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040101088	description	In order to illustrate the preferred procedures of the present invention, the following examples are set forth. However, it should be understood that these examples are primarily for the purpose of illustration and any enumeration of detail contained therein should not be construed as a limitation. EXAMPLE 1 Water from a reactor cooling loop containing radioactive isotopes of the iron family is passed through a conduit packed with 1200 mililiters of resin beads, which beads are composed of a cation exchange resin available commercially (specifically a sulfonated styrene-divinylbenzene polymer). In this way, radioactive cationic materials are removed from the water and collected by the resin beads. The water is allowed to drain from the beads and the wet beads are then placed in a five gallon container. A 2000 ml solution or dispersion of urea-formaldehyde resin is then prepared by adding 1200 ml water to 800 ml of a dispersion containing about 63-66% solids. This diluted dispersion is then added to the wet beads in the container, and the mixture stirred by an electric stirrer at a speed sufficient to keep the resin beads substantially evenly distributed in the mixture. 50 ml of a saturated solution of sodium bisulphate is then added gradually with the stirring being continued. After the sodium bisulfate is added and the mixture gels sufficiently to hold the resin beads from sinking by gravity, the stirring is discontinued and the stirring blades disconnected and left in the mixture. The gel is then allowed to set until the cure is complete, whereupon the unit is ready for disposal. EXAMPLE 2 Water from a reactor cooling loop containing radioactive waste is mixed with 1200 ml of powdered ion exchange filter aid available in the trade as Powdex. The Powdex is then filtered and added to a 5 gallon container. A 1200 ml solution or dispersion of urea-formaldehyde resin is then prepared by adding 900 ml water to 300 ml of a dispersion containing about 63-66% solids, and the urea-formaldehyde dispersion added to the five gallon container. The mixture is stirred by an electric stirrer, and 150 ml of a saturated solution of sodium bisulfate is added while continuing the stirring. After the solution gels, the stirring is discontinued and the mixture allowed to cure into a solid thermoset mass. EXAMPLE 3 Water from a reactor cooling loop containing radioactive waste is mixed with 1200 ml diatomaceous earth, and the diatomaceous earth removed by filtration. 1200 ml of urea-formaldehyde dispersion similar to that used in Example 2, and the treated diatomaceous earth is added to a five gallon container. These materials are stirred with an electric stirrer and 100 ml of a saturated solution of sodium sulphate is added. After the solution gels, the stirring is discontinued and the mixture allowed to cure into a solid thermoset mass. EXAMPLE 4 Water from a reactor cooling loop containing radioactive waste is placed in a vacuum and about 80% of the water removed by vacuum evaporation. 900 ml of the evaporated waste water and 1200 ml of a wood celulose flour is added to a five gallon container. 300 ml of a urea-formaldehyde dispersion containing about 63-65% solids is also added. The ingredients are then stirred with an electric stirrer and 150 ml of saturated sodium bisulfate is added. After the solution gels the stirring is discontinued and the mixture is allowed to cure into a solid theremoset mass. EXAMPLE 5 The procedure of Example 4 is repeated, except that the evaporated waste water contains borate moities in the amount of about 20% by weight of the solution calculated as boric acid. Similarly good results are obtained. EXAMPLE 6 Water from a reactor cooling loop containing radioactive waste is flashed in a vacuum to remove about 80% of the water. Another portion of water from the reactor cooling loop is passed through a conduit packed with 1200 ml of ion exchange resin beads similar to those of Example 1. 1200 ml of the evaporated water, the ion exchange resin beads, and 800 ml of a urea-formaldehyde dispersion containing about 63-65% solids are mixed together by an electric stirrer and 50 ml of a saturated solution of sodium bisulphate is added. After the solution gels, the stirring is discontinued and the mixture is allowed to cure into a solid thermostat mass. The samples obtained from the procedures set forth above are compared with similar samples made with Portland Cement. In all cases, the samples made with the urea-formaldehyde were as good as or better than those made with Portland Cement. Of particular note, is the fact that certain of the cement samples did not set at all. Moreover, contact of the other cement samples with sea water caused them to crack, while the resin samples remained intact under similar circumstances. From the foregoing description, it is seen that there has been provided an improved method of disposal of radioactive waste material, and particularly an improvement over the process using cement heretofore in major usage.
	description	The present application is a continuation of U.S. patent application Ser. No. 11/871,090, filed Oct. 11, 2007, which will issue as U.S. Pat. No. 8,067,659, which in turn claims the benefit of U.S. Provisional Application No. 60/850,733, filed on Oct. 11, 2006, the entirety of which is hereby incorporated by reference. The present invention relates generally to the field of transporting and/or preparing high level radioactive waste (“HLW”) for dry storage, and specifically to apparatus and methods for transporting, removing and/or preparing HLW for dry storage from a fuel pool/pond. In the operation of nuclear reactors, the nuclear energy source is in the form of hollow zircaloy tubes filled with enriched uranium, typically referred to as fuel assemblies. When the energy in the fuel assembly has been depleted to a certain level, the assembly is removed from the nuclear reactor. At this time, fuel assemblies, also known as spent nuclear fuel, emit both considerable heat and extremely dangerous neutron and gamma photons (i.e., neutron and gamma radiation). Thus, great caution must be taken when the fuel assemblies are handled, transported, packaged and stored. After the depleted fuel assemblies are removed from the reactor, they are placed in a canister. Because water is an excellent radiation absorber, the canisters are typically submerged under water in a pool. The pool water also serves to cool the spent fuel assemblies. When fully loaded with spent nuclear fuel, a canister weighs approximately 45 tons. The canisters must then be removed from the pool because it is ideal to store spent nuclear fuel in a dry state. The canister alone, however, is not sufficient to provide adequate gamma or neutron radiation shielding. Therefore, apparatus that provide additional radiation shielding are required during transport, preparation and subsequent dry storage. The additional shielding is achieved by placing the canisters within large cylindrical containers called casks. Casks are typically designed to shield the environment from the dangerous radiation in two ways. First, shielding of gamma radiation requires large amounts of mass. Gamma rays are best absorbed by materials with a high atomic number and a high density, such as concrete, lead, and steel. The greater the density and thickness of the blocking material, the better the absorption/shielding of the gamma radiation. Second, shielding of neutron radiation requires a large mass of hydrogen-rich material. One such material is water, which can be further combined with boron for a more efficient absorption of neutron radiation. There are generally two types of casks, transfer casks and storage casks. Transfer casks are used to transport spent nuclear fuel within the nuclear facility. Storage casks are used for the long term dry state storage. Guided by the shielding principles discussed above, storage casks are designed to be large, heavy structures made of steel, lead, concrete and an environmentally suitable hydrogenous material. However, because storage casks are not typically moved, the primary focus in designing a storage cask is to provide adequate radiation shielding for the long-term storage of spent nuclear fuel. Size and weight are at best secondary considerations. As a result, the weight and size of storage casks often cause problems associated with lifting and handling. Typically, storage casks weigh approximately 150 tons and have a height greater than 15 ft. A common problem is that storage casks cannot be lifted by the cranes in typical nuclear power plants because their weight exceeds the rated capacity of the crane. Another common problem is that storage casks are too large to be placed in storage pools. Thus, in order to store spent nuclear fuel in a storage cask, a loaded canister must be removed from the storage pool, prepared in a decontamination station, and transported to the storage cask. Additional radiation shielding is required throughout all stages of the transport and preparation procedures. Removal from the storage pool and transport of the loaded canister to the storage cask is facilitated by a transfer cask. Generally, an empty canister is first placed within an open transfer cask. The transfer cask and empty canister are then submerged in the storage pool. After the fuel assemblies are removed from the nuclear reactor they are placed into the pool, within the submerged canister. While underwater, the loaded canister is fitted with a lid, thereby enclosing water and the fuel assemblies within the canister. The transfer cask, which contains the loaded canister, is then removed from the pool by a crane, or other similar piece of equipment. After being removed from the pool, the transfer cask is placed on a decontamination station to prepare the spent nuclear fuel for long-term storage in the dry state. In the decontamination station the bulk water is pumped out of the canister, thereby reducing the combined weight of the canister and transfer cask. This is called dewatering. Once dewatered, the spent nuclear fuel is further dried to an acceptable level through an appropriate drying method. Once adequately dry, the canister is back-filled with an inert gas, such as helium. The canister is then sealed and a radiation absorbing lid is secured to the transfer cask body. The transfer cask and canister are then transported to the storage cask where the canister will be transferred to the storage cask. In some instances, the transfer cask itself may be used as the storage cask. Transfer casks are designed to be lighter and smaller than storage casks because a transfer cask must be lifted and handled by the plant's crane. A transfer cask must be small enough to fit in a storage pool and light enough so that when it is loaded with a canister of spent nuclear fuel, its weight does not exceed the crane's rated weight limit. Importantly, however, a transfer cask must also perform the vital function of providing adequate radiation shielding for both neutron and gamma radiation emitted by the enclosed spent nuclear fuel. The transfer cask must also be designed to provide adequate heat transfer. Thus, in designing transfer casks and their handling procedures, the desirability of maximizing radiation shielding (which is generally achieved by increasing the mass of the cask's structure) must be balanced against the competing interest of keeping the combined weight of the transfer cask and its payload within the crane's rated weight limit. In order to achieve the necessary gamma and neutron radiation shielding properties, transfer casks are typically constructed of a combination of a gamma absorbing material (e.g., lead, steel, concrete, etc.) and a neutron absorbing material (e.g., water or another material that is rich in hydrogen). The body and lid of the cask, which are generally formed of lead, steel, concrete or a combination thereof, form the cavity in which the spent fuel is to be positioned and function as a containment boundary for all radioactive particulate matter. While the pool water sealed within the canister provides some neutron shielding, this water is eventually drained at the decontamination staging area. Therefore, many transfer casks have either a separate layer of neutron absorbing material or have an annular space filled with water that circumferentially surrounds the cavity of the transfer cask and/or the containment boundary formed by the body. Such annular spaces are typically referred to as water jackets. As stated previously, greater radiation shielding is provided by increased thickness and density of the gamma and neutron absorbing materials. However, increasing the thickness and density of the materials used to make the transfer cask results in a heavier transfer cask. Thus, the extent of radiation shielding is directly proportional to the weight of the transfer cask. The weight of a transfer cask, however, must remain below the rated lifting capacity of the crane. The load handled by the crane includes the weight of the transfer cask and the combined weight of the canister and the fuel assemblies and water (i.e. the transfer cask's payload). A transfer cask must be designed so that the total load does not exceed the rated limit of the crane. Thus, the permissible weight of the transfer cask is the rated lifting capacity of the crane minus the weight of its payload. It is important to note that when the combined weight of the transfer cask and its payload is equal to the rated lifting capacity of the crane, the radiation shielding provided by the transfer cask is at a maximum for that particular payload. This is so because the thickness of the gamma and neutron absorbing materials are at a maximum for that crane and that payload. The weight of the transfer cask's payload varies during the different stages of the transport procedure. The permissible weight of the transfer casks is calculated when the payload is at its maximum. This occurs when the transfer cask is being lifted out of the pool because it contains a loaded canister which is full of about 70 tons of water and the nuclear fuel assemblies. Upon dewatering in the decontamination station, the weight of the transfer cask drops below the rated capacity of the crane and typically remains so throughout the remaining procedures. As such, the radiation shielding provided by the transfer cask is sub-standard throughout the procedure following removal from the storage pool. However, a heavier transfer cask cannot be used throughout the entirety of the transport procedure because the combined weight of the heavier transfer cask and its payload would exceed the rated lifting capacity of the crane during the initial step of lifting the transfer cask from the storage pool. Thus, the maximum amount of radiation shielding is not provided throughout every step of the transfer and dry-storage preparation procedure. While it is possible to transfer the canister of spent nuclear fuel to a heavier transfer cask once the payload is lightened from dewatering, this would take additional time, money, effort, space and equipment: An additional transfer would also increase the amount of radiation exposure to personnel and the risk of a handling accident. A need exists for an apparatus that can provide the maximum amount of shielding throughout all stages of transferring spent nuclear fuel. A need also exists for a method of transferring a canister of spent nuclear fuel from a storage pool that provides the maximum amount of radiation shielding during all stages of the transfer procedure, even when the weight of the transfer cask's load varies. It is an object of the present invention to provide an apparatus that can provide the maximum amount of radiation shielding during all stages of an HLW transfer procedure. Another object of the present invention is to provide an apparatus for transferring HLW, the weight of which can be easily and quickly varied to maximize the amount of radiation shielding for a varied payload without substantially increasing the transfer procedure cycle time. Yet another object of the present invention is to provide an apparatus for maximizing radiation shielding that can be placed around the transfer cask safely and efficiently subsequent to removal from the storage pool. Still another object of the present invention is to provide a method of transferring HLW that provides the maximum amount of radiation shielding during all stages of the transfer procedure, even when the weight of the payload is varied. Yet another object of the present invention is to provide a method of transferring HLW that provides adequate radiation shielding during all stages of the process even when a low capacity crane is utilized. Still another object of the present invention is to provide a method of transferring HLW that minimizes the weight of the apparatus' payload at the initial step of lifting the apparatus out of a storage pool. It is a further object of the present invention to provide an apparatus that can provide a natural thermosiphon circulation of a neutron absorbing fluid within a jacket for facilitating increased cooling of HLW. A still further object of the present invention is to provide a method of transferring HLW from a submerged state in a fuel pool to a staging area that utilizes the buoyancy of the water in the pool. These and other objects are met by the present invention, which is one aspect can be an apparatus for transporting and/or storing radioactive materials comprising: a gamma radiation absorbing body forming a cavity for receiving radioactive material; a jacket surrounding the body thereby forming a gap between the body and the jacket for holding a neutron absorbing fluid; a baffle positioned in the gap in spaced relation to both the body and the jacket so as to divide the gap into an inner region and an outer region; a passageway at or near a bottom of the gap between the inner region and the outer region that allows the neutron absorbing fluid to flow from the outer region into the inner region; and a passageway at or near a top of the gap between the inner region and the outer region that allows the neutron absorbing fluid to flow from the inner region into the outer region In another embodiment, the invention can be a jacket apparatus for providing neutron radiation shielding to a container holding radioactive materials comprising: an enclosed volume formed by a plurality of surfaces comprising an inner wall and an outer wall; a baffle positioned in the enclosed volume in spaced relation to the inner and outer walls so as to divide the enclosed volume into an inner region and an outer region; at least one passageway at or near a top end of the enclosed volume spatially connecting the inner region and the outer region; and at least one passageway at or near a bottom end of the enclosed volume spatially connecting the inner region and the outer region. In another embodiment, the invention can be a method for transporting and/or storing radioactive materials comprising: providing a container having a cavity, a water jacket surrounding the cavity and forming an annular gap filled with a neutron absorbing fluid, a baffle positioned in the annular gap so as to divide the annular gap into an inner region and an outer region, a lower passageway between the inner region and the outer region, and an upper passageway between the inner region and the outer region; positioning radioactive material having a residual heat load in the cavity; and wherein heat emanating from the radioactive materials warms the neutron absorbing fluid in the inner region so as to cause the neutron absorbing fluid to flow upward in the inner region, the warmed neutron absorbing fluid flowing through the upper passageway and into the outer region where it is cooled, the cooled neutron absorbing fluid flowing downward in the outer region and back into the inner region via the lower passageway, thereby achieving a thermosiphon fluid flow. In yet another aspect, the invention can be an apparatus for providing additional radiation shielding to a container holding radioactive materials comprising: a tubular shell extending from a first end to a second end, the tubular shell constructed of a gamma radiation absorbing material and having an inner surface that forms a cavity; a first opening in the first end of the tubular shell that provides a passageway into the cavity; a second opening in the second end of the tubular shell that provides a passageway into the cavity, the second opening being larger than the first opening; and a plurality of spacers extending from the inner surface of the shell. In still another embodiment, the invention can be an apparatus for providing additional radiation shielding to a container holding radioactive materials comprising: a tubular shell constructed of a gamma radiation absorbing material and having an inner surface that forms a cavity having an axis, the cavity having an open top end and an open bottom end; a plurality of spacers extending from the inner surface of the shell toward the axis of the cavity, the spacers extending a first height from the inner surface of the tubular shell; and one or more flange members located at or near the open top end of the cavity extending from the tubular shell toward the axis of the cavity, the flange member extending a second height from the inner surface of the shell, the second height being greater than the first height. In a further aspect, the invention can be a system for handling and/or processing radioactive materials comprising: a container having a first cavity for holding radioactive materials, the container having an outer surface and a top surface; a tubular shell having an inner surface that forms a second cavity for receiving the container, the tubular shell comprising at least one spacer extending from the inner surface of the shell toward an axis of the second cavity; the container positioned in the second cavity of the tubular shell, the at least one spacer maintaining the inside surface of the tubular shell in a spaced relationship from the outer surface of the container; and wherein the tubular structure is non-unitary and slidably removable from the container. In a yet further aspect, the invention can be a method of handling and/or processing radioactive materials comprising: a) placing a container having a first cavity containing radioactive materials in a staging area, the container having an outer surface and a top surface; b) providing a tubular shell having an inner surface that forms a second cavity for receiving the container, the second cavity having an open top end and an open bottom end, the tubular shell also comprising at least one spacer extending from the inner surface of the shell toward an axis of the second cavity; and c) positioning the tubular sleeve above the container and lowering the tubular shell so that the container slidably inserts through the open bottom end and into the second cavity, the at least one spacer maintaining the inside surface of the tubular shell in a spaced relationship from the outer surface of the container so as to form a gap between the container and the tubular shell. In still another aspect, the invention is a method of processing and/or removing radioactive materials from an underwater environment comprising: a) submerging a container having a top, a bottom, and a cavity in a body of water having a surface level, the cavity filling with water; b) positioning radioactive material within the cavity of the submerged container; c) raising the submerged container until the top of the containment apparatus is above the surface level of the body of water while a major portion of the container remains below the surface level of the body of water; and d) removing bulk water from the cavity while the top of the container remains above the surface level of the body of water and a portion of the container remains submerged. In an even further aspect, the invention can be a method of processing and/or removing high level radioactive materials from an underwater environment comprising: a) providing a container having a cavity having an open top end and closed bottom end, the container having a top; b) positioning a canister having an open top end and a closed bottom end in the cavity of the container to form a container assembly; c) submerging the container assembly in a body of water; d) positioning high level radioactive material in the canister; e) placing a lid atop the canister that substantially encloses the top end or the canister, the lid having one or more holes; f) raising the submerged container assembly until the top of the container is above a surface level of the body of water while a major portion of the container remains below the surface level of the body of water; and g) removing bulk water from the canister while the top of the container remains above the surface level of the body of water and a portion of the container remains submerged. In another aspect, the invention can be a method of removing spent nuclear fuel from an underwater environment and preparing the spent nuclear fuel for dry storage, the method comprising: a) providing a cask having both gamma radiation and neutron shielding properties, the cask having a top, a bottom and a cavity having an open top end and a closed bottom end; b) positioning a canister having an open end in the cavity; c) submerging the cask and canister into an underwater environment, the canister filling with water; d) positioning spent nuclear fuel within the canister; e) placing a lid atop the open canister thereby substantially enclosing the open end of the canister; f) raising the cask and canister until the top of the cask is above a water level of the underwater environment while a major portion of the cask remains below the water level; g) removing bulk water from the canister while a portion of the cask remains below the water level; and h) raising the entire cask above the water level of the underwater environment. Referring to FIG. 1, a transfer cask 100, according to one embodiment of the present invention, is illustrated. The transfer cask 100 is generally cylindrical in shape and vertically oriented such that its axis is in a substantially vertical orientation. The shape of the transfer cask 100, however, is not limiting of the invention and can include a multitude of other horizontal cross-sectional shapes, including without limitation square, rectangular, triangular and oval shaped transfer casks. The size, height and orientation of the transfer cask 100 also are not limiting of the invention but will be dictated by safety considerations, the desired load to be accommodated and the facility in which it is to be used. The transfer cask 100, as illustrated, is designed for use with and to accommodate a multi-purpose canister (“MPC”) in effectuating HLW transfer procedures. Preferably, the transfer cask 100 can accommodate no more than one canister, the invention is not so limited, however. An example of one suitable MPC is disclosed in U.S. Pat. No. 5,898,747 to Singh, issued Apr. 27, 1999. The invention, however, is not limited to the use of any specific canister structure. Furthermore, in some embodiments, the inventive concepts discussed herein can be incorporated into and/or utilized by transfer casks (or other containment structures) that do not utilize a canister. For example, the inventive concepts discussed herein can be incorporated into and/or implemented into containment structures, such as metal casks, that have the fuel basket built directly into the storage cavity. For exemplary purposes, the transfer cask 100, and the methods discussed herein, will be described in connection with the transport, preparation and handling of spent nuclear fuel (“SNF”). However, the invention is not so limited and can be utilized to handle, transport and/or prepare any type of HLW, including without limitation burnable poison rod assemblies (“BRA”), thimble plug devices (“TPD”), control rod assemblies (“CRA”), axial power shaping rods (“APSR”), wet annular burnable absorbers (“WABA”), rod cluster control assemblies (“RCCA”), control element assemblies (“CEA”), water displacement guide tube plugs, orifice rod assemblies, vibration suppressor inserts and any other radioactive materials. The transfer cask 100 and its components have a top and bottom. As used herein, “bottom” refers to the end of the transfer cask 100 (or its component) that is closer to the ground than the respective end of the transfer cask 100 (or the component) that is the “top,” when the transfer cask 100 is used in the contemplated vertical orientation of FIG. 1. The terms “top” and “bottom” are not so limited, however, and the transfer cask 100 is not limited to being used in the vertical orientation of FIG. 1. Thus, for example, when the transfer cask 100 is rotated by 90 degrees from the vertical orientation of FIG. 1, the terms “top” and “bottom” refer to ends that are at the same height from the ground, but at opposite ends of the structure and or its components. The transfer cask 100 generally comprises a body 10, a bottom lid 60, a jacket 20 and a top lid 13. The body 10 forms a cavity 6 for receiving SNF. The body 10 functions as a gamma radiation absorbing structure for an SNF load that is located within the cavity 6. The jacket 20 functions to absorb the neutron radiation emanating from the SNF load located within the cavity 6. The jacket 20 circumferentially surrounds a major portion of the height of the body 10 and is adapted to receive a neutron absorbing fluid, such as water, boronated water, or another fluid that is rich in hydrogen. Both the body 10 and the jacket 20 draw the residual heat from the SNF load away from the cavity 6, and eventually removed from the transfer cask 100 via convective cooling forces on the outer surface of the transfer cask 100. As will be described in greater detail below with respect to FIGS. 3 and 4, the jacket 20 is designed to maximize heat removal from the SNF by creating a natural thermosiphon circulation of the neutron absorbing fluid within the jacket 20. The body 10 is positioned atop bottom lid 60. The bottom lid 60 acts as the floor of the cavity 6 formed by the inner surface of the body 10. The bottom lid 60 is constructed so that it adequately serves as a floor portion of the gamma radiation containment boundary, thereby preventing the gamma radiation emanating from the SNF load within the cavity 6 from escaping downward. The bottom lid 60 comprises a plurality of plates in a stacked arrangement. The plates are preferably constructed of steel, lead or another gamma radiation absorbing material. A layer/plate of neutron absorbing material can be implemented into the bottom lid 60 if desired. The bottom lid 60 is connected to the bottom of the body 10. More specifically, the bottom lid 60 is connected to the bottom surface of the bottom flange 12 of the body 10. The bottom lid 60 comprises a plurality of plates that are removable from the body 10 so as to allow transfer of the SNF load out of the bottom of the transfer cask 100 by lowering the SNF through the bottom of the cavity 6. The plates can be connected to the bottom flange 12 via bolts or other hardware. The bottom lid 60 is preferably non-unitary with respect to the body 10, thereby forming a base-to-body interface between the two. O-rings and/or other suitable seals can be implemented to hermetically seal the bottom lid 60 to the body 10. In alternate embodiments, the bottom lid 60 can be integrally formed as part of the body 10 and/or can take on a wide variety of structural detail. For example, the bottom lid 60 can be a thick forging or the like, eliminating the need for a plurality of plates. The top lid 13 is preferably a non-unitary structure with respect to the body 10 so that the top lid 13 can be repetitively secured and unsecured to the body 10 without compromising the structural integrity of the transfer cask 100 and/or the containment boundary. The top lid 13 rests atop a top edge 11 of the body 10 so as to form a lid-to-body interface therebetween. The top edge 11 of the body is formed by the upper surface of an annular ring 115. The top lid 13 is secured to the top edge 11 by extending bolts 63 through holes in the top lid 13 and threadily engaging corresponding bores in the top flange 11. The internal surfaces of the bores are preferably threaded for engagement with the bolts 63. While bolts 63 are illustrated as the connection means, other suitable hardware and connection techniques can be used, including without limitation screws, a tight fit, etc. Referring now to FIGS. 1 and 3 concurrently, the body 10 comprises a first shell 15 and a second shell 16. The body 10 is constructed of gamma radiation absorbing material so as to provide the necessary containment boundary for SNF positioned in the transfer cask 100. While the shells 15, 16 are generally cylindrical in shape, other shapes can be used. For example, the horizontal cross-sectional profiles of the shells 15, 16 can be rectangular, oval, etc. The invention is not limited by the shape of the shells 15, 16. The annular ring 115 is connected to the tops of the shells 15, 16. The annular ring 115 adds structural integrity to the shells 15, 16 and provides a solid structure to which the top lid 13 can be secured. The inner surface 116 of the first shell 15 forms a cavity 6 for receiving and holding a canister of SNF. As mentioned above, if desired, the cavity 6 can be adapted to accommodate SNF directly by incorporating a fuel basket assembly directly therein so as to eliminate the need for a canister. The first shell 15 and the second shell 16 are preferably made from steel because of its gamma radiation absorbing and heat conducting attributes. However, other gamma absorbing materials can be used. The second shell 16 concentrically surrounds the first shell 15 so as to form an annular gap 14 therebetween which is filled with a gamma absorbing material, thereby forming an additional layer of gamma absorbing material. The annular gap 14 can be filled with any gamma absorbing material, including without limitation concrete, lead, steel, etc. or combinations thereof. Preferably, the gamma absorbing material used in the annular gap 14 is a material, such as steel, that can adequately conduct heat radially outward away from the cavity 6 so that residual heat emanating from SNF can be removed. It also possible that the annular gap 14 comprise another shell rather than a filled gap. While the body 10 is illustrated and described as a multilayer structure, the body 10 can be constructed as a unitary structure from a single thick shell or from a combination of concrete and metal, such structural details of the body 10 are not limiting of the invention, so long as the necessary cooling and gamma radiation adsorption are provided by the body 10 for the radioactive load to be positioned in the cavity 6. The top edges of the first and second shells 15, 16 are connected to a bottom surface of the annular ring 115 via welding or other connection technique. Similarly, the bottom edges of the first and second shells 15, 16 are connected to the top surface of the bottom flange 12 of the body 10. The bottom flange 12 is a plate-like structure that contains the necessary holes and hardware for both connecting the plates of the bottom lid 16 to the body 10 and connecting the transfer cask 100 to a mating device during canister transfer operations. Referring solely to FIG. 1, the inner surface 116 of the first shell 15 forms the cavity 6 for receiving the SNF load. The cavity 6 is a cylindrical cavity having an axis that is in a substantially vertical orientation. The invention is not so limited however, and the axis could be in a substantially horizontal orientation or another orientation. The horizontal cross-sectional profile of the cavity 6 is generally circular in shape, but is dependent on the shape of the first shell 15, which is not limited to circular. The top end of the cavity 6 is open, providing access to the cavity 6 from outside of the transfer cask 100 (the top lid 13 provides closure to the top end of the cavity 6 when secured to the transfer cask 100). The bottom end of the cavity 6 is also open, and can be closed by the bottom lid 60. More specifically, the top surface 117 of the bottom lid 60 acts as a floor for the cavity 6. Two trunnions 61 are provided at the top of the body 10. The trunnions 61 provide a means by which a lifting device can engage the transfer cask 100 for lilting and transport. The trunnions 61 are preferably circumferentially spaced from one another about 180° apart and made of a material having high strength and high ductility. The invention is not limited to a trunnion, any means for attaching a lifting device can be used, including without limitation, eye hooks, protrusions, etc. Referring now to FIGS. 1 and 3 concurrently, the transfer cask 100 further comprises a jacket 20. The height of jacket 20 is less than the height of body 10. The jacket 20 is preferably tall enough to cover the height of the SNF stored in the cavity 6. The jacket 20 is formed by a shell 120 which is concentric to and surrounds the second shell 16. The shell 120 can be constructed of steel or other materials, such as metals, alloys, plastics, etc. However, it is preferred that the shell 120 be formed of a good heat conducting material, such as steel. In the illustrated embodiment, the shell 120 is formed by a plurality of panels 22. A total of eight panels 22 are used to form the shell 120. The invention, however, is not so limited and the shell 120 can be a unitary shell or consist of any number of panels 22. The shell 120 has a top edge 125 and a bottom edge 126 (best seen in FIG. 4). The jacket 20 comprises a gap/space 19 formed between the shell 120 and the second shell 16 for receiving a neutron absorbing fluid. The gap 19 is adapted to receive a neutron absorbing fluid, such as boronated water, to provide a layer of neutron shielding for the SNF load within the cavity 6. The second shell 16 acts as the inner wall of the gap 19 while the shell 120 acts as the outer wall of the gap 19. The jacket 20 further comprises bottom ring plate 55 and a top ring plate 56 which form the floor and the roof of the gap 19. The top and bottom ring plates 55, 56 are ring-like plate structures that surround the outer surface 121 of the second shell 16. While the bottom ring plate 55 is a single unitary ring-like structure, the top ring plate 56 is formed of a plurality of sections in stepped manner to accommodate the trunnions 61. Of course, either the top or bottom ring plates 55, 56 can be constructed in either manner. The jacket 20 further comprises one or more fill valves 23 located at or near the top of jacket 20. The fill valve 23 is adapted so as to be capable of being moved between an open position and a closed position. When the fill valve 23 is in a closed position, it is hermetically sealed. When the fill valve 23 is in the open position, it allows for efficient filling of the jacket 20 with a neutron absorbing fluid, such as boronated water or the like. The jacket 20 further comprises one or more drain valves (not illustrated). The drain valves are also adapted so as to have an open and a closed position. When the drain valves are in the open position, they allow for removal of the neutron absorbing fluid from the jacket 20. When the drain valves are in the closed position, they are hermetically sealed. As is best visible in FIG. 4, the bottom and top ring plates 55, 56 are respectively connected to the top and bottom edges, 125,126 of the shell 120 in a hermetic manner. Likewise, the inner edges of the bottom and top ring plates 55, 56 are connected to the outer surface 121 of the shell 16 in a hermetic manner. A proper weld will achieve these hermetic connections. The outer surface 121 of the second shell 16 acts as the inner wall of the gap 19 while the inner surface 122 of the shell 120 acts as the other inner wall of the gap 19. The floor of the gap 19 is formed by the top surface 123 of the bottom ring plate 55. The ceiling of the gap 19 is formed by the bottom surface 124 of the top ring plate 56. The gap 19 is a hermetically sealable space/volume capable of holding a neutron absorbing fluid without leaking. The gap 19, of course, can be other shapes beside annular. Referring now to FIGS. 2 and 3 concurrently, the jacket 20 further comprises a plurality of radial plates 21 positioned within the gap 19. The radial plates 21 are preferably made of steel or another metal or material having good heat conduction properties. Each radial plate 21 comprises a first face 27, a second face 28, an outer lateral edge 25 an inner lateral edge 26, a top edge 24 and a bottom edge 23. The outer lateral edge 25 and inner later edge 26 are vertically oriented. The outer lateral edges 25 of the radial plates 21 are connected to the inner surface 122 of the shell 120 while the inner lateral edges 26 of the radial plates 21 are connected to outer surface 121 of the second shell 16. The radial plates 21 act as fins for improved heat conduction from the body 10, through the jacket 20 and to the atmosphere surrounding the transfer cask 100. In another embodiment, the lateral edges 25, 26 of the radial plates 21 may be radially offset from one another so that a straight line does not exist through the radial plate 21 from the second shell 16 to the jacket 20. For example, the radial plates 21 can be bent so as to have a zig-zag horizontal cross-sectional profile. This prohibits neutron radiation escape through the radial plates 21. The top edge 24 of the radial plate is connected to the bottom surface 124 of the top ring plate 56. The bottom edge 24 of the radial plate 21 is connected to the top edge 123 of the bottom ring plate 55 The radial plates 21 extend radially between the second shell 16 and the shell 120 of the jacket 20, thereby dividing the gap 19 into a plurality of circumferential zones 41A-H. At least one hole 34 (visible in FIG. 4) preferably exists that forms an open passageway between each of the adjacent circumferential zones 41A-H. By providing these holes 34, neutron absorbing fluid can flow freely throughout the entirety of the gap 19 when supplied to a single circumferential zone 41 during the jacket filling procedure. In the illustrated embodiment, the holes 34 are formed by chamfered edges of the radial plates 21. However, the passageways can be provided in any manner desired, for example as a plurality of gaps between the top edge 24 of the radial plate 21 and the top ring plate 56. Referring still to FIGS. 2 and 3, the jacket 20 further comprises a plurality of baffles 40. As will be discussed in further detail below, the baffles 40 facilitate a natural thermosiphon circulation of the neutron absorbing fluid within the gap 19 of the water jacket 20 to assist in heat removal/cooling of the SNF within the cavity 6. The baffles 40 are plate-like structures positioned in the gap 19 in a substantially vertical orientation. The baffles 40 have a top edge 44, a bottom edge 43, a first lateral edge 45 and a second lateral edge 46 (best seen in FIG. 4). The baffles 40 are located between the shell 120 and the second shell 16 in spaced relation from both the shells 120, 16. A single baffle 40 is located within each circumferential zone 41A-41H. The baffles 40 are supported in the gap 19 so that a distance exists between the top and bottom edges of the baffle 40 and the top and bottom ring plates 56, 55 respectively. In other words, the height of baffle 40 is less than the height of the gap 19. The baffles 40 are supported in this floating manner by connecting the lateral edges 45, 46 of the baffles 40 to the first and second faces 27, 28 of the radial plates 21. Welding or other connection techniques could be used. Referring now to FIGS. 3 and 4 concurrently, the structure and functioning of the jacket 20 relative to the thermosiphon circulation within the gap 19 will be discussed in greater detail. The structure and functioning of the jacket 20 relative to the thermosiphon circulation will be discussed in relation to a single circumferential zone 41 with the understanding the principles and structure are applicable to all zones 41A-41H. The baffles 40 comprise a first plate 42 and a second plate 48. The first and second plates 42, 48 are connected to one another along their major surfaces. However, as will be discussed below, this connection is preferably accomplished so that intimate surface contact does not exist between the major surfaces of inner and outer plates 42, 48 of the baffle 40. The inner and outer plates 42, 48 are preferably made of stainless steel. Moreover, while the baffles 40 are illustrated as a plurality of circumferential plates 42, 48 separated by the radial plates 21, a single plate or shell can be used to act as the baffle for the entire gap 19. The baffle 40 is positioned in the gap 19 in radially spaced relation to the outer surface 121 of the second shell 16 and the inner surface 122 of the shell 120. Thus, the baffle 40 divides the gap 19 into an inner region 19A and an outer region 19B. The inner region 19A is that region of space located between the baffle 40 and the outer surface 121 of the second shell 16. The outer region 19B is that region of space located between the baffle 40 and the inner surface 122 of the shell 120. As mentioned above, the height of the baffle 40 is less than the height of the gap 19. As a result, passageways 50, 51 exist between the inner region 19A and the outer region 19B. The passageway 50 is located at or near the top of the gap 19 while the passageway 51 is located at or near the bottom of gap 19. More specifically, the passageway 50 is formed between the top edge of the baffle 40 and a bottom surface 124 of the top ring plate 56. Similarly, the passageway 51 is formed between the bottom edge of the baffle 40 and a top surface 123 of the bottom ring plate 55. The invention is not so limited and passageways 50, 51, could be formed as holes in the baffle 40 itself so long as sufficient fluid passes therethrough between the inner region 19A and the outer region 19B of the gap 19. In such an embodiment, the baffle 40 could be connected to the surface 124 and the surface 123. Holes at or near the top and bottom of baffle 40 could provide the passageways for fluid to flow between the inner and outer regions 19A, 19B. Referring solely to FIG. 4, when SNF is loaded into the cavity 6 of the transfer cask 100, the heat emanating from the SNF conducts radially outward through the body 10. As this heat exits the outer surface 121 of the second shell 16, the heat is absorbed by the neutron absorbing fluid that is located in the inner region 19A of the jacket 20. As the neutron absorbing fluid in the inner region 19A becomes heated, the warmed neutron absorbing fluid rises within the inner region 19A. As a result, cool neutron absorbing fluid from the outer region 19B is draw into the inner region 19A via the passageway 51. The heated neutron absorbing fluid that rose within the inner region 19A is likewise drawn into the outer region 19B via the passageway 50. As the heated neutron absorbing fluid comes into contact with the shell 120, the heat from the neutron absorbing fluid conducts through the shell 120 where it is removed by convective forces on the outer surface 125 of the shell 120. Thus, the neutron absorbing fluid in the outer region 19B cools. As the neutron absorbing fluid cools in the outer region 19B, it flows downward in the outer region 19B until it is adequately cooled and drawn hack into the inner region 19A where the process repeats. It is in this manner in which a natural thermosiphon circulation of the neutron absorbing fluid takes place within the gap 19 of the jacket 20. This natural fluid flow is illustrated by the wavy arrows. In order to promote the thermosiphon flow, it may be preferable that the coefficient of thermal conductivity (K(B)) of the baffle 40 in the radial direction be less than the coefficient of thermal conductivity of the neutron absorbing fluid (K(F)) in the gap 19. Making K(B) less than K(F) may help ensure that the neutron absorbing fluid in the outer region 19B remains cooler than the neutron absorbing fluid in the inner region 19A, thereby maximizing the fluid circulation rate. In one embodiment, this can be achieved by making the baffle 40 of two plates 42, 48 having a gap between the two. Of course, when the baffle 40 or the neutron absorbing fluid is made of a composite, then it is the effective coefficient of thermal conductivity of the baffle 40 that is preferably less than the effective coefficient of thermal conductivity of the neutron absorbing fluid. Referring now to FIG. 5, a shield 200 according to one embodiment of the present invention is illustrated. The shield 200 is a sleeve-like structure that is designed to slidably fit over a containment apparatus, such as transfer cask 100, to provide additional radiation shielding and missile protection. The shield 200 is intended to be placed over a transfer cask once it is in the staging area (i.e. removed from the fuel pond). Although the term “staging area” generally refers to an area in a facility for drying and other preparations of a cask, as used herein, staging area can be any area of a facility including an area where nothing is being preformed to the cask. Although the shield 200 is designed for use with and to accommodate the transfer cask 100, the invention is not limited to the use of any specific transfer cask. It is to be further understood that the shield 200, in and of itself, is a novel device and can constitute an embodiment of the invention independent of the components of the transfer cask 100. The shield 200 comprises a thick shell 220 and a top plate 210. The top plate 210 is a ring-like plate having a central opening 221. The top plate 210 is connected to the top edge of the thick shell 220. The thick shell 220 has an open bottom end thereby forming a bottom opening 225 of the shield 200. The central opening 221 has a smaller diameter than the bottom opening 225. The diameter of the bottom opening 225 is large enough so that the shield 200 to be slid over the top of the transfer cask 100, as will be discussed with reference to FIG. 6. The inner surface 221 of the shell 220 forms an internal cavity 211 for receiving the transfer cask 100. The cavity 211 has a diameter greater than the diameter of transfer cask 100, or the containment apparatus with which the shield 200 is to be used. The shield 200 further comprises a plurality of eye hooks 212 are welded to the top surface of the top plate 210 and are used by a crane to carry the shield 200. The invention is not limited to eye hooks, any means for attaching a transport device may be used, including trunnions and other protrusions. The shell 220 and the top plate 210 are made of a gamma absorbing material, such as steel, lead, etc. The shield 200 can be as thick as required, preferably at least 5 inches thick. In another embodiment, the shield 200 could be a multi-layer structure rather that a single layer structure. The shield 200 further comprises a plurality of spacers 230 located on the inner surface 221 of the shell 220 and the bottom surface 213 the top plate 210. The spacers 230 are generally L-shaped plates that extend radially into the cavity 211 formed by the shell 220. The spacers 230 comprises a horizontal portion 231 and a vertical portion 232. The horizontal portion 231 extends along the along the bottom surface 213 of the top plate 210 for the entire width of the top plate 210. As will be discussed below with reference to FIG. 6, the horizontal portion 231 acts as a flange to support the weight of the shield 200. In an alternative embodiment, the top plate 210 could act as a flange instead of the horizontal portion 231 of the spacers 230. In such an embodiment, the top plate 210 could extend into the cavity 211 rather than connecting solely to the top edge of the shell 230. The horizontal portion 231 extends into the cavity 211 a further distance than does the vertical portion 232. Stated another way, the horizontal portion 23 of the spacer 230 extends from the inner surface 221 of the shell 220 into the cavity 211 by a first distance. The vertical portion 232 of the spacer 230 extends from the inner surface 221 of the shell 220 into the cavity 211 by a second distance. The first distance is greater than the second distance. The vertical portion 232 extends along the inner surface 221 of the shell 220 from the horizontal portion 231 to the bottom of the shield 200. The invention is not so limited, however, and the vertical portion 232 could be segmented or formed from a plurality of pins, bars, etc. Additionally, where the vertical portion 232 is segmented, the segments do not have to be vertically aligned. The spacers 230 are preferably circumferentially spaced from another by about 60° (best seen in FIG. 7), but could comprise more spacers 230 spaced closer together, etc. The spacers 230 are made of a material having high strength and ductility, sufficient so that the horizontal portion 231 is strong enough to support the full weight of the shield 200. Referring to FIG. 6, the shield 200 slidably fits around the transfer cask 100 so as to form a shield-to-transfer cask interface. The shield 200 has a height that is less than the height of the transfer cask 100. As a result, the shield 200 does not extend the full height of transfer cask 100. As will be discussed below, this allows a space to exist between the shield 200 and the ground so that air can circulate under the shield 200 and over the outer surface of the transfer cask 100 when the shield 200 is fitted over the transfer cask 100. The horizontal portion 231 of the spacers 230 acts as a flange and rests on the top surface 56 of the transfer cask 100 while the vertical portion 232 of the spacers 230 contacts the outer surface of the wall of the transfer cask 100. Referring to FIG. 7, the spacers 230 maintain channels 240 between the inner surface of the shell 220 spaced from the outer surface of the transfer cask 100. The spacers 230 divide the gap between the shell 220 and the cask 100 into a plurality of channels 240. The channels 240 allow air to flow between the shield 200 and the transfer cask 100 so as to cool the transfer cask 100 that is heated by the SNF stored in the cavity 6. The channels 240 are not limited to linear passageways and could be formed as tortuous paths from the bottom of the shield 200 to the top of the shield 200. Referring to FIG. 8, air can enter via an opening 241 below the shield 200 and enter into the spaces 240. The air is warmed by heat emanating from the transfer cask 100 and naturally rises within the spaces 240. The warmed air exits the spaces 240 via an exit opening 242 at the top of the shield 200. The wavy arrows indicate this natural thermosiphon/chimney flow. Referring now to FIG. 9, a method of the present invention is illustrated in the form of a flowchart 900. The steps of FIG. 9 will be discussed in relation to the apparatus shown in FIGS. 1-8. In defueling a nuclear reactor and storing the spent nuclear fuel, a transfer cask 100 having cavity 6 and a neutron radiation absorbing jacket 20 surrounding the cavity 6 is provided. Thereby accomplishing step 910. An open multi purpose canister (MPC) is placed in cavity 6 of transfer cask 100, completing step 920. When the embodiment is utilizing a canister and cask, i.e., a dual containment system, the entire structure is thought of as a container having a top, a bottom, and a cavity. The transfer cask 100 with the open MPC is submerged into a fuel pond so that the top of the MPC is below a surface level of the fuel pond. The water from the fuel pond fills the open MPC, thereby completing step 930. When the nuclear fuel is depleted in the nuclear reactor, the spent nuclear fuel is removed from the reactor, lowered into the fuel pond, and placed into the MPC, thereby completing step 940. Once the MPC is fully loaded, a lid is secured to the MPC enclosing the both the spent nuclear fuel and water from the storage pond, completing step 950. A crane or other lifting device is attached to trunnions 61 of transfer cask 100. Once secured to trunnions 61, the crane lifts transfer cask 100, containing the loaded MPC, in an upright orientation toward the water level of the storage pond, completing step 960. The top surface of transfer cask 100 is lifted to be just above the water level so that water from the storage pond can no longer flow into the MPC. Preferably, the top surface of the transfer cask 100 is between 1 to 12 inches above the surface level of the body of water so that a substantial portion of the transfer cask. 100 and MPC remains below the surface level of the water in the fuel pond. Additionally, it is to be understood that rather than raising the transfer cask 100 above the surface level of the fuel pond, the water in the fuel pond could be drained until the top of the MPC is above the lowered surface level of the fuel pond. Stated broadly, step 960 can be achieved by relative movement of the transfer cask 100 and the water the fuel pond. Upon the transfer cask. 100 being just above the water level, bulk water is removed from the MPC, thereby completing step 970. The weight within transfer cask 100 has now been reduced in an amount equal to the weight of bulk water removed. At this stage, the lifting device removes transfer cask 100 containing the MPC from the storage pond and places it onto a staging area, completing step 980. While in the staging area, the empty volume of the MPC is filled with water, completing step 990. A removable radiation shield/skirt 200 is then slidably placed around the transfer cask 100. The shield 200 is positioned above the transfer cask. 100 by using a crane connected to the eye hooks 212. The shield 200 is lowered so that the open bottom end 225 of the shield 200 slides over the transfer cask. 100. The horizontal portion 231 of the spacer 230 contacts an upper surface of the top ring plate 56 and rests thereupon. Cool air then enters into the chamber 240 and rises within the chamber 240 until exiting at the top. This cool air acts to remove heat emitted by the spent nuclear fuel store din transfer cask 100. Step 1000 is now complete. The lid is now welded onto the MPC and the spent nuclear fuel is prepared for long term dry-state storage, thereby completing step 1010. During said drying procedure, the water is drained from the MPC and the MPC is filled with an inert gas. Such filling with gas is well known in the art. The method of the invention can comprise any combination of the steps mentioned above. All of the steps are not necessary to practice the invention. While the invention has been described and illustrated in sufficient detail that those skilled in this art can readily make and use it, various alternatives, modifications, and improvements should become readily apparent without departing from the spirit and scope of the invention.
044255080	claims	1. An electron beam lithographic system for the fabrication of devices having fine geometries, said system comprising: means for forming an electron beam suitable for exposing a photolithographic resist and for scanning said beam over a limited region; a movable plate-like puck including, on one side, means for holding a device to be exposed by said electron beam; first puck locating means providing a first bearing surface for said puck including an annular pressurizable region for supporting said puck by gas pressure and, inwardly of said pressurizable region, evacuable region for scavenging gas escaping from between said puck and said first bearing surface, said means providing said first bearing surface including a central aperture through which said electron beam can expose a device carried by said puck; second puck locating means providing a second bearing surface for the side of said puck opposite said first bearing surface, said second surface also including an annular pressurizable region for maintaining a separation between said second surface and said puck and, inwardly of said pressurizable region, an evacuable region; frame means connecting said first and second puck locating means for holding the respective pressurizable and evacuable regions thereof in fixed alignment; and X-Y drive means for controllably positioning said puck with respect to said electron beam forming means thereby to permit selected portions of a device carried by said puck to be brought within the beam scanning region whereby said puck is precisely positioned between said surfaces without being subjected to distorting forces. means for forming in a vacuum an electron beam suitable for exposing a photolithographic resist and for scanning said beam over a limited region smaller than a semiconductor wafer to be exposed; a movable puck including, on one side, means for holding a semiconductor wafer to be exposed by said beam; first puck locating means providing a first bearing surface for said puck including an annular pressurizable region for supporting said puck by gas pressure and, inwardly of said pressurizable region, evacuable region for removing gas escaping from between said puck and said first bearing surface, said means providing said first bearing surface including a central aperture through which said beam can expose a device carried by said puck; second puck locating means providing a second bearing surface for the side of said puck opposite said first bearing surface, said second surface also including an annular pressurizable region for maintaining a separation between said second surface and said puck and, inwardly of said pressurizable region, an evacuable region; frame means connecting said first and second puck locating means for holding the respective pressurizable and evacuable regions thereof in fixed alignment; and X-Y drive means for controllably positioning said puck with respect to said electron beam forming means thereby to permit selected portions of a semiconductor wafer carried by said puck to be brought within the beam scanning region whereby said puck is precisely positioned between said surfaces without being subjected to distorting forces. means for forming an electron beam suitable for exposing a photolithographic resist and for scanning said beam over a limited region smaller than a semiconductor wafer to be exposed; a movable plate-like puck including, on one side, means for holding a semiconductor wafer to be exposed by said electron beam; first puck locating means providing a first bearing surface smaller than said puck including an annular pressurizable region for supporting said puck by gas injected under pressure through a plurality of ports and, inwardly of said pressurizable region, an evacuable region including at least one annular groove for scavenging gas escaping inwardly from between said puck and said first bearing surface, said means providing said first bearing surface including a central aperture through which said electron beam can expose a device carried by said puck; second puck locating means, similar to said first, providing a second bearing surface for the side of said puck opposite said first bearing surface, said second surface also including an annular pressurizable region for maintaining a separation between said second surface and said puck by gas injected under pressure through a plurality of ports and, inwardly of said pressurizable region, an evacuable region including at least one annular groove for scavenging gas escaping inwardly from said pressurizable region; frame means connecting said first and second puck locating means for holding the respective pressurizable and evacuable regions thereof in fixed alignment; and X-Y drive means for controllably positioning said puck with respect to said electron beam forming means thereby to permit selected portions of a semiconductor wafer carried by said puck to be brought within the beam scanning region whereby said puck is precisely positioned between said surfaces without being subjected to distorting forces. 2. A lithographic system for the fabrication of semiconductor devices; said system comprising: 3. A system as set forth in claim 2 wherein each of said puck locating means includes, around the periphery of the respective bearing surface, a plurality of H-shaped grooves through which gas under pressure may be distributed to create a region of pressure. 4. A system as set forth in claim 3 wherein a metering valve is provided at the cross arm portion of each of said H-shaped grooves. 5. A system as set forth in claim 3 wherein each of said puck locating means includes, inwardly of the H-shaped grooves, an annular groove through which gas, escaping inwardly from the region of pressure, may be scavenged. 6. A system as set forth in claim 3 wherein said second puck locating means includes an evacuable central aperture in alignment with said beam forming means. 7. An electron beam lithographic system for the fabrication of semiconductor devices; said system comprising:
040381331	abstract	A reactor has a core formed by a plurality of laterally adjacent fuel assemblies, each assembly comprising a vertically elongated casing containing a bundle of fuel rods and having an upper end connected to a tubular suspension rod forming the primary suspension means for the casing, failure of this means permitting the fuel assembly to drop from the core. In each instance, an instrumentation tube having an upper end supported independently of the primary suspension rod, extends downwardly through the latter, and centrally through the casing to the lower end of the latter. This instrumentation tube and the fuel assemblies adjacent to each other remain suspended so as to form vertically fixed parts relative to any one assembly that might drop accidentally. Each of the casings have latch means for normally latching the casing to one of these fixed parts so as to each casing it cannot fall substantially relative to that one of the parts in the event of a failure of its tubular suspension rod normally forming its primary suspension.
	claims	1. An imaging system, comprising:a focal spot configured to rotate along a path around an examination region and emits radiation;a collimator configured to collimate the radiation, producing a radiation beam that traverses a field of view of the examination region;a detector array located opposite the radiation source, across the examination region, configured to detect radiation traversing the field of view and produces a signal indicative of the detected radiation; anda beam shaper, located between the radiation source and the collimator, configured to rotate in coordination with the focal spot and defines an intensity profile of the radiation beam,wherein the beam shaper includes a plurality of elongate x-ray absorbing elements arranged parallel to each other along a transverse direction with respect to a direction of the beam, separated from each other by a plurality of material free regions and widths of the plurality of x-ray absorbing elements along the transverse direction increase from a central region of the beam shaper towards end regions of the beam shaper, wherein each width of a corresponding elongate x-ray absorbing element of the plurality of elongate x-ray absorbing elements is uniform in the transverse direction and is defined by a distance along a line perpendicular to a direction from the focal spot to each of the elongate x-ray absorbing elements. 2. The imaging system of claim 1, wherein the widths of the plurality of x-ray absorbing elements increase exponentially with a fan-angle of the radiation beam. 3. The imaging system of claim 1, wherein a center to center distance of pairs of the plurality of x-ray absorbing elements is the same. 4. The imaging system of claim 1, wherein an intensity of the radiation exiting the beam shaper at the end regions of the beam shaper is less than one percent of the radiation impinging on the end regions of the beam shaper. 5. The imaging system of claim 1, wherein an intensity of the radiation exiting the beam shaper at the central region of the beam shaper is about equal to the radiation impinging on the central region of the beam shaper. 6. The imaging system of claim 1, the beam shaper, comprising:at least first and second sub-beam shapers arranged one on top of the other in the path of the radiation beam, wherein at least one of the first and second sub-beam shapers translates with respect to the other of the at least first and second sub-beam shapers. 7. The imaging system of claim 6, wherein translating at least one of the first and second sub-beam shapers with respect to the other of the at least first and second sub-beam shapers changes an output intensity of the beam shaper. 8. The imaging system of claim 7, wherein at least one of the first and second sub-beam shapers translates with respect to the other of the at least first and second sub-beam shapers during scanning, thereby changing the output intensity of the beam shaper as a function of acquisition angle. 9. The imaging system of claim 6, wherein the first or second sub-beam shapers that translates includes two partial beam shapers, wherein each of the partial beam shapers independently translates with respect to the other of the two partial beam shapers. 10. The imaging system of claim 9, wherein only one of the two partial beam shapers translates for a scan. 11. The imaging system of claim 1, wherein the x-ray absorbing elements are focused at the focal spot. 12. A method, comprising:rotating a focal spot and a beam shaper in coordination on a path around an examination region,wherein the beam shaper includes a plurality of elongate x-ray absorbing elements arranged parallel to each other along a transverse direction with respect to a direction of the beam, separated from each other by a plurality of material free regions, and defines an intensity profile of a radiation beam traversing the examination region and widths of the plurality of x-ray absorbing elements along the transverse direction increase from a central region of the beam shaper towards end regions of the beam shaper, wherein each width is defined by a distance along a line perpendicular to a direction from the focal spot to each of the elongate x-ray absorbing elements, wherein each width of a corresponding elongate x-ray absorbing element of the plurality of elongate x-ray absorbing elements is uniform along a length of the corresponding elongate x-ray absorbing element in the direction of the beam; anddetecting radiation emitted by the focal spot that traverses the beam shaper and the examination region a field of view, and illuminates a detector array located opposite the focal spot, and generating an output signal indicative thereof. 13. The method of claim 12, wherein a center to center distance of pairs of the plurality of x-ray absorbing elements is the same. 14. The method of claim 12, wherein the beam shaper includes at least first and second sub-beam shapers arranged one on top of the other in the path of the radiation beam and at least one of the first or second sub-beam shapers is configured to translate with respect to the other of the at least first and second sub-beam shapers, and further comprising:translating the at least one of the first or second sub-beam shapers with respect to the other of the at least first and second sub-beam shapers prior to scanning a subject. 15. The method of claim 14, further comprising:translating the at least one of the first or second sub-beam shapers with respect to the other of the at least first and second sub-beam shapers prior to or while scanning the subject. 16. The method of claim 15, wherein translating the at least one of the first or second sub-beam shapers with respect to the other of the at least first and second sub-beam shapers prior to or while scanning the subject changes the intensity profile of the radiation beam while scanning the subject. 17. A beam shaper of an imaging system, comprising:a plurality of elongate x-ray absorbing elements arranged parallel to each other along a transverse direction with respect to a direction of the beam, separated from each other by a plurality of material free regions, and widths of the plurality of x-ray absorbing elements in the transverse direction increase from a central region of the beam shaper towards end regions of the beam shaper, wherein each width is defined by a distance along a line perpendicular to a direction from the focal spot to each of the elongate x-ray absorbing elements, wherein a first elongate x-ray absorbing element of the plurality of elongate x-ray absorbing elements includes a first width and is located in the central region and a second elongate x-ray absorbing element of the plurality of elongate x-ray absorbing elements includes a second width and is located in one of the end regions and the second width is greater than the first width. 18. The beam shaper of claim 17, wherein a center to center distance of pairs of the plurality of x-ray absorbing elements is the same. 19. The beam shaper of claim 18, wherein the widths increase as a function of a z-direction. 20. The beam shaper of claim 17, wherein the beam shaper is flat in an x-y plane. 21. The beam shaper of claim 17, wherein the beam shaper is curved in an x-y plane.
	summary
	claims	1. A reactor pressure vessel, comprising: a reactor pressure body having a chamber formed therein and a cross-section; upper connecting branches connected to said reactor pressure body; an upper support plate disposed in said reactor pressure body above said upper connecting branches and expanding over said cross-section of said reactor pressure body, said upper support plate dividing said chamber of said reactor pressure body into an upper dome chamber and a lower chamber, said upper support plate having openings formed therein for accommodating control rods and at least one equalization opening formed therein, said equalization opening having a cross section; and a device fitted in said equalization opening for varying said cross section as an inverse function of a temperature in said lower chamber. 2. The reactor pressure vessel according to claim 1 , including core installations disposed in said reactor pressure body, said reactor pressure body having a pressure vessel wall, a space between said pressure vessel wall and said core installations defines an equalization chamber leading to said equalization opening formed in said support plate body, said equalization opening and said equalization chamber forms a bypass between said lower chamber and said upper dome chamber. claim 1 3. The reactor pressure vessel according to claim 1 , wherein said cross section of said equalization opening is passively temperature-controlled. claim 1 4. The reactor pressure vessel according to claim 1 , wherein: said device in an event of a temperature drop enlarges said cross section of said equalization opening by utilizing a thermal contraction of a material of said device, and in an event of a temperature rise said device reduces said cross section of said equalization opening by utilizing a thermal expansion of said material of said device. claim 1 5. The reactor pressure vessel according to claim 4 , wherein said device has an expansion sleeve. claim 4 6. The reactor pressure vessel according to claim 5 , wherein said device has a cylinder and a hollow piston guided in said cylinder, said device further having an expansion sleeve connected to said hollow piston, said hollow piston having end openings and an interior formed therein and said cylinder having cooling openings formed therein, said interior of said hollow piston connected by way of said end openings of said hollow piston to both said lower chamber below said support plate and to said upper dome chamber disposed above said support plate, and said hollow piston has additional lateral openings formed therein which when said expansion sleeve contracts aligns with said cooling openings of said cylinder. claim 5 7. A process for temperature equalization between an upper dome chamber disposed above a lower chamber in a reactor pressure vessel, a support plate occupying a cross section of the reactor pressure vessel above upper connecting branches of the reactor pressure vessel and the supporting plate separating the upper dome chamber from the lower chamber, which comprises the steps of: supplying a flow of a medium between the upper dome chamber and the lower chamber through an equalization opening in the support plate; and using a device fitted in the equalization opening for varying the flow of the medium as an inverse function of a temperature in the lower chamber by varying a cross section of the equalization opening. 8. The process according to claim 7 , which comprises supplying a bypass flow of the medium from the lower chamber, which is a reactor annulus defined by a pressure vessel wall and core installations, into the upper dome chamber through the equalization opening. claim 7 9. The process according to claim 7 , which comprises using a passively temperature-control method for controlling the flow of the medium. claim 7 10. The process according to claim 7 , wherein the flow of the medium is increased owing to a temperature drop when shutting down the reactor pressure vessel. claim 7
047284838	claims	1. In a fuel assembly inspection apparatus, the combination comprising: (a) an elongated fixture mounted in a stationary upright position; (b) upper means mounted to an upper portion of said fixture and lower means mounted adjacent to a lower portion of said fixture, said upper and lower means being disposed outwardly from a side of said fixture for supporting a nuclear fuel assembly therebetween and extending along said side of said fixture; (c) a bottom carriage having a central opening adapted to receive the fuel assembly therethrough when supported between said upper and lower means such that said bottom carriage extends about said fuel assembly, said bottom carriage being connected only to, and extending in cantilever fashion outwardly from, said side of said fixture for generally vertical movement along said side of said fixture and along said fuel assembly extending along said side of said fixture; (d) drive means for selectively moving said bottom carriage; and (e) means disposed on said bottom carriage for measuring the envelope of said fuel assembly when said bottom carriage is moved to and stationed at selected axial positions along said fuel assembly. a proximity sensor mounted on each side of said bottom carriage adjacent a side of said fuel assembly for movement along said adjacent side of said fuel assembly; and power means coupled to each said sensor for stationing said sensor at a home position while said bottom carriage is moving along said fuel assembly and for sweeping said sensor relative to said side of said fuel assembly away from and back to said home position once said carriage is positioned at one of said selected axial positions along said fuel assembly. (a) an elongated fixture mounted in a stationary upright position; (b) upper means mounted to an upper portion of said fixture and lower means mounted adjacent to a lower portion of said fixture, said upper and lower means being disposed outwardly from a side of said fixture for supporting a nuclear fuel assembly therebetween and extending along said side of said fixture; (c) a bottom carriage having a central opening adapted to receive the fuel assembly therethrough when supported between said upper and lower means such that said bottom carriage extends about said fuel assembly, said bottom carriage being connected only to, and extending in cantilever fashion outwardly from, said side of said fixture for generally vertical movement along said side of said fixture and along said fuel assembly extending along said side of said fixture; (d) drive means for selectively moving said bottom carriage; and (e) means disposed on said upper means and said bottom carriage for measuring channel spacing between fuel rods of the fuel assembly. a single-axis positioning platform located on each of a pair of adjacent sides of said fuel assembly; a capacitive probe mounted on each of said platforms for movement along said side of said fuel assembly; and motive means for driving said probe to specified channel locations along said fuel assembly side for taking channel spacing measurements once said bottom carriage is positioned at one of said selected axial positions along said fuel assembly. (a) an elongated fixture mounted in a stationary upright position; (b) upper means mounted to an upper portion of said fixture and lower means mounted adjacent to a lower portion of said fixture, said upper and lower means being disposed outwardly from a side of said fixture for supporting a nuclear fuel assembly therebetween and extending along said side of said fixture; (c) a bottom carriage having a central opening adapted to receive the fuel assembly therethrough when supported between said upper and lower means such that said bottom carriage extends about said fuel assembly, said bottom carriage being connected only to, and extending in cantilever fashion outwardly from, said side of said fixture for generally vertical movement along said side of said fixture and along said fuel assembly extending along said side of said fixture; (d) drive means for selectively moving said bottom carriage; (e) means disposed on said bottom carriage for measuring the envelope of said fuel assembly when said bottom carriage is moved to and stationed at selected axial positions along said fuel assembly; and (f) means disposed on said upper means and bottom carriage for continuously monitoring fixture out-of-straightness and performing correction of the envelope measurement in response thereto. a pair of X-Y axes lasers mounted on one of said upper means and said bottom carriage adjacent said fuel assembly; and a pair of matched X-Y photodetectors mounted on the other of said upper means and said bottom carriage adjacent said fuel assembly, said respective lasers providing straight line references used to excite said corresponding photodetectors and said pairs thereof measuring both translational and rotational motion of said bottom carriage as the same moves up along said fuel assembly for facilitating adjustment of the envelope measurement for any fixture error at each of said axial positions along said fuel assembly. (a) an elongated fixture mounted in a stationary upright position; (b) upper means mounted to an upper portion of said fixture and lower means mounted adjacent to a lower portion of said fixture, said upper and lower means being disposed outwardly from a side of said fixture for supporting a nuclear fuel assembly therebetween and extending along said side of said fixture; (c) a bottom carriage having a central opening adapted to receive the fuel assembly therethrough when supported between said upper and lower means such that said bottom carriage extends about said fuel assembly, said bottom carriage being connected only to, and extending in cantilever fashion outwardly from, said side of said fixture for generally vertical movement along said side of said fixture and along said fuel assembly extending along said side of said fixture; (d) drive means for selectively moving said bottom carriage; and (e) means disposed on said bottom carriage and said fixture for measuring fuel assembly length when said bottom carriage has been moved between bottom and top nozzles of said fuel assembly. a photoswitch mounted on each side of said bottom carriage adjacent a side of said fuel assembly and operable to detect an edge of said respective bottom and top nozzles of said fuel assembly; and means forming an optical scale mounted on said fixture and said bottom carriage for determing the position of said carriage as it moves along said fuel assembly when said each photoswitch detects the respective edges of said respective bottom and top nozzles for deriving the length of said fuel assembly. (a) a support base; (b) an elongated fixture mounted in a stationary upright position upon said base and having track means extending along a front side of said fixture; (c) upper means mounted to an upper portion of said fixture and lower means mounted adjacent to a lower portion of said fixture, said upper and lower means being disposed outwardly from said front side of said fixture for supporting a nuclear fuel assembly therebetween and extending along said front side of said fixture; (d) a bottom carriage having a central opening adapted to receive the fuel assembly therethrough when supported between said upper means and lower means such that said bottom carriage will surround all sides of said fuel assembly, said bottom carriage being connected only to said track means, and extending in cantilever fashion outwardly from said front side, of said fixture above said base for generally vertical movement along said front side of said fixture and along said fuel assembly and toward and away from said base; (e) drive means for selectively moving said bottom carriage; (f) means disposed on said bottom carriage for measuring fuel assembly envelope when said bottom carriage is moved to and stationed at selected axial positions along said fuel assembly; (g) means disposed on said upper means and said bottom carriage for continuously monitoring fixture out-of-straightness and performing correction of the envelope measurement in response thereto; (h) means disposed on said bottom carriage for measuring channel spacing between fuel rods of the fuel assembly; and (i) means disposed on said bottom carriage and said fixture for measuring fuel assembly length when said bottom carriage has been moved between the bottom and top nozzles of the fuel assembly. a single-axis positioning table disposed on each side of said bottom carriage adjacent a side of said fuel assembly; a proximity sensor mounted on each said positioning table for movement along said adjacent side of said fuel assembly; and power means coupled to each said sensor for stationing said sensor at a home position while said bottom carriage is moving along said fuel assembly and for sweeping said sensor relative to said side of said fuel assembly away from and back to said home position once said carriage is positioned at one of said selected axial positions along said fuel assembly. a pair of X-Y axes lasers mounted on one of said upper means and said bottom carriage adjacent said fuel assembly; and a pair of matched X-Y photodetectors mounted on the other of said upper means and said bottom carriage adjacent said fuel assembly, said respective laser providing straight line references used to excite said corresponding photodetectors and said pairs thereof measuring both translational and rotational motion of said bottom carriage as the same moves up along said fuel assembly for facilitating adjustment of the envelope measurement for any fixture error at each of said axial positions along said fuel assembly. a single-axis positioning platform located on each of a pair of adjacent sides of said fuel assembly; a probe housing mounted on each of said platforms for movement along said side of said fuel assembly; and first motive means for driving said probe housing to specified channel locations along said fuel assembly side once said bottom carriage is positioned at one of said selected axial positions along said fuel assembly; a capacitive probe contained in each of said probe housings for movement projecting probe into channel of said fuel assembly; and motive means for driving said probe into specified channels between fuel rods along said fuel assembly side for taking channel spacing measurements. a photoswitch mounted on each side of said bottom carriage adjacent a side of said fuel assembly and operable to detect an edge of said respective bottom and top nozzles of said fuel assembly; and means forming an optical scale mounted on said fixture and said bottom carriage for determining the position of said carriage as it moves along said fuel assembly when said each photoswitch detects the respective edges of said respective bottom and top nozzles for deriving the length of said fuel assembly. 2. The apparatus as recited in claim 1, wherein said enelope measuring means includes; 3. In a fuel assembly inspection apparatus, the combination comprising: 4. The apparatus as recited in claim 3, wherein said channel spacing measuring means includes: 5. In a fuel assembly inspection apparatus, the combination comprising: 6. The apparatus as recited in claim 5, wherein said monitoring and correction performing means includes: 7. In a fuel assembly inspection apparatus, the combination comprising: 8. The apparatus as recited in claim 7, wherein said fuel assembly length measuring means includes: 9. In a fuel assembly inspection apparatus, the combination comprising: 10. The apparatus as recited in claim 9. wherein said envelope measuring means includes: 11. The apparatus as recited in claim 9, wherein said monitoring and correction performing means includes: 12. The apparatus as recited in claim 9, wherein said channel spacing measuring means includes: 13. The apparatus as recited in claim 9, wherein said fuel assembly length measuring means includes: 14. The apparatus as recited in claim 9, wherein said upper means is a top carriage mounted to said track means on said fixture for generally vertical movement therealong toward and away from said base. 15. The apparatus as recited in claim 14, wherein said lower means is a pedestal mounted on said base adjacent said fixture and aligned with said top carriage for supporting a nuclear fuel assembly therebetween.
	summary
055442056	claims	1. Device for checking guiding elements of a guide tube in the upper internals of a pressurized water nuclear reactor arranged underwater in a cavity, said guiding elements being arranged inside said guide tube having a vertical axis in a checking position, and being comprised of guiding openings passing through horizontal plates arranged spaced apart from each other axially of said guide tube and of bores of tubular sleeves with vertical axes, said guiding openings and said bores being aligned along a plurality of vertical axial directions, said device including an inspection rod cluster having a spider assembly for attachment to a handling mast, support elements for inspection probes capable of being moved axially inside said guiding openings and said bores of said guiding elements, said inspection probes each being mounted for rotating movement on one of said support elements, about an axis parallel to the axis of said guide tube, and means for rotating said inspection probes, wherein said inspection rod cluster includes: (a) a cylindrical body having a diameter smaller than a diameter of a central bore of said guide tube; and (b) a plurality of radially extending arms fixed around said cylindrical body in determined angular and axial positions and each having a part remote from said cylindrical body, said part carrying an inspection probe arranged rotatively. (a) arranging, below and in line with said guide tube of said upper internals, an inspection rod cluster including a cylindrical body having a diameter smaller than a diameter of a free central bore of said guide tube and a plurality of radially directed arms fixed around said cylindrical body in determined angular and axial positions, each of said arms carrying a rotary inspection probe; (b) introducing said handling mast through an upper end into said guide tube; (c) connecting one end of said handling mast to said spider assembly below said upper internals; (d) moving said inspection rod cluster upwards inside said guide tube by raising said handling mast; and (e) checking said guiding elements with said inspection probes during upward movement of said inspection rod cluster inside said guide tube. 2. Checking device according to claim 1, further including at least two cylindrical guide bars each fixed to the end of a radially extending arm opposite said cylindrical body, and which is solidly attached to said cylindrical body. 3. Checking device according to claim 1 or 2, wherein each of said inspection probes includes a diode laser and an optical mirror which is mounted rotationally about an axis of the probe parallel to the axis of said cylindrical body, so as to intercept radiation coming from said diode laser and to scan the internal surface of said guiding openings and said bores of said guiding elements of said guide tube with said radiation and to return towards said diode the radiation reflected by the surface of said guiding openings and said bores. 4. Checking device according to claim 3, further including an electronic module fixed to the inside of said cylindrical body and including means for processing signals coming from the diode laser associated with a photodetector. 5. Checking device according to claim 3, wherein said mirror is fixed on a support solidly attached to a first end of a flexible cable, an opposite end of said cable being solidly attached to a drive gear driven in rotation by a reducing gear located inside said cylindrical body. 6. Checking device according to claim 1, wherein a means for stopping said inspection rod cluster at the horizontal plates of said guiding elements is mounted on said cylindrical body. 7. Checking device according to claim 1, wherein said cylindrical body carries, in the vicinity of each of said arms, a spring for positioning against one face of a plate traversed by guide openings, having a part constituting a reference surface for a measurement probe. 8. Device according to claim 2, wherein said inspection rod cluster includes four shorter arms placed substantially at 90.degree. to one another around said cylindrical body, each of said arms carrying one inspection probe, and two pairs of arms of greater length in the radial direction than said shorter arms, arranged in extension of one another on either side of the body of said inspection rod cluster and carrying at their ends two axially directed guide bars. 9. Checking device according to claim 2, wherein said inspection rod cluster includes a plurality of arms of different lengths distributed around said cylindrical body, two pairs of arms of greater length carrying at their ends axially directed guide bars, and the other arms carrying measurement probes. 10. Checking device according to claim 8 or 9, wherein said guide bars have an axial length greater than the distance separating two successive horizontal plates pierced with openings for said guiding elements of said guide tube. 11. Checking device according to claim 1, further including a carriage which can be moved over the bottom of the cavity, carrying a support for said inspection rod cluster in the vertical position and said handling mast carrying at its end means for attachment to said spider assembly. 12. Checking device according to claim 11, wherein said carriage includes a vertically movable head including openings for engagement on centering studs of the lower part of said upper internals, so as to ensure precise positioning of said carriage under said internals in said cavity. 13. Checking device according to claim 11, wherein said carriage carries guide means and displacement means for a set of cables connected to one end of said inspection rod cluster and to a control and command station above said cavity at its other end of said inspection rod cluster. 14. Checking device according to claim 11, wherein said carriage carries cameras for visualizing the bottom of said cavity and the upper part of said inspection rod cluster in a vertical position on said carriage. 15. Method for checking guiding elements of a guide tube in upper internals of a pressurized water nuclear reactor arranged underwater in a cavity, said guiding elements being arranged inside said guide tube having a vertical axis in a checking position, and being comprised of guiding openings passing through horizontal plates spaced apart from each other axially of said guide tube and bores of tubular sleeves with vertical axes, said guiding openings and said bores being aligned along a plurality of vertical axial directions, said device including an inspection rod cluster having a spider assembly for attachment to a handling mast, support elements for inspection probes capable of being moved axially inside said guiding elements of said guide tube, said inspection probes each being mounted for rotational movement on one of said support elements, about an axis parallel to an axis of said guide tube and means for rotating the probes, said method comprising the steps of: 16. Checking method according to claim 15, comprising the step of rotating said inspection rod cluster about the axis of said cylindrical body through a certain angle, below said upper internals between two successive operations of upward movement of said inspection rod cluster inside said guide tube, and of checking inside said guide tube. 17. Checking method according to claim 15 or 16, comprising the steps of checking said guide elements by remote radar measurement.
	claims	1. An X-ray image photographing apparatus having: a photographing portion having an image obtaining portion for obtaining a distribution of X-ray having transmitted through an object, and can mount a grid unit including at least a grid for removing scattered rays from the object; a grid detection system for obtaining information from said grid unit or by using said grid unit, and detecting at least one of presence or absence of the grid, a kind of the grid and presence or absence of replacement of the grid; and a control portion for executing photographing or image processing on the basis of at least the result of the detection by said grid detection system. 2. The apparatus of claim 1 , wherein said control portion having: claim 1 an image-processing system for image-processing and outputting image data collected by said image obtaining portion; and a memory portion preserving therein parameters used in said image processing system; wherein said image processing system selects at least one of said parameters preserved in said memory portion on the basis of at least the result of the detection by said grid detection system and executes image processing. 3. The apparatus of claim 1 , wherein further having: claim 1 an image analyzing portion for effecting determination of a kind of the grid, on the basis of at least the result of the detection by said grid detection system, by analyzing image data obtained by said image obtaining portion with the grid fixed. 4. The apparatus of claim 1 , wherein the detection by said grid detection system is effected when the grid unit is mounted on said photographing portion. claim 1 5. The apparatus of claim 1 , wherein said image obtaining portion has a semiconductor sensor. claim 1 6. The apparatus of claim 1 , wherein said image obtaining portion has a fluorescent material sheet. claim 1 7. The apparatus of claim 1 , wherein said grid detection system has a switch member which effects switching corresponding to a shape of a predetermined region of said grid unit, and at least one of presence or absence of said grid, a kind of the grid and presence or absence of replacement of the grid is detected by the switching of said switch member. claim 1 8. The apparatus of claim 1 , further having: claim 1 an inputting portion by which photographing information as to which portion of the object is photographed is input; wherein said control portion having a judging portion for judging the propriety of the adaptation of the grid on the basis of at least the photographing information input by said inputting portion and the result of the detection by said grid detection system. 9. The apparatus of claim 8 , wherein said control portion further having a grid memory portion preserving therein information of an applicable grid corresponding to the photographing information. claim 8 10. The apparatus of claim 8 , further having a display portion for displaying the result of the judgment of said judging portion. claim 8 11. An X-ray image photographing apparatus having: sensor means for obtaining a distribution of X-ray having transmitted through an object; housing means for housing said sensor means, and can mount a grid unit including at least a grid for removing scattered rays from the object; grid detecting means for obtaining information from said grid unit or by using said grid unit to thereby detect at least one of presence or absence of the grid, a kind of the grid and presence or absence of replacement of the grid; and control means for executing photographing or image processing on the basis of at least the result of the detection by said grid detection means. 12. The apparatus of claim 11 , wherein said control means having: claim 11 image processing means for determining an image processing parameter on the basis of at least the result of the detection by said grid detection means for image data collected by said sensor means and executing image processing. 13. The apparatus of claim 11 , wherein further having: claim 11 image analyzing means for effecting determination of a kind of the grid, on the basis of at least the result of the detection by said grid detection means, by analyzing image data obtained by said sensor means with the grid fixed. 14. The apparatus of claim 11 , wherein the detection by said grid detection means is effected when the grid unit is mounted on said housing means. claim 11 15. The apparatus of claim 11 , wherein said grid detection means having switch means which effects switching correspondingly to a shape of a predetermined region of said grid unit, and at least one of presence or absence of the grid, a kind of the grid and presence or absence of replacement of the grid is detected by the switching of said switch means. claim 11 16. The apparatus of claim 11 , further having: claim 11 input means for inputting photographing information as to which portion of the object is photographed; wherein said control means having judging means for judging the propriety of the adaptation of the grid on the basis of at least the photographing information input by said input means and the result of the detection by said grid detection means. 17. The apparatus of claim 16 , further having display means for displaying the result of the judgment of said judging means. claim 16 18. A grid device for use in an X-ray image photographing apparatus having: a grid; a frame holding said grid; and information providing means provided on said frame, said information providing means being designed to provide information concerning at least one of presence or absence of the grid, a kind of the grid and presence or absence of replacement of the grid to said X-ray image photographing apparatus. 19. The device of claim 18 , wherein said information providing means has a projection for operating a micro switch provided on said X-ray image photographing apparatus. claim 18 20. The device of claim 18 , wherein said grid is made movable relative to said frame. claim 18 21. An X-ray image photographing apparatus having: a photographing portion having an image obtaining portion for obtaining a distribution of X-ray having transmitted through an object, and can mount a grid unit including at least a grid for removing scattered rays from the object; a grid detection system detecting at least one of presence or absence of the grid, a kind of the grid and presence or absence of replacement of the grid; and an image processing system for determining an image processing parameter concerning at least one of gain correction, frequency processing, contrast processing and image compression on the basis of at least the result of the detection by said grid detection system for image data obtained by said image obtaining portion and executing image processing.
039768899	abstract	An X-ray diagnostic apparatus for X-ray exposures, having preset X-ray tube voltage and current values, and a preset exposure time and, more particularly, to an apparatus of this type which includes a plurality of filters in conformance with an exposure program for the X-radiation adapted to be selectively employed in coordination with a particular exposure object.
	abstract	The invention relates to the use of a mixture comprising erbium and praseodymium as a radiation attenuating composition, i.e. as a composition that can attenuate ionizing radiation, in particular X- and gamma-type electromagnetic radiation.
	summary
047529474	claims	1. A primary radiation diaphragm for an X-ray apparatus having an X-ray beam, comprising: at least one pair of diaphragm plates respectively disposed in spaced parallel planes, the plates of each pair having opposite side edges; and means for individually adjusting the position of each of said diaphragm plates with respect to said x-ray beam by moving said plates in said planes in directions opposite to each other to a location along a path movement of sufficient length such that either one of said opposite edges of the plates of each pair can selectively limit said X-ray beam, said means including a central disk having a central rectangular opening therein through which said X-ray beam radiates, and having two slots therein respectively receiving pegs extending from said diaphragm plates, an upper disk disposed above said central disk and having a slot disposed at an angle relative to said slots in said central disk for receiving a pin extending from one of said plates, said upper disk having a central opening co-extensive with said central opening in said central disk, and a lower disk disposed between said central disk and having a slot therein disposed at an angle relative to the slots in said central disk for receiving a pin from the other of said plates, said lower disk having a central opening therein co-extensive with said central opening in said central disk, said upper, central and lower disks being individually rotatable relative to each other and synchronized with each other for moving said plates through said slots for selectively covering portions of said central openings in said disks. 2. The primary radiation diaphragm of claim 1 wherein at least one of said opposite side edges is a straight edge. 3. A primary radiation diaphragm as claimed in claim 1 wherein at least one of said opposite side edges is curved.
	summary
	claims	1. A decay heat removal system operating in conjunction with a pressurized water reactor (PWR) including a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel also containing primary coolant water and a pressurizer integral with or operatively connected with the reactor pressure vessel and configured to control pressure in the reactor pressure vessel, the decay heat removal system comprising:a pressurized passive condenser;a turbine;a pump driven by the turbine and connected to suction water from at least one water source into the reactor pressure vessel; andsteam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. 2. The decay heat removal system of claim 1 further comprising:a common shaft, the pump and the turbine being mounted on the common shaft so that the shaft provides direct mechanical coupling via which the turbine drives the pump. 3. The decay heat removal system of claim 1 wherein the at least one water source includes a refueling water storage tank (RWST) disposed with the PWR in a radiological containment structure. 4. The decay heat removal system of claim 1 wherein the at least one water source includes the pressurized passive condenser. 5. The decay heat removal system of claim 1 wherein the at least one water source includes (1) a refueling water storage tank (RWST) disposed with the PWR in a radiological containment structure and (2) the pressurized passive condenser. 6. The decay heat removal system of claim 1 wherein the steam piping includes a pressurizer power operated relief valve configured to control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer. 7. The decay heat removal system of claim 1 wherein the steam piping includes:a pressurizer block valve configured to activate the decay heat removal system by opening to admit steam from the pressurizer to the turbine;a pressurizer power operated relief valve downstream of the pressurizer block valve and configured to control discharge of steam into the pressurized passive condenser to control pressure in the pressurizer; anda steam turbine control valve downstream of the pressurizer block valve and configured to throttle steam into the turbine. 8. The decay heat removal system of claim 1, wherein the pressurizer comprises an integral pressurizer. 9. The decay heat removal system of claim 1 further comprising:a steam generator configured to heat sink the PWR by flow of secondary coolant water in thermal communication with the primary coolant water; anda pressurizer block valve configured to activate the decay heat removal system in response to a loss of heat sinking by the steam generator by opening to admit steam from the pressurizer to the turbine. 10. The decay heat removal system of claim 9 wherein the steam generator comprises an internal steam generator disposed inside the reactor pressure vessel.
	description	The present application is related to and claims the benefit of the earliest available effective filing date(s) from the following listed application(s) (the “Related Applications”) (e.g., claims earliest available priority dates for other than provisional patent applications or claims benefits under 35 USC §119(e) for provisional patent applications, for any and all parent, grandparent, great-grandparent, etc. applications of the Related Application(s)). For purposes of the USPTO extra-statutory requirements, the present application constitutes a continuation-in-part of United States Patent Application entitled METHOD AND SYSTEM FOR THE THERMOELECTRIC CONVERSION OF NUCLEAR REACTOR GENERATED HEAT, naming RODERICK A. HYDE; MURIEL Y. ISHIKAWA; NATHAN P. MYHRVOLD; JOSHUA C. WALTER; THOMAS WEAVER; VICTORIA Y. H. WOOD AND LOWELL L. WOOD, JR. as inventors, filed Apr. 13, 2009, application Ser. No. 12/386,052, which is currently co-pending, or is an application of which a currently co-pending application is entitled to the benefit of the filing date. For purposes of the USPTO extra-statutory requirements, the present application constitutes a continuation-in-part of United States Patent Application entitled METHOD, SYSTEM, AND APPARATUS FOR THE THERMOELECTRIC CONVERSION OF GAS COOLED NUCLEAR REACTOR GENERATED HEAT, naming RODERICK A. HYDE; MURIEL Y. ISHIKAWA; NATHAN P. MYHRVOLD; JOSHUA C. WALTER; THOMAS WEAVER; LOWELL L. WOOD, JR. AND VICTORIA Y. H. WOOD as inventors, filed Jul. 27, 2009, application Ser. No. 12/460,979, which is currently co-pending, or is an application of which a currently co-pending application is entitled to the benefit of the filing date. The United States Patent Office (USPTO) has published a notice to the effect that the USPTO's computer programs require that patent applicants reference both a serial number and indicate whether an application is a continuation or continuation-in-part. Stephen G. Kunin, Benefit of Prior-Filed Application, USPTO Official Gazette Mar. 18, 2003, available at http://www.uspto.gov/web/offices/com/sol/og/2003/week11/patbene.htm. The present Applicant Entity (hereinafter “Applicant”) has provided above a specific reference to the application(s) from which priority is being claimed as recited by statute. Applicant understands that the statute is unambiguous in its specific reference language and does not require either a serial number or any characterization, such as “continuation” or “continuation-in-part,” for claiming priority to U.S. patent applications. Notwithstanding the foregoing, Applicant understands that the USPTO's computer programs have certain data entry requirements, and hence Applicant is designating the present application as a continuation-in-part of its parent applications as set forth above, but expressly points out that such designations are not to be construed in any way as any type of commentary and/or admission as to whether or not the present application contains any new matter in addition to the matter of its parent application(s). Thermoelectric devices and materials can be utilized to convert heat energy to electric power. Thermoelectric devices are further known to be implemented within a nuclear fission reactor system, so as to convert nuclear fission reactor generated heat to electric power during reactor operation. In one aspect, a method includes but is not limited to thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy and supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system. In addition to the foregoing, other method aspects are described in the claims, drawings, and text forming a part of the present disclosure. In one or more various aspects, related systems include but are not limited to circuitry and/or programming for effecting the herein-referenced method aspects; the circuitry and/or programming can be virtually any combination of hardware, software, and/or firmware configured to effect the herein—referenced method aspects depending upon the design choices of the system designer. In one aspect, a system includes but is not limited to means for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy and means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system. In addition to the foregoing, other system aspects are described in the claims, drawings, and text forming a part of the present disclosure. In one aspect, an apparatus includes but is not limited to at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy and at least one electrical output of the at least one thermoelectric device electrically coupled to at least one operation system of the gas cooled nuclear reactor system for supplying the electrical energy to the at least one operation system of the gas cooled nuclear reactor system. In addition to the foregoing, other system aspects are described in the claims, drawings, and text forming a part of the present disclosure. In addition to the foregoing, various other method and/or system and/or program product aspects are set forth and described in the teachings such as text (e.g., claims and/or detailed description) and/or drawings of the present disclosure. The foregoing is a summary and thus may contain simplifications, generalizations, inclusions, and/or omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is NOT intended to be in any way limiting. Other aspects, features, and advantages of the devices and/or processes and/or other subject matter described herein will become apparent in the teachings set forth herein. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. Referring generally to FIGS. 1 through 6, a system 100 for the thermoelectric conversion of gas cooled nuclear reactor generated heat is described in accordance with the present disclosure. One or more thermoelectric devices 104 (e.g., a junction of two materials with different Seebeck coefficients) may convert heat (e.g., operational heat, decay heat, or residual heat) produced by the gas (e.g. pressurized helium or pressurized carbon dioxide) cooled nuclear reactor 102 of the nuclear reactor system 100 to electrical energy. Then, the electrical output 108 of the thermoelectric device 104 may supply electrical energy to an operation system 106 of the gas cooled nuclear reactor system 100. In embodiments illustrated in FIG. 1, the gas cooled nuclear reactor 102 of the gas cooled nuclear reactor system 100 may include, but is not limited to, a gas cooled thermal spectrum nuclear reactor, a gas cooled fast spectrum nuclear reactor, a gas cooled multi-spectrum nuclear reactor, a gas cooled breeder nuclear reactor, or a gas cooled traveling wave reactor. For example, the heat produced from a gas cooled thermal spectrum nuclear reactor may be thermoelectrically converted to electrical energy via one or more than one thermoelectric device 104. Then, the electrical output 108 of the thermoelectric device 104 may be used to supply electrical energy to an operation system 106 of the gas cooled nuclear reactor system 100. By way of further example, the heat produced from a gas cooled traveling wave nuclear reactor may be thermoelectrically converted to electrical energy via one or more than one thermoelectric device 104. Then, the electrical output 108 of the thermoelectric device 104 may be used to supply electrical energy to an operation system 106 of the nuclear reactor system 100. In an additional embodiment, illustrated in FIG. 1, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a control system 116 of the gas cooled nuclear reactor system 100. For example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a rod control system of the gas cooled nuclear reactor system 100. By way of further example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a valve control system of the gas cooled nuclear reactor system 100. In another embodiment, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a monitoring system 122 of the gas cooled nuclear reactor system 100. For example, the monitoring system of the gas cooled nuclear reactor system 100 may include, but is not limited to, one or more than one thermal monitoring system, pressure monitoring system, or radiation monitoring system. In another embodiment, the electrical output 108 of the thermoelectric device 104 may supply electrical energy to a coolant system 124 (e.g., primary coolant system or secondary coolant system) of the gas cooled nuclear reactor system 100. For example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a coolant pump of a coolant system 124 of the gas cooled nuclear reactor system 100. By way of further example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a coolant pump coupled to the primary coolant loop of the coolant system 124 of the gas cooled nuclear reactor system 100. Further, the electrical output 108 of the thermoelectric device 104 may supply electrical energy to a coolant pump coupled to the secondary coolant loop of the coolant system 124 of the gas cooled nuclear reactor system 100. Additionally, the electrical output 108 of the thermoelectric device 104 may supply electrical energy to a coolant pump of the gas cooled nuclear reactor system 100, wherein the coolant pump circulates or aides in circulating at least one pressurized gas coolant of a coolant system of the gas cooled nuclear reactor system 100. For example, the pressurized gas coolant may include, but is not limited to, helium, super critical carbon dioxide, or nitrogen. In another embodiment, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a shutdown system 134 of the gas cooled nuclear reactor system 100. For example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a shutdown system 134 employed during scheduled shutdown of the gas cooled nuclear reactor system 100. By way of further example, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a shutdown system 134 employed during an emergency shutdown (e.g., SCRAM) of the gas cooled nuclear reactor system 100. Further, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a shutdown system 134 while the shutdown system 134 is in a stand-by mode of operation. In another embodiment, the electrical output 108 of a thermoelectric device 104 may supply electrical energy to a warning system 136 of the gas cooled nuclear reactor system 100. For example, the warning system 136, may include, but is not limited to, a visual warning system (e.g., a computer monitor signal, an LED, an incandescent light) or an audio warning system (e.g., auditory signal transmitted via alarm or digital signal sent to CPU and interpreted as audio signal). By way of further example, the warning system 136 may transmit a warning signal to an observer (e.g., on-site operator/user or off-site authorities). Even further, the warning system may transmit the warning signal wirelessly (e.g., radio wave or sound wave) or by wireline, such as a data transmission line (e.g., copper line or fiber optic cable). In another embodiment, the electrical output 108 of a thermoelectric device 104 may be used to partially drive an operation system 106 of the gas cooled nuclear reactor system 100. For example, the electrical power supplied to an operation system by the electrical output 108 of a thermoelectric device 104 may drive or partially drive the operation system 106 of the gas cooled nuclear reactor system 100. For example, the electrical output 108 of the thermoelectric device 100 may drive or partially drive one or more of the following operation systems 106 of the gas cooled nuclear reactor system 100: the control system 116, the monitoring system 122, the coolant system 124 (e.g., primary coolant system or secondary coolant system), the shutdown system 134, or the warning system 136. By way of further example, the electrical energy supplied to a coolant pump of a coolant system 124 of the gas cooled nuclear reactor system 100 may drive or partially drive the coolant pump. For instance, the electrical energy supplied to a coolant pump coupled to the primary coolant loop of the gas cooled nuclear reactor system 100 may drive or partially drive the coolant pump coupled to the primary coolant loop. In another instance, the electrical energy supplied to a coolant pump coupled to the secondary coolant loop of the gas cooled nuclear reactor system 100 may drive or partially drive the coolant pump coupled to the secondary coolant loop. In an embodiment, gas cooled nuclear reactor generated heat may be converted to electrical energy via a thermoelectric device 104 placed in thermal communication (e.g., placed in thermal communication ex-situ or in-situ) with a portion of the gas cooled nuclear reactor system 100. For example, the thermoelectric device 104 may be placed in thermal communication with a portion of the gas cooled nuclear reactor system 100 during the construction of the gas cooled nuclear reactor system 100. By way of further example, the gas cooled nuclear reactor system 100 may be retrofitted such that a thermoelectric device 104 may be placed in thermal communication with a portion of the gas cooled nuclear reactor system 100. Further, the thermoelectric device 104 may be placed in thermal communication with a portion of the gas cooled nuclear reactor system 100 during operation of the gas cooled nuclear reactor system 100 via a means of actuation (e.g., thermal expansion, electromechanical actuation, piezoelectric actuation, mechanical actuation). Then, a thermoelectric device 104 in thermal communication with a portion of the gas cooled nuclear reactor system 100 may convert gas cooled nuclear reactor generated heat to electrical energy. In another embodiment, illustrated in FIG. 2, gas cooled nuclear reactor generated heat may be converted to electrical energy via a thermoelectric device 104 having a first portion 202 in thermal communication with a first portion 204 of the gas cooled nuclear reactor system 100 and a second portion 206 in thermal communication with a second portion 208 of the nuclear reactor system 100. For example, the first portion 202 of the thermoelectric device 104 may be in thermal communication with a heat source 210 of the gas cooled nuclear reactor system. By way of further example, the heat source 210 may include, but is not limited to, a nuclear reactor core, a pressure vessel, a containment vessel, a coolant loop, a coolant pipe, a heat exchanger, or a coolant (e.g., coolant of the primary coolant loop of the gas cooled nuclear reactor system 100). In a further embodiment, the second portion 208 of the gas cooled nuclear reactor system may be at a lower temperature 225 than the first portion 204 of the gas cooled nuclear reactor system 100. For example, the first portion 204 of the gas cooled nuclear reactor system 100 may comprise a portion of the primary coolant system (e.g., at a temperature above 300° C.) of the gas cooled nuclear reactor system 100 and the second portion 208 of the nuclear reactor system 100 may comprise a portion of a condensing loop (e.g., at a temperature below 75° C.) of the gas cooled nuclear reactor system 100. By way of further example, the second portion 208 of the gas cooled nuclear reactor system 100 may include, but is not limited to, a coolant loop, a coolant pipe, a heat exchanger, a coolant (e.g., coolant of the secondary coolant loop of the gas cooled nuclear reactor 100), or an environmental reservoir (e.g., a lake, a river, or a subterranean structure). For instance, a first portion 202 of a thermoelectric device 104 may be in thermal communication with a heat exchanger of the gas cooled nuclear reactor system 100 and the second portion 206 of the thermoelectric device 104 may be in thermal communication with an environmental reservoir (e.g., a lake, a river, a subterranean structure, or the atmosphere). In another instance, a first portion 202 of a thermoelectric device 104 may be in thermal communication with the coolant of the primary coolant loop of the gas cooled nuclear reactor system 100 and the second portion 206 of the thermoelectric device 104 may be in thermal communication with the coolant of the secondary coolant loop of the gas cooled nuclear reactor system 100. In another embodiment, the thermoelectric device 104 and a portion of the gas cooled nuclear reactor system 100 may both be in thermal communication with a means for optimizing thermal conduction 236 (e.g., thermal paste, thermal glue, thermal cement, or other highly thermally conductive materials) between the thermoelectric device 104 and the portion of the gas cooled nuclear reactor system 100. For example, the first portion 202 of the thermoelectric device 104 may be contacted to the first portion 204 of the gas cooled nuclear reactor system 100 using thermal cement. Further, the second portion 206 of the thermoelectric device 104 may be contacted to the first portion 208 of the gas cooled nuclear reactor system 100 using thermal cement. In an embodiment, the thermoelectric device 104 used to convert gas cooled nuclear reactor generated 102 heat to electrical energy may comprise at least one thermoelectric junction 238 (e.g., a thermocouple or other device formed from a junction of more than one material each with different Seebeck coefficients). For example, the thermoelectric junction 238 may include, but is not limited to, a semiconductor-semiconductor junction (e.g., p-type/p-type junction or n-type/n-type junction) or a metal-metal junction (e.g., copper-constantan). By further example, the semiconductor-semiconductor junction may include a p-type/n-type semiconductor junction (e.g., p-doped bismuth telluride/n-doped bismuth telluride junction, p-doped lead telluride/n-doped lead telluride junction, or p-doped silicon germanium/n-doped silicon germanium junction). In another embodiment, the thermoelectric device 104 used to convert gas cooled nuclear reactor 102 generated heat to electrical energy may comprise at least one nanofabricated thermoelectric device 246 (i.e., a device wherein the thermoelectric effect is enhanced due to nanoscale manipulation of its constituent materials). For example, the nanofabricated device 246 may include, but is not limited to, a device constructed in part from a quantum dot material (e.g., PbSeTe), a nanowire material (e.g., Si), or a superlattice material (e.g., Bi2Te3/Sb2Te3). In another embodiment, the thermoelectric device 104 used to convert gas cooled nuclear reactor 102 generated heat to electrical energy may comprise a thermoelectric device optimized for a specified range of operating characteristics 248. For example, the thermoelectric device optimized for a specified range of operating characteristics 248 may include, but is not limited to, a thermoelectric device having an output efficiency optimized for a specified range of temperature. For instance, the thermoelectric device 104 may include a thermoelectric device with a maximum efficiency between approximately 200° and 500° C., such as a thermoelectric device comprised of thallium doped lead telluride. It will be appreciated in light of the description provided herein that a gas cooled nuclear reactor system 100 incorporating a thermoelectric device 104 may incorporate a thermoelectric device having maximum output efficiency within the operating temperature range of the gas cooled nuclear reactor system 100. In another embodiment, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device optimized for a first range of operating characteristics and a second thermoelectric device optimized for a second range of operating characteristics 250. For example, the output efficiency of a first thermoelectric device may be optimized for a first range in temperature and the output efficiency of a second thermoelectric device may be optimized for a second range in temperature. For instance, the gas cooled nuclear reactor generated heat may be converted to electrical energy using a first thermoelectric device having a maximum efficiency between approximately 500° and 600° C. and a second thermoelectric device having a maximum efficiency between approximately 400° and 500° C. In a further embodiment, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device optimized for a first range of operating characteristics, a second thermoelectric device optimized for a second range of operating characteristics, and up to and including a Nth device optimized for a Nth range of operating characteristics. For instance, the nuclear reactor generated heat may be converted to electrical energy using a first thermoelectric device with a maximum efficiency between approximately 200° and 300° C., a second thermoelectric device with a maximum efficiency between approximately 400° and 500° C., and a third thermoelectric device with a maximum efficiency between approximately 500° and 600° C. In an embodiment, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using one or more than one thermoelectric device sized to meet a selected operational requirement 252 of the gas cooled nuclear reactor system 100. For example, the thermoelectric device may be sized to partially match the heat rejection of the thermoelectric device with a portion of the heat produced by the gas cooled nuclear reactor system 100. For instance, the thermoelectric device may be sized by adding or subtracting the number of thermoelectric junctions 238 used in the thermoelectric device 104. By way of further example, the thermoelectric device may be sized to match the power requirements of a selected operation system 106. For instance, the thermoelectric device may be sized to match in full or in part the power requirements of one or more than one of the following gas cooled nuclear reactor 100 operation systems 106: a coolant system 124, a control system 116, a shutdown system 134, a monitoring system 122, or a warning system 136. In another embodiment, illustrated in FIG. 3, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using two or more series coupled thermoelectric devices 104. For example, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device S1 and a second thermoelectric device S2, where the first thermoelectric device S1 and the second thermoelectric device S2 are electrically coupled in series. By way of further example, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device S1, a second thermoelectric device S2, a third thermoelectric device S3, and up to and including an Nth thermoelectric device SN, where the first thermoelectric device S1, the second thermoelectric device S2, the third thermoelectric device S3, and the Nth thermoelectric device SN are electrically coupled in series. In another embodiment, illustrated in FIG. 4, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using two or more parallel coupled thermoelectric devices 104. For example, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device P1 and a second thermoelectric device P2, where the first thermoelectric device P1 and the second thermoelectric device P2 are electrically coupled in parallel. By way of further example, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using a first thermoelectric device P1, a second thermoelectric device P2, a third thermoelectric device P3, and up to and including an Nth thermoelectric device PN, where the first thermoelectric device P1, the second thermoelectric device P2, the third thermoelectric device P3, and the Nth thermoelectric device PN are electrically coupled in parallel. In another embodiment, illustrated in FIG. 5, the heat generated by the gas cooled nuclear reactor 102 may be converted to electrical energy using one or more than one thermoelectric module 502. For example, a thermoelectric module in thermal communication with the gas cooled nuclear reactor system 100 (e.g., the first portion of a thermoelectric module in thermal communication with a heat source 210 and the second portion of a thermoelectric module in thermal communication with an environmental reservoir 234) may convert gas cooled nuclear reactor generated heat to electrical energy. For example, the thermoelectric module 502 may comprise a prefabricated network of parallel coupled thermoelectric devices, series coupled thermoelectric devices, and combinations of parallel coupled and series coupled thermoelectric devices. By way of further example, a thermoelectric module 502 may include a first set of parallel coupled thermoelectric devices, a second set of parallel coupled thermoelectric devices, and up to and including a Mth set of parallel coupled thermoelectric devices, where the first set of devices, the second set of devices, and the Mth set of devices are electrically coupled in series. By way of further example, a thermoelectric module 502 may include a first set of series coupled thermoelectric devices, a second set of series coupled thermoelectric devices, and up to and including a Mth set of series coupled thermoelectric devices, where the first set of devices, the second set of devices, and the Mth set of devices are electrically coupled in parallel. In certain embodiments, as illustrated in FIG. 6, the thermoelectric device 104 used to convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy may be protected via regulation circuitry 602, such as voltage regulation circuitry (e.g., voltage regulator), current limiting circuitry (e.g., blocking diode or fuse), or bypass circuitry (e.g., bypass diode or active bypass circuitry). For example, the regulation circuitry 602 used to protect the thermoelectric device 104 may include a fuse, wherein the fuse is used to limit current from passing through a short-circuited portion of a set of two or more thermoelectric devices 104. In a further embodiment, bypass circuitry configured to actively electrically bypass one or more than one thermoelectric device 104 may be used to protect one or more than one thermoelectric device 104. For example, the bypass circuitry configured to actively electrically bypass a thermoelectric device 104 may include, but is not limited to, an electromagnetic relay system, a solid state relay system, a transistor, or a microprocessor controlled relay system. By way of further example, the microprocessor controlled relay system used to electrically bypass a thermoelectric device 104 may be responsive to an external parameter (e.g., signal from an operator) or an internal parameter (e.g., amount of current flowing through a specified thermoelectric device). In another embodiment, one or more than one thermoelectric device 104 used to convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy may be augmented by one or more than one reserve thermoelectric device 620 (e.g., a thermoelectric junction or a thermoelectric module) and reserve actuation circuitry 622. For example, the electrical output 108 of one or more than one thermoelectric device 104 may be augmented using the output of one or more than one reserve thermoelectric device 620, where the one or more than one reserve thermoelectric device may be selectively coupled to one or more than one thermoelectric device 104 using reserve actuation circuitry 622. By way of further example, in the event a first thermoelectric device 104 of a set of thermoelectric devices fails, a reserve thermoelectric device 620 may be coupled to the set of thermoelectric devices in order to augment the output of the set of thermoelectric devices. By way of further example, the reserve actuation circuitry 622 used to selectively couple the one or more than one reserve thermoelectric device 620 with the one or more than one thermoelectric device 104 may include, but is not limited to, a relay system, an electromagnetic relay system, a solid state relay system, a transistor, a microprocessor controlled relay system, a microprocessor controlled relay system programmed to respond to an external parameter (e.g., required electrical power output of nuclear reactor system 100 or availability of external electric grid power), or a microprocessor controlled relay system programmed to respond to an internal parameter (e.g., output of one or more than one thermoelectric device 104). In another embodiment, the electrical output 108 of one or more than one thermoelectric device 104 used to convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy may be modified using power management circuitry 638. For example, the power management circuitry 638 used to modify the electrical output 108 of a thermoelectric device 104 may include, but is not limited to, a power converter, voltage converter (e.g., a DC-DC converter or a DC-AC inverter), or voltage regulation circuitry. By way of further example, the voltage regulation circuitry used to modify the electrical output 108 of a thermoelectric device 104 may include, but is not limited to, a Zener diode, a series voltage regulator, a shunt regulator, a fixed voltage regulator or an adjustable voltage regulator. Following are a series of flowcharts depicting implementations. For ease of understanding, the flowcharts are organized such that the initial flowcharts present implementations via an example implementation and thereafter the following flowcharts present alternate implementations and/or expansions of the initial flowchart(s) as either sub-component operations or additional component operations building on one or more earlier-presented flowcharts. Those having skill in the art will appreciate that the style of presentation utilized herein (e.g., beginning with a presentation of a flowchart(s) presenting an example implementation and thereafter providing additions to and/or further details in subsequent flowcharts) generally allows for a rapid and easy understanding of the various process implementations. In addition, those skilled in the art will further appreciate that the style of presentation used herein also lends itself well to modular and/or object-oriented program design paradigms. FIG. 7 illustrates an operational flow 700 representing example operations related to the thermoelectric conversion of gas cooled nuclear reactor generated heat to electrical energy. In FIG. 7 and in following figures that include various examples of operational flows, discussion and explanation may be provided with respect to the above-described examples of FIGS. 1 through 6, and/or with respect to other examples and contexts. However, it should be understood that the operational flows may be executed in a number of other environments and contexts, and/or in modified versions of FIGS. 1 through 6. Also, although the various operational flows are presented in the sequence(s) illustrated, it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. After a start operation, the operational flow 700 moves to a converting operation 710. Operation 710 depicts thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat produced by a gas cooled nuclear reactor system 100 to electrical energy. Then, supplying operation 720 depicts supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to an operation system 106 of the gas cooled nuclear reactor system 100. FIG. 8 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 8 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 802, an operation 804, and/or an operation 806. At operation 802, gas cooled nuclear reactor generated operational heat may be thermoelectrically converted to electrical energy. For example, as shown in FIGS. 1 through 6, a thermoelectric device 104 may convert operational heat produced by the gas cooled nuclear reactor system 100 to electrical energy. At operation 804, gas cooled nuclear reactor generated decay heat may be thermoelectrically converted to electrical energy. For example, as shown in FIGS. 1 through 6, a thermoelectric device 104 may convert radioactive decay heat produced by the gas cooled nuclear reactor system 100 to electrical energy. At operation 806, gas cooled nuclear reactor generated residual heat may be thermoelectrically converted to electrical energy. For example, as shown in FIGS. 1 through 6, a thermoelectric device 104 may convert residual heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 9 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 9 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 902, an operation 904, an operation 906, and/or an operation 908. At operation 902, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least one thermoelectric device. For example, as shown in FIGS. 1 through 6, a thermoelectric device 104 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 904 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric junction. For example, as shown in FIG. 2, the thermoelectric device may comprise a thermoelectric junction 238 (e.g., thermocouple). For instance, a thermoelectric junction 238 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 906 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one semiconductor—semiconductor junction. For example, as shown in FIG. 2, the thermoelectric device 104 may comprise a semiconductor-semiconductor thermoelectric junction 240 (e.g., p-type/p-type junction of different semiconductor materials). For instance, a semiconductor-semiconductor thermoelectric junction 238 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 908 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one p-type/n-type junction. For example, as shown in FIG. 2, the thermoelectric device 104 may comprise a p-type/n-type semiconductor junction 242 (e.g., p-doped bismuth telluride/n-doped bismuth telluride junction). For instance, a p-type/n-type semiconductor junction 242 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 10 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 10 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1002. Further, at operation 1002, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least one metal-metal junction. For example, as shown in FIG. 2, the thermoelectric device 104 may comprise a metal-metal thermoelectric junction 244 (e.g., copper-constantan junction). For instance, a metal-metal thermoelectric junction 244 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 11 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 11 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1102, and/or an operation 1104. Further, at operation 1102, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least one nanofabricated thermoelectric device. For example, as shown in FIG. 2, the thermoelectric device 104 may comprise a nanofabricated thermoelectric device 246 (e.g., thermoelectric device constructed partially from a nanowire material, a super lattice material, or a quantum dot material). For instance, a nanofabricated thermoelectric device 246 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, at operation 1104, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least one thermoelectric device optimized for a specified range of operating characteristics. For example, as shown in FIG. 2, the thermoelectric device 104 may comprise a thermoelectric device optimized for a specified range of operating characteristics 248 (e.g., range of temperature or range of pressure). For instance, a thermoelectric device optimized for a specified range of operating characteristics 248 placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 12 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 12 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1202. Further, at operation 1202, gas cooled nuclear reactor generated heat may be converted to electrical energy using a first thermoelectric device optimized for a first range of operating characteristics and at least one additional thermoelectric device optimized for a second range of operating characteristics, the second range of operating characteristics different from the first range of operating characteristics. For example, as shown in FIG. 2, a first thermoelectric device optimized for a first range of operating characteristics and a second thermoelectric device optimized for a second range of operating characteristics 250, wherein the first range of operating characteristics is different from the second range of operating characteristics, may both be placed in thermal communication with the gas cooled nuclear reactor system 100. Then, the first thermoelectric device and the second thermoelectric device 250 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 13 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 13 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1302, an operation 1304, and/or an operation 1306. Further, operation 1302 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear fission reactor system. For example, as shown in FIG. 2, a thermoelectric device 104 sized to meet an operational requirement 252 (e.g., electric power demand) of the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 1304 illustrates thermoelectrically converting nuclear reactor generated heat to electrical energy using at least one thermoelectric device sized to at least partially match the heat rejection of the at least one thermoelectric device with at least a portion of the heat produced by the gas cooled nuclear reactor. For example, as shown in FIG. 2, a thermoelectric device 104 sized to match the heat rejection 254 of the thermoelectric device with the heat produced by the gas cooled nuclear reactor 102 of the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 1306 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device sized to at least partially match the power requirements of at least one selected operation system. For example, as shown in FIG. 2, a thermoelectric device 104 sized to match the power requirements of a selected operation system 256 (e.g., match the power requirements of a coolant system, a control system, a shutdown system, a monitoring system, a warning system or a security system) of the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 14 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 14 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1402, an operation 1404, and/or an operation 1406. Further, the operation 1402 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system. For example, as shown in FIG. 2, a first portion 202 of a thermoelectric device 104 may be in thermal communication with a first portion 204 of a gas cooled nuclear reactor system 100, while a second portion 206 of the thermoelectric device 104 may be in thermal communication with a second portion 208 of the gas cooled nuclear reactor system. Then, the thermoelectric device 104 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 1404 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with at least one heat source of the gas cooled nuclear reactor system. For example, as shown in FIG. 2, the first portion 204 of the gas cooled nuclear reactor system may comprise a heat source 210 of the gas cooled nuclear reactor system 100. Therefore, a first portion of a thermoelectric device 202 may be in thermal communication with a heat source 210 of the nuclear reactor system 100. Then, the thermoelectric device 104 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 1406 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with at least a portion of a nuclear reactor core, at least a portion of at least one pressure vessel, at least a portion of at least one containment vessel, at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, or at least a portion of a coolant of the gas cooled nuclear reactor system. For example, as shown in FIG. 2, the first portion 204 of the gas cooled nuclear reactor system 100 may include, but is not limited to, a nuclear reactor core 212, a pressure vessel 214 of the gas cooled nuclear reactor system 100, a containment vessel 216 of the gas cooled nuclear reactor system 100, a coolant loop 218 of the gas cooled nuclear reactor system 100, a coolant pipe 220 of the gas cooled nuclear reactor system, a heat exchanger 222 of the gas cooled nuclear reactor system 100 or the coolant 224 of the gas cooled nuclear reactor system 100. By way of further example, a first portion of a thermoelectric device 202 may be in thermal communication with a coolant loop 218 of the nuclear reactor system 100. Then, the thermoelectric device 104 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 15 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 15 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1502, and/or an operation 1504. Further, the operation 1502 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device, the thermoelectric device having at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, the second portion of the gas cooled nuclear reactor system at a lower temperature than the first portion of the gas cooled nuclear reactor system. For example, as shown in FIG. 2, a second portion 206 of a thermoelectric device 104 may be in thermal communication with a second portion 208 of a gas cooled nuclear reactor system 100, where the second portion 208 of the gas cooled nuclear reactor system 100 is at a lower temperature than the first portion 204 of the gas cooled nuclear reactor system 100. Then, the thermoelectric device 104 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, the operation 1504 illustrates thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy using at least one thermoelectric device, the thermoelectric device having at least a second portion in thermal communication with at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, at least a portion of a coolant of the gas cooled nuclear reactor system, or at least a portion of at least one environmental reservoir. For example, as shown in FIG. 2, the second portion 208 of the gas cooled nuclear reactor system 100, which is at a temperature lower than the first portion 204 of the gas cooled nuclear reactor system, may include, but is not limited to, a coolant loop 226 of the gas cooled nuclear reactor system 100, a coolant pipe 228 of the gas cooled nuclear reactor system 100, a heat exchanger 230 of the gas cooled nuclear reactor system 100, coolant 232 of the gas cooled nuclear reactor system 100, or an environmental reservoir 234 (e.g., body of water, subterranean structure, or the atmosphere). By way of further example, the second portion 206 of a thermoelectric device 104 may be in thermal communication with a coolant pipe 228 of the gas cooled nuclear reactor system 100, where the coolant pipe 228 is at a temperature lower than the first portion of the gas cooled nuclear reactor system 204. Then, the thermoelectric device 104 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. FIG. 16 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 16 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1602, an operation 1604, and/or an operation 1606. At operation 1602, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least two series coupled thermoelectric devices. For example, as shown in FIG. 3, a first thermoelectric device S1 electrically coupled in series to a second thermoelectric device S2 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, a first thermoelectric device S1, a second thermoelectric device S2, a third thermoelectric device S3, and up to and including a Nth thermoelectric device SN may be used to convert gas cooled nuclear reactor generated heat to electric energy, wherein the first thermoelectric device S1, the second thermoelectric device S2, the third thermoelectric device S3, and up to and including the Nth thermoelectric device SN are series coupled. At operation 1604, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least two parallel coupled thermoelectric devices. For example, as shown in FIG. 4, a first thermoelectric device P1 electrically coupled in parallel to a second thermoelectric device P2 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. Further, a first thermoelectric device P1, a second thermoelectric device P2, a third thermoelectric device P3, and up to and including a Nth thermoelectric device PN may be used to convert gas cooled nuclear reactor generated heat to electric energy, where the first thermoelectric device P1 the second thermoelectric device P2, the third thermoelectric device P3, and up to and including the Nth thermoelectric device PN are parallel coupled. At operation 1606, gas cooled nuclear reactor generated heat may be converted to electrical energy using at least one thermoelectric module. For example, as shown in FIG. 5, a thermoelectric module 502 (e.g., a thermopile or multiple thermopiles) placed in thermal communication with the gas cooled nuclear reactor system 100 may convert heat produced by the gas cooled nuclear reactor system 100 to electrical energy. For example, a thermoelectric module 502 may comprise a prefabricated network of a number of series coupled thermoelectric devices, a number of parallel coupled thermoelectric devices, or combinations of parallel coupled thermoelectric devices and series coupled thermoelectric devices. FIG. 17 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 17 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1702, an operation 1704, and/or an operation 1706. At operation 1702, gas cooled thermal spectrum nuclear reactor generated heat may be thermoelectrically converted to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat generated by a gas cooled thermal spectrum nuclear reactor 110 of a gas cooled nuclear reactor system 100 to electrical energy. At operation 1704, gas cooled fast spectrum nuclear reactor generated heat may be thermoelectrically converted to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat generated by a gas cooled fast spectrum nuclear reactor 111 of a gas cooled nuclear reactor system 100 to electrical energy. At operation 1706, gas cooled multi-spectrum nuclear reactor generated heat may be thermoelectrically converted to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat generated by a gas cooled multi-spectrum nuclear reactor 112 of a gas cooled nuclear reactor system 100 to electrical energy. FIG. 18 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 18 illustrates example embodiments where the converting operation 710 may include at least one additional operation. Additional operations may include an operation 1802, and/or an operation 1804. At operation 1802, gas cooled breeder nuclear reactor generated heat may be thermoelectrically converted to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat generated by a gas cooled breeder nuclear reactor 113 of a gas cooled nuclear reactor system 100 to electrical energy. At operation 1804, gas cooled traveling wave nuclear reactor generated heat may be thermoelectrically converted to electrical energy. For example, as shown in FIG. 1, a thermoelectric device 104 may convert heat generated by a gas cooled traveling wave nuclear reactor 114 of a gas cooled nuclear reactor system 100 to electrical energy. FIG. 19 illustrates an operational flow 1900 representing example operations related to the thermoelectric conversion of gas cooled nuclear reactor generated heat to electrical energy. FIG. 19 illustrates an example embodiment where the example operational flow 700 of FIG. 7 may include at least one additional operation. Additional operations may include an operation 1910. After a start operation, a converting operation 710, and a supplying operation 720, the operational flow 1900 moves to an optimizing operation 1910. Operation 1910 illustrates substantially optimizing a thermal conduction between a portion of at least one gas cooled nuclear reactor system and a portion of at least one thermoelectric device. For example, as shown in FIG. 2, at the position of thermal communication between the thermoelectric device 104 and the gas cooled nuclear reactor system 100, the thermal conduction between the thermoelectric device 104 and the gas cooled nuclear reactor system 100 may be optimized. For example, the thermal conduction optimization 236 may include, but is not limited to, placing thermal paste, thermal glue, or a highly thermal conductive material between the thermoelectric device 104 and the nuclear reactor system 100. FIG. 20 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 20 illustrates example embodiments where the supplying operation 720 may include at least one additional operation. Additional operations may include an operation 2002, an operation 2004, and/or an operation 2006. The operation 2002 illustrates supplying the electrical energy to at least one control system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a control system 116 of a gas cooled nuclear reactor system 100. Further, the operation 2004 illustrates supplying the electrical energy to at least one rod control system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the control system 116 may comprise, but is not limited to, a rod control system 118. For instance, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a rod control system 118 of a gas cooled nuclear reactor system 100. Further, the operation 2006 illustrates supplying the electrical energy to at least one rod control system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the control system 116 may comprise, but is not limited to, a valve control system 120. For instance, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a valve control system 118 of a gas cooled nuclear reactor system 100. FIG. 21 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 21 illustrates example embodiments where the supplying operation 720 may include at least one additional operation. Additional operations may include an operation 2102. The operation 2102 illustrates supplying the electrical energy to at least one monitoring system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a monitoring system 122 (e.g., thermal monitoring system) of a gas cooled nuclear reactor system 100. FIG. 22 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 22 illustrates example embodiments where the supplying operation 720 may include at least one additional operation. Additional operations may include an operation 2202, an operation 2204, an operation 2206, an operation 2208, and/or an operation 2210. The operation 2202 illustrates supplying the electrical energy to at least one coolant system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a coolant system 124 (e.g., primary coolant system) of a gas cooled nuclear reactor system 100. Further, the operation 2204 illustrates supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a coolant pump 126 of a coolant system 124 of a gas cooled nuclear reactor system 100. By way of further example, the coolant pump 126 may comprise, but is not limited to, a mechanical pump. Further, the operation 2206 illustrates supplying the electrical energy to at least one coolant pump coupled to a primary coolant loop of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a primary coolant loop 128 of a coolant system 124 of a gas cooled nuclear reactor system 100. Further, the operation 2208 illustrates supplying the electrical energy to at least one coolant pump coupled to a secondary coolant loop of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a secondary coolant loop 130 of a coolant system 124 of a gas cooled nuclear reactor system 100. Further, the operation 2210 illustrates supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system, the at least one coolant pump circulating at least one pressurized gas coolant. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a coolant pump circulating a pressurized gas coolant 132 (e.g. helium or carbon dioxide) of a coolant system 124 of a gas cooled nuclear reactor system 100. FIG. 23 illustrates alternative embodiments of the example operational flow 700 of FIG. 7. FIG. 23 illustrates example embodiments where the supplying operation 720 may include at least one additional operation. Additional operations may include an operation 2302, and/or an operation 2304. The operation 2302 illustrates supplying the electrical energy to at least one shutdown system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a shutdown system 134 (e.g., emergency shutdown system or scheduled shutdown system) of a gas cooled nuclear reactor system 100. The operation 2304 illustrates supplying the electrical energy to at least one warning system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of a thermoelectric device 104 may be used to supply electrical energy to a warning system 136 (e.g., visual warning system or audio warning system) of a gas cooled nuclear reactor system 100. FIG. 24 illustrates an operational flow 2400 representing example operations related to the thermoelectric conversion of gas cooled nuclear reactor generated heat to electrical energy. FIG. 24 illustrates an example embodiment where the example operational flow 700 of FIG. 7 may include at least one additional operation. Additional operations may include an operation 2410. After a start operation, a converting operation 710, and a supplying operation 720, the operational flow 2400 moves to a driving operation 2410. Operation 2410 illustrates at least partially driving at least one operation system of the gas cooled nuclear reactor system. For example, as shown in FIG. 1, the electrical output 108 of the thermoelectric device 104 may be used to partially drive an operation system 106 (e.g. control system 116, monitoring system 122, coolant system 124, shutdown system 134, or warning system 136) of the gas cooled nuclear reactor system 100. For instance, the electrical energy supplied to a rod control system 118 of a gas cooled nuclear reactor system 100 may be used to drive the rod control system 118 of the gas cooled nuclear reactor system 100. By way of further example, the electrical energy supplied to a coolant pump 126 of a coolant system 124 of a gas cooled nuclear reactor system 100 may be used to drive the coolant pump 126 of a coolant system 124 of the gas cooled nuclear reactor system 100. FIG. 25 illustrates an operational flow 2500 representing example operations related to the thermoelectric conversion of gas cooled nuclear reactor generated heat to electrical energy. FIG. 25 illustrates an example embodiment where the example operational flow 700 of FIG. 7 may include at least one additional operation. Additional operations may include an operation 2510, an operation 2512, an operation 2514, and/or an operation 2516. After a start operation, a converting operation 710, and a supplying operation 720, the operational flow 2500 moves to a protecting operation 2510. Operation 2510 illustrates protecting at least one thermoelectric device with regulation circuitry. For example, as shown in FIG. 6, one or more than one thermoelectric device 104 may be protected using regulation circuitry 602, such as voltage regulation circuitry (e.g., voltage regulator) or current limiting circuitry (e.g., blocking diode or fuse). The operation 2512 illustrates protecting at least one thermoelectric device with bypass circuitry. For example, as shown in FIG. 6, one or more than one thermoelectric device 104 may be protected using bypass circuitry 604, such as a bypass diode. Further, the operation 2514 illustrates protecting at least one thermoelectric device with bypass circuitry configured to electrically bypass the at least one thermoelectric device. For example, as shown in FIG. 6, one or more than one thermoelectric device 104 may be protected using bypass circuitry configured to electrically bypass 606 one or more than one thermoelectric device 104. Further, the operation 2516 illustrates electrically bypassing the at least one thermoelectric device using at least one electromagnetic relay system, at least one solid state relay system, at least one transistor, at least one microprocessor controlled relay system, at least one microprocessor controlled relay system programmed to respond to at least one external parameter, or at least one microprocessor controlled relay system programmed to respond to at least one internal parameter. For example, as shown in FIG. 6, one or more than one thermoelectric device 104 may be electrically bypassed using an electromagnetic relay system 608, a solid state relay system 610, a transistor 612, a microprocessor controlled relay system 614, a microprocessor controlled relay system programmed to respond to one or more than one external parameters 616, or a microprocessor controlled relay system programmed to respond to one or more than one internal parameters 618. FIG. 26 illustrates an operational flow 2600 representing example operations related to the thermoelectric conversion of gas cooled nuclear reactor generated heat to electrical energy. FIG. 26 illustrates an example embodiment where the example operational flow 700 of FIG. 7 may include at least one additional operation. Additional operations may include an operation 2610, and/or an operation 2612. After a start operation, a converting operation 710, and a supplying operation 720, the operational flow 2600 moves to an augmenting operation 2610. Operation 2610 illustrates selectively augmenting at least one thermoelectric device using at least one reserve thermoelectric device and reserve actuation circuitry configured to selectively couple the at least one reserve thermoelectric device to the at least one thermoelectric device. For example, as shown in FIG. 6, the electrical output 108 from one or more than one thermoelectric device 104 may be augmented using one or more than one reserve thermoelectric device 620, wherein the one or more than one reserve thermoelectric device 620 may be selectively coupled to the thermoelectric device 104 using reserve actuation circuitry 622. The augmenting operation 2612 illustrates selectively coupling at least one reserve thermoelectric device to at least one thermoelectric device using at least one relay electromagnetic system, at least one electromagnetic relay system, at least one solid state relay system, at least one transistor, at least one microprocessor controlled relay system, at least one microprocessor controlled relay system programmed to respond to at least one external parameter, or at least one microprocessor controlled relay system to respond to at least one internal parameter to the at least one thermoelectric device. For example, as shown in FIG. 6, the electrical output 108 from one or more than one thermoelectric device 104 may be augmented using one or more than one reserve thermoelectric device 620, where the one or more than one reserve thermoelectric device 620 may be selectively coupled to the thermoelectric device 104 using a relay system 624. For instance, the relay system may comprise, but is not limited to, an electromagnetic relay system 626, a solid state relay system 628, a transistor 630, a microprocessor controlled relay system 632, a microprocessor controlled relay system programmed to respond to at least one external parameter 634, or a microprocessor controlled relay system programmed to respond to at least one internal parameter 636. FIG. 27 illustrates an operational flow 2700 representing example operations related to the thermoelectric conversion of nuclear reactor generated heat to electrical energy. FIG. 27 illustrates an example embodiment where the example operational flow 700 of FIG. 7 may include at least one additional operation. Additional operations may include an operation 2710, and/or an operation 2712. After a start operation, a converting operation 710, and a supplying operation 720, the operational flow 2700 moves to a modifying operation 2710. Operation 2710 illustrates modifying at least one thermoelectric device output using power management circuitry. For example, as shown in FIG. 6, the electrical output 108 of a thermoelectric device 104 may be modified using power management circuitry 638. For instance, the power management circuitry may comprise, but is not limited to, a voltage converter (e.g., DC-DC converter or DC-AC inverter). The operation 2712 illustrates modifying at least one thermoelectric device output using voltage regulation circuitry. For example, as shown in FIG. 6, the electrical output 108 of a thermoelectric device 104 may be modified using voltage regulation circuitry 640. For instance, the voltage regulation circuitry may comprise, but is not limited to, a voltage regulator (e.g., Zener diode, an adjustable voltage regulator or a fixed voltage regulator). Those having skill in the art will recognize that the state of the art has progressed to the point where there is little distinction left between hardware, software, and/or firmware implementations of aspects of systems; the use of hardware, software, and/or firmware is generally (but not always, in that in certain contexts the choice between hardware and software can become significant) a design choice representing cost vs. efficiency tradeoffs. Those having skill in the art will appreciate that there are various vehicles by which processes and/or systems and/or other technologies described herein can be effected (e.g., hardware, software, and/or firmware), and that the preferred vehicle will vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and/or firmware vehicle; alternatively, if flexibility is paramount, the implementer may opt for a mainly software implementation; or, yet again alternatively, the implementer may opt for some combination of hardware, software, and/or firmware. Hence, there are several possible vehicles by which the processes and/or devices and/or other technologies described herein may be effected, none of which is inherently superior to the other in that any vehicle to be utilized is a choice dependent upon the context in which the vehicle will be deployed and the specific concerns (e.g., speed, flexibility, or predictability) of the implementer, any of which may vary. Those skilled in the art will recognize that optical aspects of implementations will typically employ optically-oriented hardware, software, and or firmware. In some implementations described herein, logic and similar implementations may include software or other control structures. Electronic circuitry, for example, may have one or more paths of electrical current constructed and arranged to implement various functions as described herein. In some implementations, one or more media may be configured to bear a device-detectable implementation when such media hold or transmit device-detectable instructions operable to perform as described herein. In some variants, for example, implementations may include an update or modification of existing software or firmware, or of gate arrays or programmable hardware, such as by performing a reception of or a transmission of one or more instructions in relation to one or more operations described herein. Alternatively or additionally, in some variants, an implementation may include special-purpose hardware, software, firmware components, and/or general-purpose components executing or otherwise invoking special-purpose components. Specifications or other implementations may be transmitted by one or more instances of tangible transmission media as described herein, optionally by packet transmission or otherwise by passing through distributed media at various times. Alternatively or additionally, implementations may include executing a special-purpose instruction sequence or invoking circuitry for enabling, triggering, coordinating, requesting, or otherwise causing one or more occurrences of virtually any functional operations described herein. In some variants, operational or other logical descriptions herein may be expressed as source code and compiled or otherwise invoked as an executable instruction sequence. In some contexts, for example, implementations may be provided, in whole or in part, by source code, such as C++, or other code sequences. In other implementations, source or other code implementation, using commercially available and/or techniques in the art, may be compiled/implemented/translated/converted into a high-level descriptor language (e.g., initially implementing described technologies in C or C++ programming language and thereafter converting the programming language implementation into a logic-synthesizable language implementation, a hardware description language implementation, a hardware design simulation implementation, and/or other such similar mode(s) of expression). For example, some or all of a logical expression (e.g., computer programming language implementation) may be manifested as a Verilog-type hardware description (e.g., via Hardware Description Language (HDL) and/or Very High Speed Integrated Circuit Hardware Descriptor Language (VHDL)) or other circuitry model which may then be used to create a physical implementation having hardware (e.g., an Application Specific Integrated Circuit). Those skilled in the art will recognize how to obtain, configure, and optimize suitable transmission or computational elements, material supplies, actuators, or other structures in light of these teachings. The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape, a computer memory, etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link (e.g., transmitter, receiver, transmission logic, reception logic, etc.), etc.). In a general sense, those skilled in the art will recognize that the various embodiments described herein can be implemented, individually and/or collectively, by various types of electro-mechanical systems having a wide range of electrical components such as hardware, software, firmware, and/or virtually any combination thereof; and a wide range of components that may impart mechanical force or motion such as rigid bodies, spring or torsional bodies, hydraulics, electro-magnetically actuated devices, and/or virtually any combination thereof. Consequently, as used herein “electro-mechanical system” includes, but is not limited to, electrical circuitry operably coupled with a transducer (e.g., an actuator, a motor, a piezoelectric crystal, a Micro Electro Mechanical System (MEMS), etc.), electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of memory (e.g., random access, flash, read only, etc.)), electrical circuitry forming a communications device (e.g., a modem, communications switch, optical-electrical equipment, etc.), and/or any non-electrical analog thereto, such as optical or other analogs. Those skilled in the art will also appreciate that examples of electro-mechanical systems include but are not limited to a variety of consumer electronics systems, medical devices, as well as other systems such as motorized transport systems, factory automation systems, security systems, and/or communication/computing systems. Those skilled in the art will recognize that electro-mechanical as used herein is not necessarily limited to a system that has both electrical and mechanical actuation except as context may dictate otherwise. In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, and/or any combination thereof can be viewed as being composed of various types of “electrical circuitry.” Consequently, as used herein “electrical circuitry” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of memory (e.g., random access, flash, read only, etc.)), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, optical-electrical equipment, etc.). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof. Those skilled in the art will recognize that at least a portion of the devices and/or processes described herein can be integrated into a data processing system. Those having skill in the art will recognize that a data processing system generally includes one or more of a system unit housing, a video display device, memory such as volatile or non-volatile memory, processors such as microprocessors or digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices (e.g., a touch pad, a touch screen, an antenna, etc.), and/or control systems including feedback loops and control motors (e.g., feedback for sensing position and/or velocity; control motors for moving and/or adjusting components and/or quantities). A data processing system may be implemented utilizing suitable commercially available components, such as those typically found in data computing/communication and/or network computing/communication systems. One skilled in the art will recognize that the herein described components (e.g., operations), devices, objects, and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration modifications are contemplated. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be taken limiting. Although a user is shown/described herein as a single illustrated figure, those skilled in the art will appreciate that the user may be representative of a human user, a robotic user (e.g., computational entity), and/or substantially any combination thereof (e.g., a user may be assisted by one or more robotic agents) unless context dictates otherwise. Those skilled in the art will appreciate that, in general, the same may be said of “sender” and/or other entity-oriented terms as such terms are used herein unless context dictates otherwise. With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations are not expressly set forth herein for sake of clarity. The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected”, or “operably coupled,” to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being “operably couplable,” to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable, and/or wirelessly interacting components, and/or logically interacting, and/or logically interactable components. In some instances, one or more components may be referred to herein as “configured to,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that such terms (e.g., “configured to”) can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise. While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B. With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise.
054250714	summary	This invention relates to loading nuclear fuel pellets into a cladding tube to form a nuclear fuel pin for use in a nuclear reactor. In particular, the invention is concerned with inserting an end plug into the cladding tube after loading a stack of fuel pellets into the cladding tube where the pellets are made of a mixed oxide fuel comprising a mixture of uranium dioxide and plutonium dioxide. Because of the radiological hazards involved in handling fuel pellets containing plutonium they are manufactured in a containment area enclosed by alpha radiation shielding. When loading the pellets from the containment area into a cladding tube located outside the containment area, the end of the tube through which the pellets are inserted protrudes into the containment area. As a result, the end portion of the tube becomes radioactively contaminated. This necesitates subjecting the pin to a decontamination process, which is undesirable since it increases manuacturing costs. It is an object of this invention to obviate the need for decontamination of the pin following the fuel pellet loading operation. According to one aspect of the invention there is provided apparatus for inserting an end plug into a fuel pin cladding tube after loading nuclear fuel pellets into said cladding tube, said apparatus comprising a sleeve removably mounted on one end of the cladding tube, said sleeve being slidably locatable in a resilient seal, a carrier having a closed recess for locating therein an end plug for closing said one end of the cladding tube, the carrier being slidable in the sleeve so that on moving the carrier through the sleeve the end plug is inserted into said one end of the cladding tube, the arrangement being such that on withdrawal of the cladding tube with the end plug therein leaves the sleeve and carrier trapped in the seal. Preferably, the sleeve has an internal seating surface comprising a reduced diameter portion extending from one end of the sleeve, the seating surface being adapted to fit on the end of the cladding tube. The seating surface preferably extends from the said one end of the sleeve to an internal end surface which is coincident with an end surface of the cladding tube. The seating surface may be a press fit on the cladding tube. In a preferred embodiment the end plug has a head portion having an end surface and a peripheral surface, the depth of the recess in the carrier being sufficient to surround the end surface and the peripheral surface. Preferably, stop means are provided to retain the sleeve and carrier in the resilient seal upon withdrawal of the cladding tube. The resilient seal may be of the sphincter seal type having a plurality of resilient rings adapted so as to press against the sleeve. According to a further aspect of the invention there is provided a method of inserting an end plug into a fuel pin cladding tube after loading nuclear fuel pellets into said cladding tube, said method comprising the steps of mounting a sleeve on one end of the cladding tube, inserting the sleeve in a resilient seal, introducing a carrier into said sleeve, said carrier having a closed recess containing therein an end plug which is inserted into said one end of the cladding tube upon introduction of the carrier into the sleeve, and withdrawing said cladding tube with the end plug inserted therein while leaving the sleeve and carrier located in the seal. Preferably, the method includes the further step of displacing the sleeve and carrier from the seal by a sleeve mounted on a fresh fue pin cladding tube during a subsequent pellet loading sequence.
055324959	claims	1. A process for uniformly altering a characteristic of a surface of a material to a depth of<several hundred microns comprising the step of irradiating a surface of the material with a repetitively pulsed ion beam from an ion beam source, wherein each pulse of the pulsed ion beam has a duration of .ltoreq.1000 ns at (an accelerating gap) between an anode electrode means and a cathode electrode means in the ion beam source, a total beam energy delivered to the material of >1 Joule/pulse, an impedance of <100.OMEGA., a repetition rate of >1 Hz, an ion kinetic energy of >50 keV, and an ion penetration depth of <50 microns. 2. The process of claim 1 wherein the depth of ion penetration is controlled by controlling the kinetic energy of the ion beam. 3. The process of claim 1 wherein the depth of ion penetration is controlled by controlling the atomic mass of the ions in the ion beam. 4. The process of claim 1 wherein the depth of ion penetration is controlled by controlling the atomic number of the ions in the ion beam. 5. The process of claim 1 wherein the characteristic is surface smoothness which is modified to a surface roughness of <0.5 microns. 6. The process of claim 5 wherein the material is a fine grain, sintered material. 7. The process of claim 5 wherein the surface is a food preparation surface. 8. The process of claim 7 wherein the food preparation surface is a food cooking surface. 9. The process of claim 5 wherein the material is an amorphous magnetic alloy. 10. The process of claim 9 wherein the alloy has the approximate composition of Fe.sub.66 Co.sub.18 B.sub.15 Si.sub.1. 11. The process of claim 1 wherein the surface characteristic is the presence of an unwanted contaminant. 12. The process of claim 11 wherein the unwanted contaminant is a machining lubricant. 13. The process of claim 11 wherein the unwanted contaminant is solder flux. 14. The process of claim 11 wherein the unwanted contaminant is biological contamination. 15. The process of claim 11 wherein the unwanted contaminant is a surface coating. 16. The process of claim 1 wherein the total beam energy delivered to the material per pulse is >10 Joules/pulse and the surface characteristic to be altered is the presence of the top 1-2 microns of the material which is removed by ablation. 17. The process of claim 1 wherein the total beam energy delivered to the material per pulse is >20 Joules/pulse and the surface characteristic is shock hardening. 18. The process of claim 16 wherein the ablation produces vaporization of the surface of the material which redeposits upon the surface of the material. 19. The process of claim 16 wherein the ablation produces vaporization of the surface of the material which redeposits upon a surface of a second material. 20. The process of claim 16 further including protection of certain areas of the surface of the material by mask means which protect the surface from the ablation. 21. The process of claim 1 wherein the surface characteristic to be altered is hardness. 22. The process of claim 1 wherein the surface characteristic to be altered is corrosion resistance. 23. The process of claim 22 wherein the material is steel. 24. The process of claim 22 wherein the material comprises aluminum. 25. The process of claim 23 wherein the material is stainless steel that has been heat treated to above 600.degree. C. 26. The process of claim 1 wherein the surface characteristic to be altered is resistance of welds to stress cracking. 27. The process of claim 1 wherein the surface characteristic to be altered is resistance of welds to corrosion. 28. The process of claim 1 wherein the surface characteristic to be altered is the formation of non-equilibrium structures within the surface. 29. The process of claim 28 wherein the non-equilibrium structures are selected from the group consisting of amorphous structures, disordered crystalline structures, and nanocrystalline structures not present in the original material. 30. The process of claim 1 wherein the area of continuous and uniform alteration of the characteristic is >5 cm.sup.2. 31. The process of claim 1 wherein the ion species are selected from the group consisting of hydrogen, helium, oxygen, nitrogen fluorine, neon, chlorine, argon, lithium, beryllium, boron, carbon, sodium, magnesium, aluminum, silicon, phosphorous, sulfur, potassium and the isotopes thereof. 32. The process of claim 1 wherein the material is selected from the group consisting of intermetallic materials, amorphous materials, crystalline materials, nano-crystalline materials, dielectrics, polymers, semiconductors, ceramics and glasses.
052727335	summary	BACKGROUND OF THE INVENTION The present invention relates to a control rod driving system and more particularly to a control rod driving hydraulic system of the control rod driving system for supplying a driving water to a control rod driving mechanism. A prior art control rod driving system of a general boiling water reactor plant will be described with reference to FIGS. 7 and 8. FIG. 7 represents the construction of a control rod driving mechanism 1 and a water pressure, i.e. hydraulic, control unit 2, and FIG. 8 represents an outline of a control rod driving hydraulic system. The control rod driving mechanism 1 employs a hydraulic piston driving system and principally comprises a driving piston 1a, an index tube 1b and a locking mechanism 1c. The driving piston 1a is mounted on a lower portion of the index tube 1b, provided with vertical pressure receiving faces and operates to insert and extract a control rod in accordance with a difference in pressure between the upper and lower surface portions. Further, the index tube 1b is provided with a locking groove on its outer peripheral surface, locked after it's moved by a constant stroke by the locking mechanism 1c such as a ratchet type collet finger or the like, thus holding the control rod fixedly at a predetermined position. The control rod driving hydraulic system supplies hydraulic pressure and flow necessary for operation of the control rod to adjustment. The system comprises the water pressure control unit 2 attached to each control rod 1 and a control rod driving water pressure supply system common to all control rods. The control rod driving hydraulic system is that for supplying a demineralized condensate to the control rod driving mechanism 1 from a condensate demineralizer 3 during operation of the plant, and as shown in FIG. 8, the system comprises principally a driving water pump 4, a suction filter 5, a driving water filter 6, a flow nozzle 7 working as a flowmeter, flow control valves 8 and 9, pressure control valves 10 and 11, stabilizing valves 12 and others. The driving water fed into the driving water pump 4 from the condensate demineralizer 3 flows partly into a charing water header 13 as a scrum water pressure unit by way of two kinds of filters, namely the suction filter 5 and the driving water filter 6, for removing foreign materials which are capable of causing an extra ordinary operation of the control rod driving mechanism 1 and others. Further, it flows partly into a driving water header 14 or a driving hydraulic system for actuating the control rod driving mechanism 1 and partly into a cooling water header 15 of a cooling water pressure system of a control rod driving mechanism piston seal by way of the flow control valves 8 and 9 for retaining a charging water pressure. The stabilizing valves 12 are constructed of two electromagnetic, i.e. solenoid, valves provided in parallel. A quantity of flow passing one stabilizing valve 12 is normally equal to the quantity of flow necessary for the control rod driving mechanism 1 to insert the control rod, and a quantity of flow passing the other stabilizing valve 12 is adjusted to be equal to the quantity of flow necessary for withdrawal. Water coming out of the stabilizing valves 12 is circulated to the cooling water piping. That is, when the one stabilizing valve 12 is closed at the time of driving operation, a predetermined quantity of flow runs toward the control rod driving mechanism 1, thus operating to keep a hydraulic pressure control valve 10 constant. Further, a piping from a drain header 16 is connected to the stabilizing valve 12 on the downstream side, water flowing from the driving water header 14 to the drain header 16 by way of the control rod driving mechanism 1 at the time of driving is fed to the cooling water header 15, and then released into a reactor pressure vessel through the other water pressure control unit 2. At the time of normal operation, only a cooling water flows, a steady flow sufficient enough to cover cooling of all the control rod driving mechanisms 1 runs, and the pipings same in the number of control rods communicate further with each water pressure control unit 2 from each of the headers 13 to 16. The control rod driving hydraulic system is equipped with a condensate storage tank 18, thus a source of the driving water can be transferred to the condensate storage tank 18 from the condensate demineralizer 3. The water pressure control unit 2 supplies charging water, cooling water and driving water from the control rod driving hydraulic supply system to the control rod driving system, and is provided in one unit per one control rod. The water pressure control unit 2 is that of having unitized, as shown in FIG. 7, four directional control valves 21, 22, 23 and 24 and two scrum valves 25 and 26 en bloc. The water pressure control unit 2 operates as follows. When inserting the control rod, the insert directional valves 21 and 22 are opened, a hydraulic pressure exerted on the driving water header 14 is provided to a lower surface of the driving piston 1a, and thus water on the upper surface is released to the drain header 16. When extracting, on the contrary, the insert directional control valves 21 and 22 are opened in a short time, the index tube 1b is lifted slighly to an easy unlocking of the collet finger, then the withdraw directional control valves 23 and 24 for withdrawal are opened to apply a driving water pressure to an upper surface of the driving piston 1a, and water on the lower surface is released to the drain header 16. The collet finger is spread out along a guide to separate from the index tube 1b, and is thus ready for extraction of the control rod. Then, by opening the scrum valves 25 and 26 at the time of scrum operation, a high pressure water is poured into the lower surface of the driving piston 1a from the charging water heater 13, water on the upper surface of the driving piston 1a is released to a scrum discharging header 27 of atmospheric pressure, thereby realizing a quick scrum operation. In the construction described above, by changing a position of the control rod in a reactor core according to a manual control signal, the control rod driving system operates for adjustment of outputs at the time of low output, adjustment of a long term reactivity and control of a core output distribution. The condensate purified by the filters of the control rod driving water is utilized as purge water for a mechanical seal of a reactor coolant recirculation pump. The mechanical seal is exchanged with another one as an expendable item at every periodical inspection time, but the mechanical seal in use contacts operation water in the reactor, so that the mechanical seal may be radioactive. For this reason, the condensate of a pressure higher than the reactor pressure is used as the purge water to prevent exposure to workers. In a prior art control rod driving system, two kinds of filters are intended for purifying a driving water of the control rod driving mechanism 1 for driving a control rod and removing foreign materials such as cladding and the like. Namely the suction filter 5 of about 25 .mu.m or so in absolute performance of filtration and the driving water filter 6 of about 50 to 70 .mu.m or so in absolute performance of filtration are provided on an inlet side of the driving water pump 4 for pressurizing the driving water and on an outlet side thereof respectively, thereby filtering the driving water of the control rod driving mechanism 1. The purified condensate is fed as the purge water for the mechanical seal of the reactor coolant. However, such performances of filtration are still not satisfactory in removing foreign materials such as cladding and the like thoroughly, and thus are capable of causing the foreign materials to come into the control rod driving mechanism 1 and the water pressure control unit 2. There may cause a case where the biting of the foreign materials to the mechanical seal of the reactor coolant recirculation pump may cause the leakage of the reactor water. Further, there may cause a case where the air comes into the control rod driving hydraulic system at the time of operation for disassembly and check of each equipment and change of a water source, and since the air having come thereinto exerts an influence on a driving performance of the control rod driving mechanism 1, a work for withdrawing the air must be done carefully on each occasion. SUMMARY OF THE INVENTION An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art described hereinbefore and to provide a control rod driving system capable of enhancing a performance of filtration as high as removing foreign materials which come into a control rod driving hydraulic almost perfectly and air can also be collected, thereby supplying the driving water free from the foreign materials and air to the control rod driving mechanism. Another object of the present invention is to provide a control rod driving system capable of utilizing regeneratively the filter, reducing frequencies of filter exchanging and reducing secondary waste. These and other objects can be achieved according to the present invention by providing a control rod driving hydraulic system of a control rod driving system of a nuclear power plant, in utilization of condensate fed from a condensate supply source of the nuclear power plant as a control rod driving water, comprising a water pressure control unit arranged for each control rod and a water pressure supply unit for commonly supplying water pressure to all control rods, the water pressure supply unit comprising a pump means operatively connected to the condensate supply source for driving the control rod driving water, a filter mechanism operatively connected to the condensate supply source and the pump mechanism for filtering the condensate as the control rod driving water, a valve mechanism for regulating quantity of flow of the control rod driving water, and a valve means for regulating pressure of the control rod driving water, the filter means including at least one hollow fiber filter unit for purifying the control rod driving water. In preferred embodiments, the hollow fiber filter unit includes a backwash regeneration equipment. In detail, the hollow fiber filter unit includes a sealing casing having an interior divided into two sections by a partition plate provided with a plurality of perforations, a bundle of fiber elements passing through the perforations of the partition plate, a drain means connected to the sealing casing and a backwash regeneration equipment connected to the sealing casing. The backwash regeneration equipment includes an air supply unit for supplying air into the sealing casing, a purge air supply pipe connected to the air supply unit and to one section, as a header chamber, of the sealing casing and a bubble air supply pipe connected to the air supply unit and to another section, as a filtering chamber, of the sealing casing. The filter means includes a suction filter unit and a driving water filter unit, the suction filter unit being connected to the condensate supply unit at one end, the driving water filter unit being connected at one end to another end of the suction filter unit through the pump means and connected at another end to the flow quantity regulating means and the suction filter unit or the driving water filter unit is substituted with the hollow fiber filter unit. According to the construction of the control rod driving hydraulic system described above, the hollow fiber filter unit is capable of removing an insoluble solid material in the water almost perfectly through the filtration perforations of the hollow fiber filter unit and is not to allow the air to pass therethrough, thus the driving water for the control rod driving mechanism being passed through the hollow fiber filter unit to filtration within the control rod driving hydraulic system, thereby preventing the driving water into which foreign materials such as cladding and others and air are mixed by flowing into the control rod driving mechanism and others. In addition, the mechanical purge water for the reactor coolant recirculation pump can be purified, thus preventing the foreign materials from flowing into the mechanical seal. Furthermore, the hollow fiber filter unit is equipped with the backwash regeneration equipment, so that the filter unit is regeneratively utilized, thus reducing the frequency of exchanging of the filter units and reducing the generation of the secondary waste.
	claims	1. Radiotherapy apparatus comprising a first collimator and a second collimator, the first collimator comprising a plurality of elongate leaves lying alongside each other, each being moveable longitudinally, the second collimator comprising a plurality of slits, the first and second collimators being aligned such that each leaf of the first collimator at least partially covers a slit of the second collimator, the slits having a width which corresponds to a fraction of the width of the leaves. 2. Radiotherapy apparatus according to claim 1 wherein the first collimator is above the second. claim 1 3. Radiotherapy apparatus according to claim 1 , wherein the slits are focused on the source of radiation within the apparatus. claim 1 4. Radiotherapy apparatus according to claim 1 , in which the second collimator is movable relative to the first. claim 1 5. Radiotherapy apparatus according to claim 1 , in which the first and second collimators are movable together relative to the patient. claim 1 6. Radiotherapy apparatus according to claim 1 , adapted to allow a patient to be moved continuously relative to the source, the first collimator leaves being adjustable as the treatment progresses. claim 1 7. Radiotherapy apparatus according to claim 1 , in which the fraction is one of {fraction (1/2, 1/3, 1/4)} or ⅕. claim 1 8. Radiotherapy apparatus according to claim 1 , in which the second collimator is removable from the apparatus, thereby the enable exchange with an alternative second collimator. claim 1 9. Radiotherapy apparatus according to claim 8 in which the alternative second collimator has a different fractional width. claim 8 10. Radiotherapy apparatus according to claim 8 , in which the alternative second collimator has a different irradiatable area. claim 8 11. Radiotherapy apparatus according to claim 1 , in which the second collimator is above the first. claim 1 12. Radiotherapy apparatus according to claim 1 , in which the second collimator is above a light reflecting mirror. claim 1 13. Radiotherapy apparatus according to claim 1 , in which the first collimator is below a light reflecting mirror. claim 1 14. Radiotherapy apparatus according to claim 1 , in which the second collimator is positionable such that during an irradiation at least one slit is aligned with a pair of leaves in the first collimator. claim 1 15. Radiotherapy apparatus according to claim 14 in which the centreline of the slit is aligned with the adjacent edges of the pair of leaves. claim 14 16. Radiotherapy apparatus according to claim 1 , in which the pitch of the slits in the second collimator is approximately an integer multiple of the width of the leaves in the first collimator. claim 1 17. Radiotherapy apparatus according to claim 1 , in which the pitch of the slits in the second collimator is approximately an integer multiple of the width of the leaves in the first collimator plus one half that width. claim 1 18. A kit of parts comprising the apparatus as defined above in claim 1 , in combination with alternative second collimators exhibiting different fractional widths. claim 1 19. A method for performing radiotherapy comprising: aligning leaves of a first collimator with slits of a second collimator to produce at least one substantially planar beam of radiation; sweeping the at least one substantially planar beam of radiation through the first and the second collimators and across a selected area of a patient lying in a plane transverse to that of the beam; and modulating a width of the at least one substantially planar beam to map out an irradiated area on the patient. 20. The method of claim 19 wherein the slits of the second collimator either allow completely or block entirely a portion of the at least one substantially planar beam. claim 19
051125668	abstract	Disclosed is a device for measuring dimensional characteristics of an elongate component which comprises:. (a) an elongate rigid support that bears (i) an upper platform upon which is mounted a drive; (ii) a clamp mechanism for securing said component about its proximal end in a reference position; (iii) a lower platform which supports a pedestal for securing said component about its distal end in a reference position; and PA1 (b) a sensor carriage movably mounted to said rigid support and operatively connected to said drive for movement along the elongate extent of said support and having an opening penetrating therethrough for receiving said elongate component when it is secured by and substantially parallel to said rigid support, said carrier bearing a plurality of pivotally-mounted bell cranks spaced about said opening, each bell crank having a wheel for riding on said component during movement of the carrier and being in contact with a sensor capable of providing a signal correlative to displacement of the bell crank during movement of the carrier along the elongate component.
	description	The present invention relates to a safety valve drive system of a nuclear power plant, and particularly, to a drive system for an safety relief valve provided in a main steam system of a nuclear power plant to protect a reactor from applying pressure by opening the safety relief valve through the supply of a driving gas using a pilot valve if an accident or a transient state occurs. Safety relief valves provided for boiling-water reactor power plants and other types of nuclear power plants are equipments having steam relieving functions and safety functions and constituting a main steam system. The main steam system is comprised of a main steam pipeline, a safety relief valve, a steam flow restrictor, a main steam isolation valve, a main steam pipe drain system, and a feed water system. The functions of the main steam system include a steam supply from a reactor pressure vessel to a turbine, a pressure suppression of the reactor pressure vessel within a limit value in a transient state of a reactor, and steam releasing restriction from the reactor pressure vessel and a reactor containment vessel. The main steam system generally includes four main steam pipes for introducing steam generated within the reactor pressure vessel to the turbine. A plurality of safety valves is provided for each main steam pipe. Safety valves are provided for a main steam pipe in order to suppress reactor pressure to a value less than a specified value if, for some reason, an accident or the like occurs in the reactor or in the vicinity thereof. A safety valve has spring-operated safety functions and relief valve functions for forcibly opening the safety valve by an auxiliary actuator at a set pressure less than a blowout pressure. As the relief valve functions, the safety valve releases steam in the reactor pressure vessel to a pressure suppression pool by means of forced manual opening or automatic opening in response to a high relief valve pressure. Some safety valves are built in an auto-depressurization system to be enabled in case of a loss-of-coolant accident (LOCA). The safety valves are automatically forced to open by means of remote operation based on a high reactor containment vessel pressure signal or a low reactor water level signal, thereby depressurizing the reactor pressure vessel until cooling water injection by a low-pressure emergency core cooling system becomes possible. Conventional technology will be described hereunder with reference to FIGS. 4 to 7. FIG. 4 illustrates a reactor containment vessel of a boiling-water nuclear power plant, and FIG. 5 is an enlarged view of a pressure suppression pool illustrated in FIG. 4. As illustrated in FIGS. 4 and 5, a reactor pressure vessel 21 is installed within a reactor containment vessel 14, and a safety valve 5 is provided in a pipe of a main steam system 11. In the safety valve 5, there is provided a safety valve exhaust pipe 28 for introducing steam to a pressure suppression pool 10. Vent pipes 24 are provided in a wall of the pool, and a quencher 23 for facilitating steam condensation in the pressure suppression pool 10 is connected to the lower end of the safety valve exhaust pipe 28. Note that in FIG. 4, reference numerals 22a and 22b denote main steam isolation valves. FIG. 6 illustrates the configuration of a safety valve and FIG. 7 illustrates a safety valve drive system. As illustrated in FIGS. 6 and 7, accumulators 3 and 4 are provided conventionally to supply an operating gas from a high-pressure nitrogen gas supply system 1 (1a, 1b), in order to open the safety valve 5 if an accident or a transient state occurs. The safety valve 5 is a nitrogen- and spring-operated type and is mounted on a pipe stand provided for the main steam pipe of the reactor containment vessel. An outlet side of the valve is formed as a flange connected to an exhaust pipe. The safety valve 5 is designed to automatically open (safety functions) if a valve inlet pressure exceeds a spring load. A piston 18 disposed in an air cylinder 19 mounted on the valve main unit and a valve shaft 17 are coupled with each other by means of a pull-up lever 16. Thus, the valve is configured so as to be opened (relief valve functions) by supplying nitrogen into the air cylinder 19 using an external signal. Supply of nitrogen into the air cylinder 19 is performed by operating a controlling solenoid valve. Next, an operating logic of the safety valve 5 will be explained. As illustrated in FIG. 7, the safety valve 5 operates, in response to a simultaneous signal of a reactor water level “low” and a dry well pressure “high”, as the result of an auto-depressurization system actuating signal 9 being generated with an emergency core system pump enabled. If one of two solenoid valves for auto-depressurization functions 26a and 26b is opened in response to logic circuit output signals from the output signal cables 34b and 34c of logic circuits, a nitrogen gas is supplied from a high-pressure nitrogen gas supply system 1 or an accumulator 4, thereby forcing the safety valve 5 to open. Consequently, steam flows from the main steam system 11, in a direction shown by arrows S1 and S2, into the pressure suppression pool 10, thereby depressurizing the reactor pressure vessel. On the other hand, if the pressure of a reactor rises and a high relief valve pressure signal is generated by a pressure gauge 13 for relief valve functions, a signal for relief valve functions is generated through an output signal cable 34a of a logic circuit, thereby causing the safety valve 5 to operate. If one solenoid valve 25 having relief valve functions opens in response to an output signal of a logic circuit, a nitrogen gas is supplied from the high-pressure nitrogen gas supply system 1 or an accumulator 3, thereby forcing the safety valve 5 to open. Consequently, steam flows into the pressure suppression pool 10 in the same way as described above, thereby depressurizing the reactor pressure vessel. Further, in the figure, reference numeral 14 denotes a reactor containment vessel side and reference numeral 15 denotes a reactor building side. In addition, examples of conventional proposals of such a safety valve drive system described above include one described in Patent Document 1 (Japanese Patent Laid-Open No. 9-304584). As described above, the operating logic of a safety valve works in the manner that if at least one of three three-way solenoid valves operates, the safety valve is forced to open, thereby depressurizing the reactor pressure vessel. In addition, according to the current operating logic of a driving solenoid valve, there is a possibility that if a fire occurs, a cable short-circuits to another cable and a false signal is generated, thus causing the solenoid valve to open mistakenly. Moreover, if the safety valve opens due to the malfunction of the solenoid valve, the depressurization of the reactor pressure vessel or the outflow of reactor water occurs, thus causing the water level of a reactor to drop. In addition, it is conceivable that in current systems of safety valves, online maintenance becomes difficult to perform if a power source for driving an auto-depressurization system is lost. The present invention has been accomplished in view of such problems as described above, and an object thereof is to provide a system or facility capable of improving the operating logic of a safety valve, enhancing the reliability thereof, and making compatible with online maintenance in order to eliminate the possibility of occurrence of a loss-of-coolant accident caused by the malfunction of a solenoid valve resulting from cable short-circuiting due to a fire or the like. In order to achieve the above-mentioned object, the present invention provides a safety valve drive system in which a safety valve provided in a main steam system of a nuclear power plant is opened by supplying a driving gas by using a pilot valve at an occurrence of an accident or a transient state occurs, thereby protecting a reactor against pressure application, the safety valve drive system comprising: a safety valve drive unit, as safety valve actuating means, actuating in such a manner that the safety valve is opened in response to respective auto-depressurization system actuating signals for two or more segments among respective auto-depressurization system actuating signals for four segments, and is closed if an auto-depressurization system actuating signal for one or less segment among the auto-depressurization system actuating signals for the four segments is received; and cables connected to the safety valve drive unit and used to transfer the auto-depressurization system actuating signals for the four segments. In addition, there is also provided a safety valve drive system which comprises: a safety valve drive unit, as safety valve actuating means, actuating in such a manner that the safety valve is opened in response to respective relief valve actuating signals for two or more segments among respective relief valve actuating signals for three segments, and is closed if an auto-depressurization system actuating signal for one or less segment among the auto-depressurization system actuating signals for three segments is received; and cables connected to the safety valve drive unit and used to transfer the auto-depressurization system actuating signals for the three segments. Further, in the above-described safety valve drive system, the phrase “relief valve actuating signal” may alternatively be read as “auto-depressurization system actuating signal,” depending on a reactor type different in the configuration of a safety system. According to a safety valve drive system of the present invention of the characters mentioned above, it is possible to eliminate the possibility of occurrence of a loss-of-coolant accident caused by the malfunction of a solenoid valve resulting from cable short-circuiting due to a fire or the like, thereby improving the safety valve in the operating logic thereof, enhancing the reliability thereof, and making compatible with online maintenance. Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. It is further to be noted that although, in described embodiments, an explanation will be made of a case in which the present invention is applied to a boiling-water reactor, the present invention is also applicable to nuclear power plants other than a boiling-water reactor. FIG. 3 is a configuration diagram illustrating a safety valve drive system in accordance with a third embodiment of the present invention, in which like reference numerals are added to elements or members corresponding to those of the first embodiment mentioned above with reference to FIG. 1, and duplicated explanations thereof are omitted hereunder. As illustrated in FIG. 3, in the present embodiment, an explanation will be made to the operating logic of the relief valve functions of a safety valve, the arrangement of an opening line, the change of the driving source of the safety valve, and a method of storing the driving source is also explained. A drive circuit 12 for relief valve functions of a safety valve 5 includes actuating signals 13 for relief valve functions composed of three segments and the circuits thereof, in which the respective segments have structures physically and electrically independent of one another. Consequently, the drive circuit has multiplicity and electrical and physical independency, so that the functions of the drive circuit are not hampered by a single failure of equipment. Further, this configuration may be also effective for the operating logic of an auto-depressurization system in a plant having a safety system divided into three segments.
047073268	description	DETAILED DESCRIPTION OF THE INVENTION In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms. IN GENERAL Referring now to the drawings, and particularly to FIG. 1, there is shown an elevational view of a reconstitutable nuclear reactor fuel assembly, represented in vertically foreshortened form and being generally designated by the numeral 10. Basically, the fuel assembly 10 includes a lower end structure or bottom nozzle 12 for supporting the assembly on the lower core plate (not shown) in the core region of a reactor (not shown), and a number of longitudinally extending guide tubes or thimbles 14 which project upwardly from the bottom nozzle 12. The 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 10 has an instrumentation tube 20 located in the center thereof and an upper end structure or top nozzle 22 attached to the upper end portions 24 of the guide thimbles 14 which together incorporate certain features in accordance with the present invention which will be fully described below. With such 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 array thereof in the assembly 10 are held in spaced relationship with one another by the grids 16 spaced along the fuel assembly length. Each fuel rod 18 includes nuclear fuel pellets (not shown) and is closed at its opposite ends by upper and lower end plugs 26,28. The fuel pellets composed of fissile material are responsible for creating the reactive power of the reactor. 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. Since the control rods are inserted into the guide thimbles 14 from the top of the fuel assembly 10, the placement of the components forming the top nozzle 22 and their attachment to the upper end portions 24 of the guide thimbles 14, along with the features of the present invention, must accommodate the movement of the control rods into the guide thimbles 14 from above the top nozzle 22. TOP NOZZLE SUBASSEMBLY Turning now to FIGS. 2 and 3, as well as FIG. 1, there is shown in greater detail the separate components making up the top nozzle 22 which is mounted on the upper end portions 24 of the guide thimbles 14 of the fuel assembly 10. The top nozzle 22 basically includes an upper hold-down plate 30, an enclosure 32 having a lower adapter plate 34 and an upstanding discontinuous sidewall 36 formed by a plurality of spaced upstanding wall portions 38 surrounding and attached to the periphery of the adapter plate, a plurality of sleeve members 40, comprising part of the features of the present invention to be described later, being disposed between the upper and lower plates 30,34, and a plurality of hold-down coil springs 42 extending between the upper and lower plates 30,34 and disposed in a manner to be described below relative to the sleeve members 40. The upper hold-down plate 30 has a plurality of passageways 44 defined therethrough, while the lower adapter plate has a plurality of openings 46, the passageways 44 and openings 46 being arranged in respective patterns which are matched to that of the guide thimbles 14 of the fuel assembly 10. More particularly, the upper end portions 24 of the guide thimbles 14 extend upwardly through the openings 46 in the lower adapter plate 34 and above the upper surface 48 thereof. A plurality of lower retainers 50 are attached, such as by brazing, to the guide thimbles 14 below the lower adapter plate 34 for limiting downward slidable movement of the adapter plate 34 relative to the guide thimbles 14 and thereby supporting the adapter plate on the guide thimbles with the upper end portions 24 thereof extending above the adapter plate. (The upper end portions 24 of the guide thimbles 14 contain the remaining features of the present invention to be described below.) Each lower retainer 50 on one guide thimble 14 has a series of scallops 52 formed on its periphery which are aligned with those of the fuel rods 18 grouped about the respective one guide thimble so that the fuel rods may be removed and replaced during reconstitution of the fuel assembly 10. Furthermore, the top nozzle 22 includes a plurality of upstanding bosses 54 having respective central bores 56 defined therethrough. The bosses 54 are disposed above the upper hold-down plate 30, and each boss is attached to the hold-down plate 30 such that its central bore 56 is aligned with a respective one of the passageways 44 of the hold-down plate. Additionally, each boss 54 is of a cross-sectional size adapted to interfit within one of a plurality of holes (not shown) formed in the upper core plate (not shown) which open at a lower side thereof. The upper circumferential edge 64 of each boss 54 is chamfered for mating with a complementarily chamfered edge (not shown) on the lower side of the upper core plate at the entrance to each of the holes defined therein. Edges having such shapes act as guiding surfaces which facilitate alignment and insertion of the respective bosses into the corresponding holes in the upper core plate during installation of the fuel assembly within the reactor core. As mentioned above, the hold-down coil springs 42 are disposed within the enclosure 32 and extend between the lower adapter plate 34 and the upper hold-down plate 30 and support the upper plate in a spaced relation above the lower plate at a stationary position in which the upper plate abuts the lower side of the upper core plate (not shown) with the upstanding bosses 54 interfitted within the holes of the upper core plate. Also, the upper hold-down plate 30 is composed of an array of hubs 68 and ligaments 70 which extend between and interconnect the hubs. Each of the hubs 68 has one of the passageways 44 defined therethrough. Furthermore, one boss 54 is disposed above and connected to each of the hubs 68 with the bore 56 of the boss aligned with the respective passageway 44 of the hub. Finally, the top nozzle 22 includes means interconnecting the spaced upper and lower plates 30,34 so as to accommodate movement of the lower plate 34 toward and away from the upper plate 30 upon axial movement of the guide thimbles 14 of the fuel assembly 10, such as due to thermal growth, toward and away from the upper core plate (not shown). Also, the interconnecting means is effective to limit movement of the lower adapter plate 34 away from the upper hold-down plate 30 so as to maintain the springs 42 in a state of compression therebetween. In particular, the interconnecting means includes a plurality of lugs 72 connected to and extending downwardly from peripheral ones of the ligaments 70. The lugs 72 are respectively coupled to the upstanding wall portions 38 of the discontinuous sidewall 36 of the enclosure 32. Specifically, a generally vertical slot 74 is formed in each wall portion 38 and opens at the upper end thereof. A removable locking pin 76 is inserted horizontally into the upper end of the wall portion 38 to close the upper end of the slot 74 and a pin 78 mounted in the lower end of each lug 72 extends into the slot 74 below the locking pin 76 for slidable movement therealong as the upper and lower plates 30,34 move relative to one another. In such arrangement, the locking pin 76 and the lower end of the slot 74 respectively define the limits of movement of the lower adapter plate 34 toward and away from the upper hold-down plate 30. ARRANGEMENT FOR ATTACHING AND REATTACHING TOP NOZZLE IN RECONSTITUTABLE FUEL ASSEMBLY Referring now to FIGS. 4 to 9, there is shown the features of the arrangement for attaching and reattaching the top nozzle, generally designated 80, which together constitute the present invention. Specifically, these features include, first, the elongated sleeve members 40 of which one is shown disposed relative to one of the hold-down coil springs 42 between the upper and lower plates 30,34 and, second, complementary means, generally indicated at 82, on each of the sleeve members and the guide thimble upper end portions 24 which attach the top nozzle 22 and guide thimbles 14 together. Each sleeve member 40 includes an inner tubular alignment sleeve portion 84, an outer tubular shroud portion 86 and an intermediate annular flange portion 88. The inner alignment sleeve portion 84 is disposed within the coil spring 42, extends between plates 30,34 in alignment with the respective passageway 44 and opening 46 thereof, and receives the guide thimble upper end portion 24. Also, at its upper end 90 the inner sleeve portion 84 is inserted into the passageway 44 of the hold-down plate 30, while at its lower end 92 it rests on the adapter plate 34 adjacent the opening 46 therethrough. The outer tubular shroud portion 86 of the sleeve member 40 is disposed in concentric but outwardly spaced relation to the inner alignment sleeve portion 84, as clearly depicted especially in FIGS. 7 and 8. The outer shroud portion 86 has a lower end 94 resting on the adapter plate 34 also. From its lower end 94, the outer shroud portion 86 extends upwardly about a portion of the spring 42 for protecting the spring from damage by coolant cross flow from fuel assemblies located adjacent to the fuel assembly 10. The downward force of the spring 42 retains the sleeve member 40 in a generally stationary position upon and pressed against the adapter plate 34. The intermediate annular flange portion 88, which underlies the coil spring 42, extends between and interconnects the respective lower ends 92,94 of the inner sleeve and outer shroud portions 84,86. The intermediate flange portion 88, together with the lower end 92 of the inner tubular alignment sleeve portion 84 and the lower end 94 of the outer shroud portion 86 being connected to the flange portion, are all disposed in an unattached but contacting relationship with respect to the adapter plate 34 about the opening 46 therethrough. The complementary means 82 is formed on and interconnects the inner alignment sleeve portion 84 of each sleeve member 40 and the upper end portion 24 of each guide thimble 14 so as to attach the individual pairs of the sleeve member 40 and corresponding guide thimbles 14 together. The complementary means 82 includes serially arranged and spaced apart primary, secondary and tertiary annular grooves 96,98,100 formed circumferentially, such as by machining, on the interior 102 of the tubular alignment sleeve portion 84, with the primary groove 96 being located at the highest level and the tertiary groove 100 at the lowest level on the sleeve portion interior. Further, the complementary means 82 includes a progressive series of primary, secondary and tertiary interior sections 104,106,108 on the interior 102 of the alignment sleeve portion 84 which respectively contain the primary, secondary and tertiary annular grooves 96,98,100. The secondary and tertiary sections 106,108 are formed, such as by machining, on the interior 102 relative to the primary section 104 so as to provide regions of increasing relief immediately below each preceding groove. More particularly, the secondary section 106, being disposed below the primary section 104, has an interior diameter larger than that of the primary section, whereas the tertiary section 108, being disposed below the secondary section 106, has an interior diameter larger than that of the secondary section. As will be explained below, these regions of increasing relief on the interior 102 of the alignment sleeve portion 84 facilitate subsequent reconnections of the alignment sleeve portion and the respective guide thimble 14 together after reconstitution of the fuel assembly 10. Finally, the complementary means 82 also includes a primary exterior (360-degree) circumferential bulge 110 (see FIG. 4) formed on the guide thimble upper end portion 24, by a suitable bulging tool which fits within the guide thimble. The primary bulge 110 extends into the primary annular groove 96 so as to rigidly connect the sleeve member 40 and guide thimble 14 together. After an upper segment 112 of the guide thimble upper end portion 24 has been severed (see FIG. 5), by any suitable internal cutter, followed by removal and replacement of the top nozzle 22 at the initial reconstitution of the fuel assembly 10, the secondary groove 98 will receive a secondary exterior bulge 114 formed on the guide thimble upper end portion 24 in the same way as the primary bulge 110. If there should occur a second reconstitution of the fuel assembly 10 (which is unusual), then the tertiary groove 100 will receive a tertiary exterior bulge (not shown). The tertiary bulge would be formed on the guide thimble upper end portion 24 in the same way as the primary and secondary bulges 110,114, after severance of a second upper segment of the upper end portion, which now would contain the secondary bulge 114, followed by removal and receipt of the twice severed guide thimble upper end portion 24 from and back in the alignment sleeve portion 84, for reconnection of the alignment sleeve portion 84 and the twice severed guide thimble 14 together. The purpose for the presence of the relieved secondary and tertiary sections on the interior 102 of the alignment sleeve portion 84 of the sleeve member 40 is to facilitate subsequent insertion of the severed end of the guide thimble 14 back into the sleeve portion. To explain, when a bulge-type joint is made, the material immediately above and below the bulge is pushed radially outward into contact with the outside member (in this case, the sleeve portion). Since this causes plastic deformation of the material, the outside diameter of the guide thimble annular part being bulged from inside the thimble is permanently expanded by about 2 to 5 mils on the diameter immediately above and below the bulge. Therefore, to aid in reinserting the severed upper end portion 24 of the guide thimble 14 into the alignment sleeve portion 84 of the member 40, the sleeve portion is relieved radially outward below each bulge-receiving groove, as best seen in FIG. 9. It would be difficult, if not impossible, to reinsert the severed guide thimble back into the sleeve portion 84 without these relieved sections. It should be noted that 45-degree inward and upward tapered transitions 116,118,120 respectively interconnect the primary, secondary and tertiary sections 104,106,108 with the next lower, relieved section so that there is no hangup when lowering the top nozzle 22 back on the guide thimbles 14. To summarize, the steps carried out in attaching and reattaching the top nozzle 22 to the guide thimbles 14 of the reconstitutable fuel assembly 10 are depicted in FIGS. 4 to 6. In FIG. 4, the guide thimble upper end portion 24 has been inserted into the alignment sleeve portion 84 which includes at least the upper primary and lower secondary annular grooves 96,98 and an annular part of the upper end portion 24 internally formed by a suitable conventional tool as the primary exterior bulge 110. The primary bulge 110 extends outwardly into the primary annular groove 96 in the alignment sleeve portion 84 so as to connect the sleeve member 40 and guide thimble 14 together. Then, as seen in FIG. 5, when initial reconstitution of the fuel assembly 10 is desired, by using a suitable conventional internal cutter, the guide thimble upper end portion 24 is circumferentially cut at a location below the level of its annular part 110 bulged into the upper primary annular groove 96 but above the level of the lower secondary annular groove 98, for instance approximately at the location of the first transition 116 between the primary and secondary sections 104,106. In such manner, the upper segment 112 of the guide thimble upper end portion 24 which contains the primary bulged annular part 110 is severed from the remainder of the guide thimble 14. It will be noted that this segment 112 remains rigidly attached within the sleeve portion 84 and because of its position will not interfere (see FIG. 6) when the top nozzle 22 is reinserted back on the guide thimble 14. By using another suitable fixture, such as disclosed in the third patent application cross-referenced above, the top nozzle, including the alignment sleeve 84 with upper guide thimble segment 112 connected thereto, can be removed from the severed guide thimble upper end portion 24 for exposing the fuel rods 18 of the fuel assembly 10 for reconstitution. Note that there are no loose parts and the hold-down plate 30, hold-down springs 42 and sleeve members 40 remain in place on the removed top nozzle 22. After reconstitution of the fuel assembly 10, the same fixture is used to reinsert the top nozzle 22 back on the severed upper end portion 24 of each guide thimble 14 such that the severed upper end portions are received into the sleeve members 40. Then, as seen in FIG. 6, another upper annular part (secondary bulge 114) of each severed guide thimble upper end portion 24 is bulged outwardly from its interior into the secondary annular groove 98 in the alignment sleeve portion 84 so as to reconnect the sleeve member 40 and guide thimble 14 together. It is thought that the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.
060884207	summary	BACKGROUND OF THE INVENTION The present invention relates to a reactor core which is applied to a water cooling reactor, and in particular, to a reactor core which has improvements in core internal structural materials, fuel design and core arrangement structure. In general, a light water reactor, which is a water cooling reactor, is classified into a boiling water reactor and a pressurized water reactor. A number of fuel assemblies are charged in a reactor core of a boiling water reactor in four groups. In each fuel assembly, a fuel coating cladding) tube is filled with a fissile material as a nuclear fuel, and a heat generated by a nuclear reaction of the fissile material is removed by a coolant. A water is used as a coolant for removing the heat in the light water reactor. Hydrogen contained in water has a high neutron moderation ability, and therefore, the conventional water cooling reactor has a high ratio of water, and a high energy neutron (fast neutron) generated by the nuclear fission is greatly moderated. Thus, a low-energy thermal neutron (slow neutron) occupies most of neutrons. In the case where the fissile material absorbs the low-energy neutron, a fissile reaction of newly generating about three neutrons is not caused, but a ratio of a neutron capture of absorbing the neutrons in an atomic nucleus without causing the nuclear fission, becomes great. Therefore, the number of neutrons generated per neutron absorption is reduced in the nuclear fission reaction by a low-energy neutron. On the other hand, in a high-energy neutron (fast neutron), since a ratio of neutron capture reaction is low and the fissile reaction is great, two or more average neutrons per neutron absorption can be generated inclusive of the neutron capture effect. One of two or more fast neutrons newly generated is used for maintaining chain reaction, and on the other hand, the reminder thereof is absorbed in a parent material (nuclear material) such as .sup.238 U (U-238), thus, a fissionable material being effectively produced. In a case where a ratio of production and annihilation of the fissionable material is 1 or more, it has been found that fuel breeding is performed and a resource energy can be secured. This is the reason why various countries have made a research and development of a breeder reactor which newly produces fissionable materials by a speed more than the development of consuming a nuclear material. However, in a conventional water cooling reactor, the ratio of water, which is coolant, to fuel ranges from about 2.0 to 2.5, and accordingly, a fast neutron generated by a fissile reaction is moderated, and then, becomes a low energy. Thus, the breeding is not performed, and a ratio of production and annihilation of the fissile material was 1 or less, for example, a value of about 0.5. Therefore, in a breeder reactor, an uranium resource, which can be theoretically converted into a thermal energy at 100%, has mot been effectively utilized, and the uranium resource effectively utilized has been merely about 1%. In the case of making use of a high-energy spectral neutron, in the conventional large-scale fast breeder reactor, there is the possibility that a reactivity (void reactivity) becomes positive due to the boiling of a coolant. However, in a water cooling reactor, it is important to make negative the void reactivity in view of stability and safety of a reactor core. SUMMARY OF THE INVENTION An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art described above and to provide a reactor core capable of increasing a breeding ratio and improving a utilization factor of an uranium fuel. An another object of the present invention is to provide a reactor core which has a breeding ratio of at least about 1 to improve a utilization factor of an uranium resource and which can hold a void reactivity at a negative value so as to achieve an environmental protection and to further improve stability and reliability of a reactor core. A further object of the present invention is to provide a reactor core which has a breeding ratio of at least about 1 so that a utilization factor of the uranium resource is 100 time as much as a conventional reactor core and which can hold a void reactivity at a negative value so as to improve stability and economy of the reactor core, even if the reactor core has the same diametrical direction size as that of a conventional reactor core. These and other objects can be achieved according to the present invention by providing, in one aspect, a reactor core including a number of fuel assemblies charged therein, wherein each of the fuel assemblies comprises a fuel bundle in which adjacent fuel rods are arranged so as to provide a triangular shape and a ratio of a coolant channel cross section to a fuel cross section is set to be 1 or less. In this aspect, the fuel assemblies have an arrangement pitch of about 300 mm or more. The fuel assembly is composed of a cylindrical channel box and the fuel bundle disposed in the channel box and having substantially square cross section, the channel box being provided with a protrusion (projection) for removing a coolant at an outer side thereof. The fuel assembly is composed of a cylindrical channel box and the fuel bundle disposed in the channel box, the channel box being provided with a support pad at an upper portion thereof in an operating state so as to mutually support adjacent fuel assemblies in a transverse direction. The fuel bundle may be constructed in a manner that a number of fuel rods are arranged and held by means of a grid-shape spacer so as to provide a triangular shape. The grid-shape spacer is provided with grid and a spring means attached to the grid for preventing vibration of the fuel. The vibration preventive spring and the grid are formed integrally with each other, and the grid is formed of a stainless steel or inconell. The fuel bundle may be formed by assembling in a bundle a number of fuel rods each having a fuel cladding tube filled with a fuel material by means of a fuel spacer and at least either one of the channel box and the fuel cladding tube is formed of a stainless steel. Pultonium and recovery uranium are used as the fuel material. The fuel assemblies comprise at least a normal fuel assembly and a partial fuel assembly having an exothermic portion length shorter than that of the normal fuel assembly, and the fuel assembly has an exothermic portion of a maximum length of 2 m or less and the partial fuel assembly has an exothermic portion of a maximum length of 1 m or less. The normal fuel assembly has upper and lower portions to which shaft brackets are provided and the partial fuel assembly has upper and lower portions to at least one of which a shaft bracket is not provided. In another aspect, there is provided a reactor core including a number of fuel assemblies each having a cylindrical channel box and a fuel bundle disposed therein, wherein a control rod is further provided between the fuel assemblies or in the fuel assembly to be freely withdrawal, the control rod being provided with a control rod absorber having a hollow follower at upper or lower portion thereof for preventing a coolant from flowing when the control rod is withdrawn. In this aspect, the fuel assemblies have an arrangement of four fuel assemblies adjacent to each other and the control rod has a cross-shaped cross section and is disposed between the four fuel assemblies so as to be freely withdrawal from a lower side thereof, the control rod being formed with a follower at an upper portion thereof which forms a coolant removal space, and a ratio of the number of control rods to the number of fuel assemblies charged in the reactor core is set to be substantially 1:1. In a further aspect, there is provided a reactor core including a number of fuel assemblies charged therein, wherein the fuel assemblies comprise a normal fuel assembly having a predetermined fuel effective exothermic portion and a partial fuel assembly having an exothermic portion having a length shorter than that of the normal fuel assembly, the partial fuel assembly being provided, at an upper portion thereof, with a hermetic container which is filled with a sealed gas. In this aspect, the hermetic container is formed of aluminum, zirconium or zircaloy having a small neutron absorption cross section. The fuel assembly is composed of a cylindrical channel box and a fuel bundle disposed in the channel box, the fuel bundle including a plurality of fuel rods and being provided with a coolant removal rod at a central portion between adjacent three or four fuel rods. The coolant removal rod has an inner hollow structure, and the coolant removal rod is formed of aluminum, zircaloy or zirconium having a small neutron absorption cross section. The fuel assembly is provided with a support pad disposed at four corner portions of an upper portion of the channel box so as to ride on each of the corner portions from an outer side thereof and upper portions of adjacent fuel assemblies are supported by means of the support pads in a transverse direction. The fuel assembly is composed of a cylindrical channel box and a fuel bundle disposed in the channel box, the fuel bundle including a number of fuel rods formed into a bundle by means of a fuel spacer so as to provide a triangular shape, the channel box being provided with an inner side portion covering the fuel bundle, and a protrusion which corresponds to unevenness of an outer periphery of the fuel bundle is formed to the inner side portion of the channel box. The channel box is provided with an outer side portion to which a protrusion for removing a coolant is formed. In a still further aspect, there is provided a reactor core including a number of fuel assemblies charged therein, wherein the fuel assemblies are composed of cylindrical channel boxes each having an inner space being divided into a normal fuel element region and a partial fuel element region by means of a coolant channel partition wall. The normal fuel element region is formed so that a normal fuel element having a predetermined fuel effective length is arranged and the partial fuel element region is formed so that a short-dimension fuel element having a fuel effective length shorter than that of the normal fuel element is arranged and a distribution of coolant flow rate to the normal fuel element region and the partial fuel element region is carried out by means of an orifice provided on a lower portion of the fuel assembly. According to the present invention of the characters and structures mentioned above, the fuel pins constituting the fuel bundle are arranged so as to provide a triangular shape, so that the arrangement density of fuel pins can be improved. Further, the ratio of the coolant channel cross section to the fuel cross section is set to 1 or less, which is considerably smaller as compared with the conventional ratio, so that the average neutron energy can be made close to the sodium cooling water type fast breeder reactor. As a result, a ratio of neutron capture reaction of the fissionable material is small, and the number of neutrons generated per neutron absorption is increased. Thus, the number of neutrons absorbed in the parent material becomes much, so that the breeding ratio can be set to about 1, and also, a utilization factor of uranium resource can be greatly improved. The arrangement pitch of the fuel assembly is about 300 mm or more so that the fuel assembly has a large diameter. Accordingly, it is possible to lower the ratio of water in the gap between the fuel assemblies to the overall volume and to lower the ratio of water to fuel, so that the breeding ratio can be increased. The channel box is provided with the protrusion (projection) at the outer side thereof, so that the water removal space is ensured in the reactor core and the ratio of water to fuel can be lowered and also provided with the support pad at the upper portion thereof, so that the upper lattice plate can be dispensed and the gap between the fuel assemblies can be made small. Therefore, the fuel volume ratio is increased, and the ratio of water to fuel is lowered, thus increasing the breeding ratio. Since the fuel bundle housed in the channel box is supported by means of the grid spacer so that fuel rods are arranged to provide a triangular shape, the fuel assembly is safely secured and the fuel rods are closely arranged. Thus, the fuel volume ratio is increased and the ratio of water to fuel is increased, also increasing the breeding ratio. Since the grid of the grid spacer is provided with the vibration preventive spring and the fuel rod is elastically and stably held by means of the vibration preventive spring, the fuel assembly can be safely secured. Further, the grid and the vibration preventive spring are formed integrally with each other, and thereby, the number of components can be reduced, and molding process is easily performed. Since the grid is formed of stainless steel or inconell, the grid can be made thin and mechanical and physical strength can be sufficiently maintained even if the grid is made thin. Since at least one of the channel box and the fuel coating tube is formed of stainless steel, the wall thickness is made thin, and the fuel volume ratio is increased, and the ratio of water to fuel is lowered to increase the breeding ratio. Since plutonium and recovery uranium are used as the fuel material, the number of neutron generated from materials other than plutonium can be increased, thus increasing the breeding ratio. Since the normal fuel assembly and the partial fuel assembly are arranged, in the case where the output power of reactor core raises up to increase the void reactivity, the neutron generated in the reactor core leaks out on the upper portion (or lower portion) of the reactor core through the streaming path, so that the void reactivity can be made negative. Therefore, inherent stability and environmental protection can be achieved. Since the normal fuel assembly has a maximum exothermic portion of the length which is 2 m or less, and the partial fuel assembly has a maximum exothermic portion of the length which is 1 m or less, even if the reactor core has the same core diametrical direction size as the conventional light water cooling reactor, the void reactivity can be made negative. Since the normal fuel assembly is provided with the shaft brackets so as to absorb the neutron leaking from the reactor core and, on the other hand, the shaft bracket is not provided on at least one of upper and lower portions of the partial fuel assembly so as to increase the neutron leakage when the void reactivity increases, whereby the breeding ratio can be increased and the void reactivity can be made negative even if the reactor core has the same core diametrical direction size as the conventional reactor core. Therefore, environmental protection, safety and reliability can be improved. Since the control rod is provided with a hollow follower for preventing a coolant from flowing into the reactor core when being taken out, it is possible to lower the ratio of water in the gap between fuel assemblies or the gap in the fuel assemblies to the overall volume and the ratio of water to fuel is lowered, thus increasing the breeding ratio. The control rod having a cross-shaped cross section is provided between four fuel assemblies adjacent to each other so as to be freely withdrawal from the lower portion thereof, and each control rod is formed with a follower which forms a water removal space at the upper portion thereof, and further, a ratio of the number of control rods to the number of fuel assemblies charged in the reactor core is set so as to be substantially 1:1. Accordingly, the fuel assembly has a large diameter, and the fuel volume ratio is increased and the ratio of water to fuel is lowered, so that the breeding ratio can be increased to at least about 1. Since the partial fuel assembly is provided with a hermetic container which is filled with a sealed gas, at the upper portion thereof, the streaming path is formed on the upper portion of the partial fuel assembly so that the leakage of neutron in the axial direction of the reactor core can be facilitated. Therefore, the breeding ratio is increased, and simultaneously, the void reactivity is lowered, so that the void reactivity can be made negative. Since the hermetic container provided on the upper portion of the partial fuel assembly is formed of aluminum, zirconium or zircaloy having a small neutron absorption cross section, the neutron absorption in the hermetic container is decreased and the neutron absorption of U-238 of the nuclear material is relatively increased, so that the breeding ratio can be increased and the void reactivity can be lowered. Since the coolant removal rod is provided on the gap between the fuel rods of the fuel assembly, the coolant can be removed by means of the coolant removal rod, and the volume ratio of water to fuel is decreased, so that the void reactivity can be lowered. Since the coolant removal rod has an inner hollow structure, the neutron absorption is decreased by the coolant removal rod, and the neutron is relatively absorbed in the nuclear material such as U-238, so that the breeding ratio can be increased and the void reactivity can be lowered. Further, the coolant removal rod is formed of aluminum, zircaloy or zirconium having a small neutron absorption cross section, so that the breeding ratio can be further increased and the void reactivity can be lowered. Since the support pads are provided at four corner portions of the upper portion of the cylindrical channel box so as to ride on each corner portion from an outside portion thereof, and the upper portions of the adjacent fuel assemblies are supported by means of the support pads in a transverse direction, this serves to eliminate a reactor core lattice plate. The gap between the fuel assemblies is made narrow, and as a result, the fuel volume ratio is increased and the breeding ratio can be increased. The void reactivity can be lowered. Further, the support pad serves to previously prevent the fuel assemblies from being in contact with each other and to secure a gap for inserting the control rod. The fuel bundle housed in the fuel assembly is constructed in a manner that a number of fuel rods are made into a bundle by means of a fuel spacer so as to provide a triangular shape, and an inner side of the channel box is provided with a protrusion. Accordingly, the fuel rods are closely arranged, and the fuel volume ratio is increased. On the other hand, the protrusion serves to lower the ratio of coolant to fuel, so that the breeding ratio can be increased and the void reactivity can be lowered. Since the outer side of the channel box is provided with a protrusion, in addition to the inner side thereof, the ratio of water to fuel is further lowered, so that the breeding ratio can be increased and the void reactivity can be lowered. The upper portion of the partial fuel element region is voided and the streaming path of neutron is formed, so that the void reactivity can be lowered and made negative. The distribution of coolant flow rate to the normal fuel element region and the partial fuel element region is properly carried out by means of an orifice provided on an lower portion of the fuel assembly. The nature and further characteristic features will be made more clear from the following descriptions made with reference to the accompanying drawings.
	claims	1. A method of controlling a two-bank multileaf collimator (MLC) of a radiation treatment delivery system, comprising:determining a plurality of radiation beam delivery positional sections to contain MLC leaf control instructions while a radiation beam is active, wherein each of the plurality of radiation beam delivery positional sections corresponds to a range of radiation beam positions over a discrete time interval, wherein the discrete time interval constrains an overall treatment time;generating a plurality of openings for each of the plurality of radiation beam delivery positional sections, each of the plurality of openings corresponding to one of a plurality of leaf pairs of the MLC, wherein two or more of the plurality of openings correspond to different widths;generating a plurality of leaf open-time fractions for each of the plurality of radiation beam delivery positional sections, each of the plurality of leaf open-time fractions corresponding to one of the plurality of leaf pairs of the MLC; andcontrolling, by a processing device, the plurality of leaf pairs of the MLC such that each leaf pair of the plurality of leaf pairs is opened to a corresponding opening of the plurality of openings for a corresponding leaf open-time fraction of the plurality of leaf open-time fractions during the discrete time interval corresponding to the range of radiation beam positions, while the radiation beam of the radiation treatment system is active. 2. The method of claim 1, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction. 3. The method of claim 2, wherein the different direction remains constant while the different position follows a linear trajectory that sweeps the radiation beam over a length of a treatment target. 4. The method of claim 2, wherein the different directions are non-coplanar. 5. The method of claim 2, wherein the plurality of openings and the plurality of leaf open-time fractions form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. 6. The method of claim 1, wherein two or more of the plurality of leaf open-time fractions during the discrete time interval are different. 7. The method of claim 1, wherein the plurality of openings conform to an outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of the plurality of leaf pairs within the MLC. 8. The method of claim 1, wherein the range of radiation beam positions is along an arc of a gantry of the radiation treatment system. 9. The method of claim 8, wherein the arc corresponds to approximately seven degrees of gantry rotation. 10. A radiation treatment delivery system, comprising:a linear accelerator (LINAC) to output a radiation beam at a distal end;a multileaf collimator (MLC), coupled with the distal end of the LINAC, wherein the MLC has two banks of leaves, organized into a plurality of opposing leaf pairs; anda processing device, operatively coupled to the LINAC and the MLC, to:control the plurality of leaf pairs of the MLC such that for each of a plurality of radiation beam delivery positional sections corresponding to a range of radiation beam positions over a discrete time interval, wherein the discrete time interval constrains an overall treatment time and wherein each leaf pair of the plurality of opposing leaf pairs is open to a fixed opening for a fraction of time in the discrete time interval and closed for the remaining fraction of time in the discrete time interval, while the radiation beam of the radiation treatment system is active. 11. The system of claim 10, wherein the MLC is an electromagnetically actuated multileaf collimator (eMLC). 12. The system of claim 10, wherein the LINAC is mounted on a rotating gantry, and wherein radiation beams delivered from the range of radiation beam positions rotate around a treatment target. 13. The system of claim 12, wherein the treatment target is moved axially through a bore of the rotating gantry, and wherein the radiation beams delivered from the range of radiation beam positions follow a helical path about the treatment target. 14. The system of claim 10, wherein the LINAC and the MLC are mounted on a robotic arm, and wherein the radiation beam delivered from the range of radiation beam positions is non-coplanar. 15. The system of claim 10, wherein the fixed opening and the fraction of time form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. 16. The system of claim 10, wherein the fixed opening conforms to the outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of plurality of leaf pairs within the MLC. 17. The system of claim 10, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction, and wherein the at least one of: the different position or the different direction follows a helical trajectory about a treatment target. 18. The system of claim 10, wherein the system is a helical radiation treatment delivery system. 19. The system of claim 10, wherein the system is a robotic-based LINAC radiation treatment system. 20. The system of claim 10, wherein the system is gantry-based radiation treatment delivery system. 21. A non-transitory computer readable medium comprising instructions that, when executed by a processing device of a radiation treatment delivery system, cause the processing device to:generate a plurality of radiation beam delivery positional sections to contain MLC leaf control instructions while a radiation beam is active, wherein each of the plurality of radiation beam delivery positional sections corresponds to a range of radiation beam positions over a discrete time interval, wherein the discrete time interval constrains an overall treatment time;generate a plurality of openings for each of the plurality of radiation beam delivery positional sections, each of the plurality of openings corresponding to one of a plurality of leaf pairs of the MLC;generate a plurality of leaf open-time fractions for each of the plurality of radiation beam delivery positional sections, each of the plurality of leaf open-time fractions corresponding to one of the plurality of leaf pairs of the MLC; andcontrol, by the processing device, the plurality of leaf pairs of the MLC such that each leaf pair of the plurality of leaf pairs is opened to a corresponding opening of the plurality of openings for a corresponding leaf open-time fraction of the plurality of leaf open-time fractions during the discrete time interval corresponding to the range of radiation beam positions, while the radiation beam of the radiation treatment system is active. 22. The non-transitory computer readable medium of claim 21, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction. 23. The non-transitory computer readable medium of claim 22, wherein the at least one of: the different position or the different direction follows a helical trajectory about a treatment target. 24. The non-transitory computer readable medium of claim 22, wherein the different direction remains constant while the different position follows a linear trajectory that sweeps the radiation beam over a length of a treatment target. 25. The non-transitory computer readable medium of claim 22, wherein the different directions are non-coplanar. 26. The non-transitory computer readable medium of claim 21, wherein the plurality of openings and the plurality of leaf open-time fractions form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. 27. The non-transitory computer readable medium of claim 21, wherein the plurality of openings conform to an outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of the plurality of leaf pairs within the MLC. 28. The non-transitory computer readable medium of claim 21, wherein the range of radiation beam positions is along an arc of a gantry of the radiation treatment system. 29. The non-transitory computer readable medium of claim 28, wherein the arc corresponds to approximately seven degrees of gantry rotation.
052672891	claims	1. A method for enhancing the wear resistance of a tubular component of a nuclear fuel assembly, comprising: supporting the component in an implantation chamber; removing ambient air from the chamber; generating a plasma plume of positively charged metal source material by establishing an electrical discharge arc which travels from a cathode of said source material to an anode of a different material; passing at least a portion of the plasma plume through an electromagnetic duct which filters constituents other than free, high energy source material ions out of the plume; and directing the high energy source material positive ions through the chamber onto the negatively charged component. the ionic compound implants in the component. generating a cathodic arc plasma of the source material; filtering the plasma to remove neutral atoms and macroparticles; and directing the ions of the filtered plasma onto the component. the component is surrounded by a reactive gas; and the filtered plasma passes through the reactive gas to produce metal compound ions that implant in the component. 2. The method of claim 1, wherein the chamber is backfilled with a reactive gas which forms an ionic compound with the source material ions, and 3. The method of claim 2, wherein the reactive gas is nitrogen. 4. The method of claim 3, wherein the source material is one of Zr, Ti, Ta, Hf. 5. The method of claim 4, wherein the source material is one of Zr or Ti. 6. The method of claim 1, wherein the component is a zirconium alloy cladding tube for a nuclear fuel rod. 7. The method of claim 1, wherein the component is a zirconium alloy control rod guide tube. 8. A method for treating nuclear fuel assembly components by ion implantation of a metal source material to enhance wear resistance, wherein the improvement comprises; 9. The method of claim 8, wherein 10. The method of claim 9, wherein the reactive gas is nitrogen. 11. The method of claim 8, wherein the component is a zircaloy alloy and the source material is one of Zr or Ti. 12. A zircaloy alloy nuclear fuel assembly component having wear enhancing material implanted from a cathodic arc of filtered plasma to a depth of approximately 2.0 .mu.m in the component. 13. The component of claim 12, wherein the enhancing material is a nitride.
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050900447	abstract	For performing an X-ray examination wherein a catheter is inserted into a blood vessel of a subject from the brachial region, an X-ray shield is mounted on an arm rest to shield scattered X-rays passed from the subject, to thereby protect operator's hands handling the catheter.
051981831	abstract	The apparatus of the present invention is a plate of neutron absorbing material. The plate may have a releasable locking feature permitting the plate to be secured within a nuclear fuel assembly between nuclear fuel rods during storage or transportation then removed for further use or destruction.. The method of the present invention has the step of placing a plate of neutron absorbing material between nuclear fuel rods within a nuclear fuel assembly, preferably between the two outermost columns of nuclear fuel rods. Additionally, the plate may be releasably locked in place.
	abstract	An X-ray beam conditioning device that has a crystal holder and a motor is provided. The crystal holder supports a first crystal block and a second crystal block, each of which diffracts X-ray by a specific diffraction angle. The motor can rotate the crystal holder around an axis extending at right angles to a plane including an optical axis of X-ray and can fixedly support the crystal holder at the rotated position. The crystal holder holds the first and second crystal blocks at such angles to each other such that both crystal blocks diffract X-ray. The optical axes of the two crystal blocks can be adjusted by rotating the crystal holder about the axis, that is, the only one axis.
047456310	description	As may be seen in the drawing FIGURE, a source 1 of x-rays generates x-rays which through a collimating slit 2 defines a coarse fan beam 4 of x-rays. The slit is formed in a plane of x-ray absorbant material 3 and placed for directing the fan beam 4 onto a flying spot generator 5. The flying spot generator 5 consists of an even number of helical shaped x-ray windows 6' and 6", for example, which have been provided in a cylindrical shell 5. The cylindrical shell 5 is of x-ray opaque material, such as lead. A practical device, however, could be formed of three concentric cylindrical shells in which an inner core is a shell of aluminum or other low x-ray absorbing material, an intermediate shell is of lead with the lead completely machined away in the requisite helical pattern, and an outer shell or cover of thin, low x-ray absorbing stainless steel. This arrangement could be approximately 12 inches long and 4 inches in diameter, and supported in a manner to permit rotation around its length. Such rotation may be at 3600 rpm with the support being by way of splitrace roller bearings along its length. The split helical pattern permits transmission of x-rays. The number of x-ray windows 6' and 6" need to be of an even number, such as the two illustrated in the drawing FIGURE. The windows are slits of a helical shape on opposite sides of the cylindrical shell, and the flying spot 10 appears when the two helixes 6' and 6" intersect in the field of an incident x-ray beam. Upon rotation of the shell the flying spot 10 transmitted through the flying spot generator 5 moves in a linear directon 13 from one end of the flying spot generator to the opposite end. Because of this movement of the flying spot, a single detector 7 is provided to detect an object 8 moving along a conveyor belt 9. The conveyor belt movement is in the direction 11, for example. The detector 7 could be a single wire, long, high pressure gas counter tube. Such an arrangement might be filled with xenon and operated in a current measuring mode with a gas gain of the order of 10.sup.2 to 10.sup.4. The detector 7 could also be a photomultiplier with a long scintillator. In this arrangement, an object 8 passing on the belt 9 would move through the moving flying spot which would pass back and forth over the object. The rotation of the shell or flying spot generator 5 generates the linear motion of the x-ray flying spot which passes along the detector 7. Image formation is retrieved from the detector by electronically sampling the detector signal and correlating the time of sampling with the angular position of the rotating shell. In a practical arrangement of the present invention, the helical windows 6' and 6" in the flying spot generator 5 are x-ray windows passing x-radiation. However, modifications to use gamma ray radiation, or other radiation, are also suitable. While a single arrangement of the present invention has been illustrated and described, the present invention includes all variations and features which may be evident from the claims.
042740355	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 is a view for explaining one embodiment of a field emission electron gun according to this invention. As shown in the figure, a control electrode 12 is disposed in the vicinity of a cathode 11. Electrons emitted from the cathode 11 are focused into a beam 19 by an electron optics lens 16 through an anode 13 and is projected on a sample 17. All the components are installed in a vacuum vessel 18. The cathode 11 and the control electrode 12 are insulated by an insulator 21, and they are respectively led into an insulating transformer by high-tension cables. A D.C. power supply 15 and a switch 14 are installed inside the insulated transformer. By the change-over of the switch 14, the control electrode 12 can be connected with either ground potential at position B or the same potential as that of the cathode 11 at position A. When the control electrode 12 is connected with ground potential, the energy of the electron beam to be emitted from the cathode 11 is equal to a drawing-out voltage applied by the D.C. power supply 15 (for example, about 5 kV) and becomes low energy. When the control electrode 12 is connected with the same potential as that of the cathode 11, an electric field at the tip of the cathode is concealed by the control electrode 12, and no field emission occurs. In order to cause the field emission, the voltage of the D.C. power supply 15 is increased. The energy of the electron beam to be emitted at that time becomes high energy (for example, about 10 kV or above). In this manner, even when the high supply voltage is increased, the energy of the electron current can be made high without the emission of any high current. The magnitude of the high energy can be determined as desired, depending upon the mutual positions or shapes of the cathode 11 and the control electrode 12. More specifically, by vertically moving a device which supports the cathode 11, for example, bellows 20, it is possible to vary the mutual positions of the cathode 11 and the control electrode 12 and to change the value of the high energy as desired. FIG. 3 illustrates the ratio between the high energy and the low energy at the time when the inside diameter (D) of the cylindrical control electrode 12 and the position (L) of the cathode 11 relative to the control electrode 12 are varied. In the figure, the abcissa indicates the ratio of L/D, while the ordinate indicates the ratio of V.sub.H /V.sub.L. Here, V.sub.L denotes a voltage in the case where an emission current of, for example, approximately 10 .mu.A is emitted when the control electrode is made the ground potential. V.sub.H denotes a voltage in the case where the emission current of, for example, approximately 10 .mu.A is emitted when the control electrode is made the same potential as that of the cathode. As understood from the diagram, by externally changing the position of the control electrode 12, with respect to the cathode, it is possible to obtain an electron beam of any desired energy (in this embodiment, above approximately 5 kV). Needless to say, this invention is not restricted to the various numerical values and shapes employed in the above description of the embodiment, but appropriate values and shapes can be selected depending upon set conditions. Although, in the foregoing embodiment, the length L is varied by making the cathode movable relative to the control electrode, it is also possible to vary the length L by making the control electrode movable relative to the cathode. As set forth above, according to this invention, the position of the cathode or that of the control electrode is made variable externally of the vacuum, thereby making it possible to obtain the electron beam of any desired high energy. It is possible to change-over the electron beams of low energy and high energy with the very simple construction consisting of the single switch and the single high-voltage source, and the handling is also simple which is very advantageous. Further, with this invention, which can vary the irradiation energy of the electron beam most simply, an electron microscope of high resolving power can be fabricated. It is understood that the present invention is not limited to the details shown and described herein but is susceptible to numerous changes and modifications as known to those skilled in the art such that the present invention is intended to cover all such changes and modifications as are encompassed by the scope of the appended claims.
	claims	1. A comprehensive joint technology-based apparatus for treatment of a uranium-contaminated soil, the apparatus comprising:an electrokinetic remediation system including a cathode zone and an anode zone set at both sides of the uranium-contaminated soil, and a cathode and an anode disposed respectively in the cathode and anode zones, the cathode and anode being respectively connected to a power transformer with wires;an elution system including a plurality of sprinklers disposed between the cathode zone and the anode zone forming an array;a pumping system including a pumping well disposed in a vicinity of the cathode zone, with a pumping pipeline therein, wherein the pumping pipeline, a pump and a pumping controller are connected to a water collecting sump sequentially;a soil storage tank disposed adjacent to the water collecting sump;a remediation-separation system having one end connected to the soil storage tank and water collecting sump, with another end connected a soil recovery tank, a ground water recovery tank and a uranium recovery tank;a recharge system including a recharge well set in a vicinity of the anode zone, with a recharge pipeline therein; andan inductively coupled plasma atomic emission spectrometer (ICP-AES) configured to measure residual uranium;wherein the recharge pipeline, and a recharge pump are connected to the ground water storage tank sequentially,wherein the sprinklers are used to spray an eluting solution to the contaminated soil,wherein the eluting solution is a 0.2-0.6 M citric acid solution or a sodium bicarbonate solution, andwherein the remediation-separation system is configured to form a uranyl hydroxide deposit from a suspension containing a uranium compound by illuminating the suspension with fluorescent light;wherein the pumping pipeline and the recharge pipeline are approximately 0.95 m in depth across a phreatic layer; and the cathode and anode are inserted approximately 12 m in depth into the contaminated soil, tangent with the phreatic layer, such that a uranium removal efficiency of at least 80.2% is achieved with an eluting duration of 3 h and an eluting solution volume in soil of 30 ml/g. 2. The apparatus of claim 1, further comprising:a catholyte processing system; andan anolyte processing system,the catholyte processing system including a catholyte storage compartment, a catholyte pH controller and a peristaltic pump;wherein the catholyte pH controller is connected to the catholyte storage compartment, while the catholyte storage compartment is connected to the cathode zone through a corresponding pipeline and a peristaltic pump;the anolyte processing system including an anolyte storage compartment, an anolyte pH controller and a peristaltic pump;the anolyte pH controller is connected to the anolyte storage compartment, while the anolyte storage compartment is connected to the anode zone through the corresponding pipeline and the peristaltic pump. 3. The apparatus of claim 1, wherein the remediation-separation system comprises:a photoelectric remediation device,a screen,a solid phase extraction device,an aqueous phase processing device, anda solid phase processing device;wherein one end of the photoelectric remediation device is connected to the water collecting sump and the soil storage tank, and another end is connected to the screen;wherein the screen is respectively connected to the aqueous phase processing device and the solid phase extraction device;the aqueous phase processing device is connected to the ground water recovery tank; the solid phase extraction device is connected to the solid phase processing device and the uranium recovery tank;the solid phase processing device is connected to the soil recovery tank. 4. The apparatus of claim 1, wherein the pumping pipeline and the recharge pipeline are both non-sand concrete tube wells having an inner diameter of about 250-500 mm and a depth of about 35-50 m, and a periphery filled with backfill and gravels, with a filling layer of about 60-100 mm in thickness. 5. A method for use with the apparatus of claim 1, the method comprising:Step 1: installing the comprehensive joint technology-based apparatus for treatment of uranium-contaminated soil at a site contaminated by uranium;Step 2: spraying an eluting solution via multiple sprinklers to the soil until the concentration of eluting solution in the soil is 10-30 ml/g;Step 3: adding the catholyte and anolyte respectively in the cathode zone and the anode zone, and maintaining a voltage between the cathode and anode of 150-600V via the power transformer; keeping the electrokinetic remediation for 2-8 days, and then uranium substances will migrate to the vicinity of anode, leading to gathering of uranium pollutants;Step 4: during the electrokinetic remediation, starting up the pump to transport contaminated ground water in a phreatic layer to the water collecting sump through the pumping pipeline, with the pumping volume of 5-10 m3/h and lasting for 1.5-6 days;Step 5: if the electrokinetic remediation is finished, excavating the soil in the area within the diameter of 1-2.5 m and the depth of 10-20 m centered on the anode zone, and then transport it to the soil storage tank;Step 6: transporting the contaminated soil in the soil storage tank and the contaminated water in the water collecting sump to the remediation-separation system, and mix the soil and ground water to form a suspension; adjust the pH of the suspension to 2.8-3.5, and irradiate the suspension with fluorescent light for 24-36 h for photolysis remediation, to thereby have a uranium compound in the suspension become a uranyl hydroxide deposit; after the photolysis remediation, separate the soil, water, and the uranyl hydroxide deposit, and respectively transport them to the soil recovery tank, the ground water recovery tank and the uranium recovery tank;Step 7: transporting the soil remedied through the photolysis in the soil recovery tank (16) to the vicinity of the anode zone, and start up the recharge pump to transport the remedied ground water in the ground water recovery tank to the recharge well via the recharge pipeline;Step 8: testing the soil remediation effect with the ICP-AES, and repeating Step 1 to Step 7 if needed until the uranium in the soil meets the requirement of the safety standards or is totally removed;wherein after Step 1, the pumping pipeline and the recharge pipeline are approximately 0.95 m in depth across a phreatic layer; and the cathode and anode are inserted approximately 12 m in depth into the contaminated soil, tangent with the phreatic layer, such that a uranium removal efficiency of at least 80.2% is achieved with an eluting duration of 3 h and an eluting solution volume in soil of 30 ml/g. 6. The method of claim 5, wherein a weight/volume ration of soil and ground water in the suspension in Step 6 is 1 g:(10-20) ml. 7. The method of claim 5, wherein the separation of soil, water and uranyl hydroxide in Step 6 is achieved as follows:when the photolysis remediation is finished, solid substances and the solution in the suspension are separated through the screen having openings with a diameter of about 0.22 micron;transporting the obtained ground water through the separation to the aqueous phase processing device to adjust a neutral pH, and then transporting it to the ground water recovery tank;transporting the obtained soil to the solid phase extraction device to recover the uranyl hydroxide precipitate in the soil with the use of the TBP-sulfonated kerosene extraction technique, and then transporting the recovered uranium substances to the uranium recovery tank; andtransporting remaining soil to the solid phase processing device to adjust a neutral pH, and then transport it to the soil recovery tank.
	summary
041359747	summary	BACKGROUND OF THE INVENTION This invention pertains to structural support systems for the core of a nuclear reactor and more particularly to such support systems which are subject to both thermal perturbations and radiation induced swelling; as with liquid metal fast breeder reactors (LMFBR). The primary restraint on the design of the core support system for an LMFBR is that the system must accurately and predictably position the fuel assemblies while causing a negative overall power coefficient of reactivity. Such a design is particularly difficult to achieve since thermal perturbations and radiation induced swelling constantly change the positional relationship of the structural elements. The prior art basically discloses two contrasting approaches to this problem. The first approach features a relatively loose core, to wit, one in which the fuel assemblies are allowed to bow and other structural elements are allowed to freely change their positional relationship. The operating characteristics of the reactor are then predictable on the basis of the ultimate positional relationship of the elements at operating temperature. The EBR-II nuclear reactor is an example of this approach. The second approach features a tight core which restricts bowing, of which Fermi is an example. However, these present designs preceded the recognition of the degree to which radiation induced swelling effects the positional relationship of the structural elements of the core and its support system, and accordingly, the above examples made insufficient allowance for the resulting problems. SUMMARY OF THE INVENTION In accordance with this invention, a relatively restricted nuclear core is achieved at operating conditions while sufficient clearance between fuel assemblies at refueling temperature is obtained through the application of metals with different coefficients of thermal expansion, careful choice of fuel assembly dimensions, clearances, spacer pad locations and the application of a temperature compensated radial restraint system. The core of an LMFBR is generally cylindrical in shape and made-up of hexagonal fuel assemblies surrounded by similarly shaped blanket and reflector assemblies. Control rod assemblies are interspersed throughout the core. The core may be positioned between an upper and lower core support structure. The individual assemblies may also be fitted with springs to take up differential thermal expansion and keep the fuel assemblies positively positioned relative to the core support. A typical core assembly may consist of an array of individual fuel rods surrounded by a hexagonal can having a plurality of raised spacer pads distributed along its length. The fuel assemblies are fitted with nozzles at either end. These nozzles fit into receptacles in the upper and lower core support structures and a coil take-up spring may be used at the lower end of the fuel assemblies to compensate for differential thermal expansion. In accordance with this invention, a relatively restricted core is achieved which will allow adequate clearance upon refueling by providing a plurality of structural elements which maintain positional predictability under conditions of thermal perturbations and radiation induced swelling. The structural elements utilized include core plates of a different metal from that of the fuel assemblies such that refueling clearances are closed due to differential thermal expansion, a double lower core support plate structure which maintains the fuel assemblies in a vertical or nearly vertical position even when the upper core plate is removed, spacer pads positioned and displaced laterally from each other a predetermined amount such that the gaps are closed as the reactor approaches power, a radial restraint system utilizing relatively compliant springs with spring like back-up members strategically located outside of the active fuel zone and support columns for the upper and lower core plates which bend to allow movement of same.
051204886	claims	1. A sealing sleeve for sealing a leak in a pipe or pipe socket in a nuclear reactor, which pipe or pipe socket in repair position has an open end for receiving said sealing sleeve which is intended to sealingly surround said pipe or pipe socket on each side of said leak, wherein the sleeve comprises a mid-portion defining a bellows and annular ends, said bellows being made of memory metal having an original shape and a suitable transient temperature, wherein at a temperature above the transient temperature said annular ends define a first diameter which is suitable for achieving sealing around the pipe or pipe socket on each side of the leak, and wherein at a temperature below the transient temperature, the ends define a second diameter permitting the sleeve to be freely fitted onto the pipe or pipe socket, said sleeve in a fitted position being intended to be subjected to heating to a temperature above the transient temperature in order to achieve the desired sealing by the memory metal striving to recover its original shape, said sleeve being able to withstand dimensional changes in the pipe or pipe socket due to temperature variations in the nuclear reactor between +40.degree. C. and +280.degree. C. 2. A sealing sleeve according to claim 1, wherein said annular ends around the inside of the sleeve are provided with a bulge or a plurality of grooves. 3. A sealing sleeve according to claim 1, wherein the interior of the sleeve at each end is provided with sealing rings of stainless steel, the outer limiting surface of each of which is spherical and has an outer diameter which sealingly fits within the inner diameter of the sleeve at a temperature below the transient temperature, and said rings of stainless steel having an inner diameter permitting the sleeve to be freely fitted over the pipe or the pipe socket. 4. A sealing sleeve according to claim 1, wherein the sleeve is internally provided with an eccentric sealing ring, at one end. 5. A sealing sleeve according to claim 1, wherein said annular ends are a first end having a first end diameter, and a second end having a second end diameter which is smaller than the first end diameter, said sleeve being able to seal a connection between two pipes having two different diameters. 6. A sealing sleeve for sealing a leak in a pipe or pipe socket in a nuclear reactor, which pipe or pipe socket in repair position has an open end for receiving said sealing sleeve which is intended to sealingly surround said pipe or pipe socket on each side of said leak, wherein the sleeve comprises a mid-portion defining a bellows and annular ends, said bellows being made of stainless steel and provided at the ends with fitted-on rings of a memory metal having an original shape and a suitable transient temperature, said annular ends of the sleeve having a first diameter and said rings having a first inner diameter with a suitable mounting clearance in relation to the pipe or pipe socket to be sealed which pipe or pipe socket has a first outer diameter, said rings being given a second inner diameter at a temperature above the transient temperature of the memory metal which is chosen to be sufficiently smaller than said first outer diameter of the pipe or pipe socket such that in an applied position of the sleeve around said pipe or pipe socket sealing is achieved, said rings thereafter at a temperature below the transient temperature being extended into a third diameter suitable for pressing the rings onto said ends, said sleeve being able to withstand dimensional changes in the pipe or pipe socket due to temperature variations in the nuclear reactor between +40.degree. C. and +280.degree. C. 7. A sealing sleeve according to claim 6, wherein the sleeve at one opening is internally provided with an eccentric sealing ring of stainless steel having a diameter which enables the stainless steel ring to fit within the first inner diameter of the sleeve. 8. A sealing sleeve according to claim 6, wherein said annular ends are a first end having a first end diameter, and a second end having a second end diameter which is smaller than the first end diameter, said sleeve used for sealing a connection between two pipes having two different diameters.
	abstract	With a view to providing a beam diaphragm having a large maximum value of aperture opening under a limited profile dimension, the beam diaphragm comprises a pair of control rings having coaxial apertures for the passage of X-rays therethrough and being opposed to each other axially through a spacing and coaxially rotatable independently of each other, a blade positioned between the pair of control rings, and position adjusting means which, in accordance with a relative rotation of the pair of control rings, causes the blade to move toward or away from a common axis of the apertures so as to describe a sectorial plane whose radius increases or decreases continuously.
	abstract	A quality degradation point estimating method for estimating a quality degradation point in a directed link set through which a communication flow passed is provided. The quality degradation point estimating method has: (A) determining a test flow set for estimating a quality degradation point; and (B) estimating the quality degradation point in the directed link set by sending the test flow set to the network. The (A) step includes a step of setting the flow, which passes through a partial set as a part of the directed link set, as the test flow and adding the set test flow to the test flow set. The test flow is sent from the test terminal on the network to a predetermined node in the partial set. A response is obtained at the predetermined node, and the response is sent from the predetermined node to a predetermined terminal.
	claims	1. An X-ray condenser for condensing X-rays radiated from an X-ray source, comprising: parallel beam forming means for forming X-rays radiated from said X-ray source to parallel X-ray beams; a zone plate provided on a downstream side of said parallel beam forming means in a propagating direction of the X-rays and constructed by alternately arranging a plurality of X-ray transmitting bands and X-ray shielding bands; and an analyzing crystal provided between said parallel beam forming means and said zone plate, for selecting X-rays having a specific wavelength from X-rays containing a plurality of X-ray components having different wavelengths. 2. An X-ray condenser as claimed in claim 1 , further comprising a casing for air-tighly enclosing said parallel beam forming means and said zone plate and evacuation means for discharging air in said casing. claim 1 3. An X-ray condenser as claimed in claim 1 , wherein said parallel beam forming means is parabolic parallel beam forming means having parabolic surfaces, for forming diverging X-ray beams to parallel X-ray beams either horizontally or vertically by utilizing said parabolic surfaces. claim 1 4. An X-ray condenser as claimed in claim 1 , wherein said parallel beam forming means is parabolic parallel beam forming means having a pair of parabolic surfaces juxtaposed with each other, for forming diverging X-ray beams to parallel X-ray beams both horizontally and vertically by utilizing said parabolic surfaces. claim 1 5. An X-ray condenser as claimed in claim 3 , wherein said parallel beams forming means is a parabolic reflection mirror capable of reflecting X-ray by a parabolic surface or a parallel multi-layered film mirror capable of diffracting X-ray by a multi-layered film formed on a parabolic surface thereof. claim 3 6. An X-ray condenser as claimed in claim 4 , wherein said parallel beam forming means is a parabolic reflection mirror capable of reflecting X-ray by a parabolic surface or a parallel multi-layered film mirror capable of diffracting X-ray by a multi-layered film formed on a parabolic surface thereof. claim 4 7. An X-ray condenser as claimed in claim 4 , wherein said X-ray source is a point focus X-ray source having an X-ray focus point having an area defined by a horizontal side length substantially the same as a vertical side length. claim 4 8. An X-ray diffraction apparatus including an X-ray source, an X-ray condenser for condensing X-rays radiated from said X-ray source to a micro-point of a specimen or a micro-specimen and X-ray detection means for detecting X-rays from said specimen, wherein said X-ray condenser comprises: parallel beam forming means for forming X-rays radiated from said X-ray source to parallel X-ray beams; a zone plate provided on a downstream side of said parallel beam forming means in a propagating direction of the X-rays and constructed by alternately arranging a plurality of X-ray transmitting bands and X-ray shielding bands; and an analyzing crystal provided between said parallel beam forming means and said zone plate, for selecting X-rays having a specific wavelength from X-rays containing a plurality of X-ray components having different wavelengths. 9. An X-ray diffraction apparatus as claimed in claim 8 , further comprising a casing for air-tightly enclosing said parallel beam forming means and said zone plate and evacuation means for discharging air in said casing. claim 8 10. An X-ray diffraction apparatus as claimed in claim 8 , wherein said parallel beam forming means is parabolic parallel beam forming means having parabolic surfaces, for forming diverging X-ray beams to parallel X-ray beams either horizontally or vertically by utilizing said parabolic surfaces. claim 8 11. An X-ray diffraction apparatus as claimed in claim 8 , wherein said parallel beam forming means is parabolic parallel beam forming means having a pair of parabolic surfaces juxtaposed with each other, for forming diverging X-ray beams to parallel X-ray beams both horizontally and vertically by utilizing said parabolic surfaces. claim 8 12. An X-ray diffraction apparatus as claimed in claim 10 , wherein said parallel beam forming means is a parabolic reflection mirror capable of reflecting X-rays by a parabolic surface or a parallel multi-layered film mirror capable of diffracting X-rays by a multi-layered film formed on a parabolic surface thereof. claim 10 13. An X-ray diffraction apparatus as claimed in claim 11 , wherein said parallel beam forming means is a parabolic reflection mirror capable of reflecting X-rays by a parabolic surface or a parallel multi-layered film mirror capable of diffracting X-rays by a multi-layered film formed on a parabolic surface thereof. claim 11 14. An X-ray diffraction apparatus as claimed in claim 11 , wherein said X-ray source is a point focus X-ray source having an X-ray focus point having an area defined by a horizontal side length substantially the same as a vertical side length. claim 11
	description	This application is a U.S. national phase under the provisions of 35 U.S.C. §371 of International Patent Application No. PCT/EP12/53134 filed Feb. 24, 2012, which in turn claims priority of French Patent Application No. 1151610 filed Feb. 28, 2011. The disclosures of such international patent application and French priority patent application are hereby incorporated herein by reference in their respective entireties, for all purposes. This invention relates to a method for precipitating one or more solutes contained in a liquid phase. It has applications in the treatment and recycling of spent nuclear fuel, for which it is particularly advantageous for oxalic preparation of actinides that can occur after a nuclear fuel treatment process, particularly in order to retrieve uranium and plutonium currently present in spent fuels. More precisely, the spent nuclear fuel treatment process may comprise several cycles and particularly three purification cycles after the conventional steps to remove the cladding and dissolution in concentrated nitric acid, namely: a first cycle aimed at jointly decontaminating uranium and plutonium of two actinides(III), americium and curium, and the majority of fission products, and creating a partition of uranium and plutonium into two flows; and two complementary cycles called the “second uranium cycle” and “second plutonium cycle” respectively, aimed at purifying uranium and plutonium separately after their partition. The plutonium thus isolated is then subjected to an oxalic precipitation step to give a precipitate of plutonium oxalate Pu(C2O4)2, and this precipitate can then be transformed into plutonium oxide. One of the difficulties of precipitation methods and particularly the oxalic precipitation method lies in the sticky nature of the precipitate, part of which can stick to the walls of the reactor in which the precipitation reaction takes place. Precipitation methods according to prior art can be used in many types of reactors. Simple design reactors may include crystalliser type reactors and vortex type reactors. Crystalliser type reactors are based on the principle of a progressive increase in supersaturation of the precipitation solution leading to a crystallisation of the solute to be precipitated, this type of reactor conventionally operating in discontinuous mode which limits their use in the context of making a precipitation at industrial scale. One solution to overcome this disadvantage is to increase the number of reactors and have them function in parallel and at different times. Vortex type reactors, like those defined for example in U.S. Pat. No. 3,395,988 and U.S. Pat. No. 4,464,341, are conventionally composed of a glass receptacle, the content of which is stirred by rotation of a rod inside it that creates a vortex with two functions, namely to keep the precipitate in an aqueous phase and away from the glass walls and to guarantee sufficient residence time for the growth of precipitate grains to make them less sticky. However, these reactors periodically get clogged and it is difficult to guarantee sub-critical conditions when the sizes of these reactors have to be increased. Reactors with a more complex design have also been envisaged, including so-called “pulsed column” reactors as disclosed in FR 2905283 that use a pulsed counter-current system and confinement of the precipitate by an organic phase in an internally lined column, however with the following limitations: the use of an inner liner for the column necessary to set up shear and to create contact with reagents significantly increases the area exposed to the precipitate, which can nevertheless cause adhesion of the precipitate to the exposed surface if the lining surface is not systematically coated with highly hydrophobic materials; the use of a pulsed counter-current system creates dead zones in the column, on which drops can bond to the lining of the column, thus creating a precipitate deposit. Therefore there is a need for a method of precipitating one or more solutes without the following disadvantages: bonding of the precipitate formed at the reactor walls, eventually generating clogging of the reactor; the obligation to coat the reactor walls with a hydrophobic coating to limit the bond of the precipitate on the walls; appearance of dead zones in the precipitation reactor leading to clogging of the reactor in these zones. The invention deals with a method for precipitating at least one solute in a reactor comprising: a) a step in which a first liquid phase comprising the solute and a second liquid phase comprising a solute precipitation reagent are brought into contact in co-current in a reactor, as a result of which a mix is obtained comprising precipitate particles in suspension, and a third liquid phase forming a dispersing phase for said mix; and b) a step in which the mix mentioned in step a) is fluidised by the third phase. The method according to the invention has the following advantages due to the inherent nature of these two steps: the lack of bond of the precipitate to the reactor walls due to confinement of the mix comprising particles of precipitate by a third liquid phase, and fluidisation of the mix by this same third liquid phase that prevents any stagnation of these particles at the walls and enables drops that enclose said particles to bounce off the surface of the walls; the possibility of optimising adjustment of the residence time of the mix in the reactor due to the flexibility of the fluidisation condition (particularly by varying the flow of the third liquid phase to obtain optimum precipitation of the solute), this residence time being chosen so as to obtain large sized precipitate grains such that they will not bond to the reactor walls; good usage flexibility with the possibility of adapting the method as a function of the solute(s) that is (are) to be precipitated by the appropriate choice of a second liquid phase and a third liquid phase, provided that they match the criteria according to the invention. As mentioned above, the method according to the invention includes a first step a) consisting of bringing a first liquid phase comprising the solute into contact with a second liquid phase comprising a solute precipitation reagent in co-current in a reactor, as a result of which a mix is obtained comprising precipitate particles in suspension, and a third liquid phase forming a dispersing phase for said mix. Advantageously, the first liquid phase and the second liquid phase are miscible with each other, while the third liquid phase is immiscible with the mix comprising the first liquid phase and the second liquid phase. Note that co-current means that the first liquid phase, the second liquid phase and the third liquid phase circulate in the same direction, which implies that they are injected into the reactor in a mode that enables this co-current circulation. Thus, from a practical point of view, particularly in the case in which the density of the mix of the first liquid phase and of the second liquid phase is greater than the density of the third liquid phase, the first liquid phase, the second liquid phase and the third liquid phase may be injected into a reactor, for example, in a lower part of the reactor, this lower part forming an injection zone. For example, the inlet of the first liquid phase and the inlet of the second liquid phase may be arranged at the same height in the injection zone and facing each other, such that these two phases come into contact immediately when they are injected simultaneously, thus spontaneously forming a mix comprising a suspension of precipitate particles. According to this configuration, the inlet of the third liquid phase may be in the injection zone below the inlets of the first liquid phase and the second liquid phase. If the density of the mix of the first liquid phase and of the second liquid phase is less than the density of the third liquid phase, the first liquid phase, the second liquid phase and the third liquid phase may be injected into a reactor, for example, in an upper part of the reactor, this upper part forming an injection zone. For example, the inlet of the first liquid phase and the inlet of the second liquid phase may be arranged at the same height in the injection zone and facing each other, such that these two phases come into contact immediately when they are injected simultaneously, thus spontaneously forming a mix comprising a suspension of precipitate particles. According to this configuration, the inlet of the third liquid phase may be in the injection zone above the inlets of the first liquid phase and the second liquid phase. The first liquid phase, the second liquid phase and the third liquid phase may be injected continuously or semi-continuously, in which a semi-continuous injection means that at least one of the above mentioned liquid phases is injected continuously and at least one of the above mentioned liquid phases is injected discontinuously (for example by periodic start-stop, ramp or Dirac type injection). Note that a dispersing phase means that the third liquid phase is such that the mix formed by bringing the first liquid phase into contact with the second liquid phase in which the precipitate is formed, is dispersed in the form of drops inside the third liquid phase, this third liquid phase usually being chosen so that it is immiscible with the mix resulting from the first liquid phase and the second liquid phase. The step to create contact a) is conventionally done by injection of a first liquid phase, a second liquid phase and a third liquid phase in a specific zone of the reactor, for example a lower part of said reactor (called the injection zone) or an upper part of said reactor, knowing that the supply flow of the third liquid phase should preferably be greater than the supply flow of the first liquid phase and/or the second liquid phase, so that the third liquid phase can fluidise the mix resulting from the first liquid phase and the second liquid phase. Furthermore, the choice of such a supply flow for the third liquid phase will also enable precipitate grains formed by reaction between the first liquid phase and the second liquid phase to not bond to the reactor walls. As mentioned above, the first liquid phase and the second liquid phase will react with each other during use of step a) to form a mix comprising a precipitate of the solute, this mix will then be entrained by the third liquid phase in the fluidised bed condition (corresponding to step b) mentioned above and also called fluidisation). Note that fluidisation means putting drops containing the formed precipitate particles into suspension into an upwards fluid flow, said drops containing particles forming the fluidised bed and the upwards fluid flow being composed of the third liquid phase. The use of a fluidised bed condition is the result particularly of an increase in the size of these particles which can also prevent these particles from bonding to the walls, in addition to the fact that this bond is also prevented by confinement generated by the third liquid phase. Apart from steps a) and b), the method may include a sedimentation step of the mix originating from step b), this sedimentation step possibly being done by simple settlement, this sedimentation step possibly being followed by a step to collect said precipitate. The collection step may typically be done by drawing off precipitate particles that have sedimented. This collection may be followed by solid-liquid separation operations such as filtration, centrifuging or other types of operations, so as to remove any liquid phase drawn off with the precipitated particles from the precipitated particles, and washing and/or drying operations. The method according to the invention may also include a recycling step of the third liquid phase, that can be re-injected in the injection zone mentioned above. The method according to the invention is advantageously used particularly in the case in which the density of the mix of the first liquid phase and the second liquid phase is more than the density of the third liquid phase, in a fluidised bed reactor with a vertical principal axis comprising: a lower part (also called the bottom part), used for injection of the first liquid phase, the second liquid phase and the third liquid phase; an intermediate part (also called the middle part) used for fluidisation of the mix resulting from the first liquid phase and the second liquid phase by the third liquid phase; and an upper part (also called the top part) used for sedimentation of the precipitate formed. Conversely, in the case in which the density of the mix of the first liquid phase and the second liquid phase is less than the density of the third liquid phase, the method may also advantageously be used in a fluidised bed reactor with a vertical principal axis comprising: an upper part (also called the top part) used for injection of the first liquid phase, the second liquid phase and the third liquid phase; an intermediate part (also called the middle part) used for fluidisation of the mix resulting from the first liquid phase and the second liquid phase by the third liquid phase; and a lower part (also called the bottom part) used for sedimentation of the precipitate formed. When the method according to the invention is dedicated to oxalic precipitation of the actinides, particularly for the treatment of spent fuels, the precipitate formed in the framework of this method is a precipitate of actinide oxalate(s). In this case: the first liquid phase is conventionally an aqueous solution comprising a solute including at least one actinide element (this solution being referred to as “actinide solution” in the following; the second liquid phase is conventionally an aqueous solution containing a precipitation reagent of the actinide element(s) present in the first liquid phase, this precipitation reagent being oxalic acid (this solution being referred to as an “oxalic solution” in the following; and the third liquid phase is conventionally an organic solution comprising an organic solvent immiscible with the first liquid phase and the second liquid phase, this organic solvent possibly being dodecane or hydrogenated tetrapropylene (known under the abbreviation HTP). The actinide solution conventionally contains the actinide(s) in the form of nitrate(s), since this is the form in which these elements are usually produced by spent nuclear fuel treatment plants. In particular, when the method according to the invention is used for the treatment of spent fuels, the actinides concerned may be uranium, plutonium, neptunium, thorium, americium and/or curium. In particular, they may be uranium, plutonium, neptunium, americium and/or curium, when the oxalate precipitates formed are intended to be transformed into a compound of actinide(s) that can be used for the fabrication of oxide, carbide or nitride type nuclear fuel pellets. The invention will now be described with regard to a particular embodiment described below, this embodiment being given for illustrative and non-limitative purposes. Reactor 1 shown diagrammatically in FIG. 1 is used for tests related to precipitation of cerium oxalate. This glass reactor with a vertical principal axis is composed of three parts: a lower part 3 forming the injection zone of the first liquid phase consisting of an aqueous solution comprising cerium in the form of cerium nitrate, the second liquid phase consisting of an oxalic solution and the third liquid phase consisting of an organic solution of hydrogenated tetrapropylene, this lower part being shown in detail in FIG. 2; an intermediate part 5 used to fluidise the emulsion mix formed from the first liquid phase and the second liquid phase by the third liquid phase, this intermediate part consisting of a cylindrical tube comprising a first vertical part 7 with a constant cross-section (15 mm diameter), with a curved part 9 and a second vertical part 11; an upper part 13 that will be used to recuperate the formed precipitate by sedimentation, consisting of a settlement tank into which the open end of the second vertical part 11 of the tube forming the intermediate part of the reactor is immersed. More precisely, the lower part shown in detail in FIG. 2 is composed of a cylindrical tube with a constant cross-section (15 mm diameter) closed at its lower end 15. The reagents, in other words the organic solution of hydrogenated tetrapropylene (forming the third liquid phase), the solution comprising cerium (forming the first liquid phase) and the oxalic solution (forming the second liquid phase) are introduced into this lower part via: a vertical nozzle 17 passing through the lower end of the tube and supplying the lower part of the reactor with an organic solution via a valve 18; two nozzles 19 and 21 located at mid-height of the injection zone and diametrically opposite each other, these nozzles 19 and 21 being composed of a horizontal glass tube starting from its inlet and finishing in the form of an elbow at the outlet (corresponding to the part of the nozzle that penetrates into the lower part of the reactor), these nozzles supplying the lower part of the reactor with oxalic solution and with a solution comprising cerium respectively. The lower part 3 of the reactor is also provided with a tube 23 at its lower end used to drain the reactor, this tube being connected to a conduit 25 fitted with a valve 27. The vertical nozzle 17 is connected to an organic solution supply tank 29 via a conduit 31 on which a pump 33 is mounted that can adjust the supply flow of the organic solution. The nozzles 19 and 21 are connected to an oxalic solution supply tank 35 and a tank supplying a solution containing cerium 37 via conduits 39 and 41 on which pumps 43 and 45 and valves 47 and 49 are also mounted, to adjust the supply flow of the oxalic solution and the solution containing cerium. The oxalic solution and the solution containing cerium are brought into contact in this lower part of the reactor, causing in situ generation of a precipitate of cerium oxalate within a mix of aqueous phases derived from the first and second liquid phases, this mix then being entrained towards the intermediate part of the reactor via the organic solution, which confines this mix within droplets dispersed in the organic solution. As can be seen in FIGS. 1 and 2, the reactor does not contain a stirrer, the different phases being mixed solely by the supply flows of these different phases into this reactor. As mentioned above, the intermediate part consists of a vertical cylindrical tube with a constant cross-section (15 mm diameter) that extends the tube forming the lower part of the reactor over a height of 1 m (thus forming a first vertical part) beyond which this tube is curved leading to a second vertical part, the end of which is immersed in the upper part of the reactor, the tube having the same section over its entire length. Finally, the upper part 13 of the reactor consists of a settlement tank with a grating 51 that forces coalescence of fines (corresponding to very small droplets) that can be entrained by the organic solution during the settlement operation, an outlet 53 fitted with a valve 55 in its narrowed lower part to evacuate the precipitate and that can also form a drain line of the settlement tank and an outlet 57 fitted with a valve 59 for evacuation of oxalic mother water. In the upper part, the settlement tank also comprises an overflow 61 through which the entire organic phase can be transferred to the organic phase tank 29 via a conduit 63. Three tests (A, B and C respectively) were carried out under sticking precipitation conditions starting from a first liquid phase (a nitrate aqueous solution (1.5 N) of cerium nitrate with a concentration of 24 g/L), a second liquid phase (an oxalic aqueous solution with a concentration of 0.7 mol/L) and a third liquid phase (an organic solution of hydrogenated tetrapropylene HTP). The first test A was done with the following liquid phase flows: 0.4 L/h of cerium nitrate (III); 0.4 L/h of oxalic acid; and 100 L/h of HTP. The plate shown in FIG. 3 taken at the intermediate part of the reactor (more precisely the first vertical part before the curved part) shows a relatively mono-dispersed distribution of droplets (resulting from the mix of the first liquid phase and the second liquid phase), in which the precipitate can be distinguished during its formation. The second test B is done by reducing the organic phase flow relative to test A, the corresponding flows of liquid phases being as follows: 0.4 L/h of cerium nitrate (III); 0.4 L/h of oxalic acid; and 80 L/h of HTP. The plate shown in FIG. 4 taken at the same reactor level as FIG. 3 shows the appearance of macrodrops in which the precipitate can be distinguished as it deposits inside the macrodrops. The third test C is done by further reducing the organic phase flow from the value in test B, the corresponding flows of the liquid phases being as follows: 0.4 L/h of cerium nitrate (III); 0.4 L/h of oxalic acid; and 60 L/h of HTP. On the plate shown in FIG. 5, it can be seen that macrodrops are beginning to collect and to become organised to form clusters of drops containing precipitates. These clusters form cyclically and delimit separate zones at which precipitation occurs. These clusters conventionally have a lower displacement speed than the macrodrops obtained with the organic solution and are entrained upwards according to a pure piston type flow. This mode is particularly interesting because it can give a stable confinement of precipitate clusters by the organic solution and a long residence time in the reactor. This operating mode can also absorb relatively high supply flows in the first liquid phase (the phase containing cerium nitrate). Thus, the following functional points have been observed for the appearance of precipitate clusters, for supply flows in the first liquid phase varying from 200 mL/h to 1000 mL/h: Supply flow inSupply flow inSupply flow inthe first liquidthe second liquidthe third liquidphase (in mL/h)phase (in mL/h)phase (in L/h)20020050-5540040055-6080080070-751000100080-85
	summary
	description	This application claims the benefit under 35 U.S.C. § 119(e) of the priority of the following U.S. Provisional Applications filed on Apr. 3, 2013, the entire disclosures of which are hereby incorporated by reference: U.S. Provisional Application No. 61/808,136, entitled “MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION POWER”; U.S. Provisional Application No. 61/808,122, entitled “MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION POWER”; U.S. Provisional Application No. 61/808,131, entitled “ENCAPSULATION AS A METHOD TO ENHANCE MAGNETIC FIELD PLASMA CONFINEMENT”; U.S. Provisional Application No. 61/807,932, entitled “SUPPORTS FOR STRUCTURES IMMERSED IN PLASMA”; U.S. Provisional Application No. 61/808,110, entitled “RESONANT HEATING OF PLASMA WITH HELICON ANTENNAS”; U.S. Provisional Application No. 61/808,066, entitled “PLASMA HEATING WITH RADIO FREQUENCY WAVES”; U.S. Provisional Application No. 61/808,093, entitled “PLASMA HEATING WITH NEUTRAL BEAMS”; U.S. Provisional Application No. 61/808,089, entitled “ACTIVE COOLING OF STRUCTURES IMMERSED IN PLASMA”; U.S. Provisional Application No. 61/808,101, entitled “PLASMA HEATING VIA FIELD OSCILLATIONS”; and U.S. Provisional Application No. 61/808,154, entitled “DIRECT ENERGY CONVERSION OF FUSION PLASMA ENERGY VIA CYCLED ADIABATIC COMPRESSION AND EXPANSION”. This disclosure generally relates to fusion reactors and more specifically to a system for supporting structures immersed in plasma. Fusion power is power that is generated by a nuclear fusion process in which two or more atomic nuclei collide at very high speed and join to form a new type of atomic nucleus. A fusion reactor is a device that produces fusion power by confining and controlling plasma. Certain components of a fusion reactor may be immersed in plasma. According to embodiments of the present disclosure, disadvantages and problems associated with previous techniques for supporting structures immersed in plasma may be reduced or eliminated. In some embodiments, a fusion reactor is disclosed. The fusion reactor includes an enclosure having a first end, a second end opposite the first end, and a midpoint substantially equidistant between the first and second ends of the enclosure. The fusion reactor includes two internal magnetic coils suspended within the enclosure and positioned on opposite sides of the midpoint of the enclosure, one or more encapsulating magnetic coils positioned on each side of the midpoint of the enclosure, two mirror magnetic coils positioned on opposite sides of the midpoint of the enclosure, and one or more support stalks for supporting the two internal magnetic coils suspended within the enclosure. The one or more encapsulating magnetic coils and the two mirror magnetic coils are coaxial with the internal magnetic coils. The magnetic coils are operable, when supplied with electric currents, to form magnetic fields for confining plasma within the enclosure. Certain embodiments of the present disclosure may provide one or more technical advantages. For example, in some embodiments the one or more support stalks may advantageously provide mechanical support, service, isolation, and shielding with little disturbance to the plasma environment. In some embodiments, the one or more support stalks may allow plasma to flow smoothly around with a minimum of interruption due to a smaller cross-section opposing the flow. The cross-section of the support stalks may be thinner in a direction orthogonal to the magnetic field, resulting in a minimum of plasma flux to the surface while providing stiffness in the direction of the field lines. As another example, in some embodiments the one or more support stalks may be coated to provide sputtering resistance to impacting plasma. In some embodiments, the one or more support stalks may have an internal cavity that may advantageously allow for power, cooling, and diagnostic lines, or other suitable components, to be drawn to structures within plasma, while at the same time isolating them from the plasma. Additionally, in some embodiments the internal cavities may contain current carrying wires for producing magnetic fields around the one or more support stalks, which may advantageously shield the one or more support stalks from impacting plasma. Certain embodiments of the present disclosure may include some, all, or none of the above advantages. One or more other technical advantages may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein. Embodiments of the present invention and its advantages are best understood by referring to FIGS. 1-13, like numerals being used for like and corresponding parts of the various drawings. Fusion reactors generate power by confining and controlling plasma that is used in a nuclear fusion process. Typically, fusion reactors are extremely large and complex devices. Because of their prohibitively large sizes, it is not feasible to mount typical fusion reactors on vehicles. As a result, the usefulness of typical fusion reactors is limited. The teachings of the disclosure recognize that it is desirable to provide a compact fusion reactor that is small enough to mount on or in vehicles such as trucks, trains, aircraft, ships, submarines, spacecraft, and the like. For example, it may be desirable to provide truck-mounted compact fusion reactors that may provide a decentralized power system. As another example, it may be desirable to provide a compact fusion reactor for an aircraft that greatly expands the range and operating time of the aircraft. In addition, it may desirable to provide a fusion reactor that may be utilized in power plants and desalination plants. The following describes an encapsulated linear ring cusp fusion reactor for providing these and other desired benefits associated with compact fusion reactors. FIG. 1 illustrates applications of a fusion reactor 110, according to certain embodiments. As one example, one or more embodiments of fusion reactor 110 are utilized by aircraft 101 to supply heat to one or more engines (e.g., turbines) of aircraft 101. A specific example of utilizing one or more fusion reactors 110 in an aircraft is discussed in more detail below in reference to FIG. 2. In another example, one or more embodiments of fusion reactor 110 are utilized by ship 102 to supply electricity and propulsion power. While an aircraft carrier is illustrated for ship 102 in FIG. 1, any type of ship (e.g., a cargo ship, a cruise ship, etc.) may utilize one or more embodiments of fusion reactor 110. As another example, one or more embodiments of fusion reactor 110 may be mounted to a flat-bed truck 103 in order to provide decentralized power or for supplying power to remote areas in need of electricity. As another example, one or more embodiments of fusion reactor 110 may be utilized by an electrical power plant 104 in order to provide electricity to a power grid. While specific applications for fusion reactor 110 are illustrated in FIG. 1, the disclosure is not limited to the illustrated applications. For example, fusion reactor 110 may be utilized in other applications such as trains, desalination plants, spacecraft, submarines, and the like. In general, fusion reactor 110 is a device that generates power by confining and controlling plasma that is used in a nuclear fusion process. Fusion reactor 110 generates a large amount of heat from the nuclear fusion process that may be converted into various forms of power. For example, the heat generated by fusion reactor 110 may be utilized to produce steam for driving a turbine and an electrical generator, thereby producing electricity. As another example, as discussed further below in reference to FIG. 2, the heat generated by fusion reactor 110 may be utilized directly by a turbine of a turbofan or fanjet engine of an aircraft instead of a combustor. Fusion reactor 110 may be scaled to have any desired output for any desired application. For example, one embodiment of fusion reactor 110 may be approximately 10 m×7 m and may have a gross heat output of approximately 100 MW. In other embodiments, fusion reactor 110 may be larger or smaller depending on the application and may have a greater or smaller heat output. For example, fusion reactor 110 may be scaled in size in order to have a gross heat output of over 200 MW. FIG. 2 illustrates an example aircraft system 200 that utilizes one or more fusion reactors 110, according to certain embodiments. Aircraft system 200 includes one or more fusion reactors 110, a fuel processor 210, one or more auxiliary power units (APUs) 220, and one or more turbofans 230. Fusion reactors 110 supply hot coolant 240 to turbofans 230 (e.g., either directly or via fuel processor 210) using one or more heat transfer lines. In some embodiments, hot coolant 240 is FLiBe (i.e., a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2)) or LiPb. In some embodiments, hot coolant 240 is additionally supplied to APUs 220. Once used by turbofans 240, return coolant 250 is fed back to fusion reactors 110 to be heated and used again. In some embodiments, return coolant 250 is fed directly to fusion reactors 110. In some embodiments, return coolant 250 may additionally be supplied to fusion reactors 110 from APUs 220. In general, aircraft system 200 utilizes one or more fusion reactors 110 in order to provide heat via hot coolant 240 to turbofans 230. Typically, a turbofan utilizes a combustor that burns jet fuel in order to heat intake air, thereby producing thrust. In aircraft system 200, however, the combustors of turbofans 230 have been replaced by heat exchangers that utilize hot coolant 240 provided by one or more fusion reactors 110 in order to heat the intake air. This may provide numerous advantages over typical turbofans. For example, by allowing turbofans 230 to operate without combustors that burn jet fuel, the range of aircraft 101 may be greatly extended. In addition, by greatly reducing or eliminating the need for jet fuel, the operating cost of aircraft 101 may be significantly reduced. FIGS. 3A and 3B illustrate a fusion reactor 110 that may be utilized in the example applications of FIG. 1, according to certain embodiments. In general, fusion reactor 110 is an encapsulated linear ring cusp fusion reactor in which encapsulating magnetic coils 150 are used to prevent plasma that is generated using internal cusp magnetic coils from expanding. In some embodiments, fusion reactor 110 includes an enclosure 120 with a center line 115 running down the center of enclosure 120 as shown. In some embodiments, enclosure 120 includes a vacuum chamber and has a cross-section as discussed below in reference to FIG. 7. Fusion reactor 100 includes internal coils 140 (e.g., internal coils 140a and 140, also known as “cusp” coils), encapsulating coils 150, and mirror coils 160 (e.g., mirror coils 160a and 160b). Internal coils 140 are suspended within enclosure 120 by any appropriate means and are centered on center line 115. Encapsulating coils 150 are also centered on center line 115 and may be either internal or external to enclosure 120. For example, encapsulating coils 150 may be suspended within enclosure 120 in some embodiments. In other embodiments, encapsulating coils 150 may be external to enclosure 120 as illustrated in FIGS. 3A and 3B. In general, fusion reactor 100 provides power by controlling and confining plasma 310 within enclosure 120 for a nuclear fusion process. Internal coils 140, encapsulating coils 150, and mirror coils 160 are energized to form magnetic fields which confine plasma 310 into a shape such as the shape shown in FIGS. 3B and 5. Certain gases, such as deuterium and tritium gases, may then be reacted to make energetic particles which heat plasma 310 and the walls of enclosure 120. The generated heat may then be used, for example, to power vehicles. For example, a liquid metal coolant such as FLiBe or LiPb may carry heat from the walls of fusion reactor 110 out to engines of an aircraft. In some embodiments, combustors in gas turbine engines may be replaced with heat exchangers that utilize the generated heat from fusion reactor 110. In some embodiments, electrical power may also be extracted from fusion reactor 110 via magnetohydrodynamic (MHD) processes. Fusion reactor 110 is an encapsulated linear ring cusp fusion device. The main plasma confinement is accomplished in some embodiments by a central linear ring cusp (e.g., center coil 130) with two spindle cusps located axially on either side (e.g., internal coils 140). These confinement regions are then encapsulated (e.g., with encapsulating coils 150) within a coaxial mirror field provided by mirror coils 160. The magnetic fields of fusion reactor 110 are provided by coaxially located magnetic field coils of varying sizes and currents. The ring cusp losses of the central region are mitigated by recirculation into the spindle cusps. This recirculating flow is made stable and compact by the encapsulating fields provided by encapsulating coils 150. The outward diffusion losses and axial losses from the main confinement zones are mitigated by the strong mirror fields of the encapsulating field provided by encapsulating coils 150. To function as a fusion energy producing device, heat is added to the confined plasma 310, causing it to undergo fusion reactions and produce heat. This heat can then be harvested to produce useful heat, work, and/or electrical power. Fusion reactor 110 is an improvement over existing systems in part because global MHD stability can be preserved and the losses through successive confinement zones are more isolated due to the scattering of particles moving along the null lines. This feature means that particles moving along the center line are not likely to pass immediately out of the system, but will take many scattering events to leave the system. This increases their lifetime in the device, increasing the ability of the reactor to produce useful fusion power. Fusion reactor 110 has novel magnetic field configurations that exhibit global MHD stability, has a minimum of particle losses via open field lines, uses all of the available magnetic field energy, and has a greatly simplified engineering design. The efficient use of magnetic fields means the disclosed embodiments may be an order of magnitude smaller than typical systems, which greatly reduces capital costs for power plants. In addition, the reduced costs allow the concept to be developed faster as each design cycle may be completed much quicker than typical system. In general, the disclosed embodiments have a simpler, more stable design with far less physics risk than existing systems. Enclosure 120 is any appropriate chamber or device for containing a fusion reaction. In some embodiments, enclosure 120 is a vacuum chamber that is generally cylindrical in shape. In other embodiments, enclosure 120 may be a shape other than cylindrical. In some embodiments, enclosure 120 has a centerline 115 running down a center axis of enclosure 120 as illustrated. In some embodiments, enclosure 120 has a first end 320 and a second end 330 that is opposite from first end 320. In some embodiments, enclosure 120 has a midpoint 340 that is substantially equidistant between first end 320 and second end 330. A cross-section of a particular embodiment of enclosure 120 is discussed below in reference to FIG. 8. Some embodiments of fusion reactor 110 may include a center coil 130. Center coil 130 is generally located proximate to midpoint 340 of enclosure 120. In some embodiments, center coil 130 is centered on center line 115 and is coaxial with internal coils 140. Center coil 130 may be either internal or external to enclosure 120, may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. Internal coils 140 are any appropriate magnetic coils that are suspended or otherwise positioned within enclosure 120. In some embodiments, internal coils 140 are superconducting magnetic coils. In some embodiments, internal coils 140 are toroidal in shape as shown in FIG. 3B. In some embodiments, internal coils 140 are centered on centerline 115. In some embodiments, internal coils 140 include two coils: a first internal coil 140a that is located between midpoint 340 and first end 320 of enclosure 120, and a second internal coil 140b that is located between midpoint 340 and second end 330 of enclosure 120. Internal coils 140 may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. A particular embodiment of an internal coil 140 is discussed in more detail below in reference to FIG. 7. Encapsulating coils 150 are any appropriate magnetic coils and generally have larger diameters than internal coils 140. In some embodiments, encapsulating coils 150 are centered on centerline 115 and are coaxial with internal coils 140. In general, encapsulating coils 150 encapsulate internal coils 140 and operate to close the original magnetic lines of internal coils 140 inside a magnetosphere. Closing these lines may reduce the extent of open field lines and reduce losses via recirculation. Encapsulating coils 150 also preserve the MHD stability of fusion reactor 110 by maintaining a magnetic wall that prevents plasma 310 from expanding. Encapsulating coils 150 have any appropriate cross-section, such as square or round. In some embodiments, encapsulating coils 150 are suspended within enclosure 120. In other embodiments, encapsulating coils 150 may be external to enclosure 120 as illustrated in FIGS. 3A and 3B. Encapsulating coils 150 may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. Fusion reactor 110 may include any number and arrangement of encapsulating coils 150. In some embodiments, encapsulating coils 150 include at least one encapsulating coil 150 positioned on each side of midpoint 340 of enclosure 120. For example, fusion reactor 110 may include two encapsulating coils 150: a first encapsulating coil 150 located between midpoint 340 and first end 320 of enclosure 120, and a second encapsulating coil 150 located between midpoint 340 and second end 330 of enclosure 120. In some embodiments, fusion reactor 110 includes a total of two, four, six, eight, or any other even number of encapsulating coils 150. In certain embodiments, fusion reactor 110 includes a first set of two encapsulating coils 150 located between internal coil 140a and first end 320 of enclosure 120, and a second set of two encapsulating coils 150 located between internal coil 140b and second end 330 of enclosure 120. While particular numbers and arrangements of encapsulating coils 150 have been disclosed, any appropriate number and arrangement of encapsulating coils 150 may be utilized by fusion reactor 110. Mirror coils 160 are magnetic coils that are generally located close to the ends of enclosure 120 (i.e., first end 320 and second end 330). In some embodiments, mirror coils 160 are centered on center line 115 and are coaxial with internal coils 140. In general, mirror coils 160 serve to decrease the axial cusp losses and make all the recirculating field lines satisfy an average minimum-β, a condition that is not satisfied by other existing recirculating schemes. In some embodiments, mirror coils 160 include two mirror coils 160: a first mirror coil 160a located proximate to first end 320 of enclosure 120, and a second mirror coil 160b located proximate to second end 330 of enclosure 120. Mirror coils 160 may be either internal or external to enclosure 120, may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. In some embodiments, coils 130, 140, 150, and 160 are designed or chosen according to certain constraints. For example, coils 130, 140, 150, and 160 may be designed according to constraints including: high required currents (maximum in some embodiments of approx. 10 MegaAmp-turns); steady-state continuous operation; vacuum design (protected from plasma impingement), toroidal shape, limit outgassing; materials compatible with 150C bakeout; thermal build-up; and cooling between shots. Fusion reactor 110 may include one or more heat injectors 170. Heat injectors 170 are generally operable to allow any appropriate heat to be added to fusion reactor 110 in order to heat plasma 310. In some embodiments, for example, heat injectors 170 may be utilized to add neutral beams in order to heat plasma 310 within fusion reactor 110. In operation, fusion reactor 110 generates fusion power by controlling the shape of plasma 310 for a nuclear fusion process using at least internal coils 140, encapsulating coils 150, and mirror coils 160. Internal coils 140 and encapsulating coils 150 are energized to form magnetic fields which confine plasma 310 into a shape such as the shape shown in FIGS. 3B and 5. Gases such as deuterium and tritium may then be reacted to make energetic particles which heat plasma 310 and the walls of enclosure 120. The generated heat may then be used for power. For example, a liquid metal coolant may carry heat from the walls of the reactor out to engines of an aircraft. In some embodiments, electrical power may also be extracted from fusion reactor 110 via MHD. In order to expand the volume of plasma 310 and create a more favorable minimum-β geometry, the number of internal coils can be increased to make a cusp. In some embodiments of fusion reactor 110, the sum of internal coils 140, center coil 130, and mirror coils 160 is an odd number in order to obtain the encapsulation by the outer ‘solenoid’ field (i.e., the magnetic field provided by encapsulating coils 150). This avoids making a ring cusp field and therefor ruining the encapsulating separatrix. Two internal coils 140 and center coil 130 with alternating polarizations give a magnetic well with minimum-β characteristics within the cusp and a quasi-spherical core plasma volume. The addition of two axial ‘mirror’ coils (i.e., mirror coils 160) serves to decrease the axial cusp losses and more importantly makes the recirculating field lines satisfy average minimum-β, a condition not satisfied by other existing recirculating schemes. In some embodiments, additional pairs of internal coils 140 could be added to create more plasma volume in the well. However, such additions may increase the cost and complexity of fusion reactor 110 and may require additional supports for coils internal to plasma 310. In the illustrated embodiments of fusion reactor 110, only internal coils 140 are within plasma 310. In some embodiments, internal coils 140 are suspending within enclosure 120 by one or more supports, such as support 750 illustrated in FIG. 7. While the supports sit outside the central core plasma well, they may still experience high plasma fluxes. Alternatively, internal coils 140 of some embodiments may be amenable to levitation, which would remove the risk and complexity of having support structures within plasma 310. FIG. 4 illustrates a simplified view of the coils of fusion reactor 110 and example systems for energizing the coils. In this embodiment, the field geometry is sized to be the minimum size necessary to achieve adequate ion magnetization with fields that can be produced by simple magnet technology. Adequate ion magnetization was considered to be ˜5 ion gyro radii at design average ion energy with respect to the width of the recirculation zone. At the design energy of 100 eV plasma temperature there are 13 ion diffusion jumps and at full 20 KeV plasma energy there are 6.5 ion jumps. This is the lowest to maintain a reasonable magnetic field of 2.2 T in the cusps and keep a modest device size. As illustrated in FIG. 4, certain embodiments of fusion reactor 110 include two mirror coils 160: a first mirror coil 160a located proximate to first end 320 of the enclosure and a second magnetic coil 160b located proximate to second end 330 of enclosure 120. Certain embodiments of fusion reactor 110 also include a center coil 130 that is located proximate to midpoint 340 of enclosure 120. Certain embodiments of fusion reactor 110 also include two internal coils 140: a first internal coil 140a located between center coil 130 and first end 320 of enclosure 120, and a second internal coil 140b located between center coil 130 and second end 330 of enclosure 120. In addition, certain embodiments of fusion reactor 110 may include two or more encapsulating coils 150. For example, fusion reactor 110 may include a first set of two encapsulating coils 150 located between first internal coil 140a and first end 320 of enclosure 120, and a second set of two encapsulating coils 150 located between second internal coil 140b and second end 330 of enclosure 120. In some embodiments, fusion reactor 110 may include any even number of encapsulating coils 150. In some embodiments, encapsulating coils 150 may be located at any appropriate position along center line 115 other than what is illustrated in FIG. 4. In general, encapsulating coils 150, as well as internal coils 140 and mirror coils 160, may be located at any appropriate position along center line 115 in order to maintain magnetic fields in the correct shape to achieve the desired shape of plasma 310. In some embodiments, electrical currents are supplied to coils 130, 140, 150, and 160 as illustrated in FIG. 4. In this figure, each coil has been split along center line 115 and is represented by a rectangle with either an “X” or an “O” at each end. An “X” represents electrical current that is flowing into the plane of the paper, and an “O” represents electrical current that is flowing out the plane of the paper. Using this nomenclature, FIG. 4 illustrates how in this embodiment of fusion reactor 110, electrical currents flow in the same direction through encapsulating coils 150, center coil 130, and mirror coils 160 (i.e., into the plane of the paper at the top of the coils), but flow in the opposite direction through internal coils 140 (i.e., into the plane of the paper at the bottom of the coils). In some embodiments, the field geometry of fusion reactor 110 may be sensitive to the relative currents in the coils, but the problem can be adequately decoupled to allow for control. First, the currents to opposing pairs of coils can be driven in series to guarantee that no asymmetries exist in the axial direction. The field in some embodiments is most sensitive to the center three coils (e.g., internal coils 140 and center coil 130). With the currents of internal coil 140 fixed, the current in center coil 130 can be adjusted to tweak the shape of the central magnetic well. This region can be altered into an axial-oriented ‘bar-bell’ shape by increasing the current on center coil 130 as the increase in flux ‘squeezes’ the sphere into the axial shape. Alternatively, the current on center coil 130 can be reduced, resulting in a ring-shaped magnetic well at midpoint 340. The radius of center coil 130 also sets how close the ring cusp null-line comes to internal coils 140 and may be chosen in order to have this null line close to the middle of the gap between center coil 130 and internal coils 140 to improve confinement. The radius of internal coils 140 serves to set the balance of the relative field strength between the point cusps and the ring cusps for the central well. The baseline sizes may be chosen such that these field values are roughly equal. While it would be favorable to reduce the ring cusp losses by increasing the relative flux in this area, a balanced approach may be more desirable. In some embodiments, the magnetic field is not as sensitive to mirror coils 160 and encapsulating coils 150, but their dimensions should be chosen to achieve the desired shape of plasma 310. In some embodiments, mirror coils 160 may be chosen to be as strong as possible without requiring more complex magnets, and the radius of mirror coils 160 may be chosen to maintain good diagnostic access to the device center. Some embodiments may benefit from shrinking mirror coils 160, thereby achieving higher mirror ratios for less current but at the price of reduced axial diagnostic access. In general, encapsulating coils 150 have weaker magnetic fields than the other coils within fusion reactor 110. Thus, the positioning of encapsulating coils 150 is less critical than the other coils. In some embodiments, the positions of encapsulating coils 150 are defined such that un-interrupted access to the device core is maintained for diagnostics. In some embodiments, an even number of encapsulating coils 150 may be chosen to accommodate supports for internal coils 140. The diameters of encapsulating coils 150 are generally greater than those of internal coils 140, and may be all equal for ease of manufacture and common mounting on or in a cylindrical enclosure 120. In some embodiments, encapsulating coils 150 may be moved inward to the plasma boundary, but this may impact manufacturability and heat transfer characteristics of fusion reactor 110. In some embodiments, fusion reactor 110 includes various systems for energizing center coil 130, internal coils 140, encapsulating coils 150, and mirror coils 160. For example, a center coil system 410, an encapsulating coil system 420, a mirror coil system 430, and an internal coil system 440 may be utilized in some embodiments. Coil systems 410-440 and coils 130-160 may be coupled as illustrated in FIG. 4. Coil systems 410-440 may be any appropriate systems for driving any appropriate amount of electrical currents through coils 130-160. Center coil system 410 may be utilized to drive center coil 130, encapsulating coil system 420 may be utilized to drive encapsulating coils 150, mirror coil system 430 may be utilized to drive mirror coils 160, and internal coil system 440 may be utilized to drive internal coils 140. In other embodiments, more or fewer coil systems may be utilized than those illustrated in FIG. 4. In general, coil systems 410-440 may include any appropriate power sources such as battery banks. FIG. 5 illustrates plasma 310 within enclosure 120 that is shaped and confined by center coil 130, internal coils 140, encapsulating coils 150, and mirror coils 160. As illustrated, an external mirror field is provided by mirror coils 160. The ring cusp flow is contained inside the mirror. A trapped magnetized sheath 510 that is provided by encapsulating coils 150 prevents detachment of plasma 310. Trapped magnetized sheath 510 is a magnetic wall that causes plasma 310 to recirculate and prevents plasma 310 from expanding outward. The recirculating flow is thus forced to stay in a stronger magnetic field. This provides complete stability in a compact and efficient cylindrical geometry. Furthermore, the only losses from plasma exiting fusion reactor 110 are at two small point cusps at the ends of fusion reactor 110 along center line 115. This is an improvement over typical designs in which plasma detaches and exits at other locations. The losses of certain embodiments of fusion reactor 110 are also illustrated in FIG. 5. As mentioned above, the only losses from plasma exiting fusion reactor 110 are at two small point cusps at the ends of fusion reactor 110 along center line 115. Other losses may include diffusion losses due to internal coils 140 and axial cusp losses. In addition, in embodiments in which internal coils 140 are suspended within enclosure 120 with one or more supports (e.g., “stalks”), fusion reactor 110 may include ring cusp losses due to the supports. In some embodiments, internal coils 140 may be designed in such a way as to reduce diffusion losses. For example, certain embodiments of fusion reactor 110 may include internal coils 140 that are configured to conform to the shape of the magnetic field. This may allow plasma 310, which follows the magnetic field lines, to avoid touching internal coils 140, thereby reducing or eliminating losses. An example embodiment of internal coils 140 illustrating a conformal shape is discussed below in reference to FIG. 7. FIG. 6 illustrates a magnetic field of certain embodiments of fusion reactor 110. In general, fusion reactor 110 is designed to have a central magnetic well that is desired for high beta operation and to achieve higher plasma densities. As illustrated in FIG. 6, the magnetic field may include three magnetic wells. The central magnetic well can expand with high Beta, and fusion occurs in all three magnetic wells. Another desired feature is the suppression of ring cusp losses. As illustrated in FIG. 6, the ring cusps connect to each other and recirculate. In addition, good MHD stability is desired in all regions. As illustrated in FIG. 6, only two field penetrations are needed and MHD interchange is satisfied everywhere. In some embodiments, the magnetic fields can be altered without any relocation of the coils by reducing the currents, creating for example weaker cusps and changing the balance between the ring and point cusps. The polarity of the currents could also be reversed to make a mirror-type field and even an encapsulated mirror. In addition, the physical locations of the coils could be altered. FIG. 7 illustrates an example embodiment of an internal coil 140 of fusion reactor 110. In this embodiment, internal coil 140 includes coil windings 710, inner shield 720, layer 730, and outer shield 740. In some embodiments, internal coil 140 may be suspending within enclosure 120 with one or more supports 750. Coil windings 710 may have a width 715 and may be covered in whole or in part by inner shield 720. Inner shield 720 may have a thickness 725 and may be covered in whole or in part by layer 730. Layer 730 may have a thickness 735 and may be covered in whole or in part by outer shield 740. Outer shield may have a thickness 745 and may have a shape that is conformal to the magnetic field within enclosure 120. In some embodiments, internal coil 140 may have an overall diameter of approximately 1.04 m. Coil windings 710 form a superconducting coil and carry an electric current that is typically in an opposite direction from encapsulating coils 150, center coil 130, and mirror coils 160. In some embodiments, width 715 of coils winding is approximately 20 cm. Coil windings 710 may be surrounded by inner shield 720. Inner shield 720 provides structural support, reduces residual neutron flux, and shields against gamma rays due to impurities. Inner shield 720 may be made of Tungsten or any other material that is capable of stopping neutrons and gamma rays. In some embodiments, thickness 725 of inner shield 720 is approximately 11.5 cm. In some embodiments, inner shield 720 is surrounded by layer 730. Layer 730 may be made of lithium (e.g., lithium-6) and may have thickness 735 of approximately 5 mm. Layer 730 may be surrounded by outer shield 740. Outer shield 740 may be made of FLiBe and may have thickness 745 of approximately 30 cm. In some embodiments, outer shield may be conformal to magnetic fields within enclosure 120 in order to reduce losses. For example, outer shield 740 may form a toroid. FIG. 8 illustrates a cut-away view of enclosure 120 of certain embodiments of fusion reactor 110. In some embodiments, enclosure 120 includes one or more inner blanket portions 810, an outer blanket 820, and one or more layers 730 described above. In the illustrated embodiment, enclosure 120 includes three inner blanket portions 810 that are separated by three layers 730. Other embodiments may have any number or configuration of inner blanket portions 810, layers 730, and outer blanket 820. In some embodiments, enclosure 120 may have a total thickness 125 of approximately 80 cm in many locations. In other embodiments, enclosure 120 may have a total thickness 125 of approximately 1.50 m in many locations. However, thickness 125 may vary over the length of enclosure 120 depending on the shape of the magnetic field within enclosure 120 (i.e., the internal shape of enclosure 120 may conform to the magnetic field as illustrated in FIG. 3b and thus many not be a uniform thickness 125). In some embodiments, inner blanket portions 810 have a combined thickness 815 of approximately 70 cm. In other embodiments, inner blanket portions 810 have a combined thickness 815 of approximately 126 cm. In some embodiments, inner blanket portions are made of materials such as Be, FLiBe, and the like. Outer blanket 820 is any low activation material that does not tend to become radioactive under irradiation. For example, outer blanket 820 may be iron or steel. In some embodiments, outer blanket 820 may have a thickness 825 of approximately 10 cm. FIGS. 9A and 9B illustrate various examples of one or more support stalks 910 supporting an internal coils 140 within fusion reactor 110, in accordance with certain embodiments. Plasma can be confined with electromagnetic fields and if heated can be made to produce net energy via nuclear fusion reactions. These fields can be created by electrodes and/or magnetic field coils. Often these are external to the plasma confinement chamber, but some configurations require vacuum compatible, internal components. These internal electrodes and/or magnetic field coils may require mechanical support and protection from the hazardous nature of the plasma environment, without severely disrupting the plasma. Prior internal-to-plasma components have been supported via cables, insulated feedthroughs, or levitated by external magnetic fields. Each of these approaches pose problems. Cables may provide structural support, but provide no isolation from the plasma. Cables may also be disruptive to the plasma environment as flow around the cables may not be smooth, and cable surfaces are often rough. Insulated feedthroughs usually only provide one service, such as power, cooling, or diagnostics, and may be made of ceramic materials. Ceramic materials are brittle, and may provide little support. Also, a ceramic surface may suffer from electrical charging as the plasma deposits charge on the surface that can disrupt the plasma environment. External levitation is an overly complex approach and cannot be sustained indefinitely. External levitation is therefore an inadequate solution for maintaining steady-state operation, which may be desirable for operating a fusion reactor. Some embodiments of the present disclosure may address these and other deficiencies of existing approaches by using one or more support stalks to provide mechanical support, service of electrical, diagnostics, and cooling lines, and protection from the plasma environment in a manner designed to minimize deleterious effects on plasma confinement. In general, support stalks 910 may provide mechanical support for internal coils 140 of fusion reactor 110. Internal coils 140 may require special support mechanisms at least in part because they may be immersed in plasma. In some embodiments, one or more support stalks may mechanically support internal coils 140 and be able to withstand sustained contact with the plasma environment without disrupting it. In some embodiments, support stalks may include an internal cavity through which any suitable components may extend into the interior of internal coil 140. FIG. 9A illustrates a single support stalk 910 supporting internal coil 140 within fusion reactor 110, in accordance with certain embodiments. Although FIG. 9A illustrates a single support stalk 910, the present disclosure contemplates that any suitable number of support stalks 910 may be used support internal coil 140. For example, in some embodiments each internal coil 140 may be supported by two or three support stalks 910. The present disclosure contemplates that the one or more support stalks 910 may have any suitable shape. For example, and as illustrated in FIG. 9A, support stalk 910 may have an ellipsoid cross-section. In some embodiments, support stalk 910 may be coupled to internal coil 140 at a first end 920 of support stalk 910 and coupled to enclosure 120 at a second end 930 of support stalk 910. The present disclosure contemplates that support stalk 910 may be coupled to internal coil 140 and enclosure 120 in any suitable manner. As an example, support stalk 910 may be welded to internal coil 140 and enclosure 120. As another example, support stalk 910 may be coupled to internal coil 140 and enclosure 120 using any suitable number of any suitable fasteners. The present disclosure contemplates the use of any suitable combination of materials for coupling support stalk 910 to internal coil 140 and enclosure 120. In some embodiments, the one or more support stalks 910 may be modular, which may advantageously allow for easier replacement and/or servicing of support stalks 910. FIG. 9B illustrates another example of support stalks 910 supporting internal coil 140 within enclosure 120. As described above, the present disclosure contemplates that fusion reactor 110 may have any suitable number of support stalks 910 supporting internal coil 140. FIG. 9B illustrates an embodiment in which internal coil 140 is supported by four support stalks 910. As described above, support stalks 910 may have any suitable shape. In some embodiments, and as illustrated in FIG. 9B, support stalks 910 may be substantially rod-shaped. FIG. 10 illustrates another view of support stalk 910 coupled to internal coil 140, in accordance with certain embodiments. In some embodiments, support stalk 910 may include an internal cavity 1010. In some embodiments, support stalk 910 may provide mechanical support for suspending internal coil 140 in plasma 310. In some embodiments, support stalk 910 can be placed in tension or compression. Support stalk 910 may be formed from any suitable material or combination of materials. As an example, support stalk 910 may be formed from stainless steel or tungsten. As another example, support stalk 910 may be formed from aluminum coated with tungsten. The one or more materials used for forming support stalk 910 may vary according to particular applications of support stalk 910 within fusion reactor 110. As an example, in some embodiments internal coil 140 may weigh substantially more than in other embodiments, possibly necessitating use of a material better suited for supporting a heavier internal coil 140. Support stalk 910 may be located in any suitable area of enclosure 120. In some embodiments, support stalk 910 may be immersed in plasma 310. In some embodiments, support stalk 910 may be located in fusion reactor 110 in an area where plasma 310 concentration is weakest, such as in a recirculation zone. Support stalk 910 may be adapted to withstand exposure to plasma 310 within enclosure 120 without having a deleterious effect on confinement of plasma 310. As described above, support stalk 910 may have any suitable shape. In some embodiments, support stalk 910 may have a cross-sectional shape of an ellipsoid. In some embodiments, the ellipsoid shape may allow plasma to flow smoothly around support stalk 910, which may advantageously prevent deleterious effects on plasma confinement by support stalk 910. In some embodiments, the cross-section of support stalk 910 is thinner along an axis 1020 orthogonal to the magnetic field, as illustrated by arrows 1030. This orientation is further described below in FIGS. 11A and 11B. Orienting support stalk 910 in such a manner may advantageously result in reduced plasma flux to the surface, while still providing stiffness in the direction of the magnetic field lines 1030. In some embodiments, the surface of support stalk 910 may be coated to provide sputtering resistance to impacting plasma. In some embodiments, support stalk 910 may include an internal cavity 1010. Internal cavity 1010 may house any suitable components. For example, internal cavity 1010 may contain power, cooling, and diagnostic lines that extend to the interior of internal coil 140. In some embodiments, internal cavity 1010 may contain current carrying wires to produce magnetic fields to further shield support stalk 910 from impacting plasma 310. FIGS. 11A and 11B illustrate various examples of cross-sections of support stalk 910, in accordance with certain embodiments. As described above, support stalk 910 may have an ellipsoid shaped cross-section that is thinner along an axis 1020 orthogonal to the magnetic field 1030. In some embodiments, support stalk 910 may have an internal cavity 1010. Internal cavity 1010 may contain any suitable components. For example, internal cavity 1010 may contain current carrying wires 1110 for producing magnetic fields to shield support stalk 910 from impacting plasma 310. In some embodiments, internal cavity 1010 may also contain power lines 1120, diagnostic lines 1130, and cooling lines 1140, or other suitable components. By running power lines 1120, diagnostic lines 1130, and cooling lines 1140 through internal cavity 1010 of support stalk 910, these components may be coupled to structures immersed in plasma 310, such as internal coil 140, while at the same time isolating the power lines 1120, diagnostic lines 1130, and cooling lines 1140 from plasma 310. FIG. 11A illustrates an example arrangement of current carrying wires 1110 in internal cavity 1010 of support stalk 910. In some embodiments, and as illustrated in FIG. 3A, current carrying wires 1110 may be arranged in internal cavity 1010 to produce an encapsulating magnetic field 1150 to shield support stalk 910 from impacting plasma 310. In such an embodiment, one or more current carrying wires 1110 may carry current in a first direction 1160 on a first side 1170 of internal cavity 1010, while one or more current carrying wires 1110 may carry current in a second direction 1180 opposite the first direction 1160 on a second side 1190 of internal cavity 1010. In some embodiments, the encapsulating magnetic field 1150 may advantageously shield support stalk 910 from impacting plasma 310. FIG. 11B illustrates another example arrangement of current carrying wires 1110 in internal cavity 1010 of support stalk 910. In some embodiments, and as illustrated in FIG. 11B, current carrying wires 1110 may be arranged in internal cavity 1010 to produce a high local surface field (i.e., alternating current fence) around support stalk 910. In such an embodiment, the direction of current in current carrying wires 1110 is alternated between neighboring sections of wire 1110, such that wires 1110 carrying current in a first direction 1160 are positioned next to wires 1110 carrying current in a second direction 1180. In some embodiments, multiple current carrying wires 1110 may be used to create such a configuration. In some embodiments, a single current carrying wire 1110 may be laid out such that the desired orientation of current is achieved. A similar configuration may be created on the second side 1190 of internal cavity 1010 in support stalk 910. In some embodiments, the high local surface field may deflect plasma and may advantageously shield support stalk 910 from impacting plasma 310. In some embodiments, the alternating current fence configuration may advantageously produce smaller, more localized fields close to the surface of support stalk 910, preventing disruption of other magnetic fields in fusion reactor 110. FIGS. 12A and 12B illustrate additional views of current carrying wires 1110 within support stalk 910 illustrated in FIGS. 11A and 11B. FIG. 12A illustrates an arrangement of current carrying wires in accordance with the embodiment described above with respect to FIG. 11A. As described above, current carrying wires can be arranged to form an encapsulating magnetic field around support stalk 910. In such a configuration, current carrying wires 1110 may be arranged such that one or more current carrying wires 1110 on first side 1170 of internal cavity 1010 may carry current in a first direction 1160, while one or more current carrying wires 1110 on a second side 1190 of internal cavity 1010 may carry current in a second direction 1180 opposite the first direction 1160. FIG. 12B illustrates an arrangement of current carrying wires 1110 in accordance with the embodiment described above with respect to FIG. 11B. As described above, in the alternating current fence embodiment, magnetic fields for deflecting plasma 310 are created by alternating the direction of current in current carrying wires 1110, such that wire 1110 carrying current in a first direction 1160 is positioned adjacent wire 1110 carrying current in a second direction 1180. FIG. 13 illustrates an example computer system 1300. In particular embodiments, one or more computer systems 1300 are utilized by fusion reactor 110 for any aspects requiring computerized control. Particular embodiments include one or more portions of one or more computer systems 1300. Herein, reference to a computer system may encompass a computing device, and vice versa, where appropriate. Moreover, reference to a computer system may encompass one or more computer systems, where appropriate. This disclosure contemplates any suitable number of computer systems 1300. This disclosure contemplates computer system 1300 taking any suitable physical form. As example and not by way of limitation, computer system 1300 may be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC) (such as, for example, a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, a tablet computer system, or a combination of two or more of these. Where appropriate, computer system 1300 may include one or more computer systems 1300; be unitary or distributed; span multiple locations; span multiple machines; span multiple data centers; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems 1300 may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computer systems 1300 may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computer systems 1300 may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate. In particular embodiments, computer system 1300 includes a processor 1302, memory 1304, storage 1306, an input/output (I/O) interface 1308, a communication interface 1310, and a bus 1312. Although this disclosure describes and illustrates a particular computer system having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable computer system having any suitable number of any suitable components in any suitable arrangement. In particular embodiments, processor 1302 includes hardware for executing instructions, such as those making up a computer program. As an example and not by way of limitation, to execute instructions, processor 1302 may retrieve (or fetch) the instructions from an internal register, an internal cache, memory 1304, or storage 1306; decode and execute them; and then write one or more results to an internal register, an internal cache, memory 1304, or storage 1306. In particular embodiments, processor 1302 may include one or more internal caches for data, instructions, or addresses. This disclosure contemplates processor 1302 including any suitable number of any suitable internal caches, where appropriate. As an example and not by way of limitation, processor 1302 may include one or more instruction caches, one or more data caches, and one or more translation lookaside buffers (TLBs). Instructions in the instruction caches may be copies of instructions in memory 1304 or storage 1306, and the instruction caches may speed up retrieval of those instructions by processor 1302. Data in the data caches may be copies of data in memory 1304 or storage 1306 for instructions executing at processor 1302 to operate on; the results of previous instructions executed at processor 1302 for access by subsequent instructions executing at processor 1302 or for writing to memory 1304 or storage 1306; or other suitable data. The data caches may speed up read or write operations by processor 1302. The TLBs may speed up virtual-address translation for processor 1302. In particular embodiments, processor 1302 may include one or more internal registers for data, instructions, or addresses. This disclosure contemplates processor 1302 including any suitable number of any suitable internal registers, where appropriate. Where appropriate, processor 1302 may include one or more arithmetic logic units (ALUs); be a multi-core processor; or include one or more processors 1302. Although this disclosure describes and illustrates a particular processor, this disclosure contemplates any suitable processor. In particular embodiments, memory 1304 includes main memory for storing instructions for processor 1302 to execute or data for processor 1302 to operate on. As an example and not by way of limitation, computer system 1300 may load instructions from storage 1306 or another source (such as, for example, another computer system 1300) to memory 1304. Processor 1302 may then load the instructions from memory 1304 to an internal register or internal cache. To execute the instructions, processor 1302 may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor 1302 may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor 1302 may then write one or more of those results to memory 1304. In particular embodiments, processor 1302 executes only instructions in one or more internal registers or internal caches or in memory 1304 (as opposed to storage 1306 or elsewhere) and operates only on data in one or more internal registers or internal caches or in memory 1304 (as opposed to storage 1306 or elsewhere). One or more memory buses (which may each include an address bus and a data bus) may couple processor 1302 to memory 1304. Bus 1312 may include one or more memory buses, as described below. In particular embodiments, one or more memory management units (MMUs) reside between processor 1302 and memory 1304 and facilitate accesses to memory 1304 requested by processor 1302. In particular embodiments, memory 1304 includes random access memory (RAM). This RAM may be volatile memory, where appropriate. Where appropriate, this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, where appropriate, this RAM may be single-ported or multi-ported RAM. This disclosure contemplates any suitable RAM. Memory 1304 may include one or more memories 1304, where appropriate. Although this disclosure describes and illustrates particular memory, this disclosure contemplates any suitable memory. In particular embodiments, storage 1306 includes mass storage for data or instructions. As an example and not by way of limitation, storage 1306 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, or a Universal Serial Bus (USB) drive or a combination of two or more of these. Storage 1306 may include removable or non-removable (or fixed) media, where appropriate. Storage 1306 may be internal or external to computer system 1300, where appropriate. In particular embodiments, storage 1306 is non-volatile, solid-state memory. In particular embodiments, storage 1306 includes read-only memory (ROM). Where appropriate, this ROM may be mask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), electrically alterable ROM (EAROM), or flash memory or a combination of two or more of these. This disclosure contemplates mass storage 1306 taking any suitable physical form. Storage 1306 may include one or more storage control units facilitating communication between processor 1302 and storage 1306, where appropriate. Where appropriate, storage 1306 may include one or more storages 1306. Although this disclosure describes and illustrates particular storage, this disclosure contemplates any suitable storage. In particular embodiments, I/O interface 1308 includes hardware, software, or both, providing one or more interfaces for communication between computer system 1300 and one or more I/O devices. Computer system 1300 may include one or more of these I/O devices, where appropriate. One or more of these I/O devices may enable communication between a person and computer system 1300. As an example and not by way of limitation, an I/O device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touch screen, trackball, video camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. This disclosure contemplates any suitable I/O devices and any suitable I/O interfaces 1308 for them. Where appropriate, I/O interface 1308 may include one or more device or software drivers enabling processor 1302 to drive one or more of these I/O devices. I/O interface 1308 may include one or more I/O interfaces 1308, where appropriate. Although this disclosure describes and illustrates a particular I/O interface, this disclosure contemplates any suitable I/O interface. In particular embodiments, communication interface 1310 includes hardware, software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between computer system 1300 and one or more other computer systems 1300 or one or more networks. As an example and not by way of limitation, communication interface 1310 may include a network interface controller (NIC) or network adapter for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network, such as a WI-FI network. This disclosure contemplates any suitable network and any suitable communication interface 1310 for it. As an example and not by way of limitation, computer system 1300 may communicate with an ad hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, computer system 1300 may communicate with a wireless PAN (WPAN) (such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAX network, a cellular telephone network (such as, for example, a Global System for Mobile Communications (GSM) network), or other suitable wireless network or a combination of two or more of these. Computer system 1300 may include any suitable communication interface 1310 for any of these networks, where appropriate. Communication interface 1310 may include one or more communication interfaces 1310, where appropriate. Although this disclosure describes and illustrates a particular communication interface, this disclosure contemplates any suitable communication interface. In particular embodiments, bus 1312 includes hardware, software, or both coupling components of computer system 1300 to each other. As an example and not by way of limitation, bus 1312 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCIe) bus, a serial advanced technology attachment (SATA) bus, a Video Electronics Standards Association local (VLB) bus, or another suitable bus or a combination of two or more of these. Bus 1312 may include one or more buses 1312, where appropriate. Although this disclosure describes and illustrates a particular bus, this disclosure contemplates any suitable bus or interconnect. Herein, a computer-readable non-transitory storage medium or media may include one or more semiconductor-based or other integrated circuits (ICs) (such, as for example, field-programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disk drives (HDDs), hybrid hard drives (HHDs), optical discs, optical disc drives (ODDs), magneto-optical discs, magneto-optical drives, floppy diskettes, floppy disk drives (FDDs), magnetic tapes, solid-state drives (SSDs), RAM-drives, SECURE DIGITAL cards or drives, any other suitable computer-readable non-transitory storage media, or any suitable combination of two or more of these, where appropriate. A computer-readable non-transitory storage medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context. The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Although the present invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims.
045270651	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The container for storing radioactive material includes a cylindrical vessel 1 which is open at one end. In this way, the upper end portion of the vessel defines the receiving opening 2 for loading the vessel with fuel elements (not shown). The cover and vessel are made of a mechanically strong material. The vessel 1 includes a vessel-shaped base body 4 made of a material such as cast iron or cast steel. The cover has a main body also made of cast iron or cast steel and is provided with a protective layer 16 of corrosion-resistant material such as ceramic. The upper end portion of the vessel 1 and the peripheral portion of the cover 6 define respective joint surfaces 10 and 8. These joint surfaces are mutually adjacent and define the partition interface between the vessel 1 and cover 6 when the cover is seated on the vessel. A weld plating 3 is applied to joint surface 10 of the upper end portion of the vessel 1 and to a portion of the outside surface of the vessel as shown. The weld plating 3 is annular and is made of cold-weldable, corrosive resistant material. A material of the kind from which the annular weld plating is made is an alloy NiMo16Cr16Ti having the tradename Hastelloy C-4. The vessel 1 is closed by the sealing cover 6 welded thereto. This cover 6 has a peripheral portion which includes an annular upwardly extending projection 7 formed at the outer surface thereof. At the region of the peripheral portion facing the vessel 1, the cover 6 is beveled to define the circular annular surface 8. The peripheral portion of the cover 6 is enclosed about its entire periphery with a weld plating 9 likewise made of a cold-weldable material. The weld plating is in the form of an annular band extending laterally from the projection 7 to the inner edge of the annular surface 8. The weld platings 3 and 9 are applied to the vessel 1 and to the cover 6, respectively, by surface-layer welding and are built up by depositing layer upon layer of the cold weldable material Hastelloy C-4. A weld 13 of cold-weldable material seals the cover 6 to the vessel 1 after the vessel has been filled with radioactive material. For further details directed to the partition interface and the joining of the cover 6 to the vessel 1, reference may be had to the copending patent application of Franz-Wolfgang Popp entitled "A Container for the Long-Term Storage of Radioactive Materials" filed on Dec. 14, 1982 and having Ser. No. 449,567. Ribs 15 of a corrosion-resistant material are applied to the vessel-shaped base body 4 of the vessel 1 on the external surface 5 thereof by the surface-layer welding process. The ribs extend parallel to the longitudinal axis of the base body and about the periphery thereof as shown. NiMo16Cr16Ti known commercially as Hastelloy C-4 was selected as the material for the ribs. The plurality of ribs 15 partition the outside surface 5 of the base body 4 into segment-like areas 11. In these areas, the base body 4 is coated with a corrosion-resistant protective layer 12 of ceramic material which is applied by spraying the material into each segment area formed by the plurality of ribs 15. The point of attachment of the ribs 15 is covered by the ceramic material applied to the base body 4. The ribs 15 project somewhat beyond the surface of the ceramic protective layer 12. By virtue of this arrangement, the metallic ribs 15 provide mechanical protection for the ceramic protective layer areas. FIG. 2 shows a portion of the lower part of the vessel 1 of a container of the type illustrated in FIG. 1. Here, the lower peripheral edge of the vessel is provided with a rib plating 14 to enable the container to withstand a higher mechanical loading. This arrangement protects the protective layer 12 from rupturing and breaking away from the base body at the peripheral edge. Other modifications and variations to the embodiments described will not be apparent to those skilled in the art. Accordingly, the aforesaid embodiments are not to be construed as limiting the breadth of the invention. The full scope and extent of the present contribution can only be appreciated in view of the appended claims.
	claims	1. A replacement light apparatus for a radiation generating device, comprising:a base plate;a grip plate extending from a first surface of the base plate;a bearing member extending from a second surface of the base plate that is opposite the first surface, the bearing member including a bearing surface disposed in a first plane that is perpendicular to a second plane, in which the base plate is disposed; anda light source mounted on the bearing surface of the bearing member and adapted to project a cone of light centered on an illumination axis that extends perpendicular to the bearing surface. 2. The apparatus of claim 1, wherein the light source is mounted flush on the bearing surface. 3. The apparatus of claim 1, wherein the light source comprises a light-emitting-diode centered on the illumination axis. 4. The apparatus of claim 1, wherein the bearing member comprises a bearing plate and a body portion disposed between the base plate and the bearing plate, the bearing plate defining the bearing surface and the body portion including a through-bore for accommodating an electrical connection for the light source. 5. The apparatus of claim 1, further comprising a circuit connected to the light source for driving the light source, the circuit including a pair of drivers connected in parallel. 6. The apparatus of claim 5, wherein each of the pair of drivers includes a 500 mA AC/DC driver. 7. A replacement light apparatus for a radiation generating device, comprising:a base plate;a grip plate extending from a first surface of the base plate;a bearing member extending from a second surface of the base plate that is opposite the first surface, the bearing member including a bearing surface disposed in a first plane that is perpendicular to a second plane, in which the base plate is disposed; anda light-emitting-diode mounted on the bearing surface of the bearing member and adapted to project a cone of light centered on an illumination axis that extends perpendicular to the bearing surfacea power sourced connected to the light-emitting-diode; anda pair of light-emitting-diode drivers connected in parallel between the light-emitting-diode and the power source. 8. The apparatus of claim 7, wherein each of the pair of light-emitting-diode drivers includes a 500 mA AC/DC driver. 9. The apparatus of claim 7, wherein the light-emitting-diode is mounted flush on the bearing surface. 10. The apparatus of claim 7, wherein the light-emitting is centered on the illumination axis. 11. The apparatus of claim 7, wherein the bearing member comprises a bearing plate and a body portion disposed between the base plate and the bearing plate, the bearing plate defining the bearing surface and the body portion including a through-bore for accommodating an electrical connection with the power source and light-emitting-diode drivers. 12. A radiation generating device, comprising:a linear particle accelerator;a collimator arranged in proximity to the linear particle accelerator for aligning the particles departing the accelerator and projecting a radiation field; anda light projector comprising:a housing,an optical assembly carried by the housing and having an optical axis, anda light fixture removably disposed in the housing, the light fixture including a bearing plate defining a bearing surface disposed in a first plane that is perpendicular to the optical axis, and a light source mounted on the bearing surface and centered on the optical axis, the light source adapted to project a cone of light centered on an illumination axis that is coaxial with the optical axis. 13. The device of claim 12, wherein the light projector comprises a field lamp projector for providing an illuminated estimation of the radiation field projected from the collimator. 14. The device of claim 12, wherein the light projector comprises an optical distance indicator and the optical assembly includes a lens carrying a plurality of numbers for being projected on a radiation target for indicating a distance between the collimator and the target. 15. The device of claim 12, wherein the light source is mounted flush on the bearing surface. 16. The device of claim 12, wherein the light source comprises a light-emitting-diode centered on the illumination axis. 17. The device of claim 12, wherein the bearing member comprises a bearing plate and a body portion disposed between the base plate and the bearing plate, the bearing plate defining the bearing surface and the body portion including a through-bore for accommodating an electrical connection for the light source. 18. The device of claim 12, further comprising a circuit connected to the light source for driving the light source, the circuit including a power source and a pair of drivers connected in parallel between the power source and the light source. 19. The device of claim 18, wherein each of the pair of drivers includes a 500 mA AC/DC driver. 20. A method of upgrading a radiation generating device, the method comprising:removing a cover from a collimator of the radiation generating device; andreplacing an existing light fixture with an upgraded light fixture, including:disconnecting the existing light fixture from a power source,removing the existing light fixture from a light fixture housing by sliding the existing light fixture out along a linear axis of a socket of the housing, in which the existing light fixture resides,connecting the upgraded light fixture to the power source, andcentering a light source of the upgraded light fixture on an optical axis of an optical assembly carried by the housing by sliding the upgraded light fixture into the socket of the housing along the linear axis, the optical axis being perpendicular to the linear axis of the socket. 21. The method of claim 20, wherein the light source of the upgraded light fixture comprises a light-emitting-diode and wherein connecting the upgraded light fixture to the power source comprises connecting a pair of light-emitting-diode drivers in parallel between the power source and the light-emitting-diode. 22. A method of projecting a pattern of light on a target of a radiation generating device, the method comprising:emitting a cone of light to produce a pattern of light on the target, wherein the cone of light is emitted along an illumination axis with a light source, the light source being carried by and removably disposed in a projector housing of the radiation generating device and the illumination axis being disposed coaxially with an optical axis of an optical assembly carried by the projector housing. 23. The method of claim 22, wherein emitting the cone of light to produce a pattern of light comprises estimating a pattern of radiation on the target. 24. The method of claim 22, wherein emitting the cone of light comprises emitting the cone of light through a lens carrying a plurality of numbers such that the pattern of light comprises one or more numbers projected on the target, the one or more numbers indicating a distance between the radiation generating device and the target. 25. The method of claim 22, wherein emitting the cone of light comprises energizing a light-emitting-diode. 26. The method of claim 22, further comprising projecting a radiation field onto the target with the radiation generating device.
055662170	description	BEST MODE FOR CARRYING OUT THE INVENTION Referring now to FIG. 1, there is illustrated a nuclear fuel assembly, generally designated 10, including a plurality of fuel elements or rods 12 supported between an upper tie plate 14 and a lower tie plate 16. Fuel rods 12 pass through a plurality of fuel rod spacers 18 at vertically spaced positions along the fuel bundle. The spacers 18 provide intermediate support to retain the elongated fuel rods 12 in spaced relation relative to one another and to restrain the fuel rods from lateral vibration. With reference to FIGS. 1 and 2, a 10.times.10 array of fuel rods is disclosed. It will be appreciated, however, that the invention hereof is applicable to arrays of fuel rods of different numbers, for example, 8.times.8 arrays. Each fuel rod 18 is formed of an elongated tubular cladding material, with the nuclear fuel and other materials sealed in the tube by end plugs. The lower end plugs register in bores formed in the lower tie plate 16, while the upper end plugs are disposed in cavities in the upper tie plate 14. Additionally, the fuel rod assembly includes a channel 20 of substantially square cross-section sized to form a sliding fit over the upper and lower tie plates and the spacers so that the nuclear fuel bundle, including the channel, tie plates, rods and spacers can be removed. Turning now to FIG. 2, there is illustrated a spacer 18 constructed in accordance with the present invention and having a plurality of individual ferrules 22 and springs 24, each ferrule having an associated spring. The ferrules 22 are arranged in a square matrix in which each ferrule receives a fuel rod and maintains the fuel rod spaced and restrained relative to adjoining fuel rods. The spring assembly 24 is provided each ferrule for purposes of biasing the fuel rod in a lateral direction against stops 26 opposite the springs whereby the fuel rods are maintained in a predetermined position relative to one another and in the spacer 18. Each spacer 18 also includes a marginal band 28 with inwardly directed upper flow tabs 30. Referring now to FIGS. 4 and 5, each spacer ferrule 22 has a generally cylindrical configuration. The wall of each cylindrical ferrule is indented at circumferentially spaced locations along one side of the ferrule to form the inwardly directed stops 26. It will be appreciated that the stops 26 extend the full height of the ferrule, although the stops could be provided at axially spaced locations along the height of the ferrule. As best illustrated in FIGS. 10-12, each ferrule 22 includes a central opening 30 opposite the stops 26. Opening 30 is straddled by band portions 32 above and below the opening. As indicated previously, the ferrules are symmetrically disposed within the spacer 18 with the side portion 34 of each spacer engaging the band portions 32 of the next-adjacent spacer. Also, the opposite sides of the ferrules (the sides of the ferrule 90.degree. from side portion 34 and band portions 32) engage one another. Preferably, the ferrules are welded one to the other in the spacer 18 at their areas of engagement. Referring now to FIGS. 6-9, there is illustrated a spring 40 for use with each of the ferrules 22. Spring 40 includes a flat leaf spring body 41 having sides 42 defining and lying in a plane. Opposite spring end portions 44 extend across the spring coupling between the opposite sides 42 and projecting to one side of the plane at opposite ends of the spring 40. An outwardly projecting convex dimple 46 is provided in each of the end portions 44 for engagement with the fuel rod in the associated ferrule 22. Substantially medially of the length of the spring 40, there is provided an intermediate cross-piece or central portion 48 which projects to the opposite side of the plane containing the spring 40. The cross-piece 48 has a convexly-shaped dimple 50 projecting toward the plane. Adjacent opposite sides of the cross-piece 48, there is provided a pair of projections or protuberances 52 which project from the plane on the same side thereof as the end pieces 44. From a review of FIG. 8, it will be appreciated that the cross-piece 48 and the end pieces 44 are spaced from one another to define a pair of openings 54 on opposite sides of the cross-piece 48 and bounded by the cross-piece 48, end pieces 44 and sides 42. The cross-piece 48 has a height dimension enabling it to be received within the opening 30 of the ferrule. Additionally, the protuberances 52 lie along opposite sides of the spring a distance from one another such that they engage the outer surface of the ferrule 22 adjacent opposite side edges of opening 30, as illustrated in FIG. 4. It will also be appreciated that the openings 54 in the spring 40 are sized to receive the ferrule band portions 32 above and below the ferrule opening 30. In the spacer and as indicated previously, the ferrules 22 are welded one to the other to afford structural integrity within the spacer. The adjacent ferrules are secured one to the other with the springs in place. That is, the springs are located prior to assembly with the sides 42 straddling the opening 30 and the cross-piece 48 disposed within the opening 30. The sides 42 lie external to both ferrules, with the projections 52 engaging the outer surface of one ferrule adjacent opposite sides of opening 30. It will be appreciated that in this configuration, and as illustrated in FIG. 5, the end portions 44 lie above and below the upper and lower edges of the ferrules 22, respectively. Thus, the protuberances 46 engage the fuel rods above and below the ferrule and bias the fuel rods against the opposing stops 26. The cross-piece 48 of the spring bears against the portion 34 of the adjacent ferrule 22 between its stops 26 and thus provides a reaction force for the spring 40 bearing against the fuel rod of the one ferrule 22. Consequently, it will be seen that the individual ferrules are reduced in height minimizing the magnitude of the ferrule material, yet maintain their structural integrity surrounding and positioning the fuel rods. In a typical spacer, the ferrules have a height-to-diameter ratio within a range of 0.8 to 0.4 and preferably the height-to-diameter ratio is about 0.6. The height H and diameter D dimensions are illustrated in FIG. 11. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
	description	This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The U.S. Government has certain rights in this invention. The present invention is directed to a system and method for consolidating used nuclear fuel. Storage and disposal of spent or used nuclear fuel is an ongoing concern for nuclear utilities. Currently, nuclear utilities are placing used nuclear fuel rods in dry storage canisters for on-site storage. The canister designs have evolved over the years into a small, high-capacity storage canister that minimizes impact on power production, such as reduced loading, lifting, transport activities, while holding more used nuclear fuel rods. Containers are being designed to permit interim on-site storage, transportation, and ultimate disposal/long-term storage in a repository. However, it will be necessary to break down and consolidate nuclear fuel assemblies. That is, non-fuel bearing components (i.e. structural components) must be separated from used nuclear fuel rods to permit high-density packaging of the fuel rods in the containers. There is a need for a system and method for safely consolidating the used nuclear fuel rods in such containers at a sufficient output rate in order for such consolidating to be viable. The disclosure is directed to a system for supporting used nuclear fuel, includes a structure securable in a recess adjacent a fuel assembly containing used nuclear fuel rods, the fuel assembly having a top nozzle assembly. The system provides an elongated top nozzle assembly removal tool operably suspendable from a drive source for removing the top nozzle assembly from the fuel assembly, exposing ends of the used nuclear fuel rods facing the drive source. The system provides an elongated tube cutter tool having a plurality of cutters operably suspendable from the drive source for cutting and removing a predetermined segment of corresponding tubes in the fuel assembly. The system provides an elongated rod extraction gripping tool having a frame having a longitudinal axis and a gripper array assembly selectively movable along the axis relative to the frame for selectively engaging ends of a row of used nuclear fuel rods, the rod extraction gripping tool operably suspendable from the drive source for removing the row of used nuclear fuel rods from the fuel assembly. The system provides an accumulator for selectively laterally arranging the row of used nuclear fuel rods therein, and an elongated second rod gripping tool operably suspendable from the drive source for moving at least one used nuclear fuel rod of the selectively laterally arranged row of used nuclear fuel rods from the accumulator to a consolidation canister for receiving the at least one used nuclear fuel rod therein. The disclosure is also directed to a rod extraction gripping tool includes an elongated frame having a longitudinal axis and a gripper array assembly selectively movable along the axis relative to the frame for selectively engaging ends of a row of used nuclear fuel rods contained in a fuel assembly, the rod extraction gripping tool operably suspendable from a drive source for removing the row of used nuclear fuel rods from the fuel assembly. The rod extraction gripping tool provides the gripper array assembly tool having a plurality of grippers, each gripper independently having a predetermined float length along the axis capable of gripping an end of a corresponding used nuclear fuel rod of the row of used nuclear fuel rods, each of the used nuclear fuel rods capable of having a length differential relative to another used nuclear fuel rod, the length differential equal to or less than the predetermined float length. The disclosure is yet further directed to a method for consolidating used nuclear fuel, includes securing a structure in a recess for supporting a fuel assembly containing used nuclear fuel rods therein, the fuel assembly having a top nozzle assembly. The method further provides suspendably removing the top nozzle assembly from the fuel assembly with an elongated top nozzle assembly removal tool, exposing ends of the used nuclear fuel rods facing the drive source. The method further provides suspendably cutting and removing a predetermined segment of corresponding tubes in the fuel assembly with an elongated tube cutter tool having a plurality of cutter. The method further provides suspendably removing a row of used nuclear fuel rods from the fuel assembly with an elongated rod extraction gripping tool. The method further provides selectively laterally arranging the row of used nuclear fuel rods in an accumulator, and suspendably moving the selectively laterally arranged used nuclear fuel rods from the accumulator to a consolidation canister for receiving the selectively laterally arranged used nuclear fuel rods therein. Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts. The system of the present invention provides benefits, such as safely consolidating used nuclear fuel rods placed in a recess by maintaining a predetermined spacing from the top of the recess such as a liquid filled recess, such as a pool, for the fuel rods at all times during the consolidation process. In one embodiment, the consolidation process is an automated process, utilizing one or more driving sources, such as a robotic arm, permitting fast, efficient processing of the fuel rods. The system and method of the present invention permits the consolidation of multiple used nuclear fuel rods, such as a full row of an array of fuel rods, resulting in the ability to achieve an increased rate of fuel rod consolidation. The system of the present invention may be adapted for use with multiple fuel types, such as 17×17 fuel assemblies commonly used with pressurized water reactors, although the system and method may be utilized in other types of nuclear facilities such as boiling water reactors. For purposes herein, the terms “used nuclear fuel rods,” “nuclear fuel rods,” “fuel rods,” and the like may be used interchangeably. FIG. 1 shows a system 10 for consolidating used nuclear fuel rods. The system 10 is shown in a facility 11. As shown, fuel assemblies 16 (four fuel assemblies shown in FIG. 3) containing used nuclear fuel rods 18 (see FIGS. 2 and 3) are supported by a structure 12 in a recess 14 in facility 11. As shown, recess 14 is substantially filled with a liquid, such as water having a liquid surface 54 in close proximity to a support surface 56, with structure 12 and fuel assemblies 16 being submerged in the liquid. Fuel assemblies 16 include a top nozzle assembly 20 secured to the top of the fuel assembly structure. Three top nozzle assemblies 20 are shown in FIG. 3, with a top nozzle assembly 20 removed from the fourth fuel assembly 16, exposing the ends of rows 44 of fuel rods. As further shown in FIG. 1, a drive source 24 such as a robotic arm or robot that may be supported by support surface 56 may utilize tools that are selectively operably suspendable from the robot to achieve consolidation of the fuel rods 18 (FIG. 2). In one embodiment, the system 10 may utilize multiple drive sources, such as a second drive source 26 such as a robot. Exemplary tools include a top nozzle assembly removal tool 22, a tube cutter tool 28, a rod extraction gripping tool 36 and a rod gripping tool 50. Secured at the edges of recess 14 are docking stations 58 for each of the tools. When the system requires a specific tool, drive source 24 utilizes a standard “quick disconnect” connector (not shown) to selectively engage an end of the tool, after which the tool is operably suspendable from the robot during use, and then returned to its respective docking station 58. The system of the present invention, such as shown in FIG. 1, maintains a vertical separation 188 between a support surface 56 and a reference surface 190 in recess 14, depending upon the application. As a result of the vertical separation, the fuel rods 18 are always maintained vertically beneath reference surface 190 and continuously immersed beneath the surface 54 of liquid contained in recess 14. In one embodiment, the microprocessor controlled system may be automated to minimize human exposure to the fuel rods during the consolidation process. As used herein, the term “operably suspendable” and the like means that the elongated tools utilized by the drive source remain in a generally vertical position during use. That is, once a tool such as an end of the tool is operably connected to the drive source, during operation of the drive source, the orientation of the longitudinal axis of the elongated tool dangles from the drive source during manipulation of the tool by the drive source, essentially remaining unchanged relative to a wall of the recess. Stated another way, when the drive source manipulates or otherwise moves the tool, the end of the tool operably connected to the drive source remains generally vertically above an opposite end of the tool. As shown in FIG. 3, structure 12 includes waste-collection vessels 60, 62, an accumulator 46 and a consolidation canister 52. In one embodiment, waste-collection vessel 60 receives compressible waste, such as sleeves or portions of tubes associated with fuel assemblies 16. Waste-collection vessel 62 receives non-compressible waste, such as top nozzle assemblies 20 upon their removal from fuel assemblies 16. Accumulator 46 includes an inlet 64, a fuel rod feeder mechanism 66, an indexing conveyor 68, lateral transfer devices 70, 74 operatively connected to corresponding consolidation locations 72, 76, for receiving, arranging and consolidating fuel rods as will be discussed in additional detail below. Consolidated fuel rods at consolidation location 76 are then transported by rod gripping tool 50 (FIG. 1) to consolidation canister 52. As shown in FIGS. 4-6, top nozzle assembly removal tool 22, which removes top nozzle assembly 20 (FIG. 3) from fuel assembly 16 (FIG. 3) is now discussed. Top nozzle assembly removal tool 22 includes an end 23 opposite the end that is operatively connected to the drive source 24 (FIG. 1). End 23 includes an engagement feature 78 which matingly engages a corresponding feature 80 (FIG. 3) of fuel assembly 16 (FIG. 3) when drive source 24 (FIG. 1) vertically aligns and then directs top nozzle assembly removal tool 22 into mating engagement with fuel assembly 16 (FIG. 3). As further shown in FIG. 5, end 23 further includes a plurality of sleeve extractors 82 that are directed inside of retaining sleeves 32 positioned inside of tubes or guide tubes 34. Retaining sleeves 32 retain top nozzle assembly 20 connection to fuel assembly 16. One or more retention hooks 84, such as four (two retention hooks 84 are shown in FIG. 4) are actuated to lockingly engage corresponding internal features (not shown) of top nozzle assembly 20. In one embodiment, ends of retention hooks 84 outwardly pivot 85 such as by using a cam mechanism 86 to engage the corresponding internal features of top nozzle assembly 20. In one embodiment, a cam mechanism 86 operates simultaneously with a drive mechanism 83 urging downward movement of a plate assembly 88 carrying sleeve extractors 82 relative to end 23, resulting in sleeve extractors 82 being inserted inside of corresponding retaining sleeves 32. Once sleeve extractors 82 have been inserted inside of corresponding retaining sleeves 32, as shown in FIG. 6, a drive mechanism 90 actuates rods 92 to move axially relative to corresponding sleeve extractors 82 such that opposed portions of the ends of the sleeve extractors 82 laterally outward movement 94 or away from each other, resulting in the sleeve extractors 82 contacting the inner surface of the corresponding retaining sleeves 32 and thereby capturing the corresponding retaining sleeves 32. Once sleeves 32 have been captured by corresponding sleeve extractors 82, drive mechanism 90 actuates plate assembly 88 and sleeve extractors 82 away from guide tubes 34 to an intermediate position where retention hooks 84 remain engaged with the top nozzle assembly 20, permitting drive source 24 (FIG. 1) to disengage the top nozzle assembly 20 from fuel assembly 16, exposing ends of fuel rods 18 (FIG. 3) facing drive source 24. Stated another way, as collectively shown in FIGS. 1-6, the plurality of sleeve extractors 82 are positionable between a retracted position, an intermediate position, and an extended position, and the retention hook 84 is movable between an engaged position and a disengaged position for selectively engaging and disengaging the top nozzle assembly 20. The system provides in response to the top nozzle assembly removal tool 22 and the fuel assembly 16 being brought into aligned engagement, the plurality of sleeve extractors 82 being actuated from the retracted position toward the intermediate position, the retention hook 82 being simultaneously movable from the disengaged position toward the engaged position for engaging the top nozzle assembly 20. The system provides in response to the plurality of sleeve extractors 82 being actuated from the intermediate position toward the extended position, ends of the plurality of sleeve extractors 82 are directed inside of corresponding sleeves 32, the ends of the plurality of sleeve extractors 82 being actuated radially outward for engaging inner surfaces of the corresponding sleeves 32, The system provides in response to the plurality of sleeve extractors 82 being actuated from the extended position toward the intermediate position, the corresponding sleeves 32 being removed from the fuel assembly. The system provides in response to the plurality of sleeve extractors 82 being actuated from the intermediate position toward the retracted position, the retention hook 84 being simultaneously movable from the engaged position toward the disengaged position for disengaging the top nozzle assembly 20, when the top nozzle assembly 20 is positioned vertically above waste collection vessel 62. As a result of top nozzle assembly 20 being more dense than the liquid in the recess 14 (FIG. 1), the top nozzle assembly 20 falls into waste-collection vessel 62 by virtue of gravity. Once drive source 24 (FIG. 1) has positioned top nozzle assembly removal tool 22 over waste-collection vessel 60 (FIG. 3), drive mechanism 90 (FIG. 6) actuates rods 92 (FIG. 6) in an opposite direction, permitting the opposed ends of sleeve extractors 82 (FIG. 6) to move toward one another, thereby releasing the corresponding retaining sleeves 32 (FIG. 6). As a result of retaining sleeves 32 (FIG. 6) being more dense than the liquid in the recess 14 (FIG. 1), the retaining sleeves 32 fall into waste-collection vessel 60 by virtue of gravity. In one embodiment, end 23 (FIG. 6) of top nozzle assembly removal tool 22 (FIG. 1) includes nozzles for directing streams of liquid to ensure the retaining sleeves 32 (FIG. 6) are released from the tool. As shown in FIGS. 1 and 11, tube cutter tool 28 is now discussed. Tube cutter tool 28 includes an end 29 opposite the end that is operatively connected to the drive source 24 (FIG. 1), End 29 includes a plurality of cutters 30, with each cutter 30 including a cutter element 31 that is selectively movable between a retracted position and an extended cutting position in which cutter element 31 radially outwardly extends from the outer surface of the cutter. One or more rotary drive motors 96 (a pair of drive motors 96 are shown in FIG. 11), such as pneumatic drive motors simultaneously rotatably drive cutters 30. In operation, drive source 24 (FIG. 1) operatively engages or is operatively connected to tube cutter tool 28 positioned in docking station 58 as previously discussed. Drive source 24 operably suspends tube cutter tool 28, vertically aligning and then inserting each cutter 30 inside of a corresponding guide tube 34 of fuel assembly 16 (FIG. 3). Once inserted in the guide tubes 34, each cutter elements 31 is urged from the retracted position to an extended cutting position by a corresponding conventional drive mechanism 98 (only one drive mechanism 98 is schematically shown in FIG. 11). As cutter elements 31 are being urged toward the extended cutting position, drive motors 96 are urged into rotational movement, thereby cutting segments 35 from corresponding guide tubes 34. By maintaining cutter elements 31 in the extended cutting position, upon removal of tube cutter tool 28 from fuel assembly 16 (FIG. 3), segments 35 are retained by their respective cutter 30. Removal of segments 35 provides sufficient access for rod extraction gripping tool 36 (FIG. 1) associated with removing fuel rods 18 (FIG. 3) from fuel assembly 16 (FIG. 3). Once end 29 of tube cutter tool 28 is vertically positioned above waste-collection vessel 60, cutter elements 31 are urged from the extended cutting position to the retracted position, thereby permitting segments 35 to fall into waste-collection vessel 60 in a manner as previously discussed with retaining sleeves 32 (FIG. 5). Tube cutter tool 28 is then returned to its respective docking station 58 (FIG. 1). Referring to FIGS. 7-10 and 10A, rod extraction gripping tool 36 includes a frame 38 having a longitudinal axis 40 and a gripper array assembly 42 for gripping corresponding ends of a row 44 (FIG. 3) of fuel rods 18 (FIG. 3) in fuel assembly 16 (FIG. 3). In an exemplary 17×17 fuel assembly, up to 17 fuel rods 18 may be contained in row 44, although less than 17 fuel rods may be present. In one embodiment, gripper array assembly 42 may include a sufficient number of grippers 102 (FIG. 10) to accommodate rows of fuel rods in other fuel rod array arrangements that may contain less than 17 fuel rods. System 10 (FIG. 1) of the present invention has a controller such as a microprocessor that is well known. The number and position of each fuel rod in each row of fuel rods in each of the fuel assemblies is known by the system. Gripper array assembly 42 is selectively movable along frame 38 by a pair of ball screws 100 extending along frame 38. In one embodiment, linear guide rails are used in combination with ball screws 100. In one embodiment, ball screws 100 are driven by a servo motor with position feedback sent to the control system Gripper array assembly 42 includes a plurality of grippers 102, each gripper independently having a predetermined float length 106 along axis 40 capable of gripping an end of a corresponding used nuclear fuel rod 18 (FIG. 3) of a row 44 (FIG. 3) of used nuclear fuel rods, each of the used nuclear fuel rods capable of having a length differential relative to another used nuclear fuel rod of the row of used nuclear fuel rods; the length differential equal to or less than the predetermined float length 106. Stated another way, each gripper 102 is designed with passive compliance (“float”) in a vertical direction, such as with springs, to accommodate fuel rods 18 at various heights. The amount of compliance is equal to the amount of available space within the fuel assembly 16 (FIG. 3) for growth/movement, approximately 2.3 inches. In another embodiment, the amount of compliance may be greater than or less than 2.3 inches. As shown in FIG. 10A, an exemplary gripper 102 includes at least one shoulder 104 for contacting an end of a corresponding fuel rod 18 (FIG. 3). So long as the end of the fuel rod 18 falls within float length 106, gripper 102 can engage the outer surface of the corresponding fuel rod 18 for gripping/extracting the fuel rod. Each gripper 102 of gripper array assembly 42 includes a corresponding gripping mechanism 108, including an actuator 110 controlled by a controller 112 for selectively opening/closing the jaws of a respective gripper. As further shown in FIG. 10, each gripper 102 is operatively connected to a corresponding pin 114 that is subjected to a tensile load equal to a retraction force of a corresponding used nuclear fuel rod 18 (FIG. 3) applied along axis 40. Each gripper 102 includes a sensor (not shown) such as a proximity sensor in communication with controller 112 for feedback control of the system, with force sensing being achieved via strain gauges (not shown) located on the support pin 114 that is in in communication with controller 112 for providing feedback control. In response to retraction force 116 exceeding a first predetermined force that has been input into controller 112, a signal corresponding to the exceeded retraction force is provided to a controller in a manner that is well known, resulting in the gripper 102 releasing the end of the corresponding used nuclear fuel rod 18. In one embodiment, in response to the retraction force 116 exceeding a second predetermined force, which may be equal to or different from the first predetermined force, the gripper 102 becomes slidably disengaged from the end of the corresponding used nuclear fuel rod 18. That is, the gripping force applied by each gripper 102 to the outer surface of each used nuclear fuel rod 18 may be insufficient to continue to non-movably retain (i.e., grip) the fuel rods, and would “slide off” or slidably disengage from the fuel rods without the need for adjustment of the gripping force of the grippers. In other words, the above release/disengagement capabilities of the gripper from the fuel rods are safety measures in the event one or more fuel rods are “stuck,” i.e., requiring a retraction force that may damage the fuel rods. A specially configured tool (not shown) may be used to disengage such fuel rods. As further shown in FIGS. 7 and 8, rod extraction gripping tool 36 includes at least one pair of opposed guide rollers 118 (four pair of opposed guide rollers 118 are shown in FIG. 7) for guiding the row 44 (FIG. 3) of used nuclear fuel rods 18 (FIG. 3) along axis 40 relative to the frame 38 during removal of the row 44 of used nuclear fuel rods 18 from the fuel assembly 16 (FIG. 3). As shown in FIG. 8, each guide roller 118 includes a linkage 122 that is pivotably connected to an actuator 120 such as a pneumatic cylinder, thereby permitting the guide rollers 118 to be rotated out of the path of gripper array assembly 42 (retracted position) during operation of rod extraction gripping tool 36, then permitting the guide rollers 118 to be brought together (engaged position) to guide and support the row 44 (FIG. 3) of used nuclear fuel rods 18 (FIG. 3) while being collected by and removed from rod extraction gripping tool 36. Referring to FIGS. 1 and 12, rod gripping tool 50 includes an elongated frame 124 having a pair of gripping jaws or grippers 126 having corresponding gripping features 128 capable of selectively gripping one or more fuel rods 18 (FIG. 3), such as up to five fuel rods. In one embodiment, the gripping features are capable of gripping more than five fuel rods. As shown in FIG. 19, gripping features 128 includes a first portion 130 capable of gripping any combination of one, two or three fuel rods 18. Gripping features 128 also includes a second portion 132 adapted to grip a predetermined arrangement 134 of fuel rods 18, such as a row of three fuel rods in close proximity to a nested row of two fuel rods collectively defining a generally trapezoidal footprint, which predetermined arrangement 134 of fuel rods 18 having been consolidated to remove spacing between adjacent fuel rods in transverse directions 136, 138 such that the predetermined arrangement 134 of fuel rods is considered “nested.” An actuator 140, having a drive motor (not shown), such as a pneumatic parallel gripper actuator, that is adapted to drivingly move the pair of grippers 126 toward one another or away from one another to selectively engage and grip or selectively disengage predetermined arrangement 134 of fuel rods 18. Grippers 126 are selectively movable along a longitudinal axis 142 of frame 124 by a conventional drive mechanism, such as a ball screw 144 with linear guide rails (not shown). As shown in FIGS. 12 and 19, rod gripping tool 50 includes at least one pair of opposed guide rollers 146 in proximity to end 51 (FIG. 12) for guiding predetermined arrangement 134 of (FIG. 19) fuel rods along axis 142 (FIG. 19) relative to frame 124 during engagement (gripping)/disengagement of predetermined arrangement 134 of used nuclear fuel rods by/from the pair of grippers 126. As further shown in FIG. 12, each guide roller 146 includes a linkage 150 that is pivotably connected to an actuator 148 such as a pneumatic cylinder, thereby permitting the guide rollers 146 to be rotated out of the path of the gripper assembly during operation of rod gripping tool 50, then permitting the guide rollers 146 to be brought together (engaged position) to guide and support the predetermined arrangement (FIG. 19) of used nuclear fuel rods 18 (FIG. 3). Returning to FIG. 3, accumulator 46 is now discussed. FIG. 3 is a plan view of accumulator 46, with FIG. 13 being an upper perspective view of accumulator 46. As further shown in FIG. 13, once row 44 of fuel rods has been collected by rod extraction gripping tool 36, drive source 24 (FIG. 1) suspendedly aligns and matingly engages engagement features 154 of rod extraction gripping tool 36 with corresponding engagement features 156 of accumulator inlet 64. Once engaged, gripper array assembly 42 (FIG. 7) is directed along axis 40 (FIG. 7) of rod extraction gripping tool 36 for feeding or inserting row 44 of fuel rods into accumulator inlet 64 that is received by a fuel rod feeder mechanism 66. Once gripper array assembly 42 (FIG. 7) releases the row 44 of fuel rods into the accumulator inlet 64, drive source 24 (FIG. 1) suspendedly moves rod extraction gripping tool 36 to fuel assembly 16 (FIG. 3) to collect another row of fuel rods. As shown in FIGS. 13-15, fuel rod feeder mechanism 66 includes a shoe or carriage 158 supported by an elongated arm 160, which row 44 of fuel rods being laterally compressed in carriage 158, becoming a laterally compressed row 48 (FIG. 14). FIGS. 14-18 show the sequential steps in the operation of the accumulator 46. FIG. 14 shows carriage 158 laterally translating or moving laterally compressed row 48 along a slot 162 (FIG. 14) toward an indexing conveyor 68. As shown in FIGS. 13 and 14, previously laterally compressed fuel rods 164 are positioned in slot 162 (FIG. 14) between indexing conveyor 68 and laterally compressed row 48 (FIG. 14). Previously laterally compressed fuel rods 164 are secured opposite of indexing conveyor 68 by a feed mechanism 166. Once carriage 158 laterally translates laterally compressed row 48 of fuel rods into contact with previously laterally compressed fuel rods 164, fingers 168 (FIG. 15) of feed mechanism 166 move in a transverse direction 170 away from previously laterally compressed fuel rods 164, followed by feed mechanism 166 moving in travel direction 172 until past laterally compressed row 48, whereupon fingers 168 are moved in transverse direction 170 toward laterally compressed row 48, thereby securing laterally compressed row 48 of fuel rods against previously laterally compressed fuel rods 168. As shown in FIG. 16, previously laterally compressed fuel rods 164 are fed into adjacent recesses 174 of indexing conveyor 68 rotatably driven by a motor (not shown), becoming laterally spaced fuel rods 176. FIGS. 16 and 17 show a lateral transfer device 70 extending in a direction perpendicular to laterally spaced fuel rods 176. In FIG. 16, the lateral transfer device 70 is shown in a position ready to accept a predetermined number of laterally spaced fuel rods 176. A motor (not shown) cooperatively moves slots 180, 182 of fitting 178 in a direction transverse to laterally spaced fuel rods 176, to collect a predetermined number of laterally spaced fuel rods 176 from the indexing conveyor 68 in slots 180, 182, forming a predetermined arrangement 186 (FIG. 17) of fuel rods. In FIG. 17, the lateral transfer device 70 is shown laterally transporting a predetermined arrangement 186 of fuel rods 18 to the consolidation location 72. As shown in FIGS. 16 and 17, a lateral transfer device 70 includes a fitting 178 having a pair of slots 180, 182 extending in a direction parallel to laterally spaced fuel rods 176. For example, as shown in FIG. 17, slot 180 contains a pair of fuel rods 18 and slot 182 contains three fuel rods 18. In one embodiment, as few as one total fuel rod may be contained one or both of slots 180, 182, as needed to efficiently fill a consolidation canister 52. Lateral transfer device 70 laterally transports the predetermined arrangement 186 of fuel rods to consolidation location 72 for laterally compressing adjacent corresponding portions, i.e., the fuel rods contained in slots 180 and 182, of the predetermined arrangement 186 of fuel rods in a direction 172 (FIG. 15) which is parallel to the direction of movement of used nuclear fuel rods in the fuel rod feeder mechanism 66 (FIG. 13). As shown in FIG. 18, a transfer device 74 transports predetermined arrangement 186 of fuel rods from consolidation location 72 to a consolidation location 76. Lateral transfer device 74 laterally compresses adjacent corresponding portions, i.e., the two fuel rods formerly contained in slot 180 and the three fuel rods formerly contained in slot 182 of lateral transfer device 70, of the predetermined arrangement 186 of fuel rods in a direction 170 (FIG. 15) that is transverse to a direction of movement of fuel rods in the fuel rod feeder mechanism 66 (FIG. 13). As a result of this lateral compression in both mutually transverse directions 170, 172 (FIG. 15), predetermined arrangement 186 of fuel rods becomes predetermined arrangement 134 of fuel rods collectively defining a generally trapezoidal footprint, such that the predetermined arrangement 134 of fuel rods is considered “nested” as previously discussed. A method for consolidating used nuclear fuel comprises securing structure 12 in a recess 14 adjacent fuel assembly 16 containing used nuclear fuel rods 18 therein. The method provides fuel assembly 16 having a top nozzle assembly 20. The method further provides suspendably removing top nozzle assembly 20 from fuel assembly 16 with an elongated top nozzle assembly removal tool 22, exposing ends of the used nuclear fuel rods 18. The method further provides suspendably cutting and removing a predetermined segment 35 of corresponding tubes 34 in fuel assembly 16 with an elongated tube cutter tool 28 having a plurality of cutters 30. The method further provides suspendably removing a row 44 of used nuclear fuel rods 18 from fuel assembly 16 with an elongated rod extraction gripping tool 36. The method further provides selectively laterally arranging the row 44 of used nuclear fuel rods 18 in an accumulator 46, and suspendably moving the selectively laterally arranged used nuclear fuel rods 18 from the accumulator 46 to a consolidation canister 52 for receiving the selectively laterally arranged used nuclear fuel rods 18 therein. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
	claims	1. A device for capturing a shielding ball for a heavy water reactor, comprising:a head for separating shielding balls positioned inside an end shield of a calandria of a heavy water reactor to an outside of the end shield; anda mover for moving the head to the end shield of the calandria,wherein the head includesa head body,an opening former installed on the head body and configured to cut the end shield for creating an opening in the end shield, anda gate installed on the head body and configured to control an amount of the shielding balls discharged to the outside through the opening. 2. The device of claim 1, further comprisinga camera installed in the head body and setting coordinates of the opening former. 3. The device of claim 2, whereinthe gate has an aperture of which size is controllable. 4. The device of claim 2, whereinthe gate is slidable to control the amount of the shielding balls discharged to the outside. 5. The device of claim 2, whereina lower portion of the head body is installed to be inclined, andthe lower portion is movable to control a tilt angle of the lower portion. 6. The device of claim 3, further comprisinga sealer positioned on a front portion of the head body and and configured to contact the end shield for sealing. 7. The device of claim 3, whereinthe mover includes:a capture unit for capturing the shielding ball; anda transfer unit for moving the capture unit.
	summary
	description	In FIGS. 1 and 2 reference numerals 1, 1xe2x80x2 designate two strainers, which are mounted at the bottom of a reactor containment, whose wall is designated 2 and whose bottom is indicated at 3. The strainers are partly immersed in a pit or depression 4 and are separately connected to conduits 5 for the feeding of water into a cooling system (not shown). In the example, the nuclear power plant is thought to work with a compressed water reactor. This implies that under normal circumstances, the bottom of the reactor containment lacks water. However, at a possible shutdown water may accumulate at the bottom and create a water mass that entirely surrounds the strainers 1, 1xe2x80x2. In case the strainers were mounted to serve a boiling water reactor, the reactor containment would contain a bottom water mass in which the strainers would be fully immersed also under normal running circumstances. Onwards, the invention is described under the presumption that the strainers work in water. To each strainer 1 and 1xe2x80x2, respectively, is connected a measuring device whose main components consist of two pressure indicators or sensors 6, 6xe2x80x2, two tube conduits 7, 7xe2x80x2 and two vessels 8, 8xe2x80x2. As indicated in FIG. 3, the two vessels 8, 8xe2x80x2 are located at one and the same level, i.e., in a common horizontal plane. The first vessel 8 opens substantially directly towards the surrounding main water mass, while the second vessel 8xe2x80x2 is connected with the strainer 1 via a secondary tube conduit 9 that extends horizontally between the vessel and the strainer. Reference is now made to FIGS. 4 and 6, which show the nature of the two vessels 8, 8xe2x80x2 in more detail. In both cases, the vessel comprises a cylinder or a cylindrical wall 10 which is sealed at its opposed ends by means of gable walls 11, 11xe2x80x2. The cylinder is long and narrow and placed horizontally. In practice, the cylinder may have a diameter within the range of 80 to 100 mm and a length that is 3 to 5 times larger than the diameter. Therefore, the volume of the vessel may amount to about 2 to 4 dm3. In the proximity of one of the gable walls 11xe2x80x2 is provided a coupling means 12 connected to the upper part of the vessel, which coupling means may be connected to the previously mentioned tube conduits 7 and 7xe2x80x2, respectively. In the opposed gable wall 11xe2x80x2 is made an aperture 13 serving as an inlet, which aperture is placed near the bottom of the vessel and has a cross-sectional area which is considerably smaller than the cross-sectional area of the cylinder 10. At the vessel 8xe2x80x2 according to FIG. 5, a coupling means 12xe2x80x2 is connected to the aperture 13, which coupling means may be connected to the horizontal secondary tube conduit 9. Contrary thereto, at the vessel 8 according to FIG. 4, a short piece of tube 14 is connected to the aperture 13, which piece of tube is sealed at its free end by means of a gable 15. In the tube wall are recessed a plurality of small apertures 16, through which water can pass into the interior of the piece of tube and via the aperture 13 into the interior of the cylinder or the vessel. By the fact that the piece of tube includes these small apertures, which are substantially evenly distributed over the tube envelope, it is guaranteed that at least some of the apertures enable a liquid communication between the surrounding main water mass and the interior of the vessel, although some other would unintentionally be clogged by impurities. The water designated by 17 forms a surface or a mirror 18, above which there is an air or gas cushion 19. Each one of the two tube conduits 7, 7xe2x80x2 that are connected to the vessels 8, 8xe2x80x2 should have a limited diameter in order to guarantee that the total volume of the tube conduits becomes many times smaller than the volume of the vessels 8, 8xe2x80x2. In this way, it is guaranteed that the vessels receive a sufficient gas volume to keep the conduits filled with gas at all occurring pressure variations and water levels in the surroundings. In practice, the diameters of the tube conduits may be within the range 8 to 20 mm, preferably 10 to 15 mm, or most suitably 12 to 13 mm. As a practical example, it may be mentioned that the longest conduit 7xe2x80x2 may have a length of 5 meters and a diameter of 12,7 mm. Then the conduit obtains a volume of 0,63 dm3. At the same time, the vessel 8xe2x80x2 may have a volume of 3,24 dm3, i.e., a volume that is about 5,2 times larger than the volume of the tube conduit. In practice, the volume of the vessel should be 4 to 7, prefereably 5 to 6 times larger than the volume of the tube conduit. It is essential that the two vessels 8, 8xe2x80x2 be located in a common horizontal plane, so that differences in the statical liquid columns between the vessels do not influence measurements of pressure differences. More specifically, the two inlet apertures 13 shall be located at one and the same level. Assume that a shutdown occurs and that the strainers 1, 1xe2x80x2 start working in connection with an accumulation of water at the bottom of the reactor containment. The two vessels 8, 8xe2x80x2, which are located approximately on a level with the appurtenant strainer, will then be filled with water substantially simultaneously. Depending upon how high the surrounding main water mass rises in relation to the level of the vessels, a more or less high gas pressure will be created in the air cushion 19 and the interior of the tube conduits 7, 7xe2x80x2. These gas pressures may be detected by the sensors 6, 6xe2x80x2 (or by a gauge indicator for pressure differences common for both conduits). As long as the individual strainer, e.g. the strainer 1, is clean, equally large air or gas pressures prevail in the vessels 8, 8xe2x80x2. However, if impurities start clogging the apertures in the strainer, the water pressure in it will decrease in relation to the pressure in the surrounding main water mass. This will have the consequence that the water level 18 in the vessel 8xe2x80x2 sinks somewhat and that the gas pressure in this vessel is reduced. In other words, a difference arises between the gas pressures in the vessels 8, 8xe2x80x2 and the appurtenant tube conduits, which difference may be read by the sensors 6, 6xe2x80x2. Here, the magnitude of the gas pressure difference constitutes a measure of the degree of clogging of the strainer. When the pressure difference has reached a predetermined magnitude, reverse flushing or any other suitable cleaning of the strainer is initiated in a suitable way. In practice, the cleaning of the strainer may be accomplished either in an automatic way or by the sensors starting an alarm which in turn is utilized by the staff to manually start the cleaning operation. An essential advantage of the device according to the invention is that the vertical parts of the measuring legs, i.e., the tube conduits 7, 7xe2x80x2, always are kept dry, whereby the pressure measuring or indicating is not influenced by varying liquid columns. By the fact that the volume of the vessels 8, 8xe2x80x2 is many times larger than the volume of the tube conduits, this condition is guaranteed also if the level of the surrounding main water mass would rise to a considerable level above the vessels. From the individual strainer extends the tube conduit 9, which serves as a measuring leg, horizontally to the appurtenant reference level vessel; something that involves that the measurement is not influenced by the fact whether this tube conduit is wholly filled with water or contains air. The pressure difference at the difference pressure gauge indicator or the sensors is the same as at the measurement sites, independently of the surrounding pressure or liquid level. Sometimes wave formations or other sudden water motions may arise in the containment, which in extreme cases may lead to that water in an uncontrolled way is pressed up into the conduits 7, 7xe2x80x2. However, by the fact that these conduits have a pronounced, albeit limited diameter (e.g. 12 to 13 mm), it is guaranteed that the water is not withheld by the surface tension, but may flow back down into the vessel when the conditions return to normal. The invention is not restricted solely to the embodiment as described and shown in the drawings. Thus, in a wider aspect the invention is also applicable to the measuring of absolute gas pressures, i.e., without difference pressures being measured or indicated. In such cases, one single vessel may be included in a tube conduit and form a reference point or a reference vessel that forms a starting point from which a measurement may take place, independently of the level of the surrounding water or liquid mass. In this context it is underlined that the vessel, by being elongated and horizontal, guarantees that the level of the liquid enclosed in the vessel will vary within narrow limits even if the level of the surrounding liquid mass varies quite considerably.
	description	This application claims priority to U.S. Provisional Application No. 62/359,766, filed on Jul. 8, 2016, which is incorporated herein by reference in its entirety. There is disclosed a Hot Isostatic Press (“HIP”) system that is able to process radioactive materials, either manually or remotely. There is also disclosed a method of using such a HIP system to provide ease of maintenance, operation, decontamination and decommissioning. Hot Isostatic Pressing is a mature technology that is used to process many tons of material every day including castings and components made from powder metallurgy. These systems typically operate in an industrial setting and rely on the ability for direct operator intervention for almost every step. For example, hands-on processing is required for loading and unloading of the HIP system, maintenance of the supporting infrastructure, inspection, and if necessary, changing of critical seals at the location of the HIP vessel. In addition, regular interval inspection of the vessel to mitigate issues with potential gas leaks or vessel failures is critical. In addition, if the HIP system is operating in a radioactive environment the operators must be shielded from radiation. Thus, depending on the level of radiation or activity, remote location and/or remote operation of the HIP system may be necessary. Therefore, the ability for an operator to have hands on intervention is either not practically possible or must be done at considerable risks. In order to address and eliminate the foregoing problems, there is disclosed a nuclearized HIP system that not only considers the issues of safety, operating and maintaining a HIP in a radioactive environment, but also mitigates a majority of those problems. The disclosed nuclearized HIP system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art. In one aspect, the present disclosure is directed to a nuclearized hot-isostatic press (HIP) system comprising, a high temperature HIP furnace; a multi-wall vessel surrounding the furnace, wherein the multi-walled vessel comprises at least one detector contained between the walls to detect a gas leak, a crack in a vessel wall, or both; multiple heads located on top and underneath the furnace; a yoke frame; and a lift for loading and unloading a HIP can to the high temperature HIP furnace. In one embodiment, the at least one detector comprises a pressure detector, a gas flow detector, a chemical detector, a radiation detector, or an acoustic detector. There is also disclosed a method of using such a system to provide ease of maintenance, operation, decontamination and decommissioning. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. It is to be understood that both the foregoing general description and the FIGS. are exemplary and explanatory only and are not restrictive of the invention, as claimed. There are disclosed embodiments of a multi-wall HIP vessel for use in a toxic and/or nuclear environment and methods of using the same. In one embodiment, the multi-wall vessel comprises a dual walled vessel, and comprises a leak detection system between the vessel shells. By having a leak detection system located between the vessel shells, it is possible to measure gas leaking (e.g., from the seals) to give early indication that seals are losing performance and need to be replaced. Thus, in one embodiment, the leak detection system may be redundantly located at both ends of the vessel to give early detection of vessel cracking and/or leaking from the seals and thereby trigger safety systems. In some embodiments of a double wall/shell vessel, a small spiral groove may be machined into the vessel shell, such that the spiral groove is located between concentric vessels. In this way, the spiral grove can be machined either on the outside of the inner vessel or on the inside of the outer vessel's interior diameter. When the two concentric vessels are assembled via shrink fitting and the vessels are together the grove forms a channel or pathway from the top of the vessel to the bottom. By using this design, Applicants have found that if a through crack develops in the first wall of the vessel, the contained gas in the HIP will leak between the vessel walls, and the gas will travel the path of least resistance and flow into the grooved channel. In addition, the grooved channel forms a path to allow the leaked gas to travel to the ends of the vessel and remain contained. In one embodiment, the multi-walled vessels comprise end plates that bridge the interface of the multiple concentric vessel shells, which may allow the gas to be further directed via pipe work to a detection device to sense the leak. In one embodiment, sensing of a gas leak can be done using one or more techniques, including measuring a pressure increase between the vessel walls, gas flow change, or a chemical detector, such as a gas detector. Thus, in various embodiments, there is contained between the vessel walls of a multi-walled HIP vessel at least one of the following: a pressure sensor, a flow meter, a gas analyzer, a radiation detector, a Geiger counter, or combinations thereof. Upon the detection of an unwanted gas, such as by using one of the foregoing methods, the disclosed system is configured to open the HIP's vents to quickly reduce the pressure, preventing the crack from further growth. In addition, the control system could shut power to the furnace down in order to further prevent any increase in pressure via thermal expansion of the gas. In addition to detecting a gas leak between associated concentric vessels and/or the breach of a vessel wall, there is described a method of detecting a vessel crack. In one embodiment, vessel crack detection can be accomplished by fitting the vessel with acoustic sensors and/or vibration sensors that listen for the formation of cracks in the vessel walls. In one embodiment, this detection is accomplished by first establishing finger print signals of the vessel in stressed (maximum Pressure) and non-stressed (atmospheric pressure) states. Acoustic signals for the vessel may also be established for other intermediate process pressurizing and heating cycles of the system. The acoustic finger print signal may be established by transmitting a sound wave into the vessel wall and recording the response or transmission on the recording sensor. By using the foregoing protocols to establish a baseline acoustic “finger print” for the vessel, it is not only possible to determine if any crack develops under load, but the size of the crack can also be determined. In those situations in which the crack detected is longer than the critical crack length for the vessel design, action can be taken to shut the HIP down safely. In this way, the disclosed crack detection system, like the gas detection system, is configured to give real time data during the HIP cycle. In addition to the described gas detection and crack detection system, the described system also monitors the condition of the Yokes in real time with quantifiable data. For example, in some embodiments, strain gauges are used to determine excessive deformation due to crack growth, and any greater stretch than is normal will lead to the control system venting and shutting down the HIP, as is the case during acoustic monitoring. The system is capable of real time monitoring so prompt action may be taken immediately before a safety issue can occur. In some embodiments, the disclosed system comprises multiple independent detection and alarm control systems. As a result, the disclosed system provides diversity and varying levels and types of redundancy for temperature and pressure control by a variety of different techniques and equipment. In one embodiment, the HIP control system includes a programmable logic controller (PLC), or other similar programmable controller to control heating and pressurization rates, with control of automated vents to control gas pressure. An independent “hard wired” alarm control system ensures if the PLC malfunctions it cannot lead to an unsafe temperature and/or pressure condition that would damage the HIP system, since overheating of the furnace or the product could lead to both melting. As a result, the HIP system is configured to either manually or remotely load the disclosed system. With reference to the figures, FIG. 1A shows a general layout for a bottom loading HIP system according to one embodiment of the present disclosure. The exemplary embodiment of FIG. 1A comprises a multi-wall vessel. In this case, a dual wall vessel 110 is shown. The dual-walled vessel 110 has a “leak before burst” design to mitigate catastrophic failure. In the exemplary embodiment, the outer vessel contains any potential debris from becoming a projectile that may cause damage to the containment structure (hot cell) or personnel. The vessel material may comprise an ASME Code compliant material, and either is a stainless steel or ASME Code approved alloy that is coated (e.g. Ni coating/plating) for corrosion resistance and ease of decontamination in the event of radioactive material release from the product being processed. In particular, vessel material(s) may be selected based on their ductile failure mode as prescribed under ASME Code. Materials of construction may either be stainless steel or plated material to eliminate risk of corrosion and/or stress corrosion cracking. In the exemplary embodiment shown in FIG. 1A, the system further includes a HIP Frame 160, and a yoke 130 (multi-element). The yoke 130 shown in this embodiment comprises three elements. In one embodiment, the yoke 130 is designed to cover the entire span of the end closure opening. An advantage of the multi element yoke 130 design is that one element of the yoke 130 assembly can fail and the other elements are able to hold in the enclosures, allowing pressure relief yet containing components that may cause damage to the containment structure (hot cell) or personnel. FIG. 1A further describes a series of strain gauges 150 on the elements of yoke 130. The strain gauges 150 may collect and provide real time stress data during a HIP run. The strain gauges 150 are fitted to yokes 130 which in turn give online monitoring capability, e.g., the condition of deformation of the yokes. Therefore, in the exemplary embodiment an early indication of potential failure is provided. In some embodiments, the early indication may assist with the triggering of preventative safety systems (venting of pressure). In the exemplary embodiment shown in FIG. 1A, there is a bottom loading HIP system. The exemplary embodiment allows for bottom loading of the component to be pressed in the HIP can, represented by HIP can area 140. The HIP can area 140 can be raised using a variety of mechanisms 170, non-limiting examples of which include electric lift, hydraulic cylinders, pneumatic cylinders or machine screws, or a combination of all three. In another embodiment, there may be a dual-bottom closure. This design allows the furnace and thermal barrier to stay in place inside the vessel and the work load head to lower independently. For example, the assembly is able to travel out from under the vessel allowing the component to be loaded on the platform. Then, the loaded platform may travel back under the vessel and be raised up into the furnace by mechanisms 170. Turning to FIG. 1B, the outer lower head 175 of the system is shown. The furnace and thermal barrier (insulation) layer may be supported on this outer lower head 175. Additionally, power and signal data for the furnace may go through outer lower head 175. The outer lower head 175 can stay in the vessel while the inner lower head 180 is lowered to accept the part to be HIPed. In one embodiment, this component can lock in place via locking pins that can be automated to lock or release upon a signal command. With reference to FIG. 1C, the inner lower head 180 of the system is shown. The inner lower head 180 holds the load stand on which the component to be HIPed is placed (represented by HIP can area 140). The inner lower head 180, or portions thereof, is dimensioned to fit into the inner diameter of the outer lower head 175. Furthermore, inner lower head 180 has sealing elements that are engaged when inserted into the bore of the outer lower head 175. In turn, the outer lower head 175 is sealed against the bore of the vessel. In addition, the inner lower head 180 keeps the furnace and thermal barrier in place when the component to be pressed is loaded and unloaded. An advantage of this embodiment is that the inner lower head 180 increases the life of the furnace and thermal barrier. The inner lower head 180 has automated (pneumatic) pins/cylinders 182 that affix it to the outer lower head 175. For example, the outer lower head 175 is sized, dimensioned, and/or configured to operably couple and uncouple to the inner lower head 180 via the pins/cylinders 182. In this embodiment, when raised, the inner lower head 180 engages with the outer lower head 175 and the pins lock to it. The ram can then be lowered allowing for a path for the yoke to be moved over the top head of the system 120 (shown in FIG. 1D) and lower heads 175, 180 of the vessel 110 Turning to FIGS. 2A-2C, different perspectives of a nuclearized HIP system according to the present disclosure, including a top view (FIG. 2A), an end view (FIG. 2B), and a front view (FIG. 2C) are shown. With reference to FIG. 2A, showing a top view of the vessel 110 and system, it is noted that for the part loading guide 210, if the part is being loaded by overhead crane it is centralised to be placed on the load platform of the inner lower head. FIG. 2C shows the inner lower head 180 (see FIG. 1C) can be pushed, pulled or driven on tracks or guides 220. When it is moved under the vessel bore to a region corresponding to the vessel bore's center-line the inner lower head 180 can be raised by mechanisms 170 (See FIG. 1A), such as a cylinder or motor screw that are configured to drive upwards into the vessel 110. Once in place, the pins/cylinders 182 lock the head in place and the elevator ram or drive retracts and the yoke is moved over the region corresponding to the center-line of the HIP vessel. FIG. 2C also shows the yoke 130 in a closed position 230A and an open position 230B. In the exemplary embodiment, the mechanism 170 (lifting cylinder) rises upward from a pit in the floor. However, mechanism 170 may alternatively be mounted in line with the vessel 110 and pull/push the head up and clear a pathway of the yoke 130 to move across. FIG. 3 shows a vessel on a stand and main with additional features and/or elements. These features/elements may include a dual walled vessel 310, with leak detection plates on both ends of the vessel 315. The exemplary embodiment further shows a thermal barrier layer, such as an insulation layer 320, surrounding the furnace 330. The load platform 340, may hold, load, and unload the HIP can. In the exemplary embodiment, the yoke is in an open position 230B state. Other elements shown in FIG. 3 include the outer lower head 175 (from FIG. 1B), as well as the inner lower head 180 (from FIG. 1C), located on top of head carrier 370. In addition, pins/actuators 350, which hold the outer lower head 175 (furnace head) up are shown. Finally, there is shown a outer lower head push/pull apparatus 360 that is configured to removably couple to the inner lower head 180 and push/pull the inner lower head 180 when it is in the down position in a direction perpendicular to the raising/lowering direction of mechanism 170. This may be particularly advantageous, for example, when the lower furnace/thermal barrier is lowered for maintenance or repair to an external position. In the exemplary embodiment, the outer lower head push/pull apparatus 360 may be uncoupled when the inner lower head comes into a contact position and is ready to be raised. The coupling/uncoupling may occur in a variety of ways. For example, when the pins are disengaged the inner lower head 180 may be lowered thereby causing the furnace head to lower simultaneously. From the lowered position, the inner lower head 180 and or the furnace head can be moved to an external position from the system thereby allowing access to perform maintenance. As shown, there is described a nuclearized hot-isostatic press (HIP) system comprising: a high temperature HIP furnace; a multi-wall vessel surrounding the furnace, wherein the multi-walled vessel comprises at least one detector contained between the walls to detect a gas leak, a crack in a vessel wall, or both. The at least one detector may comprise a pressure detector, a gas flow detector, a gas analyzer, a radiation detector, or an acoustic detector. There is also described a system that comprises multiple heads located on top and underneath the furnace, including a top head, an outer lower head, and an inner lower head. In one embodiment, the outer lower head is configured to allow the furnace to sit on it. It can also be locked to the vessel while the inner lower head can be lowered to accept the part to be HIPed. In one embodiment, the inner lower head is configured to hold a stand on which the component to be HIPed is placed, and is configured to allow it to fit within the inner diameter of the outer lower head. The inner lower head may also contain at least one seal to form a seal with the outer head, and/or to keep the furnace and thermal barrier in place when the component to be pressed is loaded and unloaded. The inner lower head may also comprise at least one pneumatic pin, cylinder or clamp that couples it to the outer lower head. Also, the top head is typically located on top of the furnace and sits in the bore of the vessel. In one embodiment, described a nuclearized HIP system comprises a yoke and a yoke frame. The yoke may comprise multiple elements and is configured to allow the yoke frame to remain operational upon the failure of one element of the yoke. In another embodiment comprises at least one strain gauge on the yoke configured to collect and provide real time stress data during the HIP run. The described a nuclearized hot-isostatic press (HIP) system further comprises a lift mechanism configured to load and unload a HIP can to the high temperature HIP furnace. Non-limiting examples of the loading element include an electric lift, hydraulic cylinders, pneumatic cylinders, machine screws, or a combination thereof, to load and unload a HIP can from outside the HIP system to the HIP furnace. In an embodiment, the loading element comprises a bottom loading design, and the system may further comprise a dual bottom closure design to allow the furnace and thermal barrier to stay in place inside the vessel while the HIP'ed component is removed from the system. In an embodiment, the multi-wall vessel comprises two concentric vessels. This embodiment may also contain at least one groove between the vessels, wherein said groove is contained in the outside of the inner vessel or on the inside of the outer vessel, or both, and forms one or more pathways for gas located between the vessel walls to travel. The nuclearized HIP system may also comprise at least one thermal barrier layer located between the furnace and the multi-walled vessel In one embodiment, the furnace of the HIP system is locked in place for normal operation with spring loaded catches. The latches can either be manually or automatically actuated. In another embodiment, there is disclosed a method of hot isostatic pressing a material containing at least one heavy metal, toxic, or radioisotope using the nuclearized HIP system described herein. Non-limiting examples of such materials include all known constituents of spent nuclear fuel, mercury, cadmium, ruthenium, cesium, magnesium, plutonium, aluminum, graphite, uranium, and other nuclear power plant decommissioning wastes, zeolitic materials, and contaminated soils. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope of the invention being indicated by the following claims.
	claims	1. A nuclear fuel assembly comprising:a top nozzle;a bottom nozzle;a plurality of elongated guide thimbles extending axially between and attached to the top nozzle and the bottom nozzle, at least some of the plurality of guide thimbles having a tubular sheath that extends a majority of the length of the corresponding guide thimble with a lower end of the sheath capped by a lower end plug having an aperture extending axially there through; anda tube-in-tube dashpot having an axially extending sidewall disposed within a lower portion of the tubular sheath with an opening in the sidewall of the dashpot aligned with an opening in the tubular sheath, wherein the opening in one of the sidewall of the dashpot or the tubular sheath is oblong extending partially around a circumference of the one of the sidewall or the tubular sheath with a greater diameter of the oblong opening extending in the circumferential direction. 2. The nuclear fuel assembly of claim 1 wherein the tube-in-tube dashpot has a lower end cap with an aperture extending axially there through which aligns with the aperture in the lower end plug of the tubular sheath. 3. The nuclear fuel assembly of claim 2 including a fastener that extends through the bottom nozzle, through the lower end plug of the tubular sheath and into the lower end cap of the tube-in-tube dashpot, attaching the guide thimble and the tube-in-tube dashpot to the bottom nozzle. 4. The nuclear fuel assembly of claim 3 wherein the aperture in the lower end cap of the tube-in-tube dashpot is threaded and mates with a corresponding thread on the fastener. 5. The nuclear fuel assembly of claim 1 wherein the opening in the one of the sidewall or the tubular sheath comprises a plurality of circumferentially spaced oblong openings formed approximately at the same elevation. 6. The nuclear fuel assembly of claim 5 wherein the opening in the one of the sidewall or the tubular sheath comprises two circumferentially spaced oblong openings formed approximately at the same elevation. 7. The nuclear fuel assembly of claim 1 wherein the opening in the other of the tubular sheath or the sidewall is circular and overlaps a portion of the oblong opening in the one of the sidewall of the tube-in-tube dashpot or the tubular sheath. 8. A modular reactor having a primary circuit substantially contained within a pressure vessel that houses a core comprising fuel assemblies at least some of which include:a top nozzle;a bottom nozzle;a plurality of elongated guide thimbles extending axially between and attached to the top nozzle and the bottom nozzle, at least some of the plurality of guide thimbles having a tubular sheath that extends a majority of the length of the corresponding guide thimble with a lower end of the sheath capped by a lower end plug having an aperture extending axially there through; anda tube-in-tube dashpot having an axially extending sidewall disposed within a lower portion of the tubular sheath with an opening in the sidewall of the dashpot aligned with an opening in the tubular sheath, wherein the opening in one of the sidewall of the dashpot or the tubular sheath is oblong extending partially around a circumference of the one of the sidewall or the tubular sheath with a greater diameter of the oblong opening extending in the circumferential direction. 9. The modular reactor of claim 8 wherein the tube-in-tube dashpot has a lower end cap with a threaded aperture extending axially there through which aligns with the aperture in the lower end plug of the tubular sheath. 10. The modular reactor of claim 9 including a threaded fastener that extends through the bottom nozzle, through the lower end plug of the tubular sheath and into the lower end cap of the tube-in-tube dashpot, attaching the guide thimble and the tube-in-tube dashpot to the bottom nozzle. 11. The modular reactor of claim 10 wherein the aperture in the lower end cap of the tube-in-tube dashpot is threaded and mates with a corresponding thread on the fastener. 12. The modular reactor of claim 8 wherein the opening in the one of the sidewall or the tubular sheath comprises a plurality of circumferentially spaced oblong openings formed approximately at the same elevation. 13. The modular reactor of claim 11 wherein the opening in the one of the sidewall or the tubular sheath comprises two circumferentially spaced oblong openings formed approximately at the same elevation. 14. The modular reactor of claim 8 wherein the opening in the other of the tubular sheath or the sidewall is circular and overlaps a portion of the oblong opening in the one of the sidewall of the tube-in-tube dashpot or the tubular sheath.
	abstract	A foil is formed on a given substrate, then, peeled off of the substrate and floated on the water surface charged in a tank. The surface level of the water is decreased to contact the foil to a folding plate of a jug substrate and thus, fold the foil at the folding plate in two. The two surfaces of the foil opposing each other are laminated along a foil forming-supporting plate within a laminating region. The thus laminated foil is dried and annealed except the area in the vicinity of the foil forming-supporting plate, and then, cut along the folding plate, a foil acceptor and a supporting plate, to provide a stripping foil which can be supported by itself.
047939478	abstract	The present invention relates to a method and an apparatus for producing a waste package of radioactive waste containing particles of radioactive waste material of low modulus of elasticity, particles of radioactive waste material of high modulus of elasticity, and a solidifying agent in which the particles of radioactive waste material of low modulus of elasticity and the particles of radioactive waste material of high modulus of elasticity are fixed in an almost uniformly dispersed state. According to this invention, the radioactive waste generated from nuclear power plants can be greatly reduced in volume and also a waste package of radioactive waste with high strength and excellent water resistance can be obtained.
	claims	1. An apparatus for killing pathogenic and non-pathogenic organisms using low-energy x-rays, the apparatus comprising: a shielding assembly that maximizes internal deflections to prevent the x-rays from escaping the apparatus enclosing an irradiation zone having inlet portion and an outlet portion and defining a passageway therebetween, the passageway defining a path of travel for articles to be irradiated between the inlet and outlet portions; means for substantially continuously moving the articles to be irradiated through the irradiation zone at at least a first velocity; and an irradiation chamber that houses at least one x-ray source disposed within the passageway between the inlet and outlet portions in the path of travel of the articles to be irradiated, each at least one x-ray source having a first power level capable of emitting x-rays for a period of time sufficient to provide at least a predetermined dose of radiation to an article and capable of a maximum continuous power output at 100% duty cycle that is selected from within range of from approximately 16 kW to approximately 20 kW to thereby continuously emit low-energy x-rays having energies of from approximately 10 KeV and up to a maximum of approximately 440 KeV,wherein the at least one x-ray source comprises: an x-ray tube having a longitudinal axis with a power of 16 kW that emits a continuous spectrum of low energy x-rays; wherein the low-energy x-rays emitted by the at least one x-ray tube to which the at least one article is exposed are primarily bremsstrahlung-type x-rays characterized by a continuous range of energies from that of the most energetic electron downwards having energies of 220 Ke V; a cathode having a tungsten filament; a non-rotating anode including a target selected from the group consisting of tungsten, copper, aluminum, gold, platinum, strontium, titanium, and rubidium; and a beam window parallel to the target disposed a predefined distance from the target and perpendicularly disposed with respect to the longitudinal axis of the x-ray tube. 2. The apparatus of claim 1, wherein the means for substantially continuously moving the articles to be irradiated through the irradiation zone at least a first velocity comprises: a conveyor system adapted for the movement therethrough of a plurality of articles to be irradiated at a first velocity; at least one conveyor that moves a plurality of articles at least a first velocity through the passageway defined between the inlet and outlet portions of the irradiation zone; at least one open portion accessing an article transported along the at least one conveyor; and a closed portion, housed within the irradiation zone. 3. The apparatus of claim 2, wherein the at least one conveyor forms a closed-loop when moving between the inlet and outlet portions of the irradiation zone and wherein the closed-loop has a profile selected from the group consisting of a T-shaped profile, an oval-shaped profile, and an oval-spiral profile. 4. The apparatus of claim 2, wherein the conveyor forms a two level linear path between the inlet and outlet portions of the irradiation zone. 5. The apparatus of claim 1, wherein the x-ray source further comprises: a plurality of x-ray tubes each capable of exposing an article to a continuous spectrum of energies from approximately 10 KeV up to a maximum of up to 440. 6. The apparatus of claim 5, wherein the plurality of tubes comprise: a first and a second set of tubes, wherein the second set of tubes opposes the first set of tubes across a conveyor having a central longitudinal axis arranged within the irradiation chamber. 7. The apparatus of claim 6, wherein the selected plurality of opposing tubes further comprise: an in-line configuration along the conveyor central longitudinal axis. 8. The apparatus of claim 6, wherein the plurality of selected opposing tubes comprise: an off-center configuration wherein each of the first and second sets of opposing tubes are spaced a predetermined distance laterally off-center from the central longitudinal axis of the conveyor. 9. The apparatus of claim 5, wherein the plurality of tubes further comprise: a first and a second set of tubes, wherein the first set of tubes is disposed above a conveyor having a central longitudinal axis and are adapted to emit x-rays downwardly towards an upper surface of an article being irradiated and towards an upper side of the conveyor, and wherein a second set of tubes are offset longitudinally along the conveyor central longitudinal axis from the first set of tubes and are adapted to emit x-rays towards a lower surface of an article being irradiated and towards a lower side of the conveyor. 10. The apparatus of claim 9, wherein the plurality of tubes further comprise: an in-line configuration along the longitudinal axis of the conveyor. 11. The apparatus of claim 9, wherein the plurality of tubes further comprise: an off-center configuration wherein each of the first and second sets of off-set tubes are spaced a predetermined distance laterally off-center from the central longitudinal axis of the conveyor. 12. The apparatus of claim 1, wherein the shielding assembly further comprises: an external shield adapted to enclose the irradiation zone; a first internal shield housed by the external shield that encloses the irradiation chamber; and a second internal shield integrally formed with the external shield to partition an interior region of the irradiation zone from an open portion of an open region of a conveyor system defining the means for substantially and continuously moving the articles to be irradiated through the irradiation zone at least a first velocity.
	summary
H00002682	claims	1. A closed magnetic field line plasma confinement device, comprising: a plurality of linear magnetic plasma confinement sections each comprising an identical plurality of axisymmetric assemblies of plasma confinement mirror segments connected in series to generate magnetic fields having continuous magnetic field lines extending through said confinement sections for confining a plasma, a each of said segments including an annular mirror field plasma confinement means of the bumpy type including an microwave cavity formed by an enlarged diameter portion of a vacuum containment vessel confining tne plasma along said confinement section wherein a hot electron ring is formed about an enlarged diameter portion of the magnetic field lines of each mirror field segment to provide magnetohydrodynamic stability of a confined plasma; a plurality of curved sections formed of curved generally cylindrical sections linking said plurality of linear confinement sections into a generally polygonal magnetic plasma containment vessel; and solenoid coil means disposed about each of said plurality of curved sections for generating a solenoidal magnetic field extending through each of said curved sections, said solenoidal magnetic fields being sufficiently stronger than the average magnetic fields generated in said plurality of linear confinement sections to generate compressed, continuous field lines within a smaller confinement diameter than that of said linear confinement sections and aligned to form continuous magnetic field lines with those of said linear sections so that the radial drift of confined plasma particles passing through said curved sections is minimized, thereby providing stability of the confined plasma. 2. The plasma confinement device as set forth in claim 1 wherein said plurality of linear plasma confinement sections and said plurality of curved sections is four thereby forming a generally square plasma confinement device. 3. The plasma confinement device as set forth in claim 2 wherein each of said curved sections has a length substantially shorter than the length of said linear sections. 4. The plasma confinement device as set forth in claim 3 wherein each of said curved sections are 90.degree. sections having a common radius over the length thereof and displaced radially outward with respect to the axis of adjacent linear sections so that the contours of constant magnetic fields in the midplane of the end segments of adjacent linear sections are aligned on the same set of field lines on which they are formed in the linear sections. 5. The plasma confinement device as set forth in claim 4 wherein said solenoid coil means includes a plurality of circularly shaped, planar coils uniformally diposed about said corner sections.
	abstract	It is an object of the present invention to provide a specimen observation method, an image processing device, and a charged-particle beam device which are preferable for selecting, based on an image acquired by an optical microscope, an image area that should be acquired in a charged-particle beam device the representative of which is an electron microscope. In the present invention, in order to accomplish the above-described object, there are provided a method and a device for determining the position for detection of charged particles by making the comparison between a stained optical microscope image and an elemental mapping image formed based on X-rays detected by irradiation with the charged-particle beam.
	description	This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention. The present disclosure relates generally to nuclear reactors, nuclear target assemblies, and nuclear methods. More specifically, the present disclosure relates to Pu-238 production target assemblies, reactor assemblies, and designs, and generally relates to commercial reactors as well. Nuclear reactors have been used to produce commercially valuable products. For example, isotopes for medical industrial use and plutonium have been produced using nuclear reactors. Specific grades of plutonium have also been produced as well. One such avenue to production of Pu-238 is the nuclear reaction of americium (Am) and/or neptunium (Np) to produce Pu-238. It is clear that a Pu-238 source is more necessary than ever as in at least one example, Pu-238 can provide the heat source for radioisotope power systems and radioisotope heater units used in NASA space exploration missions and in national security applications. Kilogram-scale production of Pu-238 has not occurred in the United States since 1988, but small quantities of Pu-238 from process demonstrations have been produced at Oak Ridge National Laboratory using the high flux isotope reactor research reactor and theorized at the Idaho National Laboratory using the advanced test reactor research reactor. NASA missions requiring nuclear power have been relying on existing inventories and purchases from Russia, which were suspended in 2009. There are no known sources of Pu-238 outside the U.S. and Russia stockpiles; thus, the total amount available for mission use is fixed. The quantity of Pu-238 that can be produced by research reactors in the United States is limited, constraining the future use of Pu-238 for national security, NASA, and international space agencies. Although the European Space Agency is investigating the use of Am-241 for radioisotope heat and power sources due to its availability in the United Kingdom from aged civilian plutonium stockpiles, Pu-238 is the preferred isotope for space applications. High-power production reactors have been shut down in the U.S., leaving only the high-power reactors remaining being commercial reactors. Commercial reactors operate at a much higher temperature, and the previous Pu-238 production target designs are not compatible with commercial reactor operating schemes. For example, targets placed in commercial reactors must be able to survive condition 1, 2, and 3 events and not contribute any adverse consequences to the outcome of a condition 4 accident. As mentioned, past techniques used for producing kilogram quantities of Pu-238 are based on the irradiation of aluminum targets containing neptunium-237 oxide in a nuclear reactor. Post irradiation, aluminum can be dissolved in a caustic bath followed by acid dissolution of the remainder of the target. Following recovery and purification, Pu-238 can be precipitated from a nitrate solution, calcined to an oxide, and processed as a powder into heat source pellets. However, powder processing of Pu-238 oxide is known to create dispersible particles, resulting in gross contamination of glove box equipment, loss to holdup, and significant fractions requiring recycling. In addition to the assemblies provided, a method is also provided that details a sol-gel process for fabricating spheres or microspheres of Np-237 oxide and/or Pu-238 oxide. This allows for the irradiation techniques described herein as well as new and additional irradiation techniques. It reduces contamination during Pu-238 oxide handling and improves Pu-238 oxide processing efficiency, which allows for new Pu-238 oxide heat sources. The present disclosure provides reactor assemblies, target assemblies, and methods that in certain circumstances can meet the performance metrics that permit use in a commercial reactor. Further, embodiments of the disclosure provide features that can enhance material recovery efficiencies following irradiation, and this may reduce waste volumes compared to prior legacy target assemblies. The present disclosure provides reactor assemblies, reactor target assemblies and methods that can be used to produce Pu-238 from, for example, Am or Np spheres. Reactor target assemblies are provided that can include a housing defining a perimeter of at least one volume and Np or Am spheres within the one volume. Reactor assemblies are provided that can include a reactor vessel and a bundle of target assemblies within the reactor vessel, at least one of the target assemblies comprising a housing defining a volume with Np or Am spheres being within the volume. Methods are also provided that can include irradiating Np or Am spheres, such as within a nuclear reactor, then removing the irradiated spheres from the irradiation location and processing the irradiated spheres. This disclosure is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). The present disclosure will be described with reference to FIGS. 1-11. Referring first to FIG. 1, a group of spheres 10 is shown, and these spheres represent americium and/or neptunium spheres that can be produced and utilized in accordance with example embodiments of the present disclosure. These spheres can be considered microspheres that are flowable and easily handled, allowing them to be simply poured into complex or simple target geometries prior to irradiation, and then poured out after irradiation. Complex geometries may allow for improvements in isotopic purity of Pu-238 products and/or mitigation neptunium fission. These spheres may be loaded into refractory materials to form part of a target assembly that is survivable at elevated reactor or commercial reactor temperatures and can also withstand accident-scenario temperatures. These spheres can be produced by sol-gel process, and this sol-gel process can be used to generate Np-237, Pu-239, and/or Pu-238 as well as Am-241 spheres. The process can be initiated by creating concentrated solutions of a nitrate of the desirable element such as 237Np(IV) nitrate, 239Pu(IV) nitrate, and/or 238Pu(IV) nitrate that benefit from free acid concentrations below 4M. Valence adjustments can be made using a reductant such as hydrazine for neptunium and hydrogen peroxide for plutonium, for example. Other reducing agents may also be used to obtain the tetravalent state of neptunium and/or plutonium. Pre-chilled Np-237, Pu-239, and Pu-238 nitrate precursor feed solutions can be mixed with pre-chilled precursor aqueous solutions containing both 3.18M hexamethylenetetramine (HMTA) and 3.18M urea and chilling same to approximately 0° C. Conditions for formation of gels benefit from high neptunium or plutonium concentrations, HMTA, and urea concentrations in precursor solutions. Typically, the HMTA and urea can be dissolved near their combined solubility limit at approximately 3.2M. Neptunium or plutonium feed solutions are prepared by re-wetting moist neptunium or plutonium nitrate crystals with nitric acid at a concentration of ≤4M and neutralized hydrazine or hydrogen peroxide to obtain a [Np(IV)] or [Pu(IV)] near 2M. Hydroxide may be added to the nitrate solutions to eliminate free acid and increase the solution pH. Hydroxide addition can be limited to that which keeps the initial mixed feed solution pH below that which initiates precipitation. Mixed feed can be defined as the combined, chilled metal nitrate solution and HMTA/urea solution. It is believed that operable conditions are broader than the conditions described herein, with more dilute metal nitrate and HMTA/urea solutions being satisfactory, but higher temperatures and longer heating durations being utilized to provide the gel. Additionally, as solutions become too dilute, resultant gels can become weaker to the point of becoming viscous suspensions. Gelation does not appear to be sensitive to the urea/Np ratio so long as adequate urea is present (>1 mole urea per mole Np) to prevent gelation while chilled near 0° C. Gelation can be sensitive to the HMTA/Np ratio, with low ratios (<1) resulting in weak gels and high ratios (>3) resulting in gelation while chilled near 0° C. (referred to as premature gelation). Table 1 below provides an initial gelation result at a hydroxide to neptunium ratio of 0.75 and HMTA to neptunium ratios ranging from 1.5-2.5. At this concentration of precursor solutions and hydroxide content, an HMTA ratio of 2.0 can be utilized for gelling. TABLE 1Quality of Np-237 Gels vs. HMTA ContentOH−/Np0.75HMTA/Np1.5U1.75S2.0 S2.25S2.5PU = Unsatisfactory gelS = Satisfactory gelP = Premature gelation= Ideal condition With regard to Pu-239 gels, high plutonium, HMTA, and urea concentrations in precursor solutions can be utilized. Typically, HMTA and urea can be dissolved near their combined solubility limit at approximately 3.2M. Plutonium feed solutions can be prepared by re-wetting moist plutonium nitrate crystals with nitric acid at a concentration of ≤4M and hydrogen peroxide to obtain a [Pu(IV)] near 2M. Hydroxide may be added to the Pu-239 nitrate solution to reduce free acid and increase the solution pH. Preferably, hydroxide addition can be limited to that which keeps the initial mixed feed solution pH below 4.5. The mixed feed can be defined as above. Gelation can be sensitive to the HMTA/Pu ratio, with low ratios (<1) resulting in weak gels and high ratios (>3) resulting in gelation while chilled near 0° C. (referred to as premature gelation). Table 2 provides initial gelation results at a hydroxide to plutonium ratio of 0.75 and 1.0, and HMTA to plutonium ratios ranging from 1.5-2.5. At this concentration of precursor solutions and hydroxide content, an HMTA ratio of 2.25 and OH−/Pu ratio of 0.75 can be utilized for gelling. TABLE 2Quality of Pu-239 Gels vs. HMTA and Hydroxide ContentR-Value/OH−/Pu0.751.01.5UU1.75SS2.0SS2.25 SS2.5SPU = Unsatisfactory gelS = Satisfactory gelP = Premature gelation= Ideal condition Pu-238 gels can be generated using a similar approach to that described above with reference to Pu-239. However, in comparison to Pu-239, Pu-238 can generate decay heat and radiolysis products. Thus, Pu-238 in nitric acid may form bubbles and create radiolysis products causing oxidation to 238Pu(VI) and may require more reductant than an equivalent quantity of Pu-239. Neptunium, plutonium, and/or americium stock materials are converted to an aqueous nitrate solution. The valence state of the neptunium or plutonium is generally reduced to Np(IV) or Pu(IV) using a reducing agent such as hydrazine or hydrogen peroxide. The starting solution is acidic but can be partially neutralized in pH, such as by the addition of concentrated ammonium hydroxide solution or exposure to ammonium hydroxide vapors. As described above, the HMTA to urea concentration can be 3.18M and mixed with the metal nitrate solution in a 2:1 HMTA to metal mole ratio. Prior to mixing and once mixed, these solutions are chilled to a temperature between their freezing point and a temperature that would cause gelation. Generally, the solutions are chilled between −5° C. and 0° C. This mixture of metal nitrate and organic solution can be metered through a needle in a 2-fluid nozzle that is chilled to prevent gelation in the nozzle. The microspheres formed by the nozzle can be heated to about 80° C. in a forming fluid such as oil and then flowed into a mesh basket for collection of gelled microspheres. According to example implementations, upon production, these gelled spheres can be from 20 to 1000 μm in diameter and/or from 10 to 500 μm in diameter upon drying. Generally speaking, the gelled microspheres containing neptunium, plutonium, and/or americium may be washed to remove the forming fluid and excess reagents. As an example, the gelled spheres can be washed with a solvent, such as trichloroethylene and isopropyl alcohol, or an emulsifying agent to remove oil forming fluids and also washed in a basic solution such as an ammonium hydroxide solution to leach impurities. Prior to drying, there can be a hydrothermal treatment to remove organic impurities and/or excess water from the gelled spheres by heating the gelled and washed spheres to about 200° C. After the hydrothermal treatment, the microspheres may be rinsed with water and then dried, producing the metal oxide of the desired materials such as the neptunium oxide, the americium oxide, or the plutonium oxide. Spheres may be heat treated and pressed into a pellet. In particular embodiments neptunium and/or americium spheres may be treated with less heat than plutonium spheres. This lower heat treatment can improve material recovery after irradiation. Referring next to FIG. 2, target assembly 20 according to an embodiment of the disclosure is provided. As can be seen, target assembly 20 includes a housing 22 that defines a volume 24. At least part of this volume 24 may be occupied by other materials, including the Np or Am spheres 26. This housing can be at least partially stainless steel or zircaloy, for example, in certain circumstances, but typically sufficient to be utilized in a commercial reactor. As can be seen in this one embodiment, spheres 26 can occupy a portion of the interior volume 24. Referring next to FIG. 3, a cross-section of a portion of target assembly 20 is shown detailing the portion 26 identifying the spheres contained within the target assembly. Referring next to FIG. 4, a pop-out or exploded view of the spheres within target assembly 20 is shown, demonstrating a geometry within the target assembly 20. This geometry can be brought about by a ceramic insert 28, and this ceramic insert may have a ceramic cap portion 30, as well as a core portion 32. This ceramic portion can be a graphite or carbon for example, and in accordance with at least one example implementation, can have a circular cross-section as well as the target assembly having a circular cross-section. Referring to FIG. 5, a detailed view of cap 30 is shown with a recess 34 configured to receive a core of ceramic insert 28. Referring next to FIGS. 6, 7, and 8, components of an example target assembly are shown in an exploded view, demonstrating cap 30, spheres 26, as well as ceramic insert 28 and core 32, for example. While geometries have been shown to include circular geometries, geometries including planar portions are contemplated as well, such as hexagonal geometries for example. Referring next to FIGS. 9A and 9B, a bundle 90 for insertion within a reactor assembly can include multiple target assemblies. In accordance with example implementations, bundle 90 can include a plurality of target assemblies. This cross-section view of bundle 90 is shown with the configuration of target assemblies arranged in concentric circles, with an inner circle 92 of individual target assemblies 91a, next level circle 94, and an outer circle 96. In accordance with example implementations, it can be desirable to place target assemblies containing the spherical target materials within the inner circle 92 as shown. Each of these target assemblies 91a may be configured as described herein, and may include spherical target material core 32 as well as liner 28 and ceramic material 26 between core 32 and liner 28. Liner 28 can be Tungsten or Tantalum, for example. In accordance with another example implementation and with reference to FIG. 9B, a target assembly 91b can be provided. Assembly 91b can include an outer layer 200 of Zircaloy for example, a liner 202 of tantalum or tungsten, for example, ceramic material 204 (graphite, for example), and spherical material 206 such as the Np or Am spheres of the present disclosure. In accordance with example implementations, at least one side view of an example bundle is shown in FIG. 10. Referring next to FIG. 11, in accordance with example implementations, the bundle can have target assemblies configured specifically axially in relation to one another. In the configuration shown in FIG. 11 as configuration 110, it can be seen that the ceramic material and spherical material contained therein can be arranged juxtaposed to one another axially. In this circumstance, the target assembly can be arranged in two portions, wherein the spheres are contained within an upper portion or lower portion. In accordance with example implementations, these lower portions can be juxtaposed to one another and with spherical material in an upper portion while spherical material is arranged in a lower portion in a target assembly that is next to it. These target assemblies and reactor assemblies can be irradiated to produce Pu-238. The duration of irradiation and position in the reactor may be selected to modify the neutron energy spectrum and total neutron influence on targets to control the percentage of Pu-238 produced. For example, an irradiation position and exposure time may be chosen to allow for 10% of the neptunium to transmute to plutonium. Following irradiation, targets may be discharged from the reactor and allowed to decay for a period of time to decrease radioactivity. Irradiated bundles are disassembled and spheres are removed for acid dissolution. Spheres are low-fired and have high surface area, facilitating dissolution. Dissolved targets are processed to recycle neptunium, purify plutonium, and separate fission products. Separated and purified plutonium may be used to for making heat sources, for example by sol-gel methods. Pu-238 heat sources have typically been produced by powder-processing methods that require precipitation, ball-milling, and granule formation by slugging and screening. For example, the current process for producing Pu-238 heat source pellets is a multi-step process. First, dissolved 238Pu(III) nitrate is reverse strike precipitated using oxalic acid. The plutonium oxalate precipitate is then filtered and calcined to an oxide. Particle morphologies at this point include rosette and lathe-shaped particles, the latter of which cannot be used to press pellets and results in excessive shrinkage of pellets and cracking. Pu-238 oxide powders are ball milled to normalize the particle morphology and then hydraulically pressed into green pellets. Pellets are slugged through screens to obtain desirable particle sizes and then pre-sintered to adjust the ceramic activity. Thermally seasoned granules are then blended and loaded into a hot press die and hot pressed into a pellet. Pu-238 oxide pellets are substoichiometric in oxygen following hot pressing and are sintered in an oxygen-16 environment to re-oxidize. In contrast, Pu-238 spheres can be obtained by mixing chilled solutions of Pu-238 nitrate with hexamethylenetetramine and urea and forming droplets of the desired size in a heated, immiscible phase. Gelled microspheres are washed to remove impurities, including a hydrothermal water treatment. A hydrothermal treatment removes impurities and increases the specific surface area of the dried oxide microspheres. After washing, spheres are air-dried and calcined to remove moisture. Production of spheres and/or use of same can prevent dust generation, reduce the number of processing steps, and/or facilitate production of higher quality pellets. In compliance with the statute, embodiments of the invention have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the entire invention is not limited to the specific features and/or embodiments shown and/or described, since the disclosed embodiments comprise forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
	description	The present application claims priority from Japanese Patent application serial Nos. 2013-130070 and 2013-179670, each filed on Jun. 21, 2013, and Aug. 30, 2013, the contents of which are hereby incorporated by reference into this application. 1. Field of the Invention The present invention relates to radioactive organic waste treatment methods and systems. Specifically, it relates to methods and systems suitable for treating a radioactive organic waste such as a spent ion exchange resin and filter sludge which contain radionuclides, the radioactive organic waste being generated in nuclear power plants. 2. Description of Related Art Reactor water cleanup systems and fuel pool cooling cleanup systems of nuclear power plants generate a radioactive organic waste such as filter sludge including a cellulosic filter aid and anion exchange resin. Such radioactive organic waste is hereinafter also referred to as “radioactive spent resin” or simply referred to as “spent resin” or “organic waste”. The radioactive organic waste is stored in a storage tank over a long period of time. The radioactive organic waste is generated steadily with the operation of a nuclear power plant. And the radioactive organic waste is due to be subjected to treatments such as stabilization and volume reduction and to be ultimately disposed of by burial in the ground after the storage. The ion exchange resins include styrene-divinylbenzene as a base material, are chemically stable, and can be stored safely over a long period of time. The ion exchange resins, however, are hardly decomposable due to their stability and generally require a thermal treatment at a high temperature in order to reduce their volume. Exemplary methods for treating a radioactive spent ion exchange resin by a thermal decomposition (thermal treatment) can be found as a treatment method using plasma in Japanese Unexamined Patent Application Publication No. 2001-305287 (Patent Document 1); and as a treatment method using microwaves in Japanese Unexamined Patent Application Publication No. Sho 59-46899 (Patent Document 2). The treatment methods in Patent Document 1 and Patent Document 2 respectively promote volume reduction of the spent ion exchange resin. To solve the problem, there proposed are treatment methods for the volume reduction of the radioactive spent ion exchange resin by another technique than thermal decomposition. Examples of them are as follows. There are treatment methods of decomposing organic substances in the spent ion exchange resin with hydrogen peroxide. Typically, Japanese Unexamined Patent Application Publication No. Sho 61-270700 (Patent Document 3) describes a radioactive waste treatment method, in which the cellulosic filter sludge is hydrolyzed and liquefied with a cellulolytic enzyme to give a liquid, and the liquid is acted upon by hydrogen peroxide in the presence of an iron ion to oxidize and decompose the organic substances. Ferrous sulfate is used to give the iron ion in the working examples of this document. Japanese Unexamined Patent Application Publication No. Sho 58-161898 (Patent Document 4) discloses a method of bringing a radioactive spent ion exchange resin into contact with hydrogen peroxide in a ferric sulfate aqueous solution and whereby oxidizing and decomposing the ion exchange resin. Japanese Unexamined Patent Application Publication No. Sho 63-40900 (Patent Document 5) describes a treatment method of the radioactive spent ion exchange resin. By the treatment method, radionuclides contained in a spent ion exchange resin are eluted with a sulfuric acid aqueous solution to remove most of the radioactive substances (radionuclides) from the spent ion exchange resin; the spent ion exchange resin is then converted into an inorganic substance and solidified by an incineration or a chemical decomposition; an eluate containing the radionuclides is incorporated with a divalent iron ion and a base to form ferrite particles; and the radionuclides are taken into the formed ferrite particles and thus separated from the eluate. Japanese Unexamined Patent Application Publication No. Sho 63-188796 (Patent Document 6) describes a treatment method of a decontamination waste liquid. In the treatment method, a radioactive decontamination waste liquid is treated with a cation exchange resin, and whereby iron and radionuclides in the decontamination waste liquid are scavenged by the cation exchange resin and removed from the waste liquid. The decontamination waste liquid from which the radionuclides have been removed is solidified with cement in a metal drum. Independently, the iron and radionuclides scavenged by the cation exchange resin are eluted out with an organic acid (e.g., oxalic acid or formic acid) to give an eluate containing the eluted iron and radionuclides; and the eluate is given a liquid which converts the iron and radionuclides each into an oxide or hydroxide to be oxidized and decomposed. The oxide or hydroxide is separated from the eluate by a precipitation, and the separated oxide or hydroxide is stored for a radioactive decay. The eluate after the removal of iron and radionuclides becomes a clear water and reused in the nuclear power plant. Japanese Unexamined Patent Application Publication No. Sho 57-9885 (Patent Document 7) discloses a composition for removing a metal oxide using oxalic acid and hydrazine. The technology is disclosed as not a volume reduction treatment technology, but a chemical cleaning technology relating to such volume reduction treatment. Japanese Unexamined Patent Application Publication No. 2013-44588 (Patent Document 8) describes a treatment method for a spent resin in a nuclear power plant. The method is described as a treatment method for the volume reduction of filter sludge including a spent ion exchange resin and/or a filter aid. In the method, adsorbed radioactive metal ions are eluted out from the ion exchange resin by an action of oxalic acid (a kind of organic acids); and radionuclides included in crud including an iron oxide are dissolved and removed together with the crud, the crud being deposited on the resin surface. The organic acid (oxalic acid) for use in the treatment is decomposable typically by an oxidizing agent, and this enables the volume reduction of a waste liquid generated as a secondary waste. The present invention provides a method for treating a radioactive organic waste, the radioactive organic waste including a cation exchange resin adsorbing radionuclide ions, the method including the step of bringing the radioactive organic waste into contact with an organic acid salt aqueous solution containing an organic acid salt and whereby desorbing the radionuclide ions from the cation exchange resin, in which the organic acid salt contained in the organic acid salt aqueous solution includes a cation that is more readily adsorbable by the cation exchange resin than hydrogen ion is. This enables reduction in concentration of a radioactive substance in the radioactive organic waste and reduction in amount of a high-dose radioactive waste. Disadvantages in known technologies to be improved are as follows. The thermal decomposition treatment method in Patent Document 1 promotes the volume reduction of the spent resin. The method is, however, applied to such spent ion exchange resin containing radionuclides in a relatively high concentration. A high temperature treatment is required in order to decompose the spent resin which is chemically stable. For example, the high temperature treatment is a thermal treatment at 500° C. or high. This requires a remote control system typically for pressure reduction and atmosphere control, requires a sophisticated exhaust gas treatment system, and causes a treatment system for use in the method to have a complicated structure as a whole. The decomposition treatment method in Patent Document 2 using hydrogen peroxide can employ a simple system, but gives a residual waste liquid containing a large amount of sulfate group as a result of the treatment. Hence, the method requires a neutralization treatment. Therefore, the volume reduction performance of the method is lower than the thermal treatment method using the plasma. The volume reduction treatment by decomposition with hydrogen peroxide as in Patent Document 3 and Patent Document 4 gives a residual radioactive waste liquid containing a large amount of sulfate group derived from the exchange group of the ion exchange resin. Hence, the method requires the neutralization treatment. Therefore, the volume reduction performance of the radioactive waste by the method is lower than the thermal treatment method. The spent ion exchange resin treatment method in Patent Document 5 employs an aqueous sulfuric acid solution as a desirable eluent for eluting radionuclides from the spent ion exchange resin. The method therefore disadvantageously suffers from the formation of a large amount of waste sulfuric acid. This requires a treatment such as collection and reuse of sulfuric acid typically by electrodialysis. When iron and radionuclides adsorbed by a cation exchange resin are eluted out using an organic acid (e.g., oxalic acid or formic acid) as in the decontamination waste liquid treatment method in Patent Document 6, the radionuclides are insufficiently desorbed from the cation exchange resin and remain partially in the cation exchange resin. This has been experimentally verified by the present inventors. The composition for the removal of the metal oxide in Patent Document 7 is adapted to be used not in the volume reduction treatment of the spent resin, but in the cleaning of a metal material. The nuclear-power-plant spent resin treatment method using oxalic acid alone as described in Patent Document 8 requires a large amount of an oxalic acid solution because the method performs crud dissolution and elusion of adsorbed radioactive metal ions from the resin concurrently. An object of the present invention is to reduce a concentration of a radioactive substance in a radioactive organic waste and to reduce an amount of a high-dose radioactive waste. Embodiments of the present invention will be illustrated below. Initially, First Embodiment will be illustrated with reference to FIGS. 1 and 2. FIG. 1 illustrates the structure of a radioactive organic waste treatment system according to First Embodiment. A radioactive organic waste treatment system 1 according to the present embodiment has a first cleaning tank 3, a second cleaning tank 4, an organic acid tank 5, a transfer water tank 6, an organic acid salt tank 7, a transfer water tank 8, and a cleaning waste liquid treatment tank 9. The first cleaning tank 3 includes an agitating equipment that includes agitator blades 14 and a motor 15. The agitator blades 14 and the motor 15 are connected with a rotating shaft. An organic waste supply pipe 12 equipped with a transfer pump 13 is connected between a high-dose resin storage tank 2 and the first cleaning tank 3. An organic acid supply pipe 16 is connected between a bottom of the organic acid tank 5 and a selector valve 18; whereas a transfer water supply pipe 17 is connected between the bottom of the transfer water tank 6 and the selector valve 18. The organic acid tank 5 is charged with an oxalic acid aqueous solution; whereas the transfer water tank 6 is filled with water acting as transfer water. A liquid supply pipe 20 is connected between the selector valve 18 and the first cleaning tank 3 and is equipped with a transfer pump 19. The second cleaning tank 4 includes agitating equipment that includes agitator blades 23 and a motor 24. The agitator blades 23 and the motor 24 are connected with a rotating shaft. An organic waste transfer pipe 22 equipped with a transfer pump 21 is connected between the first cleaning tank 3 and the second cleaning tank 4. An organic acid salt supply pipe 25 is connected between the bottom of the organic acid salt tank 7 and a selector valve 27; whereas a transfer water supply pipe 26 is connected between the bottom of the transfer water tank 8 and the selector valve 27. The organic acid tank 5 is filled with an ammonium formate aqueous solution; whereas the transfer water tank 8 is filled with water acting as transfer water. A liquid supply pipe 29 is connected between the selector valve 27 and the second cleaning tank 4 and is equipped with a transfer pump 28. An organic waste transfer pipe 31 is inserted into the second cleaning tank 4 and one end of the organic waste transfer pipe 31 extends to the vicinity of the bottom of the second cleaning tank 4. The organic waste transfer pipe 31 is equipped with a transfer pump 30. An ozone injection pipe 37 having a multiplicity of nozzles is arranged at the bottom in the cleaning waste liquid treatment tank 9. The ozone injection pipe 37 is connected via an ozone supply pipe 38 to an ozone supplier 36. A waste liquid transfer pipe 33 is mounted into the first cleaning tank 3 and is connected to the cleaning waste liquid treatment tank 9. The waste liquid transfer pipe 33 is equipped with a transfer pump 32. A waste liquid transfer pipe 35 is mounted into the second cleaning tank 4 and is connected to the cleaning waste liquid treatment tank 9. The waste liquid transfer pipe 35 is equipped with a transfer pump 34. A gas exhaust pipe 39 is connected to the cleaning waste liquid treatment tank 9. A waste liquid discharge pipe 41 is equipped with a transfer pump 40 and is mounted into the cleaning waste liquid treatment tank 9. A nuclear power plant generates a radioactive organic waste typically in a reactor water cleanup system and a fuel pool cooling cleanup system. The radioactive organic waste includes filter sludge including a cellulosic filter aid and an ion exchange resin. The radioactive organic waste is stored in the high-dose resin storage tank 2 over a long period of time. A transfer water tank 10 filled with water is connected via a transfer water supply pipe 11 to the high-dose resin storage tank 2. The radioactive organic waste stored in the high-dose resin storage tank 2 includes crud removed from cooling water typically in the reactor water cleanup system and the fuel pool cooling cleanup system. The crud includes radionuclides such as cobalt-60. The ion exchange resin stored in the high-dose resin storage tank 2 includes adsorbed ions of radionuclides such as cobalt-60, cesium-137, carbon-14 and chlorine-36. FIG. 2 illustrates a procedure of a radioactive organic waste treatment method according to the present embodiment using the radioactive organic waste treatment system 1 in FIG. 1. In the following explanation, reference signs indicated by numbers alone correspond to the reference signs in FIG. 1. Initially, a step of supplying the radioactive organic waste from the high-dose resin storage tank 2 to the first cleaning tank 3 will be illustrated. The step is performed upstream from a first cleaning step S51 in FIG. 2. A boiling water nuclear power plant generates filter sludge (radioactive organic waste) including a cellulosic filter aid and an ion exchange resin typically from the reactor water cleanup system and fuel pool cooling cleanup system. The filter sludge is stored in the high-dose resin storage tank 2 over a long period of time. To treat the radioactive organic waste stored in the high-dose resin storage tank 2, the water in the transfer water tank 10 is supplied through the transfer water supply pipe 11 into the high-dose resin storage tank 2 to convert the radioactive organic waste in the high-dose resin storage tank 2 into slurry that is easily transferable. The transfer pump 13 is driven to supply the slurry containing the radioactive organic waste from the high-dose resin storage tank 2 through the organic waste supply pipe 12 to the first cleaning tank 3. The transfer pump 13 is stopped so as to stop the supply of slurry to the first cleaning tank 3 at the time when the level of the slurry containing the radioactive organic waste reaches a predetermined level in the first cleaning tank 3. The transfer pump 32 is then driven to supply water contained in the slurry from the first cleaning tank 3 through the waste liquid transfer pipe 33 into the cleaning waste liquid treatment tank 9. The water is handled as a waste liquid. The waste liquid brought into the cleaning waste liquid treatment tank 9 is treated in an after-mentioned cleaning waste liquid treatment step S52 as with a cleaning waste liquid. The transfer pump 40 is driven to bring the waste liquid through the waste liquid discharge pipe 41 to a storage tank. The transfer pump 32 is stopped upon the completion of transfer of water contained in the slurry in the first cleaning tank 3. The first cleaning step S51 (an organic acid treatment process) is performed thereafter. The first cleaning step S51 mainly performs the dissolution of crud such as iron oxide by injecting an organic acid. The crud has been transferred together with the radioactive organic waste to the first cleaning tank 3. The organic acid is used for reasons as follows. Such organic acid includes carbon, hydrogen, oxygen and nitrogen as main constitutive elements and does not give a non-volatile residue in a waste liquid when an organic acid aqueous solution generated as a cleaning waste liquid in the first cleaning step S51 is treated by oxidization with ozone (an organic acid oxidization treatment process). The organic acid for use herein is preferably at least one selected typically from formic acid, oxalic acid, carbonic acid, acetic acid, and citric acid. The organic acid tank 5 is filled with an aqueous solution of oxalic acid as the organic acid. The oxalic acid aqueous solution may be a saturated aqueous solution and may have an oxalic acid concentration of about 0.8 mol/L. The first cleaning step S51 performs operations as follows. The selector valve 18 is operated to allow the organic acid supply pipe 16 to communicate with the liquid supply pipe 20, and the transfer pump 19 is driven. The oxalic acid aqueous solution in the organic acid tank 5 is supplied through the organic acid supply pipe 16 and the liquid supply pipe 20 to the first cleaning tank 3. In this process, the water in the transfer water tank 6 is not supplied to the first cleaning tank 3 because the transfer water supply pipe 17 does not communicate with the liquid supply pipe 20. The transfer pump 19 is stopped so as to stop the supply of the oxalic acid aqueous solution to the first cleaning tank 3 at the time when the liquid level of the oxalic acid aqueous solution in the first cleaning tank 3 reaches a preset level. The oxalic acid aqueous solution may be supplied into the first cleaning tank 3 in an amount 10 times the amount of the radioactive organic waste in the first cleaning tank 3. A heater (not shown) is arranged on an outer surface of the first cleaning tank 3 and heats the oxalic acid aqueous solution in the first cleaning tank 3 to a temperature typically of 60° C. The temperature of the oxalic acid aqueous solution is held at 60° C. by controlling the thermal dose by the heater. While holding the temperature at 60° C., the motor 15 is driven to rotate the agitator blades 14 to thereby agitate the radioactive organic waste and the oxalic acid aqueous solution with each other in the first cleaning tank 3. The radioactive organic waste is immersed in the oxalic acid aqueous solution for duration typically of 6 hours with agitation in the first cleaning tank 3. Thus, the crud mixed with the radioactive organic waste is dissolved by the action of oxalic acid in the first cleaning tank 3. The crud dissolution allows the radionuclides such as cobalt-60 contained in the crud to migrate into the oxalic acid solution. An iron component in the crud, when dissolved, forms iron (II) ion. The iron (II) ion may react with oxalic acid to form iron oxalate, and the iron oxalate might precipitate. To suppress the formation of iron oxalate, a small amount of an oxidizing agent (e.g., hydrogen peroxide) that converts the iron(II) ion to iron(III) ion may be fed to the first cleaning tank 3 according to necessity. In the first cleaning step S51, the ion exchange resin forming part of the radioactive organic waste is immersed in oxalic acid as the organic acid. This allows part of the adsorbed radionuclides to be desorbed from the ion exchange resin. Specifically, oxalic acid dissociates into hydrogen ion and oxalic acid ion, and radionuclides adsorbed by a cation exchange resin and an anion exchange resin undergo ion exchange with the hydrogen ion and oxalic acid ion, respectively, and are desorbed from the ion exchange resins. The first cleaning step S51 is completed upon the lapse of 6 hours, i.e., the immersion time of the radioactive organic waste in the oxalic acid aqueous solution in the first cleaning tank 3. The motor 15 and the heating of the first cleaning tank 3 by the heater are respectively stopped, and the transfer pump 32 is driven to supply, as a cleaning waste liquid, the oxalic acid aqueous solution containing the radionuclides from the first cleaning tank 3 through the waste liquid transfer pipe 33 into the cleaning waste liquid treatment tank 9. The transfer pump 32 is stopped upon the completion of the transfer of the oxalic acid aqueous solution from the first cleaning tank 3 to the cleaning waste liquid treatment tank 9. A cleaning waste liquid treatment step S52 is performed after the completion of the transfer of the oxalic acid aqueous solution to the cleaning waste liquid treatment tank 9. In the cleaning waste liquid treatment step S52, ozone is supplied from the ozone supplier 36 through the ozone supply pipe 38 to the ozone injection pipe 37 for a predetermined time and is injected through the multiplicity of nozzles formed in the ozone injection pipe 37 into the oxalic acid aqueous solution in the cleaning waste liquid treatment tank 9. Oxalic acid contained as an organic component in the oxalic acid aqueous solution is decomposed by the injected ozone. The oxalic acid reacts with ozone and is decomposed into carbon dioxide and water. The carbon dioxide and the remainder of ozone injected into the cleaning waste liquid treatment tank 9 are supplied through the gas exhaust pipe 39 to an off-gas treatment equipment (not shown), and a radioactive gas contained in the gas discharged to the gas exhaust pipe 39 is removed by the off-gas treatment equipment. After the stop of ozone supply, the transfer pump 40 is driven to discharge the radionuclide-containing waste liquid in the cleaning waste liquid treatment tank 9 to the waste liquid discharge pipe 41 and is temporarily stored in a storage tank (not shown). A concentration-powdering step S54 as follows is then performed. The waste liquid in the storage tank is powdered typically with a thin film dryer, housed in a metal drum, and solidified with cement. Such radioactive solidified article is handled as a high-dose waste and is stored in a predetermined storage area. The radioactive waste liquid discharged from the cleaning waste liquid treatment tank 9 may be concentrated by heating, thus reduced in volume, charged into a metal drum, and solidified with cement. After the completion of the discharge of the oxalic acid aqueous solution from the first cleaning tank 3 to the cleaning waste liquid treatment tank 9, the selector valve 18 is operated to allow the transfer water supply pipe 17 to communicate with the liquid supply pipe 20; and the transfer pump 19 is driven to supply, as transfer water, water in the transfer water tank 8 through the transfer water supply pipe 17 and the liquid supply pipe 20 to the first cleaning tank 3. In this process, the oxalic acid aqueous solution in the organic acid tank 5 is not supplied to the first cleaning tank 3 because the organic acid supply pipe 16 does not communicate with the liquid supply pipe 20. The transfer pump 19 is stopped so as to stop the water supply to the first cleaning tank 3 at the time when a predetermined amount of water is supplied from the transfer water tank 8 to the first cleaning tank 3, and the water level in the first cleaning tank 3 reaches a preset level. The motor 15 is driven to rotate the agitator blades 14 to thereby agitate the radioactive organic waste and the water with each other in the first cleaning tank 3. Thus, the radioactive organic waste is converted into slurry. The transfer pump 21 is driven to supply the slurry containing the radioactive organic waste from the first cleaning tank 3 through the organic waste transfer pipe 22 to the second cleaning tank 4. When the slurry containing the radioactive organic waste is transferred from the first cleaning tank 3, the water amount in the first cleaning tank 3 reduces, and this may impede the transfer of the radioactive organic waste from the first cleaning tank 3. In this case, the transfer pump 19 may be driven according to necessity so as to supply water from the transfer water tank 8 into the first cleaning tank 3. The transfer pump 21 is stopped and the transfer pump 34 is driven upon the completion of the transfer of the radioactive organic waste from the first cleaning tank 3 to the second cleaning tank 4. The water in the second cleaning tank 4 is then discharged through the waste liquid transfer pipe 35 to the cleaning waste liquid treatment tank 9. The water brought from the second cleaning tank 4 to the cleaning waste liquid treatment tank 9 is treated in the cleaning waste liquid treatment step S52 as with the cleaning waste liquid. The transfer pump 40 is then driven to bring the treated water through the waste liquid discharge pipe 41 to a storage tank. A second cleaning step S53 (an organic acid salt treatment process) is performed when the transfer pump 34 is stopped so as to complete the water discharge from the second cleaning tank 4 to the cleaning waste liquid treatment tank 9. The second cleaning step S53 employs an organic acid salt to more efficiently desorb radionuclides adsorbed by the ion exchange resin (e.g., a cation exchange resin). The organic acid salt for use in the second cleaning step S53 is desirably one capable of dissociating in an aqueous solution to form a cation that is more readily adsorbable by a cation exchange resin than the hydrogen ion is. Specifically, the organic acid salt is preferably such an organic acid salt that includes carbon, hydrogen, oxygen, and nitrogen as main constitutive elements and does not form a non-volatile residue in a waste liquid when the organic acid salt aqueous solution as a cleaning waste liquid after the completion of the second cleaning step S53 is treated by oxidation typically with ozone (an organic acid salt oxidization treatment process). The organic acid salt is preferably a salt of an organic acid, where the salt is selected typically from ammonium salt, barium salt, and cesium salt; and the organic acid is selected typically from formic acid, oxalic acid, carbonic acid, acetic acid, and citric acid. The ammonium salt is decomposed into nitrogen gas and water by the oxidization treatment and can contribute to reduction in amount of radioactive waste more than barium salt and cesium salt do. The ammonium salt, barium salt, or cesium salt of formic acid, oxalic acid, carbonic acid, acetic acid, or citric acid dissociates in the aqueous solution into NH4+, Ba2+, or Cs+, respectively. The cations NH4+, Ba2+, and Cs+ are more readily adsorbable by the cation exchange resin than hydrogen ion is. The organic acid salt tank 7 is filled with an aqueous solution of ammonium formate as the organic acid salt. The ammonium formate aqueous solution may have an ammonium formate concentration of 1.2 mol/L. The second cleaning step S53 performs operations as follows. The selector valve 27 is operated to allow the organic acid salt supply pipe 25 to communicate with the liquid supply pipe 29; and the transfer pump 28 is driven. The ammonium formate aqueous solution is thus supplied from the organic acid salt tank 7 through the organic acid salt supply pipe 25 and the liquid supply pipe 29 to the second cleaning tank 4. In this process, the water in the transfer water tank 8 is not supplied to the second cleaning tank 4 because the transfer water supply pipe 26 does not communicate with the liquid supply pipe 29. The transfer pump 28 is stopped so as to stop the supply of the ammonium formate aqueous solution to the second cleaning tank 4 at the time when the liquid level of the ammonium formate aqueous solution in the second cleaning tank 4 reaches a preset level. A heater (not shown) is arranged on an outer surface of the second cleaning tank 4 and heats the ammonium formate aqueous solution in the second cleaning tank 4 to a temperature typically of 60° C. The temperature of the ammonium formate aqueous solution is held at 60° C. by controlling the thermal dose applied by the heater. While holding the temperature at 60° C., the motor 24 is driven to rotate the agitator blades 23 to thereby agitate the radioactive organic waste and the ammonium formate aqueous solution with each other in the second cleaning tank 4. While being agitated, the radioactive organic waste is immersed in the ammonium formate aqueous solution in the second cleaning tank 4 for duration typically of 2 hours. The radioactive organic waste includes a cation exchange resin adsorbing radionuclide ions. The adsorbed radionuclide ions are exchanged with ammonium ion and efficiently desorbed into the ammonium formate aqueous solution in the second cleaning tank 4, where the ammonium ion is present in the ammonium formate aqueous solution and is more readily adsorbable by the cation exchange resin than hydrogen ion is. This remarkably reduces the amount of radionuclides adsorbed by the cation exchange resin. The second cleaning step S53 is completed upon the lapse of the immersion time, i.e., 2 hours, of the radioactive organic waste in the ammonium formate aqueous solution in the second cleaning tank 4. The motor 24 and the heating of the second cleaning tank 4 by the heater are respectively stopped, the transfer pump 34 is driven to supply, as a cleaning waste liquid, the ammonium formate aqueous solution containing radionuclides from the second cleaning tank 4 through the waste liquid transfer pipe 35 into the cleaning waste liquid treatment tank 9. The transfer pump 34 is stopped upon the completion of the transfer of the ammonium formate aqueous solution from the second cleaning tank 4 to the cleaning waste liquid treatment tank 9. The cleaning waste liquid treatment step S52 is performed after the completion of the transfer of the ammonium formate aqueous solution to the cleaning waste liquid treatment tank 9. In the cleaning waste liquid treatment step S52, ozone is supplied by the ozone supplier 36 to the ozone injection pipe 37 for a predetermined time and is injected into the ammonium formate aqueous solution in the cleaning waste liquid treatment tank 9. Thus, ammonium formate contained as an organic component in the ammonium formate aqueous solution is decomposed by ozone. The ammonium formate reacts with ozone and is decomposed into carbon dioxide (gas), nitrogen gas, and water. Such gases are supplied through the gas exhaust pipe 39 to the off-gas treatment equipment (not shown). After the stop of ozone supply, the transfer pump 40 is driven to discharge the waste liquid containing radionuclides from the cleaning waste liquid treatment tank 9 to the waste liquid discharge pipe 41. The radionuclide-containing waste liquid is then temporarily stored in a storage tank (not shown). The concentration-powdering step S54 is then performed, and the waste liquid in the storage tank is powdered typically with a thin film dryer, housed in a metal drum, and solidified with cement. The resulting radioactive solidified article is also handled as a high-dose waste and stored in a predetermined storage area. After ammonium formate is decomposed by ozone in the cleaning waste liquid treatment tank 9, a radioactive waste liquid is discharged from the cleaning waste liquid treatment tank 9. The radioactive waste liquid may be concentrated by heating and reduced in volume, and then charged into a metal drum and solidified with cement. After the completion of the transfer of the ammonium formate aqueous solution to the cleaning waste liquid treatment tank 9, the selector valve 27 is operated to allow the transfer water supply pipe 26 to communicate with the liquid supply pipe 29; and the transfer pump 28 is driven to supply water from the transfer water tank 8 to the second cleaning tank 4. The transfer pump 28 is stopped so as to stop the water supply from the transfer water tank 8 to the second cleaning tank 4 after a predetermined amount of water is supplied to the second cleaning tank 4. The agitator blades 23 are rotated to agitate the radioactive organic waste and the water with each other in the second cleaning tank 4 to thereby form slurry containing the radioactive organic waste. The transfer pump 30 is driven to discharge the slurry containing the radioactive organic waste after cleaning from the second cleaning tank 4 to the organic waste transfer pipe 31. The radioactive organic waste after cleaning and being discharged to the organic waste transfer pipe 31 includes substantially no crud, contains radionuclide ions adsorbed by the cation exchange resin in a still reduced amount, and thereby has a remarkably lower radiation dose rate. The radioactive organic waste discharged to the organic waste transfer pipe 31 is temporarily stored in a storage tank (not shown). The radioactive organic waste taken out from the storage tank is incinerated typically in an incinerator. Ash formed by incineration is solidified with cement in a metal drum. The resulting solidified article is handled as a low-level radioactive waste. In the present embodiment, the first cleaning step S51 may employ one selected from formic acid, carbonic acid, acetic acid, and citric acid instead of oxalic acid; whereas the second cleaning step S53 may employ an ammonium salt, barium salt, or cesium salt of one selected from oxalic acid, carbonic acid, acetic acid, and citric acid; or barium salt or cesium salt of formic acid, instead of ammonium formate. The present embodiment enables reduction in amount of a high-dose radioactive waste and reduction in concentration of a radioactive substance contained in a radioactive organic waste. This is because the first cleaning step S51 employs the oxalic acid aqueous solution and thereby enables the dissolution of an iron oxide component mixed with the radioactive organic waste; and the second cleaning step S53 exchanges adsorbed radionuclide ions in the cation exchange range with ammonium ion contained in the ammonium formate aqueous solution, where the cation exchange resin is present as the radioactive organic waste. Even after the treatment with the oxalic acid aqueous solution, some radionuclide ions may be not desorbed from, but still adsorbed by the cation exchange resin. Particularly in this case, the present embodiment can efficiently desorb the residual adsorbed radionuclide ions from the cation exchange resin by bringing the ammonium formate aqueous solution into contact with the radioactive organic waste. Specifically, the present embodiment utilizes the action of an organic acid salt aqueous solution such as the ammonium formate aqueous solution and can desorb a larger amount of adsorbed radionuclide ions from the cation exchange resin than that of the method in Patent Document 6 in which adsorbed radionuclide ions are desorbed from the cation exchange resin by the organic acid aqueous solution (e.g., the oxalic acid aqueous solution). The present embodiment can still reduce the concentration of a radioactive substance contained in the radioactive organic waste such as the cation exchange resin and can reduce the amount of a high-dose radioactive waste (amount of the cation exchange resin adsorbing radionuclide ions). In addition, the present embodiment employs the oxidization treatment to decompose organic components in the cleaning waste liquid and performs concentration or dry powdering of the residual waste liquid. The organic components are oxalic acid contained in the oxalic acid aqueous solution; and ammonium formate contained in the ammonium formate aqueous solution. Thus, the embodiment can still further reduce the amount of the high-dose radioactive waste. In an embodiment of the radioactive organic waste treatment system 1, the liquid supply pipe 29 and the organic waste transfer pipe 31 may be connected to the first cleaning tank 3 without employing the second cleaning tank 4, the transfer pumps 21 and 34, and the organic waste transfer pipes 22 and 35. When the radioactive organic waste treatment system 1 having the structure according to this embodiment is employed, the first cleaning step S51 and the second cleaning step S53 can be performed by supplying the radioactive organic waste from the high-dose resin storage tank 2 into the first cleaning tank 3; and then supplying the oxalic acid aqueous solution and the ammonium formate aqueous solution sequentially to the first cleaning tank 3. The radioactive organic waste treatment system can undergo size reduction because of not using the second cleaning tank 4, the transfer pumps 21 and 34, and the organic waste transfer pipes 22 and 35. In addition, the system can perform the radioactive organic waste treatment in a shorter time because the system eliminates the need of transferring the radioactive organic waste from the first cleaning tank 3 to the second cleaning tank 4. A radioactive organic waste treatment method according to Second Embodiment will be illustrated below as another preferred embodiment of the present invention. The radioactive organic waste treatment method according to the present embodiment may be adapted to the treatment of a radioactive organic waste generated in a boiling water nuclear power plant. FIG. 3 illustrates a radioactive organic waste treatment system for use in the present embodiment. The radioactive organic waste treatment system 1A in FIG. 3 corresponds to the radioactive organic waste treatment system 1 in FIG. 1, except for not using the second cleaning tank 4, the transfer pumps 21 and 34, and the organic waste transfer pipes 22 and 35; arranging a cleaning tank 3A instead of the first cleaning tank 3 in FIG. 1; and arranging an aqueous ammonia supply tank 42 instead of the organic acid salt tank 7 in FIG. 1. The aqueous ammonia supply tank 42 is filled with aqueous ammonia as a basic aqueous solution. How the radioactive organic waste treatment system 1A differs from the radioactive organic waste treatment system 1 in FIG. 1 will be specifically described below. An organic acid supply pipe 16 is connected to the bottom of the organic acid tank 5. A transfer water supply pipe 17 is connected to the bottom of the transfer water tank 6. An aqueous ammonia supply pipe 45 is connected to the bottom of aqueous ammonia supply tank 42. The pipes 16, 17, and 45 are connected to a liquid supply pipe 20 that is in turn connected to the cleaning tank 3A. The pipes 16, 17, and 45 are equipped with on-off valves 43, 44, and 46, respectively. An organic waste transfer pipe 31 is connected to the cleaning tank 3A. The other structure (configuration) of the radioactive organic waste treatment system 1A is the same as with the radioactive organic waste treatment system 1 in FIG. 1. The radioactive organic waste treatment method according to the present embodiment using the radioactive organic waste treatment system 1A will be illustrated below. According to the present embodiment, the first cleaning step S51 and the second cleaning step S53 are performed in the cleaning tank 3A. A radioactive organic waste as slurry is supplied from the high-dose resin storage tank 2 through the organic waste supply pipe 12 to the cleaning tank 3A. The transfer pump 32 is driven to discharge water in the cleaning tank 3A though the waste liquid transfer pipe 33 to the cleaning waste liquid treatment tank 9, as in First Embodiment. After the discharge of the water from the cleaning tank 3A, the transfer pump 32 is stopped, the on-off valve 43 is opened, and the transfer pump 19 is driven to supply the oxalic acid aqueous solution from the organic acid tank 5 into the cleaning tank 3A. After the supply of a predetermined amount of the oxalic acid aqueous solution to the cleaning tank 3A, the on-off valve 43 is closed and the transfer pump 19 is stopped so as to stop the supply of the oxalic acid aqueous solution to the cleaning tank 3A. The agitator blades 14 are rotated to start agitation of the oxalic acid aqueous solution and the radioactive organic waste with each other in the cleaning tank 3A; the oxalic acid aqueous solution is heated to 60° C.; and the first cleaning step S51 is started. The radioactive organic waste is immersed in the oxalic acid aqueous solution for 6 hours in the cleaning tank 3A, and thereby crud mixed with the radioactive organic waste is dissolved by the action of oxalic acid. In addition, some of adsorbed radionuclide ions are desorbed from the cation exchange resin. After the lapse of 6 hours, the on-off valve 46 is opened, and the transfer pump 19 is driven. The aqueous ammonia is supplied from the aqueous ammonia supply tank 42 through the liquid supply pipe 20 into the cleaning tank 3A. In the cleaning tank 3A, the oxalic acid aqueous solution is neutralized with the aqueous ammonia and thereby forms ammonium oxalate as an organic acid salt. This results in immersion of the radioactive organic waste in an ammonium oxalate aqueous solution in the cleaning tank 3A, and the second cleaning step S53 is thus started. The transfer pump 19 is stopped and the on-off valve 46 is closed after the supply of a predetermined amount of the aqueous ammonia to the cleaning tank 3A. A part of the radioactive organic waste is a cation exchange resin adsorbing radionuclide ions. The adsorbed radionuclide ions are exchanged with ammonium ion in the ammonium oxalate aqueous solution and desorbed into the ammonium oxalate aqueous solution, as in First Embodiment. The step of immersing the radioactive organic waste in the ammonium oxalate aqueous solution may be performed for 2 hours. The desorption of the adsorbed radionuclide ions from the cation exchange resin is continuously performed during the step, and the amount of the radionuclide ions adsorbed by the cation exchange resin is significantly reduced. The second cleaning step S53 is completed upon the completion of the immersion of the radioactive organic waste in the ammonium oxalate aqueous solution for 2 hours. At this time, the rotation of the agitator blades 14 is stopped, and the transfer pump 32 is driven to transfer the ammonium oxalate aqueous solution from the cleaning tank 3A to the cleaning waste liquid treatment tank 9. Ozone is supplied to the ammonium oxalate aqueous solution in the cleaning waste liquid treatment tank 9 to decompose ammonium oxalate into nitrogen gas, carbon dioxide gas, and water. After the completion of the cleaning waste liquid treatment step S52 by the ozone supply into the cleaning waste liquid treatment tank 9, a waste liquid is discharged from the cleaning waste liquid treatment tank 9 to the waste liquid discharge pipe 41 and temporarily stored in a storage tank (not shown). The waste liquid in the storage tank is powdered typically with a thin film dryer, housed in a metal drum, and solidified with cement. The present embodiment offers advantageous effects as given by First Embodiment. In addition, the radioactive organic waste treatment system 1A for use in the present embodiment can have a size smaller than that of the radioactive organic waste treatment system 1. This is because the system 1A does not require the second cleaning tank 4, the transfer pumps 21 and 34, and the organic waste transfer pipes 22 and 35. The present embodiment enables the treatment of the radioactive organic waste using the downsized radioactive organic waste treatment system 1A. The present embodiment can perform the radioactive organic waste treatment in a shorter time. This is because the present embodiment can perform the first cleaning step S51 and the second cleaning step S53 both in the cleaning tank 3A and, unlike First Embodiment, does not require the transfer of the radioactive organic waste from the first cleaning tank 3 to the second cleaning tank 4. In addition, the present embodiment can perform the radioactive organic waste treatment in a still shorter time. The reason is as follows. According to the present embodiment, aqueous ammonia is added to the oxalic acid aqueous solution in the cleaning tank 3A after the completion of the first cleaning step S51. The oxalic acid aqueous solution is thereby neutralized and forms an ammonium oxalate aqueous solution as an organic acid salt aqueous solution. This eliminates the need of the transfer of the oxalic acid aqueous solution acting as the organic acid aqueous solution from the cleaning tank 3A to the cleaning waste liquid treatment tank 9. This also eliminates the need of the cleaning waste liquid treatment step S52 for an oxalic acid aqueous solution in the cleaning waste liquid treatment tank 9. In another embodiment, a formic acid aqueous solution may be employed as the organic acid aqueous solution for use in the first cleaning step S51; and an ammonium formate aqueous solution may be employed as the organic acid salt aqueous solution for use in the second cleaning step S53. Even this embodiment can be performed as with the present embodiment. Specifically, after the completion of the first cleaning step S51, aqueous ammonia is added to the formic acid aqueous solution in the cleaning tank 3A in which the radioactive organic waste is immersed; and an ammonium formate aqueous solution is formed as the organic acid salt aqueous solution in the cleaning tank 3A as a result of formic acid neutralization. The second cleaning step S53 for the radioactive organic waste is performed using the ammonium formate aqueous solution in the cleaning tank 3A. According to the present embodiment, the organic acid for use in the first cleaning step S51 may correspond to (be identical to) the base component of the organic acid salt (formic acid ion moiety of formic acid, or oxalic acid ion moiety of oxalic acid) for use in the second cleaning step S53. In this case, the solid-liquid separation (separation of the radioactive organic waste from the organic acid aqueous solution) is not performed after the first cleaning step S51, but the organic acid in contact with the radioactive waste liquid is neutralized with a basic aqueous solution (e.g., aqueous ammonia) to form an organic acid salt aqueous solution, and the formed organic acid salt aqueous solution is used to clean the radioactive organic waste in the second cleaning step S53. As used herein the term “base component” refers to a Broensted base, namely, a component that receives hydrogen ion. A radioactive organic waste treatment method according to Third Embodiment will be illustrated below as still another preferred embodiment of the present invention. The radioactive organic waste treatment method according to the present embodiment may be adapted to the treatment of a radioactive organic waste generated in a pressurized water nuclear power plant. FIG. 4 illustrates a radioactive organic waste treatment system for use in the present embodiment. The radioactive organic waste generated in the pressurized water nuclear power plant does not include crud such as iron oxide, unlike the radioactive organic waste generated in the boiling water nuclear power plant. The treatment for the radioactive organic waste generated in the pressurized water nuclear power plant does not require the first cleaning step S51 for dissolving crud using an organic acid aqueous solution. The radioactive organic waste treatment system 1B is used for the radioactive organic waste treatment according to the present embodiment so as to treat the radioactive organic waste generated in the pressurized water nuclear power plant. As illustrated in FIG. 4, the system 1B corresponds to the radioactive organic waste treatment system 1 in FIG. 1, except for not employing the first cleaning tank 3, the organic acid tank 5, the transfer water tank 6, the transfer pumps 19, 21, and 32, the liquid supply pipe 20, and the organic waste transfer pipes 22 and 33; and except for connecting the second cleaning tank (hereinafter also simply referred to as “cleaning tank”) 4 to the organic waste supply pipe 12. The other configurations of the radioactive organic waste treatment system 1B are as with the radioactive organic waste treatment system 1 in FIG. 1. The radioactive organic waste generated in the pressurized water nuclear power plant is stored in the high-dose resin storage tank 2. The radioactive organic waste is supplied from the high-dose resin storage tank 2 through the organic waste supply pipe 12 to the cleaning tank 4 and undergoes the radioactive organic waste treatment method according to the present embodiment. The method according to the present embodiment subjects the radioactive organic waste not to the first cleaning step S51 as in First Embodiment, but to the second cleaning step S53; and subjects a waste liquid generated in the second cleaning step S53 to the cleaning waste liquid treatment step S52. Slurry containing the radioactive organic waste is supplied to the cleaning tank 4, and water in the cleaning tank 4 is discharged to the cleaning waste liquid treatment tank 9. An organic acid salt aqueous solution such as an ammonium formate aqueous solution is then supplied from the organic acid salt tank 7 into the cleaning tank 4. The radioactive organic waste in the cleaning tank 4 is immersed in the ammonium formate aqueous solution for 2 hours. The radioactive organic waste includes a cation exchange resin adsorbing radionuclide ions. The adsorbed radionuclide ions are exchanged with ammonium ion in the ammonium formate aqueous solution and thereby desorbed from the cation exchange resin into the ammonium formate aqueous solution. After the completion of the second decontamination step (second cleaning step) for 2 hours, the ammonium formate aqueous solution is discharged from the cleaning tank 4 to the cleaning waste liquid treatment tank 9. The cleaning waste liquid treatment step S52 is performed in the cleaning waste liquid treatment tank 9 by supplying ozone to the ammonium formate aqueous solution to decompose ammonium formate into nitrogen gas, carbon dioxide gas, and water. After the completion of the cleaning waste liquid treatment step S52, a radioactive waste liquid may be discharged from the cleaning waste liquid treatment tank 9, powdered typically with a thin film dryer, housed in a metal drum, and solidified with cement. The radioactive waste liquid may also be concentrated by heating, housed in a metal drum, and solidified with cement. The method according to the present embodiment treats the radioactive organic waste with an organic acid salt aqueous solution such as an ammonium formate aqueous solution. As in First Embodiment, the use of ammonium formate aqueous solution enables the desorption of adsorbed radionuclide ions from the cation exchange resin in a larger amount than that of the technique disclosed in Patent Document 6 where adsorbed radionuclide ions are desorbed from a cation exchange resin by the action of an organic acid aqueous solution (e.g., an oxalic acid aqueous solution). The method can still reduce the concentration of radionuclides in a radioactive organic waste typified by a cation exchange resin and can reduce the amount of a high-dose radioactive waste (amount of the cation exchange resin adsorbing radionuclide ions). Here, radionuclide ions adsorbed by an anion exchange resin can be removed by an oxalate ion contained in the oxalic acid aqueous solution. And the radionuclide ions can be removed by the formate ion contained in the ammonium formate aqueous solution. In addition, the method employs the oxidization treatment to decompose organic components in the cleaning waste liquid and employs the concentration or dry powdering of the residual waste liquid. The organic components are exemplified by oxalic acid contained in the oxalic acid aqueous solution; and ammonium formate contained in the ammonium formate aqueous solution. The method can thereby still reduce the amount of a high-dose radioactive waste. The radioactive organic waste treatment system 1B for use in the present embodiment can have a smaller size than that of the radioactive organic waste treatment system 1. This is because the system 1B does not require the facilities such as the first cleaning tank 3 and the organic acid tank 5 to be arranged in the radioactive organic waste treatment system 1, as described above. How to reduce the amount of a cleaning agent for use in chemical cleaning of an organic waste generated from nuclear facilities will be illustrated. FIG. 5 is a flow chart schematically illustrating a treatment method for an organic waste such as a spent ion exchange resin or filter sludge. The organic waste treatment method illustrated in FIG. 5 includes a first cleaning step S101, a second cleaning step S102, and a waste liquid decomposition step S103. The first cleaning step S101 decomposes crud with an aqueous solution of a reducing organic acid, where the crud is deposited on the organic waste. The second cleaning step S102 is performed after the step S101 and elutes adsorbed radioactive metal ions from the organic waste using an organic acid salt aqueous solution. The waste liquid decomposition step S103 decomposes organic substances by heat or an oxidizing agent such as hydrogen peroxide or ozone, where the organic substances are contained in a crud solution and a radionuclide eluate generated in the first cleaning step S101 and the second cleaning step S102, respectively. The first cleaning step S101 is performed in order to dissolve and remove radionuclides such as Co-60 (cobalt-60) together with the crud by the action of the reducing organic acid aqueous solution, where the radionuclides are incorporated in the crud deposited on the organic waste. In addition, the step is expected to advantageously elute part of adsorbed radioactive metal ions from the ion exchange resin. The second cleaning step S102 is performed in order to efficiently elute adsorbed radioactive metal ions from the organic waste with a solution of an organic acid salt. The organic acid salt for use herein is desirably one that forms an ion having ion selectivity for the organic waste higher than those of hydrogen ion and the organic acid ion; or forms an ion capable of forming a stable complex with a radioactive metal ion adsorbed by the organic waste. In an embodiment, a non-volatile ion may be added in an amount approximately corresponding to the ion exchange capacity of the ion exchange resin. This enables still efficient elution of the radioactive metal ions. Here, the ion having the ion selectivity for the organic waste higher than those of the hydrogen ion is typically hydrazine ion. The organic acid ion is typically oxalate ion. Further, the ion having the ion selectivity for the organic waste higher than those of the oxalate ion is formate ion or carbonate ion, for example. Furthermore, the ion capable of forming the stable complex is typically oxalate ion or citrate ion. The organic acid and organic acid salt for use in embodiments of the present invention preferably include at least one element selected typically from carbon, hydrogen, oxygen, nitrogen and do not give a non-volatile residue in a waste liquid after oxidization decomposition or thermal decomposition of the cleaning waste liquid. The organic acid is exemplified by oxalic acid and citric acid. The organic acid salt is exemplified by hydrazine salts of oxalic acid, citric acid, formic acid, carbonic acid, and acetic acid. The organic acid salt is preferably hydrazine oxalate or hydrazine citrate which includes an organic acid having reducibility. The non-volatile ion may be added to the organic acid salt in an amount corresponding approximately to the ion exchange capacity of the ion exchange resin. The non-volatile ion is added in an amount of less than 1% of the resin organic waste amount and may probably not substantially affect the volume reduction of the resulting waste. The non-volatile ion is exemplified by potassium ion, zinc ion, calcium ion, and cobalt ion. The second cleaning step S102 elutes the adsorbed radioactive metal ions from the organic waste by the action of the organic acid salt and thereafter gives a waste. The waste is subjected to incineration or solidification (S104). The waste liquid decomposition step S103 decomposes the organic substances in the crud solution and radionuclide eluate and thereafter gives a radionuclide solution. The radionuclide solution is subjected to volume reduction (S105), and the residue of which is charged into a container or solidified (S106). Here, the volume reduction (S105) is carried out by a concentration process or a dry powdering process. The treatment method according to the present embodiment basically includes the steps as mentioned above, but may be modified as follows. Initially, the first cleaning step S101 and the second cleaning step S102 may be performed step by step in an identical cleaning tank (facilities in the same block). The organic waste may be heated during the first cleaning step S101 and the second cleaning step S102. The solutions of the organic acid and organic acid salt may be supplied continuously or intermittently in the two steps during the immersion treatment of the organic waste in the solutions of the organic acid and organic acid salt, respectively. The first cleaning step S101 can be omitted when the organic waste includes substantially no crud such as iron oxide. The first cleaning step S101 can also be omitted when the second cleaning step S102 employs an organic acid salt capable of dissolving the crud. Independently, the second cleaning step S102 can be omitted when the first cleaning step S101 employs an organic acid capable of efficiently eluting adsorbed radioactive metal ions from the organic waste. The first cleaning step S101 and the second cleaning step S102 generate a crud solution and a radionuclide eluate, respectively. The crud solution and the radionuclide eluate may be subjected to the waste liquid decomposition step S103 in an identical tank (facilities of the same block) at different times or simultaneously. FIG. 6 illustrates an organic waste treatment system according to Fourth Embodiment. The treatment system in FIG. 6 includes a chemical cleaning unit 101 that treats an organic waste; and a waste liquid decomposing unit 102 that treats a cleaning waste liquid. A first cleaning step S101 and a second cleaning step S102 are performed in the chemical cleaning unit 101 (facilities of the same block). The first cleaning step S101 dissolves crud; whereas the second cleaning step S102 elutes radioactive metal ions from the organic waste. The chemical cleaning unit 101 includes a first receiver tank 202, a chemical reaction tank 204, and a cleaning liquid supply tank 206. The waste liquid decomposing unit 102 includes an ozone decomposition system 209, a treated water collection tank 210, a dry powdering system 211, and a solidification system 212. A chemical cleaning organic waste is stored in an organic waste storage tank 201. Slurry containing about 10 percent by weight of the organic waste is drawn from the organic waste storage tank 201 and transferred in a predetermined amount to the first receiver tank 202 in the chemical cleaning unit 101. The organic waste is then transferred by a transfer pump 221 to the chemical reaction tank 204. An oxalic acid aqueous solution is supplied in an amount of about 72 g/L from the cleaning liquid supply tank 206 to the transferred organic waste in the chemical reaction tank 204 by a transfer pump 222. Thus, the dissolution treatment of crud deposited on the organic waste is performed in the chemical reaction tank 204. Oxalic acid is used herein as an exemplary organic acid. The oxalic acid solution to be supplied from the cleaning liquid supply tank 206 to the chemical reaction tank 204 may be a saturated solution and have a concentration of about 0.8 mol/L. An aqueous citric acid solution may be used instead of the oxalic acid aqueous solution. The organic acids have reducibility. Temperature control equipment 205 is arranged so as to heat the chemical reaction tank 204. The heating may be performed to a temperature of lower than 100° C. In an embodiment, oxalic acid alone may be collected by precipitating a crud contained in a crud solution generated in the treatment and thereafter separating its supernatant liquid etc., and the collected oxalic acid may be transferred to the cleaning liquid supply tank 206 by a transfer pump 223 and reused in the crud dissolution. The ultimately generated crud solution is handled as a cleaning waste liquid and transferred to the ozone decomposition system 209 in the waste liquid decomposing unit 102. A hydrazine formate aqueous solution is continuously supplied in an amount of about 40 to about 400 g/L from the cleaning liquid supply tank 206 to the residual organic waste after crud dissolution in the chemical reaction tank 204. Thus, an elution treatment of adsorbed radioactive metal ions from the organic waste is performed. The hydrazine formate aqueous solution for use herein may be a neutral solution having a pH of about 7. Here, concentration of the hydrazine formate aqueous solution is a mass of its solute (the hydrazine formate) per 1 liter of the aqueous solution. The treatment generates a radionuclide eluate. In an embodiment, the hydrazine formate aqueous solution alone may be collected from the radionuclide eluate, and the collected hydrazine formate aqueous solution may be transferred to the cleaning liquid supply tank 206 and reused in the elution of radioactive metal ions. A hydrazine salt of oxalic acid, acetic acid, or citric acid may be used herein instead of hydrazine formate. The ultimately generated radionuclide eluate is handled as a cleaning waste liquid and transferred to the ozone decomposition system 209. When performed with respect to Co-60 adsorbed by the organic waste, the decontamination process (cleaning process) offers a decontamination performance in terms of decontamination factor DF of about 4 when employing oxalic acid as the cleaning agent; and offers better decontamination performance in terms of a DF of 20 or more when employing the hydrazine formate as the cleaning agent. It is necessary to add the oxalic acid many times in order to obtain the DF of 20 or more when employing only the oxalic acid as the cleaning agent. On the other hand, it is not necessary to add the hydrazine formate many times when employing the hydrazine formate as the cleaning agent. Thus, it is possible to decrease the amount used of the cleaning agent. As used herein the term “decontamination factor DF” refers to a numerical value as determined by dividing the counting rate before decontamination by the counting rate after decontamination. In addition, the decontamination process (an ion elution) employing the hydrazine formate is carried out after the decontamination process (a crud dissolution) employing oxalic acid. Thus, the ion elution is not carried out when employing oxalic acid as the cleaning agent. Therefore, the term “decontamination factor DF” refers to a numerical value as determined by dividing the counting rate before the decontamination by the counting rate after decontamination of only the crud dissolution. On the other hand, when the ion solute is carried out, the term “decontamination factor DF” refers to a numerical value as determined by dividing the counting rate before the decontamination by the counting rate after decontamination of the crud dissolution and the ion solute. The organic waste after the cleaning is drawn as slurry by weight from the chemical reaction tank 204 and transferred to a second receiver tank 207, where the slurry has an organic waste concentration of about 10 percent. The organic waste is transferred in a certain amount to an incineration system or cement solidification system 208 and is incinerated or solidified with cement. Oxalic acid and hydrazine formate contained in the cleaning waste liquid transferred to the ozone decomposition system 209 are decomposed typically into carbon dioxide, nitrogen, and water by ozone decomposition. This converts organic substances in the cleaning waste liquid into inorganic substances and allows solids components in the waste liquid to be crud, eluted radioactive metal ions, and other salts. A radionuclide solution formed by ozone decomposition is collected into the treated water collection tank 210, transferred in a certain amount to the condensation system or dry powdering system 211 by a pump 224, and is subjected to a concentration or dry powdering treatment. The resulting residue is transferred to the container filling system or solidification system 212 and stored as filled in the container. The residue may be solidified with cement or another solidification agent. FIG. 7 illustrates an organic waste treatment system according to Fifth Embodiment. The treatment system in FIG. 7 includes a chemical cleaning unit 103 that supplies a cleaning liquid containing a non-volatile ion to an organic waste; and a waste liquid decomposing unit 102 that treats a cleaning waste liquid. Using the treatment system, the first cleaning step S101 and the second cleaning step S102 are performed in the same block as in Fourth Embodiment. The organic waste is drawn as slurry from the organic waste storage tank 201, transferred to the first receiver tank 202, and transferred to the chemical reaction tank 204 by a pump 221. An oxalic acid solution is fed to the chemical reaction tank 204, followed by crud dissolution. The concentration and amount of the oxalic acid solution, and the temperature in the process are as in Fourth Embodiment. After the crud dissolution, cobalt (as ion) is fed from non-volatile ion supply tank 213 (non-volatile ion storage tank) and added to hydrazine formate for use in the elution of radioactive metal ions. The cobalt (ion) is added in an amount corresponding to about 3 meq/L of the ion exchange capacity of the organic waste to be treated. The resulting mixture is supplied as an eluent to the chemical reaction tank 204, followed by elution of radioactive metal ions. The eluent for use herein may be a neutral liquid having a pH of 7 and may be supplied in an amount as in Fourth Embodiment. The treatment method according to the present embodiment offers decontamination performance with respect to Co-60 in terms of a DF of 1000 or more, indicating significantly better decontamination performance than that in Fourth Embodiment. Equivalent or better decontamination performance can be obtained by using an aqueous solution containing potassium ion, zinc ion or calcium ion instead of cobalt ion (an aqueous solution of cobalt sulfate, cobalt nitrate or cobalt chloride) to be added to hydrazine formate. A cleaning waste liquid generated in the chemical cleaning unit 103 is transferred to the ozone decomposition system 209 and is treated as in Fourth Embodiment.
052788776	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference 10 shows an open trench in used soil S to disengage equipment at risk of radioactive contamination and that may be irradiating, said equipment consisting of straight extensions, such as pipes, sluices, sheathing, plumbing, electrical cables, etc. As a non-limiting example of off-line equipment to be dismantled, we have shown a section in FIG. 1 of two metal pipes 12 and a concrete sheathing 14 composed of one element 16 with a U-shaped section called a flue and a cover 18 formed from attached flooring (the inside of the sheathing 14 equipped with other pipes and plumbing is not shown). Above the trench 10, on supports 20 and 22, there is a movable vessel 24 seen from the side by its "front" face (i.e., the side facing the equipment to be dismantled). The vessel 24 is shaped like a rectangular parallelepiped around 13 meters long, 5 meters wide and 4 meters high. This vessel has a self-supporting structure built around a very resistant deck 26 composed of a group of steel beams (particularly beams 25 and 27, and U-beams 29 and 31, profile views in FIG. 1) capable of supporting both lifting and handling vehicles and also large loads of earth and/or debris from the equipment to be dismantled. The vessel 24 is moved and positioned by a moving crane (not shown) with a double set of slings in front and in back, each composed of upper slings 28 joined to the hook of the crane and kept apart by a rigid tubular control stick 30 and lower slings 32 located as illustrated in FIG. 1 between the control stick 30 and the deck 26, on each side of the vessel 24. Moreover, the roof 34 has two pairs of vertical protective units 36 whose V-shaped end grooves are designed to hold the control sticks 30 at rest and thus protect a roof 34. Considering the large loads to be supported, it is important to use heavy-duty vessel supports and to put them in place very carefully. As a non-limiting example, reference 22 shows a continuous concrete rail running the length of the pipes to be dismantled, and reference 20 shows a block composed of a concrete die 38 placed in the bottom of the trench or ditch 10 and a tubular steel pillar 40 whose height is adjustable. To calibrate the vessel 24 on its supports 20 and 22, wooden planks 42 are placed between the supports and the floor 26. FIG. 2 shows a schematic view of the top (roof removed) of the vessel 24 in the invention. Anchored on the deck 26, along each long side of the vessel are posts 44 (shown by the square sections) to define four modules 41, 43, 45 and 47 in the vessel. Moreover, each "front" and "back" side of the vessel has two twin propped posts 49 anchored on the deck 26. The posts 44 have boarding 46 that forms a rigid external envelope and the roof 34. As can be seen in FIG. 2, the blocks 20 are arranged to the right of the posts 44 to ensure good load transfer. Note that the use of the blocks is well suited for workplaces with difficult access and where the available space is limited. The deck 26 includes a wide extended central opening 48 whose shape is mostly rectangular at the height of the modules 43 and 45 whereby occupants of the vessel 24 have access to the pipes 12 and the concrete sheathing 14. To ensure good protection and insulation from the outside, the edges of the opening 48 support four skirts 50 made of plastic sheeting lined with a double layer of vinyl (see FIGS. 1 and 3). The four skirts 50 form a static confinement, a sort of protective curtain placed around the central opening 48 to surround and insulate the work area or work zone where the section is being dismantled from the outside. The vessel 24 is equipped with a locking chamber housed in the module 43. The locking chamber is the type with two compartments 52 and 54 made with vinyl walls mounted on tubes that permits input-output operations by operators through three doors shown schematically in FIG. 2 by three double arrows. The part of the roof opposite each module includes a high rectangular window 56 closed and sealed by a movable cover 58. The windows 56, mainly windows corresponding to the modules 41 and 47, are used to evacuate earth from the ditch and from special containers described in detail below. The entire interior of the boarding 46 is lined with a double thickness of vinyl sheeting (not shown) and ventilation in the vessel is provided by a powerful high-capacity filtering unit 60 (for example, 100 Nm.sup.3 /h) equipped with changeable filters suitably adapted to hold contaminated dust, inter alia. Of course, the vessel is equipped with a radio-controlled atmospheric air-sampling device. The vessel described here as a non-limiting example of an initial embodiment of the invention has an interesting feature from the standpoint of transport from one workplace to another; more specifically, the vessel is preassembled in three subunits, which are the roof 34 and two half-shells, each composed of half of the self-supporting structure with its external boarding 46. As can be seen in FIGS. 1 and 2, the two half-shells are assembled with bolts 62 for the posts 29 and 31 and the twin posts 49, on both sides of a vertical median plane P,P'. Thus, the half shells built around the two half-decks can easily be transported using a trailer. The inside arrangement of the vessel is shown in FIG. 2 and, partially, in FIG. 3, which details modules 41 and 43 in longitudinal section along line A,A',A",A"' in FIG. 2. The module 41 adjacent to the "front" side of the vessel houses a holding area for a container of steel or fiber-reinforced concrete 64 designed to take the contaminated soil and a holding area 66 for temporarily storing tools, for example, a double clam-shell bucket 68 shown in FIG. 3. The clam-shell bucket 68 is attached to a block and tackle 70 which is in turn attached to a rolling bridge 72 that can be moved on two rails 74 covering the whole inside of the vessel and supported by posts 44. The block and tackle 70 can be used in combination with the hydraulically closing clam-shell bucket 68 to clean the ditch of contaminated soil and/or to move large loads within the vessel, for example, the container 64 for the soil or pieces of the concrete sheathing 14 (in this case, the bucket 68 is placed temporarily over the area 66 composed of sheet steel whose edges are covered with a vinyl cover that can be changed). In its usual position shown in FIGS. 2 and 3, the container 64 for the soil is located under the mouth of a hopper 76 that passes through the "front" wall of the vessel. This hopper 76 whose outside entrance is controlled by a hydraulically controlled hood or helmet 78 makes it possible temporarily to store contaminated soil in the vessel dug up by the hydraulic scoop, which can move in different directions with extending arms 80 anchored on an outside face 82 of the deck 26 (in FIG. 2, only the movable base of the scoop is shown schematically as reference 80). The scoop 80 is equipped with a clam-shell bucket 84 whose two buckets are closed with a protective sheet and a hydraulic bucket guide device 85 for precision work; the operator works from a control panel 86 located beside a regular pressurized fluid generator unit 88. If we look again at FIG. 2, the modules 43 and 45 of the vessel are mainly occupied by the rectangular central opening 48, which, for reasons of volume gain, is shifted in relation to the symmetrical plane P,P'. However, one can see that the opening 48 is aligned on the equipment to be dismantled, i.e., the concrete sheathing 14 (of which only the cover 18 is visible in FIG. 2) and the steel pipes 12. The equipment is therefore directly accessible from inside the vessel. The module 43 houses the locking chamber with its compartments 52 and 54, while the module 45 houses a dismantling area 90 for large-sized pieces of equipment. As an example, FIG. 2 shows a specific element around 3 meters long (a flue 92) that goes with the concrete sheathing to be dismantled. This element goes with a specific section T1 being dismantled and shown by the dotted lines in FIG. 2. The temporary holding area 66 or the dismantling area 90 is composed of a sheet steel plate with the edges equipped with a vinyl sheeting that can be changed. For reasons of yield, the length of the opening 48 has been made slightly larger than two lengths of flue 92 to correspond to two specific sections to be dismantled T1 and T2. To conclude the description of the modules 43 and 45, a cart 94 suspended in the opening 48 is mounted on two rails composed of beams 96 on the deck 26 which define the two large sides of the opening 48. The cart 94 can take the container 64 for the soil 10 (as shown in 64a in FIGS. 2 and 3) during the ditch-cleaning phase and/or other debris at risk of contamination during the dismantling phase per se. Module 47 basically houses a standard high-security anti-radiation container 98 made of steel provided with an internal lining of concrete placed crosswise in relation to the vessel. This container 98 is designed to take debris from equipment after dismantling. In this case, the capacity of the container allows it to store the equivalent of four three-meter sections. Module 47 also houses an adjustable bracket crane 100 whose arm 102 carries an electrical block and tackle 104 which can itself carry a certain number of tools such as hooks, self-closing pliers, hydraulic pliers, saws, etc. . . . This bracket crane 100 is specially designed to manipulate pieces of the section being dismantled for loading the container 98, either directly or after being stored in the holding area 90. To conclude, the module 47 houses a second holding area (not shown) for temporary storage of tools, composed of a sheet-steel plate whose edges are equipped with vinyl sheeting that can be changed. As can be noted from the preceding description, the vessel is arranged so that the dismantling work can be carried out with good protection against radiation in a relatively small area. Moreover, the airspace above the equipment is largely used to dismantle and move the vessel 24 and for input-output operations of the soil-holding container 64 and the anti-radiation container 98 after release of the covers 58 of the two windows 56 corresponding to modules 41 and 47. The process in the invention using the vessel just described is implemented as follows: the vessel is started up by putting a series of five blocks 20 in the free space at 3-meter intervals and placing the supporting rail 22 on both sides of the path of the pipes 12 and the sheath 14 to be dismantled. As with all terracing and ditch work, the excavated earth is systematically monitored so it can be sorted according to the degree of radioactivity per unit of weight (measured, for example, in Becquerels/kg or Bq/kg). This monitoring is done by operators in protective clothing using portable counters that count the disintegration of any radioactive elements that may be present. Thus, a preliminary dig is done whose depth is determined either: by stopping around 10 cm above the flue boards; PA1 by exceeding a definite threshold (for example, 3700 Bq/kg) for mass activity of the soil released. The vessel 24 is then placed above the first sections to be dismantled, using a crane, then conveniently fixed on the blocks 20 and the rail 22. To complete insulation of the work area, the flexible vinyl curtain 50 is put in place, as well as two coffer dams in "front" and in "back" of the vessel to collect rainwater. Only water recovered in the "back" of the vessel, i.e., in the cleared area, will be pumped into the water network after monitoring. The pipes 12 and the concrete sheathing 14 are then disengaged on site in their ditch 10 using the inside bucket 68. Contaminated soil that is active above a certain point (for example, above 3700 Ba/kg) is then stored in containers 64 covered with vinyl on the inside. The slabs that make up the covering 18 of the sheathing are monitored and stored in the bottom of the container 98. The slabs are removed along a length of 3 meters corresponding to a section T1 to be dismantled (3 meters has been chosen as the length of the section to be dismantled on the basis of the specific length of one flue). The flue thus disengaged is separated by using the block and tackle and the appropriate self-closing pliers to lift a debris recovery sheet covered with a vinyl film and allow it to be placed in the bottom of the trench 10. Optionally, the walls of the flue can be pierced to make it easier to get hold of it. The flue 16 is then detached by cutting with a circular saw at the cement joint between the flues. If need be, the flue is cut using a hydraulic hammer. Then, the elements of the flue are cut, like the plastic pipes, and this debris is stored temporarily in the cart 94. It is possible, for this purpose, to use a basket (not shown) instead of the container 64. The flue 16 is then removed from its ditch and placed in the holding area 90 for monitoring. Depending on the degree of radioactivity, the flue will be either evacuated through the roof of the vessel directly or if contamination is detected (exceeding a set threshold of mass radioactivity, for example 3700 Bq/kg), placed in the anti-radiation container 98. The metal pipes 12 are then taken out by 3-meter section according to the same principle, with prior installation of a recovery plate for the saw debris. The sections sawed are also placed in the anti-radiation container 98. When the container 98 is full, it is evacuated from the vessel by crane through the roof 34, then sent to an appropriate storage area. In the example of implementation of the process according to the invention described here, an anti-radiation container makes it possible to evacuate the debris from dismantling four, 3-meter sections. As a variation, it is possible to have a place to cut the flue in pieces using appropriate tools, for example hydraulic pliers that can burst the walls of the flue. Finally, the ditch per se (soil and walls) is monitored. If the mass activity measured is below an initial threshold determined (for example, 37 Bq/kg), the area and the evacuated soil are considered healthy and inactive. If the mass activity is above this initial threshold and below a second threshold set (for example 3700 Bq/kg), the doubtful soil is removed with buckets and transported to a monitored dump. Lastly, if the mass activity is above this second threshold, the contaminated soil will be removed by one of the buckets and stored in the soil holding container 64. If an outside bucket is used, the contaminated soil is sent into the container 64 by the hopper 76. The second section T2 is then dismantled as described above. Meanwhile, the outside bucket 84 is used for terracing, which permits the next sections to be disengaged and the blocks 20 to be set at 3-meter intervals (the extracted soil is monitored and sorted as described previously). After monitoring and evacuating the rainwater, it is then possible to move the vessel by crane. The vessel illustrated in FIG. 4 shows another embodiment of a vessel according to the invention. This vessel, similar in structure to that of the vessel already described with reference to FIGS. 1 to 3, will not be described completely in detail. In particular, the similar or equivalent elements in the two vessels will have the same reference numbers, plus 100. Only technical changes and/or additions made to the vessel in FIG. 4 will be described in detail. Generally speaking, the changes and/or additions are aimed at further improving protection from contamination during dismantling operations. Looking at FIG. 4, the vessel in the invention 124 (shown in median longitudinal cross section) includes a reinforced deck 126 supported by pillars 40, 42 through support cross beams 210 (shown in transverse section). This arrangement makes it possible to increase the spacing between the pillars 40. As a variation, the support cross beams are placed on longitudinal girders (not shown) set up on each side of the ditch. The deck 126 has a central opening 148 bordered by two beams 196 serving as rails for the cart 194. This cart 194 has also been reinforced to carry an extended hydraulic scoop 180 whose buckets 184 can be moved and replaced during certain operations with other suitable tools. The scoop 180 can thus move with the cart 194 in the opening 148 to place soil taken from the bottom of the ditch 10 in the container 64 (reference 180a shows the scoop in another working position). As before, the steel-concrete container 98 is placed at the other end of the vessel 124 and evacuated through the window 156 of the section 147. The flexible protective curtain 150, designed to insulate the working zone in the ditch from the outside, is composed of a thick vinyl bellows, one end of which is joined to the edge of the central opening 148 and the other end of which has a rigid frame 212 equipped with a gutter for taking the bellows when it is retracted (curtain raised). The curtain 150 is manuevered in extended or retracted position (curtain lowered or raised) by a lifting device with a winch, of which only the maneuvering belts 216 are seen in FIG. 4. To complete the protection against contamination, the curtain 150 is lined on the inside with a double thickness of vinyl (not shown). In the way already shown for vessel 24, vessel 124 has a rigid outside envelope composed of posts 144 and boarding 146 lined with vinyl and a roof 134 equipped with windows 156. The posts 144 support the two rails 174 on which a rolling bridge 172 carrying a block and tackle 170, can move. Moreover, the vessel 124 has a dual locking-room system (not shown) similar to the one (52, 54) described in reference to the vessel 24. Generally, the plane that the floor 126 occupies is (unless specified otherwise) pretty much identical to the one of the floor 26 of the vessel 24 illustrated in FIG. 2. Moreover, the vessel 124 is also assembled from two half shells bolted according to the arrangement described for the vessel 24. The work zone or work area 217 of the ditch 10, in which the section being dismantled is located, is insulated for a time from the outside 219 of the vessel 124 by a movable internal hood 218 covering the central opening 148 and composed of panels 220 made of aluminum covered with vinyl protection and placed on an internal partition 222 surrounding the opening 148. This partition 222 has lighting 224. The contaminated dust is collected by two separate ambient air purification systems in the vessel 124 and in the work area each with its own battery of filters located inside the vessel. The systems, which are not shown in FIG. 4, are composed of a forced ventilation system similar to the one described under reference 60 for the vessel 24 and a moving-head vacuum system that can be placed in the immediate neighborhood of the elements being dismantled (concrete sheathing 14 or pipes 12). These purification systems have an average air flow of around 100 Nm.sup.3 /h. Their working features are such that when the moving head 218 is in place (hood closed), the work area 217 is depressed in relation to the inside of the vessel 219, which is itself depressed in relation to the outside (atmospheric air). The implementation of the process in the invention with the vessel 124 is similar to the one described with the vessel 24. However, the hood 218 permits improved confinement of the contaminated debris and increased protection for the occupants of the vessel. Generally, as much dismantling work as possible is done when the inside hood/cover 218 is in place on the partition 222 to serve as insulation. This is true for cutting and preconditioning the debris from the pipes, slabs and flue under vinyl. Of course, the invention is not limited by the linear nature of the equipment to be dismantled, here described as examples; in particular, the process in the invention can be used for dismantling other types of structures, and the vessel may be adapted to the specifics of the worksite .
042082064	claims	1. A process for producing final product castings of low alloy steel and carbon steel, said castings being characterized by superior internal and surface quality, comprising the steps of: (1) melting selected charge materials in a furnace, (2) transferring the melt from the melting furnace into a refining vessel provided with at least one submerged tuyere, (3) refining said melt in said refining vessel by (4) teeming the melt into a cast product mold, (5) permitting the melt to solidify in the mold, and (6) removing the casting from said mold. 2. The process of claim 1 wherein the oxygen-containing gas stream is surrounded by an annular stream of a protective fluid, said protective fluid functioning to protect the tuyere(s) and surrounding refractory lining from excessive wear. 3. The process of claim 1 wherein the dilution gas is selected from the group consisting of argon, helium, hydrogen, nitrogen, carbon monoxide, carbon dioxide, steam and a hydrocarbon gas. 4. The process of claim 1 wherein the dilution gas is argon. 5. The process of claim 1 wherein the sparging gas is selected from the group consisting of argon, helium, nitrogen and steam. 6. The process of claim 1 wherein the sparging gas is argon. 7. The process of claim 1 wherein the protective fluid is selected from the group consisting of argon, helium, hydrogen, nitrogen, carbon monoxide, carbon dioxide, steam and a hydrocarbon fluid. 8. The process of claim 1 wherein the protective fluid is argon. 9. The process of claim 1 wherein the refining vessel is provided with at least two submerged tuyeres. 10. The process of claim 1 wherein the tuyeres are located in the side-wall of the vessel near the bottom, disposed horizontally, and positioned such that the tuyere axes are asymmetric. 11. The process of claim 1 wherein the absolute pressure of the injected fluids at the tuyere inlets is at least two times the absolute pressure of the fluids at the tuyere outlets.
	abstract	A method for measuring a demagnification of a charged particle beam exposure apparatus includes measuring a first stage position of a mask stage in accordance with a mask stage coordinate system, irradiating a first charged particle beam to a first irradiation position on a specimen through the opening portion of the mask, measuring the first irradiation position in accordance with a specimen stage coordinate system, moving the mask stage to a second stage position, measuring the second stage position of the mask stage, irradiating a second charged particle beam to a second irradiation position on the specimen through the opening portion of the mask measuring the second irradiation position in accordance with the specimen stage coordinate system, and calculating a demagnification of the charged particle beam exposure apparatus from the first and second stage positions and the first and second irradiation positions.
051868881	summary	FIELD OF THE INVENTION The invention relates to a device for recovering and cooling the core of a nuclear reactor in meltdown following an accident. BACKGROUND OF THE INVENTION Pressurized-water nuclear reactors comprise a vessel of generally cylindrical shape enclosing the reactor core, which vessel is disposed with its axis vertical in a cylindrical reactor pit having a lower bottom located vertically below the vessel. The nuclear reactor core is cooled by pressurized water circulating in the primary coolant circuit of the reactor and inside the vessel in contact with the fuel assemblies. In the event of certain accidents arising in the nuclear reactor and resulting in a loss in the cooling function of the core, it is possible, though highly improbable, that serious consequences may ensue if the emergency injection circuits of the reactor cannot be put into operation. It is then possible for an accidental sequence to occur which leads to meltdown of the core in the absence of cooling water, which may involve destruction by piercing of the bottom of the vessel and flow of the mass of the molten core and of the materials surrounding the core into the concrete pit containing the reactor vessel. The contact of the molten mass of the fuel and the materials surrounding the fuel, called corium, the temperature of which may reach 2800.degree. to 3000.degree. C., with the bottom of the concrete reactor pit, in the absence of cooling, may lead to the complete destruction of the bottom of the pit. The corium may then force its way into the raft of the reactor containment shell, destroy this raft and contaminate the water table present in the ground of the nuclear-reactor site. The advance of the corium within the ground may only be stopped when the residual power of the corium has decreased sufficiently. Various devices have been proposed for avoiding contact between the corium and the bottom of the concrete reactor pit. The known devices generally enable the mass of corium to be spread out over a certain surface in order that the power to be removed per unit of surface is as low as possible and is compatible with the possibility of cooling by fluids. It has been proposed, for example, to recover and to contain the corium in a metal bag clad internally with refractory materials whose partial melting absorbs the energy, transiently, and provides a sufficient interval of time to externally immerse the metal bag in a mass of water, so as to remove the residual power of the corium by boiling of the mass of water. The drawback of this device stems from the fact that the refractory materials are most often very poor heat conductors, which has the effect of increasing the equilibrium temperature of the corium which remains in the liquid state. Other devices are known which use refractory hearths continuously cooled by a water circuit. One of the drawbacks of these devices is that the cooling circuit may have failures which are liable to render it at least partially ineffective. Furthermore, the heat exchange is not sufficiently great to prevent the corium from remaining at a high temperature and in the liquid state after its discharge onto the recovery and cooling device. A device is also known which is constituted by a stack of sectional profiles placed horizontally in the bottom of the pit, beneath the bottom of the vessel, in such a manner as to constitute receptacles for the molten corium, so as to disperse the molten mass, to promote its cooling and to enable it to solidify. However, this device has the drawback of not effectively protecting the concrete of the reactor pit when the flow of the corium occurs in a localized manner. The sectional profiles which are disposed in a staggered fashion are then liable to be successively filled with molten corium by local overflow, such that the molten mass may rapidly reach the bottom of the reactor pit. SUMMARY OF THE INVENTION The object of the invention is therefore to propose a device for recovering and cooling the core of a nuclear reactor in meltdown following an accident, the reactor comprising a cylindrical vessel enclosing the reactor core, which vessel is disposed with its axis vertical in a cylindrical reactor pit having a lower bottom located vertically below the vessel, and the recovery device being constituted by a metal structure resting on the bottom of the reactor pit and submerged in a mass of water filling the lower portion of the reactor pit, this device enabling any contact between the mass of the molten core and the concrete of the reactor pit to be prevented and the molten mass to be cooled and solidified rapidly. With this object in mind, the metal structure comprises: a central chimney comprising a cylindrical body disposed coaxially in relation to the reactor pit and a deflecting upper wall inclined in relation to the horizontal plane and disposed above the cylindrical body, PA1 a wall for recovering and cooling the core, which wall is disposed around the body of the chimney and constituted by an assembly of contiguous dihedral elements consisting of metal sheets and having a straight ridge, which elements are fixed radiably around the body of the chimney, by inner end portions, in the region of triangular openings traversing the wall of the body of the chimney, the ridges of the dihedra constituting their upper portion being inclined upwards in the direction of the chimney and the space located between the recovery wall and the bottom of the pit communicating with the chimney via the triangular openings, PA1 a peripheral wall disposed in the vicinity of the internal surface of the reactor pit and formed by vertical dihedra, in such a manner as to provide at least one passage bringing the space located between the recovery wall and the vessel bottom into communication with the internal volume of the reactor pit, above the recovery wall.
048184780	abstract	A BWR fuel assembly includes an outer hollow tubular flow channel, a water cross and a plurality of mini-bundles of fuel rods. The outer channel provides an enclosure for directing the flow of coolant/moderator fluid through the fuel assembly. The water cross extends through the outer channel and has a plurality of radially extending members attached along the interior of the outer channel which divide it into a plurality of separate compartments. One mini-bundle of elongated fuel rods is located in each compartment between the interior of the outer flow channel and exterior of the radially extending members of the water cross. Each fuel rod mini-bundle is comprised of an interior array of fuel rods with each fuel rod being of a first predetermined diameter size, and a peripheral array of fuel rods with each fuel rod being of a second predetermined diameter size greater than the first diameter size. The interior array of fuel rods forms an inner, centrally-located, generally squared pattern, whereas the peripheral array of fuel rods forms an outer, peripherally-located, generally squared annular pattern which surrounds the interior array. The fuel rods in both arrays are aligned with one another in columns and rows. The fuel rods of the interior array are ten to twelve percent less in diameter size compared to the fuel rods of the peripheral array.
	description	It is assumed that it is required to inspect a batch (in other words a set) of nuclear fuel rods. Each rod is a stack of pellets, for example containing uranium oxide and/or plutonium oxide. The pellets in these fuel rods are inspected individually. For example, this can be done using the detector described in the documents mentioned above. The structure of this detector is described with reference to FIGS. 1 and 2 throughout the rest of this description. It is a xcex3 radiation detector that comprises an annular-shaped scintillator 1 associated with three photomultipliers 2, 3 and 4. FIGS. 1 and 2 show a rod 16 to be inspected that is composed of pellets 5. The detector also comprises a diaphragm or collimator 6. This diaphragm limits the xcex3 radiation flux emitted by this pellet towards the scintillator, to approximately the length of each pellet. The three photomultipliers are uniformly distributed around the periphery of the scintillator. The outputs from these photomultipliers are connected to electronic measurement means forming a counting system 7, which will be described later. The scintillator is divided into identical sectors 10, 11 and 12 that are optically isolated from each other and associated with photomultipliers 2, 3 and 4 respectively. This scintillator is preferably of the sodium iodide type, activated with thallium. Layers 13, 14 and 1S of an optical insulator such as aluminium can be seen, that optically isolate the different sectors in the scintillator. FIG. 2 shows a shielded containment E protecting the detector against external xcex3 radiation that could disturb the measurements. It also shows that pellets 5 in rod 16 are contained in cladding 17. This rod is moved along a direction 18 by means not shown. It also shows two annular parts 19 and 20 that form the diaphragm 6 and that are opaque to xcex3 radiation. The spacing between these parts is e, that can be adjusted by means not shown. The rod to be inspected is moved along the axis 21 of the detector. The count system 7 comprises amplifiers-stabilizers 22 associated with photomultipliers, an adder 23 with inputs connected to these amplifiers, and single channel analyzers 24 (four in the example shown in FIG. 2) with inputs connected to the output from adder 23, respectively. A computer 25 is provided for processing of signals output by these single channel analyzers 24. This computer is used with a memory 26 and display means 27 and is also designed to run the software used to simulate the detector response. When a measurement is made on a pellet 5, a total spectrum is obtained for all isotopes in this pellet by summation (number of pulses per energy channel as a function of the energy) and according to the invention, the software simulates the response of the detector D and can therefore produce a spectrum approximately identical to this total spectrum. The simulation of the response of detector D is purely digital and is based on the software that is stored in the memory 26 and in which a number of items are input, namely (a) radioactive emission spectra representative of some radioelements or their mixes and that are also memorized in the memory 26, (b) detection characteristics in the form of coefficients and data modelling the thickness through which xcex3 radiation passes and therefore representing the attenuation, (c) operating characteristics of received xcex3 radiation, in particular representing the detector aperture angle, the detected energy bands and amplification of the electronics and (d) a mathematical motor for individual reproduction of xcex3 radiation emitted for the chosen radioelements or the chosen mixes of radioelements. The generation of representative radiation counts is simulated using a Monte Carlo method using random numbers. Thus, simulated responses of the detector D can be obtained in order to build up regression straight lines similar to those used in prior art but without making a genuine measurement. The detector is simply calibrated with an arbitrary rod in the batch to be inspected, for which the real composition was analyzed in advance. The response of the detector D obtained with this rod can be used to calculate a fictitious mass that will be useful in all subsequent calculations. The following description provides additional information about the simulation. With the software, a count number is calculated and an attempt is made to reproduce the count number for a real pellet. The rod used for the calibration is used to xe2x80x9ccalibratexe2x80x9d the software. The isotopic composition and percent of each radioelement in each pellet in this rod are known. When the simulation is done, the activity of this isotope is calculated for each isotope i contributing to the spectrum, taking account of all energies j and all attenuations k between the scintillator and a fictitious pellet. The mathematical motor makes a gaussian distribution of the energy as a function of the resolution. The result is a simulated spectrum for each isotope i considered. A total spectrum for all isotopes is obtained by summation. Therefore, the response of the detector is simulated. The next step (or the previous step in another particular embodiment) is to use the calibration rod. A true count is obtained for each pellet in the calibration rod, using detector D. The simulation is started. The parameters for the pellet thus inspected are input into the computer. The computer calculates a spectrum for an area of interest (in other words one or several energy bands in which we are interested). If the count obtained by simulation is too high, or if it is not high enough, the fictitious mass is corrected until the count obtained is the same as the count obtained with the actually inspected pellet (the fictitious mass being the mass of the pellet for which it is required to simulate a response by the detector, using the amplitude of the spectrum rather than its shape). When the count obtained is equivalent, in other words when the correct fictitious mass is obtained, this value will be saved and will be used to calculate all other points on regression straight lines. Many other detectors could be used instead of the annular sodium iodide scintillator detector. For example, a plane NaI scintillator detector or a GeLi scintillator detector could be used. The invention can also be used to simulate and inspect other fuel elements than the rods mentioned above for which the pellets are usually cylindrical. For example, plate shaped elements containing non-cylindrical pellets could be simulated and inspected. Furthermore, this invention is not limited to simulation and inspection of nuclear fuel elements. It can be used to simulate and inspect many other radioactive objects, for example receptacles made in series production and containing a radioactive material. The following description of calculation loops that could be used to simulate the response of the detector D mentioned above (FIGS. 1 and 2) to a nuclear fuel pellet 5 formed by a uranium matrix containing several plutonium isotopes (the only isotopes considered in the following calculations), is given for guidance only and is in no way restrictive: 1) Start loop for isotope (i) Activity ( i ) = Av A ( i ) xc3x97 M xc3x97 ti xc3x97 % ⁢ xe2x80x83 ⁢ isotope ( i ) xc3x97 λ ( i ) where: Av=Avogadro""s number=6.022xc3x971023 A(i)=atomic mass of the isotope (i) M=fictitious mass of the pellet ti=isotopic content=percentage of Pu in the matrix %isotope(i)=percentage of isotope(i) contained in the matrix xcex(i)=disintegration constant for isotope(i) 1.1) Start loop for energy (j) Resolution(j)=Energy(j)xc3x97xcex1 Initial flux(i,j)=Activity(i)xc3x97%emission(i,j)xc3x97xcex7/s where: xcex7=geometric efficiency of the detector xcex1=resolution percentage independent of the energy, defined experimentally resolution(j)=resolution of the detector for energy (j) s=surface area of the detector scintillator 1.1.1) Start loop for the attenuator element (k) ì a ⁡ ( i , j , k ) = [ xc3x3 ⁢ xe2x80x83 ⁢ a + xc3x3 ⁢ xe2x80x83 ⁢ a + Z ( k ) ⁢ xxc3x3a PE ( i ; j ; k ) ⁢ PP ( i ; j ; k ) ⁢ C ( i , j , k ) ] xc3x97 n ~ ( k ) xc3x97 Av / A ( k ) where: "sgr"a=effective photoelectric absorption cross-section PE(i,j,k) "sgr"a=Compton effective absorption cross-section C(i,j,k) "sgr"a=Effective cross-section for production of pairs PP(i,j,k) Z(k)=atomic number of the attenuator element (k) xcfx81(k)=density of the attenuator element (k) A(k)=atomic mass of the attenuator element (k) Attenuation coefficient(i,j,k)=exp (xe2x88x92xcexca(i,j,k)xc3x97X(k)) where: X(k)=thickness of the attenuator element (k) Final flux(i,j,k)=Initial flux(i,j,k-1)xc3x97Attenuation coefficient(k) 1.1.2) End loop for the attenuator element (k) with initial flux(i,j,kxe2x88x921) for k=1=initial flux(i,j)NaI scintillator: μ a ( i , j ) ( NaI ) = [ PE ( j ) σa ( NaI ) ⁢ + Z ( NaI ) ⁢ xc3x97 C ( j ) σ ⁢ xe2x80x83 ⁢ a ( Nai ) ] xc3x97 Av A ( NaI ) xc3x97 ρ ( NaI ) Absorption ( i , j ) ⁢ xe2x80x83 ⁢ ( NaI ) = final ⁢ xe2x80x83 ⁢ flux ( i , j , k ) xc3x97 μ a ( i , j ) ( NaI ) xc3x97 X ( NaI ) where ⁢ : ⁢ xe2x80x83 ⁢ xe2x80x83 PE ( j ) σ ( NaI ) = effective ⁢ xe2x80x83 ⁢ photoelectric ⁢ xe2x80x83 ⁢ absorption ⁢ xe2x80x83 ⁢ cross ⁢ - ⁢ section ⁢ xe2x80x83 ⁢ for ⁢ xe2x80x83 ⁢ NaI . Z(NaI)=average atomic number of NaI "sgr"a(NaI)=Compton effective absorption cross-section for NaI C(j) A(NaI)=average atomic mass of NaI xcfx81(NaI)=average density of NaI X(NaI)=NaI scintillator thickness 1.1.3) Start loop for the procedure to draw values for the photoelectric and Compton absorption. N=1200 values vn are calculated by drawing random numbers according to a Gaussian distribution centered on an average value equal to Energy(j) and with a standard deviation equal to Resolution(j). Vn=vnxc3x97Absorption(i,j)NaI ∑ n = 1 N Vn gives absorption spectrum(i,j)NaI 1.1.4) End loop to draw values for the photoelectric and Compton absorption Compton dome: Energy(jxe2x80x2)=hxcexd(j)/(1+2hxcexd(j)/0.511) Resolution(jxe2x80x2)=Energy(jxe2x80x2)xc3x97xcex1 Dome ⁢ xe2x80x83 ⁢ scattering ( j xe2x80x2 ) = xe2x80x83 C ( j xe2x80x2 ) σ ⁢ xe2x80x83 ⁢ dif ⁢ xe2x80x83 ⁢ ( NaI ) xc3x97 z ( NaI ) xc3x97 Final ⁢ xe2x80x83 ⁢ flux ( i , j , k ) xc3x97 Av A ( NaI ) xc3x97 ρ ( NaI ) xc3x97 X ( NaI ) where: h=Planck""s constant xcexd(j)=frequency corresponding to the energy denoted Energy(j), the Compton dome energy specific to NaI and denoted Energy(jxe2x80x2) being the scattered photon energy that is less than Energy(j) xe2x80x83 C ( j xe2x80x2 ) σ ⁢ xe2x80x83 ⁢ dif ⁢ = ( NaI ) xc3x97 Z ( NaI ) xc3x97 Final ⁢ xe2x80x83 ⁢ flux ( i , j , k ) xc3x97 Av A ( NaI ) xc3x97 ρ ( NaI ) xc3x97 X ( NaI ) 1.1.5.) Start loop to draw values for Compton scattering. N=1200 values vn are calculated by drawing random numbers using a Gaussian distribution centered on an average value equal to Energy(jxe2x80x2) and with a standard deviation equal to Resolution(jxe2x80x2) Vn=vnxc3x97Dome scattering(i,jxe2x80x2)NaI ∑ n = 1 N vn gives scattering spectrum(i,j)NaI 1.1.6.) End loop to draw values for Compton scattering. Compton front (the energy of the Compton front being denoted Energy(jxe2x80x3) and less than Energy(j)) Energy(jxe2x80x3)={(2xc3x97hxcexd(j)/0.511)/[1+(2xc3x97hxcexd(j)/0.511)]}xc3x97hxcexd(j) Resolution(jxe2x80x3)=Energy(jxe2x80x3)xc3x97xcex1 Front scattering(jxe2x80x3) = σ ⁢ xe2x80x83 ⁢ dif C ( j xe2x80x3 ) ⁢ ( NaI ) xc3x97 Z ( NaI ) xc3x97 final ⁢ xe2x80x83 ⁢ flux ( i , j , k ) xc3x97 Av A ( NaI ) xc3x97 ρ ( NaI ) xc3x97 X ( NaI ) where: "sgr"dif (Nai)=effective Compton front scattering C(jxe2x80x3) cross-section 1.1.7) Start loop to draw values for the Compton front. N=1200 values vn are calculated by drawing random numbers using a Gaussian distribution centered on an average value equal to Energy(jxe2x80x3) and with a standard deviation equal to Resolution(jxe2x80x3) Vn=vnxc3x97Front scattering(jxe2x80x3), NaI ∑ n = 1 N ⁢ vn ⁢ xe2x80x83 ⁢ gives ⁢ xe2x80x83 ⁢ scattering ⁢ xe2x80x83 ⁢ spectrum ( i , j xe2x80x3 ) ⁢ NaI 1.1.8) End loop to draw values for Compton front scattering. Calculation of the Compton background (the energy of the Compton background being denoted Energy(jxe2x80x2xe2x80x3) and being less than Energy(j)). Energy(jxe2x80x2xe2x80x3)=hxcexd(j)/(1+2hxcexd(j)/0.511) Resolution(jxe2x80x2xe2x80x3): fixed by experience Background scattering(jxe2x80x2xe2x80x3) = xc3x3dif C ⁡ ( j xe2x80x2xe2x80x2xe2x80x2 ) ⁢ ( NaI ) xc3x97 Z ( NaI ) xc3x97 final ⁢ xe2x80x83 ⁢ flux ( i , j , k ) xc3x97 Av A ( NaI ) xc3x97 ρ ( NaI ) xc3x97 X ( NaI ) where: xc3x3dif C ⁡ ( j xe2x80x2xe2x80x2xe2x80x2 ) = effective ⁢ xe2x80x83 ⁢ Compton ⁢ xe2x80x83 ⁢ background ⁢ xe2x80x83 ⁢ scattering ⁢ xe2x80x83 ⁢ cross - section . 1.1.9) Start loop to draw values for Compton background scattering. N=1200 values vn are calculated by drawing random numbers using a Gaussian distribution centered on an average value equal to Energy(jxe2x80x2xe2x80x3) and with a standard deviation equal to Resolution(jxe2x80x2xe2x80x3) Vn=vnxc3x97Background scattering(i,jxe2x80x2xe2x80x3), NaI ∑ n = 1 N ⁢ vn ⁢ xe2x80x83 ⁢ gives ⁢ xe2x80x83 ⁢ scattering ⁢ xe2x80x83 ⁢ spectrum ( i , j xe2x80x2xe2x80x2xe2x80x2 ) ⁢ NaI 1.1.10) End loop to draw values for Compton background scattering. 1.2) End loop for energy (j) 2) End loop for the isotope (i) An area of interest for an energy band of interest is then chosen (for example from 75 keV to 100 keV) and the number of pulses is calculated S = ∑ i , j ⁢ xe2x80x83 ⁢ ∑ n = 1 N ⁢ xe2x80x83 ⁢ ( Vn ⁢ xe2x80x83 ⁢ for ⁢ xe2x80x83 ⁢ absorption ⁢ xe2x80x83 ⁢ spectrum ( i , j ) ⁢ NaI ) in this energy band is then calculated. Therefore we neglected scattering but it could be taken into account in another particular embodiment. Tm, which is the percentage of global idle time specific to the count system 7 of the detector D is then determined experimentally, and Sxtm is calculated. All calculations can then be repeated for other areas of interest, in other words different energy bands.
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	description	This application is a U.S. National Phase Application of PCT International Application Number PCT/DK2012/050511, filed on Dec. 28, 2012, designating the United States of America and published in the English language, which is an International Application of and claims the benefit of priority to European Patent Application No. 11196097.7, filed on Dec. 29, 2011, and U.S. Provisional Application No. 61/581,276, filed on Dec. 29, 2011. The disclosures of the above-referenced applications are hereby expressly incorporated by reference in their entireties. The present invention relates to a system for optically targeting micro objects, and more specifically to a system and method for manipulating and optically targeting micro objects, and corresponding use of such system. Within the field of investigating, manipulating or analysing microscopic objects it is of constant appeal to be able to improve the instruments used to gain information about the examined objects or for manipulating the objects. The reference WO2009/002537 discloses methods and devices which are provided for the trapping, including optical trapping; analysis; and selective manipulation of particles on an optical array. A device parcels a light source into many points of light transmitted through a microlens optical array and an Offner relay to an objective, where particles may be trapped. Preferably the individual points of light are individually controllable through a light controlling device. Optical properties of the particles may be determined by interrogation with light focused through the optical array. The particles may be manipulated by immobilizing or releasing specific particles, separating types of particles, etc. Regardless of the progress made, there still exists a desire in the field to be able to enhance the capabilities of the equipment used. Hence, an improved device and method for investigating, manipulating or analysing microscopic objects would be advantageous, and in particular a more efficient, reliable, simple device and method would be advantageous. It is a further object of the present invention to provide an alternative to the prior art. In particular, it may be seen as an object of the present invention to provide a system for independently holding and manipulating a plurality of microscopic objects and for targeting at least a part of the plurality of microscopic objects that solves the above mentioned problems of the prior art with providing a more efficient, reliable, simple device and method. Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a system for independently holding and manipulating a plurality of microscopic objects and for targeting at least a part of the plurality of microscopic objects within a trapping volume with electromagnetic radiation, the system comprising trapping means for holding and manipulating the plurality of microscopic objects within the trapping volume, electromagnetic radiation targeting means, the electromagnetic radiation targeting means comprising a targeting electromagnetic radiation source for emitting targeting electromagnetic radiation, a primary spatial electromagnetic radiation modulator for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting at least a part of the plurality of microscopic objects within the trapping volume,wherein the trapping means and the electromagnetic radiation targeting means are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated. The invention is particularly, but not exclusively, advantageous for providing a system which enables simultaneous trapping and targeting of micro objects, wherein the trapping and targeting may work in an independent and dynamic manner, such that the trapping (i.e., holding and manipulation of the micro objects) may be varied in time, and where the targeting, i.e., shining electromagnetic radiation, such as light, onto specific parts of the microscopic objects in a corresponding dynamic manner. A possible advantage is that this enables a simple, yet efficient setup for dynamically manipulating and targeting a microscopic object, and in particular it enables a simple, yet efficient setup for dynamically manipulating and targeting a plurality of microscopic objects. By ‘holding and manipulating’ is understood that microscopic objects may be held in a certain position and/or moved and/or rotated, such as is generally known from optical traps. However, the invention is not limited to optical traps, the trapping means is also contemplated to be embodied in the form of magnetic tweezers, magneto-optical traps, sono-tweezing using ultra-sound transducers or traps relying on dielectrophoresis or other trapping schemes known to the person skilled in the art. ‘Electromagnetic radiation’ (EMR) is well-known in the art. EMR is understood to include various types of electromagnetic variation, such as various types corresponding to different wavelength ranges, such as radio waves, microwaves, infrared radiation, EMR in the visible region (which humans perceive or see as ‘light’), ultraviolet radiation, X-rays and gamma rays. The term optical is to be understood as relating to light. EMR is also understood to include radiation from various sources, such as incandescent lamps, LASERs and antennas. It is commonly known in the art, that EMR may be quantized in the form of elementary particles known as photons. In the present application, the terms ‘light’ and ‘optical’ is used for exemplary purposes. It is understood, that where ‘light’ or ‘optical’ is used it is only used as an example of EMR, and the invention is understood to be applicable to also other wavelength intervals where reference is made to ‘light’ or ‘optical’. By ‘targeting’ is understood specifically illuminating a microscopic object or a part of an object, such as a microscopic object, with EMR, such as light. It is understood, that the targeting light may in particular embodiments not be able to optically trap, hold, move or manipulate the microscopic objects. In particular embodiments, the electromagnetic radiation targeting means may not be able to overcome the forces applied by the trapping system. In consequence, a microscopic object which is trapped by the trapping system will remain trapped regardless of the actions of the electromagnetic radiation targeting means. It may be understood, that a microscopic object which is trapped by the trapping system will remain in a spatially stationary position, such as in the same position with respect to the three geometrical axes (commonly referred to as the x, y and z axes), such as with respect to any rotational axes (such as rotations around the x, y and z axes), regardless of the actions of the electromagnetic radiation targeting means. According to an embodiment, there is provided a system for independently holding and manipulating a plurality of microscopic objects and for targeting at least a part of the one or more microscopic objects within a trapping volume with electromagnetic radiation, the system comprising trapping means for holding and manipulating the plurality of microscopic objects within the trapping volume, wherein the trapping means is an optical trapping means comprising a trapping electromagnetic radiation source for emitting trapping electromagnetic radiation, a secondary spatial electromagnetic radiation modulator for receiving and spatially shaping the trapping electromagnetic radiation so as to generate modulated trapping electromagnetic radiation which may be directed towards the plurality of microscopic objects, electromagnetic radiation targeting means (116), the electromagnetic radiation targeting means comprising a targeting electromagnetic radiation source (118) for emitting targeting electromagnetic radiation (132), a primary spatial electromagnetic radiation modulator (120) for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation (136) directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting at least a part of the plurality of microscopic objects within the trapping volume,wherein the trapping means and the electromagnetic radiation targeting means (116) are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated. An advantage of this embodiment may be that it enables independently trapping and targeting a plurality of microscopic objects, such as 100 or more microscopic objects, and furthermore enables trapping and/or targeting the microscopic objects in a trapping volume wherein neither the trapped microscopic objects nor the targeted microscopic objects need to be confined to a plane, but may be dispersed throughout the trapping volume. In an embodiment of the invention, there is provided a system, wherein the electromagnetic radiation targeting means and the trapping means are arranged so that the electromagnetic radiation targeting means may not be able to overcome the forces applied by the trapping system. An advantage of this may be, that the trapped microscopic objects remain trapped regardless of whether they are targeted or not. For example, a microscopic object, e.g., in the form of a spherical bead, which is trapped by the trapping means may simultaneously be targeted with modulated targeting EMR while still remaining trapped by the trapping means. By ‘specifically illuminating’ is understood that the illumination is confined to a small region, such as a microscopic region, such as a region of less than 10000 square micron, such as less than 1000 square micron, such as less than 100 square micron, such as less than 90 square micron, such as less than 80 square micron, such as less than 70 square micron, such as less than 60 square micron, such as less than 50 square micron, such as less than 40 square micron, such as less than 30 square micron, such as less than 20 square micron, such as less than 10 square micron, such as less than 5 square micron, such as less than 1 square micron. By ‘trapping volume’ is understood a region, such as a three-dimensional region, wherein microscopic objects may be held and manipulated by the trapping system. In particular embodiments, the invention further comprises a sample stage for holding a sample, such as a liquid sample while still retaining access to the sample for the trapping means and the EMR targeting means. The trapping volume may in different embodiments have different sizes, such as each of a height-depth-width, being any one of 1-10000 micrometer, such as 1-1000 micrometer, such as 1-100 micrometer, such as 1-10 micrometer, such as 10-10000 micrometer, such as 10-1000 micrometer, such as 10-100 micrometer. In a particular embodiment, the trapping volume is smaller than or equal to 100×100×100 cubic micrometer, such as substantially equal to 100×100×100 cubic micrometer, such as equal to 100×100×100 cubic micrometer. By ‘microscopic object’ is understood an object of microscopic dimensions, such as particles, beads or micro devices having lengths, width and height within a range from 1 nanometer to 1 millimeter, such as within a range from 1 nanometer to 100 micrometers, such as within a range from 1 nanometer to 10 micrometers, such as within a range from 1 nanometer to 1 micrometer. It is further understood, that multiple microscopic objects may, or may not be, linked together via structural elements, such as a rod or a bar. For example, multiple microscopic objects may be joined together and form a micro device, as is shown in the appended figures (such as FIGS. 2, 9, 10, 14, 15). Individual microscopic objects may for example function as optical handles, such as a plurality of microscopic objects functioning as optical handles for a single micro device which may for a structural entity. It is also understood that a micro device may itself be referred to as a microscopic object. By ‘electromagnetic radiation targeting means’ is understood means for targeting at least a part of the plurality of microscopic objects with EMR, such as specifically illuminating one or more distinct regions on one or more microscopic objects within the trapping volume, where region is understood to be a two-dimensional area extending in a plane being orthogonal to an optical axis along a direction of propagation of the modulated targeting EMR. By ‘targeting electromagnetic radiation source for emitting targeting electromagnetic radiation’ is understood a source of EMR which is suited for emitting EMR, which may be used, after having been spatially modulated by the primary spatial electromagnetic radiation modulator, for targeting. By ‘primary spatial electromagnetic radiation modulator’ and/or ‘secondary spatial electromagnetic radiation modulator’ is understood a spatial light modulator (SLM) as is known in the art. It is understood that the primary spatial EMR modulator and/or the secondary spatial EMR modulator may be provided in a number of embodiments including embodiments with movable parts, such as one or more movable mirrors, or embodiments with spatially distributed and electrically addressable elements which change their properties in terms of optical path length, transmittance, and/or reflectivity upon activation. The spatial variations of optical characteristic across the primary spatial EMR modulator and/or the secondary spatial EMR modulator may in specific embodiments be known as a hologram. In a particular embodiment, there is provided a system, wherein the primary spatial EMR modulator (and/or the secondary spatial EMR modulator) comprises diffractive optics (which is described in the reference WO2003/034118 A1 which is hereby incorporated by reference in entirety). In a particular embodiment, the primary spatial EMR modulator (and/or the secondary spatial EMR modulator) comprises a system for providing diffractive beam shaping, such as a system for diffractive optics, such as a system for Fourier holography, such as a system for Fresnel holography, such as a system for holographic optical scattering. Advantages of employing diffractive optics may include compactness in the setup with few additional optical elements required. In an embodiment there is provided a system, wherein the trapping means comprises a setup relying on a Generalized Phase Contrast (GPC). In an embodiment there is provided a system, wherein the electromagnetic targeting means comprises a setup relying on a Generalized Phase Contrast (GPC). In an embodiment there is provided a system, wherein the trapping means comprises a setup relying on holography. In an embodiment there is provided a system, wherein the electromagnetic targeting means comprises a setup relying on holography. It is understood that GPC and holography may each be seen as advantageous in that they each may serve to enable dynamic trapping respectively targeting microscopic objects in three dimensions (3D). By ‘spatially shaping’ is understood that the properties of the EMR beam, such as the light beam, such as the direction, intensity, phase or other parameters is changed by the spatial EMR modulator, such as the primary and/or secondary EMR modulator. In a more particular embodiment, it is understood that the intensity and/or phase profile of the targeting electromagnetic radiation is changed by the spatial EMR modulator. By ‘modulation’ of EMR is understood that the direction, intensity, phase or other parameters of the EMR is changed, such as changed with respect to time so that microscopic objects which change position (such as being moved by the trapping means) over time may be targeted or trapped, such as followed in space by the targeting and/or trapping means over time. According to some embodiments of the invention the primary spatial electromagnetic radiation modulator and/or the secondary spatial EMR modulator is configured for providing a modulated EMR beam, such as modulated light beam, having a substantially flat intensity profile but non-flat phase profile. In particular embodiments, the primary spatial electromagnetic radiation modulator and/or the secondary spatial EMR modulator is configured for providing a phase-only modulation wherein only the phase varies across a spatial electromagnetic radiation modulator (i.e., non-flat phase-profile). In particular embodiments, all other optical characteristics are substantially constant across the modulator. In particular exemplary embodiments of the present invention the spatial light modulator is approximated by a phase-only modulation of an input laser beam in a discrete pixel matrix. Phase-only modulation allows the entire incoming beam power to be diffractively distributed between the stimulation points with minimal power loss. According to some embodiments of the invention the primary spatial electromagnetic radiation modulator and/or the secondary spatial EMR modulator is configured for providing amplitude-only modulation. According to some embodiments of the invention the primary spatial electromagnetic radiation modulator (and/or the secondary spatial EMR modulator) is configured for generating targeting electromagnetic radiation, such as modulated targeting EMR (respectively configured for generating trapping EMR, such as modulated trapping EMR) having a substantially non-flat phase profile and/or a non-flat amplitude profile with respect to the targeting electromagnetic radiation emitted from the targeting electromagnetic radiation source (respectively with respect to the trapping electromagnetic radiation emitted from the trapping electromagnetic radiation source). According to some embodiments of the invention the primary spatial electromagnetic radiation modulator and/or the secondary spatial EMR modulator is configured for providing concurrent phase and amplitude modulation, such as by means of two spatial modulation-subunits arranged for allowing concurrent phase and amplitude modulation of the incoming beam. According to some embodiments, the optics is shared between the electromagnetic radiation targeting means and the trapping means, such as the trapping means being an optical trapping means and a path of rays from the trapping means traverses the optics and a path of rays from the electromagnetic radiation targeting means traverses the optics. According to some embodiments of the invention the primary spatial electromagnetic radiation modulator and/or the secondary spatial EMR modulator is configured for providing spatial polarization modulation. It is noted that the spatial modulation of the primary electromagnetic radiation, such as the targeting EMR, and/or the secondary EMR, such as the trapping EMR, can be done by a spatial electromagnetic radiation modulator, such as described in the reference “Real-time interactive 3D manipulation of particles viewed in two orthogonal observation planes”, Ivan R. Perch-Nielsen, Peter John Rodrigo, and Jesper Glückstad, 18 Apr. 2005/Vol. 13, No. 8/OPTICS EXPRESS 2852, the contents of which are hereby incorporated by reference. It is understood, that ‘targeting EMR’ is used interchangeably with ‘primary EMR’ and that ‘trapping EMR’ is used interchangeably with ‘secondary EMR’. In general, the spatial modulation could be carried out with known spatial light modulators including Liquid Crystal SLMs (LC-SLMs), Micro Electro-Mechanical Systems SLMs (MEMS-SLMs), deformable mirror SLMs, Acousto-Optic SLMs (AO-SLMs), or other types of SLMs. The point is that the targeting EMR and/or trapping EMR may be spatially modulated in a dynamic time framework (spatio-temporal context so to speak). It is further understood, that the SLM may be operated so as to generate multiple independent beams of electromagnetic radiation, so as to enable providing modulated targeting electromagnetic radiation and/or modulated trapping EMR comprising multiple separate beams of EMR directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting, respectively trapping, such as targeting and/or trapping, at least two spatially different microscopic objects. For example, the system may then be enabled to target and/or trap a distinct microscopic object on a first micro device and another distinct microscopic object on the same or another micro device, while any object between or outside of the two distinct microscopic objects may not be targeted and/or trapped, and where each of the specifically targeted and/or trapped distinct microscopic objects may move in space with respect to time independent of the other specifically targeted and/or trapped distinct microscopic object. In a particular embodiment, the at least two spatially different microscopic objects are or may be targeted, respectively trapped, simultaneously. A possible advantage of simultaneous targeting, respectively trapping, may be that it provides a more simple system, since there is no need to switch from targeting, respectively trapping, one microscopic object to targeting, respectively trapping, another microscopic object. Another possible advantage may be that the time averaged intensity of targeting and/or trapping illumination for each targeted and/or trapped microscopic object may be higher, in particular for similar peak intensity. It is also understood that the targeting means may enable targeting a microscopically sized region on any object, including objects being larger than microscopic objects, where the region is understood to be an area which is a two-dimensional area extending in a plane being orthogonal to an optical axis along a direction of propagation of the modulated targeting EMR. By ‘the trapping means and the electromagnetic radiation targeting means are enabled to function independently of each other’ is understood, that the trapping means may be operated independently, i.e., the microscopic objects may be spatially held and manipulated independently of which objects may or may not be targeted. Similarly, the EMR targeting means may be operated independently from the trapping means, i.e., the targeting of the microscopic objects may be carried out independently of which object may or may not be spatially held and manipulated by the trapping means. By ‘micro device’ is understood is understood a device on the scale of micrometers, such as a device having length, width and height within a range from 1 micrometer to 1 millimeter. The micro device is understood to have a function, e.g., having a tip able to penetrate a cell, be chemically functionalized, have optical elements capable of shaping EMR, such as light, or other functions. In particular embodiments, the micro device comprises a number of optical handles, such as beads, such as a plurality of optical handles, which enables controlling the micro device spatially, such as controlling with 3, 4, 5, or 6 degrees of freedom. By ‘translational movement’ is understood movement where the microscopic object is moved from a first position in space to a second position in space. It is understood that there are three spatial dimensions (corresponding to three axis—x, y, and z—in a Cartesian coordinate system), and translational movement in three dimensions thus corresponds to enabling movement in all directions. By ‘rotational movement’ is understood movement where the microscopic object is rotated—a certain angle—around its own centre of gravity. It is understood that there are three spatial dimensions (corresponding to three axis—x, y, and z—in a Cartesian coordinate system), and rotational movement in three dimensions thus corresponds to enabling movement around all axes. Control over rotational movement of a device around at least two axes means that the rotation of the device around 2 axes is controlled, while rotation of the device around the last axis is not necessarily controlled. The ‘trapping means’ is understood to be means for enabling non-contact spatial control over a microscopic object in terms of translational movement in a least one dimension, such as two dimensions, such as three dimensions. In a specific embodiment, the trapping means enables control over a microscopic object in terms of translational movement in three (translational) dimensions, such as along the three geometrical axes (commonly referred to as the x, y, and z axes). This may be advantageous since it allows placing the microscopic object in any position, such as any position within the trapping volume. The microscopic object need thus not be confined to, e.g., certain line (1D) or a certain plane (2D). In specific embodiments, the trapping means enables control over a microscopic object in terms of translational movement in three (translational) dimensions and rotational movement around at least two axes, which may alternatively be formulated as means for enabling simultaneous control over 3 translational degrees of freedom and 2 rotational degrees of freedom, i.e., a total of 5 degrees of freedom. This may be advantageous since it allows placing the microscopic object in any position and any orientation. For example, a micro device as described in FIGS. 2-3 below may be moved around a human cell while always being oriented toward the centre of the cell, such as having the EMR emitting unit pointing toward the centre of the cell. In particular embodiments, said means may be embodied in the form of EMR controllable handles, such as optical handles. A light ray is mathematically described as a one-dimensional mathematical object. As such, a light ray intersects any surface which is not parallel to the light ray at a point. ‘Light ray’ and ‘EMR ray’ are used interchangeably in this application. A light beam may be described as one or more light rays. A light beam therefore intersects a surface which is not parallel to the beam at a plurality of points, one point for each light ray of the beam. Generally, a profile of the light beam refers to an optical characteristic (intensity, phase, polarization, frequency, brightness, hue, saturation, etc.) or a collection of optical characteristics of the locus of all such intersecting points. Typically, but not obligatorily, the profile of the light beam is measured at a planar surface which is substantially perpendicular to the propagation direction of the light. A light beam may be understood as being spatially limited in directions being orthogonal to the direction of propagation, such as the light intensity being substantially zero outside of the light beam. For example, a Gaussian light beam may have a non-zero light intensity in the center of the beam, whereas the intensity decreases with distance (in directions being orthogonal to the direction of propagation) from the center of the beam, so as to be substantially zero, such as zero, far away from the beam centre. Multiple light beams may be understood to be light beams which may be spaced so that the light intensity between the light beams is much smaller than the light intensity in the light beam centres. ‘Light beam’ and ‘EMR beam’ are used interchangeably in this application. The locus of points at which all light rays of the beam has the same phase is referred to as the wavefront of the beam. For a collimated light beam, for example, the wavefront is a plane perpendicular to the propagation direction of the light, and the light is said to have a planar wavefront. Thus, the term “profile” is used to optically characterize the light beam at its intersection with a given surface, while the term “wavefront” is used to geometrically characterize a surface for a given phase. A profile relating to a specific optical characteristic is referred to herein as a specific profile and is termed using the respective characteristic. Thus, the term “intensity profile” refers to the intensity of the locus of all the intersecting points, the term “phase profile” refers to the phase of the locus of all the intersecting points, the term “frequency profile” refers to the frequency of the locus of all the intersecting points, and so on. Similarly to the general profile function, a specific profile function can also be represented by a two-dimensional function. The ‘targeting EMR source’ is a source of electromagnetic radiation and may in particular embodiments be a laser light source. For example, the targeting EMR source can be a monochromatic laser light source or a combination of several monochromatic laser light sources. Lasers which are not strictly monochromatic are also contemplated. When several lasers are employed, they can operate simultaneously or in a time-multiplexed manner. By ‘white light laser’ is meant a super continuum light source. The trapping means may be arranged for holding and manipulating a plurality of microscopic objects. Trapping of multiple microscopic objects, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 100 or 1000 microscopic objects, such as micro devices, may in particular be advantageous in situations where each of the microscopic objects is carrying out a function, such as scanning of the surface, such as the plurality of microscopic objects carrying out a parallel scanning of a surface, since this may accelerate the particular process by a factor scaling with the number of microscopic objects. Trapping of multiple microscopic objects may also be advantageous in situations where the multiple microscopic objects are carrying out different functions which do not merely add up to a juxtaposition of effects, for example if the microscopic objects are working together, for example to both hold, manipulate and optically scan an object, such as a human cell, such as multiple objects, such as multiple cells. In an embodiment there is provided a system, wherein the trapping means enables independently trapping at least 100 microscopic objects, such as at least 200, 500, 750 or 1000 microscopic objects. This may be seen as an advantage, since it enables trapping more microscopic objects than would otherwise have been possible using, e.g., time-sharing of a mechanically rotatable mirror. The present embodiment may be realized, for example, by using a spatial light modulater, such as an electrically or optically addressed spatial light modulator which enables changing its properties locally, such as a GPC setup as described elsewhere in the present application. In some embodiments, there may be a plurality, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000 or more modulated trapping EMR beams for trapping, such as for trapping a corresponding number of microscopic objects. The microscopic objects being trapped may be distributed within one dimension, such as along a straight line, or within two dimensions, such as on a plane, or within three dimensions, such as not being confined to being positioned on a line (1D) or on a plane (2D). According to this embodiment, a plurality of spatially different microscopic objects may be trapped simultaneously where a modulated trapping EMR beam is dedicated to each micro object. A possible advantage of simultaneous trapping may be that it provides a more simple system, since there is no need to switch from trapping one microscopic object to trapping another microscopic object. Another possible advantage may be that the time averaged intensity of the modulated trapping EMR for each trapped microscopic object may be higher, in particular for similar peak intensity. According to another embodiment of the invention, there is provided a system wherein the electromagnetic radiation targeting means is arranged for targeting a plurality of parts on the plurality of microscopic objects. In analogy with the above paragraph, targeting a plurality of parts on the plurality of microscopic objects may be advantageous for accelerating processes and/or for enabling hitherto impossible processes, such as simultaneous scanning of different regions on a microscopic object. In some embodiments, there may be a plurality, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000 or more modulated targeting EMR beams for targeting, such as targeting a corresponding number of microscopic objects, such as a number of regions within the trapping volume, such as being focused at a plurality of spatially distributed focus points within the trapping volume. The focus points may be distributed within one dimension, such as along a straight line, or within two dimensions, such as on a plane, or within three dimensions, such as not being confined to being positioned on a line or on a plane. In an embodiment, there is provided a system wherein the electromagnetic targeting means enables independently targeting at least 100 microscopic objects, such as at least 200, 500, 750 or 1000 microscopic objects. This may be seen as an advantage, since it enables targeting more microscopic objects than would otherwise have been possible using, e.g., time-sharing of a mechanically rotatable mirror. The present embodiment may be realized, for example, by using a spatial light modulater, such as an electrically or optically addressed spatial light modulator which enables changing its properties locally, such as a GPC setup as described elsewhere in the present application. By ‘the trapping means and the electromagnetic radiation targeting means are spatially separated’ is understood that the trapping means and the EMR targeting means occupy different positions in space. It is in particular understood that the physical element (or elements) of the trapping means which are enabling that the position of the trapped microscopic objects may vary with respect to time and the EMR light modulator (which is enabling that the modulated targeting electromagnetic radiation may vary in space with respect to time) are spatially separated. It is also understood, however, that the trapping means and the electromagnetic radiation targeting means may, share certain elements, in particular elements which are stationary, such as a processor for controlling their operation or such as a microscope objective. According to an embodiment of the invention, there is provided a system wherein the trapping means comprises a trapping spatio-temporal unit enabling varying the position of the plurality of microscopic objects, and wherein the trapping spatio-temporal unit and the primary electromagnetic radiation modulator are spatially separated. The ‘spatio-temporal unit’ is understood to be a physical element (or physical elements) of the trapping means which is (are) enabling that the position of the trapped microscopic objects may vary with respect to time. In a particular embodiment, the trapping means is an optical trapping means comprising a secondary spatial electromagnetic radiation modulator, where the secondary spatial electromagnetic radiation modulator is understood to be a spatio-temporal unit. In another example, the spatio-temporal unit is one or more movable mirrors. According to an embodiment of the invention, there is provided a system wherein the trapping means is an optical trapping means. An advantage of employing optical trapping means may be that it is a relatively fast, versatile and precise. A microscopic object may be moved with a resolution of less than 100 micron, such as less than 10 micron, such as less than 1 micron, such as less than 100 nanometer, such as less than 10 nanometer, such as less than 1 nanometer. According to an embodiment of the invention, there is provided a system wherein the trapping means is an optical trapping means comprising a trapping electromagnetic radiation source for emitting trapping electromagnetic radiation, a secondary spatial electromagnetic radiation modulator for receiving and spatially shaping the trapping electromagnetic radiation so as to generate modulated trapping electromagnetic radiation which may be directed towards the plurality of microscopic objects. Optical trapping means are generally known in the art, and understood to comprise optical tweezers, such as scanning optical tweezers, such as holographic optical tweezers (see the reference “Holographic optical tweezers and their relevance to lab on chip devices”, M. Padgett and R. Leonardo, Lab Chip, 2011, 11, 1196, which is hereby incorporated by reference). In a particular embodiment, the optical trapping means is embodied by a setup relying on the Generalized Phase Contrast (GPC) platform. It is contemplated to use any kind of GPC setup, including GPC (which is described in the reference WO1996/034307 which is hereby incorporated by reference in entirety), analog GPC (which is described in the reference WO2009/036761 A1 which is hereby incorporated by reference in entirety), Matched filtering GPC (which is described in the reference WO2007/147497 A1 which is hereby incorporated by reference in entirety), 3D-GPC (which is described in the reference WO2005/096115 which is hereby incorporated by reference in entirety), multifilter GPC (which is described in the reference WO2004/113993 which is hereby incorporated by reference in entirety) and a MOEMS-platform (which is described in the reference WO2006/097101 A1 which is hereby incorporated by reference in entirety). The secondary spatial EMR modulator may be a spatial light modulator (SLM) which is described elsewhere in the present application. In particular, it is understood that the secondary spatial electromagnetic radiation modulator may in particular embodiments apply a spatial modulation of the incident electromagnetic radiation by changing its properties locally, such as an electrically or optically addressed spatial light modulator. The trapping EMR source for emitting trapping EMR may be a light source, such as a LASER source. It is understood that the trapping EMR source and the targeting EMR source may in particular embodiments be the same EMR source, such as a single light source, such as a single laser source. In such embodiments, the EMR from the light source, such as a laser beam, may be split, e.g., using a dichroic mirror. In other particular embodiments the trapping EMR source and the targeting EMR source may be different EMR sources, such as different lasers, such as the trapping EMR source and the targeting EMR source being EMR sources emitting EMR at different wavelengths and/or power levels. In a particular embodiment, the optical trapping means is arranged for employing counter propagating beams. Advantages of using counter propagating beams may include that the requirements for focusing are less demanding and/or that the trapping volume may be larger and/or a working distance may be larger, in particular in a direction parallel with a direction of propagation of the beam(s). The power of any one of the targeting EMR source and the trapping EMR source may be within 1 mW to 1000 W, such as within 1 mW to 100 W, such as within 1 mW to 10 W, such as within 1 mW to 1 W, such as within 10 mW to 1000 W, such as within 100 mW to 1000 W, such as within 1 W to 1000 W, such as within 10 W to 1000 W, may be within 100 mW to 100 W, may be within 100 mW to 10 W, may be within 100 mW to 1 W, may be within 10 mW to 100 W, may be within 100 mW to 100 W, may be within 1 W to 100 W, may be within 10 W to 100 W. According to a further embodiment of the invention, there is provided a system wherein the primary and secondary spatial electromagnetic radiation modulators are physically separated. According to this embodiment, the primary and secondary spatial electromagnetic radiation modulators are spatially separated, which embodies a simple scheme for allowing them to function independently of each other. An advantage of this may be that it simplifies operation of the primary and/or secondary spatial EMR modulator, since each modulator will have to carry out one function only, i.e., trapping or targeting. Another advantage may be that it enables the trapping EMR source and targeting EMR source to emit EMR towards spatially separate EMR modulators, which in turn may enable the EMR light sources to be different, such as having different wavelengths. An advantage of having spatially separate EMR modulators may thus be, that the modulations carried out by targeting EMR modulator does not affect the trapping EMR and vice versa. This may in particular be advantageous if different wavelengths of EMR are used. It is noted, that the response time of the system, based on a liquid crystal SLM with fast ferroelectric liquid crystal, is sub-millisecond. This enables spatially modifying, respectively, targeting EMR and trapping EMR within time intervals which are as short as 0.5 milliseconds. Thus, it may be possible to emit pulses of modulated targeting EMR and modulated trapping EMR within correspondingly short pulses. This short response time may also be utilized for time sharing of the targeting EMR, e.g., for employing several different wavelengths, such as multiple wavelengths each targeting a different part of a microscopic object. It is also contemplated to use a specific wavelength of electromagnetic trapping or targeting EMR, such as 830 nm (which has the advantage that at this wavelength there may be less risk of damaging biological tissue), such as 488 nm, such as 633 nm (which corresponds to a typical HeNe laser), such as 532 nm, such as 1070 nm, such as 1064 nm (which corresponds to a typical ND:YAG laser), such as 532 nm, such as 1550 nm (which has the advantage that it is well suited for transmittance through optical fibers), such as 2 micron or higher. According to another further embodiment of the invention, there is provided a system wherein the modulated trapping electromagnetic radiation and the modulated targeting electromagnetic radiation have different wavelengths, such as the wavelength of the modulated trapping electromagnetic radiation being 1064 nm and the wavelength of the modulated targeting electromagnetic radiation being 532 nm. An advantage of having different wavelengths may be that it enables choosing for each purpose, targeting and trapping, a wavelength which is particularly well suited, with no need to make a compromise in terms of choosing a wavelength which must be suitable for both but might not be the most suitable for each purpose. Another advantage of having different wavelengths may be, that it enables separating the modulated trapping EMR and the modulated targeting EMR in a relatively straightforward manner, e.g., by simply using a wavelength selective filter. This may, for example be advantageous in case a user prefers observing only photons originating from the modulated targeting EMR, because the user may then achieve this by simply using a filter which blocks EMR of wavelengths corresponding to the wavelength of the modulated trapping EMR, but which filter is transparent to wavelengths corresponding to wavelengths of the modulated targeting EMR. It is understood that the filter is then to be inserted in the optical path between the trapping volume and the observer (such as a detector or a camera). According to an embodiment of the invention, there is provided a system wherein the trapping means is an optical trapping means emitting trapping EMR, such as modulated trapping EMR, and wherein the trapping EMR, such as the modulated trapping EMR, and the modulated targeting electromagnetic radiation have different wavelengths. According to an embodiment of the invention, there is provided a system wherein the trapping means is an optical trapping means emitting trapping EMR, and wherein the trapping EMR, such as the modulated trapping EMR, and the modulated targeting electromagnetic radiation have similar wavelengths. According to another embodiment of the invention, there is provided a system wherein the primary spatial electromagnetic radiation modulator is arranged for applying, such as applies, a spatial modulation of the targeting EMR, such as the incident electromagnetic radiation, by changing its properties locally, such as an electrically or optically addressed spatial light modulator. A spatial light modulator typically operates according to the principles of light diffraction wherein each elementary unit (e.g., a pixel) of the modulator locally modulates the phase of a portion of a light beam impinging thereon, to provide a predetermined light profile. According to this particular embodiment, the modification of the EMR, such as light, does not involve moving an element of the spatial light modulator spatially. Rather a local property (such as transparency or optical path length) of the elementary unit is changed. According to another embodiment of the invention, there is provided a system wherein the secondary spatial electromagnetic radiation modulator is arranged for applying, such as applies, a spatial modulation of the trapping EMR, such as the incident electromagnetic radiation, by changing its properties locally, such as an electrically or optically addressed spatial light modulator. According to this particular embodiment, the modification of the EMR, such as light, does not involve moving an element of the spatial light modulator spatially. Rather a local property (such as transparency or optical path length) of the elementary unit is changed. According to another embodiment, there is provided a system, wherein the trapping means is enabling trapping at least two spatially different microscopic objects, where the spatially different microscopic objects may be positioned at spatially different planes with respect to an optical axis of the trapping means, such as the spatially different planes being orthogonal to the optical axis and displaced along the optical axis of the electromagnetic radiation targeting means. According to such embodiment, the trapped microscopic objects are not confined to lie in a particular plane. A possible advantage of this may be that it provides more freedom for trapping objects in the trapping volume, since no precautions in terms of placing the objects to be trapped in a specific plane are needed. In a particular embodiment, the trapping means comprises a GPC system, such as a GPC system with counterpropagating beams. According to another embodiment of the invention, there is provided a system, wherein the position of at least one of the planes with respect to an optical axis of the trapping means may be changed, such as changed dynamically, such as changed during normal use, such as enabling manipulating microscopic objects along an optical axis of the trapping means. The optical axis of the trapping means is understood to be an axis parallel with a direction of propagation of the modulated trapping EMR, such as the trapping EMR in the trapping volume. A possible advantage of being able to move the plane may be that it enables trapping microscopic objects and moving them in a direction being parallel with a direction of propagation of the modulated trapping EMR. In a particular embodiment, the trapping means comprises a GPC system. According to another embodiment of the invention, there is provided a system, wherein the electromagnetic radiation targeting means enabling targeting, such as focusing on, at least two spatially different microscopic objects, where the spatially different microscopic objects may be positioned at spatially different planes, such as focal planes, with respect to an optical axis of the electromagnetic radiation targeting means, such as the spatially different planes being orthogonal to the optical axis and displaced along the optical axis of the electromagnetic radiation targeting means. In particular embodiments, such three-dimensional targeting is realized using adjustable lenses. According to such embodiment, the targeted regions are not confined to lie in a particular plane. A possible advantage of this may be that it provides more freedom for targeting objects in the trapping volume, since no precautions in terms of placing the objects to be targeted in a specific plane are needed. According to another embodiment of the invention, there is provided a system, wherein the position of at least one of the planes, such as focal planes, with respect to an optical axis of the electromagnetic radiation targeting means may be changed, such as changed dynamically, such as changed during normal use, such as enabling targeting microscopic objects along an optical axis of the electromagnetic targeting means. The optical axis of the electromagnetic radiation targeting is understood to be an axis parallel with a direction of propagation of the modulated targeting EMR, such as the targeting EMR in the trapping volume. A possible advantage of being able to move the plane may be that it enables following microscopic objects which move in a direction being parallel with a direction of propagation of the targeting EMR. According to another embodiment of the invention, there is provided a system, wherein the position of at least one of the planes, such as one of the focal planes, with respect to an optical axis may be changed, such as changed dynamically, such as changed during normal use, so as to move from one side of a microscopic object being trapped by the trapping system to the other side of a microscopic object being trapped by the trapping system along an optical axis of the electromagnetic radiation targeting means. An advantage of this may be that it enables targeting microscopic objects on both sides of a targeted microscopic object. According to another embodiment of the invention, there is provided a system further comprising sensing means arranged for determining the position, such as the position and orientation, of one or more microscopic objects, such as the position of the plurality of microscopic objects, such as the position and orientation of the plurality of microscopic objects within the trapping volume. The sensing means serves for sensing information from the trapping volume. The ‘sensing means’ are capable of obtaining information regarding properties of objects or properties in the trapping volume. In exemplary examples the sensing means may be a camera for visually detecting a position or orientation of a micro device, a cantilever, such as an Atomic Force Microscopy (AFM) cantilever for detecting a force within the trapping volume, or an optical sensor for detecting emitted EMR, such as fluorescence, from within the trapping volume. Other types of sensing means are not excluded from the scope of the present invention. The sensing means may furthermore, in specific embodiments, be operably connected to a processor for analyzing the sensed information, such as a processor arranged to carry out image analysis. According to another embodiment of the invention, there is provided a system further comprising a primary controlling means adapted for controlling the electromagnetic radiation targeting means. In a particular embodiment, the sensing means may be arranged for transmitting signals pertaining to the sensed information to the primary controlling means which may control the EMR targeting means based thereon. In a particular embodiment, the primary controlling means may be a processor, such as a computer comprising a processor. According to another embodiment of the invention, there is provided a system further comprising a secondary controlling means adapted for controlling the trapping means. In a particular embodiment, the sensing means may be arranged for transmitting signals pertaining to the sensed information to a secondary controlling means which may control the trapping means based thereon. In a particular embodiment, the secondary controlling means may be a processor, such as a computer comprising a processor. In another particular embodiment, the primary controlling means and the secondary controlling means are comprised within a single unit, such as a single processor. According to another embodiment of the invention, there is provided a system wherein the system further comprises one or more micro devices, the one or more micro devices, such as a plurality of microdevices, being arranged for spatial manipulation by the trapping means, such as the trapping means enabling control over translational movement in three dimensions and rotational movement around at least two axes of the one or more micro devices, and being arranged for receiving the modulated targeting electromagnetic radiation and furthermore shaping, focusing, redirecting the modulated targeting electromagnetic radiation and/or changing the modulated targeting electromagnetic radiation from farfield to nearfield. By having a system comprising one or more spatially controllable micro devices there is provided a system which facilitates manipulation and/or data gathering on the microscale in an efficient and simple manner. It may be seen as an advantage, that the one or more microdevices may be trapped and targeted independently, which may in turn enable a microdevice to be spatially manipulated and/or simultaneously targeted by modulated targeting EMR at any position, i.e., at a position being similar of different from the position where the modulated trapping EMR is incident. This may, for example, be beneficial when the targeting EMR of a primary wavelength is redirected (by the microdevice) onto an object to be examined (by EMR having the primary wavelength), while the modulated trapping EMR of a different secondary wavelength is used for spatially controlling the microdevice. In a particular embodiment, the microdevice is a microdevice for emitting electromagnetic radiation, the microdevice comprising a first electromagnetic radiation emitting unit arranged to emit electromagnetic radiation, means for enabling simultaneous non-contact spatial control over the microdevice in terms of: translational movement in three dimensions, and rotational movement around at least two axes,wherein the means for enabling non-contact spatial control over the microdevice are arranged for being spatially controlled by forces applied by electromagnetic radiation, such as modulated trapping EMR, and wherein the first electromagnetic radiation emitting unit and the means for enabling spatial control over the microdevice are structurally linked,and wherein,the first electromagnetic radiation emitting unit comprising: an electromagnetic radiation in-coupling element arranged to receive incoming electromagnetic radiation, such as a plurality of electromagnetic radiation in-coupling elements, an electromagnetic radiation out-coupling element being structurally linked to the electromagnetic radiation in-coupling element and the electromagnetic radiation out-coupling element being arranged to emit electromagnetic radiation in response to said incoming electromagnetic radiation, such as a plurality of electromagnetic radiation out-coupling elements,and wherein,wherein the electromagnetic radiation in-coupling element is arranged to receive incoming electromagnetic radiation having a first direction and the electromagnetic radiation out-coupling element is arranged to emit electromagnetic radiation having a second direction where the first direction and the second direction are non-parallel, such as an angle between the first and second direction is at least 10 degrees, such as at least 20 degrees, such as at least 45 degrees, orwherein the electromagnetic radiation in-coupling element is arranged to receive incoming electromagnetic radiation having a first direction and the electromagnetic radiation out-coupling element is arranged to emit electromagnetic radiation having a second direction where the electromagnetic radiation out-coupling element is spatially displaced with respect to the electromagnetic radiation in-coupling element along a direction being orthogonal to the first direction, and where the first direction and the second direction are parallel. According to another embodiment of the invention, there is provided a system wherein the system further comprises one or more micro devices, wherein the one or more micro devices are each arranged for holding a microscopic optical element, such as a spherical bead. The micro devices may each have a holding means, such as a ring shaped element, wherein another microscopic element, such as a spherical bead, may be placed and held and manipulated. An advantage of having such micro device may be that it enables spatial control over readily available microscopic element, such as spherical beads, which may be useful as microscopic lenses being operated spatially at the microscale, and possibly within micrometers from an object under examination. According to another embodiment of the invention, there is provided a system wherein the system further comprises an electromagnetic radiation detector arranged for receiving electromagnetic radiation emitted from within the trapping volume, such as emitted from a plurality of microscopic objects, such as emitted from within the trapping volume and traversing the primary electromagnetic radiation modulator. By adding an electromagnetic radiation detector as described, it might be possible to carry out optical analysis of microscopic structures in an effective manner. According to a second aspect, the invention further relates to a method for independently holding and/or manipulating one or more microscopic objects and for targeting at least a part of the one or more microscopic objects within a trapping volume with electromagnetic radiation, the method comprising trapping the one or more microscopic objects within the trapping volume by using a trapping means, receiving and spatially shaping targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation directed towards at least a part of the one or more microscopic objects so as to specifically target at least a part of the one or more microscopic objects within the trapping volume by using an electromagnetic radiation targeting means,wherein the trapping means and the electromagnetic radiation targeting means are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated. This aspect of the invention is particularly, but not exclusively, advantageous in that the method according to the present invention may be implemented by the system according to the first aspect. According to a second aspect, the invention further relates to a use of a system according to the first aspect for independently holding and manipulating one or more microscopic objects, such as a plurality of microscopic objects and for targeting at least a part of the one or more microscopic objects within a trapping volume with electromagnetic radiation. The first, second and third aspect of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. FIG. 1 shows a system (100) for independently holding and manipulating a plurality of microscopic objects (158) and for targeting at least a part of the plurality of microscopic objects within a trapping volume (102) with electromagnetic radiation (138), the system comprising trapping means (142, 128, 130, 158, 160) for holding and manipulating the plurality of microscopic objects within the trapping volume, electromagnetic radiation targeting means (116), the electromagnetic radiation targeting means comprising a targeting electromagnetic radiation source (118) for emitting targeting electromagnetic radiation (132), a primary spatial electromagnetic radiation modulator (120) for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation (136) directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting at least a part of the plurality of microscopic objects within the trapping volume,wherein the trapping means and the electromagnetic radiation targeting means (116) are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated In more detail, the specific trapping means of FIG. 1 is an optical trapping means and is embodied by a light source 142 which emits one or more lower light beams 110, 112 having a lower direction 114 towards a lower dichroic mirror 128 which reflects the lower light beams 110, 112 into a lower microscope objective 158 so as to direct the now re-shaped lower light beams 130, 132 into the trapping volume 102. The specific trapping means of FIG. 1 utilizes counter propagating beams for trapping, so the light source 142 furthermore emits one or more upper light beams 104, 106 having an upper direction 108 towards an upper dichroic mirror 130 which reflects the upper light beams 104, 106 into an upper microscope objective 160 so as to direct the now re-shaped upper light beams 124, 126 into the trapping volume 102. The trapping volume may hold one or more microscopic devices 158, which will be described in greater detail elsewhere in this application. The light source 142 may be a LASER source emitting at 1064 nm. It is understood that the trapping means may comprise one or more secondary spatial EMR modulators (not shown) which receives EMR from an EMR source and generates modified EMR arranged for optical trapping of a plurality of microscopic objects. In a particular embodiment, the trapping means may be embodied by the so-called BioPhotonics Workstation. The BioPhotonics workstation is described in the reference “Independent trapping, manipulation and characterization by an all-optical biophotonics workstation”, by H. U. Ulriksen et al., J. Europ. Opt. Soc. Rap. Public. 3, 08034 (2008) which is hereby incorporated in entirety by reference. The BioPhotonics Workstation uses near-infrared light (λ=1064 nm) from a fibre laser (IPG). Real-time spatial addressing of the expanded laser source in the beam modulation module produces reconfigurable intensity patterns. Optical mapping two independently addressable regions in a computer-controlled spatial light modulator as counter propagating beams in the sample volume enables trapping a plurality of micro-objects (currently generates up to 100 optical traps). The beams are relayed through opposite microscope objectives (Olympus LMPLN 50×IR, WD=6.0 mm, NA=0.55) into a 4.2 mm thick Hellma cell (250 μm×250 μm inner cross section). A user traps and steers the desired object(s) in three dimensions through a computer interface where the operator can select, trap, move and reorient cells and fabricated micro devices with a mouse or joystick in real-time. Videos of the experiments are grabbed simultaneously from the top-view and side-view microscopes. The particular setup depicted in FIG. 1 furthermore comprises a top camera 152 which may be useful for imaging via the upper microscope objective 160, the upper filter 154 and the upper lens 156 the trapping volume 102 from the top. Similarly, the setup comprises a side camera 144 which may be useful for imaging via the side microscope objective 146, the side filter 148 and the side lens 150 the trapping volume 102 from the side. The specific electromagnetic radiation targeting means 116 comprises a targeting electromagnetic radiation source 118 and a primary spatial electromagnetic radiation modulator 120. The targeting electromagnetic radiation source 118 may for example be a LASER source emitting at 532 nm, for emitting targeting electromagnetic radiation 132 in a direction 134 towards the primary spatial electromagnetic radiation modulator 120. The primary spatial electromagnetic radiation modulator 120 is arranged for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation 136 directed towards at least a part of the plurality of microscopic objects. In the particular example of FIG. 1 the modulated targeting electromagnetic radiation 136, which comprises two beams of EMR in the figure, passes through the lower dichroic mirror 128 and is shaped by the lower microscope objective 158 before entering into the trapping volume as indicated in the figure by the two light beams 138 where it can target a region on the plurality of microscopic objects 158. The modulated targeting electromagnetic radiation 136 may also pass through the plurality of microscopic objects, the lower microscope objective 160, the lower dichroic mirror 130, as indicated by the two light beams 140, before being blocked by the upper filter 154 so as not to enter into the top camera 152 through the upper lens 156. Any one of the upper camera 152 and the side camera 144 may be a CCD camera, and may be connected to a processor such as to enable visualizing or storing the obtained images, and/or for utilizing the images for guiding the trapping means and/or the electromagnetic radiation targeting means. Furthermore, FIG. 1 shows primary controlling means 166 and secondary controlling means 167, such as each of the controlling means being a processor arranged for receiving information from sensing means, such as receiving upper view information 162 from the upper camera 152 and/or side view information 164 from side camera 144. The primary controlling means 166 being arranged for sending, respectively targeting controlling information 168, 170 to the primary spatial EMR modulator 120 and the targeting EMR source 118. The secondary controlling means so as to control the EMR targeting means 116 based on the information from the sensing means. The primary controlling means 167 being arranged for sending trapping controlling information 172 to the trapping means for controlling the trapping means. The primary and secondary controlling means 166, 167 may be combined, e.g., into a single processing unit. Furthermore, FIG. 1 shows a dichroic mirror 174 arranged so as to allow passage of the targeting electromagnetic radiation while reflecting EMR which travels along substantially the same path, but in a direction opposite the direction indicated by arrow 134, such as being emitted from within the trapping volume, such as emitted from the microscopic object 158, the thus reflected EMR 178 being captured by a detector 176 such as a CCD camera. It is also contemplated to adapt the system with appropriate filters, such as a filter 180 between dichroic mirror 174 and detector 176, or similar means so as to enable performing fluorescence spectroscopy on the microscopic object with incident EMR from the targeting EMR source 118 and the emitted EMR 178 being captured by detector 176. According to some embodiments of the present invention, there is provided an electromagnetic radiation targeting means which comprises a targeting electromagnetic radiation source and a primary spatial electromagnetic radiation modulator and furthermore optics configured for directing the modulated targeting electromagnetic radiation to one or more target locations within the trapping volume. The light may in such embodiments be directed by means of optics which may include free-space optics (e.g., an arrangement of lenses, microlens arrays, diffractive elements, etc.) and/or guiding optics (e.g., waveguides, optical fibers, fiber bundles, gradient-index (GRIN) fiber lenses, lens-relay endoscopes, etc.) and/or a generalized phase contrast filter (for transforming phase modulations into intensity modulations). Guiding optics are particularly useful when the target location is not optically accessible by direct illumination. According to some embodiments of the invention the primary spatial electromagnetic radiation modulator comprises a liquid crystal, such as a liquid crystal device. In various exemplary embodiments of the invention the wavelengths and intensities of the modulated targeting EMR are selected so as to generate sufficient heat to such that a temperature at a spot within the trapping volume is increased by T_inc, where T_inc may be from about 1° C. to about 10° C., or from about 2° C. to about 7° C., or from about 3° C. to about 6° C., e.g., about 5° C. The system 100 comprises an EMR targeting means 116 which generates a spatially modulated light beam encoded with a stimulation pattern. EMR targeting means 116 can comprise one or more light sources 118 which generate targeting EMR 132, and a primary spatial EMR modulator 120, which is a spatial light modulator (SLM), which performs the modulation. The EMR targeting means is shown as having only one light source 118, this need not necessarily be the case, since the EMR targeting means can have any number of light sources, depending, for example, on the number of different specific wavelength bands which are required to target the microscopic objects. Additional light sources may be added, as is known in the art, e.g., by using one or more dichroic mirrors. The EMR targeting means 116 may comprise both the primary spatial EMR modulator 120 and a primary controlling means 166. The controlling means 166 may receive information from external sources, e.g., sensing means 144,152, and may in response determine a modulation pattern which is formed on the primary EMR modulator 120. The primary spatial EMR modulator 120 receives and modulates targeting EMR 132 in accordance with the modulation pattern. Thus, the primary spatial EMR modulator 120 modulates targeting EMR 132 in accordance with the targeting controlling information 168 to provide modulated targeting EMR 136 constituting a reconstructed targeting pattern for specifically targeting at least a part of the plurality of microscopic objects 158. The spatial variations of optical characteristic across the primary spatial EMR modulator 120 may in specific embodiments be known as a hologram. In specific embodiments, the Fourier holography or Fresnel holography may be employed, such as by using a primary spatial EMR modulator which may be an SLM arranged for modulating the phase profile, such as the primary spatial EMR modulator being a phase-only SLM. The primary controlling means can include a data processor which calculates the pattern and transmits it to the primary spatial EMR modulator 120 either as electrical signals or as optical signals. Primary spatial EMR modulator 120 can comprise a nematic liquid crystal, or a ferroelectric liquid crystal (FLC), the latter being preferred from the standpoint of high response speed. Primary spatial EMR modulator 120 can also comprise an array of mirrors or micromirrors capable of moving over a full wavelength allowing 2 pi of phase control. Targeting EMR 132 from the light source(s) can be directed to primary spatial EMR modulator 120 of the electromagnetic radiation targeting means 116 via one or more optical redirecting and focusing elements. In the representative example illustrated in FIG. 1, the light beam from the targeting EMR source is directly incident on the primary spatial EMR modulator, but could in other embodiments also be, e.g, redirected by one or more mirrors and passes through one or more filters or dichroic mirrors. FIG. 2 shows a perspective view of an exemplary microscopic object 258, the microscopic object 258 features a light in-coupling element 202, a light out-coupling element 204. The light in-coupling element 102 is arranged to receive light and guide the received light into a light guiding element 206 which optically connects the light in-coupling element with the light out-coupling element. Thus, light may be received at light guiding element 202 and guided by light guiding element 206 to the light out-coupling element 204 where it is emitted. The optical elements 202, 204, 206 thus form an EMR emitting unit which enables emission of EMR, such as light. The micro device further comprises means for enabling non-contact spatial control over the micro device, the means being embodied by optical handles 208, 210, 212, 214. The handles may be substantially spherical elements which may enable an optical trapping system to trap each of the handles so as to enable manipulating the micro device, such as manipulating with 6 degrees of freedom, i.e, in all three geometric dimensions, and rotation around all three geometric axes. Each of the optical handles is structurally linked to the light guiding element 206 via linking structures 216, 218, 220, 222. In the present embodiment, the light out-coupling element 204 is shaped conically, an advantage of such shape may be that the micro device thus has a sharp tip which may be used to physically contact and manipulate other objects, such as a biological cell. Another advantage may be that the light out-coupling element may serve as an output element for shaping the EMR emitted from the first EMR emitting unit. FIG. 3 shows a side view of the microscopic object 258 depicted in FIG. 2. In FIG. 3 a bend part 324 of the light guiding element 206 is more clearly seen. The bend part 324 of the light guiding element enables incoming targeting light 326 to be received by the light in-coupling element 202 and to be guided through the light guiding element 206 and through the light out-coupling part 204 as emitted light 328. The skilled person will readily realize that the optical path is bi-directional, and light may consequently also be collected at the light out-coupling element 204, be guided through the light guiding element 206 and emitted from the light in-coupling element 202. FIG. 3 also indicates a length 327 and a height 329 of the micro device. In an exemplary embodiment the length 327 is 35 micrometer and the height 329 is 20 micrometer, but other dimensions in the micrometer region, such as within 1 micrometer to 1 millimeter are conceivable. FIGS. 4-5 show experimental data in the form of images of an embodiment of the micro device. FIG. 4 shows a micro device 2100 which is similar to the embodiment shown in FIGS. 2-3 (notice that the micro device in FIG. 3 is seen from the side and points to the left while the micro device in FIG. 4 is seen from the bottom and points upwards). The micro device in FIG. 4 is shown in a bottom view, i.e., the light guiding element 2106, the linking structures 2116, 2118, 2120, 2122, the optical handles 2108, 2110, 2112, 2114, and the light out-coupling element 2104 are all in the plane of the paper, which is hereafter referred to as the plane of the micro device, while the light in-coupling 2102 element is on the other side of the plane of the micro device with respect to the observer. In the plane of the micro device is also seen a spherical bead 2152, which is optically trapped, just in front (i.e., ‘above’—in the picture) of the micro device. The spherical bead 2152 may act as an output element for shaping the EMR emitted from the first EMR emitting unit. Notice that the linking structures 2116, 2118, 2120, 2122 are slightly rotated (approximately 40 degrees) around an axis orthogonal to the paper so as not to be orthogonal with respect to the guiding element 2106. An advantage of this rotation is that there is provided a backward bending of the linking structures serving to avoid the light guided via guiding element 2106 to be guided into the linking structure. FIG. 5 shows the micro device 2100 of FIG. 4, however, it is noticed that the micro device is reoriented with respect to the view in FIG. 4. In FIG. 5 the micro device is shown in a side view, corresponding to the view in FIG. 3, except that the micro device is rotated 180 degrees around an axis orthogonal to the plane of the paper. FIG. 5 furthermore features the spherical bead 2152, incoming targeting light 2226 and emitted light 2228. FIG. 5 shows that the emitted light 2228 is shaped by the optically trapped spherical bead 2152, and it can be seen that the light is focused at a point 2254 in front of (i.e., to the right of) the micro device. FIGS. 6-8 show light coupling and optical manipulation experiments. FIGS. 6-7 are snapshots showing selective fluorescence excitation of a selected bead from a group of beads 2182, where the group of beads is a vertical column of 4 beads placed in a row being adjacent to each other. The selective fluorescence excitation is carried out using a micro device similar to the micro device schematically illustrated in FIGS. 2-3 and imaged in FIGS. 4-5. FIG. 6 shows that selective illumination of the second bead 2184 from the top of the group of beads 2182, where the selective illumination is made with light coupled in through the light in-coupling element 2102 of the micro device 2100 and emitted via the light out-coupling element 2104. The inset schematically illustrates that only the second bead from the top is excited. FIG. 7 correspondingly shows selective illumination of the third bead 2186 from the top of the group of beads 2182. The inset schematically illustrates that only the third bead from the top is excited. FIGS. 8A-C show experimental snapshots using reversed light coupling: An optically trapped micro device 2100 creates a localized field in front of the light out-coupling element 2104 by means of incoming targeting light 2226 which is coupled into the micro device via light in-coupling element 2102 and a second trapped micro device 2101′ (which is similar micro device 2100 except for a 180 degrees rotation around an axis orthogonal to the plane of the paper) which is manipulated, which in the present case means moved upwards, so as to scan the local field; the reverse-coupled light is visible from a top microscope, as is evident from the lower insets in each of FIGS. 8A-C and in particular the lower inset of FIG. 8B where a bright dot can be observed (as indicated by the arrow in the lower insert of FIG. 8B, which is enlarged in the middle inset). The bright dot corresponds to light which is emitted from the light out-coupling element 2104 of micro device 2100 and collected by a corresponding element on micro device 2100′ and subsequently emitted from the light in-coupling element 2102′ which in this case is emitting light. The scalebar is 10 micron. The middle inset in each of FIGS. 8A-C shows a close-up of the light in-coupling element 2102′ (which here function as an element for light out-coupling) also shown in the lower inset. FIG. 9 shows a SEM image of a representative two-photon polymerized structure being a bent waveguide (bending radius R being approximately 8 micron; width being approximately 1.5 micron) sitting atop a supporting structure having spheroidal handles for optical trapping; the waveguide is connected via reverse-angled rods for minimal light-coupling loss via the support structure. FIG. 10 shows another type of micro device 1058 similar to the micro devices depicted in FIGS. 2-3, except that the light in-coupling element 202 and the bend part 324 of the light guiding element is not present in the micro device of FIG. 10. Furthermore, a light out-coupling element 204 has been replaced with a holding means 1088 which in the present embodiment is a ring-shaped element. The advantage of having a holding means may be that it enables holding and manipulating other objects, such as spherical beads which may be applicable for use as optical elements. For example, a spherical bead which may be provided at a relatively low cost or effort, may in this way be collected and uses as an lens which can be brought relatively close to an object under examination. FIG. 11 is an illustration of the micro device 1058 of FIG. 10 which is here shown with a spherical bead 1052 in the holding means 1088. Incoming light 1090 is collected by the spherical bead, which now works as a lens element, and emitted light 1092 is focused on an object 1094 under examination. FIG. 12 is a side view of micro device 1058. FIG. 13 is a top view of micro device 1058. FIG. 14 is a top view of an alternative embodiment of a micro device with holding means. The basic idea proposed in FIGS. 10-14, is that optically manipulated micro devices, such as micro devices 1058, are designed with a holding means 1088, such as a mechanical tip-shape so that they can “pick up” and hold spherical objects which may function as ball lenses of different sizes (e.g. glass or polymer beads of different sizes) and act as 6 degrees of freedom (DOF) manipulated magnifying glasses on the submicron-scale. The ball lenses (beads) can simply be catapulted by beams and then each appropriate tool will be optically positioned to grip a bead when it slowly falls down similar to an oversize basketball landing in the basket net in slow motion. The ball lenses can be used bi-directionally to both focus independent light and capture and relay radiated light from a specimen. A further generalization of the basic idea involves combining with micro devices with light couplers (such as light in-coupling element 202 of the embodiments depicted in FIGS. 2-3) so the reconfigurable ball lenses can be used from both top and side simultaneously. There is a host of variations on this basic concept. FIG. 15 shows a side view of another type of micro device 1558 similar to the micro devices depicted in FIGS. 10-14, except that the light in-coupling element 202 and the bend part 324 of the light guiding element is present in the micro device of FIG. 15. With the embodiment of FIG. 15, incoming light targeting 326 is guided through the micro device 1558 and collected by the spherical bead 1588, which now works as a lens element, and emitted light 1528 may be focused on any nearby object. In a general embodiment, there is provided a system for independently holding and manipulating a plurality of microscopic objects and for targeting at least a part of the plurality of microscopic objects within a trapping volume with electromagnetic radiation, the system comprising trapping means for holding and manipulating the plurality of microscopic objects within the trapping volume, electromagnetic radiation targeting means, the electromagnetic radiation targeting means comprising a targeting electromagnetic radiation source for emitting targeting electromagnetic radiation, a primary spatial electromagnetic radiation modulator for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting at least a part of the plurality of microscopic objects within the trapping volume,wherein the trapping means and the electromagnetic radiation targeting means are enabled to function independently of each other. In a more particular embodiment, the trapping means and the electromagnetic radiation targeting means are spatially separated. In a more specific version of this general embodiment, there system further comprises one or more micro devices, the one or more micro devices being arranged for spatial manipulation by the trapping means, such as the trapping means enabling control over translational movement in three dimensions and rotational movement around at least two axes of the one or more micro devices. One or more of the microdevices may be arranged for receiving the modulated targeting electromagnetic radiation and furthermore shaping, focusing, redirecting and/or changing the modulated targeting electromagnetic radiation from farfield to nearfield. To sum up, the present invention relates to a system 100 for independently holding and manipulating one or more microscopic objects 158 and for targeting at least a part of the one or more microscopic objects within a trapping volume 102 with electromagnetic radiation 138. The system comprises trapping means for holding and manipulating the one or more microscopic objects and electromagnetic radiationtargeting means (116). The light means comprising a light source and a spatial light modulator which serve to modify the light from the light source so as to enable specific illumination of at least a part of the one or more microscopic objects. The trapping means and the electromagnetic radiation targeting means (116) are enabled to function independently of each other, so that the trapped objects may be moved around without taking being dependent on which parts are being targeted and vice versa. In exemplary embodiments E1-E15, the invention may relate to: E1. A system (100) for independently holding and manipulating a plurality of microscopic objects (158) and for targeting at least a part of the one or more microscopic objects within a trapping volume (102) with electromagnetic radiation (138), the system comprising trapping means (142, 128, 130, 158, 160) for holding and manipulating the plurality of microscopic objects within the trapping volume, electromagnetic radiation targeting means (116), the electromagnetic radiation targeting means comprising a targeting electromagnetic radiation source (118) for emitting targeting electromagnetic radiation (132), a primary spatial electromagnetic radiation modulator (120) for receiving and spatially shaping the targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation (136) directed towards at least a part of the plurality of microscopic objects so as to enable specifically targeting at least a part of the plurality of microscopic objects within the trapping volume,wherein the trapping means and the electromagnetic radiation targeting means (116) are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated. E2. A system according to embodiment E1, wherein the trapping means comprises a trapping spatio-temporal unit enabling varying the position of the plurality of microscopic objects, and wherein the trapping spatio-temporal unit and the primary electromagnetic radiation modulator are spatially separated. E3. A system according to embodiment E1, wherein the trapping means is an optical trapping means comprising a trapping electromagnetic radiation source for emitting trapping electromagnetic radiation, a secondary spatial electromagnetic radiation modulator for receiving and spatially shaping the trapping electromagnetic radiation so as to generate modulated trapping electromagnetic radiation which may be directed towards the one or more microscopic objects. E4. A system according to embodiment E3, wherein the primary spatial electromagnetic radiation modulator and the secondary spatial electromagnetic radiation modulators are physically separated. E5. A system according to embodiment E1, wherein the primary spatial electromagnetic radiation modulator applies a spatial modulation of the incident electromagnetic radiation by changing its properties locally, such as an electrically or optically addressed spatial light modulator. E6. A system according to embodiment E1, wherein the electromagnetic radiation targeting means is enabling targeting, such as focusing, at least two spatially different microscopic objects, where the spatially different microscopic objects may be positioned at spatially different focal planes with respect to an optical axis of the electromagnetic radiation targeting means. E7. A system according to embodiment E6, wherein the position of at least one of the focal planes with respect to an optical axis of the electromagnetic radiation targeting means may be changed. E8. A system according to embodiment E7, wherein the position of at least one of the focal planes with respect to an optical axis may be changed so as to move from one side of a microscopic object being trapped by the trapping system to the other side of a microscopic object being trapped by the trapping system along an optical axis of the electromagnetic radiation targeting means. E9. A system according to embodiment E1, further comprising sensing means arranged for determining the position, such as the position and orientation, of the one or more microscopic objects. E10. A system according to embodiment E3, wherein the modulated trapping electromagnetic radiation and the modulated targeting electromagnetic radiation have different wavelengths, such as the wavelength of the modulated trapping electromagnetic radiation being 1064 nm and the wavelength of the modulated targeting electromagnetic radiation being 532 nm. E11. A system according to embodiment E1, wherein the system further comprises one or more micro devices, the one or more micro devices being arranged for spatial manipulation by the trapping means, such as the trapping means enabling control over translational movement in three dimensions and rotational movement around at least two axes of the one or more micro devices, and being arranged for receiving the modulated targeting electromagnetic radiation and furthermore shaping, focusing, redirecting and/or changing the modulated targeting electromagnetic radiation from farfield to nearfield. E12. A system according to embodiment E1, wherein the system further comprises one or more micro devices, wherein the one or more micro devices are each arranged for holding a microscopic optical element, such as a spherical bead. E13. A system according to embodiment E1, wherein the system further comprises an electromagnetic radiation detector arranged for receiving electromagnetic radiation emitted from within the trapping volume, such as emitted from the one or more microscopic objects, such as emitted from within the trapping volume and traversing the primary electromagnetic radiation modulator. E14. A method for independently holding and/or manipulating one or more microscopic objects and for targeting at least a part of the one or more microscopic objects within a trapping volume (102) with electromagnetic radiation (138), the method comprising trapping the one or more microscopic objects within the trapping volume by using a trapping means (142, 128, 130, 158, 160), receiving and spatially shaping targeting electromagnetic radiation so as to generate modulated targeting electromagnetic radiation (136) directed towards at least a part of the one or more microscopic objects so as to specifically target at least a part of the one or more microscopic objects within the trapping volume by using an electromagnetic radiation targeting means (116),wherein the trapping means and the electromagnetic radiation targeting means (116) are enabled to function independently of each other, and wherein the electromagnetic radiation targeting means enables independently targeting at least two spatially different microscopic objects, and wherein the trapping means and the electromagnetic radiation targeting means are spatially separated. E15. Use of a system according to embodiment E1 for independently holding and manipulating one or more microscopic objects (158) and for targeting at least a part of the one or more microscopic objects within a trapping volume (102) with electromagnetic radiation (138). Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.
	abstract	Methods and apparatuses for shaping an illumination pattern for off-axis lithography are disclosed. A disclosed apparatus includes a first and second reflecting objective. The first reflecting objective includes a first reflective surface that reflects input light having an on-axis illumination pattern through a first focal point. The second reflecting objective includes a second reflective surface that receives the reflected light through the first focal point and through a second focal point aligned with the first focal point, and reflects the reflected light through an output end as output light having an off-axis illumination pattern. A disclosed method includes receiving collimated light with a conventional illumination pattern centered on an optical axis, symmetrically reflecting the collimated light in multiple directions away from the optical axis and reflecting the reflected light to create output light having an off-axis illumination pattern symmetrical about the optical axis.
051679116	abstract	A fuel assembly comprises a plurality of fuel rods which contain nuclear fuel material inside, a lower tie plate which holds the lower end of the fuel rods and has a path inside to lead coolant between the fuel rods, and a channel box which encloses a bundle of the fuel rods. An orifice, in which a plurality of round rods are arranged to cross the coolant flow path, is installed in a through hole at a side wall of the lower tie plate by connecting to the side wall. Orifice coefficient of the orifice becomes large at small flow rate of coolant which supplied to the fuel assembly, and becomes small at large flow rate of coolant. By using the fuel assembly described above, void fraction in a gap region between fuel assemblies can be altered during beginning and end of an operation cycle of the nuclear reactor.
	claims	1. A neutron shielding material composition comprising:a polymerization initiator;a polymerization component;a refractory material having higher density than that of a resin component comprising said polymerization initiator and said polymerization component;a density increasing agent having higher density than that of said refractory material;a boron compound,wherein said neutron shielding material composition maintains the density of a base resin comprising said resin component and said refractory material; andwherein density of the neutron shielding material composition is from 1.62 g/cm3 to 1.72 g/cm3. 2. The neutron shielding material composition according to claim 1, wherein the composition does not comprise a curing agent. 3. The neutron shielding material composition according to claim 1, wherein the polymerization component comprises an epoxy component. 4. The neutron shielding material composition according to claim 3, wherein the epoxy component comprises a hydrogenated epoxy compound. 5. The neutron shielding material composition according to claim 3, wherein the epoxy component comprises a compound of the structural formula (1):wherein X is at least one compound selected from the group consisting of compounds of the structural formulas (2), (3), (4), (5) and (6):wherein R1 to R4 are each independently selected from the group consisting of CH3, H, F, Cl and Br, and n is 0 to 2 in the structural formula (2), R5 to R8 are each independently selected from the group consisting of CH3, H, F, Cl and Br, and n is 0 to 2 in the structural formula (3), n is 1 to 12 in the structural formula (5), and n is 1 to 24 in the structural formula (6). 6. The neutron shielding material composition according to claim 3, wherein the epoxy component comprises a compound of the structural formula (14):wherein n is 1 to 3. 7. The neutron shielding material composition according to claim 3, wherein the epoxy component comprises at least one compound selected from the group consisting of compounds of the structural formulas (7), (8), (15), and (17):wherein R9 is a C1-10 alkyl group or H, and n is 1 to 24; a compound of the structural formula (8):wherein n is 1 to 8; a compound of the structural formula (15):wherein n is 1 to 3; and a compound of the structural formula (17) 8. The neutron shielding material composition according to claim 1, further comprising a compound for increasing the hydrogen content in the composition. 9. The neutron shielding material composition according to claim 1, wherein the compound for increasing the hydrogen content in the composition comprises at least one of compounds of the structural formulas (9) and (10):wherein n is 1 to 3. 10. The neutron shielding material composition according to claim 1, comprising an oxetane compound as the polymerization component. 11. The neutron shielding material composition according to claim 10, wherein the oxetane compound comprises at least one of compounds of the structural formulas (19) and (20) 12. The neutron shielding material composition according to claim 1, wherein the polymerization initiator comprises a cationic polymerization initiator. 13. The neutron shielding material composition according to claim 12, wherein the cationic polymerization initiator comprises a compound of the structural formula (11) or (16):wherein R10 is a hydrogen atom, a halogen atom, a nitro group or a methyl group, R11 is a hydrogen atom, CH3CO or CH3OCO, and x is SbF6, PF6, BF4 or AsF6. 14. The neutron shielding material composition according to claim 1, further comprising a filler. 15. The neutron shielding material composition according to claim 1, wherein the refractory material comprises at least one of magnesium hydroxide and aluminum hydroxide. 16. The neutron shielding material composition according to claim 1, wherein the density increasing agent is a metal powder having a density of 5.0 to 22.5 g/cm3, a metal oxide powder having a density of 5.0 to 22.5 g/cm3, or a combination thereof. 17. A neutron shielding material produced from the neutron shielding material composition according to claim 1. 18. A neutron shielding container produced from the neutron shielding material according to claim 17. 19. The neutron shielding material composition according to claim 15, wherein said magnesium hydroxide is obtained from sea water magnesium.
062691457	abstract	In accordance with the present invention, a compound refractive lens for focusing, collecting and collimating x-rays comprising N individual unit lenses numbered i=1 through N, with each unit lens substantially aligned along an axis such that the i-th lens has a displacement t.sub.i orthogonal to said axis, with said axis located such that the sum of the displacements t.sub.i equals zero, and wherein each of said unit lenses comprises a lens material having a refractive index decrement less than 1 at a wavelength less than 100 Angstroms.
	summary
050911414	description	DETAILED DESCRIPTION FIG. 1 shows the lower part of a steam generator 1 and a part of the bundle 2 of this steam generator, consisting of tubes 3 bent into a U shape. Each of the tubes 3 of the bundle comprises two straight legs whose ends are fixed in holes passing through the tube plate 5 of the steam generator and a curved part 4 arranged in the upper part of the bundle. The tubes 3 are held in a regular arrangement in the bundle by spacer plates such as 6, distributed uniformly along the length of the straight legs of the tubes. The ends of the straight legs of the tubes 3 are level with the lower face 5a of the tube plate 5 forming its entry face. The face 5a of the tube plate forms the upper wall of a water box 7 of hemispherical shape, divided into two parts by a partition 8. Each of the tubes 3 of the bundle comprises a first end opening out into a first part of the water box and a second end opening out into the second part of the water box. In FIG. 1 the steam generator 1 has been shown during positioning of a tool consisting of a heating element inside a tube of the bundle. This operation is performed during a stoppage of the nuclear reactor, the steam generator being cold and empty of water. The water box 7 comprises two manholes 9a and 9b passing through its wall, one on each side of its partition 8. While the reactor is in operation, these manholes are closed by leakproof closure plates; on the other hand, during the stoppage periods of the nuclear reactor, these plates are removed to permit the insertion of tools for working inside the water box of the steam generator, in order to carry out the maintenance and the repair of the steam generator The device for inserting and positioning heating elements which is shown in FIG. 1 comprises a means 10 for pulling and pushing comprising two pairs of motordriven rolls 11. The means of pulling and pushing 10 is extended at its exit end by a guide conduit 12 which is inserted into the water box 7 of the steam generator through the manhole 9a. The end of the guide conduit 12 remote from the pushing and pulling means 10 is fixed in a carrier device 13 permitting this end of the guide conduit 12 to be placed in the extension of an end of any tube 3 of the bundle. The carrier device 13, which may be fixed under the tube plate or which may consist of an arm mounted inside the water box, is a piece of equipment which is conventional within the scope of the maintenance operations on steam generators of nuclear reactors. The device for inserting and positioning a tool which is shown in FIG. 1 additionally comprises an elongate transmission member 14 of a length sufficient to enable the component 14 to be inserted, by means of the guide conduit 12, along the entire length of any tube 3 of the bundle and so as to reemerge through the manhole 9b, as shown in FIG. 1. The elongate transmission member 14 is stored on a winding and unwinding device 15 situated, near the entry end of the pulling and pushing means 10. At its end by which the insertion into the tube 3 is performed, the member 14 comprises a conically shaped guiding and coupling component 16. At the exit end of the tube 3, remote from the entry end situated in the extension of the conduit 12, there is arranged a second guide conduit 17 through which the member 14, passes after having passed through a guiding and measuring device 18. Near the manhole 9b of the water box 7, there is arranged a battery of reels 19 onto each of which is wound an electrical heating element 20 which can be inserted into a tube 3 of the bundle to relieve the stress in its curved part 4. At their end, the electrical heating elements 20 comprise a coupling member 21 enabling the heating element 20 to be connected to the guiding and coupling component 16 of a transmission member 14. The necessary operations for inserting and positioning a heating element in the curved part of a tube 3 of the bundle, which will be described below, are actuated by control and actuation consoles 24 which are connected to the various members of the device and in particular to the winder-unwinder 15 and to the pulling and pushing means 10. At the start of the operation, the elongate member 14 is wholly wound onto the winder-unwinder 15, the end component 16 remaining accessible outside the winder-unwinder. The member 14 is inserted into the pulling and pushing means 10 which is switched on to operate in the pushing direction preceded by the end component 16, the member 14 travels forward inside the guide tube 12 and then inside the tube 3, situated in the extension of the conduit 12 The component 16, forming the end of the member 14, reemerges from the exit end of tube 3 and enters the device 18 and then the guide conduit 17, which causes the component 16 to reach the region of the manhole 9b. The member 14 continues to be moved by pushing until such time as a sufficient length of this flexible member has come out of the water box to make it possible to make the coupling between the component 16 and the coupling device 21 of one of its heating elements 20 which is wound onto a reel 19. The direction of operation of the pulling and pushing means 10 is then reversed, so as to exert a pull on the member 20 by means of the elongate member 14. The corresponding reel 19 is made to rotate and the heating element is thus unwound and then inserted into the water box, into the guide conduit 17 and into the tube 3. The insertion of the heating element into the tube 3 is continued by pulling the elongate transmission member 14 until it has become possible to obtain satisfactory positioning of the heating element in the curve 4. This positioning is checked by measuring the length of the member 14 which has been moved by pulling, starting from a reference position. FIG. 2 shows the curved upper part 4 of a tube 3 of the bundle of a steam generator, during the insertion by pushing of an elongate member 14 consisting of a rabbit according to the prior art. The outer sheath of the rabbit 14 has a diameter which is smaller than the internal diameter of the tube 3 of the bundle. In order to transmit thrust forces in the axial direction of the tube (arrow 25) by means of the rabbit 14, this rabbit must have a relatively high rigidity, while retaining the flexing characteristics which allow it to pass through the curved parts 4 of small radius of curvature. It may be necessary, in fact, to apply relatively large thrust forces, insofar as the forces of friction of the sheath of the rabbit on the inner wall of the tube are themselves large during the passage through the curved parts. Owing to its relative rigidity, the sheath of the rabbit 14 folds in an angular manner, creating fold regions 26, between which the sheath forms rectilinear sections 27. The pushing force must therefore be great, to overcome the frictional and jamming forces of the sheath inside the curved part 4. In particular, the pushing force must be extremely large to ensure the passage of the sheath of the rabbit 14 through the end part 28 of the curve 4. Furthermore, the substantially angularly shaped folds 26 in the sheath of the rabbit 14 produce the risk of causing the breakage of the rabbit, either during its initial movement by pushing, or during the positioning of the tool in the tube by pulling the rabbit. In either case, it is very difficult to recover, inside the tube, the end part of the rabbit and/or the tool attached to this end part. Moreover, as indicated above, during the positioning of the tool by pulling the rabbit 14, the latter undergoes a certain elongation when the pulling forces which are applied exceed a certain level In this case, the positioning of the tool in the tube is controlled only approximately. FIG. 3 shows the elongate transmission member of a device for inserting and positioning according to invention, enabling the above mentioned disadvantages be overcome. The elongate transmission member 30 is produced in a coaxial form and comprises a central part 31 consisting of a metal, for example steel, cable, a flexible plastic sheath 32 arranged around the cable 31 and an assembly of angular members 33 threaded onto the flexible sheath 32. At one of their ends, the cable 31 and the sheath 32 are connected to a conically shaped guiding and coupling component 35 enabling the elongate transmission member to be guided inside a steam generator tube and allowing this elongate transmission member to be connected to a tool such as an electrical heating element. As can be seen in FIGS. 3 and 4, the annular members 33 may consist of straight tube sections arranged in sequence in an adjoining manner. These annular members 33 have an external diameter which is less than the internal diameter of a steam generator tube and an internal diameter which is larger than the external diameter of the flexible sheath 32. In this way, the annular members 33 are mounted so that they can slide freely over the sheath 32. The annular members 33 are all identical and have a length which is substantially equal to their external diameter, i.e., smaller than the internal diameter of the steam generator tubes. In the case of the steam generators of pressurized-water nuclear reactors constructed at the present time, this internal diameter of the tubes of the bundle is about 2 cm. The annular members 33 are threaded adjoiningly onto the sheath 32 and along its entire length, the number of members employed being defined by the length of the sheath corresponding to the length of the elongate transmission member. However, as can be seen in FIG. 3, a clearance 34 is provided, whose total amplitude for all the annular members 33 arranged end to end along the length of the sheath 32 has a value which is substantially equal to the length of one of the members 33. In FIG. 3, the members 33 have been shown adjacent over the entire length of the sheath 32, the clearance 34 being seen as a space between the first annular member 33' and the conically shaped component 35. The annular members 33 is preferably made of a rigid plastic material. FIGS. 5 to 9 show different embodiments of the annular members forming the outer part of the elongate transmission member of the device for inserting and positioning according to the invention. Depending on individual cases, the annular members may all be identical or have different and complementary shapes. In FIG. 5, the annular members consist successively of cylindrical rings 36 chamfered at their ends 37 and of spherical balls 38, through each of which a bore passes in the radial direction. The annular members 36 and 38 are threaded one, in an alternating manner, onto the sheath of the elongate transmission member. In this way, the spherical external surfaces of the balls 38 engage, via their part situated at the periphery of the central bore of the ball 38, in the chamfered parts 37 provided at the end of the rings 36. In this way a very good alignment of the successive annular members in the lengthwise direction of the elongate member can be obtained at the same time as a possibility of deflection of the annular members relative to each other. The bores of the rings 36 and of the spheres 38 have diameters which are larger than the external diameter of the flexible sheath of the elongate member. In addition, the rings 36 and the spheres 38 have identical external diameters. FIG. 6 shows a third embodiment of the annular members forming the outer part of the elongate transmission member. These annular members consist successively, along the length of the transmission member, of a spherical ball 39 comprising a bore in a radial direction and of a ball 40 comprising two concave spherical caps 41 pointed outwards. A bore also passes through the balls 40 in a radial direction, its diameter being substantially equal to the diameter of the bore of the balls 39; this diameter is larger than the external diameter of the flexible sheath of the elongate transmission member. When the balls 39 and 40 are threaded successively onto the flexible sheath of the transmission member, the outer surfaces of the balls 39, around the bore in a radial direction, engage in the concave caps 41 of the balls 40 inserted between the balls 39. In this way, a very good alignment of the assembly of the annular members is obtained along the length of the transmission member, together with a possibility of orienting the members relative to each other. FIG. 7 shows annular members 42 and 43 intended to be threaded successively and alternately onto the flexible sheath of an elongate transmission member. The members 42 consist of rings comprising frustoconical surfaces 44 machined on each of their faces, and the members 43 consist of tubular components chamfered at their ends and inserted between the successive frustoconical surfaces 44 of two components 42, when the members 42 and 43 are threaded onto the sheath of the transmission member. The rings 42 and the tubular components 43 comprise an internal bore whose diameter is greater than the external diameter of the sheath of the transmission member. FIG. 8 shows annular members 45 and 46 arranged in sequence and alternating along the length of the elongate transmission member. The members 45 consist of cylindrical rings comprising frustoconical surfaces 47 machined into each of their faces. The members 46, each of which is inserted between two members 45, consist of spheres through which a bore passes in a radial direction, its diameter being greater than the diameter of the flexible sheath of the elongate transmission member. The outer surfaces of the balls 46, around the bore in the radial direction, come into contact with the hollow frustoconical surfaces 47 of the rings 45. An assembly of annular members is thus obtained step by step, so as to permit their alignment in the lengthwise direction of the elongate member. As before, a possibility of deflecting the members relative to each other is also obtained, to ensure passage through the curved parts of the tubes. FIG. 9 shows successive annular members 48 which are all identical and which consist of cylindrical rings one end of which has the shape of a convex spherical cap 49 and the other end of which comprises a hollow part 50 in the shape of a concave spherical cap. The members 48 comprise an internal bore whose diameter is greater than the external diameter of the flexible sheath of the elongate transmission member. When the members 48 are threaded in sequence onto the flexible sheath of the elongate member, the ends 49 in the shape of a convex spherical cap engage in the hollow parts 50 in the shape of a concave spherical cap so as to ensure a mutual fit and an assembly of the members 48 with a very good alignment in the axial direction of the elongate member, while retaining a possibility of deflecting the members relative to one another, to permit the passage of the transmission member through the curved parts of the tubes. FIG. 10 shows an elongate transmission member 30 of a device for inserting and positioning a tool according to the invention, inside a curved part 4 of a small radius of curvature of a steam generator tube 3 during the movement of the member 30 by pushing inside the tube 3. The thrust is exerted in the direction and the orientation of arrow 51, i.e., in the axial direction of the tube 3. The annular members forming the external part of the transmission member 30 consist of rings 33 such as shown in FIGS. 3 and 4. The central part of the elongate member consisting of the cable 31 and the sheath 32 has a flexibility which enables it to match perfectly the shape of the curved part 4 of the tube 3. In addition, this central part has a diameter which is substantially smaller than the internal diameter of the tube 3, with the result that no frictional contact is produced between the sheath 32 and the internal surface of the tube 3 in the curved part 4. The annular members 33 arranged around the central part provide the guidance of the elongate member as it moves in the tube. These annular members, made of plastic, are not capable of damaging the internal surface of the tube by friction. Moreover, as can be seen in FIG. 10, these members are capable of pivoting slightly relative to each other, to accommodate the curvature of the curved part 4. Each of the annular members 33 bears on the inner surface of the tube 3 along a generatrix 52 whose direction enables the shape of the curve to be matched perfectly. During the movement of the elongate transmission member 30 inside the tube 3, the thrust exerted on the rings 33 which are stacked on each other causes them to move in the straight part of the tube preceding the curved part 4, and in this curved part. On leaving the curved part 4, the annular members 33 stack on each other in the straight part of the tube which is situated following the curved part 4, to form a column 54, in which the annular members 33 about against each other. The clearance 34 corresponding to the difference in length between the central part of the elongate member and the succession of annular members is found again at the exit of the curved part 4, between the last annular member 33' to which the thrust is applied and the upper member 33" of the column 54. The members 33 change from position 33' to 33" under the effect of gravity. The clearance 34, whose value corresponds substantially to the length of an annular member 33, makes it possible to obtain a certain flexibility of the central part of the transmission member consisting of the cable 31 and the sheath 32. The thrust needed to move the elongate transmission member 30 inside the tube 3 can thus be limited to a low level, since the elongate member has a flexibility which allows it to match the form of the curves of the tubes, since no major friction is produced between the outer surface of this elongate member and the internal surface of the tube and since the guidance of the elongate member is nevertheless ensured in an effective manner. When the end of the elongate transmission member comprising the nose cone 35 reaches a position which enables it to be fastened to the end of the tool to be inserted into the tube, this coupling is performed and the direction of actuation of the device for pulling and pushing is then changed The pull applied to the elongate member is transmitted by means of the central metal cable 31, which does not undergo any appreciable elongation. The tool can therefore be placed in the curve 4 in an extremely accurate manner In this stage of movement by pulling, the annular members 33 play no active part. The transmission member of the device according to the invention exhibits very good rigidity in compression when pushed, insofar as the flexible central part is surrounded by a succession of rigid rings. Furthermore, this elongate member exhibits very good flexural characteristics, since its central part is flexible and since its outer part consists of rings which are capable of pivoting relative to each other in the curved parts of the tube. The elongate member of the device according to the invention also exhibits a very good resistance to being distorted by pulling, by virtue of the metal cable forming the core of its flexible central part. When a pulling force is applied to the rings of the transmission member by a pull-push device, for example of the type incorporating rollers, self-jamming of the rings on the central part of the transmission member is produced, and this improves the force transmission conditions and the ease of inserting the transmission member into the tube. Wires or cables such as electrical conductors can be passed between the metal cable and the sheath of the central part of the transmission member. In this way it is possible, for example, to fit a camera or a Foucault current probe or an ultrasonic probe at the end of the transmission member. The annular members forming the outer part of the elongate transmission member of the device may differ in shape from those which have been described It is quite obvious that the means of pulling and pushing the elongate member will need to comprise driving members designed to interact with the annular members chosen to form the outer part of the transmission member. In the case of the steam generators of pressurized-water nuclear reactors, the elongate transmission member will need to have a length of the order of 40 m. The device for inserting and for positioning according to the invention can be employed successively in different tubes of the steam generator bundle for positioning tools in each of these tubes It will be possible to use the tools simultaneously after their positioning. The device according to the invention makes it possible to position tools both in tubes which have curves of a large diameter, of the order of 6 m, and in tubes which have small curves whose diameter is approximately 10 cm. The tools positioned may be of any type and can be employed to perform any operation inside the tube. The invention applies to any steam generator comprising tubes which have a curved part joining two legs of great length The device can be employed to perform an operation in a heat exchanger tube other than a steam generator tube of a pressurized-water nuclear reactor.
052710459	claims	1. An integrated process status overview system for a nuclear power plant, the plant including, wherein the integrated overview system comprises: a screen display for generating an image of the major components and connecting fluid lines in the plant for which the protection system and control system parameters are sensed; means for computing a representative value of a process parameter from the validated signals for the parameter and projecting the parameter representative value adjacent the image of the respective component or line; means for projecting a first symbol adjacent at least the projected representative value indicating whether the value is greater or less than the normal range limits for the parameter; means for projecting a second symbol adjacent the first symbol indicating whether the value is increasing or decreasing in magnitude. means for projecting a plurality of alarm tile images on the screen, each alarm tile corresponding to a condition associated with a parameter of the protection or control system; means responsive to at least one representative value, for visually emphasizing the tile image of an alarm when the condition associated with said alarm exceeds a threshold. means responsive to the protection system and the control system, for projecting symbols on the screen that are indicative of the combination of components and fluid lines that are available for performing a plurality of plant critical functions relating to plant safety and power production, including reactivity control, core heat removal, steam/feed conversion, and electric generation. 2. The overview status system of claim 1 including, 3. The overview status system of claim 1 including, 4. The overview status system of claim 3, wherein the critical functions include reactor coolant system heat removal, reactor coolant system inventory control, and secondary system heat rejection.
	summary
	abstract	A method to clean optical elements of an apparatus, the apparatus being configured to project a beam of radiation onto a target portion of a substrate, the apparatus comprising a plurality of optical elements arranged in sequence in the path of the radiation beam, wherein the cleaning method comprises: cleaning one or more second optical elements of the sequence, which receive one or more relatively low second radiation doses during operation of the apparatus, utilizing cumulatively shorter cleaning periods than one or more first optical elements of the sequence that receive one or more first radiation doses during operation of the apparatus, a second radiation dose being lower than each relatively high first radiation dose.
	abstract	An X-ray illumination optical system for an X-ray reduction projection exposure apparatus includes an oblique projection reflection integrator having a reflection surface provided by a plurality of small cylindrical surfaces arrayed in parallel, to perform Koehler illumination of a region of arcuate shape. It enables X-ray illumination of only an arcuate region and reduces loss of light quantity and exposure time.
	description	1. Field of the Invention This invention relates to an X-ray generating method and an X-ray generating apparatus, which are particularly usable for medical treatment. 2. Description of the Background Art In X-ray photography for medical use, a given X-ray tube is employed, and an X-ray is irradiated onto an object from the X-ray tube so that the X-ray through the object is photographed and detected at a detecting section such as an X-ray sensitivity film, and the thus obtained image is analyzed for the medical use. For example, an X-ray generated from a conventional X-ray tube has an effective focal spot with 1 mm×1 mm. When the irradiated surface area on the object is 10 cm×10 cm, it is necessary to enlarge the x-ray size to 10 cm×10 cm. In this case, the brightness of the X-ray is weakened by a ratio of (1 mm×1 mm)/(100 mm×100 mm). In other words, when the conventional X-ray tube is employed, the brightness of the X-ray is decreased to 10−4 times as the initial brightness of the X-ray from the X-ray tube. Moreover, in the medical use of the conventional X-ray tube, some components with unnecessary wavelength would be cut off with some filters. Thus the unnecessary components can not be removed sufficiently. In order to photograph a moving object such as coronary artery in the medical use at high resolution, it is required to irradiate a high intensity X-ray with excellent parallelism and high power onto the moving object in a short period of time. In the conventional X-ray tube, however, the brightness of the X-ray is remarkably decreased when the X-ray is irradiated onto the moving object and the parallelism of the X-ray can not be realized sufficiently. In this point of view, the medical use of the conventional X-ray tube is restricted and thus, can not be employed for wide medical use. It is an object of the present invention, in view of the conventional problems, to provide an X-ray generating method and an X-ray generating apparatus which can generate a high intensity X-ray with high parallelism and high power. Means for Solving the Problem: In order to achieve the object, this invention relates to a method for generating an X-ray, comprising the steps of: irradiating an energy beam onto a target from an energy beam source, thereby generating an X-ray with an irradiating area to be irradiated onto an object, and introducing said X-ray into a spectrometer, thereby generating an X-ray with parallelism through the selection of wavelength and wavelength range. Also, this invention relates to an apparatus for generating an X-ray, comprising: a target for generating an X-ray through the irradiation of an energy beam, an energy beam source for generating said energy beam to generate said X-ray so as to have an irradiating area to be irradiated onto an object and a spectrometer for selecting wavelength and wavelength range of said X-ray through the introduction of said X-ray so as to generate an X-ray with parallelism from said X-ray. In the present invention, the target is prepared different from the conventional X-ray tube, and the energy beam is irradiated onto the target. Therefore, if the irradiating intensity and irradiating cross section of the energy beam are controlled for the target, the output intensity and brightness of the thus obtained X-ray can be enhanced easily. In this point of view, the output intensity and brightness of the X-ray can be varied in dependent on the object. In the present invention, the X-ray, which is generated from the target, is introduced into the spectrometer. Therefore, the X-ray can be rendered parallelism and the irradiating surface of the X-ray can be increased almost equal to the irradiating surface of the object. Moreover, since the X-ray is introduced into the spectrometer, the wavelength range of the X-ray can be restricted within a given range after the spectrometer. In an aspect of the present invention, the spectrometer includes a crystal plate. In this case, the crystal plate may be two or more crystal plates which are to be combined. At least one of the crystal plates may function as an X-ray surface reflective type crystal plate. At least one of the crystal plates may function as an X-ray transmission type (Laue type) crystal plate. According to this aspect, the intended X-ray with parallelism can be obtained easily. Moreover, if the combination of the crystal plates is varied, the X-ray with the parallelism can be rendered monochromatic. Moreover, the crystal plate is made of a cubic crystal such as LiF so as to function as perpendicularly arranged two crystal plates. In this case, since at least two identical reflection planes orthogonal to one another are included in the cubic crystal, the X-ray is reflected at the two reflection planes by an reflective angle of a when the reflective angle is defined as α. Therefore, since the cubic crystal plate can functions as the two (reflective) crystal plates, the intended X-ray with the parallelism can be obtained under the condition that the number of crystal plate can be decreased. In this case, the X-ray with the parallelism can be rendered monochromatic by the subsequent crystal plate. All of the crystal plates can be X-ray surface reflective type crystal plates or X-ray transmission type crystal plates. Also, one or more of the X-ray surface reflective type crystal plates may be combined with one or more of the X-ray transmission type crystal plates. In order to develop the large cross section of the X-ray, the crystal plate(s) may be made of (a) material(s) selected from the group consisting of silicon, graphite, germanium and quartz, in addition to the crystal plate made of LiF. The crystal plate may be made of a multilayered reflective plate for X-ray. The multilayered reflective plate may be configured such that two or more layers are laminated periodically in order to develop the brightness of the X-ray and the intended monochromatic X-ray can be obtained within a given width by means of X-ray diffraction. In this case, the relation between the wavelength and reflective angle are determined on the periodicity of the multilayered reflective plate. Then, if the layer number and periodicity of the multilayered reflective plate are varied, the width of the reflective X-ray wavelength can be also varied. As described above, since according to the present invention a high intensity X-ray with high parallelism and large cross section which is similar size to the object can be generated. Instead of the conventional X-ray tube, the X-ray source can be preferably usable for medical use. With the X-ray source according to the present invention, the X-ray photography for the moving object such as coronary artery can be realized at high special resolution in high speed because the intended X-ray can be irradiated onto the moving object in a short period of time which is originated from the high power and high parallelism of the X-ray from the X-ray source. For example, if nonionic iodine is injected as contrast agent from a vein of an object and the images in the vicinity of the iodine absorption edge (at the front of the absorption edge and the rear of the absorption edge), which is represented as 33,17 KeV at energy and as 0.3738 Å at wavelength, are photographed by the X-ray from the X-ray source of the present invention, the blood vessel of the object can be imaged clearly. As of now, the imaging technique can be performed by utilizing a high energy synchrotron radiation (SR) (e.g., SR of 6 GeV ring at KEK in Japan or that of 8 GeV ring at SPring-8 in Japan). However, it is difficult to establish the high energy SR ring in a hospital, namely, medical field. In this point of view, the imaging technique can not be established yet, but the present invention can realize the imaging technique by utilizing the high intensity X-ray with high parallelism and high power. The reason to generate such an X-ray with high parallelism by introducing the X-ray into the spectrometer is described as follows. When an X-ray is introduced into a spectrometer such as a crystal or a X-ray multilayered film, the X-ray is diffracted in accordance with the equation of 2d sin θ=nλ (Bragg's equation). Herein, the reference character “d” designates a spacing in the crystal or the X-ray multilayered film, and the reference character “θ” designates incident and diffraction angles of the X-ray for the reflection plane, and the reference character “λ” designates a wavelength of the X-ray, and the reference character “n” designates an integer (order of harmonics). Spacing “d” is defined by Miller index (hkl) and crystal lattice parameters. Thus, the wavelength “λ” can be determined by the given incident angle “θ”. As apparent from the equation, the harmonic wavelength cannot be removed by the diffraction. For example, if the X-ray is a monochromatic X-ray and the shape of which is a straight line, the monochromatic X-ray can be diffracted for the direction of angle θ according to the Bragg's equation and the straight line shape is kept after the diffraction. In this case, all the diffracted X-rays in the straight line must be an X-ray with parallelism. In contrast, the monochromatic X-ray and the shape of which is a very broad line can be diffracted to many different directions according to the incident beam directions which still keep the θ from the diffraction plane. In this case, the thus obtained X-ray can not be an X-ray with parallelism. By disposing a similar crystal (second crystal) such that the reflection plane of the second crystal can be perpendicular to the previous crystal and diffracting the X-ray with non-parallelism at the reflection plane, then, only the X-ray with parallelism part can be diffracted and the diffracted X-ray forms with parallelism. In this way, even though the X-ray is diffracted for some directions containing the θ direction at the crystal, etc., the X-ray through the crystals can be an X-ray with parallelism. In another aspect of the present invention, the X-ray is transmitted through at least one of an absorptive plate and a slit so as to remove components with unnecessary wavelength of the X-ray before the X-ray is introduced into the spectrometer. In this case, the lower energy components of the X-ray can be removed effectively and efficiently. For example, the absorptive plate can be made of an Al plate. The use of the absorptive plate can reduce unnecessary heat load for the spectrometer. Although the thickness of the Al plate can be determined by many parameters such as the intensity and hardness of the X-ray generated from the target and object to be irradiated, for example, the thickness of the Al plate may be defined within a range of 1-10 mm. As described above, if the two or more reflective type crystal plates are combined so that their respective reflection plane are orthogonal to one another, the intended X-ray with the parallelism can be obtained. Then, the X-ray with the parallelism can be rendered monochromatic by the subsequent crystal plate because the unnecessary wavelength components can be removed. The reflective type crystal plates may be made of the same material or respective different materials. In a still another aspect of the present invention, a surface portion of the target to which the energy beam is irradiated is partially melted or completely melted. In the former case, since the intensity of the energy beam can be developed enough to increase the temperature of the target in the vicinity of the melting point thereof, the intensity of the intended X-ray can be also enhanced. In this case, a film may be formed on the surface of the target so as to decrease the evaporation velocity thereof by the energy beam. The film is made of a material selected from the group consisting of BN, graphite, diamond, Be, Al2O3. In the latter case, since the intensity of the energy beam can be developed enough to increase the temperature of the target in the vicinity of the melting point thereof and the irradiating point of the target is melted subsequently commensurate with the shift of the energy beam by the anticathode rotation, the intensity of the intended X-ray can be also enhanced and the target surface can be flattened through the melting of the target so that the target surface can be maintained flat during the irradiation of the energy beam. As a result, the intended X-ray can be obtained without the absorption of the target roughness so that the high intensity of the X-ray can be maintained for a long time. In a further aspect of the present invention, the target is a rotating anticathode and the energy beam is irradiated onto a portion of the anticathode which is against the centrifugal force originated from the rotation of the anticathode. In this case, even though the target is melted partially from the irradiation of the energy beams, the outer splash of the melting area of the target can be repressed effectively and efficiently. Also, since the irradiating position of the energy beam can be shifted, the intended X-ray can be generated constantly in high intensity. The target may be a stationary type target because the rotating anticathode has the complicated structure and becomes expensive. The rotating anticathode may have a cylindrical portion which is provided along the periphery of the rotating anticathode so that the energy beams are irradiated onto the inner wall of the cylindrical portion of the anticathode. In this case, the target melting occurs at the inner wall of the cylindrical portion of the rotating anticathode, the outer splash of the melting area of the rotating anticathode due to the energy beam irradiation can be repressed more effectively. The side wall of the cylindrical portion of the rotating anticathode can be inclined inwardly so that the outer splash of the melting area of the rotating anticathode due to the energy beam irradiation can be repressed more effectively. In contrast, the side wall of the cylindrical portion of the rotating anticathode can be inclined outwardly so that the intended X-ray can be taken easily out of the rotating anticathode under the condition that the outer splash of the meting area of the rotating anticathode can be repressed. Then, the irradiating area of the energy beam in the rotating anticathode can be formed in a V-shaped ditch or a U-shaped ditch so that the outer splash of the melting area of the target due to the energy beam irradiation can be repressed effectively. In this case, the V-shaped irradiating area or the U-shaped irradiating area can be formed in such a shape as the centrifugal force affects the melting area of the target during the rotation of the rotating anticathode. In this case, the target surface roughness of the rotating anticathode can be repressed effectively so that the intended X-ray can be generated constantly in high intensity. In a still further aspect of the present invention, the area around the energy beam irradiating area in the target is made of a material with higher melting point and/or higher thermal conductivity than the target itself. In this case, the cooling efficiency of the target can be enhanced entirely and the deformation of the target can be repressed efficiently so that the intended X-ray can be generated constantly in high intensity over a prolonged period of time. Concretely, the target for generating the intended X-ray is configured such that a cooling water is flowed along the backside of the energy beam irradiating area of the target for the constant cooling of the target. However, if the intensity of the energy beams is set too high and the irradiating period of the energy beams is set too long, the energy beam may penetrate though the target so that the cooling water is leaked to the X-ray generating side, thereby rendering the X-ray generating apparatus with the rotating anticathode malfunction. In this point of view, the target can be a double structured target which is composed of the target metal to emit intended characteristic X-ray and the high melting point and/or high thermal conductivity substance which is provided at the backside of the target so that the energy beam is irradiated onto the target and the cooling medium such as a cooling water is flowed along the backside of the substance. In this case, the energy beams can not penetrate through the target so that the cooling medium can not be leaked to the X-ray generating side, originated from the large heat resistance due to the high melting point of the substance and the large cooling performance due to the high thermal conductivity of the substance. According to the present invention can be provided an X-ray generating method and an X-ray generating apparatus which can generate a high intensity X-ray with high parallelism and high power and which can be utilized in an industrial field such as nano-machine fabrication and integral circuit design or a laboratory field requiring the large surface and parallelism of X-ray such as X-ray topography and imaging. This invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross sectional view illustrating an X-ray generating apparatus according to the present invention, and FIG. 2 is an enlarged cross sectional view illustrating a part of the X-ray generating apparatus illustrated in FIG. 1. The X-ray generating apparatus includes an anticathode chamber 2 for accommodating a rotating anticathode 1, a cathode chamber 4 for accommodating a cathode 3 and a rotation driving chamber 6 for accommodating a driving motor 5 for rotating the anticathode 1 which are located in the vicinity of one another and separated from one another by air-tight members 2a, 4a and 6a in FIGS. 1 and 2. At a separating wall 2b for separating the anticathode chamber 2 and the cathode chamber 4 is formed a small hole 2c for passing electron beams 30 to be emitted from the cathode 3 through the separating wall 2b. Then, at the anticathode chamber 2 and the cathode chamber 4 are provided vacuum outlets 2d and 4d, respectively to which vacuum pumps (not shown) are connected. Herein, a tube may be disposed at the hole 2c. In these figures, although the electron beams 30 is illustrated linearly, the electron beam 30 can be illustrated widely so as to realize a wider irradiating surface for an object. A diode electron beam source or a triode electron beam source is also available as the electron beam source 3 as described below. In this point of view, although it should be that the electron beams 30 is illustrated wider, in this embodiment, the electron beams 30 is illustrated linearly for simplicity. Therefore, the small hole 2c is required to have a size wide enough to pass the electron beams 30 therethrough. The rotating anticathode 1 includes a cylindrical portion 11a made of metal to emit intended characteristic X-ray such as Cu, Mo, W or the like, a circular plate 12 formed so as to close the one opening of the cylindrical portion 11, and a rotating shaft 13 with a center shaft shared with the cylindrical portion 11 and the circular plate 12 which are integrally formed. The interiors of the cylindrical portion 11, the circular plate 12 and the rotating shaft 13 are formed a cavity so that a cooling water can be flowed in the interiors thereof. The electron beam is irradiated onto the inner wall 11a of the cylindrical portion 11. The rotating shaft 13 is supported rotatably by a pair of bearings 13a and 13b which are provided in the rotation driving chamber 6. The rotator 5c of the driving motor 5 is provided at the periphery of the rotating shaft 13, and the stationary inductor 5b to rotate the rotator 5c cover the rotator 5c. A cylinder type motor shaft connected to rotator 5c is tightly fixed to the rotating shaft 13 which is attached to the air-tight seal 13c in the rotation driving chamber 6. At the root of the rotating shaft 13 near the circular plate 12 is provided a rotating shaft-sealing member 13c such as ferrofluid seal for maintaining the interior of the anticathode chamber 2 in vacuum by arranging the rotating shaft 13 and the air-tight vessel 6a under air-tight condition. In the rotating anticathode 1 is inserted a stationary separating member 14 for flowing the cooling water along the inner wall of the electron beam irradiating portion 1a. The stationary separating member 14 is formed in a cylindrical shape, enlarged along the shape of the circular shape 12 and elongated short of the inner wall of the cylindrical portion 11. In other words, the stationary separating member 14 divides the interior space of the rotating anticathode 1 so as to be a double tube structure. The outer tube 14a of the double tube structure is communicated with a cooling water inlet 16. Herein, an axial sealing member 14 is provided at the left-side periphery of the rotating shaft 13 so that the cooling water, which is introduced from the inlet 16, is introduced into the outer tube 14a of the double tube structure so as not to be leaked to the accommodating space where the bearings 13a, 13b and the driving motor 5 are provided. The cooling water, which is introduced from the inlet 16, is flowed in the outer tube 14a of the double tube structure, returned from the inner wall of the cylindrical portion 11 and flowed in the inner tube 14b of the double tube structure. In this case, the inner wall of the electron beam irradiating portion 11a is cooled by the cooling water, and the remnant cooling water is flowed in the inner tube 14b and discharged from the outlet 17. At the air-tight member 2a in the vicinity of the electron beam irradiating portion 11a of the rotating anticathode 1 is provided an X-ray window 21 for taking out an X-ray 20 generated by the irradiation of the electron beams 30 onto the electron beam irradiating portion 11a. At the X-ray window 21 is provided an X-ray transmitting film 22 made of a material which can pass the X-ray therethrough such as Be, Al so that the intended X-ray can be taken out of the apparatus with maintaining the vacuum condition of the anticathode chamber 2. In this embodiment, since the X-ray 20 has a large cross section, almost equal to the effective irradiation surface onto the object, the X-ray window 21 is formed wide enough to pass the wider X-ray therethrough. At the outside of the X-ray window 21 is provided a spectrometer 70 for rendering the X-ray 20 in parallelism. The spectrometer 70 is formed from a crystal plate made of at least one selected from the group consisting of silicon, lithium fluoride (LiF), graphite, germanium and quartz or an X-ray multilayered film reflecting plate. The crystal plates can have the function of X-ray surface reflective type crystal plate and/or the function of X-ray transmission type crystal plate. Also, if the crystal plate is made of cubic crystal such as LiF, there are a lot of pairs of identical reflection planes which are perpendicular one another. Therefore, if such a crystal plate is employed, only the crystal plate can render the X-ray 20 in parallelism. In this point of view, if the crystal plate is employed by itself or in the combination with another crystal plate, the thus obtained X-ray with parallelism can be rendered an monochromatic X-ray with parallelism. The X-ray multilayered reflective film plate is formed such that a few kinds of material are laminated so that a monochromatic X-ray (λ) with a predetermined wavelength range (Δλ) can be obtained through the diffraction of X-ray. In this case, the relation between the wavelength and reflective angle of the X-ray to be generated is determined by the periodic length of multilayered film reflective plate for the x-ray. If the number of layers and/or the layer periodicity of the multilayered film reflective plate for X-ray is varied, the width of the X-ray wavelength can be varied. Moreover, two or more crystal plates may be employed. In this case, some components with unnecessary wavelengths of the X-ray can be removed. The crystal plates may be similar crystal plates, but may be different crystal plates. The electron beam source 3 in FIG. 1 may be any type of electron beam source in dependence on the use thereof. In the case that the X-ray generating apparatus as illustrated in FIGS. 1 and 2 is employed for medical use. For example, the X-ray with parallelism 40 is finally required to have the irradiation area in the order of several centimeters through several ten centimeters. It is desired to employ an anode containing tube type electron beam source and it is also desired to employ a triode tube type source to produce a pulse X-ray. A predetermined voltage is supplied to the electron beam source 3 from the high voltage introducing section 31. Then, the X-ray generating method using the X-ray generating apparatus illustrated in FIGS. 1 and 2 will be explained below. As described above, the cooling water is introduced from the inlet 16, and the rotating anticathode 1 is rotated around the rotating axis at high speed and moved repeatedly along the rotating axis as occasion demands by the driving motor 5. At the same time, the electron beams 30 is irradiated onto the electron beam irradiating portion 11a of the anticathode 1 from the cathode, thereby generating the X-ray 20. In this case, the intensity of the electron beams 30 is set to a one which can melt the electron beam irradiating portion 11a at least partially or entirely. When the electron beams 30 with intensity high enough to melt the electron beam irradiating portion 11a at least partially is irradiated, the portion 11a can be heated to a temperature in the vicinity of the melting point thereof (e.g., the melting point of W). As a result, an X-ray with high intensity can be generated from the rotating anticathode 1 (electron beam irradiating portion 11a). Also, when the electron beams 30 with intensity high enough to melt the surface of the electron beam irradiating portion 11a entirely is irradiated, electron beam irradiating portion 11a of anticathode 1 can be flattened continuously so that the electron beam irradiating portion 11a of the rotating anticathode 1 can have the plane surface during the irradiation of electron beams 30. As a result, the generated X-ray can not be absorbed at the protrusions due to the surface roughness of the electron beam irradiating portion 11a of the rotating anticathode 1 so that the X-ray 20 can be generated stably for a long period of time with maintaining the high intensity of the X-ray 20. In this embodiment, the surface roughness of the electron beam irradiating portion 11a of rotating anticathode 1 can be reduced to 1 μm or below as the surface average roughness, and particularly 100 nm or below as the surface average roughness under the very large centrifugal force (rotation speed: 12,000 rpm, diameter of anticathode: 280 mm). In other words, in this embodiment, the surface of the electron beam irradiating portion 11a of the rotating anticathode 1 can be maintained flat for a long period of time. In a conventional technique, in contrast, the surface roughness of the rotating anticathode will be increased to a range of 2-10 μm after long use. Therefore, it is apparent from this embodiment that the intended X-ray with high intensity can be generated stably for a long period of time due to the small surface roughness. In this embodiment, since the electron beam irradiating portion 11a is positioned at the inner wall of the cylindrical portion 11 of the anticathode 1, the inner wall may be melted at least partially by the irradiation of the electron beams. However, since the electron beam irradiating portion 11a is positioned against the centrifugal force from the rotation of the rotating anticathode 1, the melted portions of the inner wall can not be splashed outside. In this embodiment, a special process is not carried out for the cylindrical portion 11a of the rotating anticathode 1 so that the electron beam irradiating portion 11a is positioned on the inner wall of the cylindrical portion 11 under the condition that the side wall of the cylindrical portion 11 is set parallel to the rotation axis. However, the inner wall of the cylindrical portion 11 can be inclined by several tenths of one degree (some second) through several degrees. Concretely, the inner wall of the cylindrical portion 11 can be inclined inwardly toward the rotating axis by several tenths of one degree through several degrees. In this case, the electron beam irradiating portion 11a, even though melted, the outer splash of the electron beam irradiating portion 11a can be prevented more effectively. In contrast, the inner wall of the cylindrical portion 11 can be inclined outwardly from the rotation axis by several tenths of one degree through several degrees. In this case, the intended X-ray can be taken easily out of the apparatus under the condition that the outer splash of the electron beam irradiating portion 11a melted can be prevented. If the electron beam irradiating portion 11a is formed such that the cross sectional shape becomes a V-shaped ditch or a U-shaped ditch, the outer splash of the electron beam irradiating portion 11a can be prevented more effectively. In this case, the width and depth of the V-shaped ditch or the U-shaped ditch are determined so that the intended X-ray can be taken easily out of the apparatus. In addition, if the electron beam irradiating portion 11a is made of a target material in dependence on the wavelength of characteristic X-ray to be generated and the area around the electron beam irradiating portion 11a is made of a material with higher melting point and/or higher thermal conductivity than the target material, the cooling efficiency of the anticathode 1 can be enhanced entirely so that the anticathode 1 can not be deformed. In this case, the intended X-ray can be generated constantly over a prolonged period of time. Furthermore, the anticathode 11, particularly the cylindrical portion 11a to which the electron beams 30 is irradiated, may be made of the target material and the high melting point and/or high thermal conductivity substance may be provided at the backside of the target material so that the inside of the cylindrical portion 11 can be a double structure. In this case, while the intended X-ray is generated by the irradiation of the electron beams 30 onto the cylindrical portion 11, which is cooled by a cooling medium, so that the electron beams 30 can not penetrate through the cylindrical portion 11a on the synergy effect of the large heat resistance and the large cooling effect which are originated from the high melting point and/or the high thermal conductivity of the substance provided at the backside of the target material. As a result, the cooling medium can not be leaked. As the cooling medium can be exemplified a cooling water and a cooling oil. The X-ray 20 generated from the rotating anticathode 1 (cylindrical portion 11a) is introduced into a spectrometer 70 so that the intended X-ray 41 with parallelism, which is extracted from the X-ray 20, can be obtained. In this case, the X-ray 41 includes components within a given wavelength range. Therefore, when the X-ray 41 with parallelism is employed for medical use, a given diseased part can be imaged at high resolution under low dosage exposure due to the parallelism and narrow wavelength width intended of the X-ray 41. As described above, since the intensity (brightness) of the X-ray 20 is strong, the intensity of the X-ray 41 is also strong. As a result, a moving object such as coronary artery can be imaged on the synergy effect of the high resolution by the high parallelism of the X-ray 41 and high intensity of the X-ray 41 by the exposure in a short period of time. In this embodiment, since the electron beam irradiating portion 11a is melted, the metallic vapor pressure may increase by the melting of the target material in the anticathode chamber 2, thereby contaminating the X-ray transmitting window 22. In this case, a rolled protective film, which is made of Ni, BN, Al or mylar against recoiled electrons and exchangeable, may be provided in front of the X-ray transmitting window 22. The rolled protective film is tensed between the supplying roll and the winding roll which are provided inside the X-ray window 21. The thickness of the protective film is appropriately adjusted in view of the recoil electron energy and the X-ray absorption. In this embodiment, although the electron beam is employed as the energy beam, another energy beam such as laser beam and ion beam may be employed. In this embodiment, the back side 11a of the cylindrical portion 11 may be made some material such as stainless steel, Mo, Cu. In this embodiment, although the rotating anticathode is employed, a planer anticathode may be employed when the electron beam irradiating portion is not melted, thereby generating the X-ray with not high intensity. FIG. 3 is a structural view illustrating another X-ray generating apparatus using a stationary and planer target. The same reference numerals are imparted to like components throughout FIGS. 1-3. In this case, an X-ray with large irradiating area can be generated so that the structure of the spectrometer to be used is important. In this point of view, in this embodiment, the structure of the spectrometer will be described in detail. In the X-ray generating apparatus illustrated in FIG. 3, an anticathode 51 is disposed in a vacuum chamber 50, and a cathode 52 is disposed opposite to the anticathode 51. The cathode 52 is fixed inside the wehnelt 53 via an insulating material such as ceramic material. A given voltage is applied between the cathode 52 and the wehnelt 53 so that the wehnelt 53 functions as a lens for electron beams. An aperture grid 54 and an anode 55 are provided between the anticathode 51 and the cathode 52. The electric potential of the aperture grid 54 can be varied within a range of ±7 kV for the cathode 52 in accordance with various conditions. If the electric potential of the aperture grid 54 is set negative for the cathode 52, the electron beams is cut off. If the electric potential of the aperture grid 54 is set positive for the cathode 52, the space charge from the cathode 52 can be compensated so that electrons can be extracted from the cathode 52. According to the aperture grid 54, in this embodiment, the current of the electron beams can be varied by controlling the aperture grid 54 voltage. According to the anode 55, the electron beams 30 emitted from the cathode 52 can be accelerated by the electric potential between the cathode 52 and the anode 55. After passing though anode, the electron beams 30 travel with no electronic potential field to the anticathode 51. Thus, the influence of the high temperature of the target can be reduced by the anode 55. When the anode 55 is not essential, the anode 55 may be omitted. In this embodiment, shown in FIGS. 3 and 4, since the cathode 52, the aperture grid 54 and the anode 55 are provided, namely, the X-ray generator constitutes a triode type. At the vacuum chamber 50 is provided an X-ray transmission window 56 through which the X-ray 20 generated from the anticathode 51 can be taken out of the chamber. Normally, the grid is formed in mesh type produce shorter than msec pulse electron beam with high efficiency, but in this embodiment, if the grid is formed in mesh, the electron beams can not be irradiated uniformly onto the anticathode 51 and the mesh is heated by electric current and damaged easily when it is used to produce longer pulse, especially direct current. For example, the electron beams passing through the openings of the grid can be irradiated sufficiently onto the anticathode 51, but the electron beams collided with the lines of the grid can not be irradiated sufficiently onto the anticathode 51. In this point of view, in this embodiment, the grid is formed in a circle type so that the electron beams 30 can pass through the opening inside the circular grid. In this way, the circular grid is called as the aperture grid. In this embodiment, other parts such as the anticathode 51 and vacuum chamber 50 except the X-ray transmission window 56 of the X-ray generating apparatus is cooled with insulating oil. However, a pipe may be attached to the part to be cooled such as the anticathode 51. In this case, a cooling medium is circulated in the pipe. An advantage of circulated type is that the anticathode 51 can be set in the vacuum chamber 50 entirely under not deformation by the pressure from outside. Then, a first crystal plate 61 and a second crystal plate 62 are provided by a given angle outside of the X-ray transmission window 56 at the vacuum chamber 50. In the X-ray generating apparatus illustrated in FIG. 3, the current of the electron beams 30 generated from the cathode 52 is controlled by the grid 54, and then, the electron beams 30 is accelerated by the anode 55. In this way, the accelerated electron beams 30 is irradiated onto the anticathode 51 under the condition that the current of the electron beams 30 is controlled appropriately so that the X-ray 20 (of white and non-parallelism) can be generated. Then, the X-ray 20 is taken out of the X-ray transmission window 56, and the X-ray 20 is reflected at the first crystal plate 61 (transmission type) which is made of cubic crystal such as LiF and the reflected X-ray 41 is subsequently reflected by the second crystal plate 62 which is made of any kind of crystal, so that the monochromic X-ray with parallelism is generated. Herein, since the X-ray can be an X-ray with parallelism after the reflection at the first transmission type crystal plate 61. In this embodiment, since the first crystal plate 61 and the second crystal plate 62 are employed, some components with unnecessary wavelength can be removed from the X-ray 20. For example, since the incident angle (α) of the X-ray 20 and the reflective angle (α) of the X-ray 41 at the first crystal plate 61 are the same as the incident angle and the reflective angle at the second crystal plate 62 where the angle between first and second crystal reflection planes is arranged to be 2α, the incident angle of the X-ray 41 to the second crystal plate become α. This means the X-ray 41 can be reflected at the second crystal plate 62, and thus, irradiated onto an object (In FIG. 3, the incident angle and the reflective angle are designated by reference character “α”). However, the X-ray 40 with a different wavelength from the X-ray 41 is incident onto and reflected from the first crystal plate 61 by the angle “β”, and then, incident onto the second crystal plate 62 by the angle “γ”. In this case, since the incident angle “γ” of the X-ray 40 for the second crystal plate 62 is different from the reflective angle “β” for the first crystal plate 61, the X-ray 40 can not be reflected from the second crystal plate 62. In this embodiment, instead of using the first crystal plate 61 is made of cubic crystal such as LiF, the first crystal plate 61 may be formed by combining two crystal plates so that the reflection planes of the crystal plates can be orthogonal to one another. The crystal plates may be made of at least one selected from the group consisting of silicon, lithium fluoride (LiF), graphite, germanium and quartz. Then, a modified X-ray generating apparatus using stationary and the planer target was explained. The same reference numerals are imparted to like components throughout FIGS. 1-4. In this embodiment, the X-ray generator is constructed as the one illustrated in FIG. 3, and only the spectrometer is different from the one illustrated in FIG. 3. In FIG. 3, the spectrometer consists of two type crystal plates, namely, transmission “Laue” type 61 and reflective type 62. In FIG. 4 relating to this embodiment, however, the spectrometer consists of two X-ray transmission type (Laue type) crystal plates 71, 73 and one X-ray surface reflective type crystal plate 72. As illustrated in FIG. 4, these crystal plates are arranged subsequently by the numerical order from the X-ray generator. The reflection plane of the second crystal plate 72 is set almost parallel to the page space so that the X-ray is reflected forward for the page space. The reflection plane of the first crystal plate 71 and the third crystal plate 73 are set almost perpendicular to the page space. Therefore, the reflection plane of the second crystal plate 72 is set almost perpendicular to the reflection plane of the first crystal plate 71 and the third crystal plate 73. The d (111) reflection plane of Si may be applied for the first crystal plate 71 and the second crystal plate 72, and the d′ (200) reflection plane of Si may be applied for the third crystal plate 73. In this case, although the spacing of d and d′ are different from one another, the crystal plates are arranged so that the relations of 2d sin δ=λ and 2d′ sin δ′=λ can satisfied for the different incident angles δ and δ′ which correspond to the first and second crystal plates 71, 72 for the former equation and the third crystal plate 73 for the latter equation, for the X-ray with wavelength λ. In this embodiment, the X-ray 20 (of white and non-parallelism) with a large irradiating area is taken out of the X-ray transmission window 56, and the incident beams travel onto the first crystal plate 71 by the angle δ as shown in FIG. 4, and also by the angle δ downward to the page space, (however this angle is not shown in the figure) so as to set the diffraction plain of the second crystal plane be nearly parallel to the page space. In this case, the X-ray 20 is diffracted in accordance with the Bragg's equation 2d sin δ=λ through the first crystal plate 71. Not demonstrated clearly, if another X-ray with a different wavelength λ′ satisfies the Bragg's equation when the incident X-ray beams travel onto the first crystal plate 71, the X-ray can pass through the first crystal plate 71 after diffraction. In this point of view, even though the X-ray 20 passes through the first crystal plate 71, the X-ray 20 remains the inherent white X-ray with non-parallelism. Since the X-ray 20 with a wavelength λ has a larger irradiating area, the thus obtained X-ray through the first crystal plate 71 has some components parallel to the plane which has an angle of δ from the page space and other components non-parallel to the plane. Since the diffracting direction of the X-ray with a wavelength λ ′ is different from the diffracting direction of the X-ray with the wavelength λ, the X-ray with the wavelength λ′ can not be parallel to the X-ray with the wavelength λ. Then, the X-ray 20 is incident onto the second crystal plate 72 after passing through the first crystal plate 71, and then, reflected forward for the page space. The thus obtained reflected X-ray is incident onto the third crystal plate 73 by an angle of δ′ so that the parallel components of the X-ray can be taken out satisfying the Bragg's equation for the third crystal plate 73. In this way, the monochromatic X-ray 41 with parallelism can be obtained from the white X-ray 20 with non-parallelism. Only if the X-rays with the wavelengths λ and λ′ can be selected by the rotation of the only third crystal plate 73 to satisfy the Bragg's equation, and thus the intended X-ray with parallelism can be obtained from the X-rays. In other words, from a plurality of X-rays with parallelism and respective different wavelengths, aimed monochromatic X-ray with parallelism can be obtained using only the third crystal plate 73 rotation. When the change of the wavelength of the X-rays is very large, the area of the X-ray with parallelism may be decreased. In this case, it can be recovered by the rotationally readjustment of all three crystal plates. Although the present invention was described in detail with reference to the above examples, this invention is not limited to the above disclosure and every kind of variation and modification may be made without departing from the scope of the present invention. Concretely, in the embodiments relating to FIGS. 1-4, a film (coating) may be provided on the surface of the anticathode so as to reduce the evaporation velocity of the electron beam irradiating portion. The film may be made of a material selected from the group consisting of BN, graphite, diamond, Be and alumina Al2O3.
047626461	description	The apparatus of FIG. 1 comprises a number of vessels all formed of or provided with an inner wall of stainless steel such as INOX 314 or 316. A receiving vessel 1 has a hollow wall 2 to receive and circulate coolant liquid such as water. A pipe 3 connects the outlet 4 of the vessel 1 and a holding tank 5, the pipe 3 incorporating a control valve 6. Each of vessels 1 and 5 incorporates a stirring device 7. A pipe 8 leads from the outlet 9 of the tank 6 to the roof 10 of an atomizer dryer 11 of the type known as F10 or P6 available from NIRO Atomizer, France. A vacuum pump 12 is present in the pipe 8. The dryer 11 has an upper portion 13 of constant diameter and a lower portion 14 of conical shape. A rotary turbine 15 extends downwardly from the roof 10 of the dryer 11 and is arranged to rotate at a speed of about 18,000 to 24,000 revolutions/minute. Air is supplied to an electric heater 16 having a capacity of about 140 KW and the heated air is supplied via a pipe 17 to the dryer 11. A pipe 18 leads from the outlet of the dryer 11 to a first filter 19. The filter incorporates filter elements 20. The lower outlet 21 of the filter 19 leads to a fluidized bed 22 and a side outlet 23 leads to a second filter 24 which leads to a ventilator extractor 25. The exit end of the bed 22 leads to heat unit 26 through which pass solid particles and a thermo-hardenable resin below which is a storage area 27. In use, low level radioactive waste liquid is introduced into the vessel 1. A neutralizing agent, such as a solution of potassium hydroxide in water is added while coolant is circulated through the hollow wall 2 and the stirring device 7 is actuated. The pH of the liquid is monitored until a value of between about 6 and about 8, preferably about 6.7 is attained. The neutralized liquid is then passed to the holding tank 2. Air heated by heater 16 is passed via pipe 17 to the dryer 11. The neutralizer liquid is pumped to the rotary turbine 15 which is rotated at about 18,000 to 24,000 r.p.m. to form droplets within the dryer 11 and the heated air atomizes the droplets to form particles and water vapour which deposits as a powder on the inside wall of the dryer 11. The air then passes the powder to the filter 19 to separate water vapour from the particles which are passed over the fluidized bed 22 to the heater 26 to be encapsulated under vacuum and heat in resin. The method is simple to operate and the apparatus is not prone to corrosion. The volume of the liquid is reduced substantially to provide a satisfactory stable end product of high density and low moisture content. The apparatus shown in FIG. 2 is the apparatus of FIG. 1 mounted on a trailer 30 having wheels 31. The trailer may be moved from site to site so that low level radioactive waste may be treated on site. A radiation proof shield 32 covers the exterior of the apparatus. The invention is further illustrated with reference to the following examples. EXAMPLE I Different components which had been subject to a "swimming bath" contamination were decontaminated electrolytically by reaction with a solution formed from a 50/50% by weight mixture of phosphoric acid and sulphuric acid, and then rinsed. A suspension containing 125 g/l of H.sub.2 SO.sub.4, 125 g/l of H.sub.3 PO.sub.4 and 3.3 g/l of metallic ions was collected and was subjected to the process according to the invention in an installation capable of treating approximately 80 l/h of suspension. The suspension was first neutralized to a pH of6.7 by means of a lixiviate at 450 g/l of KOH, while maintaining a temperature below 90.degree. C. A suspension at 438 g/l total salinity was collected, this was then treated in an atomizer equipped with a turbine rotating at 18,000 r.p.m., on the inside of which circulated an output of air of 980 m.sup.3 /h entering at 450.degree. C. and leaving at 110.degree. C. The filtrate was collected off the filters, and about 35 kg/h of particles of 26 micron mean granulometry, 0.57 density and containing less than 0.05% humidity were collected. The content of gaseous waste particles was less than 0.01 mg/Nm.sup.3. These solid particles were mixed with 15 kg of low-density polyethylene of 300 micron granulometry and the mixture placed in polyethylene packings in which was created a relative vacuum of 250 Pa and which were heated to 130.degree. C. The product to be encasked represented 50 dm.sup.3. EXAMPLE II A solution, representative of low level radioactive waste liquid, was made up as follows: ______________________________________ H.sub.3 PO4 686 g/l H.sub.2 SO4 387 g/l Fe 20 g/l Cr 4.75 g/l Ni 2.8 g/l ______________________________________ 100 ml of the solution was diluted with 100 ml of water and to form a mixture which had a pH of about 0.5. The mixture was neutralized with a solution of potash (1.5 potash beads in 4 parts water) to a pH of 6.5. During the course of neutralization a green crystalline precipitate was formed and this was kept in suspension by simple agitation. The neutralized solution was treated using apparatus according to FIG. 1. The heated air entered in the atomiser dryer at 500.degree. C. and exited at 120.degree. C. The turbine was rotated at 20,000 revolutions/minute and the drying time was about 45 minutes. The dryer was opened, and a powdery deposit about 10% humidity was observed on the lower part of the dryer. After drying the moisture content fell to 3%. The sieve analysis showed that 10% of the product was below 14 micron, 50% below 41 micron and 90% below 86 micron. EXAMPLE III The method of Example I was repeated at an inlet temperature of 425.degree. C. and an outlet temperature of 130.degree. C.; the speed of turbine rotation was 24,000 revolutions/minute and the drying took about 2.5 hours. The sieve analysis showed that 10% of the product was below 9 micron, 50% below 30 micron and 90% below 63 micron. The apparatus of the invention may be cleaned out using demineralized water. Because the method of the invention provides a non corrosive form of the radioactive materials and because the inner lining of the vessels is a stainless steel, there is little or no build up of radioactive material in the apparatus so that it will have a long and safe life.
045267430	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will first be described with reference to an embodiment shown in FIG. 1 wherein the reference numeral 10 generally designates a containment vessel of the over-under type (Mark-II type) usually used with a boiling-water type nuclear reactor. The containment vessel 10 comprises a dry well 12 for mounting therein a pressure vessel 11 for containing a nuclear reactor, and a pressure suppressing chamber 14 disposed below the dry well 12 and containing therein a pool of coolant 13. The dry well 12 and the pressure suppressing chamber 14 are separated in airtight relationship by a partition 15 which serves as both a floor of the dry well 12 and a top wall of the pressure suppressing chamber 14. Disposed in the center of the containment vessel 10 and extending vertically through the partition 15 from the bottom of the pressure suppressing chamber 14 to an internal space 17 of the dry well 12 is a pedestal 16 which supports the pressure vessel 11 for containing the nuclear reactor. The portion of the pedestal 16 which is disposed within the pressure suppressing chamber 14 has formed therein an internal space 18 which is maintained, through openings 19 and 20 formed in the pedestal 16 in vertically spaced relationship, in communication with a space 22 formed above a liquid level 21 of the coolant 13 in the pressure suppressing chamber 14 and the pool of coolant 13 respectively. A plurality of downwardly extending vent pipe members 23 and 24 are attached at one end thereof to the partition 15 and arranged in a manner such that the vent pipe members 23 and 24 are disposed annularly about the center line of the pedestal 16 and spaced equidistantly from one another. The vent pipe member 23 and 24 communicate at upper ends thereof with the internal space 17 of the pedestal 16 and include lower end portions which are submerged in the pool of coolant 13 in the pressure suppressing chamber 14. The vent pipe members 23 and 24 are formed at lower ends thereof with exhaust ports 25 and 26 respectively. The submerged lower end portions of the vent pipe members 23, which extend from the liquid level 15 of the coolant 13 to the exhaust ports 25 of the vent pipe members 23 each have a length h.sub.1 which differs from the length h.sub.2 of each of the submerged portions of the vent pipe members 24 which extend from the liquid level 15 to the exhaust ports 26 of the vent pipe members 24. In the embodiment shown and described, h.sub.1 <h.sub.2. The relation between h.sub.1 and h.sub.2 is preferably h.sub.2 =2h.sub.1 for a reason subsequently to be described. Although not shown, spray nozzles may be provided in the internal space 17 of the dry well 12 for ejecting cooling water therefrom for the purpose of spraying water and condensing steam released into the space 17, in the event an accident involving the escape of cooling water in the pressure vessel 11 of the reactor occurs, for example. If this is the case, the internal pressure of the space 17 will become lower than the pressure in the space 22 between the partition 15 and the liquid level 21. In some cases, this phenomenon of lowered pressure in the space 17 may cause the cooling water 13 to be sucked up through the vent pipe members 23 and 24 and at the same time cause the liquid level 15 to be lowered, with the result that the exhaust ports 25 of the vent pipe members 23 having the submerged lower portions of the shorter length will be exposed above the liquid level 21. When such exhaust ports are exposed above the liquid level, the quantity of cooling water 13 sucked up through the vent pipe members 23 will be harled vigorously upon the liquid level 21 as soon as the pressure in the space 17 of the dry well 12 is restored to its normal level. Thus there are possibilities of this phenomenon raising a problem with regard to the safety of the pressure suppressing chamber 14. In order to prevent a reduction of the pressure in the space 17 of the dry well 12 below the pressure in the space 22 between the partition 15 and the liquid level 21, the vent pipe members 23 and 24 are each provided with a known vacuum breaking valve (not shown) for preventing the reduction of the pressure in the space 17 below the pressure in the space 22. In any case, the lengths of the submerged portions of the vent pipe members 23 and 24 are determined such that the exhaust ports 25 of the vent pipe members 23 having the shorter submerged portions are immersed in the pool of cooling water 13, even if the internal pressure of the space 17 of the dry well 12 becomes lower than the pressure in the space 22 in the pressure suppressing chamber 14. More specifically, when the vacuum breaking valves are used, the internal pressure of the space 17 becomes slightly lower than the pressure in the space 22 due to a pressure loss caused by these valves and depending on the pressure at which these valves are set. By taking these facts into consideration, the length h.sub.1 of the submerged portions of the vent pipe members 23 extending from the liquid level 21 to the exhaust ports 25 is determined by using the following formula: EQU h.sub.1 >(.alpha./.gamma.A)(P.sub.2 -P.sub.1) where A is the surface area of the liquid level 21; .alpha. is the total of cross-sectional areas of flow passages through the bores of all the vent pipe members 23 and 24; .gamma. is the specific gravity of the cooling water 13; P.sub.1 is the lowest absolute pressure in the space 17; and P.sub.2 is the absolute pressure in the space 22. The characterizing feature of the present invention is that the vent pipe member 23 and 24 divided into a plurality of groups are arranged such that the vent pipe members of different groups differ from one another in the length of submerged portions of the vent pipe members interposed between the liquid level of the pool of cooling water in the pressure suppressing chamber and the exhaust ports of the vent pipe members. This feature of the invention is based on a study carried out on the pressure transiently applied to the pressure suppressing chamber through the vent pipe members 23 and 24 in the event that an accident involving the escape of cooling water from a nuclear reactor occurs. The results obtained in this study will now be described with reference to FIGS. 2(A) to 2(D). In FIG. 2, there is shown a process in which forces are transiently exerted on the pressure suppressing chamber 14 through vent pipe member 24 in initial stages of the occurrence of an accident involving the escape of a cooling water from the nuclear reactor. The process is shown in chronological sequence in FIGS. 2(A), 2(B), 2(C) and 2(D) in the indicated order. Upon the occurrence of an accident involving the escape of cooling water from the nuclear reactor, air existing in the internal space 17 of the dry well 12 will be forced to pass through the vent pipe member 24 and released into the pool of cooling water 13 through the exhaust port 26 to form an air bubble 27. The internal pressure of the air bubble 27 is equal to a pressure P.sub.D in the internal space 17 of the pressure suppressing chamber 14. The force of the high pressure P.sub.D is exerted on the bottom of the pressure suppressing chamber 14 in the form of a downwardly directed pressure P.sub.L. The air bubble 27 formed in the cooling water 13 begins to float upwardly while expanding [FIG. 2(B)]. This causes the liquid level 21 of the coolant 13 to slightly rise, thereby reducing the volume of the space 22. This results in a gradual increase in an upwardly directed pressure P.sub.U applied to the dry well floor 15. By and by, the air bubble 27 rises to a region of the pool of cooling water 13 near the liquid level 21 while raising the liquid level 21 as shown in FIG. 2(C). At this time, the upwardly directed pressure P.sub.U applied to the dry well floor 15 is maximized in intensity. With the air bubble 27 exploding as shown in FIG. 2(d), the upwardly directed pressure P.sub.U is reduced in intensity. In a conventional containment vessel for a nuclear reactor, there is the disadvantage of forces of high intensity being suddenly exerted on upper and lower walls of the pressure suppressing chamber 14 in initial stages of the occurrence of an accident involving the escape of a cooling liquid from the nuclear reactor, since the vent pipe members are all constructed and arranged such that submerged portions thereof interposed between the liquid level 21 and the exhaust ports of the vent pipe members are equal to one another in length. Let us assume that, in the containment vessel constructed as shown in FIG. 1, all the vent pipe members are of one type and submerged portions thereof extending from the liquid level 21 to the exhaust ports of the vent pipe members have a length h.sub.2 like that of the vent pipe members 24. Then, changes occur in chronological sequence in the total downwardly directed pressure P.sub.L and the total upwardly directed pressure P.sub.U, which are applied to the lower and upper walls of the pressure suppressing chamber 14, as shown in FIG. 3 and FIG. 4 respectively. The total downwardly directed force P.sub.L begins to act in about 0.2 second (T.sub.1) after the occurrence of an accident involving the escape of coolant from a reactor, and the action reaches a highest level in about 0.35 second (T.sub.2). On the other hand, the total upwardly directed force P.sub.U begins to act in about 0.3 second (T.sub.3) and the action reaches a highest level in about 0.65 second (T.sub.4). It has been ascertained that such a sudden increase in the intensity of the total upwardly directed force P.sub.U and the total downwardly directed force P.sub.U has detrimental effects on the safety of the containment vessel of a nuclear reactor. As aforementioned, the vent pipe members according to the invention are divided into a plurality of groups in such a manner that the vent pipe members of different groups differ from one another in the length of portions thereof submerged in the pool of cooling water. In the containment vessel constructed as aforementioned, air to be vented from the internal space 17 of the dry well 12 through the exhaust ports of the vent pipe members in initial stages of an accident involving the escape of coolant from the reactor is first released through the exhaust ports 25 of the vent pipe members 23 of an under-water length h.sub.1. The air is then released, after a slight time lag, through the exhaust ports 26 of the vent pipe members 24 of an under-water length h.sub.2. The total downwardly directed pressure P.sub.L and the total upwardly directed pressure P.sub.U applied to the bottom wall and the top wall respectively are shown in solid line curves in FIGS. 3 and 4. More specifically, release of the air bubbles 27 through the exhaust ports 25 are initiated after a lapse of time T.sub.1 /2 following the occurrence of an accident involving the escape of coolant from the reactor, and the total downwardly directed pressure P.sub.L begins to be applied to the bottom wall of the pressure suppressing chamber 14. The total downwardly directed pressure P.sub.L attains a first maximum value after a lapse of time T.sub.2 /2 following the occurrence of the accident. As the air bubbles 27 released through the exhaust ports 25 begin to expand and float upwardly, the total upwardly directed pressure P.sub.U begins to act after a lapse of time T.sub.3 /2 following the occurrence of the accident, attaining a first maximum value after a lapse of time T.sub.4 /2 following the occurrence of the accident. Release of the air bubbles 27 through the exhaust ports 26 takes place after release of the air bubbles 27 through the exhaust ports 25. That is, owing to the release of air bubbles 27 through the exhaust ports 26, the total downwardly directed force P.sub.L attains a second maximum value after lapse of time T.sub.2 following the occurrence of the accident. After a lapse of time T.sub.4, the total upwardly directed pressure P.sub.U attains a second maximum value. It will be seen that according to the present invention it is possible to markedly reduce the maximum values of the total upwardly directed pressure P.sub.U and the total downwardly directed pressure P.sub.L which are produced in initial stages of the occurrence of an accident involving the escape of coolant from a nuclear reactor, as compared with the corresponding values in the prior art. In the embodiment shown and described above, the vent pipe members are divided into two groups, one group of vent pipe members having an underwater length h.sub.1 and the other group having an underwater length h.sub.2. It is to be understood that the vent pipe members may be divided into three or more groups. It is also to be understood that the ratio of the underwater length of one group to that of another group need not be constant with respect to all the groups. In the embodiment shown and described, time T.sub.4 is about twice time T.sub.2 by virtue of the arrangement that h.sub.2 has a value twice that of h.sub.1. This enables the following unexpected result to be achieved. FIG. 5 shows the behavior of the total upwardly directed force P.sub.U and the total downwardly directed force P.sub.L in relation to the time elapsed after the occurrence of the accident. The net total pressure applied to the pressure suppressing chamber 14 is a pressure equal to the difference between the total upwardly directed pressure and the total downwardly directed pressure. When P.sub.U -P.sub.L <0, pressure is applied downwardly to the pressure suppressing chamber 14; when P.sub.U -P.sub.L >0, pressure is applied upwardly thereto. By arranging that h.sub.1 :h.sub.2 =1:2, it is possible to make the time at which the total downwardly directed pressure P.sub.L attains its second maximum value to substantially coincide with the time at which the total upwardly directed pressure P.sub.U attains its first maximum value. Thus the net pressure applied to the pressure suppressing chamber 14 can be further reduced. The effect of causing the maximum value of the total downwardly directed pressure P.sub.L and the maximum value of the total upwardly directed pressure P.sub.U to cancel each other out, which is achieved by utilizing the fact that T.sub.4 is about twice T.sub.2, can also be achieved when the vent pipe members are divided into three or more groups differing from one another in the length of underwater portions of the pipes. This effect will be described with reference to the case of the vent pipe members being divided into three groups, for example. If the lengths of the underwater portions of three groups of vent pipe members extending from the liquid level 21 to the exhaust ports of the pipes are denoted by h.sub.1, h.sub.2 and h.sub.3 by starting from the shortest length group, the relation, for example, h.sub.1 :h.sub.2 :h.sub.3 =1:2:3 will have to be satisfied in order that the time at which the total upwardly directed pressure attains a maximum value may coincide with the time at which the total downwardly directed pressure attain a maximum value. Generally, when the vent pipe members are divided into m groups in such a manner that the submerged portions of the vent pipe members of different lengths, some of the maximum values of the total downwardly directed pressure P.sub.L and the total upwardly directed pressure P.sub.U can be made to be attained substantially at the same time and consequently to cancel each other out, if h.sub.n, which is the nth length of the underwater portions of the pipes starting from the shortest length group h.sub.1, is determined by using the following equation: EQU h.sub.n =h.sub.1 +(n-1).DELTA.h where .DELTA.h=h.sub.1 when m=2, and .DELTA.h=(h.sub.m -h.sub.1)/(m-1) but .DELTA.h.ltoreq.h.sub.1 when m.gtoreq.3. FIG. 6 shows another embodiment of the invention. Parts shown in FIG. 6 which are similar or equivalent to the parts shown in FIG. 1 are designated by like reference characters and their description will be omitted. Description will only be made of parts in FIG. 6 which differ from the parts shown in FIG. 1. A containment vessel 30 for a nuclear reactor shown in FIG. 6 slightly differs from the containment vessel 10 shown in FIG. 1 in the construction of the pedestal. The pedestal 31 which is installed on the bottom of the pressure suppressing chamber 14 extends through the partition or bottom 15 of the dry well 12 into the internal space 17 of the dry well 12 for supporting the pressure vessel 11 containing a nuclear reactor. There is formed in the pedestal 31 an internal space 32 which is separated from the internal space 17 of the dry well 12 in airtight relationship. The internal space 32 of the pedestal 31 is maintained in communication, through at least one opening 33 formed in the pedestal 31, only with the space 22 in the pressure suppressing chamber 14. Thus no cooling water exists inside the space 32. The pedestal 31 of the embodiment shown in FIG. 6 does without the openings 20 formed in the portion of the pedestal 16 which is immersed in the pool of cooling water 13. By this feature, the strength of pedestal 31 can be increased in a manner such that the strength thereof is about 1.5 times the strength of pedestal 16 shown in FIG. 1. Moreover, since the internal space 32 of the pedestal is entirely maintained in communication with the space 22 in the pressure suppressing chamber 14, the volume of the space 22 can be substantially increased. This enables the maximum value of the total upwardly directed pressure P.sub.U produced in the embodiment shown in FIG. 1 to be lowered as indicated by a dash-and-dot curve as shown in FIG. 7. In the embodiments shown in FIGS. 1 and 6, the vent pipe members have been described as each being formed with an exhaust port disposed at the lower end thereof. It is to be understood, however, that the invention is not limited to this form of exhaust port, and that each vent pipe member 40 may be formed, as shown in FIGS. 8 and 9, with a pair of exhaust ports 41 which are disposed in diametrically opposed positions in a wall of the pipe member. It has been ascertained that the phenomenon shown in FIG. 2 also takes place when each vent pipe members has two exhaust ports as aforesaid. It has also been ascertained that, when the vent pipe members are divided into a plurality of groups differing from one another in the length of submerged portions of the vent pipe members, the total upwardly directed pressure P.sub.U and the total downwardly directed pressure P.sub.L can be made to have a plurality of maximum values of low level in place of a single maximum value of high level as shown in FIGS. 3, 4 and 5, and that it is possible to cause the maximum values of the upwardly directed pressures and the downwardly directed pressures of the different groups of vent pipe members to cancel each other out in case h.sub.n =h.sub.1 +(n-1).DELTA.h as above-mentioned. The vent pipe members of different groups having submerged portions of different lengths are preferably arranged symmetrically with respect to the center line of the pedestal 16 (31) as shown in FIG. 1 (FIG. 6). By this arrangement, it is possible to balance the containment vessel horizontally when the downwardly directed pressures P.sub.L and the upwardly directed pressures P.sub.U are applied to the bottom wall and the top wall respectively of the pressure suppressing chamber 14. The embodiments shown and described above concerns a containment vessel of an over-under type (Mark-II type) for a nuclear reactor. The present invention can also have application in other types of containment vessels including a similar vent pipe device. FIG. 10 to FIG. 13 show an embodiment of the invention as applied to a containment vessel of a lightbulb type (Mark-I type) for a nuclear reactor. As shown, a containment vessel 50 for a nuclear reactor comprises a gourd-shaped dry well 51 having mounted therein a pressure vessel (not shown) containing a nuclear reactor, and an annular pressure suppressing chamber 52 disposed below the dry well 51 and arranged in surrounding relation therewith. The dry well 51 is connected to the annular pressure suppressing chamber 52 through a plurality of vent pipe members 53 each connected at one end to the dry well 51 and extending at the other end portion into the interior of the pressure suppressing chamber 52. An annular ring header 54 is arranged within the annular pressure suppressing chamber 52 and connected to the vent pipe members 53 at the other end of the latter to maintain communication between the ring header 54 and the dry well 51. A plurality of bent pipe downcomers 55 constituting each of the vent pipe members 53 are connected at one end thereof to the ring header 54 and extend downwardly from the ring header 54 into a pool of cooling water 56 contained in the pressure suppressing chamber 52. Each of the vent pipe downcomers 55 is formed at its lower end with an exhaust port 57 which is similar to the exhaust port shown in FIGS. 1 and 6. Each of the vent pipe downcomers 55 may be formed with a pair of exhaust ports disposed in diametrically opposed positions in a wall of the downcomer near its lower end. Thus the interior of the dry well 51 communicates with the pool of cooling water 56 through the vent pipe downcomers 55. The vent pipe members 53 of this embodiment are also divided into a plurality of groups, like those of the embodiments described with reference to FIGS. 1 and 6, in such a manner that the vent pipe downcomers 55 of different groups differ from one another in the length of submerged portions of the downcomers extending from a liquid surface 58 of the cooling water 56 to the exhaust ports 57 of the downcomers 55, in order that the total downwardly directed pressure P.sub.L and the total upwardly directed pressure P.sub.U may have a plurality of maximum values of low level in place of a single maximum value of high level. Preferably, the vent pipe members 53 are divided into m groups so that the submerged portions of the vent pipe downcomers 55 may have different lengths which are m in number, and the length h.sub.n of the submerged portions of the downcomers 55 which belong to the nth group starting from the shortest submerged length h.sub.1 group is determined by using the following equation: EQU h.sub.n =h.sub.1 +(n-1).DELTA.h where .DELTA.h=h.sub.1 when m=2, and .DELTA.h=(h.sub.m -h.sub.1)/(m-1) but .DELTA.h.ltoreq.h.sub.1 when m.gtoreq.3. By dividing the downcomers 55 into a plurality of groups differing from one another in the length of submerged portions thereof, it is possible to cause the maximum values of the upwardly directed pressures and the downwardly directed pressures to cancel each other out, in the same manner as described with reference to the embodiments shown in FIGS. 1 and 6. Consequently, this arrangement makes it possible to suppress impact which would otherwise be applied to the pressure suppressing chamber 52 by air bubbles formed in the pool of cooling water 56 by non-condensable gas which passes from the dry well 51 through the vent pipe downcomers 55 in initial stages of occurrence of an accident involving the escape of coolant from the nuclear reactor, thereby enhancing the safety of the containment vessel 50 for a nuclear reactor.
	abstract	Systems join with a control rod drive and expand or contract to displace elements necessary for decoupling. Joining structures affix to on sides of the control rod drive allow discriminatory jacking by a powered drive also in contact with the control rod drive. A moveable piston tube can be displaced by this jacking with hundreds or thousands of pounds of force with respect to the control rod drive. Probes and other instrumentation and sensors are useable in the systems to accurately measure any of piston tube displacement, temperature, malfunction; drive power status, displacement or speed; and communications status. Manual interaction with the systems are not required during the jacking, and installation and removal of the systems requires no tools or great amount of time or effort. Through remote operation and brief installation, human exposure to radiation about control rod drives is minimized.
	description	The embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) In an image acquisition apparatus according to the first embodiment of the present invention, when an acquired image is to be reproduced, the problem in the prior art is solved by setting the intervals of grid lead members such that even if a grid image exists and interferes with an image component to a certain degree, the produced stripes have a frequency which hardly makes an observer have a sense of incongruity. This embodiment will be described below. In digital images obtained by sampling, image artifacts produced by the grid are classified into the following two categories: (A) grid images having low spatial frequencies; and (B) beat images obtained by sampling grid images having low spatial frequencies. FIGS. 7(1-a) to 7(3-b) schematically show the states of artifacts to explain artifacts belonging to categories (A) and (B). For the sake of descriptive convenience, consider only a fundamental wavelength, assuming that the second- and higher-order harmonics of a grid stripe pattern are not resolved. FIG. 7 (1-a) shows the state of an artifact belonging to category (A) in the frequency domain (only the positive region). Reference numeral 61 denotes an image component region, which exhibits a substantially maximum frequency fi; and 62, an image harmonic component mathematically produced by sampling. In this case, a sampling frequency is represented by fs, and Nyquist frequency fnq=fs/2. A line spectrum 63 is a grid stripe pattern component having a frequency fg. As shown in FIG. 7(1-a), since this component overlaps the image component 61 to impair the image quality, and has a low frequency, the observer experiences a sense of incongruity from the stripe pattern. FIG. 7(1-b) one-dimensionally shows how sampling is performed. In FIG. (1-b), xe2x80x9cxe2x97xafxe2x80x9d (bullet) indicates a sampling point. It is obvious from the above description that the frequency fg of the grid stripe pattern and the frequency fi (fi less than fs/2) of the image must satisfy: fg greater than ixe2x80x83xe2x80x83(1) FIG. 7(2-a) shows the state of another artifact belonging to category (A) in the frequency domain (only in the positive region). A region 61 is an image component region and exhibits the maximum frequency fi. Since the frequency fg of the grid is higher than the Nyquist frequency fnq that is xc2xd the sampling frequency fs, a frequency component 64 of fsxe2x88x92fg, which is aliasing, appears. In the case shown in FIG. 7(2-a), the frequency component 64 as aliasing overlaps the image component 61 and impairs the image quality, and hence a stripe pattern gives the observer a sense of incongruity. FIG. 7(2-b) one-dimensionally shows how sampling is performed. In FIG. (2-b), xe2x80x9cxe2x97xafxe2x80x9d (bullet) indicates a sampling point, and the dashed line indicates a signal form before sampling. That is, to prevent impairment of the image component, the frequency fg of the grid stripe pattern and the frequency fi (fi less than fs/2) of the image must satisfy: fsxe2x88x92fg greater than fixe2x80x83xe2x80x83(2) According to inequalities (1) and (2), the frequency fg of the grid stripe pattern must satisfy the following inequality, in relation to the maximum frequency fi of the image and the sampling frequency fs: fi less than fg less than fsxe2x88x92fi(fi less than fs/2)xe2x80x83xe2x80x83(3) In this case as well, an artifact belonging to category (B) may be produced. FIG. 7(3-a) shows a state of an artifact when the grid stripe pattern frequency is set in the spatial frequency region which satisfies inequality (3). FIG. 7(3-b) one-dimensionally shows how sampling is performed. In FIG. (3-b), xe2x80x9cxe2x97xafxe2x80x9d (bullet) indicates a sampling point, and the dashed line indicates a signal form before sampling. Referring to FIG. 7(3-a), it seems that since an image frequency component 61 does not overlap a grid image component 63, the image is not impaired, and the observer has no sense of incongruity. If, however, beat noise-like amplitude variation component overlaps a frequency component of image information as shown in FIG. 7 (3-b), the observer of the image recognizes this overlap as an artifact, and a stripe pattern gives the observer a sense of incongruity. The frequency of this amplitude variation is given by ↑fs/2xe2x88x92fg\|. When some nonlinear conversion is performed for the image, this variation component may actually become an artifact that impairs the image. If, for example, the frequency of a grid stripe pattern on an image is set in a frequency region where beat-like artifacts (moire) occur (i.e., a high-frequency region), the grid stripe pattern and beat-like artifacts may be removed by filtering without damaging the image information (e.g., filtering to remove only components near the spatial frequency of the grid stripe pattern). If, however, nonlinear element conversion (e.g., logarithmic conversion) is performed for a low-frequency beat-like artifact, the artifact becomes a signal component having an actual spectrum. In this case, this artifact cannot be removed by the above filtering technique. A beat-like artifact is repetitions of high-amplitude and low-(or zero-)amplitude portions of a stripe pattern. Since a high-amplitude portion inevitably differs in noise characteristics from a low-amplitude portion, even if stripe components are removed, variations in noise characteristics remain. As described above, even if the frequency of a grid stripe pattern on an image is set in a frequency region where beat-like artifacts occur, and the grid stripe pattern is removed by filtering, some kind of mark of a beat-like artifact may remain. Therefore, the beat-like artifact itself (the occurrence or magnitude of the beat-like artifact) should be suppressed. Ideally, all artifact frequencies should fall outside the frequency fi of the image. In this case, no problem arises. Although the frequency fi is the maximum frequency of the image, this frequency may be regarded as a frequency that gives the observer no sense of incongruity when the image is reproduced (hard copy, monitor display, or the like). Both inequality (3) and \|fs/2xe2x88x92fg\| greater than fi must be satisfied at once. Assuming that fg is set at a position corresponding to fs greater than fg greater than fs/2, the following inequality is established: fi+fs/2 less than fg less than fsxe2x88x92fixe2x80x83xe2x80x83(4) To satisfy this inequality, fi less than fs/4 must also be satisfied, which is a strict condition. If fi less than fs/4 is not satisfied in inequality (4), there is no overlap between the ranges defined by the left- and right-side signs. That is, an ideal condition for eliminating the influences of the grid is that the frequency band of the image is equal to or less than xc2xd the Nyquist frequency, and the frequency of the grid stripe pattern is near xc2xd the Nyquist frequency. This condition means that if an image to be acquired is determined, the sampling frequency must be set to at least four times higher than the maximum spatial frequency of the image to be acquired. No consideration, however, is given to the power of beat noise-like variation component. The present inventor has contrived and proven that the condition given by inequality (4) can be moderated, on the basis of the result obtained by comparing the power of the beat noise-like variation component with the power of the grid stripe pattern and the result obtained by observing the image actually formed by using the grid. As the frequency of the stripe pattern separates farther from the Nyquist frequency, the amplitude variation as beat noise increases in frequency. As a consequence, this component cannot be observed. Consider how much this stripe pattern frequency differs from the Nyquist frequency when it becomes difficult for the observer to observe the variation component. Line spectra always exist at positions which have a mirror-image relationship centering on the Nyquist frequency whenever sampling is performed, and beat noise is always produced between them. In the cases shown in FIGS. 7(1-b) and 7(2-b), although beat noise is produced, it does not exist apparently. One conceivable reason for this is attributed to frequency; in the case shown in FIG. 7(2-a) or 7(3-a), the distance (frequency) between the two spectra having a mirror-image relationship centering on the Nyquist frequency is large, and hence the beat noise frequency becomes high. At this time, the spectrum of the fundamental sine wave exists sufficiently below the Nyquist frequency, and they greatly differ in frequency and power. For this reason, only the fundamental sine wave having stronger power is strongly recognized by the observer. The manner in which beat noise is produced is mathematically expressed. Consider a case wherein a sine wave having the spatial frequency fg is sampled at the sampling frequency fs. Assume that fg greater than fs/2 is set in consideration of the grid actually used. This is not a necessary condition. In this case, as shown in FIG. 8A, a line spectrum pair corresponding to the frequency of the sine wave is produced. Let a/2 be the peak of each line spectrum, and axc3x97cos(2xcfx80fqx) be the initial grid image. When a cosine wave having the frequency fg is sampled at the frequency fs, two cosine waves appear below fs. g(x)=a{cos(2xcfx80fgx)+cos(2xcfx80(fsxe2x88x92fg)x)}=2axc3x97cos(2xcfx80(fgxe2x88x92fs/2)x)xc3x97cos(2xcfx80sx/2)xe2x80x83xe2x80x83(5) Equation (5) represents beat noise, which is equivalent to the amplitude modulated by a sine wave having a frequency corresponding to the difference between the two sine waves. As (fg/2xe2x88x92fs) becomes a small value other than 0, an unstable amplitude variation (beat) with a low frequency occurs. According to the Shannon""s sampling theorem, data sampled at a frequency equal to or lower than the Nyquist frequency can be completely reconstructed by using an ideal filtering means (a filter that passes signals having frequencies equal to or lower than the Nyquist frequency), and no beat is produced by the line spectrum pair. It is likely that the observer strongly recognizes the beat noise in the case shown in FIG. 7(3-b) because of the filtering means. In general, a sampled signal is reconstructed by connecting the sampling points with a straight line or the like. This means differs from an ideal filtering means according to the sampling theorem. A person with normal visual perception or display apparatus interpolates by connecting neighboring points with a straight line without using any ideal filter (convolution using a sinc function as a kernel) as in the sampling theorem. The same applies to a case wherein a signal is observed as an image. That is, such a difference between normal visual perception and the sampling theorem appears as beat noise. Interpolating with a straight line amounts to filtering with a characteristic like a characteristic curve 71 in FIG. 8B. According to the characteristic curve 71 in FIG. 8B, a form s(f) of the filter is given by s(f)=sin2(xcfx80f/fs)/(xcfx80f/fs)2xe2x80x83xe2x80x83(6) Let c/2 and d/2 be the heights of a line spectrum pair at mirror-image positions after filtering. The sum of sine waves at this time is expressed like equation (5): g ⁡ ( x ) = ⁢ d xc3x97 cos ⁡ ( 2 ⁢ π ⁢ xe2x80x83 ⁢ fgx ) + c xc3x97 cos ⁡ ( 2 ⁢ π ⁡ ( fs - fg ) ⁢ x ) = ⁢ 2 ⁢ d xc3x97 cos ⁡ ( 2 ⁢ π ⁡ ( fg / 2 - fs ) ⁢ x ) xc3x97 cos ⁡ ( 2 ⁢ π ⁢ xe2x80x83 ⁢ fsx / 2 ) + ⁢ ( c - d ) xc3x97 cos ⁡ ( 2 ⁢ π ⁡ ( fs - fg ) ⁢ x ) ( 7 ) The first term of equation (7) represents beat component; and the second term, a general sine wave component. According to equation (5), we have c / 2 = ( a / 2 ) ⁢ sin 2 ⁡ ( π ⁢ xe2x80x83 ⁢ fs - fg fs ) ( π ⁢ xe2x80x83 ⁢ fs - fg fs ) 2 , d / 2 = ( a / 2 ) ⁢ sin 2 ⁡ ( π ⁢ xe2x80x83 ⁢ fg fs ) ( π ⁢ xe2x80x83 ⁢ fg fs ) 2 ⁢ ( fg greater than fs ) ( 8 ) If in equation (7) the power of the second term which represents the normal sine wave component exceeds the power of the first term which represents the beat component, it may become difficult for the observer to recognize the beat component. If the ratio of the power of the first term to that of the second term in equation (7) is calculated on the basis of the above assumption, then (cxe2x88x92d)2/2d2 greater than 1 (condition under which the power of the second terminal exceeds that of the first term) This inequality can be rewritten into c/d greater than 21/2+1 A substitution of this into equation (7) yields ⁢ sin 2 ⁡ ( π ⁢ xe2x80x83 ⁢ fs - fg fs ) ( π ⁢ xe2x80x83 ⁢ fs - fg fs ) 2 sin 2 ⁡ ( π ⁢ xe2x80x83 ⁢ fg fs ) ( π ⁢ xe2x80x83 ⁢ fg fs ) 2 greater than 2 + 1 , fg fs - fg greater than 2 + 1 , fg greater than fs 1 2 + 1 + 1 ⁢ fg greater than 0.608 ⁢ xe2x80x83 ⁢ fs ( 9 ) It is obvious from inequality (9) that if the frequency of a sine wave to be sampled is higher than 60.8% of a sampling frequency (aliasing occurs), sampling can be performed with little observable beat noise. In this case, grid stripe pattern information appears as a component equal to or less than 80% of the Nyquist frequency (fs/2). This component is equivalent to a component equal to or less than 40% of the sampling frequency. If, therefore, the grid stripe pattern has a frequency equal to or less than 80% of the Nyquist frequency, a stable stripe pattern can be observed without any conspicuous beat upon sampling. The above consideration defines the upper limit spatial frequency of a stripe pattern (grid stripe pattern) appearing below the Nyquist frequency due to the grid. More specifically, the frequency of the grid stripe pattern is set to be equal to or less than 80% (equal to or less than 40% of the sampling frequency) of the Nyquist frequency. In practice, however, this frequency has its own lower limit. Since an artifact originating from the stripe pattern itself, i.e., stripe pattern information, is not allowed to overlap an image component, the maximum frequency of the image component needs to be lower than the lower limit frequency of the grid stripe pattern. In general, the maximum frequency component of a signal representing an image cannot be accurately defined. Examples of evaluation criteria for images will be listed below: A frequency that meets the approval of the observer when an acquired image is reproduced by a display apparatus or recording apparatus. When a maximum frequency is assumed, the sampling pitch is determined by regarding 1.5 to 2 times the assumed frequency as a maximum frequency (see Nakamizo et al., xe2x80x9cCounting/Measurementxe2x80x9d (Baihukan)). The latter condition is widely used, in particular, and the sampling pitch is often set such that a spatial frequency required generally is equal to or less than 60% of the Nyquist frequency (equal to or less than 30% of the sampling frequency). That is, the sampling pitch is set such that grid stripe pattern information appears at a frequency equal to or higher than the sampling frequency. Note that the lower limit of grid stripe frequencies is 25% the sampling frequency with reference to xe2x80x9c2 timesxe2x80x9d of xe2x80x9c1.5 to 2 timesxe2x80x9d described above and ⅓ the sampling frequency with reference to xe2x80x9c1.5 timesxe2x80x9d thereof. Therefore, the lower limit of grid stripe frequencies may be set to at least 25% of the sampling frequency, preferably 30% thereof, more preferably ⅓ thereof. Assume that the sampling pitch is 0.1 mm (fs=10 cyc/mm). In this case, the Nyquist frequency is 5 cyc/mm. According to the above general condition, the frequency of an image component which is generally used is equal to or less than 30% of the sampling frequency, i.e., 3 cyc/mm. That is, the lower limit frequency of stripe pattern information is 3 cyc/mm, and the upper limit frequency is 40% of the sampling frequency, i.e., 4 cyc/mm. If, therefore, the frequency of a grid stripe pattern is set within the range of 3 to 4 cyc/mm, no conspicuous beat appears in a grid stripe pattern and interferes with observation. The above condition is set to determine the frequency of a grid stripe pattern, and the frequency of the lead members of the grid body whose stripe pattern corresponds to this value changes after sampling. In this case, as shown in FIG. 9 a frequency range RG [cyc/mm] of the grid body is given by 5(2n+1)xe2x88x922xcx9c5(2n+1)xe2x88x921 or 5(2n+1)+1xcx9c(2n+1)+2; n=0, 1, 2, . . . (see FIG. 9) where n is an integer equal to or more than 0. This mathematical expression represents a value calculated when the sampling pitch is 0.1 mm (fs=10 cyc/mm) In general, if the sampling frequency fs [cyc/mm] is (sampling pitch 1/fs [mm]), the frequency range of the grid body is given by fs(n+0.3)xcx9cfs(n+0.4) or fs(n+0.6)xcx9cfs(n+0.8)[cyc/mm] The frequency of the grid body (the number of grid elements) is determined within the above range in consideration of scattered ray removing performance as the primary object of the grid, the resolution of a flat panel sensor, and the like. In general, in consideration of the resolution of the sensor, a grid stripe pattern frequency of 6 to 7 cyc/mm can be selected, at which the second-order harmonic is difficult to resolve and the scattered ray removing ratio is high. In this embodiment, the frequency of the grid to be used is selected by the above calculation such that the observer can be satisfied to some degree without removing any grid stripe pattern information owing to some experience or depending on an application purpose, thus overcoming the problem. As the spatial frequency of the grid stripe pattern is fixed, the grid stripe pattern information can be removed to some extent by filtering. In removing the grid stripe pattern information by setting a grid stripe pattern frequency in the above manner, even if the pattern information cannot be completely removed, reducing the intensity of the grid stripe pattern will minimize the influence on the observer. FIG. 1 is a schematic view of the first embodiment. FIG. 1 shows a system for imaging the human body lying on a table. Reference numeral 1 denotes an X-ray tube; 2, a human body as an object to be imaged; 11, a grid for removing scattered X-rays, which is a detachable grid for removing scattered X-rays from the object 2; 3, an X-ray sensor panel for converting an X-ray intensity distribution (X-ray transmission distribution) into a charge distribution, two-dimensionally sampling the distribution at desired intervals, and sequentially outputting the sampled data; 5, an analog/digital converter; 4, a controller for controlling the X-ray radiation timing and image acquisition timing; and 6, a memory for temporarily storing an image. The X-ray sensor panel 3 varies in offset and gain for each pixel. To correct this variation, an offset value as an image acquired without any radiation of X-rays is stored in a memory 8, whereas data obtained by logarithmically converting a gain value acquired without the object 2 and grid 11 is stored in a memory 9. Reference numeral 7 denotes a conversion unit for logarithmic conversion, and more specifically, a lookup table. An acquired image of the human body is logarithmically converted after the offset value in the memory 8 is subtracted (removed) from the image. The difference between the resultant value and the gain value in the memory 9 is calculated (division) to obtain an X-ray intensity distribution image having undergone correction of a variation in gain value. This image is temporarily stored in a memory 10. Thereafter, the stored image is extracted and subjected to image storage, image processing, image display, and hardcopy operation, and the like to be used for diagnosis and the like. A block 12 is an image processing means (filtering means) for removing grid stripe pattern information by image processing (filtering). The image processing means 12 removes a grid stripe pattern component by spatial filtering using the image stored in the memory 10. A mechanism 13 is a selection means (switch) that is operated by the operator to choose between using the filtering means 12 or not using it in accordance with an output from an external output from a grid removing operation effective setting means (mechanism) 16 or operation panel 20. The flow of a signal can be changed to skip the operation of the block 12 in accordance with the selection made through the selection means 13. In this case, the X-ray sensor panel 3 has a plurality of pixels distributed vertically and horizontally at a pitch of 0.1 mm in a two-dimensional space. With this structure, two-dimensional, discrete sampling is performed. As described in relation to the setting of the above grid stripe pattern frequency, the grid stripe pattern frequency (the number of grid elements) of the grid 11 is set to 6 to 7 cyc/mm, and hence the observer can observe an image without a sense of incongruity even if the grid stripe pattern information is not removed by filtering. FIG. 2A schematically shows the state of a one-dimensional amplitude spectrum in a direction perpendicular to the grid stripe pattern of the image stored in the memory 10. Referring to FIG. 2A, reference numeral 32 denotes a spectrum of an image component; and 31, a spectrum of a grid stripe pattern component, which exhibits a substantial spectrum form with noise being neglected. Even if the grid stripe pattern component 31 exists, the observer observes only this stable frequency component, and there is no component associated with beat noise. Therefore, as the observer becomes accustomed to the stripe pattern or recognizes it, the existence of the stripe pattern does not relatively interfere with the observation. If, however, the operator or observer wants to remove the grid stripe pattern information from this image owing to subsequent image processing or the image reproducing mechanism, he/she selects grid removing operation through the operation panel 20. FIG. 2B schematically shows the state of a spectrum upon execution of grid removing filtering. Reference numeral 33 denotes an example of a filter characteristic; and 34, an image spectrum after filtering. To stabilize spatial characteristics, the filter cannot have a steep characteristic. If, therefore, the grid stripe pattern component 31 is removed, part of an image component inevitably deteriorates in response characteristic. In consideration of this, the operator chooses between removal and nonremoval of the grid. In this embodiment, when the acquired image exhibits the gain value stored in the memory 9, no problem arises if the image is acquired without removing the grid 11 because the frequency of the grid is constant. FIG. 3 is a flow chart for the implementation of this embodiment by means of software. Referring to FIG. 3, a process block (step) is divided into operations in blocks C1 to C11. The operation in block C1 is executed to acquire an image of a gain value. An image A is obtained by radiating X-rays without any object. In block C2, this image is logarithmically converted into an image B. In block C3, an offset value is obtained; an image C is obtained without radiating any X-rays. In block C4, an image of the object is actually acquired; the grid is installed, and an image D is obtained by irradiating the object with X-rays. In block C5, the image C is subtracted from the image D to obtain an image E having undergone offset correction. In block C6, the image E is logarithmically converted into an image F. In block C7, the image B is subtracted from the image F to obtain an object image G having undergone gain correction. In block C8, the flow branches depending on whether a stripe pattern operating from grid will be removed in accordance with operation (instruction) of the operation panel 20 by the operator. In block C9, since the instruction to remove the grid is received, filtering, i.e., grid removing operation, is performed for the image G to obtain an object image H from which grid stripe pattern information is removed. In block C10, the object image H is output. If no grid removing instruction is received, the object image G is output without any processing in block c11. In this embodiment, as the memory means 10 in FIG. 1, a nonvolatile storage medium such as a magnetic disk may be used to always store image data including grid stripe pattern information to allow the operator to select an image without any grid stripe pattern information or an image with grid stripe pattern information or output them at once. Furthermore, this embodiment can be practiced with an arrangement including only an image storage system without any image acquisition system. (Second Embodiment) FIG. 4 is a block diagram showing the second embodiment, in which the frequency of a grid stripe pattern, the sampling pitch of an X-ray sensor panel, and the like are set in the same manner as in FIG. 1. In the structure shown in FIG. 4, an application purpose table 14 is prepared. After an image is acquired, the operator selects an application purpose through an application purpose setting means 17 with respect to the image stored in a memory 10 or magnetic disk. As a consequence, whether to remove the grid or not is automatically selected. If a switch 13 selects the A side, the image in the memory 10 is filtered by a filtering unit 12 and output. If the switch 13 selects the B side, the image in the memory 10 is output without being filtered. As described in relation to the setting of the above grid stripe pattern frequency, the grid stripe pattern frequency (the number of grid elements) of a grid 11 is set to 6 to 7 cyc/mm, and hence the observer can observe an image without a sense of incongruity even if the grid stripe pattern information is not removed by filtering. With this table 14, for example, in emphasizing a high spatial frequency as in spatial frequency emphasis processing, since a grid image becomes a hindrance, it is removed (the switch 13 is set on the A side). In displaying an image or performing hardcopy operation on a larger scale, i.e., 100% or more, the switch 13 is set on the B side to inhibit removal of a grid image so as to minimize an image blur. In displaying an image or performing hardcopy operation upon reduction, the switch 13 is set on the A side to remove a grid image. If an image is to be stored in another storage means, since removal processing can be performed for the stored image, the switch 13 is set on the B side to inhibit removal of a grid image, thus increasing the information amount. (Third Embodiment) FIG. 5 is a block diagram showing the third embodiment, in which the frequency of a grid stripe pattern, the sampling pitch of an X-ray sensor panel, and the like are set in the same manner as in FIG. 1. In the structure shown in FIG. 5, an imaging position table 18 is prepared. When the operator selects an application purpose through an imaging position setting means 19 with respect to the image stored in a memory 10 or magnetic dick upon imaging operation, whether to perform grid removing operation or not is automatically selected. As described in relation to the setting of the above grid stripe pattern frequency, the grid stripe pattern frequency (the number of grid elements) of a grid 11 is set to 6 to 7 cyc/mm, and hence the observer can observe an image without a sense of incongruity even if the grid stripe pattern information is not removed by filtering. With this table 18, when the observer is to observe an image of a bone portion such as the pelvis or joint, which requires a high spatial frequency for the image, a switch 13 is set on the B side to allow the observer to observe the image without any blur without removing a grid image. When the observer is to observe a chest portion (front chest portion), abdomen, or the like for which a high spatial frequency is not required, and a halftone image needs to be easily observed, the switch 13 is set on the A side to allow the observer to observe the image without any grid image. (Fourth Embodiment) Although the grid frequency is so set that a grid image does not relatively interfere with observation, if the contrast of the grid image is strong, it still interferes with the observer. The contrast of a grid image varies depending on the conditions (e.g., energy) of X-rays to be used. In some case, an object is imaged without any grid. To determine this, the spectrum of a given portion of an acquired image in a direction perpendicular to the grid is calculated, and whether to perform grid removing operation or not is selected depending on the peak value of the grid component (directly corresponding to the contrast value if it is a logarithmic image). FIG. 6 is a block diagram showing the fourth embodiment, in which the frequency of a grid stripe pattern, the sampling pitch of an X-ray sensor panel, and the like are set in the same manner as in FIG. 1. As described in relation to the setting of the above grid stripe pattern frequency, the grid stripe pattern frequency (the number of grid elements) of a grid 11 is set to 6 to 7 cyc/mm, and hence the observer can observe an image without a sense of incongruity even if the grid stripe pattern information is not removed by filtering. A block 15 in FIG. 6 includes software; a flow chart is shown in the block. In block C21 in the flow chart, an arbitrary line is acquired from an image from a memory 10. In block C22, one-dimensional Fourier transformation is performed for this image to calculate an amplitude spectrum. In block C23, an amplitude value (spectrum value) Vp corresponding to the grid frequency is measured from the amplitude spectrum value. In block C24, the amplitude value Vp is compared with a threshold TH set in advance. If Vp is larger than TH, the corresponding grid image must be removed. To remove the grid image, therefore, a switch 13 is set on the A side in block C25. If Vp is not larger than TH, the switch 13 is set on the B side in block C26. Note that the switch 13 may be selectively operated in accordance with the magnitude of contrast of a grid stripe pattern existing at the grid frequency. If the contrast is higher than a predetermined threshold, the switch 13 is set on the A side to remove a grid image. If the contrast is lower than the predetermined threshold, the switch 13 is set on the B side to inhibit the removal of a grid image. As described above, according to this embodiment, in a system for two-dimensionally sampling an X-ray image and forming a digital image, an image that can be observed by the observer with little sense of incongruity without removing a grid stripe pattern from the image can be formed by setting the frequency of the grid lead members to be equal to or lower than 40% of the sampling frequency at which the spatial frequency of a stripe image originating from the grid for removing scattered rays from the image and equal to or higher than the frequency (60% of the Nyquist frequency in general) at which a grid image does not easily interfere with observation of the image by the observer and does not overlap an image component. In addition, the filtering means 12 can choose between removal or nonremoval of a grid stripe pattern in accordance with selection through the switch 13. Since a grid stripe pattern is automatically removed in accordance with operation by the operator (observer), the application purpose of an image, imaging position, and the amplitude (intensity) of a grid stripe pattern, an appropriate image can be obtained by removing a grid stripe pattern only when required. Each embodiment described above is merely an example in practicing the present invention. Note that the technical scope of the present invention should not be interpreted in a limited manner. That is, the present invention can be practiced in various forms without departing from the spirit and scope of the present invention. As has been described above, according to each embodiment described above, when an X-ray image is two-dimensionally sampled to acquire a digital image, an image that can be observed by the observer with little sense of incongruity without removing a grid stripe pattern from the image can be formed by setting the spatial frequency of a stripe pattern originating from the grid for removing scattered rays from the image to a predetermined value. In addition, since whether to remove a stripe pattern originating from the scattered ray removing grid from an image can be selected, an appropriate image can be obtained by removing a stripe pattern originating from the scattered ray removing grid. (Fifth Embodiment) In the above case, since the resolving power of the X-ray image receiving unit (X-ray image sensor) is not very high, the above apparatus is based on the premise that the grid pattern exhibits an almost single sine wave. This will be described below. Recently, with technical innovation of X-ray image sensors, a scheme of directly converting an X-ray intensity distribution into a charge distribution by using, for example, a method of acquiring free electrons, generated by X-rays, using a strong electric field, has been studied and put into practice, in place of an indirect conversion scheme of converting an X-ray intensity distribution into a fluorescence distribution first and then photoelectrically converting the fluorescence distribution. In the case of the direct conversion scheme, an aperture used to acquire X-rays as charges (electrons) is the main factor that determines resolving power, and hence a high-resolving power X-ray image sensor can be obtained. When such a high-resolving power X-ray image sensor is used, an original grid pattern is resolved more finely (harmonic components are also resolved) regardless whether the sensor is not based on the direct conversion scheme. It is therefore expected that a grid pattern in an acquired image may not exhibit a single sine wave. Such a situation will be described with reference to FIG. 15. FIG. 15 is a graph on a one-dimensional spatial frequency axis, with the abscissa representing the spatial frequency. Referring to FIG. 15, a Nyquist frequency Fn in the middle is a Nyquist frequency set when the pixels of the sensor are regarded as pixels corresponding to spatial sampling, i.e., xc2xd a sampling frequency (the reciprocal of the sampling pitch) Fs. The peak denoted by reference numeral 201 in FIG. 15 is the spatial frequency of the lead foil members of the grid, which is set to Fg=1.25 Fn, for the sake of convenience. According to the sampling theorem, this frequency is expressed by a frequency equal to or lower than the Nyquist frequency, and the frequency Fm1 can be calculated as follows: Fm1=2xc2x7Fnxe2x88x92Fg=0.75Fnxe2x80x83xe2x80x83(10) This peak is denoted by reference numeral 202 in FIG. 15. If the resolving power of the sensor in use is high, a second-order harmonic 2Fg of a grid frequency Fg is sampled at the same time. A frequency Fm2 of this harmonic is calculated as follows and is denoted by reference numeral 203 in FIG. 15: Fm2=2xc2x7Fgxe2x88x922xc2x7Fn=0.5Fnxe2x80x83xe2x80x83(11) A third-order harmonic Fm3 is denoted by reference numeral 204 in FIG. 15 and given by Fm3=4xc2x7Fnxe2x88x923xc2x7Fg=0.25Fnxe2x80x83xe2x80x83(12) In general, a frequency Fk on an image with respect to k-th order harmonic is expressed by Fk=\|2xc2x7jxc2x7Fnxe2x88x92kxc2x7Fg\|xe2x80x83xe2x80x83(13) (An integer j including 0 is selected to satisfy 0xe2x89xa6Fkxe2x89xa6Fn.) As described above, when a high-resolving power sensor is used, even line spectra originating from such harmonics appear as stripe pattern information on an image. According to the conventional technique, in order to remove such stripe pattern information originating from a plurality of spatial frequencies from an image, filtering corresponding to each frequency must be done. This inevitably affects image information. The following embodiment has been made in consideration of the above problems and explains a radiation imaging method and apparatus which facilitate removing or reducing components originating from a grid in an acquired image or can acquire an image that is easy to observe even in the presence of such components, and a design method for the apparatus. In addition, the following embodiment explains a radiation imaging method and apparatus which facilitate removing or reducing harmonic components originating from a grid in an acquired image or can acquire an image that is easy to observe even in the presence of such components, and a design method for the apparatus. The following embodiment explains a radiation imaging method and apparatus which can integrate a fundamental frequency component and second-order harmonic component originating from a grid in an acquired image into a substantially single spectrum, and a design method for the apparatus. Furthermore, the following embodiment explains a radiation imaging method and apparatus which can integrate components originating from a grid in an acquired image into a substantially single spectrum, and a design method for the apparatus. Other objects of the following embodiment will be obvious from the following description of the specification. According to the following embodiment, image components originating from a grid in an acquired (visualized) image are integrated (converged) in a substantially single spectrum. The fifth embodiment will be described below with reference to the accompanying drawings. The fifth embodiment exemplifies an arrangement for converging grid stripe spectra up to at least the second-order harmonic into a substantially single spatial frequency spectrum by spatial sampling. This arrangement makes a grid stripe pattern (an image component originating from the grid) become an approximate sine wave form and prevent the occurrence of unnecessary low-frequency components. In addition, a grid pattern can be easily or properly removed, as needed, by grid pattern removal processing with subsequent filtering operation or the like. Conditions under which the fundamental frequency (k=1) of a grid pattern component coincides with the frequency (k=2) of the second-order harmonic component in a sampled image are calculating by referring to equation (13). Since this is an absolute value computation, the following two conditions will be considered. { 2 ⁢ j 1 ⁢ F n - F g = 2 ⁢ j 2 ⁢ F n - 2 ⁢ F g xe2x80x83 ⁢ ( ⁢ 14 ⁢ - ⁢ 1 ⁢ ) 2 ⁢ j 1 ⁢ F n - F g = 2 ⁢ F g - 2 ⁢ J 2 ⁢ F n xe2x80x83 ⁢ ( ⁢ 14 ⁢ - ⁢ 2 ⁢ ) "AutoRightMatch" where j1 and j2 are positive integers (natural numbers) including 0. By solving equation (14-1) for Fg, the following equation is obtained: Fg=2Fn(j2xe2x88x92j1)xe2x80x83xe2x80x83(15) This coincides with the condition described in Japanese Patent Laid-Open No. 9-75332. If Fg slightly deviates from this condition due to a manufacturing error in the grid or the like, a stripe pattern with a very low frequency is produced. This greatly damages image information and makes it difficult to remove a grid stripe pattern by filtering or the like. By solving equation (14-2) for Fg, the following equation is obtained: F g = 2 3 ⁢ ( j 1 + j 2 ) ⁢ F n = 1 3 ⁢ ( j 1 + j 2 ) ⁢ F s ( 16 ) In this case, Fs=2xc2x7Fn (sampling frequency). In this case, (j1+j2) is a positive integer (natural number) and can take numerical values such as (2/3)Fn, (4/3)Fn, and (6/3)Fn. If, however, (j1+j2) is a multiple of three, the resultant condition is the same as that represented by equation (15). Since this condition is not appropriate as described above, this case is excluded. If the grid frequency Fg is set to satisfy equation (16) when (j1+j2) is a natural number excluding a multiple of three, there is no possibility that a low-frequency stripe pattern like that described above will be produced, even with a slight manufacturing error. In addition, if the grid frequency is set in accordance with this condition, the fundamental frequency of the grid stripe pattern and the frequency of the second-order harmonic become almost equal to each other in the image (become a substantially single spectrum), and only a substantially single stripe pattern with a sine wave is advantageously generated in the image. The present inventor has found that when the second-order harmonic component of a grid stripe pattern in an acquired image cannot be neglected, a very good effect can be obtained by setting the grid frequency so as to satisfy equation (16). In the case of general medical images, the sampling pitch is about 100 xcexcm to 200 xcexcm, and hence the Nyquist frequency Fn falls within the range of about 2.5 cyc/mm to 5 cyc/mm. The frequency Fg of a physically appropriate grid as a grid aimed at removing scattered X-rays falls within the range of about 3 cyc/mm to 10 cyc/mm. For this reason, (j1+j2)=2 exhibits a promising condition that may coincide with the condition represented by equation (16). The condition represented by (j1+j2)=3 coincides with the condition represented by equation (15), and hence is inappropriate. Therefore the condition represented by equation (17) is appropriate. F g = 4 3 ⁢ F n = 2 3 ⁢ F s ( 17 ) In this embodiment, by making the grid frequency almost coincide with a frequency that satisfies the condition represented by equation (16), the spectra of an essentially unnecessary grid stripe pattern in a sampled image can be intefrated to near Fs/3 (=2Fn/3). This makes it easy to remove a grid stripe pattern from an image by filtering or the like. According to the foregoing embodiments (Japanese Patent Application No. 2000-028161 filed by the present applicant), the grid frequency Fg is set such that the frequency of an image component originating from a grid in acquired image data becomes equal to a frequency selected from the range from 50% the Nyquist frequency Fn to 80% thereof. This condition makes moire fringes (beat-like variation components) originating from a grid less noticeable even if imaging is done with the fixed grid, and includes the condition Fg=(2/3)jFn (j is a natural number excluding a multiple of three) according to this embodiments. The solution (condition) in this embodiment which is indicated by equation (16) is a special solution obtained by also taking harmonic components (second-order harmonic component) of a grid stripe pattern into consideration, and is also made with respect to the technical problem newly found by the present inventor. This solution has the unique effect described above. Therefore, the invention described in this embodiment constitutes valid selection inventions and numerically limited inventions. FIG. 11 is a block diagram schematically showing an X-ray image acquisition apparatus according to the fifth embodiment of the present invention. A case wherein the present invention is applied to an X-ray image acquisition apparatus for imaging an object to be imaged by using X-rays will be described below. However, the present invention can also applied to an image acquisition apparatus using radiation other than X-rays. Referring to FIG. 11, reference numeral 101 denotes an X-ray generating unit which has an X-ray tube, high voltage generator, and controller and emits X-rays in the direction indicated by the arrow; 102, an object to be imaged, typically the human body; 103, a support base such as a bed which supports a lying object such as the human body; and 104, a scattered ray removing grid having lead foil members whose intervals are optimally set. This setting will be described later. Reference 105 denotes an X-ray image sensor which converts the intensity distribution of X-rays (X-ray image) transmitted through the object into an electric signal and is formed by using a large-size solid-stage image sensing element having a detection area (image-receiving area) constituted by a plurality of pixels arranged two-dimensionally in the form of a matrix. The X-ray image sensor 105 spatially samples an X-ray image through the detection area. In this embodiment, as this X-ray image sensor, a sensor exhibiting little decrease in resolving power in an energy conversion process (e.g., a sensor based on the direct conversion scheme) is used. In addition, the sampling pitch (pixel pitch) of this X-ray image sensor is set to 0.16 mm. The X-ray image sensor will be referred to as a flat panel sensor or simply as a sensor hereinafter. The flat panel sensor is controlled by a controller (not shown) to sequentially scan charges proportional to the amounts of X-rays present for the respective pixels and convert them into predetermined electrical quantities (e.g., voltages or currents), thereby outputting X-ray image information as electrical quantities. Reference numeral 106 denotes an A/D converter for converting the analog electrical quantities output from the flat panel sensor 105 into digital values; 107, a memory (storage unit) for temporarily storing a digital value from an A/D converter as image information; 108, a switch for reading out the information stored in the memory 107 and switching destinations for the information; 109, a memory (storage unit) for storing the image signal output from the X-ray image sensor 105 without irradiation of X-rays as an offset fixed pattern image; and 110, a memory (storage unit) for storing an image of the object which is obtained by actually irradiating the object with X-rays. According to a specific imaging method, an X-ray dose measuring device (not shown) called a phototimer which monitors the amount of X-rays transmitted through an object to be imaged is used to control X-ray emission by the X-ray generating unit, and X-ray emission by the X-ray generating unit is stopped at the instant when the cumulative amount of X-rays transmitted through the object becomes a predetermined value. At the same time when X-ray emission is stopped, the controller for this X-ray image acquisition apparatus causes the flat panel sensor to start scanning, and temporarily stores image information of the object 102 in the memory 107. Thereafter, the controller sets the switch 108 to the A side to make the memory 110 store the image information. Immediately after this operation, the controller causes the flat panel sensor to store charges without emitting X-rays for the same time as the X-ray emission time determined by the above phototimer, and then makes the flat panel sensor scan. The controller then causes the memory 107 to temporarily store the resultant image information as an offset fixed pattern image. After this operation, the controller sets the switch 108 to the B side to make the memory 109 store the offset fixed pattern image from the memory 107. Reference numeral 111 denotes a subtracter which sequentially subtracts, essentially from the values of object image data in the memory 110, the values of the offset fixed pattern image data in the memory 109 at the corresponding positions; and 112, a memory (storage unit) which stores the difference (image data after offset fixed pattern correction) from the subtracter 111. Reference numeral 113 denotes an LUT (Look Up Table) for converting image data into a logarithmic value; 114, a switch for switching destinations for data from the LUT 113; and 115, a memory (storage unit) for storing data from the switch 114 whose output destination is set to the C side. In general, image data from the memory 112 which is obtained through an object to be imaged is logarithmically converted by the LUT 113. The image data is then stored in the memory 115 through the switch 114 set to the C side. Reference numeral 116 denotes a memory (storage unit) for storing image data when this X-ray image acquisition apparatus performs operation called calibration imaging. In this calibration imaging, imaging is performed in the same manner as described above, and the switch 114 is set to the D side. The resultant image data is then stored in the memory 116. This operation differs from the above object imaging operation in that imaging is performed by emitting X-rays without the mediacy of the object 102. With this operation, image data (simply referred to as gain variations or gain variation data) is stored in the memory 116, which constitutes gain variations (also called sensitivity variations) of a plurality of pixels constituting the flat panel sensor and the intensity distribution (shading) of X-rays emitted from the X-ray generating unit. In general, this calibration imaging is done about once every day at the start of work. Reference numeral 117 denotes a gain corrector (subtracter) having the function of correcting image data on the basis of gain variations by subtracting the gain variation data stored in the memory 116 from the image data stored in the memory 115 for each corresponding pixel (this operation substantially equivalent to division because each data having undergone logarithmic conversion); and 118, a memory (storage unit) which stores object image data having undergone correction based on gain variations which is performed by the gain corrector 117. Grid frequency (lead foil member pitch) selection will be described below. FIG. 12 schematically shows the flat panel sensor 105 according to this embodiment. Each portion 300 indicated by a rectangle represents a portion for receiving X-ray energy (charge) upon conversion, i.e., a pixel. As described above, the pixel pitch of this sensor is set to 0.16 mm. It is, however, difficult for reasons of manufacturing techniques to match the size of one side of a pixel, i.e., aperture, with the pixel pitch, and hence the size is set to 0.14 mmxe2x96xa1. As described above, since the flat panel sensor 105 is an X-ray image sensor of the type that exhibits little decrease in rresolving power in an energy conversion process, the MTF (Modulation Transfer Function) of the sensor is mostly determined by the shape of this aperture. Referring to FIG. 13, reference numeral 301 denotes the MTF of the the flat panel sensor 105. In this graph, the ordinate represents the MTF; and the abscissa, the spatial frequency. This MTF corresponds to the data obtained by Fourier transformation of an aperture of 0.14 mm. Reference numeral 305 denotes the sampling frequency of the flat panel sensor 105, which is 1/0.16=6.25 cyc/mm; and 306, a Nyquist frequency which is 6.25/2=3.125 cyc/mm. In this case, the pitch of the shades of the lead foil members of the grid on the flat panel sensor is set to 0.24 mm. As a consequence, the fundamental spatial frequency of the grid stripe pattern becomes 1/0.24=4.17 cyc/mm. Referring to FIG. 13, this frequency is denoted by reference numeral 303. The grid stripe pattern is the shade pattern of the lead foil members. Strictly speaking, therefore, the shade pattern cannot be a sine wave but has a plurality of harmonics, and the frequency spectra of the shade pattern are a set of a plurality of line spectrum. Reference numeral 304 denotes the second-order harmonic of the grid stripe pattern, which has a frequency of (1/0.24)*2=8.33 cyc/mm. As also described with reference to equation (17), if the grid strip pattern is visualized below the Nyquist frequency by sampling, the grid stripe patterns 303 and 304 are integrated into a single spectrum (line spectrum) with a frequency of 2.08 cyc/mm. In this case and general cases, since third- or higher-order harmonics are hardly resolved even by this MTF defined by only the aperture, this spectrum is the only spectrum (line spectrum) of the grid stripe pattern which appears in an image. Referring back to FIG. 11, reference numeral 119 denotes an image processing unit which performs one-dimensional spatial filtering in a direction perpendicular to the grid stripe pattern. The image processing unit 119 selectively removes the grid stripe pattern 302 in FIG. 13. More specifically, this removal can be realized as follows. A grid stripe pattern is estimated and formed such that image components including the grid stripe pattern extracted from image dada by filtering are processed on the basis of the essential characteristics of the grid which exhibit stable periodicity. The formed grid stripe pattern is then subtracted from the original image data (this operation is substantially division because the data have undergone logarithmic conversion) (this method is disclosed in Japanese Patent Application No. 2001-134208 filed by the present applicant). Reference numeral 120 denotes a memory (storage unit) which stores image data having undergone processing by the image processing unit 119. Note that integration of the fundamental wave and second-order harmonic wave of the grid stripe pattern into substantially one spatial frequency as in this embodiment is suited to easily or properly removing the grid stripe pattern regardless of the grid stripe pattern removing method to be used. FIG. 14 shows the positional relationship between an X-ray source (X-ray focal point), a grid, and a flat panel sensor. Reference numeral 401 denotes an X-ray source; 402, a grid; and 403, a flat panel sensor. Depending on the target region of an object to be imaged, the amount of scattered X-rays is small, and imaging is performed without using the grid. For this reason, an X-ray image acquisition apparatus is generally designed to selectively use a grid. For example, a detachable grid is mechanically mounted in front of the sensor. Consequently, a small gap D is spaced between the grid and the flat panel sensor, as shown in FIG. 14. In general, an X-ray source is a nearly point ray source and placed at a distance L from the grid. The plurality of lead foil members of the grid are not simply arranged parallel to each other but are arranged at angles that make them converge to the X-ray source at this distance. In this case, since L and D are about 180 cm and 10 mm, respectively, a difference owing to a magnifying effect appears between the actual pitch of the lead foil members of the grid and the pitch of the shades of the lead foil members on the flat panel sensor. Letting g1 be the actual grid pitch, and g2 be the shade grid pitch on the sensor, the pitch g2 can be calculated by g2=g1xc2x7(1+D/L)xe2x80x83xe2x80x83(18) If the grid frequency (1/g2) on the sensor is set to 4.17 cyc/mm as in the above case, the actual grid frequency (1/g1) is preferably set to 4.17xc2x7(1+D/L)≈4.2 cyc/mm. A grid stripe pattern can be removed from the image data sampled by the flat panel sensor by one filtering operation, even if the spatial frequencies of the fundamental wave and second-order harmonic of the grid stripe pattern do not perfectly coincide with each other, as long as their difference falls within the range of errors of several %. Therefore, slight errors between them are allowed. This error ratio r is given by the following equation with reference to a target spatial frequency Fs/3: r = "LeftBracketingBar" 2 ⁢ Fs - 3 ⁢ Fg "RightBracketingBar" 1 3 ⁢ Fs ( 19 ) In general, this error ratio preferably falls within 5%. Equation (19) is generally expressed as r = "LeftDoubleBracketingBar" J 1 ⁢ Fs - Fg "RightBracketingBar" - "LeftBracketingBar" J 2 ⁢ Fs - 2 ⁢ Fg "RightDoubleBracketingBar" 1 3 ⁢ Fs ( 20 ) (Note that j1 and j2 are so selected as to satisfy \|j1Fsxe2x88x92Fg\| less than Fs/2 and \|j2Fsxe2x88x922Fg\| less than Fs/2.) Note that image processing unit 119 need not always remove a grid stripe pattern by filtering or the like unless the operator who observes the image requires so. According to this embodiment, even if a grid stripe pattern is not removed by filtering or the like, since the grid stripe pattern in the image becomes a substantially single sine wave, it does not easily interfere with observation. This embodiment has exemplified the case wherein the ideal flat panel sensor exhibiting little decrease in resolving power in an energy conversion process is used. However, the other arrangement of this embodiment can be effectively applied to a case wherein a flat panel sensor exhibiting a substantial decrease in resolving power in an energy conversion process is used. In addition, all the grid frequencies Fg set when j=(j1+j2) in equation (16) takes natural numbers other than multiples of three can be used. (Sixth Embodiment) One of the characteristic features of a flat panel sensor is that pieces of information of a plurality of pixels adjacent to each other on the sensor can be added as analog values by accumulating the charges in the plurality of pixels on the sensor. Another characteristic feature is that the driving modes of the sensor can be switched, and the sensor can be designed to switch between the addition mode of performing such analog addition and the normal mode. When, for example, the dynamic function (movement) of the heart is to be observed, the flat panel sensor is driven at a high frame rate to acquire so-called moving image data. In this case, for example, 2xc3x972 adjacent pixels are handled together as one pixel, and image information is output from the flat panel sensor. If image data with higher resolution is required as a still image, the mode of the sensor is switched to the normal mode to increase the resolution. If the data of 2xc3x972 pixels are added, the substantially sampling pitch is doubled. As a consequence, the Nyquist frequency Fnxe2x80x2 becomes (1/2)Fn. Obviously, in the addition mode, with substitution of Fn=2Fnxe2x80x2 into equation (16), the grid frequency Fg satisfies the same condition as that in the normal mode. In the X-ray image acquisition apparatus according to this embodiment as well, if the grid frequency Fg is so set as to satisfy equation (16) in the normal mode (note that j=(j1+j2) is set to a natural number other than a multiple of three), and the sampling frequency decrease ratio (which represents the number of pixels to be added in a direction perpendicular to the grid foil members, e.g., 2 in the above case of addition of 2xc3x972 pixels) due to pixel addition in the addition mode is set to a natural number other than a multiple of three, the spatial frequencies of the fundamental wave and second-order harmonic of the grid stripe pattern substantially coincide with each other in the image data sampled by the flat panel sensor regardless of the normal mode and addition mode. This makes it possible to obtain the same effect as that in the fifth embodiment. As described above, by setting the grid frequency Fg so as to satisfy equation (16) (note that j=(j1+j2) is set to a natural number other than a multiple of three), the frequencies of a grid stripe pattern in a visualized image can be converted (integrated) into a substantially single spectrum. This makes it possible to easily remove the grid stripe pattern from the visualized image. Note that the fifth and sixth embodiments are only examples in practicing the present invention. It should be noted that the technical range of the present invention is not limited by these embodiments. The present invention can be practiced in various forms without departing from the technical idea and main characteristic features of the present invention. As has been described above, according to the fifth and sixth embodiments, there are provided a radiation imaging method and apparatus which facilitate removing or reducing components originating from a grid in an acquired image or can acquire an image that is easy to observe even in the presence of such components, and a design method for the apparatus. In addition, according to the fifth and sixth embodiments, there are provided a radiation imaging method and apparatus which facilitate removing or reducing harmonic components originating from a grid in an acquired image or can acquire an image that is easy to observe even in the presence of such components, and a design method for the apparatus. According to the fifth and sixth embodiments, there are provided a radiation imaging method and apparatus which can integrate a fundamental frequency component and second-order harmonic component originating from a grid in an acquired image into a substantially single spectrum, and a design method for the apparatus. Furthermore, according to the fifth and sixth embodiments, there are provided a radiation imaging method and apparatus which can integrate components originating from a grid in an acquired image into a substantially single spectrum, and a design method for the apparatus. The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention the following claims are made.
046630856	abstract	The invention resides in an apparatus for the decontamination of radioactivated metallic waste by the electrolytic oxidation-reduction with an aqueous nitric acid solution containing trivalent cerium ions, i.e. the step of converting the trivalent cerium ions into tetravalent cerium ions through electrolytic oxidation and the step of dissolving the surface layer of the radioactivated metallic waste by oxidizing it with the electrolytic solution now vested with the oxidative power of the freshly produced tetravalent cerium ions and, at the same time, effecting regeneration of the tetravalent cerium ions. The main objects of this invention are to provide a high decontamination efficiency and suppression of the amount of secondary waste to be generated to the minimum by the apparatus which is capable of thoroughly dissolving the surface layer of the object under treatment without reference to size and shapes, the very factors that prevent the conventional methods of decontamination from fulfilling their functions indiscriminately, thereby lowering the level of radioactivity to a point where the object will be handled as safely as ordinary industrial waste.
	abstract	In order to increase the ruggedness and the scattered radiation attenuation quality, a grid (3) with comb elements (12) which absorb electromagnetic radiation and are intended to form a grid is constructed, in such a manner that comb lamellae (11) extend transversely of an associated comb base surface which supports the comb lamellae (11).
046577246	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Attention is first directed to FIG. 1 of the drawings where a logging tool 10 is suspended on a logging cable 12 in a borehole 14 to measure the response of the adjacent formation to pulsed neutron flux. In the sonde supporting the present apparatus, the numeral 16 identifies a pwoer supply in accordance with the teachings of this invention. It is connected to a neutron generator tube 20. The neutron generator 20 forms pulsed neutron flux which is directed to the adjacent formation. The neutron flux typically is fourteen Mev neutrons in timed sequence. The neutrons bombard the adjacent formation, and some type of response is noted in a detector 18 in the sonde 10. The detector 18 is connected through the logging cable 12 to provide output signals to the surface. The logging cable 12 is spooled over a sheave 22 and the cable is stored on a drum or reel 24. The cable might be as long as 25,000 feet to obtain measurements from a well of that depth. The cable includes suitable conductors which are output from the cable to a data processor 26. The data processor converts the data into a suitable form which is then input to a recorder 28. The data recorder 28 records the data from the detector 18. Preferably, the data is recorded as a function of sonde depth in the well, and to this end, an electrical or mechanical depth measuring apparatus 30 is connected from the sheave 22 to the recorder 28 whereby the data is recorded as a function of depth. Ordinarily, the sonde 10 is lowered to the bottom of the well and then retrieved, recording data as it is pulled up the borehole, and the data is recorded opposite depth on a suitable recording media for later interpretation and analysis. Attention is directed to FIG. 2 of the drawings which shows the power supply 16 connected to the neutron generator 20. First of all, a brief description should be noted regarding the generator 20. It is connected with a high voltage power supply, typically a 100 Kv power supply 32. The suitable high voltage is connected to the target of the neutron generator 20. It is also provided with a replenisher power supply 34. The pulsed neutron generator is sequenced off and on to form neutron bursts in a timed sequence by means of the pulsed power supply circuit 16 shown in FIG. 2. Operation of this power supply can be understood best by proceeding with a description of the components thereof. A transformer 36 is connected to a suitable alternating current supply. The transformer secondary is connected to a rectifier bridge 38 providing full wave rectification. There is an output filter capacitor 40 to smooth ripple and a Zener diode 42 is connected across the filter capacitor. The diode 42 provides a voltage for a transistor 44 which is further operated to smooth ripple in the output voltage. The power supply described herein preferably provides an output of about minus twelve volts referenced to a conductor 46. The conductor 46 proceeds to other circuit components as will be described. It should be noted that this circuit provides an operating voltage for the circuit components, particularly those associated with forming the control pulses. This supply is floating on a high voltage line. That is, it is isolated from ground. The numeral 48 identifies a high voltage supply. In the preferred embodiment, this is typically in the range of about 2,000 volts. The high voltage supply 48 is input to the circuit at several locations. At the several connections, the high voltage is normally furnished substantially free of noise and ripple. FIG. 2 further shows a string of FET transistors. They are divided into two groups. The FET transistors are connected between the high voltage supply 48 and ground. The output conductor 50 is between the two groups of FETs. Considering the two groups, the FET connected to ground is the transistor 51. In addition to that, there is another transistor 52 serially connected. A third transistor 53 completes the lower group. In similar fashion, the upper group includes the transistors 54 through 58 connected serially as illustrated. Assuming that about 2,000 volts are applied at the high voltage supply 48, it will be recognized that the full voltage of the supply is across either one group or the other but not both. To this end, the transistors 51, 52 and 53 are preferably rated at about 1,000 volts each. The other group of transistors can utilize transistors having a rating of about 500 volts. It will be further noted that the transistors 51-53 are connected so that the source of the transistors 51 is connected to ground and the drain is connected to the source of the transistor 52. Because of the polarity (compared with the deployment of the transistors in the second group), the transistors 54-58 are inverted compared to transistors 51-53. That is, the transistor 51 is connected to ground through the source. Contrary to this, the transistor 58 is connected to the high voltage supply 48 through its source. It will be further noted only the transistors 51 and 58 receive control signal inputs. That is, pulses are applied to these transistors only and switching of this pair control switching of all the circuitry. To this end, the transistors 52-57 operate on a ripple effect. More will be noted concerning this later. This is accomplished by providing the transistor 52 with a gate input voltage which is determined by a diode and resistor network connected to it. The illustrated network of various Zener diodes connected to the gases of transistors 52-57 is provided to enable and insure that the gate voltages are spaced so that the full drop from the supply (2,000 volts in this embodiment) is not across a single transistor. By spreading the intermediate points between ground and 2,000 volts, it is possible to use derated FETs. In this embodiment, the transistors 51-53 can be rated at 1,000 volts. To this end, the string of Zener diodes controlling the intermediate points include diodes 62 and 63 for the lower set of transistors, and diodes 64-67 in the upper section of FETs. In the upper section, the 2,000 volt differential can be spread across the five FETs and therefore requires only that they operate at about 500 volts each. As will be further observed, the respective gates of transistors 52-57 are clamped by diode and Zener diode networks connected from the source to the setpoint Zeners. A timing circuit 70 forms four pulses for operation of the pulsed power supply 16. The timing circuit 70 forms four outputs on four conductors. One is on a conductor 71. A second conductor 72 is also output. FIG. 3 shows timing of a pulse on the conductor 71 which occurs one or two microseconds in advance of the pulse on the conductor 72. It is important that they occur in this sequence, namely, an on pulse applied on the conductor 71 before an on pulse is placed on the conductor 72. There is an additional conductor 73 which connects with other circuitry in conjunction with the conductor 72 (all will be described hereinafter) and both have superimposed pulses on them. The pulse on conductor 73 best occurs one or two microseconds in advance of a pulse on the conductor 74. The relative position of the four pulses in FIG. 3 shows the relative sequence. The timing circuit 70 controls a burst of neutrons during the interval determined by these four pulses. That neutron burst occurs beginning with receipt of the pulse on the conductor 72 which defines the leading edge of the neutron burst and extends until the pulse on the conductor 73 has occurred. More will be noted regarding the disposition of these pulses hereinafter. It will be observed that the conductors 72 and 73 are input to the set and reset terminals of a flip-flop. The flip-flop 75 forms an output on the Q terminal which is input by conductor 76 to the gate of the FET 58. In similar fashion, a flip-flop 77 is providd with the conductors 71 and 74 input to the set and reset terminals respectively. Again, the output is formed on the Q terminal and provided on a conductor 78 to the gate of the FET 51. Consider now the sequence of operation shown in FIG. 3. Keep in view that the timing circuit 70 forms pulses applied to the conductors in sequence, that is, a pulse is first placed on the conductor 71 and thereafter on the conductor 72. Pulses are applied to conductors 73 and 74 in that sequence all as shown in FIG. 3. A pulse on the conductor 71 achieves the following results. Assume initially that the bottom section of three FETs is on (or conductive) while the top section is off or non-conductive. In the event, the voltage on the conductor 50 is not high voltage and is approximately ground voltage. Proper operation of the neutron generator 20 requires a positive pulse of about 2,000 volts. That pulse is formed on the conductor 50 for the neutron generator 20. Accordingly, the initial condition finds the bottom section on, bringing the conductor near to ground. No current flows through the top FETs because they are switched off or block the application of high voltage to the conductor 50. When a pulse is applied on the conductor 71, to the flip-flop 77, this forms a negative going pulse on the conductor 78 and cuts off the transistor 51. When it is cut off, current flow through the transistors 52 and 53 is also cut off, and the diode biased circuitry for the transistors 52 and 53 cuts each one off in sequence in a ripple. This then permits the conductor 50 to be isolated from ground so that it can either be at ground or at high voltage depending on the upper set of FETs. The next pulse of interest is formed on the conductor 72 and is applied to the set terminal of the flip-flop 75. This causes the flip-flop 75 to form a negative going pulse on the conductor 76. A negative going pulse is thus applied to the gate of the transistor 58. Recall that the transistor 58 is inverted in contrast with the transistor 51. Accordingly, the negative going pulse switches the transistor 58 on or makes its conductive. When it conducts, it causes conduction through the transistor 57 and in cascade effect transistors 56, 55 and 54. The several transistors are rippled in relatively high speed. This makes all the transistors conductive between the conductor 50 and the high voltage supply 48. It brings the conductor 50 to about 2,000 volts and thereby applies the high voltage to the neutron generator tube 20. It is desirable to accomplish switching in this sequence. It is undesirable that all eight transistors be conductive at the same instance because that would substantially ground the high voltage supply and would burn up the transistors. Therefore, the lower set of transistors is switched off one or two microseconds in advance of switching the other transistors on to achieve conduction. At this juncture, this condition prevails for an indefinite period, and high voltage through the conductor 50 is supplied to the neutron generator. The interval is determined by the timing circuit 70. The timing circuit subsequently operates to switch off the pulse of high voltage applied to the neutron generator 20. Switch off is achieved by providing a pulse on the conductor 73 and a follow-up pulse on the conductor 74, the two pulses being separated typically about one or two microseconds. First of all, the pulse on the conductor 73 reverses the operative state of the flip-flop 75 and forms a positive going output pulse on the conductor 76. That is applied to the gate of the transistor 58 and switches that transistor off, rendering it non-conductive. When it switches off, a ripple effect is observed through the serially connected FETs. This drops the voltage at the conductor 50 from the high voltage of the supply 48 toward ground potential. After this has occurred, the pulse on the conductor 74. reverses the operative state of the flip-flop 77 and forms a control pulse for the FET 51. That transistors is then operated to switch from off to on, thereby rippling through the transistors 52 and 53. This brings the conductor 50 close to ground potential and completes grounding of the conductor 50. At this point in time, the neutron burst from the neutron generator 20 has been terminated. The control circuit 70 is thus operated to vary the time span between the pulses 72 and 73. This time span determines the duration of the neutron burst. Because it can be widely tuned, substantially any practical pulse width can be obtained and pulse spacing or frequency of pulses can likewise be modified. Ideally, there is a lag time of about one or two microseconds at the start of each pulse and at the end of each pulse to insure interlocking of the pulses on the conductors 71-74, inclusive. Further, the pulses on the four conductors need not be long pulses but can be relatively short, as short as practical depending on the speed of the flip-flops 75 and 77. From the foregoing, it will be observed how pulse width and frequency of the neturon generator can be controlled through the power supply 16 of this disclosure. This apparatus is operative at temperatures typically encountered in deep wells. Thermal runaway has little impact on the operation of the circuit so that it can be operated in the manner described both at ambient temperatures and the elevated temperatures observed in deep wells. While the foregoing is directed to the preferred embodiment, the scope of the disclosure is determined by the claims which follow.
	description	This application is a continuation-in-part of U.S. patent application Ser. No. 10/089,530 filed on Aug. 19, 2002 now abandoned which is based on PCT Application No. PCT/FR00/02666 filed on Sep. 27, 2000 which is based on French Patent Application No. 99 12247 filed on Sep. 30, 1999. The present invention relates to zirconium-based alloys that are to constitute nuclear fuel assembly components usable in light-water nuclear reactors, such as nuclear fuel rod claddings or assembly guide tubes, or even flat products, such as grid plates. The invention may be used, although not exclusively, in the field of the manufacture of cladding tubes for fuel rods intended for pressurized-water reactors in which the risks of corrosion are particularly high as a result of a high lithium content and possibly as a result of risk of boiling, and also in the field of strip materials used for structural components of the fuel assemblies of such reactors. The invention also proposes a method for making such components. Patent application PCT FR99/00737 proposes a zirconium-based alloy also containing, by weight, apart from unavoidable impurities, from 0.03 to 0.25% in total of iron, on the one hand, and of at least one of the elements of the group constituted by chromium and vanadium, on the other hand, having from 0.8 to 1.3% of niobium, less than 2000 ppm of tin, from 500 to 2000 ppm of oxygen, less than 100 ppm of carbon, from 5 to 35 ppm of sulphur and less than 50 ppm of silicon, the ratio of the iron content, on the one hand, to the chromium or vanadium content, on the other hand, being from 0.5 to 30. The invention is based on observations made by the inventors in the course of a systematic study of the intermetallic phases and the crystallographic forms of those phases which appear when the relative contents of iron and niobium are varied while the contents of tin, sulphur and oxygen are described in the application mentioned above. It is also based on the observation, made experimentally, that the nature and the crystallographic form of the intermetallic phases containing zirconium, iron and niobium have a major influence on corrosion resistance in various environments. In particular, it has been found that the presence of compounds having a crystalline structure with a face-centered cubic lattice, obtained owing to a proportion of iron relative to niobium sufficient to result in the presence of (Zr Nb)4Fe2, at the expense of the compound Zr (Nb, Fe)2 having a hexagonal lattice, and of the phase βNb, which predominate at the high Nb/Fe ratios, substantially improves corrosion in a medium having a high lithium content, such as that which exists at the beginning of an operating cycle of some pressurized-water reactors. On the other hand, the presence of the phase having a face-centered cubic lattice in too large a quantity slightly impairs corrosion resistance in an aqueous medium. The present invention aims especially to provide an alloy which enables components to be obtained wherein the composition may be adapted in an optimum manner to the conditions of use provided for and whose composition is not likely to hamper the manufacturing steps excessively. To that end, the invention proposes, in particular, a zirconium-based alloy also containing, by weight, apart from unavoidable impurities, from 0.02 to 1% of iron, preferably 0.05 to 1%, more preferably 0.3% to 0.35%, from 0.8% to 2.3% of niobium, less than 2000 ppm of tin, less than 2000 ppm of oxygen, less than 80 ppm of carbon, from 5 to 35 ppm of sulphur and less than 0.25% in total of chromium and/or vanadium, the ratio R of the niobium content less 0.5% to the iron content, optionally supplemented by the chromium and/or vanadium content, being lower than 3. The choice of the ratio R=(Nb-0.5%)/Fe+Cr+V results from the observation that the phase having a face-centered cubic lattice appears as soon as the relation between the content of Fe (and also of Cr and V if they are present) and the content of Nb is such that R is lower than a threshold which depends slightly on the contents of other elements and on the temperature but is at most 3. The invention also proposes a method for making a tube according to which: a bar is produced from a zirconium-based alloy also containing, by weight, apart from unavoidable impurities, from 0.02 to 1% of iron, from 0.8% to 2.3% of niobium, less than 2000 ppm of tin, less than 2000 ppm of oxygen, less than 100 ppm of carbon, from 5 to 35 ppm of sulphur and less than 0.25% in total of chromium and/or vanadium, the ratio of the niobium content less 0.5% to the iron content, optionally supplemented by the chromium and/or vanadium content, being lower than 3; the bar is water-quenched after heating at from 1000° C. to 1200° C.; a blank is extruded after heating at a temperature of from 600° C. to 800° C.; the blank is cold-rolled in at least two passes to obtain a tube, with intermediate thermal treatments at from 560° C. to 620° C.; and a final thermal treatment is carried out at from 560° C. to 620° C., preferably 560° to 600° C., more preferably 560° C. to 580° C., all of the thermal treatments being carried out in an inert atmosphere or under vacuum. The final thermal treatment leaves the tube in the recrystallized state, which promotes creep strength, without modifying the nature of the phases. The addition of chromium and/or vanadium, which is substituted for iron and niobium in the hexagonal phase, enables the proportion of the two phases, hexagonal and face-centered cubic, to be controlled. The alloy may also be used to produce flat elements. Those elements are also used in the recrystallized state and may be manufactured by the following sequence: a blank is produced from a zirconium-based alloy also containing, by weight, in addition to unavoidable impurities, from 0.02 to 1% of iron, preferably 0.05 to 1%, more preferably 0.3% to 0.35%, from 0.8% to 2.3% of niobium, less than 2000 ppm of tin, less than 2000 ppm of oxygen, less than 80 ppm of carbon, from 5 to 35 ppm of sulphur and less than 0.25% in total of chromium and/or vanadium, the ratio R of the niobium content less 0.5% to the iron content, optionally supplemented by the chromium and/or vanadium content, being lower than 3, the blank is cold-rolled in at least three passes, with intermediate thermal treatments and a final thermal treatment, one of those intermediate thermal treatments or a preliminary thermal treatment before the first cold-rolling pass being effected for a long period of at least 2 hours at a temperature lower than 600° C., and any thermal treatment following the long treatment and, in particular, the final recrystallization treatment, being effected at a temperature lower than 620° C. Preferably, the final recrystallization treatment is effected between 560° C. and 600° C., more preferably between 560° C. and 580° C. The invention also proposes the application of the above alloy to the production of components of nuclear reactors operating with pressurized water that initially contains less than 5 ppm of lithium. Although that content then decreases rapidly, owing to its consumption in order to adjust the pH of the coolant, it may be important to avoid rapid initial corrosion. The existence of the intermetallic compounds, which is due to the presence of iron in a sufficient quantity, including the existence of Zr (Nb, Fe)2, reduces the amount of niobium precipitates in phase β which do not promote corrosion in a lithium-containing medium, but also the niobium content of the solid solution and therefore gives satisfactory resistance to uniform corrosion at a temperature of approximately 400° C., which is representative of the temperature that prevails in reactors. An iron contenct of 0.02 to 1% is considered to be in accordance with the invention. But for iron contents of 0.05% and more within this range, a signicant increase of the reistance to corrosion in a lithium-containing medium at approximately 400° C. can be noticed. The value 0.05% corresponds to a volume fraction for βNb identical to the volume fraction for Zn(Nb,Fe)2. The presence of chromium and/or vanadium as a very partial replacement for iron in the intermetallic precipitates of the type Zr (Nb, Fe, Cr, V)2 has no marked effect on corrosion at 400° C. because chromium and/or vanadium is simply substituted for iron and/or niobium in the intermetallic compound as the chromium content increases. The improved corrosion resistance at 400° C. is maintained especially if the sum Fe+Cr (optionally plus vanadium) is at least 0.03%. The carbon content of the alloy must be kept at less than 80 ppm. It has been noticed that corrosion in a lithium-containing medium at approximately 400° C. dramatically increases after 50 days of exposure if the carbon content is over 100 ppm. A lessening of the carbon content to 100-80 ppm allows attenuation of this increase, but keeping the carbon content under 80 ppm allows this increase to happen only after 100 days or more. To summarize, an alloy of the above type having a use in the recrystallised state to increase its resistance to the bi-axial creep of tubes and the aptitude for the pressing of sheet metal has characteristics which are adjustable by regulating the iron/niobium ratio but which are still favourable to: a high corrosion resistance in an aqueous medium at high temperature, which medium optionally contains lithium, the resistance being all the higher in this last-mentioned case if a high iron content is adopted, which is permitted by a high Nb content and with an iron/niobium ratio exceeding 0.3, a high creep strength owing to the presence of tin which remains at a very low content and, owing to doping with oxygen, at a content lower than 2000 ppm, which then has no harmful effect on corrosion resistance. In current reactors, the ranges given below are particularly valuable as a zirconium-based alloy also containing, by weight, apart from unavoidable impurities: Nb: 0.8% to 1.1% by weightFe: 0.3% to 0.35% by weightSn: 0.15% to 0.20% by weightCr and/or V: 0.01 to 0.1% by weightO2: 1000 to 1600 ppmS: 5 to 35 ppmC: less than 80 ppm Referring to the FIGS. 1 to 3, the carbon and oxygen contents of obtained samples are substantially identical for all of the samples and were lower than the maximum values given above. The tin content was 0.2% and the sulphur content was 10 ppm. The samples were manufactured by thermo-metallurgical operations at a temperature not exceeding 620° C., any treatment exceeding that value beyond the extrusion operation reducing corrosion resistance at high temperature. The ternary diagram in FIG. 1 shows, for Fe/Nb ratios lower than approximately 0.3, the existence of a region in which the αZr phase (with the exclusion of the βZr phase which is very detrimental from the point of view of corrosion resistance), the βNb phase precipitates and the intermetallic phase Zr (Nb, Fe)2, which has a hexagonal structure, co-exist. For a high Fe/Nb ratio, up to a niobium content of the order of 50%, which is higher by more than one order of magnitude than the contents used, the compound (Zr, Nb)4Fe2, which is face-centered cubic, also appears. The βNb phase disappears completely only at a Fe/Nb ratio of the order of 0.6. As will be seen hereinafter, it appeared that a high niobium content is very favorable to corrosion resistance in lithium-containing water. The coexistence of the cubic and hexagonal phases is promoted by a Fe/Nb ratio higher than 0.3, while respecting the relation (Nb-0.5%)/Fe+Cr+V>2.5. A precise study of the ternary diagram for the low Fe and Nb contents shows that the Nb content in solid solution develops with the Fe content, with Nb remaining constant. As soon as the Fe content exceeds 60-70 ppm for the alloy according to the present invention, the hexagonal Zr (Nb,Fe)2 form appears which substitutes the βNb phase for a ratio by weight of Nb/Fe substantially equal to 2.3. There then appears the face-centered cubic compound (Zr, Nb)4Fe2, corresponding to Nb/Fe substantially equal to 0.6. This face-centered cubic phase (Zr, Nb)4Fe2 starts to appear for: 1% Nb from 0.29 to 0.44% Fe 1.5% Nb from 0.49 to 0.66% Fe 2% Nb beyond 0.78% Fe The diagram shows that, by simultaneously increasing the content of Nb and of Fe, a higher density of intermetallics is obtained, which promotes corrosion in a lithium-containing medium. The influence of the Fe and Nb contents is shown more clearly in FIG. 3 which gives the measurement of the weight of alloy samples after maintenance for 84 days in water containing 70 ppm of lithium at a temperature of 360° C.; the measurement of the weight of a sample of Zircaloy 4 under the same conditions was 35.96 mg/dm2. The value of the simultaneous presence of a high content of niobium and iron and of the observance of the condition explained above will be immediately appreciated. The influence of iron alone on the weight of an alloy containing Nb=1%, 0=990 ppm, C=34 ppm, S=9 ppm is shown on FIG. 4, for iron contents between 0.0139 and 0.0922%. It was also noticed that the temperature of the final recrystallization treatment has a significant influence on the corrosion behavior in a lithium-containing medium. As stated before, if the recrystallization is performed at more than 620° C., the resistance to corrosion at high temperatures is unacceptably low, But a significant downgrading of the corrosion resistance in a lithium-containing medium can be noticed already for recrystallization temperatures of 600° C. and more: an increase of the corrosion speed is observed after at most 50 days of exposure. For recrystallization temperatures of 560° C. to 580° C., such a downgrading occurs only after 100 days of exposure, or more.
	claims	1. A collimator for use in shaping a beam directed along a central axis, comprising:a first assembly, rotatable about said central axis, and having a first and a second jaw movable toward each other and toward said central axis; anda second assembly, positioned between said first assembly and a treatment zone, said second assembly being rotatable about said central axis independently from the rotation of the first assembly about said central axis, and having a third and a fourth jaw movable toward each other and toward said central axis, said third and fourth jaw each having a plurality of independently controllable elements disposed thereon that are individually operable to move toward said central axis,wherein each of said first and said second assemblies and said plurality of independently controllable elements are controllably positionable independently of each other to shape said beam. 2. The device of claim 1, wherein each of said jaws is formed of a radiation attenuating material. 3. The device of claim 1, wherein each of said jaws is formed of a material which has x-ray transmission characteristics of less than or equal to an average of one (1) percent. 4. The device of claim 1, wherein said first assembly is rotatable about said central axis from −180 degrees to +180 degrees. 5. The device of claim 1, wherein said second assembly is rotatable about said central axis from −180 degrees to +180 degrees. 6. The device of claim 1, wherein each of said plurality of elements includes a tongue and groove section for mating with another of said plurality of elements. 7. The device of claim 1, wherein said beam is an X-ray beam. 8. The device of claim 1, wherein said beam is an electron beam. 9. The device of claim 1, wherein said beam has a mixed modality of both X-rays and electrons. 10. A radiation therapy system, comprising:a beam generation device, directing a beam along an axis;a treatment head coupled to a control device, said treatment head having a first and a second radiation blocking device, said first and second radiation blocking devices independently rotatable by said control device about said axis to selectively shape said beam, said second radiation blocking device further comprising:a first jaw and a second jaw, each jaw comprising a plurality of elements disposed thereon that are individually positionable by said control device to move toward each other and toward said axis;wherein each of said first jaw, said second jaw, and said plurality of elements are independently positionable by said control device. 11. The radiation therapy system of claim 10, wherein said second radiation blocking device is positioned between said beam generation device and a treatment table. 12. A radiation therapy system, comprising:a control device, storing radiation treatment data defining a desired treatment plan;a beam generation device, controllable by said control device to deliver a beam along an axis towards a treatment zone;a first radiation blocking device, controllable by said control device to rotate about said axis; anda second radiation blocking device, positioned between said first radiation blocking device and said treatment zone, controllable by said control device to rotate about said axis independently of said first radiation blocking device, said second radiation blocking device comprising a first jaw and a second jaw, each jaw comprising a plurality of independently controllable elements disposed thereon that are individually operable to move toward each other and toward said central axis;wherein said first and said second radiation blocking devices are rotatable about said axis and at least one of said elements are independently controllable to shape said beam according to said radiation treatment data. 13. A radiation therapy method, comprising:establishing a treatment plan;rotating a first and a second radiation blocking device about an axis to produce a portal shape, said second radiation blocking device comprising a pair of jaws independently rotatable of said first radiation blocking device and having a plurality of elements disposed thereon that are individually movable toward each other and toward said axis;adjusting a position of at least one of said plurality of elements to adjust said portal shape according to said treatment plan; anddirecting a radiation beam along said axis toward a treatment zone, said radiation beam shaped by said first and second radiation blocking devices and said plurality of elements of said second radiation blocking device. 14. The radiation therapy method of claim 13, wherein said first and second radiation blocking devices are oriented to conform said portal shape to a shape of said treatment zone. 15. The radiation therapy method of claim 13, wherein said first and second radiation blocking devices are oriented to minimize the effective penumbra of said radiation beam created as said beam passes said first and second radiation blocking devices. 16. The radiation therapy method of claim 13, wherein said first and second radiation blocking devices are oriented to minimize the undulation of said radiation beam created as said beam passes said first and second radiation blocking devices. 17. The radiation therapy method of claim 13, further comprising:further adjusting at least one of said first and second radiation blocking devices after directing said beam. 18. The collimator of claim 1, at least one of said plurality of elements having a top segment, a bottom segment and a tongue-and-groove segment disposed therebetween, to minimize beam leakage and beam edge penumbra of the beam. 19. The radiation therapy system of claim 10, at least one of said plurality of elements having a top segment, a bottom segment and a tongue-and-groove segment disposed therebetween, to minimize beam leakage and beam edge penumbra of the beam. 20. The radiation therapy system of claim 12, at least one of said plurality of elements having a top segment, a bottom segment and a tongue-and-groove segment disposed therebetween, to minimize beam leakage and beam edge penumbra of the beam. 21. The radiation therapy method of claim 13, at least one of said plurality of elements having a top segment, a bottom segment and a tongue-and-groove segment disposed therebetween, to minimize beam leakage and beam edge penumbra of the beam. 22. The collimator of claim 1, wherein said elements are formed to move in an arc toward said central axis, a shape of said arc selected to maintain an end of each of said elements to match a beam edge divergence from a radiation source. 23. The radiation therapy system of claim 10, wherein said elements are formed to move in an arc toward said central axis, a shape of said arc selected to maintain an end of each of said elements to match a beam edge divergence from a radiation source. 24. The radiation therapy system of claim 12, wherein said elements are formed to move in an arc toward said central axis, a shape of said arc selected to maintain an end of each of said elements to match a beam edge divergence from said beam generation device. 25. The method of claim 13, wherein said elements are formed to move in an arc toward said central axis, a shape of said arc selected to maintain an end of each of said elements to match a beam edge divergence from a source of said radiation beam.
	summary
	summary
045487820	summary	BACKGROUND OF THE INVENTION This invention relates in general to methods and apparatus for transferring energy to a magnetically confined plasma. More particularly, this invention relates to a method and apparatus for heating a tokamak-confined plasma to thermonuclear temperatures by injecting an intense, pulsed, space-charge-neutralized ion beam into the plasma. Various techniques of heating tokamak-confined plasma have been proposed in controlled thermonuclear fusion research in an effort to provide an ionized gaseous plasma of sufficient density and temperature to sustain fusion reactions. Heretofore such reactor conditions have not been attained because insufficient heating, plasma-confinement instabilities, and energy-loss mechanisms prevent the plasma from reaching the required temperatures. It is generally agreed that ohmic heating by the main plasma current is ineffective near reactor temperatures because the plasma resistivity is a sharply decreasing function of temperature. Present-day experiments show that chemically heated tokamaks fall for short of reactor temperatures. Since ohmic heating is insufficient, supplementary heating is required and techniques such as heating with neutral beams, microwave power and intense electron beams have been proposed. It is necessary that the power produced by these supplementary techniques be deposited near the center of the reactor plasma so that the energy is confined in the plasma and does not escape out of the plasma to the walls of the tokamak, thus introducing impurities from the wall into the system. These impurities, at best, cause inefficient heating--they may even result in the cooling of the confined plasma. The injection of neutral beams into the confining magnetic field is recently regarded as the most promising method of supplementary heating. However, neutral beams can only be efficiently produced for energies less than 160 keV for deuterons (80 keV for protons). Considerably larger energies are needed if the neutral beam is to be deposited near the center of the reactor plasma. Microwave power can be delivered to the tokamak by waveguides attached to openings in the side walls, or by large coil structures inside the main vacuum chamber. This approach is limited by difficulty in controlling where in the plasma the microwave power is deposited, and also by anomalous scattering or anomalous absorption of the microwave power in the outer regions of the plasma due to parametric instabilities. The injection of intense pulsed electron beams is a possible means of heating tokamak plasmas. However, the time required for relativistic electrons to deposit their energy into a plasma is very long so that some anomalous stopping of the beam must be invoked. This is very speculative and, even if there is an anomalous stopping, there may also be associated energy loss from the plasma. For instance, experiments have shown that discharges with runaway electrons can be very destructive to tokamak liners. In ohmic heating, heating with neutral beams and heating with microwave power, the tokamak current is driven, i.e., the plasma is the secondary of a transformer whose flux runs through the center of the tokamak. This current-control system represents a very large part of the cost and complexity of a tokamak. SUMMARY OF THE INVENTION The present invention provides for heating a reactor plasma by the injection of an intense, pulsed ion beam into the plasma. The present invention has the advantage that ion beams can be produced efficiently over a wide range of voltages and currents. Ion beams are characterized by enormous power and very short delivery time. In the present invention, the ion beam is first injected nearly tangent to the field and then the plasma column is built around it. Heating of the plasma electrons and ions by classical collisions with the ion beam can be sufficient to produce ignition. In a first embodiment, a full density plasma is produced only in the center of the tokamak, the beam is shot into the target plasma, and then when the beam is trapped in the center, the remaining plasma is built up around it by gas puffing. The initial target plasma must carry the full tokamak current. However, once the ion beam is injected, it maintains the current, even long after it has lost its energy. Thus, the plasma-current-production system can be reduced in cost and complexity. In a second embodiment, a low-density plasma is produced and fills the tokamak. The beam is then shot into the plasma and generates current and poloidal field, causing it to be trapped in the center, after which the remaining plasma is built up around it by gas puffing. The ion beam provides the full tokamak current which persists long after the beam has lost its energy, so that the plasma current system can be completely eliminated. Additional advantages and features will become apparent as the subject invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
042016908	description	DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing shows a cave 1 in which is located a dissolver where irradiated nuclear fuel is dissolved in nitric acid. The cave 1 is fitted with carbon dioxide. The carbon dioxide atmosphere is continuously circulated round the plant and on leaving the cave 1 is passed to one of two dryers 2a, 2b which are connected in parallel and are used alternatively to remove water from the carbon dioxide, the water being removed from one dryer whilst the other is in use and has carbon dioxide passing through it. The carbon dioxide then passes to one of two cold traps 3a, 3b which are used alternatively and in which condensible contaminants such as iodine are separated from the carbon dioxide. The flow of carbon dioxide then passes to one of two heat exchangers 4a, 4b where the carbon dioxide is condensed as a film of solid carbon dioxide. The heat exchanger in which condensation occurs is cooled by a refrigerant which is circulated from a tank 5 round a cold fluid loop 6 by a pump 7. The cold fluid loop 6 contains valves 8, 9, 10, 11. When valves 8 and 9 are opened and valves 10 and 11 are closed the heat exchanger 4a is connected into the cold fluid loop 6 whereas when valves 10 and 11 are open and valves 8 and 9 are closed it is the heat exchanger 4b which is connected into the cold fluid loop. The temperature in the cold fluid loop 6 is conveniently around -95.degree. C. and the refrigerant may be a mixture of methylene chloride and chloroform in the ratio 90:10. Whilst carbon dioxide is being condensed in one of the heat exchangers carbon dioxide to replace that being condensed is being evaporated from the other heat exchanger by passing a liquid at a temperature above the evaporation temperature of the condensed carbon dioxide through the heat exchanger. The liquid at this temperature is circulated in a hot fluid loop 12 by a pump 13. The liquid which may conveniently be at a temperature of -65.degree. C. is pumped from a tank 14 and the flow to one or other of the heat exchangers 4a, 4b is controlled by valves 15, 16, 17, 18. When valves 15 and 16 are open and valves 17 and 18 are closed the hot fluid 12 is connected to the heat exchanger 4b whereas when the valves 17 and 18 are open and the valves 15 and 16 are closed the heat exchanger 4a is connected to the hot fluid loop 12. A suitable liquid for use in the hot fluid loop 12 is a mixture of methylene chloride and chloroform. The carbon dioxide evaporated from the heat exchanger passes back to the cave 1 through a heater 19 and a surge vessel 20. A pressure controller 21 communicating with the surge vessel 20 and linked to a valve 22 in the hot fluid loop 12 controls the rate of evaporation and a pressure controller 23 communicating with the cave 1 and linked to a valve 24 in the cold fluid loop 6 controls the rate of condensation. The heat exchangers 4a, 4b are used alternately as condensors and evaporators, the function of the heat exchanger depending on which of the fluid loops 6, 12 is connected to the heat exchanger. The inflow to the heat exchangers is controlled by valves 25, 26 and the outflow is controlled by valves 27, 28. As the carbon dioxide is condensed in one of the heat exchangers the gases such as krypton, xenon and any air which has leaked into the plant do not condense and may be removed by purging. The heat exchangers 4a, 4b are provided with outlets 29, 30 respectively to facilitate this purging. After purging the contaminant gases are recovered by known methods. The contaminant gases are at a much greater concentration in the purge gas than they are in the air stream leaving a plant in which ventilation is achieved by passing air through the plant, through decontamination facilities and then releasing the air to the atmosphere. It is therefore easier in a plant constructed in accordance with the present invention to separate the gases krypton and xenon from the atmosphere above a plant in which irradiated nuclear fuel is treated. The driving force to circulate the carbon dioxide around the plant is provided by the condensation and evaporation of the carbon dioxide in the heat exchangers 4a, 4b. Thus there is no need to have pumps or fans to circulate the carbn dioxide. In plants in which radioactive materials are handled all operations have to be performed remotely to protect the operators from exposure to radioactivity. It is therefore advantageous to have no plant components, such as pumps and fans, which require maintenance. In a plant in which nuclear fuel is treated it is necessary to filter the atmosphere of the plant to remove particulate radioactive materials. In a plant constructed according to the present invention the condensation of the carbon dioxide or other gas causes deposition of particulate materials in the heat exchangers and thus the need for filtration of the atmosphere is reduced.
	abstract	Beam detectors configuring a beam monitor are connected to a single current measurement apparatus through respective switches. If a width of a beam incident hole of each of the beam detectors 32 in the X direction is Wf, a gap between the beam incident holes of adjacent beam detectors in the X direction is Ws, a beam width of the ion beam in the X direction is Wb, a total number of beam detectors is “p”, and “n” is an integer of 0≦n≦(p−2) and satisfying Wb<{n·Wf+(n+1)Ws}, a measuring process of receiving the ion beam by the beam monitor and measuring the waveforms of the beam currents flowing into the current measurement apparatus in a state in which the plurality of switches skipped by “n” are simultaneously switched ON and a switching process of switching the switches simultaneously switched ON under the condition, are repeated.

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