a respective one of said segment disks along a motor-side gear segment formed along a second peripheral portion thereof to provide said motor-controlled rotation thereof;wherein the motor-side gear segments of any two adjacent segment disks are staggered in such a way that they will not abut each other throughout the range of displacement (D) of their corresponding leaves. Embodiment 22: The MLC of Embodiment 21, each said motor-driven pinion being coupled to a distinct electrical motor to form a respective plurality of motor-pinion assemblies, wherein said plurality of motor-pinion assemblies are arranged in an arch-like pattern relative to said common axis of rotation of said plurality of segment disks. Embodiment 23: The MLC of Embodiment 22, wherein said motor-pinion assemblies are mounted on a common bearing block extending peripherally around said plurality of segment disks in an arch-like shape relative to said common axis of rotation, said motor-pinion assemblies being mounted on respective step-like gradations formed in said bearing block along the direction of said common axis of rotation for achieving respective engagement of said motor-driven pinions with said motor-side gear segments of said segment disks. Embodiment 24: The MLC of Embodiment 21, wherein said motor-driven pinions are wider than their associated motor-side gear segments in a direction of said common axis of rotation. Embodiment 25: The MLC of Embodiment 24, further comprising a spacer agent disposed between each adjacent pair of said segment disks for reducing mutual friction therebetween. Embodiment 26: The MLC of Embodiment 21, said plurality of leaves, said plurality of segment disks, and said plurality of motor-driven pinions collectively forming a first leaf/drive assembly, wherein the MLC further comprises a second leaf/drive assembly generally similar to said first leaf-drive assembly and disposed on an opposing side of a center plane of the MLC. Embodiment 27: The MLC of Embodiment 21, said plurality of leaves collectively having a radiation source-facing side and a patient-facing side opposite said radiation source-facing side, wherein said plurality of segment disks are disposed on said radiation source-facing side of said plurality of leaves, and wherein each of said plurality of segment disks has a radius (R) along said first and second peripheral portions thereof that is sufficiently comparable to said predefined range of displacement of said leaves such that each said leaf can be fully displaced through its range of displacement (D) in less than one full turn of said segment disk, whereby structural compactness of the MLC is facilitated. Embodiment 28: The MLC of Embodiment 27, said plurality of leaves in conjunction with said predefined range of displacement (D) defining an overall lateral range (L) in said direction of displacement, wherein said plurality of segment disks and said plurality of motor-pinion assemblies are configured and dimensioned to be entirely confined within said overall lateral range (L) on said radiation source-facing side of said plurality of leaves. Embodiment 29: The MLC of Embodiment 28, wherein said segment disk radius (R) is greater than one-half of said predefined range of displacement (D) of said leaves. Embodiment 30: The MLC of Embodiment 29, wherein said segment disk radius (R) is greater than said predefined range of displacement (D) of said leaves. Embodiment 31: The MLC of Embodiment 21, wherein, for each of said segment disks, said first peripheral portion thereof containing said leaf-side gear segment is non-overlapping with said second peripheral portion thereof containing said motor-side gear segment. Embodiment 32: A multi-leaf collimator (MLC) for controlling a shape of a high-energy radiation beam emanating from a radiation source and propagating in a direction of propagation, comprising: a plurality of leaves individually displaceable in a direction of displacement that is generally transverse to the direction of propagation, said plurality of leaves having a predefined range of displacement (D) in said direction of displacement, said plurality of leaves collectively having a radiation source-facing side and a patient-facing side opposite said radiation source-facing side, each said leaf including a rack gear extending along the direction of displacement; a plurality of individually rotatable segment disks disposed on said radiation source-facing side of said plurality of leaves, said plurality of segment disks being positioned side by side along a common axis of rotation that is generally transverse to said direction of propagation and to said direction of displacement, each said segment disk corresponding to a respective one of said leaves, each said segment disk including a leaf-side gear segment formed along a first peripheral portion thereof that is engaged with said rack gear of the corresponding leaf to displace the corresponding leaf according to a motor-controlled rotation of said segment disk around said common axis of rotation; and a plurality of motor-driven pinions, each said motor-driven pinion being engaged with a respective one of said segment disks along a motor-side gear segment formed along a second peripheral portion thereof to provide said motor-controlled rotation thereof; wherein each of said plurality of segment disks has a radius (R) along said first and second peripheral portions thereof that is sufficiently comparable to said predefined range of displacement (D) of said leaves such that each said leaf can be fully displaced through its range of displacement (D) in less than one full turn of said segment disk; whereby structural compactness of the MLC is facilitated. Embodiment 33: The MLC of Embodiment 32, each said motor-driven pinion being coupled to a distinct electrical motor to form a respective plurality of motor-pinion assemblies, wherein said plurality of motor-pinion assemblies are arranged in an arch-like pattern relative to said common axis of rotation of said plurality of segment disks. Embodiment 34: The MLC of Embodiment 33, wherein said motor-pinion assemblies are mounted on a common bearing block extending peripherally around said plurality of segment disks in an arch-like shape relative to said common axis of rotation, said motor-pinion assemblies being mounted on respective step-like gradations formed in said bearing block along the direction of said common axis of rotation for achieving respective engagement of said motor-driven pinions with said motor-side gear segments of said segment disks. Embodiment 35: The MLC of Embodiment 33, said plurality of leaves in conjunction with said predefined range of displacement (D) defining an overall lateral range (L) in said direction of displacement, wherein said plurality of segment disks and said plurality of motor-pinion assemblies are configured and dimensioned to be entirely confined within said overall lateral range (L) on said radiation source-facing side of said plurality of leaves. Embodiment 36: The MLC of Embodiment 32, wherein said segment disk radius (R) is greater than one-half of said predefined range of displacement (D) of said leaves. Embodiment 37: The MLC of Embodiment 36, wherein said segment disk radius (R) is greater than said predefined range of displacement (D) of said leaves. Embodiment 38: The MLC of Embodiment 32, wherein the motor-side gear segments of any two adjacent segment disks are staggered in such a way that there will be no angular overlap therebetween throughout the range of displacement (D) of their corresponding leaves. Embodiment 39: The MLC of Embodiment 38, wherein said motor-driven pinions are wider than their associated motor-side gear segments in a direction of said common axis of rotation. Embodiment 40: The MLC of Embodiment 39, further comprising a spacer agent disposed between each adjacent pair of said segment disks for reducing mutual friction therebetween. Embodiment 41: The MLC of Embodiment 32, said plurality of leaves, said plurality of segment disks, and said plurality of motor-driven pinions collectively forming a first leaf/drive assembly, wherein the MLC further comprises a second leaf/drive assembly generally similar to said first leaf-drive assembly and disposed on an opposing side of a center plane of the MLC. Embodiment 42: The MLC of Embodiment 32, wherein, for each of said segment disks, said first peripheral portion thereof containing said leaf-side gear segment is non-overlapping with said second peripheral portion thereof containing said motor-side gear segment. FIG. 1 shows a schematic diagram of a multi-leaf collimator 1 in a top view. A multi-leaf collimator 1 consists of two sets 4, 4′ of leaves 3, 3′, 3″ . . . that are displaceable in the direction of the double arrow 7. In this way it will be possible to impress the re-created shape 6′ of a treatment object 6 (see FIG. 2) upon a high-energy beam 5 (see FIG. 2). In this case, the leaves 3, 3′, 3″ . . . may be brought together as shown in FIG. 1 by way of leaves moved together 3B, or they remain moved apart to create the re-created shape 6′ of the treatment object 6 as shown in FIG. 1 by way of leaves separated 3A. When the leaves 3, 3′, 3″ . . . are moved together, their front faces 29 touch each other but not in a center plane 30 of the multi-leaf collimator 1 but somewhat offset so that a gap 27 created between two front faces 29 preferably will not lead to a beam being able to pass through this gap 27. In the case of such an offset relative to the center plane 30, the gap 27 has a different alignment than the course of the high-energy beams 5 and a beam can not pass through. However, the leaves 3, 3′, 3″ . . . preferably are crafted so precisely that such a gap 27 typically will lie within the range of a few tenths or hundredths of a millimeter. FIG. 2 shows a diagram of the principle of a multi-leaf collimator 1 in a cut view. Here, a radiation source 25 is represented, starting from which the high-energy beam 5 collides with the multi-leaf collimator 1, thereby receiving the re-created shape 6′ of a treatment object 6. This re-created shape 6′ typically should of necessity be smaller than the treatment object 6, corresponding to the divergence of the high-energy beam 5, so that it can be hit with great accuracy by the high-energy beam 5 without adjacent tissues being irradiated. An irradiation head 38 is drawn schematically, showing that a free structural space 39 is available for leaf drives 2 between the radiation source 25 and the multi-leaf collimator 1 on both sides of the high-energy beam 5. FIG. 2 also shows that the leaves 3, 3′, 3″ . . . may have a trapeze-shaped cross section so that a course of the lateral delimitations of the leaves 3, 3′, 3″ . . . is created that corresponds to the course of the high-energy beam 5. In this way, the creation of a penumbra may be avoided that typically would occur in the case of rectangular leaves since then, an area of partial shielding of the high-energy beam 5—that is, not provided by the entire thickness of the material of the leaves 3, 3′, 3″ . . . —would be created. However, there is also the problem here that between the individual leaves 3, 3′, 3″ . . . , the gaps 27 may be created at their lateral delimitations, thereby creating radiation leaks in the shielding area. This is avoided by slightly tilting the multi-leaf collimator 1 relative to the course of the high-energy beam 5. This means that a center 28 at which imaginary continuations of the leaf delimitations converge may be slightly offset relative to the radiation source 25. This is depicted here in greatly exaggerated form for the purpose of visualization. Since the gap 27 typically lies within the range of a few hundredths of a millimeter, a distance of the center 28 at which imaginary continuations of the leaf delimitations converge from the radiation source 25 within the range of a few tenths of a millimeter typically will suffice to prevent a significant recurrence of the penumbra avoided by means of the aforementioned measure. In this case, the representation of the irradiation head 38 may be reduced by a multiple relative to its actual size. FIG. 3 shows a leaf drive 2 in accordance with the invention and a base frame 35 for a description of the functional principle. In the representation of FIG. 3, parts of the leaf drive 2 and of the base frame 35 have been omitted so as not to overload the drawing and to leave essential parts visible. Since a set 4, 4′ of leaves 3, 3′, 3″ . . . is located on either side of the high-energy beam 5, a drive unit of the leaf drive 2 should be arranged on either side of the high-energy beam 5 as well. However, of the leaves 3, 3′, 3″ . . . , only one is represented symbolically; the number of leaves 3, 3′, 3″ . . . for each set 4, 4′ typically should lie within a range that lies within a magnitude of 30 to 100. Preferably all of the leaves 3, 3′, 3″ . . . are mounted by means of guiding devices 36 and are driven by the leaf drive 2. The leaf drive 2 in accordance with the invention may consist of two packages 15 of segment discs 11, 11′, 11″, . . . , with their number preferably corresponding to the number of leaves 3, 3′, 3″ . . . of a set 4, 4′ of leaves, thus preferably within the magnitude indicated above. The segment discs 11, 11′, 11″, . . . of a package 15 of segment discs 11, 11′, 11″, . . . are mounted on an axle 33 which in turn is attached to the base frame 35 by means of at least one bearing block 34. The base frame 35 is shown in FIG. 5. Preferably, each segment disc 11, 11′, 11″, . . . bears a leaf-side gear segment 9, 9′, 9″, . . . that interacts with a gear rod-like drive engagement 8, 8′, 8″ . . . (also called rack gear) of a leaf 3, 3′, 3″ . . . as well as, in a different circumferential area, a motor-side gear segment 10, 10′, 10″, . . . , with which a pinion 13, 13′, 13″ driven by a motor 12, 12′, 12″, . . . engages in order to drive the respective segment disc 11, 11′, 11″, . . . so that the respective leaf 3, 3′, 3″ . . . can be moved into the desired position. This is indicated by the double arrow 7 (displacement direction of the leaf) below the symbolically represented leaf 3, 3′, 3″ . . . . Preferably, the motors 12, 12′, 12″, . . . are kept in their position by means of a bearing block 16 which preferably is also arranged on the base frame 35 so that an arch-shaped sequence 31 of motors 12, 12′, 12″, . . . may be created along the engagement range of the pinions 13, 13′, 13″, . . . . As illustrated, more motors 12, 12′, 12″, . . . can be accommodated by equipping the bearing block 16 on both sides with protruding motors 12, 12′, 12″, . . . . From the representation of FIG. 3 it can also be seen how the arrangement of the leaf drives 2 above the leaves 3, 3′, 3″ . . . is possible, thereby allowing the use of a free structural space 39 (see FIG. 2) between the leaves 3, 3′, 3″ . . . of the multi-leaf collimator 1 and the radiation source 25. This is a great advantage of the invention since the irradiation head 38 (see FIG. 2) in which the multi-leaf collimator 1 and the radiation source 25 preferably are arranged does not need to be designed wider because of the leaf drive 2 nor is the space below the leaves 3, 3′, 3″ . . . obstructed by drive elements, allowing the multi-leaf collimator 1 to be moved very close to the treatment object 6. FIG. 4 shows a fragmented representation of components of a leaf drive 2 to explain the principle of the invention. For an explanation of the principle, only a part of the segment discs 11, 11′, 11″, . . . of a package 15 of segment discs 11, 11′, 11″, . . . is shown here. Also, only one leaf 3, 3′, 3″ . . . is represented symbolically which represents all leaves 3, 3′, 3″ . . . that may be positioned by means of the leaf drive 2 in the manner described before. The purpose of this representation is the description of an advantageous further embodiment of the invention which consists of a suitable allocation of motors 12, 12′, 12″, . . . with pinions 13, 13′, 13″ . . . to the motor-side gear segments 10, 10′, 10″, . . . . To assure that the pinions 13, 13′, 13″, . . . driven by the motors 12, 12′, 12″, . . . , the pinions 13, 13′, 13″, . . . should be staggered in such a way that each pinion 13, 13′, 13″, . . . is allocated to a motor-side gear segment 10, 10′, 10″, . . . of the segment discs 11, 11′, 11″, . . . . This staggered arrangement of pinions 13, 13′, 13″ . . . may be carried out in two gradations 17, 17′ in the following manner: In the case of the package 15 of segment discs 11, 11′, 11″, . . . , the motor-side gear segments 10, 10′, 10″, . . . may be arranged in two different circumferential areas in such a way that the alternating arrangement will not lead to any directly adjacent motor-side gear segments 10, 10′, 10″, . . . . In FIG. 4, one segment disc 11 has a motor-side gear segment 10 that extends into the area of the left half of the illustration. The motor-side gear segment 10′ of the adjacent segment disc 11′ is offset in such a way that it will not abut the gear segment 10 but instead extend into the right half of the illustration. Only the subsequent segment disc 11″ has a motor-side gear segment 10″ that may be located in the same circumferential area of the package 15 of segment discs 11, 11′, 11″, . . . as the first motor-side gear segment 10, and so forth. Thus, there may be a distance between these two motor-side gear segments 10 and 10″ that approximately may correspond to the width of the intermediary segment disc 11′. However, this distance may be larger by a minor amount since spacers 24, 24′, 24″ . . . may be arranged between all segment discs 11, 11′, 11″, . . . in order to preferably prevent any friction between adjacent segment discs 11, 11′, 11″, . . . . In a corresponding manner, on the other side, i.e. the right half of the illustration, the motor-side gear segment 10′ of the segment disc 11′ may not followed by the subsequent motor-side gear segment 10″ since it may be located in the left half of the picture but by the motor-side gear segment 10′ of the segment disc 11″ to the effect that a distance between gear segments 10′ and 10′″ exists here as well. For the engagement with the respective motor-side gear segments 10, 10″, . . . on the one side and of the motor-side gear segments 10′, 10′″, . . . on the other side, the allocated motors 12, 12″, . . . as well as 12′, 12′″, . . . may be arranged in the at least two gradations 17 and 17′ on each side. Such an arrangement can be achieved, for example, by means of the bearing block 16 as described earlier in FIG. 3. The purpose of this designs lies in the fact that the pinions 13, 13′, 13″, . . . may be somewhat wider than the allocated motor-side gear segments 10, 10′, 10″, . . . , preferably without any engagement with a gear segment 10, 10′, 10″, . . . of the adjacent segment disc 11, 11′, 11″, . . . being possible. Each segment disc 11, 11′, 11″, . . . preferably has a leaf-side gear segment 9, 9′, 9″, . . . on the underside of the segment discs 11, 11′, 11″, . . . . They engage with gear rod-like drive engagements 8, 8′, 8″, . . . of the leaves 3, 3′, 3″, . . . . In this case, an erroneous engagement with the gear rod-like drive engagement 8, 8′, 8″, . . . of an adjacent leaf 3, 3′, 3″, . . . may be avoided by the fact that the leaf-side gear segments 9, 9′, 9″, . . . may be somewhat tapered relative to the thickness of the segment discs. Conversely, of course, the respective gear rod-like drive engagement 8, 8′, 8″ . . . may be somewhat tapered relative to the thickness of a leaf 3, 3′, 3″ . . . so that an engagement of a leaf-side gear segment 9, 9′, 9″, . . . with a gear rod-like drive engagement 8, 8′, 8″ . . . not allocated to it preferably may not occur. With regard to the leaves 3, 3′, 3″ . . . , it can also be seen that outside of their shielding range they may have punched out holes 32, preferably through holes, that may serve to reduce their weight. This area may overlap with the area in which the gear rod-like drive engagement 8, 8′, 8″, . . . is located. The motors 12, 12′, 12′″ . . . may be mounted on motor bearings 20 than can be attached for example to the at least one optional bearing block 16. This representation, as mentioned before, is fragmentary in order to describe the principle. In reality, a great number of leaves 3, 3′, 3″, . . . per set 4 or, respectively, 4′ of leaves may be arranged in the described manner, with the leaves 3, 3′, 3″, . . . being driven in the corresponding manner by means of segment discs 11, 11′, 11″, . . . . FIG. 5 shows an embodiment of a leaf drive 2 in accordance with the invention that is installed into the base frame 35. The bearing blocks 34 for the axles 33 on which the segment discs 11, 11′, 11″, . . . are mounted are attached to this base frame 35. The bearing blocks 34 may be attached to this base frame 35 as well. They bear the motors 12, 12′, 12″, . . . with the aid of the motor bearings 20 and position the pinions 13, 13′, 13″, . . . in their engagement position. Since in this representation the motors 12, 12′, 12″, . . . protruding forward are completely drawn in, the arch-shaped sequence 31 of the motors 12, 12′, 12″, . . . is well visible. This clearly shows how the motors 12, 12′, 12″, . . . may be densely packed and arranged in neat fashion. FIG. 6 shows a bearing block 16 for an arrangement of motor bearings 20 with motors 12, 12′, 12″, . . . and pinions 13, 13′, 13″ . . . . This bearing block 16 may be constructed in such a way that it can bear motor bearings 20 on both sides, thereby making an arrangement of a multitude of motors 12, 12′, 12″, . . . possible. In the case of the bearing block 16 shown, for example, 40 motors 12, 12′, 12″, . . . to drive a set 4 or 4′ of leaves 3, 3′, 3″ . . . are possible. This number may of course be reduced or be further increased. In the case of bearing block 16 it can also be seen that the motor bearings 20 (see FIG. 7) can be arranged in at least two gradations 17 and 17′ in order to be able to realize the arrangement principle described in FIG. 4. FIG. 7 shows a motor bearing 20 to which a motor 12 has been added by means of motor mountings 37 so that an axle 14 is located in a bearing 22. As an example, the axle 14 may fully or partially be made of steel. A pinion 13 is positioned onto this axle 14 by means of a mounting 21, for example a bolt. A boring 23 may serve the attachment of the motor bearing 20 on the bearing block 16. All motor bearings 20 of this type may be constructed in the same manner using the bearing blocks 16 described above since the bearing block 16 already may provide the gradations 17, 17′ for the positioning of the pinions 13, 13′, 13″, . . . according to their engagement with the motor-side gear segments 10, 10′, 10″, . . . . FIG. 8 shows by way of an example of a motor bearing 20 the latter's attachment to a bearing block 16. The pinions 13, 13′, 13″, . . . drawn in without the motor bearing 20 illustrate how they are positioned in gradated fashion. In this way, such a bearing block 16 presets the respective gradations 17 and 17′ for the arch-shaped sequence 31 of motors 12, 12′, 12″, . . . , preferably on the front side as well as on the rear side of the bearing block 16 so that a great number of motors 12, 12′, 12″, . . . can be arranged in accordance with the principle described. FIG. 9 also shows a schematic diagram of a further embodiment by means of which even more motors 12, 12′, 12″, . . . can be positioned. If one arranges segment discs 11, 11′, 11″, . . . of a package 15 in such a way that in a center sector of the package 15 of segment discs 11, 11′, 11″, . . . , motor-side gear segments 10, 10′, 10″, . . . are located on a larger radius than further outside in the package 15, motors 12, 12′, 12″, . . . can be provided in two arch-shaped sequences 31, 31′ lying on top of each other. In this way, it will be possible to arrange even more motors 12, 12′, 12″, . . . in order to drive even more leaves 3, 3′, 3″, . . . in a manner in accordance with the invention if, for example, thinner leaves 3, 3′, 3″, . . . are provided for a better recreation of the re-created shape 6′ of a treatment object 6, or if the multi-leaf collimator 1 has a relatively large-area design in order to irradiate large treatment objects 6. In any event, in this way leaf drives 2 may also be constructed that are equipped with over 100 leaves 3, 3′, 3″, . . . per set 4, 4′. Of course, even more tiers of motors 12, 12′, 12″, . . . will be possible in corresponding fashion as well. FIGS. 10A-10B illustrate, for purposes of further description of a potential embodiment of the present invention, a conceptual side view of one particular segment disk 11′, along with its associated motor-driven pinion 13′, and its associated leaf 3′ when the leaf 3′ is at the two most extreme positions along the direction of displacement 42 of the leaves. FIGS. 11A-11C illustrate, for purposes of further description of a potential embodiment of the present invention, a conceptual side view of two adjacent segment disks 11′ and 11″, their correspondingly adjacent motor-driven pinions 13′ and 13″, and their correspondingly adjacent leaves 3′ and 3″, when the adjacent leaves 3′ and 3″ are at different combinations of extreme positions along the direction of displacement 42. Referring now to FIGS. 10A-10B and FIGS. 11A-11C, provided is a multi-leaf collimator 1 (MLC) for controlling a shape of a high-energy beam 5 emanating from a radiation source 25 (not shown) and propagating in a direction of propagation 41. It is to be appreciated that the particular orientation of the elements shown relative to a treatment room coordinate system (e.g. x-y-z axes) in FIGS. 10A-10B is only one special case, because the MLC 1 may be in any of a variety of different orientations during a treatment session. As illustrated in FIGS. 10A-10B, the leaf 3′ is individually displaceable relative to all of the other leaves 3, 3″, . . . in a direction of displacement 42 that is generally transverse to the direction of propagation 41. The leaves including leaf 3′ may have a predefined range of displacement “D” in the direction of displacement 42. The plurality of leaves 3, 3′, 3″, . . . collectively having a radiation source-facing side 46 (the “upper” side in FIGS. 10A-10B) and a patient-facing side 47 (the “lower” side) opposite the radiation source-facing side 46. Shown on the leaf 3′ is the rack gear 8′ extending along the direction of displacement 42. As illustrated, the individually rotatable segment disks 11, 11′, 11″, . . . including segment disk 11′ are preferably disposed on the radiation source-facing side 46 of the plurality of leaves 3, 3′, 3″, . . . , adding to the space savings and other advantages of the present invention. The plurality of segment disks 11, 11′, 11″, . . . . Preferably are positioned side by side along a common axis of rotation 43 that is generally transverse to both the direction of propagation 41 and the direction of displacement 42. Each segment disk 11, 11′, 11″, . . . corresponds to a respective one of the leaves 3, 3′, 3″, . . . . Referring now to the segment disk 11′ of FIGS. 10A-10B, the segment disk 11′ includes a leaf-side gear segment 9′ formed along a first peripheral portion 45′ thereof that is engaged with the rack gear 8′ of the leaf 3′. The leaf 3′ is displaced in the direction of displacement 42 according to a motor-controlled rotation of the segment disk 11′ around the common axis of rotation 43 as provided by the motor-driven pinion 13′. The motor-driven pinion 13′ is engaged with the motor-side gear segment 10′ formed along a second peripheral portion thereof 44′ of the segment disk 11′. Preferably, in one particularly advantageous embodiment of the present invention, the segment disk 11′ has a radius R that is sufficiently comparable to the predefined range of displacement D of the leaf 3′ such that the leaf 3′ can be fully displaced through its range of displacement D in less than one full turn of the segment disk 11′. This relatively large sizing of the segment disks provides a relatively large circumference along which to position the driving pinions 13, 13′, 13″, . . . and their associated motors 12, 12′, 12″, . . . , preferably electrical motors, thereby allowing for a larger number of motorized pinion assemblies to be used, and therefore a larger number of individually controllable segments disks 11, 11′, 11″, . . . and their corresponding leaves 3, 3′, 3″, . . . to be accommodated. In one embodiment, the radius R is greater than one-half of D. In another embodiment, the radius R is greater than D. For the particular example of FIGS. 10A-10B, it is also the case that the first peripheral portion 45′ of segment disk 11′ containing the leaf-side gear segment 9′ is non-overlapping with the second peripheral portion 44′ containing the motor-side gear segment 10′, although it is to be appreciated that the scope of the preferred embodiments is not so limited. Further illustrated in FIGS. 10A-10B is an overall lateral range “L” that is defined by the lateral size of the leaves in the direction of displacement along with the extent of the predefined range of displacement D. In one embodiment, the plurality of segment disks 11, 11′, 11″, . . . and the plurality of motors 12, 12′, 12″, . . . and pinions 13, 13′, 13″, . . . are configured and dimensioned to be entirely confined within that overall lateral range L on the radiation source-facing side 46 of the plurality of leaves 3, 3′, 3″, . . . , thereby conveniently occupying a very compact space while at the same time accommodating a relatively large number of individually displaceable leaves 3, 3′, 3″, . . . . According to another advantageous embodiment, the motor-side gear segments of any two adjacent segment disks 11, 11′, 11″, . . . are staggered in such a way that there will be no angular overlap (which can also be referenced as an “abutment”) between those motor-side gear segments 10, 10′, 10″, . . . throughout the predetermined range of displacement of their corresponding leaves 3, 3′, 3″, . . . . Thus, as illustrated in the example of FIGS. 11A-11C, the motor-side gear segment 10′ of segment disk 11′ is strategically disposed along the second peripheral portion 44′, and in a coordinated fashion the motor-side gear segment 10″ of segment disk 11″ is strategically disposed along the second peripheral portion 44″, both in further coordination with the positioning of motor-driven pinions 13′ and 13″, such that even at the two relative displacement extremes of leaves 3′ and 3″ (see FIG. 11B for one extreme and FIG. 11C for the other extreme), there is no angular overlap (abutment) of the motor-side gear segments 10′ and 10″. This can in turn allow, in accordance with another preferred embodiment, the motor-driven pinions 13′ and 13″ to be wider than their associated motor-side gear segments 10′ and 10″, 10″, respectively, in the direction of the common axis of rotation 43. These are just examples of embodiments of a preferred principle of the invention according to which pivotable gear segments 9, 9′, 9″, . . . and 10, 10′, 10″, . . . are interposed between the gear rod-like drive engagements 8, 8′, 8″, . . . of the leaves 3, 3′, 3″, . . . and the motors 12, 12′, 12″, . . . with pinions 13, 13′, 13″, . . . , thereby facilitating a very compact design of the leaf drives 2. This preferred basic idea of the invention makes it possible to realize the compact construction of the leaf drives 2, with the latter being arranged between the leaves 3, 3′, 3″, . . . and the radiation source 25 without increasing or significantly increasing the size of the irradiation head 38 or occupying additional structural space. FIGS. 12A to 12C illustrate a further embodiment of the leaf drive 2 for use in a multi-leaf collimator 1. Therein, FIG. 12A shows a partial perspective overview of the leaf drive 2, FIG. 12B shows a more detailed view of a mounting of the motors 12, 12′, 12″, . . . , and FIG. 12C shows a detailed side view of an adjustable motor mount. For most parts, reference may be made to the embodiments above. In the embodiment of FIGS. 12A to 12C, several possible options are realized in combination, which also might be realized in an isolated way. Firstly, as shown in detail in FIGS. 12B and 12C, the motors 12, 12′, 12″, . . . and/or the pinions 13, 13′, 13″, . . . may be mounted adjustably, such that a relative position of the pinions 13, 13′, 13″, . . . to the motor-side gear segments 10, 10′, 10″, . . . may be adjusted. For simplification purposes, in FIGS. 12A-12C, the segmentation of the segment disks 11, 11′, 11″, . . . is not shown, reference may be made to FIG. 4 in this regard. In order to allow for an adjustment of this relative position, the motor bearings 20 and/or the bearing block 16 may be designed such that adjustment means or positioning means are provided. As shown in the side view of FIG. 12C, the motor bearings 20 may provide elongated holes 48 or slot holes receiving screws, bolts or any other means (not depicted) for mounting the motor bearings 20 to the bearing block 16. One or more threaded holes 49 and/or other anchoring means may be provided in the bearing block 16 in order to receive the means for mounting the motor bearings 20. In FIG. 12C, schematically and for illustrative purposes only, three motors 12, 12′, 12″, . . . are depicted in different adjustment positions with regard to the respective motor-side gear segments 10, 10′, 10″, . . . . Therein, in the left motor 12, 12′, 12″, . . . and left pinion 13, 13′, 13″, . . . , the slack is smallest, whereas in the right motor 12, 12′, 12″, . . . , and pinion 13, 13′, 13″, . . . , by increasing the distance between the pinion 13, 13′, 13″, . . . and the motor-side gear segment 10, 10′, 10″, . . . , the slack is significantly increased. Alternatively or additionally, as the skilled person will recognize, other means for positioning the pinions 13, 13′, 13″, . . . with regard to the motor-side gear segments 10, 10′, 10″, . . . may be provided. Due to the adjustability, a slackness of the engagement of the pinions 13, 13′, 13″, . . . with the motor-side gear segments 10, 10′, 10″, . . . may be adjusted. Consequently, a backlash may be prevented, and production tolerances may be compensated. The negative impacts of these production tolerances, which, typically, may not fully be avoided, thus may be greatly reduced. Further, FIGS. 12A to 12C, show an additional option regarding the design of the motor bearings 20. As shown in FIG. 12B, the motor bearings 20 each may comprise several components. Thus, each motor bearing 20 may comprise an axle bearing 50 for mounting and bearing the axle 14. As an example, the axle bearing 50 may have the shape of a perforated plate having a bearing or bore (not visible) receiving the axle 14. The axle bearing preferably may be made of a material having a high stability against abrasion, such as bronze and/or brass, specifically bearing bronze. Additionally, the motor bearings 20 each may comprise at least one motor holder 51 for mounting the motors 12, 12′, 12″, . . . . The axle bearings 50 may be interposed in between the motor holders 51 and the bearing block 16 and may be held in place by clamping forces. In order to save weight, the motor holders may be made of a lighter material, such as aluminum. As outlined above, the position of the pinions 13, 13′, 13″, . . . may be adjustable, in order to eliminate slackness and/or in order to compensate production tolerances. Similarly, additionally or alternatively, the leaf drives 2, i.e. all of the leaf drives, some of the leaf drives or all of the leaf drives 2 may be mounted adjustably such that a position of the leaf drives 2 relative to the leaves 3, 3′, 3″, . . . may be adjusted. For this purpose, an adjustment mechanism may be provided. In FIG. 12A, one potential embodiment of an adjustable mounting of the leaf drive 2 is depicted. In this embodiment, one or more excenters 52, 52′ are used to adjust a height of the whole block comprising the leaf drive 2 with its components, such as forty segmented disks 11, 11′, 11″, . . . , forty motors 12, 12′, 12″, . . . and pinions 13, 13′, 13″, as well as the bearing block 16, relative to the leaves 3, 3′, 3″, . . . . In FIG. 12A, one of the excenters 52 is depicted in an application orientation, whereas, for illustrative purposes, one excenter 52′ is depicted in reverse orientation, in order to illustrate the excentric tip of the excenter 52′ facing towards the leaf drive 2. The excenters 52, 52′ may be supported by a base or leaf drive bearing, which is not depicted in the figures. By using the excenter 52, 52′, the whole leaf drive 2 may easily be lifted or lowered over a base (not depicted) serving as a bearing for the whole leaf drive 2. Since the leaves 3, 3′, 3″, . . . typically are guided in appropriate guide elements, the gear rod-like drive engagements 8, 8′, 8″, . . . typically all are equal in height. By adjusting the height of the whole leaf drive 2 over these gear rod-like drive engagements 8, 8′, 8″, . . . by using the one or more excenters 52, 52′, the slack may be reduced. Thereby, the backlash may be reduced, and the positioning precision of the leaves 3, 3′, 3″, . . . may be increased. List Of Reference Symbols 1 multi-leaf collimator 2 leaf drive 3, 3′, 3″, . . . leaves 3A leaves separated 3B leaves moved together 4, 4′ set of leaves 5 high-energy beam 6 treatment object 6′ re-created shape of the treatment object 7 double arrow: displacement direction of the leaf 8, 8′, 8″, . . . gear rod-like drive engagement (also called “rack gear”) 9, 9′, 9″, . . . leaf-side gear segment 10, 10′, 10″, . . . motor-side gear segment 11, 11′, 11″, . . . segment disk 12, 12′, 12″, . . . motor 13, 13′, 13″, . . . pinion 14 axle 15 package of segment disks 16 bearing block 17, 17′ gradation 20 motor bearings 21 mounting 22 bearing 23 boring 24, 24′, 24″, . . . spacer 25 radiation source 26 beams 27 gap 28 center at which imaginary continuations of the leaf delimitations converge 29 front face of the leaves 30 center plane of the multi-leaf collimator 31, 31′ arched-shaped sequence of motors 32 holes 33 axle 34 bearing block 35 base frame 36 guiding device 37 motor mounting 38 irradiation head 39 free structural space 41 direction of propagation 42 direction of displacement 43 axis of rotation 44′, 44″ second peripheral portion 45′ first peripheral portion 46 radiation source-facing side 47 patient-facing side 48 49 50 51 52 elongated hole threaded hole axle bearing motor holder excenter in application orientation 52′ excenter in reverse orientation (for illustrative purposes)
	claims	1. One or more tangible computer-readable storage media having computer-executable instructions embodied thereon for performing a method of reliably indicating remaining operating time of a computer based on battery level, the method comprising:for a given computer-usage level, receiving a user-specified time interval that lapses between a battery level draining from a first threshold level to a second threshold level;associating a first level of battery charge with the first threshold level and a second level of battery charge with the second threshold level;determining when the charge remaining in the battery reaches the first level of battery charge associated with the first threshold level and presenting a first low-battery notification based on said determining for the given computer-usage level;determining when the charge remaining in the battery decreases to the second level of battery charge associated with the second threshold level and presenting a second low-battery notification based on said determining for the given computer-usage level; andadjusting at least one of the first threshold level and the second threshold level according to said user-specified time interval, thereby altering at least one of the first level of battery charge and the second level of battery charge at which a notification is received to provide an indication of battery charge remaining according to the user-specified time interval. 2. The media of claim 1, further comprising, in response to the determining that the charge remaining in the battery has reached the first threshold level, altering a calculated rate at which the computer drains charge from the battery. 3. The media of claim 2, wherein the altering of the calculated rate at which the computer drains charge from the battery is accomplished by deactivating components or processes of the computer. 4. The media of claim 1, wherein the user-defined time interval that defines an amount of time that is requested to elapse between the first low-battery notification and the second low-battery notification remains constant with deteriorating battery life. 5. The media of claim 4, wherein adjusting at least one of the first threshold level and the second threshold level maintains the user-specified lapse of time as the battery deteriorates with life. 6. The media of claim 1, further comprising:receiving information that includes criteria useable to identify a defective battery,automatically inspecting the battery to determine whether it satisfies said criteria; andautomatically providing a notification that said battery is defective if the battery satisfies said criteria. 7. The media of claim 1, further comprising monitoring a temperature of the battery, and providing a temperature-warning notification if the battery temperature exceeds a temperature threshold.
	summary
	claims	1. A neutron spectrometer monitor, comprising: a plurality of neutron detectors; said monitor is placed in proximity to a suspected concentration of neutron radiation; each of said plurality of detectors further comprising a rectangular detector means stacked on a titanium proton-absorbing layer, each of said proton-absorbing layers being stacked on a hydrogenous substrate; said hydrogenous substrate being composed of polyethylene and containing hydrogen atoms, said hydrogen atoms interacting with said suspected concentration of neutron radiation, said hydrogenous substrate converting said neutron radiation to a plurality of recoil protons that travel in straight line through said proton-absorbing layer and said detector means, each of said detector means detecting said plurality of recoil protons and further comprising a depleted n/p diode; said hydrogenous substrate deflecting a plurality of scattered neutrons away from said hydrogenous substrate; each of said proton-absorbing layers having a different thickness, d, to absorb a plurality of neutron energies from 1 to 250 MeV; said plurality of neutron detectors being housed in a flat rectangular chamber composed of titanium, said chamber having a polyethylene floor, a plurality of compartments for each of said detector means and a lid; each of said detector means, being coupled to a means for data processing, sends a separate count of recoil protons for each of said different thickness, d, to said data processing means; said data processing means providing said separate count of recoil protons to a means for proton distribution; and said means for proton distribution determines a proton distribution pattern to generate a neutron spectrum pattern that constructs an original neutron spectrum from said suspected concentration of neutron radiation. 2. The neutron spectrometer monitor, as recited in claim 1 , further comprising: claim 1 K count rate values C i ( d i ) i= 1,2 . . . K where for d ixe2x88x921 less than d i less than d i+1 , C ixe2x88x921 ( d ixe2x88x921 ) greater than C i greater than C i+1 . said plurality of recoil protons reaching said detecting mean and producing said separate count of recoil protons that decreases as a neutron energy, E n , decreases; said separate count of recoil protons deceases to zero when a range of maximum energy recoil protons becomes smaller than said different thickness, d, and; said plurality of proton-absorbing layers, further comprising K number of proton-absorbing layers, each of said K number of proton-absorbing layers having said different thickness, d, being exposed to said suspected concentration of neutrons, provides a count rate calculated according to the formula: 3. The neutron spectrometer monitor, as recited in claim 2 , further comprising said plurality of neutron detectors having at least 12 of said detector means. claim 2 4. The neutron spectrometer monitor, as recited in claim 3 , further comprising said chamber serving as an outer shield. claim 3 5. The neutron spectrometer monitor, as recited in claim 4 , further comprising each of said detector means being a solid state detector. claim 4 6. The neutron spectrometer monitor, as recited in claim 5 , further comprising said plurality of neutron detectors having 12 of said detector means. claim 5 7. The neutron spectrometer monitor, as recited in claim 6 , further comprising said polyethylene being solid. claim 6
053135075	description	DETAILED DESCRIPTION OF THE INVENTION FIG. 1 depicts an apparatus for attaching a key member to a nuclear fuel assembly grid and detaching the same therefrom, in accordance with a first embodiment of the present invention. The apparatus is disposed adjacent to a facility for assembling a nuclear fuel assembly, and comprises: a supply and recovery mechanism 20 or means for supplying key members 30 to a prescribed position adjacent to a grid 4 and recovering the same; an inserting and removing mechanism or means for inserting the key members 30 supplied by the supply and recovery mechanism 20 into the grid 4 and removing the key members 30 from the grid 4 to recover the same to the supply and recovery mechanism 20; and a rotating mechanism 50 or means for rotating the key members 30 inserted in the grid 4 in prescribed directions about their longitudinal axes, respectively, to attach the same to the grid and rotating the same in directions opposite to the aforesaid prescribed directions to detach the same from the grid 4. The supply and recovery mechanism 20 comprises a disc shaped rotary stocker 22 and a generally rectangular shaped key magazine 23 adapted to be secured thereto for holding a plurality of elongated key members 30 vertically. The rotary stocker 22 includes a disc shaped body 22a having a vertically extending axis of rotation and a plurality of radially outwardly protruding shafts 21 mounted on an outer peripheral surface thereof in circumferentially spaced relation to one another. The disc shaped body 22a is operably connected to a suitable drive source 20a, so that the rotary stocker 22 is adapted to be rotated thereby about the vertical axis. The key magazine 23 includes a plurality of, e.g., sixteen, vertically extending apertures opening to its bottom face for receiving the key members 30. Each aperture 23a releasably receives therein a single key member 30 so as to deflect the springs 10 on the grid. A suitable mechanism (not shown) for preventing key members 30 from falling as well as allowing the key members to fall at a prescribed timing is provided on the lower open ends of the apertures 23a of the magazine 23. This mechanism may be comprised of a hinged gate or sliding plate and is constructed so that it can be opened and closed at a desired timing. The inserting and removing mechanism comprises a moving mechanism 40 or means arranged between the magazine 23 of the supply and recovery mechanism 20 and the grid 4, and includes an opposed pair of feed rollers 41 and 42 disposed parallel to each other so as to be perpendicular to the longitudinal axes of the key members 30, and a drive mechanism 40a operably connected to the rollers 41 and 42 for rotating each of the rollers in reverse directions. The rotating mechanism 50 includes a pair of upper and lower support members 51 of a rectangular parallelepiped shape arranged at upper and lower sides of a grid 4 which is laid horizontally. Each support member 51 includes a plurality of vertically extending apertures (not shown) formed therethrough so as to correspond to the positions of the key members 30 held by the key magazine 23. The key member is formed of a plate so as to have a strip-like cross-section, and each aperture is formed in an elongated shape so that the key member is prevented from moving angularly when inserted. A plurality of disc shaped worm wheels 52 each having a through aperture formed at an axis thereof for receiving a respective key member 30 are rotatably mounted on each of the support members 51 through suitable connecting means. In addition, a pair of upper and lower horizontal shafts 53, each of which has a plurality of worms 53a formed thereon, are rotatably mounted on the upper and lower support members 51, respectively, such that each worm 53a is held in engagement with a respective worm wheel 52. Furthermore, a gear box 55 having therein a gear assembly and a suitable drive device such as a motor is mounted on a forward end of an arm 70 which is constructed so as to be movable toward and away from the grid 4. In addition, a pair of upper and lower rotatable holders 54 of a cylindrical shape for releasably holding one ends of the shafts 53 are mounted on one side of the gear box 55 so as to be operably connected to the gear assembly therein. The inserting and removing mechanism further includes a discharging mechanism 60 arranged under the lower support member 51, and comprises an elongated push-out plate 61 having an upper groove 61a formed therein so as to extend longitudinally thereof, and an actuator 62 such as a pneumatic cylinder connected to one longitudinal end of the plate 61 for moving the plate 61 vertically. Next, the operation of the apparatus of the aforesaid embodiment will be explained. The key magazine 23 in which the key members 30 are received is attached to one of the protruding shafts 21 of the rotary stocker 22, and the rotary stocker 22 is rotated through a prescribed angle about its axis to position the aforesaid magazine 23 above the grid 4. Then, the suitable key member-falling inhibiting mechanism is operated to cause the key members 30 to fall, whereby the forward ends of the key members 30 are brought into contact with the upper faces of the feed rollers 41 and 42. Subsequently, each of the feed rollers 41 and 42 is rotated in different directions from each other, and each key member 30 is forced into the space between the feed rollers 41 and 42 and is moved downwards by the rotation of the rollers. In this manner, the key members 30 are made to pass through the through apertures of the upper support member 51, and are inserted into the grid 4. The keys thus inserted into the grid 4 are caused to move through the through holes in the lower supporting member 51 to be brought into abutment with the guide groove 61a of the plate 60, and finally stop there. Thereafter, the rotating shafts 53 of the rotating mechanism 50 are secured to the holder 54, and the worms 53a are brought into engagement with the worm wheels 52, respectively. Then, the gear box 55 is activated to simultaneously rotate the upper and lower shafts 53 in the same direction to thereby rotate the key members 90 degrees about their axes through the worm wheels 52. The rotation of the key members 30 allows the springs 10 of the grid 4 to be deflected away from the opposing dimples. The foregoing operation is carried out on every grid 4 to be used for the construction of the nuclear fuel assembly. The fuel rods are then inserted into the grids 4 while deflecting the springs 10 by the inserted key members 30. Thus, the nuclear fuel assembly can be assembled while preventing the fuel rods from abutting the springs 10, and the scratching is prevented from occurring. After the completion of the insertion of all the fuel rods into the grids 4, the key members 30 are removed from the grids 4 in a manner as described below. First, the actuator 62 of the discharging mechanism 60 is activated to lower the position of the elongated plate 61 to some extent. Then, the drive device in the gear box 55 of the rotating mechanism 50 is actuated to rotate the shafts 53 in opposite directions through the holders 54, and the key members are rotated 90 degrees by the worm wheels 52. Thus, the key members 30 are brought back to the initial position and disengage from the springs 10 of the grids 4, so that the key members 30 fall until the lower ends thereof are held in contact with the guide groove 61a of the elongated plate 61. Thereafter, the actuator 62 is activated to elevate the elongated plate 61 to move the key members 30 upwards. Thus, the upper ends of the key members 30 are brought into the lower ends of the feed rollers 41 and 42. Then, the drive mechanism 40a is activated to rotate the feed rollers 41 and 42 in reverse directions opposite to the previous rotating directions. As a result, the key members 30 are moved upwards to be received in the apertures 23a of the magazine 23. Subsequently, while preventing the key members 30 from falling by means of the falling-inhibiting mechanism, the rotary stocker 22 is activated to move the key member-magazine 23 away from the grid 4. After the completion of insertion or removal of the key members, the shafts 53 are removed from the holders 54, and the gear box 55 is moved back to an initial position by operating the arm 70. Thus, in the apparatus of the invention, the attaching and detaching operation of a number of key members 30 can be easily carried out at one time. Therefore, the efficiency of the task of inserting and detaching the key members 30 can be substantially improved compared with the manual operation. In FIG. 1, a half of the key members 30 are elevated while the others are shown as being moved downwards. However, this is simply for the illustration, and in actual situation, all the key members 30 are simultaneously moved up and down. Furthermore, although in the above illustrated embodiment, the supply and recovery mechanism 20 is constructed so as to have a rotary stocker and a magazine, any modification is possible to the construction as long as the modified mechanism can forward the key members 30 to the inserting mechanism. FIGS. 2 and 3 depict an apparatus for attaching and detaching a key member in a nuclear fuel assembly grid in accordance with a second embodiment of the present invention, in which the parts or members common with those of the previous embodiment are designated by the same numerals to simplify the explanation thereof. The apparatus differs from that of the previous embodiment in that the insertion mechanism of the inserting and removing mechanism 40 is replaced by a modified insertion mechanism 140, and that the rotating mechanism 50 is replaced by a modified rotating mechanism 150. First, the insertion mechanism 140 includes two rotatable horizontal support rods 141a and 141b arranged parallel to each other so as to extend perpendicular to the axes of the key members 30, thereby forming a space therebetween through which the key members 30 are conveyed. A pair of feed rollers 143a and 143b are arranged parallel to and outside the support rods 141a and 141b, respectively, through a pair of support plates 142, and an endless timing belt 144 is wound on a respective support rod 141a or 141b and a respective feed roller 143a or 143b disposed adjacent thereto. One end of each support plate 142 is rotatably mounted on a respective support rod, while the other end of the support plate is fixedly secured to the same rod. In addition, arranged adjacent to one ends of the support rods 141a and 141b is an electric motor 146 which includes on its output shaft a first pulley 145 to be engaged with the aforesaid belt 144 wound on one pair of the support rod 141b and the feed roller 143b. Furthermore, a second pulley 145a is interposed between the first pulley 145 on the output shaft of the motor and the belt (not shown) which is wound on the other pair of the support rod 141a and the feed roller 143a. Moreover, a drive cylinder 148 is arranged adjacent to the other ends of the support rods 141a and 141b with its cylinder rod being arranged so as to extend downwards. A rack 147 having gear teeth formed on opposite sides thereof is mounted on the cylinder rod such that the gear teeth on the opposite sides are directed toward the opposed ends of the support rods, respectively. In addition, pinion gear teeth 142a to be engaged with the gear tooth of the rack 147 are formed on the outer surfaces of the ends of the support plates 142 which are disposed in opposed relation to each other. With the above construction, the rollers are caused to move toward and away from each other between a proximity position, in which the rollers engage the key members to move the same, and a distal position in which the rollers do not engage the key members. The modified rotating mechanism 150 includes a plurality of upper cylindrical holding members 151 mounted on the upper support member 51, and a plurality of lower cylindrical holding members 151 mounted on the elongated push-out plate 61. Each holding member 151 is rotatably disposed so as to correspond in its position to a respective key member 30, and has a through aperture 151a through which the key member 30 is inserted. The key member is formed of a plate so as to have a strip-like cross-section, and the through aperture is formed in an elongated shape so that the key member is prevented from moving angularly when inserted. A drive mechanism 154 is operably connected to the holding members 151 for rotating the holding members 151 by a prescribed angle. The drive mechanism 154 includes a pneumatic cylinder device 154b having an elongated plate-like portion 154a formed at a cylinder rod thereof. A plurality of links 153 each having an annular one end are rotatably secured at the other ends to the plate-like portion 154a, and the annular end of each link 153 is fitted on a respective one of the holding members 151. As will be seen from FIG. 2, the upper pneumatic cylinder device is securely fixed to the side wall of the gear box 55, whereas the lower pneumatic cylinder device is immovably disposed on the side face of the base of the elongated plate 61. Furthermore, a plurality of stoppers 51b and 61b are mounted on both the lower face of each of the upper support member 51 and the elongated plate 61, whereby the angular movement of each link is limited within about 90 degrees. Next, the operation of the apparatus of the second embodiment will be described. The magazine 23 is first moved to a position above the grid 4, and then the cylinder device 148 is actuated to move the rack 147 upwards, thereby rotating the support plate 142 to move the feed rollers 143a and 143b towards each other. Then, when the feed rollers 143a and 143b have approached each other so that the space therebetween is generally identical to the width of the key member 30, the driving of the cylinder device 148 is stopped. Subsequently, as is the case with the first embodiment, the key member 30 is moved downwards from the magazine 23 to bring the lower ends of the key members 30 into abutment with the upper faces of the feed rollers 143a and 143b. Then, the motor 146 is activated to rotate the feed rollers 143a and 143b in reverse directions through the gears 145 and the belts 144. As a result, the key members 30 are moved through the holding members 151 of the upper rotating mechanism 150 in a downward direction. Furthermore, in the illustrated embodiment, when the key members 30 are inserted into the grid 4 to some extent, the cylinder device 148 is actuated to move the rack 147 downwards, to thereby move the rollers 143a and 143b away from the key members 30. Therefore, even though the key members 30 are not completely inserted into the grid, the key members 30 can be rotated by actuating the rotating mechanism 50. Accordingly, the work of inserting the key members 30 into the grid 4 becomes easy, enhancing the efficiency of the work. When the key members 30 are moved sufficiently downwards, the lower ends of the key members are fitted into the fitting slits 151a formed in the holding members 151. In this condition, the motor 146 is stopped, and the cylinder device 148 is activated to move the feed rollers 143a and 143b upwards to the initial position. Subsequently, the key members 30 are rotated by means of the upper and lower rotating mechanisms 150. More specifically, the upper and lower pneumatic cylinder devices 154b are driven, and the elongated plates 154a are caused to move along their elongated direction. With this procedure, the holding members 151 are rotated through the link mechanisms 153, and the key members 30 fitted thereinto are rotated. In this connection, the operations of the upper and lower pneumatic cylinder devices 154b are synchronously carried out so that no twisting occurs in the key members 30. In the illustrated apparatus, inasmuch as the stoppers 61b are provided on the lower face of the elongated plate 61, the undue rotation of the links 153 can be prevented. In the foregoing, it is preferable that the slit 151a of the lower holding member 151 be open only at its upper side. With this construction, the positioning of the key members 30 can be carried out by bringing the lower ends of the key members 30 into engagement with the holding members 151. Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
	claims	1. A X-ray waveguide comprising:a core configured to guide X-rays having a wavelength band in which the real part of refractive index of material is smaller than 1; anda cladding configured to confine the X-rays in the core,wherein the core has a one-dimensional periodic structure in which a plurality of layers respectively formed of inorganic materials having different real parts of refractive indices are periodically laminated,the core and the cladding are configured so that a critical angle for total reflection for the X-rays at an interface between the core and the cladding is larger than a Bragg angle due to a periodicity of the one-dimensional periodic structure, anda critical angle for total reflection for the X-rays at an interface between layers in the one-dimensional periodic structure is smaller than the Bragg angle due to the periodicity of the one-dimensional periodic structure. 2. The X-ray waveguide according to claim 1, wherein the number of periods in the periodic structure is greater than or equal to 20. 3. The X-ray waveguide according to claim 1, wherein the inorganic materials, which form the core and have different real parts of refractive index, are at least two types of materials selected from the group consisting of Be, B, C, B4C, BN, SiC, Si3N4, SiN, Al2O3, MgO, TiO2, SiO2, and P. 4. The X-ray waveguide according to claim 1, wherein a material forming the cladding are at least one type of material selected from the group consisting of Au, W, Ta, Pt, Ir, and Os.
	description	FIG. 1 is schematic diagram of an X-ray localizer (visualization) light system 1. In accordance with one embodiment of the present invention an X-ray localizer light system comprises: a long life X-ray localizer light source 10; an optical concentrator 11, light source 10 being situated at a first focal spot F1, optical concentrator 11 being configured for concentrating X-ray localizer light from light source 10 to a second focal spot F2; and an opaque shield 14 having an aperture 16 therein, aperture 16 being situated proximate to second focal spot F2 and being of such a geometrical shape so as to maximize light throughput while meeting light field edge contrast requirements of X-ray localizer light system 1. In a typical X-ray environment, such as a medical system or an industrial system X-ray environment, for example, X-ray source 18 directs X-rays through collimator 22 to a target area 24. One or more mirrors 20 are typically used to direct the light from X-ray localizer light system 1 to target area 24. FIG. 2 is a sectional side view of a more specific embodiment of the X-ray localizer light system of FIG. 1. Typically light source 10 includes a light emitting element 32 surrounded by a light bulb 34. Because light emitting element 32 (typically a filament, for example) is bright and close to light bulb 34, light emitting from element 32 cannot be separated from light bulb 34 that surrounds it. Light element 32 radiates in all directions, while reflector 12 concentrates the light to counteract the spreading. The concentration efficiency of the reflector to the second focal spot depends upon the design of the reflector as well as the aperture and ranges from about five to about eighty percent of the total light. Second focal spot F2 is an enlarged representation of light source 10. The distance of shield 14 and thus aperture 16 from light source 10 can be within a range and need not place aperture 16 exactly at the position of second focal spot F2. As used herein xe2x80x9cproximate to the second focal spotxe2x80x9d is meant to include exactly at second focal spot F2, or within about plus or minus twenty percent of the distance between first and second focal spots F1 and F2 of second focal spot F2. The specific location will vary according to the goals of a system design. If aperture 16 is closer to light source 10 than second focal spot F2, a wider cone angle will occur past aperture 16. If aperture 16 is farther from light source 10 than second focal spot F2, a smaller cone angle will occur past aperture 16. The smaller cone angle has less total light than the larger cone angle but results in more intense light at the target area (that is, higher luminosity). A cone angle is shown in FIG. 2, for example, by lines 40 and 42 which are outer portions of an angle representing a total light field, and by lines 36 and 38 which are outer portions of an angle within the total light field representing a desired light field. When selecting the size of aperture 16, a balance occurs between edge contrast and light throughput. By shrinking the size of aperture 16, the edge contrast is increased at the expense of light throughput. Conversely, by increasing the size of aperture 16, edge contrast is decreased and light throughput is improved. Typically, in medical applications, edge contrast requirements are about 4.5 to about 1 over a distance (of about 6 mm) across the edge with a 1 mm slit or resolution. Edge contrast is measured with a light meter at the bright area which is then moved into the dark area to obtain the bright/dark ratio in luminosity. In one embodiment of the present invention, light source 10 comprises a halogen lamp optimized for long life. Because of inherent tradeoff, halogen lamps with long rated life have significantly lower luminous efficacy than quartz-halogen projector lamps (as much as about 50%). By using the long life halogen lamp in conjunction with other aspects of the present invention to overcome the lower luminous efficacy, sufficient luminosity can be provided to target area 24. In a more specific embodiment, the halogen lamp comprises an axially positioned filament coil (shown in FIG. 2 as light emitting element 32), and each dimension of the coil is smaller than a corresponding dimension of aperture 16. For example, coils typically have a length and a diameter. If aperture 16 is a square shape (as shown by aperture 62 of FIG. 5, for example), both the length and the diameter of the filament coil are selected to be smaller than the side of the square. If aperture 16 is a circle shape (as shown by aperture 64 of FIG. 6, for example), both the length and the diameter of the filament coil are selected to be smaller than the diameter of the circle. In an even more specific embodiment which has been found to reduce off-axis geometrical errors (due to small filament sizes), the filament coil is wound in a helix having a length and a diameter, and the length of the helix is equal to or less than about twice the diameter of the helix. Another useful parameter when selecting light source 10 is robustness. As used herein, xe2x80x9crobustxe2x80x9d means sufficiently capable of withstanding repetitive operation in the intended environment. In the medical X-ray machine environment, for example, a light source is often cyclically turned on for about 60 seconds to about 90 seconds and then turned off for about 60 seconds. Still another useful parameter when selecting light source 10 is the restart voltage. Halogen lamps, for example, have substantially similar (meaning identical or within plus or minus about 10 percent of each other) restart and operation voltages. This property is an advantage as compared with light sources requiring higher restart voltages than operational voltages such as HID lamps. In one embodiment, light source 10 has a restart voltage equal to or less than about 48 volts. In a more specific embodiment, the restart voltage is equal to or less than about 12 volts. When a halogen lamp is used, the power level is typically in a range of about 35 watts to about 150 watts with the optimal value depending upon the filament size and the lumen output. Yet another useful parameter when selecting light source 10 is compactness. In a light emitting context, xe2x80x9ccompactxe2x80x9d means that light emitting element 32 is sufficiently small so that the light from reflector 12 can be directed at aperture 16. In one embodiment, a filament coil is wound in a helix having a length of about 3.5 mm and a diameter of about 1.7 mm. In a size context, xe2x80x9ccompactxe2x80x9d means that the light source size does not result in a need for a larger size of the light system assembly as compared with present light system assemblies. In one example, light bulb 34 is selected to have dimensions with each being about 10 millimeters or less. In a more specific example, light bulb 34 comprises a cylindrical shape having a diameter of about 1 cm and a length of about 1.3 cm. Optical concentrator 11 is configured for concentrating X-ray localizer light from light source 10 to second focal spot F2 with aperture 16 being situated proximate to second focal spot F2 and becoming a virtual light source aligned to the X-ray source. Optical concentrator 11 may comprise one or more lenses (not shown), one or more reflectors, or combinations thereof, for example. In one embodiment, optical concentrator 11 comprises a reflector 12 (meaning at least one reflector 12). In a more specific embodiment, light source 10, reflector 12, and shield 14 are configured to concentrate about 10 percent of total light emitted by the light source 10 through aperture 16. The most intense region of the light about focal spot F2 is typically no more than about 5 millimeters (mm) in diameter, so aperture size of about 4 to 5 mm represents the best tradeoff between light throughput and edge contrast. Reflector 12 typically is a smooth surface reflector comprising a thermally conductive material coated by dichroic mirror material. Examples of appropriate thermally conductive materials include glass and aluminum. Dichroic mirror coatings are useful for reflecting visible light and transmitting heat. In one embodiment, reflector 12 comprises a quasi-ellipsoidal portion 26, and light source 10 is situated within quasi-ellipsoidal portion 26. In a more specific embodiment, light source 10 is attached to reflector 12 with light emitting element 32 centered about first focal spot F1. Quasi-ellipsoidal portion 26 may comprise an elliptical shape or a shape altered from a pure ellipse to improve concentration of light through aperture 16 (in other words, a shape designed to follow a certain curvature). Custom optimization (to accommodate the light source 10 which is not a point source) is readily accomplished via commercially available software tools. In one embodiment, for example, the length (H in FIG. 1) of quasi-ellipsoidal portion 26 is in the range of about 40 mm to about 60 mm, the inner diameter of the quasi-ellipsoidal portion (CA in FIG. 1) ranges from about 45 mm to about 55 mm, and the distance between focal spots F1 and F2 ranges from about 54 mm to about 58 mm. Shield 14 may comprise any structurally suitable opaque material. Mechanically rigid materials that can withstand operating temperatures are particularly useful. In one embodiment, for example, shield 14 comprises aluminum. Although larger thicknesses can be used, a typical example range of shield thicknesses is about 0.5 mm to about 2 mm. Aperture 16 may comprise any polygonal shape. As used herein, a xe2x80x9cpolygonalxe2x80x9d aperture may include an aperture having corners (of any degree) or an aperture having a continuous shape (infinite sides) such as a round or oblong shape. For X-ray system embodiments wherein collimator 22 (shown in FIG. 1) has a square opening, a square aperture is useful for increasing light intensity at the target area without reducing edge contrast. Typically, it is useful to have aperture 16 with a smaller opening facing optical concentrator 11 and a larger opening facing away from optical concentrator 11 as shown in FIG. 4. Due to fact that more light reaches aperture 16 from reflector 12 than directly from light source 10, the light field emanating from aperture 16 is typically darkest in the central region. One way the center can be made brighter is to diffuse some of the surrounding light into the center with an appropriate grade diffuser 60 (shown in FIG. 4) situated between light source 10 and aperture 16. Positioning diffuser 60 close to aperture 16 is particularly useful for improving uniformity of light field at target area 24 (shown in FIG. 1). In one embodiment, for example, diffuser 60 is attached directly to shield 14. In a more specific embodiment, an adhesive 58 such as a high temperature RTV (room temperature vulcanizing) silicone rubber material is used to maintain the attachment of diffuser 60 to shield 14. Several examples of useful materials for diffuser 60 include foggy glass and patterned glass. In either of these embodiments, the diffuser is designed to disperse light across a predetermined range of angles. In medical systems, for example, narrow dispersion angles in the range of about twenty degrees or less are typically useful for maximizing useful light throughput. In one embodiment, the diffuser is square with a side of about 1 cm long and has a thickness of about 0.2 cm. The specific embodiments discussed herein can be used in various combinations to optimize the needs for a particular light system. In one example embodiment, an X-ray localizer light system comprises: a long life halogen lamp 10; a reflector 12 having first and second focal spots, the lamp being situated at first focal spot F1, reflector 12 being configured for concentrating light from the lamp to second focal spot F2; an opaque shield 14 having an aperture 16 therein, aperture 16 being situated proximate to second focal spot F2 and being of such a geometrical shape so as to maximize light throughput while meeting light field edge contrast requirements of the X-ray localizer system; and a diffuser 60 situated between lamp 10 and aperture 16, wherein the halogen lamp comprises an axially positioned filament coil and wherein each dimension of the coil is smaller than a corresponding dimension of aperture 16. FIG. 3 is a sectional side view of a light system in accordance with another embodiment of the present invention. The embodiment of FIG. 3 is useful in the context of X-ray localizer light systems for increasing brightness in the central region of the light field emanating from aperture 16 (either in combination with or separately from the diffuser embodiment) but is not intended to be limited to the context of X-ray localizer light systems. In the embodiment of FIG. 3, reflector 12 additionally comprises a cylindrical portion 30 situated between quasi-ellipsoidal portion 26 and shield 14 for reflecting stray light from the quasi-ellipsoidal portion in the direction of shield 14, a back reflector portion 44 situated proximate to shield 14, and a centrally-mounted portion 46 situated between the aperture and the light source for directing back-reflected light in the direction of aperture 16. Proximate to shield 14 means that the back reflector portion is situated on shield 14 or within about 2.5 millimeters from shield 14. Using the embodiment of FIG. 3, part of the light from beyond the quasi-ellipsoidal portion is reflected back toward the end of the light source and then in the direction of the aperture to yield more light to the center portion. In one embodiment, a transparent cover 48 (comprising a material such as glass, for example) is present between quasi-ellipsoidal portion 26 and cylindrical portion 30, and centrally-mounted portion 46 is attached directly to transparent cover 48. Back reflector portion 44 and centrally-mounted portion 46 are shaped so as to maximize reflection of stray light in the direction of aperture 16. In one embodiment, back reflector portion 44 comprises an elliptically curved surface. Several examples of back-reflected light are shown by light paths 52 and 54 of FIG. 3. Using the embodiment of FIG. 3, the light field from aperture 16 becomes more uniform. The description above with respect to the light source, reflector, shield, aperture, and diffuser embodiments of FIGS. 1-2 and 4-6 is equally applicable to the embodiment of FIG. 3. While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
	summary
	claims	1. A nuclear reactor plant comprising: a casing enclosing a primary space; a reactor vessel, arranged in the primary space; a reactor core provided in the reactor vessel; at least one reactor component sealingly and releasably provided in a through-going opening at a bottom portion of the reactor vessel, wherein said reactor component comprises at least one of a pump device arranged to recirculate liquid within an interior of the reactor vessel, and a driving member arranged to displace a control rod into and out of the reactor core for controlling a nuclear reaction in the reactor core; an upper space provided above the primary space; and a wall portion separating said primary space from said upper space, the reactor core being separated from the upper space by means of an openable cover arrangement, wherein the primary space is limited downwardly by a floor member and a cavity which is open upwardly and extends downwardly from the floor member, and wherein the reactor vessel is at least partly provided within the cavity and said reactor component is provided within the cavity, wherein the casing is designed in such a manner that the primary space is completely closed against the environment at least to a level corresponding to the most highly located part of the reactor core, that the upper space is arranged to house a volume of a liquid, which volume is sufficiently large to permit the filling of the primary space with said liquid to a level reaching at least the most highly located part of the reactor core, and that at least one transport passage extends between the lower part of the cavity and the part of the primary space located above the floor member, said transport passage comprising means for transporting people and material. 2. A nuclear reactor plant according to claim 1 , characterized in that the reactor vessel is provided in the primary space in such a manner that it extends downwardly into the cavity to such a level that the most highly located part of the reactor core is located in the cavity below the floor member. claim 1 3. A nuclear reactor plant according to claim 1 , characterized in that the cavity is defined by a bottom portion and a wall portion which delimit completely the cavity from the surrounding parts of the casing up to the level at which the floor member is located. claim 1 4. A nuclear reactor plant according to claim 1 , characterized in that the casing also encloses a secondary space separated from the primary space and provided below the floor member and arranged to house a cooling medium. claim 1 5. A nuclear reactor plant according to claim 4 , characterized by at least one channel extending through the floor member and connecting the primary space to the secondary space and that said channel has an orifice provided in the secondary space and arranged to be located in said cooling medium. claim 4 6. A nuclear reactor plant according to claim 1 , characterized in that the primary space is accessible from outside via an openable passage, extending through the casing at a level located above the floor member. claim 1 7. A nuclear reactor plant according to claim 1 , characterized in that the cover arrangement comprises a first cover arranged to close an upper limiting wall of the primary space and second cover arranged to close the reactor vessel. claim 1 8. A nuclear reactor plant according to claim 1 , characterized in that the casing is arranged to be permanently closed against the environment up to said level during the operation of the plant and when the plant is shut down. claim 1
	abstract	A method of making a gap between first and second objects have a predetermined value includes steps of introducing light to an entry window on the first object, detecting an intensity of light from an exit window on the first object, and positioning the second object, with respect to a direction concerning the gap, based on an intensity of light detected in the detecting step. The exit window is positioned so that light enters through the entry window of the first object, reflects off the second object, and then enters the exit window of the first object if the gap has the predetermined value.
	claims	1. A method, comprising:providing a garment that substantially contours to an operator's body, but not the operator's head, to protect a portion of the operator's body from radiation, and wherein the garment is suspended from a suspension component, wherein the suspension component includes a bridge configured to ride along one or more rails, and the suspension component includes a trolley that rides along the bridge, and wherein the bridge is capable of providing a purely lateral axis of motion and the trolley is capable of providing a purely linear axis of motion, the garment being configured to secure a face shield thereon, the face shield protecting at least a portion of the operator's head from radiation. 2. The method of claim 1, wherein the suspension component allows the operator, who is wearing the garment to move freely in X, Y, and Z spatial planes simultaneously, and wherein the garment is substantially weightless to the operator. 3. The method of claim 1, wherein the suspension component is operable to support weight of the operator, and wherein the operator can move around with reduced weight. 4. The method of claim 1, wherein the face shield is substantially weightless to operator, and wherein the face shield is substantially transparent to visible light. 5. The method of claim 3, wherein the garment further comprises a flap, the flap being substantially weightless to the operator, and wherein the flap is operable to protect the operator from radiation between the garment and the face shield. 6. The method of claim 1, wherein the garment comprises a removable sleeve, wherein the sleeve is operable to protect the operator from radiation. 7. The method of claim 1, wherein the suspension component is mounted to a ceiling. 8. The method of claim 1, wherein the suspension component further comprises a constant force balancer, wherein the balancer is a selected one of a group of balancers, the group consisting of:a) a spring balancer;b) one or more counterweights;c) a constant force spring;d) a pneumatic balancer;e) an air balancer;f) a spring motor; andg) an intelligent assist device. 9. A system, comprising:providing a garment that substantially contours to an operator's body, but not the operator's head, to protect a portion of the operator's body from radiation, and wherein the garment is suspended from a suspension component, wherein the suspension component includes a bridge configured to ride along one or more rails, and the suspension component includes a trolley that rides along the bridge, and wherein the bridge is capable of providing a purely lateral axis of motion and the trolley is capable of providing a purely linear axis of motion, the garment being configured to secure a face shield thereon, the face shield protecting at least a portion of the operator's head from radiation. 10. The system of claim 9, wherein the suspension component allows the operator, who is wearing the garment to move freely in X, Y, and Z spatial planes simultaneously, and wherein the garment is substantially weightless to the operator. 11. The system of claim 9, wherein the suspension component is operable to support weight of the operator, and wherein the operator can move around with reduced weight. 12. The system of claim 9, wherein the face shield is substantially weightless to the operator, and wherein the face shield is substantially transparent to visible light. 13. The system of claim 12, wherein the garment further comprises a flap, the flap being substantially weightless to the operator, and wherein the flap is operable to protect the operator from radiation between the garment and the face shield. 14. The system of claim 9, wherein the garment comprises a removable sleeve, wherein the sleeve is operable to protect the operator from radiation. 15. The system of claim 9, wherein the suspension component is mounted to a ceiling. 16. The system of claim 9, wherein the suspension component further comprises a constant force balancer, wherein the balancer is a selected one of a group of balancers, the group consisting of:a) a spring balancer;b) one or more counterweights;c) a constant force spring;d) a pneumatic balancer;e) an air balancer;f) a spring motor; andg) an intelligent assist device. 17. An apparatus, comprising:a garment that substantially contours to an operator's body, but not the operator's head, to protect a portion of the operator's body from radiation, and wherein the garment is suspended from a suspension component, wherein the suspension component includes a bridge configured to ride along one or more rails, and the suspension component includes a trolley that rides along the bridge, and wherein the bridge is capable of providing a purely lateral axis of motion and the trolley is capable of providing a purely linear axis of motion, the garment being configured to secure a face shield thereon, the face shield protecting at least a portion of the operator's head from radiation. 18. The apparatus of claim 17, wherein the suspension component allows the operator, who is wearing the garment to move freely in X, Y, and Z spatial planes simultaneously, and wherein the garment is substantially weightless to the operator. 19. The apparatus of claim 17, wherein the suspension component is operable to support weight of the operator, and wherein the operator can move around with reduced weight. 20. The apparatus of claim 17, wherein the face shield is substantially weightless to the operator, and wherein the face shield is substantially transparent to visible light. 21. The apparatus of claim 20, wherein the garment further comprises a flap, the flap being substantially weightless to the operator, and wherein the flap is operable to protect the operator from radiation between the garment and the face shield. 22. The apparatus of claim 17, wherein the garment comprises a removable sleeve, wherein the sleeve is operable to protect the operator from radiation. 23. The apparatus of claim 17, wherein the suspension component is mounted to a ceiling. 24. The apparatus of claim 17, wherein the suspension component further comprises a constant force balancer, wherein the balancer is a selected one of a group of balancers, the group consisting of:a) a spring balancer;b) one or more counterweights;c) a constant force spring;d) a pneumatic balancer;e) an air balancer;f) a spring motor; andg) an intelligent assist device.
046648682	claims	1. A toroidal coil apparatus, comprising: a plurality of coil support frames, each surrounding a common closed loop axis, said plurality of coil support frames having reinforcing members provided on each of said bridge portions immediately adjacent said opposite ends of said straight inner portions, said reinforcing members having keyways and spaces formed therein, the keyways in the reinforcing members on the bridge portions of adjacent coil support frames opposing each other, the spaces in the reinforcing members on the bridge portions of adjacent coil support frames opposing each other; keys inserted in the opposing keyways coupling adjacent coil support frames together; bolts screwed into the reinforcing members of said adjacent coil support frames and having opposite ends extending into the opposing spaces, rigidly securing adjacent coil support frames together. 2. A toroidal coil apparatus as in claim 1, wherein said reinforcing members are formed on opposing side surfaces of the bridge portions of said coil support frames. 3. A toroidal coil apparatus as in claim 1, wherein said coil support frames have inner surfaces facing said closed loop axis and outer surfaces opposite said inner surfaces, said reinforcing members being formed on either said inner surfaces or said outer surfaces of the coil support frames. 4. A toroidal coil apparatus as in claim 1, wherein opposing keyways have dissimilar widths measured in a radial direction with respect to said center axis, and said keys have stepped shapes corresponding the said widths of said keyways. 5. A toroidal coil apparatus as in claim 1, wherein the reinforcing members of adjacent coil support frames have opposing contacting surfaces, said keyways being formed in said opposing contacting surfaces, the keys in said keyways preventing relative sliding of said coil support frames along said opposing contacting surfaces, said opposing contacting surfaces being formed on wall portions of said reinforcing members separating the opposing spaces, said bolts extending through said wall portions into said spaces. 6. A toroidal coil apparatus as in claim 5, wherein said reinforcing members are wedge-shaped and the opposing contacting surfaces of said reinforcing member are continuous with opposing contacting surface of said wedge-shaped coupling portions. 7. A toroidal coil apparatus as in claim 1, wherein said reinforcing members are wedge-shaped and the reinforcing members of adjacent coil support frames have opposing contacting surfaces continuous with opposing contacting surfaces of said wedge-shaped coupling portions.
044709480	abstract	Malfunction under water-solid conditions responsive either to increase in mass flow or increase in heat flow into the reactor coolant is suppressed. The power-actuable reactor-coolant relief valve is opened for increase in reactor-coolant mass influx if the rate of change of coolant pressure exceeds a setpoint during a predetermined interval, if, during this interval, the coolant temperature is less than a setpoint and if the level of the fluid in the pressurizer is above a predetermined setpoint (water-solid state). The interval is set to preclude opening of the relief valve for transients. The relief valve is opened responsive to increased influx of heat to the reactor coolant only while the coolant pump operates for a predetermined interval after it starts, if the level of the fluid in the pressurizer is above a setpoint, if either the difference between the temperature of the secondary fluid in the steam generator and the temperature of the coolant is above a predetermined setpoint or the difference between the temperature of the coolant and of the coolant in the loop seal is greater than a predetermined setpoint and if the coolant temperature is less than the setpoint.
059784326	abstract	The invention is directed to a high-density dispersion nuclear fuel having spherical particles of an uranium alloy dispersed in a nonfissionable matrix. The alloy includes uranium and 4-9 wt % Q, wherein Q is selected from the group consisting of Mo, Nb, and Zr. A process of manufacturing the spherical particles is also disclosed.
055240402	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The high brightness of undulators provide high flux in the resonant bandwidth in the form of a very low divergence beam. This low divergence (vertical divergence .apprxeq.5 arcsec) makes high resolution (.DELTA.EE/E.apprxeq.10.sup.-6) monochromatization in the hard x-ray regime with single crystal silicon practicable. The reason for this is essentially that the beam divergence of these insertion devices approaches the Darwin width of single crystal reflections. As a result, an appreciable fraction of the diverging x-rays in the resonant bandwidth can be accepted. In order to construct such a crystal monochromator with large angular acceptance and high resolution, the requirements for these characteristics will now be examined. The energy resolution for Bragg diffraction from a perfect crystal can be approximated by .DELTA.EE/E.apprxeq..DELTA..THETA.cot.THETA..sub.B, where .THETA..sub.B is the Bragg angle and .DELTA..THETA. is the incident divergence. From the theory of dynamic diffraction of x-rays from perfect crystals, the angular acceptance for a monochromatic beam is the Darwin width, which for symmetrically cut crystals is given by: ##EQU1## where, r.sub.e =classical electron radius, .lambda.=wavelength, .THETA..sub.B =Bragg angle, V=unit cell volume, C=1 for .sigma.-polarized radiation, .vertline.F.sub.H .vertline.=structure factor in the scattering direction, and e.sup.-M =Debye-Waller factor. Typically, an attempt to achieve energy resolution is made with large Bragg angle reflections, since in this case cot(.THETA..sub.s) becomes small. The problem with this strategy is that the Darwin width also becomes small at higher Bragg angles (unless .THETA..sub.s.gtoreq. 80, where .THETA..sub.s increases substantially). Thus, although reasonably good energy resolution is achievable, the beam divergence that can be accepted is exceedingly small. To circumvent this problem, the beam divergence must be reduced to accommodate the narrow acceptance of the higher order reflections. This can be accomplished through the use of asymmetrically cut crystals. By cutting a crystal at an angle (.alpha.) with respect to the diffracting planes, the angular acceptance becomes: EQU .DELTA..THETA..sub.a =.DELTA..THETA..sub.s /b [Eq. 2] where EQU b=sin(.THETA..sub.B -.alpha.)/sin(.THETA..sub.B +.alpha.) [Eq. 3 ] It should be noted that the incident x-rays and the exiting x-rays see opposite asymmetry angles. As a result, the angular acceptance of the incident x-rays will increase, while the allowed divergence of the exiting x-rays will decrease with respect to .DELTA..THETA..sub.s. Thus, an asymmetrically cut crystal has a collimating effect which may be used in combination with a high order reflection to provide high energy resolution with an increased angular acceptance. Then, an optimal combination of Bragg reflections, asymmetry angle, and relative orientation to achieve the desired acceptance and resolution must be determined. For this, DuMond diagrams offer a convenient, graphic means of studying the effect of a multiple crystal diffracting system. Referring to FIG. 1, there is shown a simplified schematic diagram of a radiation detection system 10 incorporating a monochromator 20 in accordance with the principles of the present invention. In the radiation detection system 10, an x-ray beam 12 (shown in dotted-line form) is directed through first and second crystals 14, 16 forming a Si(1 1 1) double crystal monochromator and then through a first ionization chamber 18. In the test set-up, the 24-pole wiggler on the F-2 beam line at the Cornell High Energy Synchrotron Source (CHESS) was used. X-rays from the wiggler were apertured to 6.3 arc seconds vertical divergence before impinging on the water cooled silicon (1 1 1) heat-loaded double crystal monochromator to bring the energy bandpass down to .apprxeq.5 eV. After passing through the first ionization chamber 18, the beam was then passed through the high energy resolution x-ray monochromator 20 of the present invention before passing through a second ionization chamber 30 and impinging on the nuclear resonant medium, an .sup.57 Fe enriched Yttrium Iron Garnet (YIG) crystal 32. Finally, the diffracted beam from the YIG crystal 32 is measured using a fast coincidence photo-multiplier detector 36. Referring to FIGS. 2 and 3, there are respectively shown perspective and front elevation views of the high energy resolution x-ray monochromator 20 of the present invention. A simplified sectional view of the nested pair of crystals within monochromator 20 is shown in FIG. 4. Monochromator 20 includes a first outer asymmetrically cut silicon crystal 21 having facing inner reflecting surfaces 22 and 24. The first outer silicon crystal is of the (4 2 2) type having a channel cut therein to form the first and second reflecting surfaces 22 and 24. The second inner symmetrically cut silicon crystal 25 is disposed within the channel formed in the first outer silicon crystal 21 and includes first and second facing inner reflecting surfaces 26 and 28. The second silicon crystal 25 is asymmetrically cut (.alpha.=20) and is of the (10 6 4) type. The first and second silicon crystals 21 and 25 are arranged in a nested configuration to form a (+m,+n,-n,-m) dispersive geometry as shown in FIG. 4. This design produces an incident angular acceptance of 4.5" and an energy bandpass of 11.7 meV. The asymmetry angle of the first outer silicon crystal 21 was selected based upon a number of criteria. Although angular acceptance was the primary concern, the required alignment between the two channel-cuts in the respective crystals, the effect of too large an asymmetry angle, as well as the overall size of the monochromator 20 were considered as well. The required alignment between the channel-cuts in the respective silicon crystals is dictated by the exiting divergence of the first face and the Darwin width of the second face, i.e., the (10 6 4) crystal. A larger asymmetry angle gives rise to a more restrictive rotational alignment. Large asymmetry angles have another side effect. As .alpha. approaches .THETA., the incident beam becomes glancing and the loss due to diffuse scattering from a rough surface increases. To avoid this, the following condition was established: EQU .THETA.-.vertline..alpha..vertline.>2. [Eq. 4] Also, as the asymmetry angle increases, the size of the diffracted beam increases as S.sub.Diff =S.sub.Inc /b. As a result, the nested channel cuts must be made larger to accommodate the diffracted beam and this, in turn, results in an increase in the overall size of the monochromator. The selected asymmetry angle reflects a consideration of all of these effects. The result is depicted graphically in the DuMond diagram of FIG. 5 for E=14.413 keV. From a transformation of this DuMond plot into the coordinates of the beam incident on the second face, the required rotational alignment between the two crystals was determined to be 0.34 arc seconds for each of the first and second crystals 21,25. To direct a beam of the correct energy through the crystal pair, angular resolution and stability of a factor of 5 or more than illustrated in FIG. 5 is required. The inventive monochromator 20 includes a stainless steel support frame 56 to which are mounted first and second piezo electric, inchworm-driven rotation stages 44 and 46 with angular resolutions of roughly 0.02 arc seconds. In the disclosed embodiment, Burleigh model RS-75 rotation stages are employed. The first and second rotation stages 44, 46 are respectively coupled to first and second inchworms 48 and 50 and are further coupled to first and second angle encoders 52 and 54. The first and second rotation stages 44,46 are respectively coupled to first and second kinematic mounts 40 and 42 which, in turn, are respectively coupled to and provide support for the first outer crystal 21 and the second inner crystal 25. The first and second piezo-inchworms 48 and 50 drive the first and second rotation stages 44 and 46, respectively, for rotationally displacing the first and second crystals 21, 25 relative to one another in tuning the monochromator to a given energy, or bandwidth. The first and second angle encoders 52 and 54 respectively coupled to the first and second rotation stages 44 and 46 provide an accurate indication, or read-out, of the angular position, or orientation, of the two crystals. This arrangement provides an angular resolution of 0.036 arc seconds and an accuracy of on the order of 0.5 arc seconds for each of the first and second crystals 21, 25. Heidenhain model ROD-800 angle encoders are used in the disclosed embodiment. In addition to problems of creep, hysteresis, and the cumulative nature of stepping irregularities in the motion of the first and second inchworms 48, 50, the effects on the Bragg angles due to variations in monochromator-crystal temperature were taken into consideration. Thus, the first and second inchworms 48, 50 are controlled dynamically by software feedback using angle information from the first and second angle encoders 52, 54 and temperature information from a pair of precision thermistors 58 and 60 respectively in contact with the first outer and second inner crystals 21 and 25. The first and second angle encoders 52, 54 are respectively coupled to first and second rotation position indicators 62 and 64. Given adequate feedback control, the performance of monochromator 20 depends critically on mechanical control over three sources of error and the relative angular orientation of the first outer and second inner crystals 21 and 25: (1) The relative orientation of the first and second angle encoders 52, 54; (2) the precision of these two encoders; and (3) the coupling provided by the first and second kinematic mounts 40 and 42 between these crystals and the encoders. To minimize relative motion of the first and second angle encoders 52, 54, the monochromator support frame 56 is fabricated entirely of stainless steel, welded into a unitary piece, stress relieved by heat treatment, and mounted on a vibration-isolated table (not shown for simplicity). The two other sources of error are interdependent: encoder precision depends in part upon the degree to which the encoder shaft is isolated from external forces, and the flexible coupling that can provide this isolation can also introduce hysteresis (shaft windup) in the crystal-encoder connection. In the disclosed embodiment, this connection is made with a Heidenhain model K-15 rotational coupler in the first and second rotation stages 44 and 46. A tilt stage 66 is provided intermediate the second rotation stage 46 and the second kinematic mount 42 as shown in FIG. 3. Tilt stage 66 allows for tilting the first crystal 21 relative to the second crystal 25 to facilitate alignment of the crystals during set-up. Due to the long lifetime, t=98 ns, of the 14.413 keV resonance in .sup.57 Fe when compared to the scattering time for the non-resonant radiation, it is possible to time filter the delayed resonant photons from the prompt non-resonant photons. This can be achieved as long as the non-resonant scattering does not saturate the detector. In order to ensure this, the YIG(002) reflection which is nuclear allowed, but electronically forbidden was used to suppress the non-resonant radiation by a factor of 10.sup.6, or so. From this, a time spectrum without the high resolution monochromator 20 of the present invention was obtained and is shown in FIG. 6. An enormous prompt peak occurs as shown in FIG. 6 despite the six orders of magnitude suppression induced by the electronically forbidden reflection. Highly monochromatic (.DELTA.E/E.apprxeq.10.sup.-11), delayed photons were used to characterize the energy resolution of the high energy resolution, high angular acceptance crystal monochromator 20 of the present invention. To measure the energy bandpass, the inner symmetrical cut silicon crystal 25 (10 6 4) was placed in position and allowed to collect resonant quanta as a function of its rocking angle with the (4 2 2) channel cut remaining fixed. This produced the rocking curve shown in FIG. 7 from which a full width half maximum (FWHM) of 0.7.+-.0.1 arc seconds can be obtained. Transforming this measured FWHM into energy coordinates results in an energy FWHM of 10.8 (.+-.1.6) meV. The full energy bandwidth will be slightly larger than this. The theoretical simulation of this rocking curve involved dispersively convolving the square of the exiting Darwin-Prins curve for the asymmetrically cut (4 2 2) channel cut with that of the symmetrically cut (10 6 4) channel cut. From this a theoretical FWHM of 0.59 arc seconds was obtained. There has thus been shown a 4-bounce dispersive crystal monochromator comprised of an inner symmetrically cut silicon crystal and an outer asymmetrically cut silicon crystal arranged in a nested configuration, with each crystal including a channel cut so as to provide a pair of inner reflecting surfaces. The asymmetrical channel cut outer crystal affords a low order of reflection while providing for the collimating of the diverging x-rays, while the symmetrically cut inner crystal provides high order reflection for reducing the energy bandpass. Compactness and high resolution are achieved by combining the asymmetrically and symmetrically cut crystal in a novel nested geometry, so that the incident x-ray beam is collimated by the asymmetrically cut crystals before high order reflection. The inventive monochromator affords 0.01 eV energy resolution for x-rays at 14,400 eV (or 0.05 eV at 23,870 eV) while maintaining an angular acceptance of 27 microradians. The x-rays monochromatized by the inventive monochromator have an energy resolution better than one part per million. While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
	claims	1. A production device for forming an optical component having a grating structure, said production device comprising:a first light source generating monochromatic and incoherent light of the ultraviolet region;a primary irradiating means for radiating said monochromatic and incoherent light onto a silica-based optical waveguide diffused with at least one of hydrogen or deuterium so as to change a base line level of a refractive index of the silica-based optical waveguide;a second light source generating coherent light; anda secondary irradiating means for radiating said coherent light onto said silica-based optical waveguide so as to produce interference and further change the refractive index of the silica-based optical waveguide,wherein the primary irradiating means is configured to radiate the monochromatic light radiated onto the silica-based optical waveguide without producing interference. 2. The production device of claim 1, wherein the primary irradiating means and the secondary irradiating means are configured to radiate a circumferential surface of the silica-based optical waveguide. 3. The production device of claim 1, wherein said first light source is an excimer lamp. 4. The production device of claim 1, wherein the wavelength of said monochromatic light is 172 nm. 5. The production device of claim 1, wherein the wavelength of said monochromatic light is 222 nm. 6. The production device of claim 1, wherein said primary irradiating means radiates said monochromatic light onto said optical waveguide from multiple directions. 7. The production device of claim 1, wherein said primary irradiating means further comprises:a determining means for determining whether a refractive index of said optical waveguide is a predetermined refractive index; anda control means for controlling the commencement and cessation of radiation of said monochromatic light based on a result of the determination by said determining means. 8. The production device of claim 7, wherein said determining means is a timer for determining a duration of a time of radiation of said monochromatic light. 9. The production device of claim 7, wherein said determining means is an optical power meter which detects a power of said monochromatic light. 10. The production device of claim 7, wherein said determining means comprises an optical fiber grating for use in detecting a change in the refractive index of said optical waveguide. 11. The production device of claim 1, wherein said primary irradiating means comprises:an amplitude mask configured to interrupt said monochromatic light;a means for moving said amplitude mask along said silica-based optical waveguide; anda mask movement controller which controls a speed of movement of said amplitude mask along said silica-based optical waveguide.

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