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	abstract	Techniques for detecting ion beam contamination in an ion implantation system and interlocking same are disclosed. An ion beam is generated. One or more ion detectors located at trajectories off of that of the ion beam. Ion current levels detected by the one or more off-trajectory detectors are used to calculate a level of ion beam charge contamination. If contamination exceeds a predetermined level, process interlock may occur to prevent dosimetry errors.
	abstract	A device for measuring and correcting a parallelism error of an upper plug end of a nuclear fuel rod comprising mechanisms for measuring a parallelism error and for correcting said error, and a mechanism for positioning said device on the fuel rod and cooperating with a rack on which the fuel rod is stored, said correction means being arranged opposite the measuring mechanism relative to the location of the fuel rod, in order to allow a measurement of the parallelism error during correction of said error.
	summary
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050376071	claims	1. A structural component for constituting a reactor core, comprising: one and the other metallic members arranged adjacent to each other in a reactor, and reduction means for reducing a difference swelling between said metallic members due to neutron irradiation thereto, wherein said one metallic member is at least one of a metallic cladding tube and a tubular member enclosing a plurality of said cladding tubes therein and said other metallic member is a tubular member adjacent said one metallic member and enclosing a plurality of said cladding tubes therein, said reduction means for reducing a difference in swelling between said one and said other metallic members due to neutron irradiation thereto simultaneously enabling reduction of both interaction between said cladding tubes and said tubular member enclosing said cladding tubes therein and interaction between adjacent said tubular members. one and the other metallic members arranged adjacent to each other in a reactor, and reduction means for reducing a difference in swelling between said metallic members due to neutron irradiation thereto, wherein said one metallic member comprises a metallic cladding tube within which substance heated by the neutron irradiation thereto is filled, and said other metallic member comprises a tubular member enclosing a plurality of said cladding tubes therein, and said reduction means comprise solid or hollow coolant refusing members arranged in coolant flowing paths positioned between said tubular member and said cladding tubes adjacent said tubular member, and wherein said solid or hollow refusing members are arranged only adjacent said tubular member so as to decrease a total area of coolant paths adjacent said tubular member and to reduce the flow rate of coolant thereat and thereby provide an increase in temperature of the tubular member. 2. A structural component for constituting a reactor core, according to claim 1, wherein said reduction means comprise means for relatively reducing the swelling of both of said metallic members. 3. A structural component for constituting a reactor core, according to claim 2, wherein said one metallic member comprises a metallic cladding tube within which substance heated by the neutron irradiation thereto is filled, and said other metallic member comprises a tubular member enclosing a plurality of said cladding tubes therein, and said reduction means are constituted by material of said tubular member having an irradiation temperature where the swelling rate of the material due to the neutron irradiation becomes maximum and that differs from that of material of said cladding tube. 4. A structural component for constituting a reactor core, according to claim 3, wherein said cladding tube is made of such a material that an irradiation temperature where the swelling rate of said material due to the neutron irradiation thereto becomes maximum is lower than said irradiation temperature where the swelling rate of the material of said tubular member due to the neutron irradiation thereto becomes maximum. 5. A structural component for constituting a reactor core, according to claim 3, wherein the material of said cladding tube comprises a steel to which austenite stabilizing elements are added, and the material of said tubular member comprises a steel to which stabilizing elements are not added. 6. A structural component for constituting a reactor core, according to claim 3, wherein the material of said cladding tube comprises ferrite steel, and the material of said tubular member comprises austenite steel. 7. A structural component for constituting a reactor core, according to claim 3, wherein other structure made of material similar to that of either of said cladding tube or said tubular member is arranged between said cladding tube and said tubular member. 8. A structural component for constituting a reactor core, according to claim 1, wherein said one metallic member comprises a metallic cladding tube within which substance heated by the neutron irradiation thereto is filled, and said other metallic member comprises a tubular member enclosing a plurality of said cladding tubes therein, and said reduction means comprise solid or hollow coolant refusing members arranged in coolant flowing paths positioned between said tubular member and said cladding tubes adjacent said tubular member. 9. A structural component for constituting a reactor core, according to claim 8, wherein said cladding tube and said tubular member are made of materials of the same kind. 10. A structural component for constituting a reactor core, according to claim 1, wherein said one metallic member comprises a metallic cladding tube within which nuclear fuel material comprising fissile material and fertile material as substance heated by the neutron irradiation thereto is filled, and said other metallic member comprises a tubular member enclosing a plurality of said cladding tubes therein. 11. A structural component for constituting a reactor core, according to claim 10, wherein said reduction means are constituted by material of said tubular member having an irradiation temperature where the swelling rate of the material due to the neutron irradiation becomes maximum and that differs from that of material of said cladding tube. 12. A structural component for constituting a reactor core, according to claim 10, wherein said reduction means comprise to increase enrichment of the fissile material filled within said cladding tubes adjacent said tubular member more than that of the fissile material filled within said cladding tubes positioned not adjacent said tubular member. 13. A structural component for constituting a reactor core, according to claim 12, wherein said cladding tube and said tubular member are made of materials of the same kind. 14. A structural component for constituting a reactor core, according to claim 1, wherein said one metallic member comprises a metallic cladding tube within which nuclear fission reaction controlling material comprising neutron absorbing material as substance heated by the neutron irradiation thereto is filled, and said other metallic member comprises a tubular member enclosing a plurality of said cladding tubes therein. 15. A structural component for constituting a reactor core, according to claim 14, wherein said reduction means are constituted by material of said tubular member having an irradiation temperature where the swelling rate of the material due to the neutron irradiation becomes maximum and that differs from that of material of said cladding tube. 16. A structural component for constituting a reactor core, according to claim 14, wherein a guide tube made of material having an irradiation temperature where the swelling rate of the material due to the neutron irradiation becomes maximum and that is higher than that of material of said cladding tube is arranged around said tubular member. 17. A core or a reactor, comprising a plurality of said structural component according to any one of claims 1 to 16 at least. 18. A structural component for constituting a reactor core, comprising: 19. A structural component for constituting a reactor core according to claim 12, wherein said cladding tubes adjacent said tubular member having an increased enrichment of the fissile material with respect to the enrichment of the fissile material filled within said cladding tubes positioned non-adjacent said tubular member so as to enable an increase in temperature of coolant flowing in coolant paths adjacent said tubular member and therewith an increase in the temperature of said tubular member. 20. A structural component for constituting a reactor core according to claim 14, wherein said one metallic member and said other metallic member form a control rod arranged for movement with respect to said reactor core.
056028857	claims	1. A method for inspection of fuel rods, comprising a hollow tube and a plug welded to the hollow tube along a circumferential girth weld in a plane perpendicular to a longitudinal axis of the tube, the method comprising the steps of: feeding the tube to an inspection station; illuminating the tube at the inspection station; rotating the tube about said axis for at least one full revolution; collecting a matrix of reflectance data encompassing the girth weld during said rotating step, the matrix of reflectance data comprising numeric reflectance values of rows of pixels along a longitudinal length of the tube exceeding a longitudinal dimension of said girth weld, and columns of pixels around circumferences of the tube within said longitudinal length; defining a minimum defect size of pixels in the girth weld, measured by a predetermined number of adjacent pixels in at least one of the rows and the columns; determining an average of the reflectance values of at least a subset of the pixels; comparing the average of the reflectance values of said pixels in the girth weld and respective adjacent pixels to at least one of a maximum and minimum reflectance standard; and accepting and rejecting the fuel rod based on a result of said comparing step. a tube handling system operable for feeding the tube to an inspection station and relatively rotating the tube at the inspection station about said axis, for at least one full revolution; means for illuminating the tube at the inspection station; a line scan camera coupled to a digitizer and a memory, for collecting a matrix of reflectance data encompassing the girth weld during relative rotation of the tube and the camera, the matrix of reflectance data comprising numeric reflectance values of rows of pixels along a longitudinal length of the tube exceeding a longitudinal dimension of said girth weld, and columns of pixels around circumferences of the tube within said longitudinal length, the columns of pixels representing successive scans of the line scan camera during relative rotation of the tube; numerical processing means coupled to at least one of the digitizer and the memory, the processing means determining an average of the reflectance values of the pixels at least for a predetermined number of adjacent pixels in the girth weld, determining at least one of a maximum and minimum reflectance value as a proportion of the average, and comparing the reflectance values of said pixels and to at least one of a maximum and minimum reflectance standard; the numerical processing means counting a number of adjacent pixels outside the at least one of a maximum and minimum reflectance standard, and comparing said number of adjacent pixels to a maximum count, for acceptance and rejection of the tube. 2. The method of claim 1, wherein said determining of the average of the reflectance values includes averaging the reflectance values of the pixels in the matrix. 3. The method of claim 1, wherein said collecting includes repetitively digitizing an output of a line scan camera viewing a longitudinal portion of the tube including the girth weld. 4. The method of claim 3, wherein said collecting and digitizing are synchronized with rotation of the tube to provide line scans at angularly spaced positions. 5. The method of claim 1, further comprising calculating at least one of the maximum and minimum reflectance standard as a proportion of the average of the reflectance values and wherein said comparing includes comparing the reflectance values to said at least one of the maximum and minimum reflectance standard and counting adjacent pixels exceeding or not meeting the reflectance standard, respectively. 6. The method of claim 5, wherein said collecting, determining and comparing steps are conducted substantially contemporaneously. 7. The method of claim 5, further comprising defining a maximum number of adjacent pixels exceeding or not meeting the reflectance standard, and selecting and rejecting at least partly on a number of such adjacent pixels counted. 8. The method of claim 7, further comprising defining different maximum numbers of adjacent pixels in mutually perpendicular directions in the matrix. 9. An apparatus for inspection of fuel rods comprising a hollow tube and a plug welded to the hollow tube along a circumferential girth weld in a plane perpendicular to a longitudinal axis of the tube, the apparatus comprising: 10. The apparatus of claim 9, wherein the numerical processing means is operable to count said adjacent pixels outside the at least one of the maximum and minimum reflectance standard, in mutually perpendicular directions in the matrix. 11. The apparatus of claim 10, wherein said adjacent pixels outside the at least one of the maximum and minimum reflectance standard are counted by the numerical processing means in rows corresponding to line scans and in columns corresponding to successive line scans. 12. The apparatus of claim 11 wherein the numerical processing means applies a different maximum count in the mutually perpendicular directions for profiling a maximum defect size relative to a direction of extension of the pixels.
	claims	1. A method for producing spherical fuel and/or breeder material cores having a size in the range between 300 μm and 800 μm, for producing cores made of uranium oxide and/or uranium carbide and/or a uranium containing mixed oxide and/or mixed carbide by dripping a solution containing a uranyl nitrate, as well as auxiliary agents in the form of tetrahydrofurfuryl alcohol and polyvinyl alcohol in an ammoniacal precipitation bath for the formation of microspheres; aging the microspheres in an ammoniacal aging water; washing the microspheres; and drying as well as a thermal treatment of the microspheres,characterized in that the microspheres are separated from the ammoniacal precipitation bath via a first separator, and for aging, led to the ammoniacal aging water, wherein the time period within which the microspheres are in contact with the ammoniacal precipitation bath up to the contact with the ammoniacal aging water, is the same, or approximately the same for each microsphere by means of the first separator; the microspheres are transferred via a transfer device from the ammoniacal aging water to a multistage cascade scrubber, in which the microspheres are washed until they are free, or substantially free, of ammonium nitrate, and at least one of the auxiliary agent contained in the microspheres; and after the drying of the microspheres, the latter are calcined and distributed in a monolayer during a thermal treatment. 2. The method according to claim 1, characterized in that the ammoniacal aging water is set to equilibrium conditions in such a way that every, or substantially every, microsphere with respect to components, in each case, presents a same or substantially a same concentration. 3. The method according to claim 2, characterized in that equilibrium conditions are set, in the ammoniacal aging water, at least with respect to ammonium nitrate and/or urea contained in the microspheres. 4. The method according to claim 2, characterized in that equilibrium conditions are set, in the ammoniacal aging water, at least with respect to the tetrahydrofurfuryl alcohol contained in the microspheres. 5. The method according to claim 2, characterized in that, after removal of the microspheres from the ammoniacal aging water, the concentration of at least tetrahydrofurfuryl alcohol in the microspheres is equal to, or approximately equal to, the one in the ammoniacal aging water. 6. The method according to claim 2, characterized in that, after removal of the microspheres from the ammoniacal aging water, a concentration of ammonium nitrate, ammonium hydroxide, and if the content includes urea, of urea in the microspheres is equal to, or approximately equal to, the one in the ammoniacal aging water. 7. The method according to claim 1, characterized in that in the ammoniacal aging water, conditions are set which allow an exchange of at most 15 wt %, with H2O. 8. The method according to claim 1, characterized in that the microspheres are transferred into the ammoniacal aging water which has been set to room temperature, subsequently heating to a temperature T1 with 60° C.≦T1≦80° C. is carried out, the microspheres remain for a time t with 50≦min≦t≦70 min at the temperature T1 in the ammoniacal aging water, and after the time t, the ammoniacal aging water is cooled to room temperature, and the microspheres are then removed. 9. The method according to claim 8, characterized in that the heating and cooling of the ammoniacal aging water is carried out by means of at least one heat exchanger. 10. The method according to claim 1, characterized in that the microspheres are led in the multistage cascade scrubber through several wash stages. 11. The method according to claim 10, characterized in that a sinking speed of the microspheres in each wash stage is set by washing water which flows in a circulation in each wash stage. 12. The method according to claim 10, characterized in that washing water of the wash stage is supplied via an annular gap, with adjustable separation, which is present in the bottom of a funnel. 13. The method according to claim 11, characterized in that, besides the washing water which is led in circulation in each wash stage, washing water is led through all the cascades starting from a bottommost cascade. 14. The method according to claim 13, characterized in that, as washing water supplied to the bottommost cascade, weakly ammoniacal water is used. 15. The method according to claim 13, characterized in that, as washing water supplied to the bottommost cascade, two molar ammoniacal water is used. 16. The method according to claim 1, characterized in that the washed microspheres are dried in a continuous belt furnace at a temperature T2 with T2≦120° C. 17. The method according to claim 16, characterized in that the washed microspheres are evenly distributed with washing water via a feed device, on a conveyor element conveyed through the continuous belt furnace. 18. The method according to claim 17, characterized in that the microspheres are applied to a strainer belt or the conveyor element. 19. The method according to claim 17, characterized in that a detergent is added to the washing water before the supplying on the conveyor element. 20. The method according to claim 19, characterized in that a water-soluble fatty alcohol is used as detergent. 21. The method according to claim 16, characterized in that the dried microspheres, after passing through the continuous belt furnace, are conveyed by a conveyor from which the microspheres are removed by means of an aspiration device, and are then separated in a cyclone, and collected in a reservoir. 22. The method according to claim 1, characterized in that the microspheres in the monolayer are conveyed in metal shells which present openings on a bottom side and are conveyed through a continuous furnace, and calcined at a temperature T3 with T3≦450° C. 23. The method according to claim 16, characterized in that the microspheres in the continuous belt furnace, pass through several heating zones with at least one drying zone and at least one calcination zone. 24. The method according to claim 1, characterized in that the drying and/or calcination are carried out in a circulating air operation. 25. The method according to claim 22, characterized in that the calcined microspheres are aspired from the metal shell. 26. The method according to claim 25, characterized in that the aspired microspheres are separated in a cyclone and collected in a reservoir. 27. The method according to claim 16, characterized in that the temperature T2 is 100° C.≦T2≦120° C. 28. The method according to claim 22, characterized in that the temperature T3 is 160° C.≦T3≦430° C. 29. The method according to claim 22, characterized in that the microspheres are calcined in two steps. 30. The method according to claim 7, characterized in that in the ammoniacal aging water, conditions are set which allow an exchange of 10-15 wt % THFA, with H2O.
047028831	summary	CROSS REFERENCE TO RELATED APPLICATIONS Reference is hereby made to the following copending applications dealing with related subject matter and assigned to the assignee of the present invention: 1. "Reconstitutable Nuclear Reactor Fuel Assembly With Unitary Removable Top Nozzle Subassembly" by John M. Shallenberger, assigned U.S. Ser. No. 673,681 and filed Nov. 20, 1984, a continuation-in-part of U.S. application Ser. No. 457,790, filed Jan. 13, 1983. 2. "Improved Top Nozzle And Guide Thimble Joint Structure In A Nuclear Fuel Assembly" by John F. Wilson et al., assigned U.S. Ser. No. 711,433 and filed Mar. 13, 1985. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to fuel assemblies for nuclear reactors and, more particularly, is concerned with improved features for removably attaching the top nozzle on the guide thimbles of a fuel assembly for facilitating reconstitution thereof. 2. Description of the Prior Art Conventional designs of fuel assemblies include a multiplicity of fuel rods held in an organized array by grids spaced along the fuel assembly length. The grids are attached to a plurality of control rod guide thimbles. Top and bottom nozzles on opposite ends of the fuel assembly are secured to the control rod guide thimbles which extend above and below the opposite ends of the fuel rods. At the top end of the fuel assembly, the guide thimbles are attached in openings provided in the top nozzle. Conventional fuel assemblies also have employed a fuel assembly hold-down device to prevent the force of the upward coolant flow from lifting a fuel assembly into damaging contact with the upper core support plate of the reactor, while allowing for changes in fuel assembly length due to core induced thermal expansion and the like. Such hold-down devices have included the use of springs surrounding the guide thimbles, such as seen in U.S. Pat. No. 3,770,583 (U.S. Pat. No. Re. 31,583) and U.S. Pat. No. 3,814,667 to Klumb et al. and U.S. Pat. No. 4,269,661 to Kmonk et al. During operation of such assembly in a nuclear reactor, the fuel rods may occasionally develop cracks along their length resulting primarily from internal stresses, thus establishing the possibility that fission products having radioactive characteristics may seep or otherwise pass into the primary coolant of the reactor. In view of the high costs associated with replacing fuel assemblies containing failed fuel rods, both domestic and foreign utilities have indicated an interest in reconstitutable fuel assemblies in order to minimize their operating and maintenance expenses. Conventional reconstitutable fuel assemblies incorporate design features arranged to permit the removal of individual failed fuel rods, the option to replace rods, followed by the additional use in the reactor and/or normal handling and storage of the affected fuel assembly. Reconstitution has been made possible by providing a fuel assembly with a removable top nozzle. The top nozzle is mechanically fastened usually by a threaded arrangement to the upper end of each control rod guide thimble assembly, and the top nozzle can be removed remotely from an irradiated fuel assembly while it is still submerged in neutron-absorbing liquid. With rod removal/replacement and after the top nozzle has been remounted on the control rod guide thimbles, the reconstituted assembly can then be reinserted into the reactor and used until the end of its useful life, and/or stored in spent fuel pools or other places in a safe, normal manner. The above-cross referenced patent applications describe and illustrate reconstitutable fuel assemblies having different arrangements for removably attaching the top nozzle to the upper ends of the guide thimbles. When given the task to modify a preexisting fuel assembly wherein the top nozzle is not readily removable, prior top nozzle removable attachment arrangements such as those of the cross-referenced applications are instructive of possible approaches, but do not necessarily point toward the direction one should take to make the required modification in the simplest and least costly way. Consequently, a need exists for a fresh approach tailored to the particular preexiting top nozzle attachment structure, one which will achieve removability of the top nozzle with the minimum change in the design of preexisting parts. SUMMARY OF THE INVENTION The present invention provides improved features designed to make a preexisting top nozzle attachment structure removable in a manner which satisfies the aforementioned needs. In the preexisting structure, axially extending recesses having upper and lower ledges were machined into the upper portions of the guide thimble extensions and received radial pins inserted in the upper hold-down plate of the top nozzle to form an upper limit to hold-down plate travel and to support the weight of the fuel assembly during lifting. In order to remove the top nozzle, these pins had to be removed which was a tedious operation. The present invention introduces a simple change to each of the guide thimble extensions which makes the upper hold-down plate and thus the top nozzle readily removable from the guide thimbles. The upper end of each guide thimble extension is modified to form a removable stop which defines the upper ledge of the recess. Each stop interacts with one of the hold-down plate radial pins to form the upper limit for travel of the hold-down plate along the respective guide thimble extension. The lower portion of the stop having a reduced diameter compared to the upper portion thereof is externally threaded in order to be threadably received into an internally threaded section on the upper end of the remainder of the guide thimble extension. By unthreading the stop from the respective guide thimble extension, the upper hold-down plate can be removed form the guide thimbles. Accordingly, the present invention is provided in a nuclear fuel assembly having at least one control rod guide thimble and a top nozzle, wherein the guide thimble includes an upper extension member and the top nozzle includes an upper hold-down plate having a passageway slidably receiving an upper end portion of the extension member. The present invention is directed to an improved structure for removably attaching the upper hold-down plate on the guide thimble upper extension member. The improved attaching structure basically comprises: (a) means defining a recess on the upper end portion of the extension member; (b) a stop member having upper and lower portions, with the stop member lower portion adapted to connect on the extension member upper end portion and the stop member upper portion having an outside diameter greater than that of the stop member lower portion and extending above the extension member upper end portion when the stop member lower portion is connected on the same, and the stop member also having a ledge formed thereon at a transition between its upper and lower portions which defines an upper limit of the recess when the stop member is connected on the extension member upper end portion; and (c) an element mounted in the upper hold-down plate and extending therefrom into the passageway of the plate and the recess of the extension member upper end portion, with the element being positioned to slide upwardly along the recess until making engagement with the ledge on the stop member when the stop member is connected on the extension member upper end portion for limiting upward movement of the upper hold-down plate along the guide thimble and the element being positioned to slide upwardly along and past the recess when the stop member has been disconnected from the extension member upper end portion for allowing removal of the upper hold-down plate from the guide thimble. More particularly, the upper end portion of the extension member has means defining a threaded section on the interior thereof, whereas the stop member lower portion has a complementary threaded section defined on the exterior thereof adapted to threadably fit into the threaded section of the extension member upper end portion for releasably connecting the stop member on the guide thimble extension member. Further, the recess terminates at an upper terminal edge of the guide thimble extension member upper end portion. These and other advantages and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
048266485	description	DESCRIPTION OF PREFERRED EMBODIMENT A neutron absorbing bar as described may be used in present day reactors as well as in spectrum shift reactors still in the design stage. It may, for example, be used in combination with a fuel assembly as disclosed in European Patent No. 159 509 already mentioned or with a fuel assembly as described in French Patent No. 84 19917. Referring to FIG. 1, the relative position of the pommel or hub 8 of an absorbant bar and of the elements which it contains is shown when the bar is separated from its drive shaft and rests on a bearing surface 10 which will be assumed to be the upper core plate of a reactor (but which could be the upper end nozzle of a fuel assembly). Pommel 8 and radial fins 12 connected thereto constitute a unit generally called "spider". The arms 12, formed as thin vertical vanes, carry vertical rods 14 which, in the position in which the pommel is shown, are completely engaged in guide tubes of one or more fuel assemblies. The drive shaft (not shown) has a conventional gripper whose fingers may be spread out for engagement into an upper internal recess 46 of the pommel. The damping device incorporated in pommel 8 may be considered as including three parts, namely a hydraulic brake, a damper or "dashpot" for attenuating the initial shock and an end-of-travel load absorbing coil spring. The hydraulic brake comprises a cylinder formed in the sleeve and closed at its upper end. A hollow piston 18 is slidably sealingly received in the bore 16 of the cylinder. The piston 18 has a transverse wall 19 supporting resilient return and damping means 20. As shown, the resilient means consist of two helical springs in series relation, having opposite winding directions to avoid rotational effects. The two springs 20 are guided by a central rod 22 fixed to the bottom wall of the cylinder. The cylindrical wall of the cylinder is formed with openings 24 for throttling the water flow forced out of the cylinder by piston 18. The openings are spaced apart along the cylinder. They are distributed in a longitudinal plurality of sets (for example each of two holes) to balance the hydrodynamic transverse thrusts due to the water jets which during movement of the piston are forced out of the cylinder. The number of sets will depend on the desired progressivity, taking into account the difference in conditions when the coolant is cold and when hot. In practice, sixteen sets will generally be sufficient. Piston 18 advantageously has a downwardly directed radial shoulder 26 between a portion which has a sliding fit in the cylinder and a portion which has an annular clearance. The shoulder 26 is at such a distance from the lower end of the piston that the clearance communicates with the lower sets of openings 24 even when the bar is completely inserted in the core (FIG. 1), for providing a cooling water flow. The extent of downward travel of piston 18 is limited by a stop ring 28 housed in an internal groove of the cylinder. As shown in FIG. 1, the pommel has at its lower part a slot 30 for easier access to the stop ring 28. The ring may be welded in position. The purpose of the shock damper is to attenuate the shock of piston 18 upon bar fall. The damper has a plunger 32 slidable in a blind bore formed in the piston below the dividing wall 19. A reset spring 36, of low stiffness as compared with spring 20, biases the plunger 32 downwardly against a stop ring 38. A restricted hole (or holes) 34 formed in the wall of the piston opposes a calibrated head loss to flow of liquid driven out by plunger 32 upon impact. A single hole has been shown in FIG. 1, but in general several holes will be provided with such a spacing that the impact speed of piston 18, when the plunger 32 is completely retracted, is reduced to as low a value as possible. Finally, an end-of-travel spring 40 is retained between the bottom of the cylinder and a flanged thimble 42 on which the resilient means 20 also rest. The flanged thimble 42 has a longitudinal size such that the piston 18 comes in abutment thereagainst at the end of travel of the hydraulic brake. The compression of spring 20 absorbs the residual momentum of the bar after hydraulic braking. One or more openings 44 may be provided in the cylinder for allowing the liquid to flow out of the cylinder during the upward movement of flanged thimble 42. When the pommel bears on the core-plate, as shown in FIG. 1, the plunger 32 is completely retracted in the piston. The latter projects by a slight amount, retained by the compression force exerted by the end-of-travel spring 40. The device operates as follows: As long as the bar is connected to its drive shaft, plunger 32 is held down in abutment against ring 38 by spring 36. The shoulder 26 of piston 18 is held in abutment against the stop ring 28 by springs 20. The springs 20 are prestressed such that the piston 18 remains in abutment against ring 28 despite inertial forces generated by the step-by-step control of the bar drive mechanism, which frequently causes accelerations reaching 15 g. It will generally be sufficient for the spring 20 to have a prestressing at rest of about 20 daN, if the weight of piston 18 is low enough. Finally, the end-of-travel spring 40 is completely relaxed. During a first phase of operation, only the shock damper of the dashpot acts: from the time that plunger 32 comes into contact with core plate 10 (FIG. 2A), the plunger is moved into the piston 18 and drives liquid through the openings 34. At the end of the first phase (FIG. 2B) the piston 18 comes into contact with plate 10. During the second phase, piston 18 moves along the cylinder, compresses springs 20 and drives out water from the cylinder through the openings 24 (not shown in FIGS. 2A-2E) which oppose a pressure drop which increases as the piston moves (FIG. 2C). The second operating phase ends when piston 18 comes into abutment against flange 42 (FIG. 2D) and begins to compress the end-of-travel spring 40. Continued penetration of piston 18 causes spring 40 to compress until complete damping is obtained (FIG. 2E). The openings 24 may all be located above the arms in which case they may be drilled after the arms have been screwed to the cylinder.
	description	This application is a continuation in part of U.S. patent application Ser. No. 15/167,737 filed on May 27, 2016 and entitled Energy Beam Propulsion System, and issued as U.S. Pat. No. 9,938,026 on Apr. 10, 2018, which is a continuation in part of U.S. patent application Ser. No. 15/167,737 filed on May 27, 2016 and entitled High Energy Beam Diffraction Material Treatment System and issued as U.S. Pat. No. 9,711,252, on Jul. 18, 2017, which claims the benefit of U.S. patent application Ser. No. 14/925,970, filed on Oct. 28, 2015, entitled Neutron Beam Diffraction Material Treatment System and issued as U.S. Pat. No. 9,508,460 on Nov. 29, 2016, which is a continuation in part of U.S. patent application Ser. No. 14/525,506, filed on Oct. 28, 2014, entitled Neutron Beam Regulator and Containment System, and now issued as U.S. Pat. No. 9,269,470 on Feb. 23, 2016; the entirety of all applications listed above are incorporated by reference herein. The present invention relates to coherent beam treatment system that produces a first and second energy beam that are coherent at a treatment location. High energy beams are used for a wide variety of treatment applications including material treatment, such as the treatment of plastics and metals, and organic tissue treatment, such as the treatment of tumors. High energy beams include acoustic beams or waves, neutron beams, proton beams, lasers, and x-rays, that may be defined by a wave. In many treatment applications, a beam is passed through a person's body to a treatment location. The beam passes through the body and is incident on the treatment location, such as a tumor. All of the tissue that the beam passes through is being exposed to the high energy beam and this may not be desirable. In other applications, a first and second beam may be configured to intersect at a treatment location, as described in U.S. patent application Ser. No. 14/525,506, filed on Oct. 28, 2014, entitled Neutron Beam Regulator and Containment System. The beams may diffract and the diffraction may increase the effectiveness of the treatment. High energy beam may be used in a variety of applications including analytical methods, cancer treatment and to treat or condition various materials. For example, neutron beams are used for scattering and diffraction material analysis of material properties and particularly the crystallinity of a material. The highly penetrating nature of neutron beams may be used in the treatment of cancerous tumors. Another use of neutron beams may be to treat materials, and particularly metals, wherein neutron bombardment lodges neutrons into the metal to effectively harden the metal. Neutron bombardment can create point defects and dislocations that stiffen or harden the materials. These and other uses of neutron beams can potentially expose people to neutron radiation and neutron activation, the ability of neutron radiation to induce detrimental high energy in body tissue or other substances and objects exposed thereto. Currently energy beams are employed for treatment of materials and tissues. The capability to create a wave like interference pattern requires multiple beams. An interference pattern may be modified depending on the desired application. Neutron beam radiation protection generally utilizes radiation shielding, or placing a material around the beam, beam source and target that absorbs neutrons. Common neutron shielding materials include high molecular weight hydrocarbons such as polyethylene and paraffin wax, as well as concrete, boron containing materials including boron carbide, boron impregnated silica glass, borosilicate glass, high-boron steel, and water and heavy water. These shielding materials have varying levels of effectiveness and can become radioactive over time, thereby requiring them to be changed out. In addition, a shield may not be installed or properly positioned during use of a neutron beam, thereby exposing workers and the surrounding environment to neutron radiation. Neutrons can be guided by a vacuum tube having an inner surface coated with a neutron reflector, such as nickel. This reduces the loss of neutrons through scattering of the beam. Although neutron guides can transport neutron beams, they do not act to focus or reduce beam divergence. Magnetic fields can be used to affect a neutron beam shape, intensity, velocity, direction and polarization. Magnetic fields generated by an electrical current running through a coil, for example, may be used to direct, intensify and contain a neutron beam. However, a neutron beam source, such as a neutron beam generator, may be operated independently of an electrical current generated magnetic field configured to direct and otherwise contain a neutron beam, leaving the system susceptible to operating in an unsafe condition when no other containment system is employed. Materials or parts hardened through neutron bombardment may only require hardening over a particular area, or a higher degree of hardening in a particular region of the part. Current neutron bombardment systems provide a uniform dosing of neutrons to the material or part and do not enable a gradient of hardening. The present invention describes a coherent beam treatment system that produces a first and second energy beam that are coherent at a treatment location. An energy beam, as used herein, includes a neutron beam, a proton beam, an electron beam, acoustic waves, a laser and x-ray. A high energy beam, or simply beam used herein, may be defined by a wave, such as a sinusoidal wave having a frequency and amplitude. The present invention provides a control system for creating coherence between a first and second beam at a treatment location. Coherence is a location where two waves have matching wave profiles. As an example, coherence between two waves wherein a first wave has a frequency that is double that of the second wave occurs at every other peak of the first wave. A wave may be defined by a simple sinusoidal equation wherein the frequency and amplitude are constant as a function of time. The present invention may regulate one of both beams to be defined by a complex wave equation, wherein the frequency and/or amplitude change as a function of time. A complex wave may be the culmination of two or more wave equations, as defined by Fourier Transform, for example. A control system of the present invention may regulate one or both beams to be coherent at a treatment location and may modify the location of coherence to allow treatment over a treatment area. The Fourier transform is called the frequency domain representation of an original signal or wave. The term Fourier transform refers to both the frequency domain representation and the mathematical operation that associates the frequency domain representation to a function of time. A Fourier transform may define a wave form that changes amplitude and/or frequency as a function of time and this is referred to herein as a complex wave form, and the equation defining the wave form is defined as a complex wave form equation. A complex wave equation may be combination of two or more wave equations. The control system may employ a computer program that utilizes complex wave equations, Fourier transforms and the like to produce a high energy beam that is a complex wave, as defined herein. In an exemplary embodiment, a coherent beam treatment system produces a first energy beam having a first frequency and a first direction and a second energy beam having a second frequency and a second direction. The control system comprises a beam regulator configured to adjust the frequency of the first beam and/or second beam to create first and second beam coherence at a treatment location. The control system may comprise an actuator that changes the direction of the first and/or second beam being emitted, and therefore may change the location of coherence. In this way, an area over a treatment location may be treated by movement of one or more of the beam. An actuator may rotate a beam and a direction of a second beam may be kept constant, thereby changing the location of intersection of the two beams along the length of the second beam. In addition, the control system may regulate first or second beam, such that the location of coherence corresponds substantially with the location of intersection of the two beams. A beam regulator may receive input from a microprocessor that regulates a beam's frequency and/or amplitude as a function of time. A beam may be defined by a complex wave, wherein the amplitude and/or frequency change as function of time. The wave equation may be the culmination of two or more simple wave equations, each with their own frequency and amplitude. Fourier Transform may be utilized by a control system program to provide instruction to the regulator to control the wave produced. A first high energy beam may be substantially different from a second energy beam, wherein a first energy beam has a frequency and/or amplitude that is at least 20% different than the second energy beam. A first high energy beam may an amplitude and or frequency that is different from a second high energy beam by about 20% or more, about 30% or more, about 50% or more, about 100% or more, about 200% or more, about 500% or more and any range between and including the difference percentage provided. In an exemplary embodiment, the first energy beam has an amplitude and/or frequency that is at least twice that of the second energy beam. The first and second beams may be substantially different at a treatment location or at a location of coherence. In one embodiment, the first and second beams are defined by a simple wave equation, having a constant frequency and amplitude as a function of time. In another embodiment, one of the first or second energy beams are defined by a simple wave equation and the other is defined by a complex wave equation, again, having a change in amplitude or frequency as a function of time. In still another embodiment, both the first and second energy beams are defined by a complex wave equation. In an exemplary embodiment, a coherent beam treatment system comprises a first and a second beam generator, wherein at least one has a beam regulator. In another embodiment, both the first and second beams generators are configured with a beam regulator to change the frequency and/or amplitude of the beams. In still another embodiment, a beam generator produces an input beam that is then split by a beam splitter into a first split beam and second split beam. The first and/or second split beams may travel from the beam splitter to a reflector, that directs the first and second beams to intersect or substantially align at a treatment location. Substantially align, as used herein, means that the first and second beams are close enough to have coherence. A beam splitter may incorporate one or more prisms and a reflector may comprise a mirror. In an exemplary embodiment, a second split beam is reflected by a mirror and is directed toward a treatment location. A split beam may be further regulated by a beam regulator. For example, a split beam may be regulated by a beam regulator that is configured after the reflector, or mirror. An exemplary coherent beam treatment system comprises a user interface. The user interface may allow a user to set or input a treatment location, may enable an input of power output of the energy beams, may enable input of treatment time or protocol. A treatment location may be identified on a mapped area, such as an x-ray of a person body. For example, treatment location may be identified on an X-ray or other image produced by an imaging technique. The control system may then automatically control the beams to be coherent at the treatment location, or in an area around the treatment location. A user may outline a treatment location and the control system may generate coherence of the two beams over the outlined treatment location. Furthermore, beams may be affected by a material that the beam has to pass through and the user interface may enable an input of a material type and the control system may automatically adjust the beams to effectively pass through the material and be coherent at a treatment location. A high energy beam may be a proton beam, neutron beam, laser or X-rays. The type of high energy beam used may be selected for the best effectiveness of the treatment desired. The present invention provides for a method of treating a treatment location by creating high energy beam coherence at said treatment location, as described herein. The treatment location may be a surface of a material, such as a metal or plastic. In another embodiment, the treatment location is organic material, such as a part of a body, human or animal. In an exemplary embodiment, a treatment location is a tumor and the treatment destroys the tumor or sufficiently damages the tumor tissue to destroy the viability of cells therein. For cancer tumor treatment, the high energy beams described herein provide a treatment option that does not require radiation, or a radioactive source. This eliminates the risk of loss of a radioactive material that may be used in terrorist activity. In an exemplary embodiment, a beam reflector/splitter may be placed in the path of a high energy beam to create a reflected beam that can be used to create diffraction and interference patterns with the source beam. The invention is directed to a neutron beam diffraction treatment system and method of treating a work-piece. In an exemplary embodiment, a neutron beam diffraction material treatment system comprises a first neutron beam source configured to produce a first neutron beam having a first direction and a second neutron beam source configured to produce a second neutron beam having a second direction, wherein the second neutron beam intersects with the first neutron beam at an intersecting point and whereby the first and second beams are diffracted as a result of intersecting each other. In an exemplary embodiment, the intersecting point of the diffracted beams is located on a within a work-piece to treat the work-piece. The work-piece may be treated by neutron entrapment or through localized heating. The intersecting point may be configured to move on or within the work-piece such as by movement of the workpiece by an actuator, or by controlled movement of the first and second neutron beams or coordinated actuation. The intensity of the first and or second neutron beams may be change or varied in a modulating manner to produce a changing treatment intensity. One or more magnetic coils may extend around the neutron beam from the neutron beam source, or outlet of the source, to the work-piece or target. The intensity of the magnetic field may be changed or modulated to affect the neutron beam and thereby modulate the neutron beam or the diffraction properties. A magnetic coil may also be used to ensure containment of the neutron beam, as described further herein. A work-piece may be plastic and work-piece treatment may include localized heating of the plastic surface or a portion within work-piece, such as below the surface. A work-piece may be metal, or metal alloy and treatment of the work-piece may include neutron entrapment. An exemplary neutron beam diffraction material treatment system may comprise a magnetic coil configured to extend around one or each of the neutron beam and may be configured to extend around both of the neutron beams. A magnetic coil may extend from the neutron beam source to the work-piece or work-piece station and thereby contain the neutron beam. The magnetic coil may be a continuous magnetic coil or a discrete magnetic coil. In one embodiment, a magnetic coil extends around both of the neutron beams. The magnetic field produced by the magnetic coil may be configured with a power control system to ensure that the neutron beam will not operate unless the magnetic field is activated and operational, thereby ensuring containment of the neutron bean. In an exemplary embodiment, the magnetic field strength on the neutron bean is changed or modulated as a function of time. This may be accomplished by changing the strength of the magnetic field produce, such as by the amount of current drawn by the magnetic coil or by changing a position of the magnetic coil with respect to the neutron beam. The magnetic coil may be moved or oscillated to vary the magnetic field on the neutron beam, for example. Neutrons have a magnetic moment and can be affected by exposure to magnetics fields. The shape, intensity, velocity, direction and polarization of a neutron beam can be manipulated through magnetic field exposure. In an exemplary embodiment, a neutron beam regulator, or the present invention, comprises a magnetic coil configured around a neutron beam between a neutron beam source and a target. A magnetic coil may extend substantially the entire distance between a neutron beam source, or outlet of the beam source, and a target. In an exemplary embodiment, a magnetic coil is configured to extend at least partially around a neutron beam source to further contain and direct the neutrons and thereby reduce neutron radiation exposure outside proximal to the beam source. In another exemplary embodiment, a magnetic coil is configured to extend at least partially around a target. For example, a target may be configured to fit within a work piece station and a magnetic coil may extend around a portion of the work-piece station. A work-piece station may be configured to index in and out of a magnetic coil, whereby a work-piece can be loaded into the work-piece station and then positioned at least partially with the magnetic coil or magnetic field produced by the coil. Again, configuring the magnetic coil and/or directing the field around a work-piece will further contain and direct the neutrons and thereby reduce neutron radiation proximal to the target or outside of a target area. In an exemplary embodiment, a neutron beam regulator comprises a power control system that is configured as a safety system to ensure that the neutron beam is not operational unless a containing magnetic coil is powered on. An exemplary power control system comprises a magnetic coil power supply output, a neutron beam source power supply output, a magnetic coil power sensor, and a power safety feature. The power safety feature ensures that the neutron beam generator will not receive power from the power control system unless the magnetic coil is receiving power and producing a confining magnetic field, thereby effectively containing the neutron beam. A magnetic coil power supply sensor is configured to detect when the magnetic coil is operating and the power safety feature is configured to prevent power supply to said neutron beam source power supply output unless the magnetic coil power supply sensor detects that the magnetic coil is on. In embodiments with a plurality of discrete magnetic coils that may have their own coil power output, a single power supply may be configured to power each of the coil power outputs. A magnetic coil power sensor may be configured with this single power supply. The power supply to a neutron beam source power supply output may be cut-off by any suitable means including a switch that is opened in the event that the magnetic coil sensor detects that no power is being delivered to the magnetic coil(s). Any suitable type of magnetic coil may be configured around a neutron beam including a continuous magnetic coil and discrete magnetic coils. A magnetic field may be generated by electromagnets, or any suitable electrical current carrying material. In an exemplary embodiment, a magnetic coil comprises an electrically conductive wire that extends completely around the neutron beam, or 360 degrees around the beam. In some cases, a magnetic coil is configured as a discrete magnetic coil or ring that extends around the neutron beam. A discrete magnetic coil extends a portion of the neutron beam length, or distance from the neutron beam source or outlet to a target, including, but not limited to, no more than about one quarter of the neutron beam length, no more than about one third of the neutron beam length, no more than one half of the neutron beam length and any range between and including the discrete magnetic coil extension lengths. Any suitable number of discrete coils may be configured around the neutron beam including, but not limited to, 2 or more, 4 or more, 6 or more, 10 or more, twenty or more and any range between and including the number of coils provided. In another embodiment a magnetic coil is configured as a continuous coil that winds around the neutron beam in a substantially continuous manner or substantially the entire neutron beam length. A continuous coil, as defined herein, extends at least about three quarters of the neutron beam length. A magnetic coil may comprise a single continuous wire or a plurality of wires that may be bundled or otherwise configured in a coil or ring around the neutron beam. In an exemplary embodiment, a single continuous coil is configured around a neutron beam and extends from a neutron beam source to a target. In another embodiment, a plurality of discrete coils are configured along the neutron beam between the beam source and the target. The magnetic coils may be configured in any suitable manner around the neutron beam. In one embodiment, one or more discrete magnetic coils are configured proximal to the neutron beam and a continuous magnetic coil is configured around or outside of the one or more discrete magnetic coils. In this embodiment, the outer continuous magnetic coil may be configured primarily as a neutron beam containment coil to reduce neutron radiation leakage. In addition, in this embodiment, the one or more discrete magnetic coils may be independently powered by a beam modulator controller to provide a modulating magnetic field that is configured to change the properties of the neutron beam as desired. A beam modulator controller is configured to enable modulation of the electrical current to the discrete coils and therefore modulation of the magnetic field intensity or direction. For example, the magnetic field intensity of a first magnetic coil configured proximal to a neutron beam source may be higher, such as two times or more, the magnetic field intensity of a second magnetic coil configured more proximal to a target. The magnetic field may be modulated to change the shape, intensity, velocity, direction and polarization of a neutron beam. The magnetic field may be modulated to ensure a sufficient level of containment of the neutron beam depending on the neutron beam source or type, the length of the beam from the source to the target and the like. In addition, a magnetic field may be modulated to increase the amount of exposure of a particular incident surface. An incident surface may be a material for analysis, a material for hardening through the bombardment with a neutron beam, a patient tissue or cancer tumor location and the like. An incident surface may be plastic or metal or organic tissue. A neutron beam regulator may comprise a work-piece station that is configured to retain a work-piece for exposure to a neutron beam configured within a magnetic field. In an exemplary embodiment, a work-piece station is configured to move and thereby move the location of the incident neutron beam on the work-piece surface. A neutron beam regulator may be configured with a modulating magnetic coil that is configured to receive a variable power input from the beam modulator controller. The work-piece may be positioned and indexed to change the location of the incident neutron beam and the intensity of the neutron beam may be modulated to enable variable conditioning or treatment of the work-piece surface. For example, a first portion of a work-piece surface may be exposed to a higher intensity beam and therefore have a higher hardness, and a second portion of a work-piece may be exposed to a lower intensity neutron beam and have a resulting lower hardness. This combination of neutron beam intensity modulation along with work-piece positioning enables complete tailoring of work-piece treatment conditions heretofore not available. This same principle may be used to also provide specific and more precise treatment of cancerous tumors, whereby the tumor itself may be exposed to a much higher neutron beam intensity than surrounding tissue. This controlled method may reduce damage to surrounding tissue and more effectively treat a tumor. The coherence of two high energy beams may be moved by a change in the Fourier transform equations used to control one or more of the beams, or may physical movement of one or more of the beams, either by displacement or by rotation. In this way, a tumor, for example, may be subjected to coherence of the two beams over substantially the entire tumor. Higher energy may be imparted into the core of central region of the tumor than around the periphery, to reduce damage to surrounding tissue. In an exemplary embodiment, a neutron beam regulator system is configured with at least one magnetic coil that extends around a neutron beam between a neutron beam source and a target, a work-piece station and a treatment control system. A treatment control system is configured with a beam modulator controller to control the power supply to the magnetic field and therefore the intensity of the neutron beam. In addition, a treatment control system may comprise a beam location program configured to track the location of a neutron beam with respect to an incident surface, such as on a work-piece or proximal a tumor. A beam modulator controller may be configured to vary a property of a neutron beam as a function of said neutron beam location. As described, this type of system enables a tailored treatment function and this may be programmed into the treatment control system. A neutron beam regulator system comprising a treatment control system may also comprise a power control system and the treatment control system may be configured with the power control system. A one-piece unit may house both the treatment control system and the power control system. A novel method of regulating a neutron beam source is provided by any of the embodiments of the neutron beam regulator as described herein. In one exemplary method, a neutron beam source and magnetic coil are both plugged into a power control system. The power control system is powered on thereby enabling power supply to both the magnetic coil and the neutron beam generator and thereby substantially containing the neutron beam within the magnetic coil. The magnetic coil power sensor is configured to monitor the power supply to the magnetic coil and, in the event of a loss of power being drawn by the magnetic coil, the power supply to the neutron beam source will be terminated. It is to be understood that a threshold power draw level may be set for the magnetic coil power supply output and the magnetic coil power sensor may be configured to detect a power draw below this threshold level and thereby terminate power to the neutron beam source. The neutron beam regulator system, as described herein, may effectively keep neutrons outside of the containment and/or modulating magnetic coils, thereby creating an exclusion zone. In some environments, labs and processing facilities for example, it may be important to exclude any neutrons from entering into the exclusion zone as they may interfere with the neutron beam. A neutron beam system, as described in any of the embodiments herein, may be configured on a spacecraft as a neutron beam propulsion device, wherein the emission of a neutron beam from the spacecraft propels the spacecraft. The neutron beam propulsion device may comprise one or more magnetic coils around the emitted neutron beam and the magnetic coils may be discrete or may be continuous, wherein they extend from the neutron beam generator along at least a portion of the length of the beam that is 10 cm or more. The magnetic may be powered magnets or self-contained magnets. Powered magnets require electrical power to produce the magnetic field, wherein an electric current flows through the coils to produce a magnetic field of varying intensity depending on the current flow. A self-contained magnet may be a natural magnet that produces a magnetic field without the supply or electrical power and may comprises neobdium, for example. The neutron power source may be self-contained or generated, wherein electrical power is required for generate the neutron beam. A self-contained neutron beam source produces neutrons naturally such including, but not limited to, a radioactive material, Californium-252, Cesium-137 and polonium-beryllium (Po—Be). The neutrons produce naturally may form a neutron beam through the neutron beam generator. A spacecraft utilizing a self-contained neutron beam source and a self-contained magnetic coil may be a self-contained space-craft, or a space-craft requiring no external or consumable fuel supply. A self-contained spacecraft may be capable of travel through large distances of space for data gathering missions, for example. Cesium-137, or radiocaesium, is a radioactive isotope of cesium. Cesium is a fission product of nuclear fission of uranium-235 or other isotopes in nuclear reactors. Cesium-137 emits neutron and has a half-life of about 30 years. Polonium is an alpha emitter having a half-life of 138.4 days and decays to the stable isotope, Pb. Polonium has an alpha form having a simple cubic crystal structure in a single atom basis and a beta form that is rhombohedral. Polonium, such as polonium-210 in the presence of beryllium emits neutrons. A mixture of polonium with beryllium (Po—Be) emits neutrons. Alternatively, Californium is radioactive chemical element with symbol Cf and atomic number 98. Isotopes of californium emit neutrons and californium is used to aid in the start-up of nuclear reactors, and for neutron diffraction and neutron spectroscopy. The summary of the invention is provided as a general introduction to some of the embodiments of the invention, and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein. Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications and improvements are within the scope of the present invention. As shown in FIG. 1, an exemplary neutron beam diffraction material treatment system 100 comprises a first neutron beam source 20 and a second neutron beam source 20′ that create neutron beams 22, 22′ that are intersecting on a work-piece 80. The intersecting neutrons beams create neutron diffraction that produces a treatment portion within the work-piece, such as on the surface of the work-piece or within the depth of the work-piece. Also shown in FIG. 1 is a neutron beam regulator system 12, as described herein, that is coupled with the first neutron beam source. The neutron beam source may be used to contain the neutron or modulate the intensity of the neutron beam, as described herein. In this exemplary embodiment, the power control system 12 comprises a power control system 13, a power control system housing 40, at least one neutron beam source power supply output 34, a magnetic coil power supply output and a modulating coil output 37. It is to be understood that a single neutron beam regulator system may be coupled with both the first and second neutron beam sources or a separate neutron beam regulator system may be couple with each neutron beam source. In an alternative embodiment, magnetic coil extends around both the first and second neutron beams and may be controlled by a single regulator. It is also to be understood that two or more neutron beam sources and/or beams may be utilized in the neutron beam diffraction material treatment system, as described herein. The magnetic coils 15 shown in FIG. 1 are discrete magnetic coils and have a separate power supply, via separate magnetic coil plugs 38, to the power control system. The work-piece 80 is configured on a work-piece station 81 that may be configured to move in one or more direction and/or rotate. As shown in FIG. 2, an exemplary work-piece 80 is being treated with the neutron beam diffraction material treatment system, as described herein. A first neutron beam 26 and a second neutron beam 27 are intersecting on the work-piece at an intersecting point 112 which creates neutron diffraction 122. The intersection of the two neutron beams and the neutron diffraction treats the work-piece material to produce a treated work-piece portion 114. A treated work-piece portion may be subjected to an elevated temperature and/or the entrapment of neutrons from the intersection of the two neutron beams. The treated work-piece portion in this embodiment is on the surface of the work-piece. As shown in FIG. 3, an exemplary work-piece 80 is being treated with the neutron beam diffraction material treatment system, as described herein. The first and second neutron beams 26, 27, respectively, are intersecting within the depth of the work-piece, or below a work-piece surface 110. The depth 111 of the intersecting point 112 from the work-piece surface 111 may be any suitable depth and may be dynamically changed to produce various shapes and geometries of treated work-piece portions. As shown in FIG. 3 a cube shaped treated work-piece portion 114 has been created below the work-piece surface. The treated work-piece portion 114 is indicated by the cross-hashed cube within work-piece and is a bulk treated work-piece portion, as it does extend to a work-piece surface 110. In addition, the treated work-piece portion is a discrete work-piece portion having a defined outer surface that is not connected with another treated work-piece portion. As shown in FIG. 4, an exemplary work-piece 80 is being treated with the neutron beam diffraction material treatment system, as described herein. A cylindrical shaped treated work-piece portion is being created by the movement of the intersecting point 112, as indicated by the bold arrow. A large portion of the work-piece is a non-treated work-piece portion 116. Both of the neutron beams are actuated in coordinated actuation, such that the intersecting point moves along the cylindrical shape to produce the cylindrically shaped treated work-piece portion. The neutron beams may be actuated in any suitable manner, such as along one or more axes, or rotated about any axis, such as a traditional X. Y, and Z axis configuration as shown. This cylindrical treated work-piece portion may be configured to reinforce a coupling or fastener that in attached or inserted into the work-piece 80. For example, a pin or a bolt may be configured for insertion into a cylindrically shaped treated work-piece portion. Treatment of the work-piece, as shown may reduce any wear associated with forces exerted on the pin or fastener, or may strengthen the attachment of the pin or fastener. As shown in FIG. 5 an exemplary work-piece 80 is being treated with the neutron beam diffraction material treatment system, as described herein. Two elongated square shaped treated work-piece portions 114 have been produced, as indicated by the cross-hashed areas. Linear or elongated treated work-piece portions may strengthen the work-piece primarily in one direction, whereby the work-piece has a higher stiffness or break strength in the axis of the elongated treated work-piece portions, for example. As shown in FIG. 6, an exemplary work-piece 80 has been treated with the neutron beam diffraction material treatment system, as described herein, to produce an exemplary I-beam shaped treated work-piece portion 114. The I-beam shaped portion has two planar portions that are parallel and in this example extend along the outer surface 110 of work-piece and a connecting portion that extends through the bulk or depth of the work-piece between the two planar portions. An I-beam shape is well known for providing a stiff structural member with reduced weight. As shown in FIG. 7 the I-beam shaped treated work-piece portion extends through the work-piece from Face A to Face B. As shown in FIG. 8, an exemplary work-piece 80 has been treated with the neutron beam diffraction material treatment system, as described herein, to produce a plurality of planar shaped treated work-piece portions 114 with non-treated work-piece portion 116, therebetween. The planar shaped treated work-piece portions are substantially parallel and extend from a first surface 110 to a second surface 110′ of the work-piece material. As shown in FIG. 9, the planar shaped treated work-piece portion extends through the work-piece from Face A to Face B. The planar shaped treated work-piece portions form treated panel portions within the interior of the work-piece. As shown in FIG. 10, an exemplary work-piece 80 has been treated with the neutron beam diffraction material treatment system, as described herein, to produce a cylindrical shaped treated work-piece portion 114 around as aperture 115. As shown in FIG. 11, the cylindrical shaped treated work-piece portion extends through the work-piece from Face A to Face B. As shown in FIG. 12, the cylindrical shaped treated work-piece portion extends around the aperture 115. As shown in FIG. 13 an exemplary work-piece has a thread type treated work-piece portions 132. FIG. 14 shows a cross-sectional view along line 14-14 of FIG. 13 showing that the thread type treated work-piece portions extend through the work-piece and are configured within the interior volume of the work-piece 80. FIG. 15 shows a cross-sectional view along line 15-15 of FIG. 13 showing that the thread type treated work-piece portions 132 extend through the work-piece from surface 110 to surface 110′. A thread type treated work-piece portion is elongated having a length 134 that is more than about 10 times a maximum cross-length dimension 135, as shown in FIG. 15. It is to be noted that the diameter or cross-section of a thread type treated work-piece portion may change over the length, wherein in a first location along the length the cross-dimension of the treated portion is greater than in a second location along the length. FIG. 16 shows a perspective view of an exemplary neutron beam diffraction material treatment system 100 comprising a first neutron beam source 20 and a second neutron beam source 20′ that are producing neutron beams 22, 22′ respectively. The neutron beams are intersecting at intersection point 112 on a work-piece 80. Neutron beam source 20 and 20′ are configured to rotate about two axes as indicated by the bold arrow around the axes lines. These two degrees of freedom enables the intersection point 112 to be moved from one location to another location. An intersecting point may be dynamically moved from a first position to a second position, wherein the work-piece is treated in between the first and second locations. FIG. 17 shows a perspective view of a first neutron beam 26 and a second neutron beam 27 intersecting on a work-piece 80 to create neutron diffraction 122 and having an offset angle 120. The second neutron beam is offset from the first neutron beam by offset angle 120 which may be any suitable offset angle including more than about 5 degrees to 180 degrees. The X, Y. and Z axes are shown and it is to be understood that the neutron beam may be directed in any orientation along or between these axes. FIG. 18 shows a perspective view of a neutron beam 26 and a second neutron beam 27 intersecting on a work-piece 80 to create neutron diffraction 122 and having an offset angle 120. In this embodiment, the second neutron beam is at a much lower offset angle than the embodiment shown in FIG. 17. As shown in FIG. 19, an exemplary neutron beam regulator system 12 comprises a power control system 13 and a plurality of discrete magnetic coils 16-16″ configured around a neutron beam 22 and extending substantially from the neutron beam source 20 to the target 19, or the neutron beam length 60. Each of the discrete magnetic coils has an individual power supply 35 and individual or discrete magnetic coil plugs 39. This magnetic coil configuration may be configured to both contain the neutron beam and also to modulate the neutron beam through changes in the magnetic field strength or direction. One or more of the discrete magnetic coils may be a modulating magnetic coil 17 and be coupled with a modulating coil output 37. A modulating magnetic coil controller 48 may be configured to enable a user to modulate the level and/or direction of the magnetic field 11 produced by one or more modulating magnetic coils 17. The electrical current running through the coils will produce a magnetic field as indicated by the spiral having an arrow around the coil 11′ and will follow the principle of the “right hand rule”. The modulating magnetic coil controller 48 is depicted as a dial but may be any suitable user input device including, but not limited to, a button, knob, computer input screen or field and the like. The power control system 13 is configured in a single power control housing 40 having a single plug for coupling with a power source 30, a neutron beam source power supply output 34 and one or more magnetic coil power supply outputs 35. The containment magnetic coils 15 may produce a magnetic field that that excludes neutrons from outside of the coils from entering and may steer or direct the outside neutrons away from the neutron beam regulator system 12. As shown in FIG. 20, an exemplary neutron beam regulator system 12 comprises a continuous magnetic coil 52 configured around a neutron beam and extending substantially the entire neutron beam length 60. The continuous magnetic coil is a spiraled coil 54 having a continuous length from a first end to a second end, or extending spiraling substantially the entire length of the neutron beam length 60. The continuous magnetic coil may be a containment magnetic coil 15 and may also be configured as a modulating magnetic coil 17. A user may run the neutron beam regulator system with a constant magnetic field intensity whereby the magnetic coil acts simply as a containment magnetic coil. In another embodiment, a user may vary the magnetic field intensity, thereby causing the magnetic coil to be a modulating magnetic coil 17. A neutron beam 22 exits the neutron source 20 at the neutron beam output 24 and extends to a target 19. The target is configured on a work-station 81 having an actuator 88 to move the target up into the magnetic field generated by the magnetic coil 15. The actuator may enable a user to load a work-station with a work-piece for processing and then actuate the part up into the magnetic coil. After the work-piece has been processed, the actuator may move the work-station down and from the magnetic coil to allow a user to remove the work-piece or target. This actuating work-station further reduces neutron radiation exposure by placing the work-piece within the magnetic field. The direction of the electrical current around the coils, as indicated by the arrows tangent with the magnetic coils, produces a magnetic field 11 that contains the neutron beam 22 and also directs it from the beam outlet 24 to the target 19. As shown in FIG. 21, an exemplary neutron beam regulator system 12 comprises a continuous magnetic coil 52 configured partially around the neutron beam source 20 or generator. The magnetic coil 15 extends upstream of the neutron beam output, or the location where the beam exits the neutron beam generator. Again, this configuration reduces neutron radiation exposure by placing the neutron beam output 24 within the magnetic field. As shown in FIG. 22, an exemplary neutron beam regulator system 12 comprises a continuous magnetic coil 52 configured partially around the neutron beam source 20 and partially around a work-piece station 81. The magnetic coil extends downstream of where the neutron beam hits the target or work-piece station. This configuration reduces neutron radiation exposure by placing both the neutron beam output 24 and the target within the magnetic field. It is to be understood that additional neutron absorbing material may be configured around the neutron source, the target or work-station, or along the neutron beam length. A magnetic coil may be configured in a housing that comprises neutron absorbing materials such as boron, for example. As shown in FIG. 23, an exemplary power control system 13 comprises a power safety feature 43 comprising a magnetic coil power sensor 42 and a switch 44 that are configured to terminate power to a neutron beam source 20 in the event that no power, or a power level below some threshold power level, is being drawn by a containment magnetic coil 15. The switch 44 is in an open position and the neutron beam source is deactivated. As shown, the magnetic coil plug 38 is not plugged into the magnetic coil power supply output 35, and therefore no power is being drawn by the magnetic coil 15. A power safety feature may be configured with a magnetic coil power sensor that is coupled with one or more magnetic coil power supply outputs and specifically magnetic coils configured as containment magnetic coils. The neutron beam plug 39 is plugged into the neutron beam power supply output 34 but no power is provided. This safety feature ensures that the neutron beam will not be activated unless a containment magnetic coil is drawing power. A controller 46, such as a microprocessor may be configured to control the functions of the power control system. As shown in FIG. 24, an exemplary power control system 13 comprises a power safety feature 43 that has enabled power supply to the neutron beam power supply output 34. The switch 44 is in a closed position and the neutron beam source 20 is activated, as the magnetic coil 15 is drawing power to contain the neutron beam 22. As shown in FIG. 25, an exemplary neutron beam regulator system 12 comprises a containment magnetic coil 15 configured around a modulating magnetic coil 17. The containment magnetic coil is configured to reduce neutron radiation leakage from the system and the modulating magnetic coil is configured to change one or more properties of the neutron beam including, but not limited to, shape, intensity, velocity, direction and polarization. The modulating magnetic coil is inside of the containment magnetic coil in this embodiment. Any suitable combination of containment and modulating magnetic coils may be configured with a neutron beam regulator, as described herein. A containment magnetic coil may be a spiral coil that extends substantially the entire length of the neutron beam, and a modulating magnetic coil may be a discrete coil that is configured more proximal to the target. In another embodiment a modulating coil is a spiral coil that is configured proximal to the target but does not extend to the neutron beam generator. The neutron beam 22 is incident on a work-piece 80 that is configured on a work-piece station 81. A work-piece actuator 87 is configured to move the work-piece in one or more directions to change where the neutron beam hits the work-piece. As shown in FIG. 25, the work-piece actuator is configured to move the work-piece both back and forth, as indicated by the double-ended arrow, and also rotate the work-piece. These two actuation controls will enable the entire work-piece to be treated with the neutron beam. The incident location 89 of the neutron beam on the work-piece may be changed by actuation of the work-piece actuator to allow partial or complete surface treatment of the work-piece. A beam location program 98 is configured with the neutron beam regulator system 12 and enables positive tracking of a neutron beam on a work-piece as the work-piece is moved. A treatment program 99 is configured with the neutron beam regulator system 12 and enables modulation of the neutron beam as a function of position on the work-piece. A treatment program enables a work-piece to be treated with different levels of the neutron beam depending on the position on the work-piece. As shown in FIG. 26, an exemplary work-piece 80 has areas treated with different levels of neutron bombardment through magnetic coil modulation as indicated by the different shaded areas of the work-piece. This work-piece has two apertures 86, 86′, or bolt holes. This particular work-piece needs to be stiff in the areas 82, 84, around these fastening locations as indicated by the dark shaded areas. The work-piece however needs to be more supple, or less stiff, in the portion between the two apertures 83, as indicated by the lighter shading. The neutron beam regulator system, as described herein, enables this precise and controlled stiffening of a work-piece through modulated neutron bombardment. The neutron beam shape, intensity, velocity, direction and polarization may be modulated by a modulated magnetic coil as incident neutron beam location is changes over the work-piece. As shown in FIG. 27, an exemplary neutron beam system 28 comprises an excluding magnetic coil 18 that is a continuous magnetic coil 52 configured around the neutron beam and extending substantially the entire neutron beam length 60. The continuous magnetic coil is a spiraled coil 54 having a continuous length from a first end to a second end, or extending spiraling substantially the entire length of the neutron beam length 60. The continuous magnetic coil is an excluding magnetic coil 18 and produces an excluding magnetic field 66 as indicated by the bold arrows. The excluding magnetic field substantially prevents outside neutrons 64 from entering into the coil area, interfering with the neutron beam or impacting the target 19. An excluding magnetic coil may be used in situations where the target is sensitive to neutron and any exposure to stray neutrons may interfere with the target or reflection/diffraction measured from said target. It is to be understood that an excluding magnetic coil may be added to any of the neutron beam regulator systems as defined herein. It is also to be understood that an excluding magnetic coil may be configured as a continuous or discrete coil and may extend at least partially around the target or neutron source output. As shown in FIG. 28, a first beam 230 and second beam 240 have coherence 250 at a treatment location 201. A first beam generator 220 and second beam generator are offset from each other by an offset distance 235. Note that the first beam has a much lower frequency than the second beam. The first beam and second beam are coherent at the treatment location, the first and or second beam may be changed in frequency or amplitude to adjust a position of coherence and to treat a desired treatment location. In addition, the first and/or second beam generator may be adjusted in position, displaced in one more directions, to change the location of coherence. As shown in FIG. 29, a first beam 230 has a first frequency and a second beam 240 has a second frequency that is higher than the first beam frequency. The first and second beams are coherent at a plurality of coherent locations 250, 250. The frequency of the second beam is substantially different from the frequency of the first beam, wherein the second beam has a frequency that is at least 20% greater the first beam. As shown in FIG. 30, a first beam 230 has a first frequency and second amplitude and a second beam 240 has a second frequency and second amplitude that is higher than the first beam amplitude. The first and second beams are coherent at a plurality of coherent locations 250, 250. The first beam has an amplitude that is substantially less than the second beam, wherein the second beam has an amplitude that is at least 20% more that the first amplitude. As shown in FIG. 31, a first beam 230 and second beam 240 have a coherence 250 over a number of periods. As shown in FIG. 32, a first complex beam 231 has a frequency that changes as a function of time. The first beam also has a change in amplitude as a function of time. The first beam is defined by a complex wave equation, such as by Fourier Transform. As described herein, a control system may regulate a first and/or second beam to be defined by a complex wave equation. The complex beams or waves are defined by a complex wave equation, as defined herein and described in detail in the reference incorporated by reference herein. The beam 231 has a first time domain, or period of time, having a much higher frequency and amplitude that a second time domain, or second period of time. The beam may oscillate between these two domains as a function of time in predictable or controlled manner, as defined by a complex wave equation. A control system may utilize a computer program to modulate or change a wave frequency and/or amplitude or change a domain. As shown in FIG. 33, an exemplary coherent beam treatment system 200 incorporates a control system 210 that has a first beam generator 220 and second beam generator 220 that produce a first beam 230 and second beam 240, respectively. A beam regulator 260 regulates the first beam 230 to be coherent 250 at a treatment location 201. It is to be understood that the first and second beam generators may be enclosed in a single housing or enclosure 207. One or more microprocessors 270 may incorporate at control program that provides instructions to the beam regulator(s). The control program may generate a beam defined by a complex wave, or a beam that changes frequency and/or amplitude as a function of time. A complex wave equation may utilize Fourier Transform. As shown in FIG. 34, an exemplary coherent beam treatment system 200 incorporates a control system 210 that has a first beam generator 220 and second beam generator 220′ that are offset by an offset distance 235c from each other and produce beams that intersect at a treatment location 201. The microprocessor 270 provides instructions to the beam regulators 260 to have the beams be coherent beams 250 at the treatment location 201. As shown in FIG. 35, an exemplary coherent beam treatment system 200 incorporates a control system 210 comprising a microprocessor 270 that interfaces with the beam regulator to create beam coherence 250 at a treatment location 201. The microprocessor may utilize a computer program that establishes a complex wave equation, such as a Fourier transform equation and the like to produce a high energy beam that is a complex wave. The computer program may also provide equations for simple waves, having constant amplitude and frequency for one or more of the beams. As describe herein, the beams may have different amplitude and/or frequency however, or one may move with respect to the other or the treatment location. In this exemplary embodiment, a beam generator 260 produces an input beam 237 that is incident on a beam splitter 280, such as a prism 281. The beam splitter splits the input beam into a first split beam 231 and a second split beam 241. The second split beam 241 is incident on a mirror 290 that reflects and directs the second split beam to the treatment location. The first split beam and second split beam intersect with and are coherent with each other at the treatment location 201. The mirror may be moved by the control system to direct the second split beam. A user interface 214 is shown that may be used to provide inputs to the control system. A material input factor may be input into the system and this input may be used to control the first and or second beams, or split beams for transmission through the material 209. As shown in FIG. 36, an exemplary coherent beam treatment system 200 incorporates a control system 210, a beam splitter 280 and a mirror 290. The second split beam is reflected by the mirror and then is received by a beam regulator. The second split beam may be regulated to produce coherence with the first split beam 231 at the treatment location 201. It is to be understood that the second split beam 241 may be received by a beam regulator before being incident on a mirror 290. As shown in FIG. 37, a proton beam has a periodic high depth of penetration 295. A control system may regulate a proton beam such that the high depth of penetration is coherent with another beam at a treatment location. As shown in FIG. 38, an exemplary spacecraft 326 is moving through outer space 320 and is propelled by an exemplary neutron propulsion device 300 comprising a neutron beam generator 220 and neutron beam source 20 as well as a magnetic coil 15 configured around the emitted neutron beam 22. The neutron beam is emitted from the spacecraft to produce thrust 350 and propel the spacecraft in a propulsion direction 355, as indicated by the bold arrows. The magnetic coils in this embodiment are self-contained magnets 51 requiring no supply of power to produce the magnetic field. As described herein a self-contained magnet may be natural magnets or neobdium magnets. The neutron beam shown in this embodiment is powered by a neutron beam power source 30. The magnetic coils may extend around the emitted neutron beam 22 from the beam outlet 24 from the generator to where the beam exits the spacecraft, or substantially along the length of the emitted beam within the spacecraft such as at least 80% of the length from the beam outlet 24 to exiting the spacecraft or at least 90% of the length. As shown in FIG. 39, an exemplary self-contained spacecraft 321 is moving through space 320 and is propelled by an exemplary self-contained neutron propulsion device 301 comprising a neutron beam generator 220 and natural or self-contained neutron beam source 21 as well as a self-contained magnets 51 configured as magnetic coils 15 around the emitted neutron beam 22. The neutron beam is emitted from the spacecraft to produce thrust 350 and propel the spacecraft in a propulsion direction 355, as indicated by the bold arrows. The magnetic coils in this embodiment are self-contained magnets requiring no supply of power to produce the magnetic field. As described herein, a self-contained magnet may be natural magnets or neobdium magnets. The neutron beam shown in this embodiment is self-contained neutron beam source such as a radioactive material, Californium-252, Cesium-137 and polonium-beryllium (Po—Be). As shown in FIGS. 40 and 41, an exemplary spacecraft 326 has a pair of neutron beam propulsion devices 300, 300′ configured to propel and steer the spacecraft. The neutron propulsion devices comprise a direction device 390, configured to change the direction of the emitted neutron beam 22, and thereby steer the spacecraft. The neutron beam propulsion devices may be self-contained neutron beam propulsion devices as described herein. As shown in FIG. 42, an exemplary spacecraft 326 has an exemplary neutron beam propulsion device 300. This spacecraft may orbit a planet, such as Earth and be a satellite 324, or may be propelled to travel through interspace or be an interplanetary spacecraft 328, such as a data gathering spacecraft for taking images and collecting data related to outer space and planets. The neutron beam propulsion device has a plurality of magnetic coils 15, configured around the neutron emitted neutron beam 22. The neutron beam source may be a self-contained neutron beam source 21 and the magnets may be self-contained magnets, as described herein, thereby producing a self-contained propulsion spacecraft 321. As shown in FIG. 43, an exemplary neutron beam regulator system 12 comprises a power control system 13 and a plurality of discrete magnetic coils 16-16″ configured around a neutron beam 22 and extending substantially from the neutron beam source 20 to the target 19, or the neutron beam length 60. Each of the discrete magnetic coils has an individual power supply 35 and individual or discrete magnetic coil plugs 39. This magnetic coil configuration may be configured to both contain the neutron beam and also to modulate the neutron beam through changes in the magnetic field strength or direction. One or more of the discrete magnetic coils may be a modulating magnetic coil 17 and be coupled with a modulating coil output 37. A modulating magnetic coil controller 48 may be configured to enable a user to modulate the level and/or direction of the magnetic field 11 produced by one or more modulating magnetic coils 17. The electrical current running through the coils will produce a magnetic field as indicated by the spiral having an arrow around the coil 11′ and will follow the principle of the “right hand rule”. The modulating magnetic coil controller 48 is depicted as a dial but may be any suitable user input device including, but not limited to, a button, knob, computer input screen or field and the like. The power control system 13 is configured in a single power control housing 40 having a single plug for coupling with a power source 30, a neutron beam source power supply output 34 and one or more magnetic coil power supply outputs 35. The containment magnetic coils 15 may produce a magnetic field that that excludes neutrons from outside of the coils from entering and may steer or direct the outside neutrons away from the neutron beam regulator system 12. In addition, a beam reflector/splitter 420 is configured in the path of the neutron beam 22 to create a reflected neutron beam 422 that is directed back toward the source to create diffraction with the source neutron beam. The angle of refraction of the reflected neutron beam to the source beam may be varied by the reflector/spiller to change the amount of diffraction of the source neutron beam. As shown in FIG. 44, an exemplary coherent beam treatment system 200 incorporates a control system 210, a beam splitter 280 and a mirror 290. The second split beam 241 is reflected by the mirror 290 and then is received by a beam regulator 260′. The second split beam 241 may be regulated to produce coherence with the first split beam 231 at the treatment location 201. A beam regulator 260″ may regulate the first split beam 231 and may change the intensity or frequency of the first split beam to produce coherence. The first or second split beams may be regulated by their corresponding regulators to produce coherence 250 or diffraction as required at the treatment location 201. It is to be understood that the second split beam 241 may be received by a beam regulator before being incident on a mirror 290. As shown in FIG. 44, the neutron beam regulator system comprising a magnetic coil that is configured to extend around the second neutron beam between the first neutron beam source and the work-piece, or more precisely between the beam splitter and the workpiece. Also, the neutron beam regulator system comprises a magnetic coil 15 that is configured to extend around the first neutron beam 231 between the first neutron beam source 220 and the work-piece 19 or treatment location 201. Coherence 250 occurs at the treatment location. This exemplary system has two independent beam regulator systems, whereby the first and/or second neutron beam can be controlled in neutron beam shape, intensity, velocity, frequency, amplitude, direction and polarization. Definition The term space as used herein to describe the location of travel of a spacecraft is outside of the Earth's atmosphere, or outer space. The term, coordinated actuation, as used herein, means that a first and second neutron beam are moved to create an intersecting point that moves along or within a work-piece. A target is any object that a neutron may be incident on for treatment, analysis or conditioning, including neutron bombardment to stiffen or harden a material or work-piece. A target may be a person's tissue and particularly a tumor. A target may be a physical work-piece that is being analyzed or conditioned through neutron bombardment and may be a metal, plastic, ceramic, composite and the like. It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the spirit or scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents. Fourier transform mathematical expressions, equations, and applications, including forms of differential equations and the use of Fourier transforms to create coherence are described in the following references, all of which are incorporated by reference herein: Lectures Notes For, EE261: The Fourier Transform and its Application, Prof. Brad Osgood, Electrical Engineering Department, Stanford University (This document is provided with the filing of this application); The Fourier Transform and its Application, Third Edition, Ronald N Bracewell ISBN-13: 978-0073039381, McGraw-Hill Science/Engineering/Math; Jun. 8, 1999; Fourier Transforms; Ian N. Sneddon, ISBN-13: 080-0759685226, Dover Publications, Sep. 28, 2010; Fourier transform representation of an ideal lens in coherent optical systems, (NASA technical report, NASA TR R-319), B0006CN02W, National Aeronautics and Space Administration; for sale by the Clearinghouse for Federal Scientific and Technical Information, Springfield, Va. (1970); sds Fourier Transforms and Imaging with Coherent Optical Systems, Okan K. Ersoy, John Wiley & Sons, Inc, 2007; and Linear Systems, Fourier Transforms, and Optics, Jack D. Gaskill, ISBN-13: 978-0471292883, Wiley-Interscience; 1 edition (June 1978).
	abstract	An Actinium-225 generator is provided. The generator includes a neutron source; a neutron target arranged to receive neutrons emitted from the neutron source, wherein the neutron target comprises nickel; and a proton target arranged to receive protons emitted from the neutron target, wherein the proton target comprises radium-226. Methods for producing Actinium-225 are also provided.
048225550	abstract	A container for L-shaped plate-like objects, comprising an elongated spring provided in the container so as to extend thereacross, one end of the elongated spring being fixed to one inner surface of the container with the other end being free and able to urge the L-shaped plate-like object to an inner surface of the container which is opposite to the inner surface to which the plate spring is fixed.
	summary
	abstract	A method for prognostics of a structure subject to loads, particularly an aircraft structure, includes, detecting the state (strains) of the structure at multiple primary points and additional points. The loads acting on the structure associated with the state detected in the primary points are determined. Based on the determined loads, the state of the structure in the additional points is estimated. The estimated state of the structure is compared with the state detected in the additional points. A soundness state of the structure is assessed if the estimated and detected values of the state quantity are in agreement, or a defectiveness state of the structure if such values differ.
052346099	abstract	Disclosed is an X-ray-permeable membrane for X-ray lithographic mask for fine patterning in the manufacture of semiconductor devices having good transparency to visible light and exhibiting excellent resistance against high-energy beam irradiation. The membrane has a chemical composition expressed by the formula SiC.sub.x N.sub.y and can be prepared by the thermal CVD method in an atmosphere of a gaseous mixture consisting of gases comprising, as a group, the elements of silicon, carbon and nitrogen such as a ternary combination of silane, propane and ammonia.
059563818	claims	1. A configuration for detecting the dropping of at least one control element into a reactor core, comprising: detectors disposed along a fall path of at least one control element of a reactor core defining a fall time, said detectors having signal outputs; delay components having a delay time proportional to the fall time, said delay components each connected to the signal output of a respective one of said detectors; a common adder component connected to said delay components, said common adder component having an output side; and a monitoring device connected to the output side of said common adder component. 2. The configuration according to claim 1, including differentiator components each connected between a respective one of said detectors and said adder component. 3. The configuration according to claim 1, including thresholding components each connected between a respective one of said detectors and said adder component. 4. The configuration according to claim 1, wherein at least said delay components are formed in at least one programmed computer. 5. The configuration according to claim 1, wherein said monitoring device is formed of at least one programmed computer. 6. The configuration according to claim 1, wherein at least said delay components, said common adder component and said monitoring device are formed of at least one programmed computer. 7. The configuration according to claim 1, wherein at least said common adder component is formed in at least one programmed computer.
053234324	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for assembling a nuclear fuel assembly for nuclear reactors, and in particular to a simple apparatus for loading fuel rods into the fuel assembly efficiently. 2. Background Art A conventional fuel assembly such as the one disclosed in a U.S. Pat. No. 5,068,081, shown in FIG. 2, is known. In this figure, the numerals 1 and 2 refer to top and bottom nozzles, respectively, which are disposed vertically and oppositely spaced apart, and having a plurality of rigidly fixed control-rod guide pipes 3 (hereinbelow referred to as guide pipes 3) between the top nozzle 1 and the bottom nozzle 2. In the mid section of the guide pipes 3 are a plurality of grids 4 disposed vertically and spaced apart from each other. The grids 4 are, as shown in FIGS. 3 to 5, constructed of a plurality of straps 7 made of thin metal strips having slits 8 formed in the longitudinal direction thereof, and by interlocking the slits 8 to form lattices. The structure formed by the lattices is known as the grid cells 5, and a dimple 9 and spring 10 are formed on each of the opposing walls of the grid cells 5. A fuel rod 6 inserted into a grid cell 5 is pressed against the dimple 9 by the spring 10, thereby holding the fuel rod 6 firmly in the grid cell 5 therebetween. A method of inserting a fuel rod 6 in a grid cell 5 is known, for example, in Japanese Patent Application, Laid-open publication (Kokai) H2-181,699 which involves the use of a key device to deactivate the spring 10, and gripping the tip of a fuel rod 6 by means of a pull-in device, which then enables the fuel rod 6 to be pulled into the grid cell 5. However, such methods presented problems because of the necessity of pull-in device and other ancillary control devices, and the complexities of the devices mean that the operations become cumbersome and lengthy. SUMMARY OF THE PRESENT INVENTION The present invention was made to resolve the above mentioned problems associated with the conventional assembling apparatus, by providing an apparatus of a simple mechanical construction, enabling the insertion of fuel rods into the grids efficiently and without causing surface damages on the fuel rods. An apparatus for assembling a fuel assembly containing longitudinally extending fuel rods comprises: (a) a longitudinally extending fuel rod magazine containing a plurality of fuel rods; PA1 (b) a plurality of fluid-pressure operated loading cylinders provided on the fuel rod magazine, for pushing specific fuel rods of the plurality of fuel rods in a longitudinal direction into the grid cells, wherein each of the loading cylinders are disposed coaxially with corresponding ones of the plurality of fuel rods contained in the fuel rod magazine; PA1 (c) a plurality of grid support frames spaced apart and disposed in the longitudinal direction of the assembly so as to vertically support the plurality of fuel rods being loaded into the grid cells of the grids. According to the present invention, it becomes possible to insert the fuel rods into the grids by first placing the grids in the grid support frames, and simply by operating the fluid-driven loading cylinders provided on the invented assembling apparatus, it becomes possible to push the specified fuel rods out of the fuel rod magazine towards the grids, and inserting the fuel rods into the corresponding grid cells. Therefore, the assembly operation involves only the operation of the pressure-driven loading cylinders in association with a fuel rod magazine which hold the plurality of fuel rods. Therefore, the construction of the assembling apparatus is simplified significantly in comparison to the conventional apparatus such as the pull-in rods system. The operational procedure is correspondingly simplified because the necessity of complex operations such as gripping of the fuel rods has been eliminated.
055442102	abstract	A pressure vessel apparatus for containing fluid under high pressure and temperature including pressure surges caused by in-vessel explosions includes a vessel main body, a vessel top body and a vessel head. Elongated tendons interconnect the vessel main body to the vessel top body and elongated tendons with removable anchors also connect the vessel head to the vessel top body. The tendons with insulated protecting sleeves connecting the vessel main body to the vessel top body are chosen to allow the vessel top body to temporarily separate from the vessel main body before the vessel head separates from the vessel top body. These tendons may be mounted directly, on springs, or on dampers in order to provide optimum (minimum) response to the postulated load cases. Reinforced and internally supported bellows are provided about a joint between the vessel main body and the vessel top body to prevent leakage from the interior of the pressure vessel apparatus upon liftoff of the vessel top body from the vessel main body. Continuously wound prestressed wire strands or bands are provided around the periphery of the vessel walls.
	summary
056169272	claims	1. A frame-supported pellicle which is an integral body comprising: (a) a frame made from a rigid material having substantially parallel end surfaces; (b) a transparent film of a synthetic resin spread over and adhesively bonded to one end surface of the frame in a slack-free fashion; and (c) a layer of a pressure-sensitive adhesive on the other end surface of the frame, the adhesive bonding strength of the pressure-sensitive adhesive being reducible by heating or by irradiating with light. 2. The frame-supported pellicle as claimed in claim 1 in which the adhesive bonding strength of the pressure-sensitive adhesive is reducible by heating at a temperature in the range from 70.degree. C. to 150.degree. C. 3. The frame-supported pellicle as claimed in claim 1 in which the adhesive bonding strength of the pressure-sensitive adhesive is reducible by the irradiation with ultraviolet light in an irradiation dose of 200 mJ/cm.sup.2 or larger.
060382791	claims	1. An X-ray generating device for use with an X-ray projection optical system having X-ray mirrors for projecting an image of an irradiated first object to a second object, said device comprising: a laser source for generating a laser beam; a target having a plurality of points for receiving the laser beam, the plurality of points forming a plurality of high temperature plasma portions, each of which generates an X-ray beam; and an illuminating optical system for irradiating an object with the X-ray beams from the high temperature plasma portions substantially under Kohler's illumination condition. a laser source for generating a laser beam; an aperture, having a variable shape, for receiving the laser beam and for defining a shape of a secondary light source; a target for receiving the laser beam and for generating X-rays from portions of high temperature plasma on the target; and an illuminating optical system for irradiating an object with the X-ray beams from the high temperature plasma portions substantially under Kohler's illumination condition. (i) an X-ray generating device comprising: (ii) irradiating means for irradiating a first object with the plurality of X-ray beams generated by said X-ray generating device; and (iii) an X-ray projection optical system having X-ray mirrors for projecting an image of the irradiated first object to a second object. (i) an X-ray generating device comprising: (ii) irradiating means for irradiating an object with the X-rays generated by said X-ray generating device; and (iii) an X-ray projection optical system having X-ray mirrors for projecting an image of the irradiated first object to a second object. generating at least one laser beam from at least one laser source; providing a target having a plurality of points for receiving the at least one laser beam; forming, from the plurality of points, a plurality of high temperature plasma portions; generating X-ray beams from each of the high temperature plasma portions; and irradiating an object with the X-ray beams from the high temperature plasma portions substantially under Kohler's illumination condition. generating a laser beam from a laser source; providing an aperture, having a variable shape, for receiving the laser beam and for defining a shape of a secondary light source; providing a target for receiving the laser beam; generating X-rays from portions of high temperature plasma on the target; and irradiating an object with the X-ray beams from the high temperature plasma portions substantially under Kohler's illumination condition. generating at least one laser beam from at least one laser source; providing a target having a plurality of points of high temperature plasma for receiving the at least one laser beam; forming, from the plurality of points, a plurality of high temperature plasma portions; generating X-ray beams from each of the high temperature plasma portions; irradiating a mask with the X-rays generated from the high temperature plasma portions; and projecting an image of a pattern carried by the irradiated mask onto a semiconductor wafer to produce a semiconductor device. generating a laser beam from a laser source; providing an aperture, having a variable shape, for receiving the laser beam and for defining a shape of a secondary light source; providing a target for receiving the laser beam; generating X-rays from portions of high temperature plasma on the target; irradiating a mask with the X-rays generated from the high temperature plasma portions; and projecting an image of a pattern carried by the irradiated mask onto a semiconductor wafer to produce a semiconductor device. laser source means for generating at least one laser beam; a target having a plurality of points for receiving the at least one laser beam, the plurality of points forming a plurality of high temperature plasma portions simultaneously, each of which generates an X-ray beam; and an X-ray projection optical system having X-ray mirrors for projecting an image of an irradiated first object to a second object by the X-ray beams generated by the plurality of high temperature plasma portions, wherein the X-ray beams from the plurality of high temperature plasma portions are irradiated on the first object simultaneously. 2. An X-ray generating device according to claim 1, wherein the plurality of points are non-uniformly distributed. 3. An X-ray generating device according to claim 1, wherein the plurality of points are distributed in a distribution pattern such that the distribution density is lower in a central region than in a peripherals region. 4. An X-ray generating device for use with an X-ray projection optical system having X-ray mirrors for projecting an image of an irradiated first object to a second object, said device comprising: 5. An X-ray generating device according to claim 4, wherein said variable aperture controls at least one of the configuration, size, position and number of the portions of the laser plasma on the target. 6. An X-ray projection apparatus comprising: 7. An X-ray irradiating apparatus according to claim 6, wherein the plurality of points are non-uniformly distributed. 8. An X-ray irradiating apparatus according to claim 6, wherein the plurality of points are distributed in a distribution pattern such that the distribution density is lower in a central region than in a peripheral region. 9. An X-ray irradiating apparatus according to claim 6, wherein said irradiating means irradiates the object substantially under Kohler's illumination conditions. 10. An X-ray irradiating apparatus according to claim 6, further comprising optical means for projecting an image of a pattern carried by the irradiated mask onto a wafer. 11. An X-ray irradiating apparatus according to claim 10, wherein said optical means comprises a demagnifying image forming optical system. 12. An X-ray projection apparatus comprising: 13. An X-ray irradiating apparatus according to claim 12, wherein said variable aperture controls at least one of the configuration, size, position and number of the portions of the laser plasma on the target. 14. An X-ray irradiating apparatus according to claim 12, wherein said irradiating means irradiates the object substantially under Kohler's illumination conditions. 15. An X-ray irradiating apparatus according to claim 12, further comprising optical means for projecting an image of a pattern carried by the irradiated mask onto a wafer. 16. An X-ray irradiating apparatus according to claim 15, wherein said optical means comprises a demagnifying image forming optical system. 17. An X-ray generating method for use with an X-ray projection optical system having X-ray mirrors for projecting an image of an irradiated first object to a second object, said method comprising: 18. An X-ray generating method according to claim 17, wherein the plurality of points are non-uniformly distributed. 19. An X-ray generating method according to claim 17, wherein the plurality of points are distributed in a distribution pattern such that the distribution density is lower in central region than in a peripheral region. 20. An X-ray generating method according to claim 17, further comprising deflecting the at least one laser beam to the plurality of the points. 21. An X-ray generating method according to claim 17, further comprising effecting incoherent illumination of an object with the X-rays from the portions. 22. An X-ray generating method for use with an X-ray projection optical system having X-ray mirrors for projecting an image of an irradiated first object to a second object, said method comprising: 23. An X-ray generating method according to claim 22, further comprising applying the secondary laser beam to the target in a time series manner. 24. An X-ray generating method according to claim 22, further comprising controlling, using the variable aperture, at least one of the configuration, size, position and number of the portions of the laser plasma on the target. 25. An X-ray generating method according to claim 22, further comprising deflecting the at least one laser beam to the plurality of the points. 26. An X-ray generating method according to claim 22, further comprising varying the form of the portions by varying the shape of the variable aperture. 27. An X-ray generating method according to claim 26, further comprising effecting incoherent illumination of an object with X-rays from the portions. 28. A method of producing a semiconductor device, said method comprising the steps of: 29. A semiconductor device production method according to claim 28, wherein the plurality of points are non-uniformly distributed. 30. A semiconductor device production method according to claim 28, wherein the plurality of points are distributed in a distribution pattern such that the distribution density is lower in a central region than in a peripheral region. 31. A semiconductor device production method according to claim 28, further comprising deflecting the at least one laser beam to the plurality of points. 32. A semiconductor device production method according to claim 28, further comprising effecting incoherent illumination of the mask with the X-rays from the portions. 33. A semiconductor device production method according to claim 28, wherein said irradiating step comprises focusing the X-rays from the points onto the mask so as to effect Kohler's illumination of the mask. 34. A semiconductor device production method according to claim 28, wherein said irradiating step comprises causing the X-rays from the points to impinge on the mask at different angles. 35. A semiconductor device production method according to claim 34, further comprising changing the angular distribution of the X-rays, impinging on the mask. 36. A method of producing a semiconductor device, said method comprising the steps of: 37. A semiconductor device production method according to claim 36, further comprising applying the laser beam to the target in a time series manner. 38. A semiconductor device production method according to claim 36, further comprising controlling, using the variable aperture, at least one of the configuration, size, position and number of the portions of the laser plasma, on the target. 39. A semiconductor device production method according to claim 36, further comprising deflecting the at least one laser beam to the plurality of points. 40. A semiconductor device production method according to claim 36, further comprising varying the form of the portions by varying the shape of the variable aperture. 41. A semiconductor device production method according to claim 40, further comprising effecting incoherent illumination of the mask with X-rays from the portions. 42. A semiconductor device production method according to claim 36, wherein said irradiating step comprises focusing the X-rays from the points onto the mask so as to effect Kohler's illumination of the mask. 43. A semiconductor device production method according to claim 36, wherein said irradiating step comprises causing the X-rays from the points to impinge on the mask at different angles. 44. A semiconductor device production method according to claim 36, further comprising changing the angular distribution of the X-rays impinging on the mask. 45. An X-ray exposure apparatus comprising:
	description	1. Field of the Invention The present invention relates to an irradiation apparatus for irradiating particle beams or corpuscular rays to a location to be irradiated as well as an irradiation method using this apparatus. 2. Description of the Related Art Known methods of enlarging the irradiation field of an irradiation apparatus, which treats cancer by using such a kind of particle beams, generally include a double scatterer method and a Wobbler method. In the double scatterer method, there are arranged two scatterers through which a particle beam passes so that a uniform dose distribution can be formed. On the other hand, in the Wobbler method, a particle beam is irradiated on a scatterer while being moved in a circle by means of an electromagnet so that a uniform dose distribution can be formed in the vicinity of the center of the circle. The field of irradiation thus obtained is usually of an area of from about 15 cm×15 cm to about 20 cm×20 cm, which is sufficient for irradiation of a spot or location to be treated in a lot of cases (for instance, see a patent document: Japanese patent application laid-open No.H10-151211). However, there may also be some cases requiring irradiation fields larger than the above-mentioned one. For instance, larger flows are often required for elongated areas such as the oesophagus, the neck of the womb (cervix), and the area from the mandible to the shoulder. In these cases, the shape of a large irradiation field as required is not a square or a circle but a rectangle or an oval of from 15 cm×20 cm to 20 cm×25 cm or larger. One method of achieving such a large irradiation field, conceives that the distance from an irradiation field enlarging device to a location to be irradiated (hereinafter also referred to as the target) should be increased. However, in this case the rotating gantry used is a heavy structure having a diameter of about 10 m and a weight of about 200 tons, and at the same time it is a precision machine with its center of rotation designed to keep an accuracy of about +1/−1 mm. Thus, it is difficult to further enlarge such a structure even in terms of cost as well as accuracy. In addition, another method of achieving a large irradiation field is to strengthen the performance of an irradiation field enlarging device. In the Wobbler electromagnet, however, there arises a problem that when the magnetic field strength is increased to generate an alternating magnetic field, ac loss due to the eddy current generated in the iron core of the magnet becomes large, thereby heating the iron core to a high temperature. Moreover, although a strategy of lengthening the magnetic poles of the electromagnet can be conceived, too, it is undesirable from the viewpoint of keeping the rotating gantry small. On the other hand, in the case of using the double scatterer method, there is a technique of increasing the thickness of the scatterer to enlarge the irradiation field. In this case, however, beams passing through the scatterer are decelerated therein, so increasing the thickness of the scatterer shortens the range of the beams inside the target. Therefore, there is also a limit to the thickness of the double scatterer to be used. Thus, in order to increase the thickness of the double scatterer and to ensure the beam range inside the scatterer at the same time, it is inevitable to raise the beam energy, thus resulting in a larger particle accelerator. The object of the present invention is to provide an irradiation apparatus and method capable of providing a large irradiation field while ensuring the flatness of a radiation dose distribution in the irradiation field without strengthening the performance of the particle accelerator or the irradiation field enlarging device. Bearing the above object in mind, the present invention resides in an irradiation apparatus for irradiating a radiation beam transported from a particle accelerator to the target that is positioned on an irradiation table. A beam interruption part interrupts the radiation beam, and a position control part controls the position of the irradiation table in such a manner that the radiation beam is irradiated onto the entire surface of the target in a plurality of irradiation zones including an overlapping zone formed by a plurality of irradiations of the radiation beam. A “multileaf collimator control part” controls the radiation beam so as to provide a slope to a dose distribution in the overlapping zone of the respective irradiation zones such that the dose distribution is made flat over the entire surface of the target including the overlapping zone by the plurality of irradiations of the radiation beam. The above and other objects, features and advantages of the present invention will become more readily apparent to those skilled in the art from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings. Now, preferred embodiments of the present invention will be described below in detail while referring to the accompanying drawings. Embodiment 1. FIG. 1 shows the schematic construction of an irradiation system including irradiation apparatuses constructed in accordance with the principles of the present invention. FIG. 2 is a block diagram that shows an irradiation apparatus in the irradiation system of FIG. 1. FIG. 3 is a constructional view that shows a rotating gantry and an irradiation apparatus in the irradiation system of FIG. 1. FIG. 4 is a block diagram of a control unit in the irradiation apparatus of FIG. 3. FIG. 5 is a conceptual diagram that shows the structure of a multileaf collimator in the irradiation apparatus of FIG. 3. FIG. 6 is a conceptual diagram that shows the structure of a ridge filter in the irradiation apparatus of FIG. 3. FIG. 7 is a conceptual diagram that shows the structure of a compensating filter in the irradiation apparatus of FIG. 3. In the following, the irradiation apparatus will be described as being applied to a radiotherapy apparatus by way of example, but the present invention is not limited to this but is applicable to a variety of irradiation apparatuses. As shown in FIG. 1, the irradiation system includes a particle accelerator 1 for generating proton beams or carbon beams (C6+) and accelerating them into such an energy spectrum that each beam has a desired range in the body of a patient 4 to be treated, a beam transport system 3 for transporting the beams to respective treatment chambers 2, a plurality of cylindrical rotating gantries 5 provided one for each treatment chamber 2 for changing the directions of irradiation of the beams so that a patient 4 in each treatment chamber 2 can be irradiated by a corresponding beam from a desired direction of the patient 4, and a plurality of irradiation apparatuses 6 for irradiating the beams to the corresponding patient 4. The beam is transported from the particle accelerator 1 to the respective treatment chambers 2 in a finely focused state called the pencil beam. Each patient 4 is fixedly held on an irradiation table 7 in a corresponding treatment chamber 2. In certain cases, fixed beam lines through horizontal ports, vertical ports or the like may be used instead of the rotating gantries 5. Also, as illustrated in FIG. 2, each of the irradiation apparatuses 6 includes a beam interruption part 8 for performing a plurality of irradiations of a radiation beam, a position control part 9 for controlling the position of the beam in such a manner that the entire surfaces of all locations to be irradiated in a plurality of irradiation zones including overlapping areas formed by a plurality of irradiations, and a multileaf collimator control part 10 for providing a slope to the dose distribution in the overlapping areas of the irradiation zones formed by the plurality of irradiations, so that the dose distribution over the entire surfaces of the locations to be irradiated including the overlapping areas is made flat or uniform by the plurality of irradiations of the radiation beam. The beam interruption part 8 includes a dose monitor 11 for measuring the amount of dose and interrupting the radiation beam when the dose amount thus measured reaches a predetermined value, and a beam interrupter 12 for controlling the dose monitor 11. The position control part 9 includes an irradiation table 7 that is movable while carrying a patient thereon, and a position controller 13 for moving the irradiation table 7 so that the location of the patient to be irradiated can be adjusted to a desired position which is irradiated by the radiation beam. The multileaf collimator control part 10 includes a multileaf collimator 14 for forming an irradiation area of a desired shape and a desired dose distribution by variably shielding at least part of the radiation beam, and a multileaf collimator controller 15 for controlling the multileaf collimator 14. The multileaf collimator controller 15 controls the multileaf collimator 14 in such a manner that the irradiation zones formed by the irradiations of the radiation beam are shaped into desired configurations, respectively, and a proper slope is given to the dose distribution in each of the overlapping areas of the respective irradiation zones, whereby the dose distribution over the entire surfaces of the locations to be irradiated including the overlapping areas are made flat or uniform by the plurality of irradiations of the radiation beam. As shown in FIG. 3, each of the irradiation apparatuses 6 also includes an irradiation part 6a, the irradiation table 7, a control unit 16 and a display 16a. Each irradiation apparatus 6 further includes an irradiation field enlarging device 17 for expanding the beam transported by the beam transportation system 3 so as to form an irradiation field, the dose monitor 11 for monitoring the exposure dose of corpuscular radiation included in the irradiation field and automatically interrupting the beam at the time when a prescribed amount of dose has been irradiated, a ridge filter 18 for controlling the dose distribution in the patient's body in a direction along the beam axis, i.e., in the direction of depth, a multileaf collimator 14 for cutting out an irradiation area suitable for treatment by shielding a part of the radiation beam, a compensating filter 19 for adjusting the range of the beam, an X-ray tube 20 for generating X rays, and an image intensifier 21. The image intensifier 21 may be replaced with an X-ray film or another imaging system. The control unit 16 includes a beam interrupter 12 for controlling the interruption of the beam by controlling the dose monitor 11, a multileaf collimator controller 15 for controlling the multileaf collimator 14 so as to form an irradiation area suitable for treatment in the locations to be irradiated, a display part 22 for processing an X-ray transmission image obtained from the image intensifier 21 thereby to display it on the display 16a, and a position controller 13 for controlling a drive unit that drives the irradiation table 7. The control unit 16 is arranged at a place away from a corresponding treatment chamber 2 so that an engineer or operator can perform adjustments through remote control while observing the display 16a. The irradiation part 6a creates a uniform dose distribution of the beam within the location or area to be irradiated by the use of the multileaf collimator 14, the irradiation field enlarging device 17, the ridge filter 18 and the compensating filter 19. Usually, the irradiation is planned such that the dose distributions in the respective targets in the location to be irradiated become uniform to within +/−2.5%. The irradiation field enlarging device 17 comprises a Wobbler electromagnet, a double scatterer or the like as used in the aforementioned conventional apparatus. The multileaf collimator 14 is composed of a structure called multiple leaves 23, as shown in FIG. 5. The multileaf structure 23 has such quality of material, thickness and structure as to prevent the passage of a beam (see arrow B) therethrough, and have a multiplicity of paired opposing leaves. The respective leaves of the multileaf structure 23 are able to move on a straight line independently of one another (see arrows R and L). Each of the leaves of the multileaf structure 23 is connected with an unillustrated drive unit and an unillustrated position detector for detecting the position of a corresponding leaf. Thus, by remotely controlling the leaves 23 individually, the irradiation zones of arbitrary configurations can be formed in the location to be irradiated. The drive units and the position detectors are controlled by the multileaf collimator controller 15. The ridge filter 18 is a device comprising a plurality of structural members called ridges 24 being arranged like a washboard as shown in FIG. 6, the thickness of the ridges 24 being changed depending upon its locations. The configuration of the ridges 24 is designed based on detailed calculations. The beam (arrow) passes through the ridge filter 18 of varying thickness after passage of the irradiation field enlarging device 17, whereby it is decelerated in proportion to the thickness of the ridge filter 18. Accordingly, the beam of substantially a single energy spectrum at the upstream side of the ridge filter 18 is turned into one of wide energy spectrum as it passes through the ridge filter 18. Furthermore, since the beam has various angles due to the scattering effect of the ridge filter 18 at the upstream side thereof, the beam with different energy spectrums reaches the patient 4 while its energy spectrums are being mutually mixed with one another at the downstream side of the ridge filter 18. The compensating filter 19 is called a bolus, as shown in FIG. 7, usually made of polyethylene, etc., and has a shape formed in a manner to adjust the range of the beam to the deepest portion of a target 25 to be irradiated. Therefore, the compensating filter 19 has its shape varied according to the direction in which the irradiation target 25 is irradiated, and hence it is prepared for each portion of the irradiation target 25. The compensating filter 19 is attached to an unillustrated rail-shaped mechanism mounted on the multileaf collimator 14. That is, the compensating filter 19, being fitted to an unillustrated holder beforehand, can be mounted to the multileaf collimator 14 by being caused to slide along the rail-shaped mechanism. The radiotherapy apparatus has an unillustrated treatment planning device for planning an irradiation treatment. An irradiation plan is prepared for each portion of the target 25 to be irradiated. For preparation of such a treatment plan, the direction of irradiation, the shape of the target 25 to be irradiated, etc., are input from a terminal of the treatment planning device based on the image information obtained by the X-ray computerized tomography (CT) of the irradiation target 25. The treatment planning device automatically calculates, based on the information, the degree of opening of the leaves 23 of the multileaf collimator 14, data for preparing the ridge filter 18 and the compensating filter 19 to be used, etc., and outputs the results to a file. When a radiation beam is irradiated to the target 25 to be irradiated, setting of a corresponding irradiation apparatus 6 is carried out based on this file. Each irradiation apparatus 6 includes a positioning part for accurately positioning a target 25 to be irradiated with respect to the beam in order to irradiate it with high accuracy. The positioning part is provided with an X-ray tube 20 for generating X rays and an X-ray film or image intensifier 21, and serves to drive the irradiation table 7 by referring to an X-ray transmission image thus obtained. The irradiation table 7 has an unillustrated drive unit for moving the irradiation table in a direction necessary for proper alignment or positioning. An operator can perform proper alignment of the target to be irradiated with respect to the beam by moving the irradiation table 7 through remote control while observing the X-ray transmission image. The positioning accuracy is usually in the range of from 0.5 mm to a few millimeters or so. Now, reference will be made to the enlargement of the irradiation field by means of the irradiation apparatus according to the first embodiment of the present invention. FIG. 8 is a plan view that shows the irradiation field of the irradiation apparatus according to the first embodiment of the present invention. FIGS. 9A and 9B are dose distribution charts of the irradiation field in cross section along line A—A of FIG. 8, wherein FIG. 9A shows dose distributions in respective irradiation zones, and FIG. 9B shows a total dose distribution over the entire irradiation zones. FIG. 10 is a plan view that shows parameters of the irradiation field according to the first embodiment of the present invention. FIG. 11 is a dose distribution chart in cross section along line A—A of FIG. 10. Here, note that the following explanation will be made with an assumption that. the outside shape of the target to be irradiated coincides with that of the irradiation field, and hence the irradiation field will be mainly referred to below but it also indicates the irradiated target, too. In addition, one irradiation means the irradiation of a radiation beam performed to one irradiation zone. One irradiation includes a plurality of partial irradiations which are carried out in succession by successively changing the outer peripheral configuration of each irradiation zone by moving a part of the leaves 23, as will be described later. The method of enlarging the irradiation field is carried out as follows. That is, a first irradiation zone and a second irradiation zone, partially overlapping with each other, are formed by the operation of the multileaf collimator controller 15. The target 25 to be irradiated is moved by the position controller 13 to a new position where a new irradiation zone is formed, partially overlapping with but different from the original location. The irradiation field is enlarged by irradiating a beam to the first irradiation zone and the second irradiation zone through the beam interrupter 12. Here, note that though in the following description, the multileaf collimator controller 15 will not be referred to upon explaining the movement of the leaves 23 of the multileaf collimator 14, it always controls the multileaf collimator 14. Similarly, though not explained explicitly, the irradiation of the radiation beam is controlled by the beam interrupter 12. Moreover, it is assumed in the following explanation that the configuration of each irradiation zone is a square. As shown in FIG. 8, the target 25 to be irradiated is covered by a first square-shaped irradiation zone 26 enclosed by a solid line and a second square-shaped irradiation zone 27 enclosed by a broken line. A portion or area, in which the first irradiation zone 26 and the second irradiation zone 27 overlap with each other, is called the overlapping zone 28, and those portions of the first and second irradiation zones 26, 27 which do not overlap with each other are called non-overlapping zones 29. In FIG. 8, the boundaries between the overlapping zone 28 and the non-overlapping zones 29 become straight lines, respectively, but they need not necessarily be straight lines and may be curved lines. The maximum opening of the irradiation zone when the leaves 23 of the multileaf collimator 14 are opened to a maximum size is a square. The amount of dose of the overlapping zone 28 between the first and second irradiation zones 26, 27 decreases along a slope approximated by a straight line from the non-overlapping zones 29 toward the overlapping zone 28. Here, in order to make the explanation easy to understand, the decreasing slope of the dose is approximated by not a stepped line but a straight line. That is, the leaves 23 of the multileaf collimator 14 are not moved stepwise but continuously. Furthermore, irradiation is performed such that the total dose distribution of the overlapping zone 28 between the first and second irradiation zones 26, 27 is flat, and the total amount of dose thereof becomes equal to the dose of the non-overlapping zones 29. Next, reference will be made to a method of obtaining the width of the overlapping zone 28 between the first and second irradiation zones 26, 27 partially overlapping with each other as well as a method of obtaining the step width of movement of the leaves 23. To ensure a wide irradiation field, the overlapping zone 28 should be decreased as much as possible, however, it is necessary to increase the overlapping zone 28 to a sufficient extent so as to decrease the error in the flatness of the dose distribution due to positioning errors below a predetermined value. As shown in FIG. 10, a symbol L1 designates the width of a maximum opening in the direction of the X axis when the leaves 23 of the multileaf collimator 14 are opened to a maximum, and L2 designates the width of a maximum irradiation field in the direction of the X axis when the two irradiation zones 26, 27 come to partially overlap with each other. The width Lo of the overlapping zone 28 in the X axis direction is given by the following expression (1) based on a positioning error dx and a flatness error r for the required flatness.Lo=dx/r (1) Further, the moving distance Lt of the irradiation table 7 is given by an equation in the form of Lt=L1−Lo. In addition, the width L2 of the maximum irradiation field has a certain relation established between the positioning error dx and the width Lo of the overlapping zone 28 in the direction of the X axis, as represented by the following expression (2).L2=2×L1−Lo=2×L1−dx/r (2) By using expression (2) above, the relation between the positioning error dx, the maximum irradiation field L2 and the width Lo of the overlapping zone as required are represented by the following Table 1 with assumptions of L1=150 mm and r=2.5%. Relations Between the Positioning Error and the Other Parameters PositioningMaximumOverlap betweenMoving distanceerrorirradiation rangeirradiation zonesof irradiation tabledx mmL2 mmLo mmLt mm0.5290101401280201301.5270301202260401102.525050100324060 903.523070 80422080 704.521090 605200100 50 For instance, when the positioning error dx is 3 mm, the required width Lo of the overlapping zone becomes 60 mm and the width L2 of the maximum irradiation field is obtained to be 240 mm. Then, a method of obtaining the step width of movement of the leaves 23 will be described. Though the positions of the leaves 23 have been explained as being made continuously variable in the foregoing description, reference will hereinafter be made to the positions of the leaves 23 being controlled in a stepwise manner. In order to keep the flatness error r of the dose distribution equal to or below a predetermined value, it is necessary to set the maximum step width s of the movement of the leaves 23 to a prescribed value of Lo×r. Additionally, as already stated, when considering multiple scattering which contributes to leveling the dose distribution, the error r in the dose flatness decreases. Next, reference will be made to the operational steps of the leaves to obtain the above-mentioned dose distribution. FIG. 12 is a conceptual diagram that explains the movement of the leaves 23 of the multileaf collimator 14 in the first embodiment. FIG. 13 is a plan view that explains the movement of the leaves 23 of the multileaf collimator 14 corresponding to the first irradiation zone in FIG. 12. FIG. 14 is a plan view that shows the state of the leaves 23 in FIG. 13 during movement thereof. FIG. 15 is a plan view that explains the movement of the leaves 23 of the multileaf collimator 14 corresponding to the second irradiation zone in FIG. 12. FIG. 16 is a plan view that shows the of the leaves 23 in FIG. 15 during movement thereof. Although for the sake of easy understanding in the following explanation, it is assumed that the configuration of the location to be irradiated is a parallelogram and that the direction of movement of the leaves 23 is along the X axis, the location to be irradiated may take another configuration. First of all, the dimensions (i.e., vertical and horizontal lengths) of the target 25 to be irradiated are measured, and the width Lo of the overlapping zone 28 and the step width s are determined according to Table 1 above by using the positioning error dx and the flatness error r measured in advance, as described above. Then, the first irradiation zone 26 and the second irradiation zone 27 are set along the major or longitudinal axis of the target 25 to be irradiated. The first irradiation zone 26 is first irradiated and the second irradiation zone 27 is then irradiated with the direction of movement of the leaves 23 of the multileaf collimator 14 being set in parallel with the slope of the dose. FIG. 13 is a plan view that shows the positions of the leaves 23 when the irradiation to the first irradiation zone 26 is started. It is assumed that the center of the width L1 of the maximum opening of the leaves 23 of the multileaf collimator 14 enclosed by the thick solid line on the X axis is X=0, and that the x coordinate of the end face of each of the leaves 23 is defined at the widthwise center thereof with the x coordinates of the end faces of i-th left-hand and i-th right-hand ones of the leaves 23 being represented by XL(i) and XR(i), respectively. It is also assumed that the x coordinate of the left-hand end face of the overlapping zone 28 is X. An override is provided to the leaves 23 so that the right-hand and left-hand leaves can move to the left or right beyond X=0. In addition, it is further assumed that the rightward operation limit of the left-hand leaves is represented by XLIML and the leftward operation limit of the right-hand leaves is represented by XLIMR, and that the x coordinates of the left-hand end face and the right-hand end face of the location to be irradiated in each leaf are represented by XTARL(i) and XTARR(i), respectively. It is also assumed that the x coordinates of the right-hand end face and the left-hand end face of each of those left-hand and right-hand leaves which do not lie in the location to be irradiated are 0. When the first irradiation zone 26 is irradiated, most of the right-hand leaves perform the same operation except for a part thereof, so the x coordinates XR(i) of the left-hand end faces of the right-hand leaves can be placed with a common coordinate XR, whereas when the second irradiation zone 27 is irradiated, the left-hand leaves can be similarly defined with a common coordinate XL. The initialization of the leaf position in the first irradiation zone 26 is given by the following expressions (3) through (6). Here, it is assumed that the x axis in FIG. 13 is positive to the right from the origin, and negative to the left from the origin.XL(i)=min (XTARL(i), XLIML) (3)XR=X* (4)R(i)=max(XR, XL(i)) (5)XR(i)=min(XR(i), XTARR(i)) (6) Under the above conditions, when it is detected by the dose monitor 11 that a fixed dose has been irradiated, the beam is stopped. This state is called “partial dose completion”. Then, the “partial dose completion” is reset, and the position of the right-hand leaves is moved stepwise to the right by a step width s, as indicated by the following expressions (7) through (9), so that irradiation is carried out until the “partial dose completion” is reached.XR=XR+s (7)XR(i)=max(XR, XL(i)) (8)XR(i)=min(XR(i), XTARR(i)) (9) The state in which the leaves 23 have been moved halfway to the right is shown in FIG. 14. By repeatedly moving the leaves 23 stepwise to the right by the step width s in this manner, those of the right-hand leaves 23 of which left-hand end faces have reached the right-hand end face of the target 25 to be irradiated are stopped in their rightward movement, and when the XR* has reached the right-hand end face of the first irradiation zone 26, the irradiation of the first irradiation zone 26 is ended. Subsequently, the irradiation table 7 is moved by a prescribed distance Lt, and the second irradiation zone 27 is irradiated. The procedure for this case is that the operation of the first irradiation zone 26 is carried out symmetrically with respect to the x axis. That is, the leaf positions are initialized according to the following expressions (10) through (13). The initial settings of the leaves 23 are shown in FIG. 15.XR(i)=max(XTARR(i), XLIMR) (10)XL=X (11)XL(i)=min(XL, XR(i)) (12)XL(i)=max(XL(i), XTARL(i)) (13) Irradiation is carried out until the “partial dose completion” is obtained, whereafter the beam is stopped and the positions XL(i) of the left-hand leaves 23 are moved stepwise to the left by the step width s according to the following expressions (14) through (16).XL=XL−s (14)XL(i)=min(XL, XR(i)) (15)XL(i)=max(XL(i), XTARL(i)) (16) The state in which the leaves 23 have been moved halfway to the left is shown in FIG. 16. By repeatedly moving the leaves 23 stepwise to the left by the step width s in this manner, those of the left-hand leaves 23 of which right-hand end face reaches the left-hand end face of the target 25 to be irradiated are stopped in their leftward movement, and when the XL* has reached the left-hand end face of the second irradiation zone 27, the irradiation of the second irradiation zone 27 is ended, thus completing the entire irradiation. Now, reference will be made to the advantageous effects of the present invention. FIGS. 17A and 17B show individual and total dose distributions, respectively, in case where the two irradiation zones are disposed too near to each other in the first embodiment. FIGS. 18A and 18B show individual and total dose distributions, respectively, in case where the two irradiation zones are disposed too far from each other in the first embodiment. FIG. 19 is a plan view of an irradiation field having two irradiation zones 30, 31 without any overlapping zone, in which the dose distributions in the first irradiation zone 30 and the second irradiation zone 31 are flat over all the entire zones. FIGS. 20A and 20B show individual and total dose distributions, respectively, in cross section along line B—B when the two irradiation zones 30, 31 in FIG. 19 are in contact with each other at their boundary. FIGS. 21A and 21B are individual and total dose distributions, respectively, in cross section along line B—B when the two irradiation zones in FIG. 19 are separated from each other. FIGS. 22A and 22B are individual and total dose distributions, respectively, in cross section along line B—B when the two irradiation zones in FIG. 19 partially superpose with each other. The relative positions of the first irradiation zone 26 and the second irradiation zone 27 might be shifted due to various factors. However, it is understood that, even in such a case, the variation of the total dose in the overlapping zone 28 can be limited according to the present invention. That is, even if the two irradiation zones are disposed too near with respect to each other, the flatness of the total dose still remains within tolerance, as shown in FIGS. 17A and 17B. Also, even if the two irradiation zones are disposed too far away from each other due to a deviation in the positioning thereof, the flatness of the total dose similarly remains within tolerance, as shown in FIGS. 18A and 18B. In contrast to this, when patch field irradiations are carried out simply as shown in FIG. 19, there will take place an overlapping area or a separated area due to a positioning deviation or shift, thus resulting in an insufficient degree of flatness of the dose distribution. If the two irradiation zones are too far away from each other, there will take place a cold spot, as shown in FIGS. 21A and 21B, whereas if the two zones are too near to each other, there will take place a hot spot, as shown in FIGS. 22A and 22B. In both of these cases, the total dose varies in the range of +/−100% with respect to a desired dose, which greatly exceeds a normal tolerance range of +/−2.5%. In the above explanation about the advantageous effects; no consideration has been given to the effect of scattering. Accordingly, reference will hereinafter be made to the advantageous effects of the present invention by using rough values while taking account of the scattering effect. Here, note, however, that the scattering effect is less in the vicinity of the patient's body surface, so the discussion thus far is generally applicable to the dose distribution in the vicinity of the body surface. In the deep interior of the body, the divergence or spread of the beam due to multiple scattering can be approximated by a Gaussian distribution with a standard deviation σ. The maximum range of a proton beam with an energy of 250 MeV is about 37 cm in water, and scattering becomes a Gaussian distribution with a standard distribution σ of about 8 mm. In FIGS. 22A and 22B, assuming that the position error of overlapping is 3 mm and an excess dose at the hot spot is 100 units/mm for instance, an integrated amount of the excess dose becomes about 300 units. Given a Gaussian distribution for scattering of the above condition, it can be represented by the following expression (17), which is standardized to keep the integrated excess dose of 300 units.f(x)=300/[sqrt(2π) σ] exp(−x2/2σ2) (17) Also, in case of σ=8 mm, it can be represented by the following expression (18).f(x)=15.0 exp(−x2/2σ2) (18) In other words, at x =0, the excess dose will be made flat up to about 15 units/mm. However, it is understood that with such simple overlapping, the nonuniformity of the dose due to the positioning error is large even when the excess dose is maximally flattened by the multiple scattering. Since this irradiation apparatus is able to create a slope gradient of the dose in the overlapping portion of the two irradiation zones, the irradiation field can be enlarged and the flatness of the dose distribution can be improved easily. In addition, since the dose slope can be approximated by a straight line, the operation or manipulation of the leaves corresponding to the overlapping zone of each of the irradiation zones can be facilitated. Moreover, since the dose slope is parallel to the moving direction of the leaves, it is possible to achieve a straight slope by pulling out the leaves at a constant speed. Further, since the leaves can be driven in a stepwise manner, it is possible to simplify the construction of the drive unit for driving the leaves. Furthermore, the irradiation field can be nearly shaped into the configuration of the location to be irradiated by changing the moving pattern of the leaves, whereby the irradiation apparatus becomes able to have a greater degree of freedom. Still further, the influence of radiation on the operators and technologists can be reduced by manipulating the multileaf collimator through remote control. Besides, the radiotherapy apparatus provided with such irradiation apparatuses is able to treat a large target or area, an elongated target or area, etc. Here, note that although one example has been described in which the slope of the dose distribution is approximated by a straight line, it is similarly possible to enlarge the irradiation field even if approximated by a curved line. Embodiment 2. FIGS. 23A through 23D are plan views explaining the movement of the leaves of a multileaf collimator in an irradiation apparatus according to a second embodiment of the present invention, wherein FIG. 23A shows the initial positions of the leaves in which they are all closed; FIG. 23B shows that a first pair of leaves are opened with the remaining leaves being closed; FIG. 23C shows that a second pair of leaves are subsequently opened with the remaining leaves other than the first and second pairs being closed; and FIG. 23D shows that the last pair of leaves are finally opened. In the first embodiment, the direction in which the leaves are driven to move is parallel to the slope of the dose distribution, but this second embodiment is constructed such that the moving direction of the leaves is perpendicular to the slope of the dose distribution. In this case, each time a predetermined amount of dose is irradiated with partial irradiation, i.e., each time the irradiation of a partial dose is completed, the leaves 23 covering the overlapping zone are opened sequentially in the order from the leaves of the greatest dose requirement to the leaves of the least dose requirement. Specifically, in FIGS. 23A through 23D, the leaves 23 are opened sequentially from a pair of leaf 1 and leaf A. After the irradiation of the first irradiation zone 26 is finished in this manner, the irradiation table 7 is moved to a prescribed position where the second irradiation zone 27 is irradiated according to a symmetrical or similar procedure. In this second embodiment, a minimum step of the slope of the dose distribution is decided depending on a leaf width (i.e., the width of each leaf), it is necessary to determine the width of the overlapping zone in consideration of the leaf width s, as shown in Table 1. Such an irradiation apparatus can adjust the slope of the dose distribution of the overlapping zone by a step width comprising the leaf width, and hence such an adjustment can be made merely by pulling put the leaves and hence is not subjected to the influence of the positioning accuracy of the leaves. Thus, an error in the flatness of the dose distribution is decided by the leaf width alone, thereby making it possible to enhance the accuracy of the dose distribution flatness. Further, since the slope of the dose distribution is perpendicular to the moving direction of the leaves, the positional adjustment of the plurality of irradiation zones can be achieved only by adjusting the leaf positions. Embodiment 3. FIGS. 24A and 24B show individual and total dose distributions, respectively, when an irradiation apparatus according to a third embodiment of the present invention is used. In the above-mentioned first embodiment, the dose in the overlapping zone has been decreased at a constant slope from the non-overlapping zone toward its adjoining irradiation zones, but according to this third embodiment, in order to reduce the flatness in the dose distribution in an important area 32 in which the dose distribution flatness is particularly critical, the slope of the dose distribution in the important area 32 is made gradual, with the dose distribution slope in the other portions of the overlapping zone being made steep in comparison with that in the important area 32, as shown in FIGS. 23A through 23D. This irradiation apparatus is able to make the overlapping error of the dose in the overlapping zone smaller for concentrated administration thereof. Although in the foregoing description, the dose distribution changes according to a slope approximated by a straight line, similar advantageous effects will be obtained even if the dose distribution changes according to a slope approximated by a polygonal line, a curved line, etc., other than a straight line. Embodiment 4. FIG. 25 is a plan view of an irradiation field when an irradiation apparatus according to a fourth embodiment of the present invention is used. FIG. 26 is a dose distribution chart of this irradiation field. FIG. 27 is a plan view that shows the movement, parallel to the dose slope, of leaves of a multileaf collimator in the irradiation apparatus according to the fourth embodiment of the present invention. FIG. 28 is a dose distribution chart of an irradiation zone irradiated in FIG. 27. FIG. 29 is a plan view that shows the movement, perpendicular to the dose slope, of the leaves of the multileaf collimator in the irradiation apparatus according to the fourth embodiment of the present invention. FIG. 30 is a dose distribution chart of an irradiation zone irradiated in FIG. 29. FIG. 31 is a plan view of an irradiation field when the irradiation apparatus according to the fourth embodiment of the present invention is used. FIG. 32 is a dose distribution chart of the irradiation field in FIG. 31. In this fourth embodiment, three irradiation zones are employed in combination to further expand or enlarge the irradiation field, as shown in FIG. 25. In this case, a first irradiation zone 33 and a third irradiation zone 34 are similar to the first and second irradiation zones in the first embodiment, but a second irradiation zone 35 exhibits a triangular dose distribution. Irradiations to the first irradiation zone 33 and the third irradiation zone 34 can be made by moving the leaves in a manner similar to that of the above-mentioned first or second embodiment so that dose distributions in the overlapping zones of the first and third irradiation zones 33, 34 can be properly sloped. Then, reference will be made to the operation of the leaves with respect to the second irradiation zone 35 when the leaves are caused to move in a direction parallel to the dose slope, while referring to FIG. 27. The initial positions of the leaves are set to the boundaries of a flat area of the central portion, and the leaves are successively moved to open each time the irradiation of a partial dose has been completed. In addition, FIG. 29 shows the procedure in the operation of the leaves in case where the leaves are driven to move in a direction perpendicular to the dose slope. As shown in this figure, leaves 1 through 10 at one side and leaves A through K at the other side are sequentially moved to open in a pair of corresponding leaves at opposite sides each time the irradiation of a partial dose has been expired. Moreover, when the slopes of the overlapping zones in FIG. 27 are made more gradual, the overlapping zones become further larger, as shown in FIG. 31. When the overlapping zones come to occupy more than a half of the maximum opening of the multileaf collimator, the three irradiation zones 33, 34 and 35 overlap with one another in an area of X2. Here, as shown in FIG. 32, let us assume that a symbol m represents the gradient of each dose slope portion in the second irradiation zone 35; L represents the width of the maximum opening of the multileaf collimator; X1 represents the width of each dose slope portion in the second irradiation zone 35; and X2 represents the width of a dose constant portion in the second irradiation zone 35. For the purpose of irradiating the greatest area, the widths of the first, second and third irradiation zones are set to L, respectively. In this case, the relations of these parameters are represented by the following expressions (19) and (20):L=(2*X1+X2) (19)M(X1+X2)=1 (20)X1 and X2 are given by the following expressions (21) and (22) from expressions (19) and (20) above.X1=(L−1)/m (21)X2=2/(m−L) (22) Such an irradiation apparatus provides a wider irradiation field than the case where only two irradiation zones are overlapped with each other. Further, by making the slopes of the overlapping zones more gradual, the overlapping zones can be further increased, thereby further improving the flatness of the total dose distribution. Embodiment 5. FIG. 33 is a plan view that shows the movement of leaves of a multileaf collimator in an irradiation apparatus according to the fifth embodiment of the present invention. FIG. 34 is a plan view that shows the state of the leaves of FIG. 33 in the course of their movement. In a diseased part of the patient's body, there is a portion which should not be subjected to irradiation, being located like an isolated island while being surrounded by the target 25 to be irradiated. Thus, upon such irradiation, it becomes necessary to provide a non-irradiation zone 36 in the target 25 to be irradiated, as shown in FIG. 33. For instance, it is the case where the dose to the spinal cord is desired to be reduced in the irradiation of the trunk of the body. In this case, by dividing the area to be irradiated into a first irradiation zone 26 and a second irradiation zone 27 astride the non-irradiation zone 36, irradiation can be made in an area surrounding the outer periphery of the non-irradiation zone 36 by using the control procedure as described in the first embodiment. Such an irradiation apparatus can perform irradiation to the location to be irradiated, which is lying around a vital internal organ or radiation-sensitive internal organ such as the spinal cord, which is surrounded by the target and located like an isolated island. Embodiment 6. FIG. 35 is a cross sectional view of a compensating filter in an irradiation apparatus according to the sixth embodiment of the present invention. FIGS. 36A through 36C are schematic views illustrating the movement of the compensating filter in FIG. 35, wherein FIGS. 36A and 36C show the different positional positions of the compensating filter with respect to an irradiation beam, and FIG. 36B is a cross sectional view taken along line A—A in FIG. 36A. FIG. 37 is a cross sectional view of a filter driving mechanism for moving the compensating filter of FIG. 35 and a filter position verification mechanism. In the past, in order to irradiate an irradiation target 25 of a varying three-dimensional configuration, as shown in FIG. 35, compensating filters 37, 38 are prepared for a first irradiation zone and a second irradiation zone, respectively, and are replaced one with the other upon irradiation to each of the irradiation zones. However, separate preparations of two kinds of compensating filters 37, 38 are costly, and the replacement work of the compensating filters 37, 38 has to be done during the irradiation, incurring the time and trouble of an operator. Thus, the irradiation apparatus 6 according to the sixth embodiment includes a compensating filter 39 corresponding to the entire irradiation target 25, and a filter driving mechanism 40 for moving the compensating filter 39 so as to irradiate the second irradiation zone after irradiation of the first irradiation zone. The filter driving mechanism 40 is provided with a pair of rails 42 mounted to a multileaf collimator frame 41, a holder 43 being slidable along the rails 42 with the compensating filter 39 attached thereto, and a drive unit 44 for driving the holder 43. The drive unit 44 comprises a pulse motor, but it may be a well-known system such as a servo motor, an air cylinder, or the like. Further, if a filter position verification mechanism 45 is attached to the filter driving mechanism 44 so as to automatically verify the position of the compensating filter 39 in each of the irradiation zones, it becomes a measure for prevention of mis-irradiation, thereby making it possible to improve the safety of the irradiation apparatus 6. The filter position verification mechanism 45 counts and administers the number of pulses of the drive unit 44 in the form of a pulse motor from the origin position so as to control the operation of the drive unit 44. Here, note that in cases where measurements are not made by a potentiometer or remote control is not made, there may be used a known system such as a position reading mechanism in which a plurality of latches are arranged in several stages on the mounting rails so that the position of the compensating filter can be read by the use of switches provided on the latches, respectively. With such an irradiation apparatus, the two irradiation zones can be handled by moving only the single compensating filter to the right and left, as a result of which the manufacturing cost of the compensating filter can be reduced and the frequency of replacement thereof can be decreased as well, thereby alleviating the load on the part of the patient and operator. Furthermore, provision of the filter driving mechanism serves to achieve improvements in the operation or manipulation at the time of replacement of the compensating filter as well as preventing the filter from falling around the patient. In addition, provision of the filter position verification mechanism also serves to improve the safety against mis-irradiation. In the above description, irradiation to the two irradiation zones have been carried out by the single common compensating filter, but when three or more irradiation zones are irradiated, it is similarly possible to accommodate these irradiation zones by a common single, or reduced number of, compensating filter(s). As can be seen from the foregoing, the present invention provides the following advantages. According to the present invention, there is provided an irradiation apparatus for irradiating a radiation beam transported from a particle accelerator onto a target to be irradiated that is positioned on an irradiation table. The irradiation apparatus includes: a beam interruption part for interrupting the radiation beam; a position control part for controlling the position of the irradiation table in such a manner that the radiation beam is irradiated onto the entire surface of the irradiation target in a plurality of irradiation zones including an overlapping zone formed by a plurality of irradiations of the radiation beam; and a multileaf collimator control part for controlling the radiation beam so as to provide a slope to the dose distribution in the overlapping zone of the respective irradiation zones such that the dose distribution is made flat over the entire surface of the target including the overlapping zone by the plurality of irradiations of the radiation beam. With this arrangement, it becomes possible to irradiate a wide location or area, and in such a case, an excellent or desired flatness of the dose distribution can be obtained with ease. While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.
	summary
	claims	1. A method of manufacturing at least a portion of a focused grid or focused collimator, having at least one layer comprising a plurality of walls defining openings therein, and being adaptable for use with an electromagnetic energy emitting device, the method comprising the steps of:placing a photoresist material onto a substrate base;covering the photoresist with a mask comprising a plurality of apertures therein;irradiating the mask and the photoresist material with rays of energy from a point source, wherein at least some of the rays of energy enter at least some of the plurality of apertures in the mask and strike portions of the photoresist material;removing the portions of the photoresist material that were not irradiated by the rays of energy to create openings in the photoresist material; andplacing a wall material in the openings in the photoresist material to form walls of a focused grid or focused collimator. 2. The method as claimed in claim 1, wherein the placing of the wall material comprises the step of electroforming the wall material on the exposed areas of the substrate base. 3. The method as claimed in claim 1, wherein the placing of the wall material comprises electroplating the wall material on the exposed areas of the substrate base. 4. The method as claimed in claim 1, wherein the wall material comprises at least one of nickel, nickel-iron, copper, silver, gold, lead, tungsten, uranium, and electroplating, electroforming or casting material. 5. The method as claimed in claim 1, wherein the substrate base comprises a graphite substrate. 6. The method as claimed in claim 1, further comprising:forming a plurality of layers of the wall by performing the steps of claim 1; andstacking the layers to form the focused grid or focused collimator. 7. The method as claimed in claim 1, further comprising:forming a plurality of pieces of the wall by performing the steps of claim 1; andassembling the pieces to form the focused grid or focused collimator. 8. The method as claimed in claim 1, further comprising removing the substrate base from the photoresist material. 9. The method as claimed in claim 8, wherein the removing of the substrate comprises abrading the substrate base from the layer of the focused grid or focused collimator. 10. The method as claimed in claim 1, wherein at least portions of the photoresist material are removed from the wall material. 11. The method as claimed in claim 1, further comprising repeating the covering of the photoresist material with the mask and the irradiating rays of the mask and the photoresist material with the rays of energy. 12. The method as claimed in claim 1, wherein the irradiating of the mask and the photoresist material with the rays of energy comprises irradiating the mask and the photoresist material with a focused cone beam from the point source. 13. The method as claimed in claim 12, wherein the focused cone beam comprises ultra-violet rays. 14. The method as claimed in claim 12, wherein the focused cone beam comprises x-rays. 15. The method as claimed in claim 1, wherein the irradiating of the mask and the photoresist material with the rays of energy comprises irradiating the mask and the photoresist material with parallel beams from the point source. 16. The method as claimed in claim 15, wherein the irradiating of the mask and the photoresist material with the rays of energy comprises impinging the mask, the photoresist material and the substrate from a point source at predetermined angles for each position of the mask to obtain desirable angles of the walls relative to the substrate. 17. The method as claimed in claim 16, further comprising moving the mask, the photoresist material and the substrate in an arc with respect to a first fixed imaginary point to form at least a portion of the wall. 18. The method as claimed in claim 16, further comprising moving the mask, the photoresist material and the substrate in an arc with respect to a second fixed imaginary point to form another portion of the wall, wherein the second fixed imaginary point is different from the first fixed imaginary point. 19. The method as claimed in claim 16, further comprising moving the mask, the photoresist material, and the substrate with respect to an imaginary point located at infinity to form at least a portion of the wall. 20. The method as claimed in claim 1, wherein the rays of energy comprise ultra-violet rays. 21. The method as claimed in claim 1, wherein the rays of energy comprise x-rays. 22. The method as claimed in claim 1, wherein the substrate base comprises a silicon substrate coated with a plating base.
	description	This application is a divisional of U.S. Patent Application No. 11/995,744 filed on Jan. 15, 2008 now U.S. Pat. No. 8,003,967, which is a National Stage Application of PCT/US2006/29056 filed on Jul. 26, 2006, which claims priority to U.S. Provisional Patent Application No. 60/702,942 filed on Jul. 27, 2005, the entire disclosures of all these applications being incorporated herein by reference. The present invention relates generally to radiation-shielding devices for radioactive materials and, more particularly, to radiation-shielding assemblies used to enclose radioactive materials used in the preparation and/or dispensing of radiopharmaceuticals. Nuclear medicine is a branch of medicine that uses radioactive materials (e.g., radioisotopes) for various research, diagnostic and therapeutic applications. Radiopharmacies produce various radiopharmaceuticals (i.e., radioactive pharmaceuticals) by combining one or more radioactive materials with other materials to adapt the radioactive materials for use in a particular medical procedure. For example, radioisotope generators may be used to obtain a solution comprising a daughter radioisotope (e.g., Technetium-99m) from a parent radioisotope (e.g., Molybdenum-99) which produces the daughter radioisotope by radioactive decay. A radioisotope generator may include a column containing the parent radioisotope adsorbed on a carrier medium. The carrier medium (e.g., alumina) has a relatively higher affinity for the parent radioisotope than the daughter radioisotope. As the parent radioisotope decays, a quantity of the desired daughter radioisotope is produced. To obtain the desired daughter radioisotope, a suitable eluant (e.g., a sterile saline solution) can be passed through the column to elute the daughter radioisotope from the carrier. The resulting eluate contains the daughter radioisotope (e.g., in the form of a dissolved salt), which makes the eluate a useful material for preparation of radiopharmaceuticals. For example, the eluate may be used as the source of a radioisotope in a solution adapted for intravenous administration to a patient for any of a variety of diagnostic and/or therapeutic procedures. In one method of obtaining a quantity of the eluate from the generator, an evacuated container (e.g., an elution vial) may be connected to the generator at a tapping point. For example, a hollow needle on the generator can be used to pierce a septum of an evacuated container to establish fluid communication between the elution vial and the generator column. The partial vacuum of the container can draw eluant from an eluant reservoir through the column and into the vial, thereby eluting the daughter radioisotope from the column. The container may be contained in an elution shield, which is a radiation-shielding device used to shield workers from radiation emitted by the eluate after it is received in the container from the generator. After the elution is complete, the activity of the eluate may be calibrated by transferring the container to a calibration system. Calibration may involve removing the container from the shielding assembly and placing it in the calibration system to measure the amount of radioactivity emitted by the eluate. A breakthrough test may be performed to confirm that the amount of the parent radioisotope in the eluate does not exceed acceptable tolerance levels. The breakthrough test may involve transfer of the container to a thin shielding cup (e.g., a cup that effectively shields radiation emitted by the daughter isotope but not higher-energy radiation emitted by the parent isotope) and measurement of the amount of radiation that penetrates the shielding of the cup. After the calibration and breakthrough tests, the container may be transferred to a dispensing shield. The dispensing shield shields workers from radiation emitted by the eluate in the container as the eluate is transferred from the container into one or more other containers (e.g., syringes) for use later in the radiopharmaceutical preparation process. Dispensing shields are generally lighter weight and easier to handle than elution shields for the dispensing process because each of the containers may be used to fill multiple containers (e.g., off and on over the course of a day) and it is generally desirable to place the shielded container upside down on a work surface (e.g., tabletop surface) during the idle periods between transfer of the eluate into one container and the next. Prior art elution shields are generally not conducive for use as dispensing shields because, among other reasons, they may be unstable when inverted. For example, some elution shields have a heavy base that results in a relatively high center of gravity when the elution shield is upside down. Further, some elution shields have upper surfaces that are not adapted for resting on a flat work surface (e.g., upper surfaces with bumps that would make the elution shield unstable if it were placed on a flat surface upside down). Radiopharmacies have addressed this problem by maintaining a supply of elution shields and another supply of dispensing shields. This solution necessitates a transfer of the container from an elution shield to a dispensing shield, which can undesirably expose a worker to radiation. The same generator may be used to fill a number of containers before the radioisotopes in the column are spent. The volume of eluate needed at any time may vary depending on the number of prescriptions that need to be filled by the radiopharmacy and/or the remaining concentration of radioisotopes in the generator column. One way to vary the amount of eluate drawn from the column is to vary the volume of evacuated containers used to receive the eluate. For example, container volumes ranging from about 5 mL to about 30 mL are common and standard containers having volumes of 5 mL, 10 mL, or 20 mL are currently used in the industry. A container having a desired volume may be selected to facilitate dispensing of a corresponding amount of eluate from the generator column. Unfortunately, the use of multiple different sizes of containers is associated with significant disadvantages. For example, a radiopharmacy must either keep a supply of labels, rubber stoppers, flanged metal caps, spacers and/or lead shields in stock for each type of container it uses, or use shielding devices that can be adapted for use with containers of various sizes. One solution that has been practiced is to keep a variety of different spacers on hand to occupy extra space in the radiation shielding devices when smaller containers are being used. Unfortunately, this adds to the complexity and increases the risk of confusion because the spacers can get mixed up, lost, broken, or used with the wrong container and are generally inconvenient to use. For instance, some conventional spacers surround the sides of the containers in the shielding-devices, which is where labels may be attached to the containers. Accordingly, the spacers may mar the labels and/or adhesives used to attach the labels to the container resultantly causing the spacers to stick to the sides of the container or otherwise gum up the radiation-shielding device. Thus, there is a need for improved radiation-shielding assemblies and methods of handling containers containing one or more radioisotopes that facilitates safer, more convenient, and more reliable handling of radioactive materials produced for nuclear medicine. One aspect of the present invention is directed to a radiation-shielding assembly that may be used to shield a radioactive material in an elution process and/or in a dispensing process. The assembly includes a body having a cavity and an opening into the cavity defined therein. The assembly also includes a cap adapted for releasable attachment (e.g., via magnetism) to the body when the cap is in a first orientation relative to the body and for non-attached engagement with the body when the cap is in a second orientation relative to the body. Incidentally, a “non-attached engagement” or the like means that first and second structures interface but are not attached. An example of a non-attached engagement would be the interface of a drinking cup disposed on a coaster. Another aspect of the invention is directed to use of a radiation-shielding assembly. In this method, a cap of the radiation-shielding assembly is releasably attached to a body of the assembly to cover an opening into the body and to limit escape of radiation from inside the assembly. The cap is removed from the body and placed on an appropriate support surface (e.g., working surface). The body is inverted and placed on top of the cap so that the cap is in a different orientation relative to the body than it was when it was releasably attached to the body, thereby causing the cap and body to be in non-attached engagement. The body may be lifted from the cap to expose the opening. Another aspect of the invention is directed to a radiation-shielding assembly that can be used to shield an eluate (e.g., solution that includes a radioisotope from a radioisotope generator). The assembly has a body at least partially defining a cavity for receiving the eluate. There is an opening through the body into the cavity at an end of the body. The body is designed/configured to limit escape of radiation emitted by the radioisotope from the elution shield through the body. The assembly also has a base that may be releasably secured to the body at a second end thereof. The base has a sidewall extension portion aligned with the circumferential sidewall when the base is secured to the body. The sidewall extension portion of the base has a relatively lighter-weight construction in comparison to the circumferential sidewall of the body. For instance, the sidewall extension portion of the base may be made of a material exhibiting a first weight density, and the circumferential sidewall of the body may be made of another material having a second weight density greater than the first weight density. Another aspect of the invention is directed to a method of making an elution shield for a radioisotope received from a radioisotope generator. A body of the elution shield includes a radiation-shielding material and is formed to have a cavity for receiving the radioisotope therein. A base of the elution shield includes a material that would be substantially transparent to radiation emitted by the radioisotope. The material of the base is a relatively lighter-weight material than the radiation-shielding material of the body. The base is formed to connect to the body and extend the overall length of the elution shield to a length greater than the length of the body. Still another aspect of the invention is directed to a radiation-shielding assembly for holding any one of a set of containers that have different heights and that may be used to contain a radioactive substance. The assembly has a body at least partially defining a cavity for receiving a container. The assembly is preferably constructed to limit the escape of radiation emitted in the cavity from the assembly. The cavity has first and second opposite ends. The assembly also has a spacer that can be at least partially disposed in the cavity (e.g. at or near the second end of the cavity). The spacer is selectively adjustable to change the amount of space between a support surface of the spacer and the first end of the cavity by translation of the support surface so the support surface positions the containers in substantially the same location relative to the first end of the cavity. Yet another aspect of the invention is directed to a method of using a radiation-shielding assembly to handle containers that have different heights and which are used to hold a radioactive substance. A first container is placed in a cavity defined in the radiation-shielding assembly. A spacer is associated with the cavity and is utilized to position the first container at a predetermined location relative to an end of the cavity. The first container is subsequently removed from the cavity. The spacer is adjusted by moving the spacer along an axis of the cavity to change the amount of space between the spacer and the end of the cavity. A second container having a different height than the first container is placed in the cavity. The adjustment of the spacer results in the second container being positioned at substantially the same predetermined location as the first container was relative to the end of the cavity. Still another aspect of the invention is direction to a radiation-shielding assembly for container holding a radioactive eluate. The assembly has a body at least partially defining a cavity for receiving the container. There is an opening through the body into the cavity. The opening is sized to permit the container to be placed into and removed from the cavity. The body of the assembly is constructed to limit escape of radiation from the radioactive material through the body. The assembly also includes a locator in the cavity opposite the opening for at least assisting in locating the container in a predetermined position in the cavity. The locator may be characterized as a guide that can interface with one end of the container and that is shaped so that, upon interfacing with the end of the container, the collar may be used to at least generally steer or direct the container to the predetermined position in the cavity. The locator may include and of a wide range of materials. For instance, in some embodiments, the locator may include or be made entirely from a material that is substantially transparent to radiation. Another aspect of the invention is directed to a method of making a radiation shielding assembly for a container containing a radioactive eluate. A body of the assembly includes shielding material capable of substantially limiting passage of radiation through the material. The body is formed with a cavity for receiving the container of radioactive eluate. A locator is formed from a material that is substantially transparent to radiation so that the locator can be received in the cavity and engage the container when placed in the cavity to locate the container in (e.g., guide or steer the container toward) a predetermined position relative to the body in the cavity. Still another aspect of the invention is directed to a radiation-shielding assembly for holding any one of a set of containers having different heights that are used for containing a radioactive substance. The assembly has a body at least partially defining a cavity for receiving a container. The assembly also has a spacer adapted to be at least partially received in the cavity. The spacer can selectively be placed in the cavity to occupy space in the cavity to adapt the assembly for use with at least one of the smaller containers or removed from the cavity to adapt the assembly for use with at least one of the larger containers. The assembly may also have a base adapted for releasable connection to the body. The base may have a stowage receptacle defined therein that can receive the spacer when the spacer is removed from the cavity. Yet another aspect of the invention is a method of using a radiation-shielding assembly to hold containers having different heights that are used for containing a radioactive substance. A spacer is placed in a cavity of the assembly to adapt the assembly for use with a first container. The first container may be substantially enclosed in the cavity. The first container is subsequently removed from the cavity. The spacer may also be removed from the cavity to adapt the assembly for use with a second container that is taller than the first container. When not in use, the spacer may be stowed in a stowage receptacle formed in the assembly. The second container may be substantially enclosed in the cavity. Various refinements exist of the features noted in relation to the above-mentioned aspects of the present invention. Further features may also be incorporated in the above-mentioned aspects of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments of the present invention may be incorporated into any of the aspects of the present invention alone or in any combination. Corresponding reference characters indicate corresponding parts throughout the figures. Referring now to the figures, first to FIGS. 1-3 in particular, one embodiment of a radiation-shielding assembly of the present invention is shown as a rear-loaded dual-purpose radioisotope elution and dispensing shield, generally designated 101. The assembly 101 may enclose a container (e.g., eluate vial) containing a radioisotope (e.g., Technetium-99m) that emits radiation in a radiation-shielded cavity in the assembly, thereby limiting escape of radiation emitted by the radioisotope from the assembly. Thus, the assembly may be used to limit the radiation exposure to workers handling of one or more radioisotopes or other radioactive material. As shown in FIGS. 2 and 3, the illustrated assembly 101 generally has a body 103, a cap 105, a collar 107, and a base 109. The body 103 may include a circumferential sidewall 115 partially defining a cavity 117 adapted to receive a container C (shown in phantom). The cap 105 may be releasably attached to one end of the body 103 while the base 109 may be releasably attached to the other end of the body. The collar 107 may be received in the cavity 117, if desired, to help guide the container C into a desired position in the body 103 as it is loaded into the assembly 101. When assembled together, as shown in FIGS. 1 and 3, the body 103, cap 105, and base 109 may be used to enclose the container C in the cavity 117 of the assembly 101 and form a shielding unit that limits escape of radiation in the cavity 117 from the assembly 101. The sidewall 115 of the body 103 shown in the figures is substantially tubular, but the sidewall can have other shapes (e.g., polygonal) without departing from the scope of the invention. The sidewall 115 may be adapted to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the sidewall. For example, in one embodiment the sidewall 115 includes a radiation-shielding material (e.g., lead, tungsten, depleted uranium or another dense material). The radiation-shielding material can be in the form of one or more layers (not shown). Some or all of the radiation-shielding material can be in the form of substrate impregnated with one or more radiation-shielding materials (e.g., a moldable tungsten impregnated plastic). Those skilled in the art will know how to design the body 103 to include a sufficient amount of one or more selected radiation-shielding materials in view of the amount and kind of radiation expected to be emitted in the cavity and the applicable tolerance for radiation exposure to limit the amount of radiation that escapes the assembly 101 through the sidewall 115 to a desired level. One end of the body 103 may define a first opening 121 to the cavity 117 and a second end of the body 103 may define a second opening 123 to the cavity 117, as shown in FIG. 3. The second opening 123 may be sized greater than the first opening 121. For example, the first opening 121 can be sized to prevent passage of the container C therethrough and yet permit passage of at least a tip of a needle (not shown) therethrough (e.g., a needle on a tapping point of a radioisotope generator). The body 103 shown in the figures, for example, includes an annular flange 127 extending radially inward from the sidewall 115 near the top of the sidewall. (As used herein the terms “top” and “bottom” are used in reference to the orientation of the assembly 101 in FIG. 3 but does not require any particular orientation of the assembly or position of component parts.) An inside edge 129 of the flange 127 defines the first opening 121, which may be a substantially circular opening. The flange 127 may have a chamfer 131 to facilitate guiding of the tip of a needle toward a pierceable septum (not shown) of the container C received in the cavity. The flange 127 may be integrally formed with the sidewall 115 or manufactured separately and secured thereto. The flange 127 may include a radiation-shielding material, as described above, to limit escape of radiation from the assembly 101. However, the flange 127 can be substantially transparent to radiation without departing from the scope of the invention. The second opening 123 may be sized to permit passage of a container C therethrough for loading and unloading of containers from the assembly 101. The cap 105 may be removed from the assembly 101 as shown in FIG. 5 so that the container C in the cavity 117 of the assembly can be fluidly interconnected with a radioisotope generator through the now exposed opening 121. Incidentally, “fluidly interconnected” or the like refers to a joining of a first component to a second component or to one or more components which may be connected with the second component, or a joining of the first component to part of a system that includes the second component so that a substance (e.g., an eluant and/or eluate) may pass (e.g., flow) at least one direction between the first and second components. The cap 105 of the embodiment shown in the figures is reversible. When the cap 105 is in a first orientation relative to the body 103 (shown in FIGS. 1 and 3), the cap may be releasably attached to the body. When the cap 105 is in a second orientation relative to the body 103 (e.g., inverted as shown in FIGS. 6 and 6A), the cap 105 may be adapted for non-attached engagement with the body 103. More specifically, FIGS. 6 and 6A show the cap in the same orientation as in FIGS. 1-3 while the body has been inverted relative to the cap and placed upside down on the cap. The configuration of the assembly 101 in FIG. 3 may be characterized by some to be convenient for carrying the container C of radioactive eluate in the cavity 117 from one place to another with less concern about the cap 105 accidentally falling off the body 103 and unnecessarily exposing people to radiation than if the cap 105 were simply set unattached on top of the assembly 101. The configuration of the assembly 101 in FIGS. 6 and 6A may be found to be convenient for storing the container C of radioactive eluate in an inverted position during idle time between the dispensing of eluate from the container C in the assembly into another container (e.g., a syringe) used downstream in the radiopharmaceutical preparation process. In addition, some users may find that orientation convenient because it allows a person to access the container C simply by lifting the body 103 off the cap 105 to expose the first opening 121. For example, the container C can be accessed by lifting the body 103 with a single hand as shown in FIG. 7, leaving the other hand free to perform another action (e.g., hold a syringe) in preparation for the dispensing process. There are a number of ways to design a cap 105 to be releasably attachable to the body 103 in the first orientation and adapted for non-attached engagement with the body 103 in the second orientation. The cap 105 shown in FIGS. 4 and 4A, for example, includes a magnetic portion 137 that attracts the body 103 when the cap is in the first orientation, thereby resisting movement of the cap 105 away from the body. In some embodiments, the body 103 may be constructed of a material (e.g., an alloy comprising one or more magnetic metals) that is attracted by the magnetic portion 137 of the cap 105. In other embodiments, the body 103 includes a material having a relatively weaker attraction or no attraction to the magnetic portion 137 of the cap 105 and an attracting element (not shown) made of a material that has a relatively stronger attraction to the magnetic portion (e.g., iron or the like) molded into or otherwise secured to the body to enable the magnetic portion of the cap to attract the body. When the cap 105 is in the second orientation, however, the attraction of the magnetic portion 137 of the cap to the body 103 is sufficiently attenuated (e.g., by an increase in distance between the body and the magnetic portion of the cap, magnetic “shielding”, etc.) so that the weight of the cap is sufficient to freely separate the cap from the body when one of the body and the cap is urged away from the other. As shown in FIGS. 3 and 6A, for example, the cap 105 may be constructed so that the magnetic portion 137 thereof is positioned adjacent (e.g. in contact with) the body 103 when the cap engages the body in the first orientation (FIG. 3) and separated from the body (e.g., by a substantially non-magnetic material 139) when the cap engages the body in the second orientation (FIG. 6A). The cap and/or the body may be equipped with detents, snaps and/or friction fitting elements or other fasteners that are operable to releasably attach the cap to the base without use of magnetism in the first orientation and which are substantially inoperable to attach the cap to the body in the second orientation without departing from the scope of the invention. The cap 105 may be adapted to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the first opening 121 when the cap is releasably attached to the body 103 in the first orientation and when the cap is in non-attached engagement with the body in the second orientation. For example, the cap 105 may include one or more radiation-shielding materials (not shown), as described above. Those skilled in the art will be able to design the cap 105 to include a sufficient amount of one or more radiation-shielding material to achieve the desired level of radiation shielding. In order to reduce costs, radiation-shielding materials may be positioned at the center of the cap 105 (e.g., in registration with the first opening 121 when the cap is positioned relative to the body as shown in FIGS. 3 and 6), and the outer circumference of the cap may be made from less expensive and/or lighter-weight non-radiation-shielding materials, but this is not required for practice of the invention. The collar 107 (which, in some case, may be referred to as a container “locator” of sorts) may be placed in the cavity 117 to guide the container C into a desired and/or predetermined position as it is loaded into the cavity. For example, the collar 107 may be press fit into the cavity 117 so that the friction between the body 103 and the collar tends to hold the collar in the cavity. In other embodiments, the collar 107 may be secured to the body 103 by an adhesive or other suitable method of attachment. In yet other embodiments, the collar 107 may be an integral component of the body 103. The collar 107 may be adapted to assist in aligning the top of a container C with the first opening 121 of the body 103 to facilitate piercing of the container's septum by the tip of a needle on a radioisotope generator when the container is disposed in the cavity 117 of the body 103. In some embodiments, alignment of the top (e.g., mouth) of the container C with the first opening 121 may require the top of the container to be centered in the cavity 117, but the predetermined position to which the collar is constructed to guide the container can vary depending on the configuration of the particular assembly. In the embodiment shown in FIG. 3, the collar 107 may be position in the cavity 117 adjacent the first opening 121 and opposite the second opening 123. Referring to FIG. 3 in conjunction with FIGS. 17A-B, the collar 107 has an aperture 145 spanning between first and second sides of the collar. A first aperture opening is defined at the side of the collar 107 facing the second opening 123 of the body 103, and a second aperture opening of the collar is defined at the side of the collar facing the first opening 121 of the body. The aperture 145 may receive at least a part of a container C as it is loaded into the cavity through the second opening 123 in the body 103. The aperture 145 is shaped so that the collar 107 guides or steers the container C toward the predetermined position upon engagement of the inside of the collar 147 with the leading end of the container as it is being loaded into the cavity 117. For instance, the first opening of the aperture 145 may be greater in size than the second opening of the aperture. The aperture 145 of the collar 107 shown in FIGS. 17A and 17B is somewhat analogous to a funnel in that it is tapered. The collar 107 can have a different shape (e.g., be shaped to define a stepped or tiered aperture 145′ like the collar 107′ shown in FIGS. 18A and 18B) without departing from the scope of the invention. The top of the aperture 145 defined in the collar 107 may be shaped to engage or at least generally interface with about the top third of a cap 119a of the container C being held in the cavity 117, as shown in FIG. 3. It should be noted that other embodiments of the top of the aperture 145 may be shaped to engage or at least generally interface with more or less than about the top third of the cap 119a on the container C. As illustrated, the collar 107 is operable to align (e.g., center) a septum of the container C with the first opening 121. The portion of the container C that is engaged by the collar may be varied in size and/or location without departing from the scope of the invention. The collar 107 may be constructed of any appropriate material, such as a relatively inexpensive, lightweight, durable, low-friction material (e.g., polycarbonate). Moreover, the material may be substantially transparent to radiation. Indeed, since the body 103 of the assembly 101 generally includes radiation-shielding material, it may be undesirable to include radiation-shielding material in the collar 107 as well. In other words, the collar 107 of some embodiments may include radiation-shielding material only to the extent such radiation-shielding material is needed to attain a desired and/or required level of radiation protection for a specific application. Use of a material that is transparent to radiation for the make-up of the collar 107 may beneficially allow the weight and/or cost of the assembly to be reduced. Those skilled in the art will appreciate that the cost of machining a cylindrical cavity 117 in the body 103 may tend to be less than the cost of machining a cavity in the body shaped to form one or more positioning structures (e.g., shoulders) on the body to be used to guide containers in the same manner as the collar 107. Radiation-shielding materials can be difficult to machine and may tend to be more expensive than other materials that may be used for the collar 107. Further, the overall weight of the assembly may be reduced by making the collar 107 out of relatively lighter-weight material instead of relatively heavier-weight materials that may be used to make the body 103. It is understood, however, that the body 103 can be manufactured by any method (e.g., molding) without departing from the scope of the invention. Moreover, use of other types of locators instead of a collar is considered to be within the scope of the invention. Still further, some embodiments of the invention have collars that include radiation-shielding materials. The base 109 may be releasably secured to the body 103. As best seen in FIGS. 12 and 13, the base 109 shown in the figures includes an extension element 161, a base shielding element 163, and a spacer system 165. The extension element 161 may be a generally tubular structure having an open top end 171 adapted for making a releasable connection to the body 103 (e.g., adjacent the second opening 123) and a closed bottom end 173. The extension element 161 may be constructed of one or more relatively inexpensive, lightweight, durable materials, such as high-impact polycarbonate materials (e.g., Lexan®), nylon, and the like. The bottom end 173 of the extension element 161 may be outwardly flared to provide a wider footprint for added stability when the assembly 101 is placed base down on a work surface (as shown FIG. 1). The extension element 161 may be used to lengthen the assembly 101, including the combined length of the body 103 and the base 109. For example, the extension element 161 may include a circumferential sidewall 181 generally corresponding to the circumferential sidewall 115 of the body 103 as shown in FIG. 1. As those skilled in the art know, some radioisotope generators are designed to work with a shielding assembly having a particular minimum length (e.g., six inches). The extension element 161 may be used in combination with a body 103 that would otherwise be too short for a particular radioisotope generator to satisfy the minimum length requirement of that generator. The base extension element 161 may be transparent to radiation because other parts of the assembly 101 can be designed to achieve the desired level of radiation shielding. Use of a relatively lighter-weight (e.g., non-radiation-shielding) extension element 161 to provide the required length allows the assembly 101 to be lighter and/or less expensive compared to a similar assembly that is constructed of relatively heavier-weight and/or more expensive materials (e.g., radiation-shielding materials) along the entirety of the minimum length required by a particular radioisotope generator. There may be a void (illustrated herein as a receptacle 203) in the base for additional weight reduction. For example, in one embodiment of the invention, the overall weight is no more than about 4 pounds. In another embodiment, the weight is no more than about 3 pounds. Use of the relatively lightweight extension element 161 may also shift the center of gravity of the assembly 101 toward the end of the body 103 defining the first opening 121, making the assembly more stable when inverted for use as a dispensing shield (See, FIG. 6). The base 109 may be adapted for being releasably attached to the body 103 by a quick turn connection 191 (e.g., a connection in which the base may be secured to and/or released from the body by twisting the base relative to the body by no more than about 180 degrees) as is shown in FIG. 9. When the base 109 is twisted to release it from the body 103, the quick turn connection 191 may be adapted to provide a positive indication that the base has been twisted far enough relative to the body to permit the assembly 101 to be opened. By enabling separation of the base 109 from the body 103 by twisting the base through a relatively small angle relative to the body (e.g., about 45 degrees in the illustrated embodiment) and/or providing a positive indication that the assembly 101 can be opened by pulling the base away from the body, some embodiments of the invention may help reduce the risk of accidentally dropping the base (and perhaps letting a container filled with and/or contaminated by radioactive material fall out of the body) in the course of opening the assembly, such as might occur with a conventional shielding assembly if a worker adjusts his or her grip on the assembly to twist the base some more when, unbeknownst to the worker, the base has already been twisted far enough to release of the base from the body. Referring to the embodiment shown in FIG. 9, for example, the quick turn connection 191 attaching the base extension element 161 and body 103 may be a “bayonet” type connection. The base extension element 161 may include a plurality of connecting elements 193 (e.g., lugs, threads, or the like) adapted for establishing a connection with a corresponding plurality of connecting elements 195 on the bottom end of the body 103. In one embodiment of the invention, the contact angle “α” (FIG. 10C) between corresponding connecting elements 193, 195 may be selected to provide a secure connection that makes it unlikely that the assembly 101 will be unintentionally opened as it is jostled about during handling and/or that makes it unlikely that the quick connection 191 will jam when someone tries to open the assembly. Referring to FIGS. 10A-10C, for instance, the contact angle “α” between the lugs 193 on the base extension element 161 and the mating lugs 195 on the body 103 may range from a relatively less steep angle that is empirically demonstrated to allow separation of the base 109 from the body without jamming to a relatively steeper angle that is about equal to the arctangent of the coefficient of friction between the mating connecting elements, both of which may vary depending on the materials used to form the connecting elements. As the coefficient of friction decreases, the contact angle “α” may be made less steep. In some embodiments, the coefficient of friction may be between about 0.1 to about 0.2. In other embodiments, the coefficient of friction is between about 0.12 and about 0.15. In still other embodiments, the coefficient of friction is about 0.12. The contact angle “α” may range from about 2 degrees to about 10 degrees in some embodiments. In other embodiments, the contact angle “α” may range from about 5 degrees to about 10 degrees. It is understood that a quick turn threaded connection (e.g., a multi-start threaded connection) between the body 103 and the base 109 can be provided with substantially the same contact angles discussed with reference to the bayonet connection 191 to reduce the risk of unintentional opening of the assembly and to reduce the likelihood of jamming when someone tries to open the assembly 101. Incidentally, some embodiments of the invention may exhibit contact angles and/or coefficients of friction that fall outside of the ranges described above. The quick turn connection 191 shown in FIGS. 9-10C may provide a positive indication when the base 109 has been rotated sufficiently relative to the body 103 to permit opening of the assembly 101 by limiting further rotation of the base when the base is capable of being separated from the body. For example, the lugs 193, 195 may be adapted to function as stops when the base 109 has been rotated far enough to open the assembly 101. Referring to FIGS. 10A-10C, for example, in one embodiment, the generally trapezoidal lugs 193, 195 on the base 109 and body 103 may be sized and spaced so that the lugs on the base may pass between the lugs on the body (FIGS. 10A and 10B). The quick turn connection 191 may be established by rotating the base 109 relative to the body 103 to cause the lugs 193, 195 to engage one another as shown in FIG. 10C. As the base 109 is rotated in the opposite direction to open the assembly 101, the lugs 193, 195 reach a point at which the lugs on the base may pass between the lugs on the body. At that point (FIG. 10B), the lugs 193 on the base 109 abut the lugs 195 on the body 103, thereby limiting the amount of rotation of the base that is possible. When a person opening the assembly 101 feels the lugs 193, 195 contact (e.g., “bump into”) each other, he or she knows that the base 109 can be separated from the body 103 without any additional rotation of the base relative to the body. FIG. 10D shows another embodiment of a quick turn connection 191′ in which the lugs 193′ on the base 109′ include ribs 193a′ extending their taller side. There may be clearance between the lugs 193′, 195′ (except for the ribs 193a′), but the lugs 195′ bump into the ribs 193a′ to provide a positive indication that the assembly 101 can be opened. The base shielding element 163 may be connected (either directly or indirectly as shown in FIG. 3) to the base extension element 161 so that connection of the base extension element to the body 103 interconnects the base shielding element to the body. The base shielding element 163 may be operable to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the second opening 123 when the base extension element 161 is connected to the body 103. As shown in FIG. 3, for example, the base shielding element 163 may include a plug adapted to be slidably received by the second opening 123 of the body 103 into the cavity 117. The base shielding element 163 may be adapted to absorb and/or reflect radiation over an area that is substantially coextensive with the second opening 123, for example, by being configured as a plate having substantially the same shape and size as the opening. In some embodiments of the invention, the base shielding element may be adapted to substantially cover the second opening 123 without being received therein. The base shielding element 163 may include one or more radiation-shielding materials (not shown), as described above. Those skilled in the art will know how to design a base shielding element 163 to include a sufficient amount of one or more radiation-shielding materials to limit escape of radiation from the assembly 101 through the second opening 123 to a desired level. The spacer system 165 may include an adjustable spacer 201, which may be at least partially received in the cavity 117 for selectively configuring the assembly 101 to hold a container selected from a set of containers including containers having different heights (e.g., different volumes). Referring to the embodiment shown in the figures, for example, the spacer 201 may be slidably mounted in the receptacle 203 in the base 109 (e.g., a substantially cylindrical receptacle in the base extension element 161). The receptacle 203 in the base 109 may be adjoin the second opening 123 into the cavity 117 of the body 103 when the base is secured to the body, thereby positioning the spacer 201 for slidable extension into and retraction out of the cavity 117. The base shielding element 163, which may define a support surface for the container C when it is received in the cavity 117, may be secured (e.g., by a threaded connection or other method of attachment) to or integral with the spacer 201. By selective positioning of the spacer 201 with respect to the first opening 121, the position of the base shielding element 163 relative to the first opening 121 of the body 103 can be changed to position the top of each of the containers C at substantially the same location relative to the first opening, notwithstanding their different heights. The spacer 201 can be mounted in the assembly 101 in a variety of different ways. For example, the spacer 201 shown in the figures has a substantially cylindrical surface (e.g., outer surface) having a helical channel 205 defined therein. A detent 209 received in the channel 205 may be another component of the spacer system 165. In some embodiments, like the one shown in the figures, for instance, the detent 209 is associated with (e.g., mounted on) the base extension element 161, but in other embodiments the detent may be associated with other elements of the assembly 101. The detent 209 may be substantially fixed relative to the body 103 (e.g., when it is mounted on the base 109 while it is secured to the body). The detent 209 of the embodiment shown in the figures is a ball detent plunger. The ball detent plunger may be a threaded member 211 having a loosely captured ball 213 therein. A spring (not shown) may be positioned in the threaded member 211 to bias the ball 213 to a position in which a portion of the ball projects outward from an end of the threaded member. The threaded member 211 may be screwed into the base extension element 161 so that the end of the threaded member to which the ball 213 is biased is received in the channel 205. Other detents could be used instead, however. The detent 209 might be characterized as a cam, and the spacer 201 a cylindrical cam follower. The detent 209 engages one side of the helical channel 205 upon rotation of the spacer 201, producing movement (e.g., along an axis 197 of the cavity 117) of the spacer relative to the receptacle 203 in the base extension element 161. Depending on the direction of the rotation, the spacer 201 may be moved out of or into the receptacle 203, corresponding to translation farther into the cavity 117 and out of the cavity in the assembly 101, respectively. Further, as shown in FIGS. 11 and 12, a plurality of recesses 217 adapted to engage the tip of the ball detent plunger 209 may be formed in the bottom of the helical channel 205. Only some of these recesses 217 are shown in the figures. Each of the recesses 217 may be aligned with the ball 213 of the ball detent plunger 200 when the spacer 201 is in one of the positions in which the spacer is adjusted for use with a particular one of the containers in the set. Thus, when the spacer 201 is moved into that position, the tip 213 of the ball detent plunger 209 may engage the respective recess 217 producing an audible click and/or tactile feedback to indicate that the spacer is in position. The recesses 217 may help to hold the spacer 201 in the selected position. Moreover, the spacer 201 may include markings 221 indicating the different heights of the containers positioned on the spacer relative to the helical channel 205 so that when the spacer is positioned for use with one of the containers, the corresponding marking is in a predetermined position in which it is visible while the other markings are obscured from view. In the embodiment shown in the figures, for example, a window 223 is formed in the base 109 below the ball detent plunger 209. Markings 221 are located on the outer surface of the spacer 201 at positions that are offset from (e.g., below) the respective recess 217 an amount corresponding to the amount of offset between the detent 209 and the window 223. When the ball 213 of the ball detent plunger 209 is engaged with one of the recesses 217, the corresponding marking 221 is visible in the window 223. The remaining markings 221 are covered by the base extension element 161 so workers can tell what kind of container is held in the assembly 161 by looking through the window 223 to view the corresponding marking 221, thereby obviating the need to open the assembly 101 to determine or confirm what kind of container is in the assembly. FIGS. 14A-14C and 15A-15C, for example, show a sequence of adjustment of the spacer system 165 for three containers C′, C″, C′″ having three different heights. FIG. 14A shows the spacer 201 positioned for use with a 20 mL container C′ (FIG. 15A), as indicated by the lowered position of the spacer and the marking 221 of “20” on the spacer that is visible in the window 223 through the base extension element 161. By twisting the spacer 201 relative to the base extension element 161 generally about a central longitudinal axis of the base extension element, the spacer can be raised to adapt the assembly to hold a shorter 10 mL container C″ (FIG. 15B). The spacer 201 is shown in this position in FIG. 14B, in which the marking 221 “10” is visible in the window 223 and the spacer has been raised above its position in FIG. 14A. By twisting the spacer 201 even more, the spacer rides farther upward on the ball detent plunger 209 and is thereby raised to adapt the assembly 101 for use with an even shorter 5 mL container C′″ (FIG. 15C). The spacer 201 is shown in this position in FIG. 14C, in which the marking 221 “5” is visible in the window 223 and the spacer has been raised above its position in FIG. 14B. When the spacer 201 is adjusted to the desired position, the base 109 may be connected to the body 103 to enclose a container C in the assembly 101. FIGS. 15A-15C show a 20 mL, 10 mL, and 5 mL container C′, C″, C′″ enclosed in the assembly 101, respectively, with the spacer 201 adjusted accordingly. As shown in FIGS. 15A-15C, the ball detent plunger 209 is engaged with one of the recesses 217 in the helical channel 205 at each of the three positions corresponding to one of the heights of the containers C′, C″, C′″, providing indexed movement of the spacer 201 from a position suitable for use with one of the containers to a position suitable for use with a different one of the containers. It is understood that other constructions for adapting the assembly to work with containers having different heights may be used within the scope of the present invention. Referring to FIG. 16, a second embodiment of a spacer 201′ suitable for use with the assembly 101 shown in FIGS. 1-3, may include a first helical channel 205a′ and a second helical channel 205b′. The first channel 205a′ may be calibrated for use with a first set of containers (e.g., U.S. standard containers) and the second channel 205b′ may be calibrated for use with a second set of containers (e.g., European standard containers). Recesses 217′ and markings 221′ may be provided for each of the channels 205a′, 205b′ in the same way described for the spacer 201 describe previously. This allows the same assembly 101 to be used for indexed movement of the spacer 201′ for various different sets of containers. In order to switch from one set of containers to another, the ball detent plunger 209 is removed from one of the helical channels 205a′, 205b′ (e.g., by partially unscrewing the threaded member 211 to back the detent out of the channel), the spacer 201 is repositioned to align the other helical channel with the detent, and the ball detent plunger is replaced so that it received in the other helical channel. The base 109 of the assembly 101 shown in FIGS. 1-3 may be disconnected from the body 103 to load a container C (e.g., an evacuated elution vial) into the cavity. A worker may adjust the position of the spacer 201 in preparation of the assembly 101 for use with a particular container selected from a set of containers including containers having different heights. As the spacer 201 is moved into position (e.g., by grasping and turning an exposed portion of the spacer and/or base shielding element 163), the ball detent plunger 209 may engage the corresponding recess 217, producing an audible click and/or tactile sensation indicating to the worker that the spacer is in position. The position of the spacer 201 may be confirmed by looking through the window 223 in the base extension element 161 to see which of the markings 221 is visible therein. The container C may be loaded into the cavity 117 through the second opening 123 in the body 103. The collar 107 engages the top of the container C and guides it to the predetermined position in the cavity 117 (e.g., so that the septum at the top of the container is centered under the first opening 121). Then the base 109 may be reconnected to the body 103 to enclose the container C in the cavity 117. The spacer 201, having been adjusted for the height of the container C, holds the container so that its top is adjacent the first opening 121. Those skilled in the art will recognize that it is possible in some embodiments of the invention to adjust the position of the spacer 201 in the cavity 117 after the base 109 is connected to the assembly 101 without departing from the scope of the invention. The cap 105 may be removed for an elution process. For example, after the cap 205 is removed (FIG. 5), the container C may be connected to a radioisotope generator by piercing the septum of the container C with a needle in fluid communication with the generator using the first opening 121 for access to the container. Then the eluate may flow into the container C through the needle (e.g., using a vacuum pressure in the container to draw the eluate out of the generator). The needle may be removed from the container C when the container has received a desired volume of eluate. The cap 105 may be releasably attached to the body 103 to limit escape of radiation emitted by the eluate from the assembly 101 through the first opening 121. Because the cap 105 is held onto the body 103 (e.g., by magnetic attraction between the cap and body) the cap is less likely to be accidentally knocked off the body. The container C may be carried to another location, such as a calibration station, while in the assembly with the cap releasably attached to the body 103 in the first orientation. When the eluate is ready to be dispensed into other containers (e.g., syringes or other types of containers used for subsequent processing of the eluate), the cap 105 may be removed from the body 103 and placed bottom side down on a work surface. The then body 103 and base 109 of the assembly 101 may be inverted and placed on the cap 105 as shown in FIG. 6, for example. The cap 105 engages the body 103 and limits escape of radiation emitted by the eluate. When a worker is ready to transfer some of the eluate from the container C in the assembly to a different container, he or she may simply lift the body 103 and base 109 off the cap 105 to access the container through the first opening 121. For example, the body 103 and base 109 may be lifted off the cap 105 with a single hand (as shown in FIG. 7) and held with that hand while the eluate is transferred to the other container (e.g., by piercing the septum of the container C with the tip of a needle attached to a syringe and drawing the eluate into the syringe). After a desired amount of eluate has been withdrawn from the container C in the assembly 101, the body 103 and base 109 can be replaced on the cap 105 until more eluate is needed from the container. When the container C is empty or when the eluate in the container is no longer needed, the base 109 may be rotated relative to the body 103 to open the assembly 101. A worker may manually rotate the base 109 relative to the body 103. Because of the quick turn connection 191, the worker is able to release the base 109 from the body 103 by turning the base no more than about 180 degrees, which may be accomplished without requiring the worker to release his or her grip on the body or base to rotate the base farther. In one embodiment, the base 109 may be released from the body 103 by turning the base no more than about 90 degrees. In another embodiment, the base may be released from the body by turning the base no more than about 45 degrees. Moreover, when the base 109 has been rotated a sufficient amount to release the base from the body 103, the worker receives a positive indication (e.g., a tactile sensation such as an inability to rotate the base farther) that no additional turning of the base is required to separate the base from the body. This alerts the worker to the need to keep a firm grip on the base 109 and the body 103, thereby reducing the risk that the base will accidentally separate from the body and possibly let the container C fall out of the assembly 101. When the base 109 is separated from the body 103, the container C can be removed from the cavity 117. Then another evacuated container C may be selected and the process repeated. If the new container has a different height than the previous container, the spacer 201 may be adjusted accordingly. FIGS. 19 and 20 illustrate another embodiment of a radiation shielding assembly, generally designated 501, of the present invention. Except as noted, the illustrated assembly 501 is constructed and operates the same as the assembly 101 described above. Both assemblies 501, 101 include the same body 103, cap 105, base shielding element 163, and spacer system 165. The base 509 of the assembly 501 is similar in overall shape and function to the base 109 described above. One difference is that the base 509 comprises a radiation shielding element 521 and a non-shielding element 523. The shielding element 521 may be constructed of a relatively dense radiation shielding material (e.g., a moldable tungsten impregnated plastic material) while the non-shielding element 523 may be constructed of one or more relatively inexpensive, lightweight, durable materials, such as high impact polycarbonate materials (e.g., Lexan®), nylon, and the like. The non-shielding element 523 may surround at least a portion of the shielding element 521. For example, the shielding element 521 shown in the figures has a generally tubular portion 529. A moldable plastic material may be molded over the shielding element 521 to form the non-shielding element. One end 531 of the shielding element 521 may extend from the non-shielding element and be adapted to releasably secure the base 509 to the body 103 in substantially the same manner as the base 109 of the assembly 101 described above. As shown in FIGS. 19 and 20, the tubular portion 529 of the shielding element may transition from a relatively thicker portion 535 at the end that is closer to the body 103 when the base is releasably secured to the body to a relatively thinner portion 537 at the opposite end. Moreover, the non-shielding element 523 may extend farther away from the body 103 than the shielding element 521 when the base 509 is releasably secured to the body. Consequently, the radiation shielding provided by the base 509 may concentrated in the part of the base that is adjacent the radioactive material in the container C. Further, the center of gravity of the assembly 501 is shifted toward the end of the assembly opposite the base (compared to where it would be if the entire base were made of radiation shielding material), thereby increasing stability of the assembly when it is placed on a support surface (e.g., in a manner analogous to the way the assembly 101 described above is oriented in FIGS. 6 and 6A). The non-shielding element 523 may have an internal surface defining a plurality of inwardly extending ridges 525. The shielding element 521 may have an external surface defining a plurality of outwardly extending ridges 527 such that the inwardly extending ridges 525 of the non-shielding element engage grooves 547 defined by the outwardly extending ridges and the outwardly extending ridges 527 engage grooves 545 defined by the inwardly extending ridges. The non-shielding element may be fixed to the shielding element by engagement of the grooves and ridges. One advantage of forming the non-shielding element 523 in an overmolding process is that the inwardly extending ridges 525 thereof may be formed in situ relative to the grooves defined by the outwardly extending ridges of the shielding element. It is understood that the base 509 shown in FIGS. 19 and 20 may be used with radiation shielding assemblies having configurations other than shown herein without departing from the scope of the present invention. Another embodiment of the invention is depicted in FIGS. 21-23C as a dual-purpose front loaded radiation shielding assembly, generally designated 301, which is suitable for use as elution and/or dispensing shield. As best seen in FIG. 22, the assembly includes a cap 305, a body 303 at least partially defining a cavity 317, a spacer 365, and a base 309. The assembly 301 is generally similar in construction and operation to the assembly 101 described above. The body 303 may be a two-part body including a main body 311 and a lid 313. The main body 311 may be a generally tubular structure having an open top end 333 defining an opening 323 (FIG. 22) sized to permit a container C to pass therethrough for loading and unloading of containers to and from the cavity 317 and a closed bottom end 363 adapted to limit escape of radiation emitted in the cavity 317 from the assembly 301 through the bottom of the body 303. The lid 313 is adapted to be received in the opening 323 of the main body 311. Moreover, the lid 313 defines an opening 321 that may be similar to the first opening 121 of the assembly 101 described above. The cap 305 may be similar in construction and operation to the cap 105 of the assembly 101 discussed above. The spacer 365 shown in FIGS. 22-23C may be a cylindrical sleeve having a perpendicular cross support 367 spanning the inner diameter of the spacer. The spacer 368 may be positioned as shown in 23A for use with a relatively shorter container C′″. To adapt the assembly 301 for use with a taller container C″, the spacer 365 may be inverted as shown in FIG. 23B. To adapt the assembly 301 for use with an even taller container C′ the spacer 365 may be removed from the cavity. The bottom of the main body 311 may be adapted for connection (e.g., a threaded connection) to the base 309. The base of the embodiment shown in the figures may be similar in construction to the lightweight base extension element described above. The spacer system 165 described above is not used in this embodiment and the base shielding element 163 may be omitted because it would be redundant with the closed bottom end 363 of the main body 311. The base 309 defines a stowage receptacle 385 sized and shaped for storing the spacer 365 when it is not in the cavity 317. The base 309 and/or spacer 365 may be adapted to releasably secure the spacer within the stowage receptacle 385 to prevent the spacer from falling out of the stowage receptacle. For example, the base 309 may include detents 387 (FIGS. 23A-23C and 24) adapted to engage recesses 389 in the spacer to establish a snap connection between the spacer 365 and the base 309. Other fasteners could be used instead without departing from the scope of the invention. Use of the assembly 301 is generally similar to use of the assembly 101 described above. One difference in use is the manner in which containers C are loaded into and taken out of the cavity 317. The assembly 301 can be used for elution and dispensing just like the assembly 101 described previously. The spacer 365 may be adjusted for a particular container selected from a set of containers C′, C″, C′″ having different heights. When the spacer 365 is not used (e.g., when the tallest container C′ of the set is being held in the cavity 317) the spacer may be stowed in the stowage receptacle 385 in the bottom of the base 309, as shown in FIGS. 23C and 25. For example, the stowage receptacle 385 may be sized and shaped to permit the spacer 365 to be inserted into the stowage receptacle so that the spacer is in close fitting relationship with the sides of the receptacle. By inserting the spacer 365 into the receptacle 385, the user may engage a snap fit (as shown in the figures), a friction fit, or another suitable means of securing the spacer in the receptacle. The user may secure the spacer 365 in the receptacle 385 after it is already in the receptacle (e.g. by using a separate fastener, for example) without departing from the scope of the invention. Those skilled in the art will recognize that the radiation-shielding assemblies 101, 301 described above can be modified in many ways without departing from the scope of the invention. For example, the cap may be a non-reversible cap releasably attached to the body by a bayonet connection, a threaded connection, a snap connection or other suitable releasable fastening system without departing from the scope of the invention. The collar may be omitted if desired. The assembly can be modified to accommodate virtually any style of container. Likewise, the assembly can be modified for use with other styles of radioisotope generators. An assembly may be used only for elution or only for dispensing without departing from the scope of the invention. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. When introducing elements of the present invention or the illustrated embodiments thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” and variations of these terms are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of “top” and “bottom” and variations of these terms is made for convenience, but does not require any particular orientation of the components. As various changes could be made in the above assemblies and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying figures shall be interpreted as illustrative and not in a limiting sense.
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	abstract	The present invention relates to a specimen box for an electron microscope, comprising a first substrate, a second substrate, one or more photoelectric elements, and a metal adhesion layer. The first substrate has a first surface, a second surface, a first concave, and one or more first through holes, wherein the first through holes penetrate through the first substrate. The second substrate has a third surface, a forth surface, and a second concave. The photoelectric element is disposed between the first substrate and the second substrate. In addition, the metal adhesion layer is disposed between the first substrate and the second substrate to form a space for a specimen contained therein. Besides, the present specimen box further comprises one or more plugs. When the plugs are assembled into the first through holes to seal the specimen box, the in-situ observation can be accomplished by using the electron microscope.
052767191	abstract	A hydraulic control rod drive for a nuclear reactor, with a a reactor plenum enclosing the drive, comprises first and second hollow bodies together forming a cylinder and a hollow piston. Working fluid is supplied through one of the hollow bodies. The first hollow body is stationary and the second hollow body is disposed coaxially around the first hollow body. The two hollow bodies define an annular gap therebetween so as to allow axial reciprocating movement of the second hollow body, which forms a carrier body for control elements of the control rod. The second hollow body can be lifted, lowered or suspended by feeding working fluid. A portion of the fluid is removed from the inner space via a throttle passage. A positional measurement system determines the relative displacement of the second hollow body by measuring an ultrasonic measurement path. The system includes an ultrasound reflector and an ultrasonic transducer rigidly mounted remote from the ultrasound reflector. Provisions are made for venting the inner space through venting channels which open into the reactor plenum at a security distance from the measurement path so as not to adversely affect the ultrasonic measurement.
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	abstract	A nuclear steam supply system utilizing gravity-driven natural circulation for primary coolant flow through a fluidly interconnected reactor vessel and a steam generating vessel. In one embodiment, the steam generating vessel includes a plurality of vertically stacked heat exchangers operable to convert a secondary coolant from a saturated liquid to superheated steam by utilizing heat gained by the primary coolant from a nuclear fuel core in the reactor vessel. The secondary coolant, may be working fluid associated with a Rankine power cycle turbine-generator set in some embodiments. The steam generating vessel and reactor vessel may each be comprised of vertically elongated shells, which in one embodiment are arranged in lateral adjacent relationship. In one embodiment, the reactor vessel and steam generating vessel are physically discrete self-supporting structures which may be physically located in the same containment vessel.
	claims	1. A charged particle beam apparatus comprising:a charged particle source;a deflector for scanning a charged particle beam emitted from said charged particle source; anda detector for detecting secondary signals emitted from a scanned region of said charged particle beam, a sample image being formed based on said secondary signals detected by said detector, which further comprises:a control unit for forming a plurality of images based on said detected secondary signals, sharpening said formed images, detecting positional displacement between said sharpened images, and superposing images so as to correct the detected positional displacement. 2. A charged particle beam apparatus according to claim 1, wherein said plurality of images are formed by a unit of two-dimensional scanning performed by said deflector. 3. A charged particle beam apparatus according to claim 1, wherein said plurality of images are acquired in different timing. 4. A charged particle beam apparatus according to claim 1, wherein an image shift deflector for shifting a scanning region of said charged particle beam and a sample stage for moving a sample are provided, wherein said control unit detects directions of positional displacements among said sharpened images, and operates said image shift deflector and said sample stage so that said scanning region is positioned toward directions canceling said positional displacements. 5. A charged particle beam apparatus according to claim 1, wherein said control unit shifts said scanning region using said image shift deflector and said sample stage when an amount of said positional displacement is larger than a preset value, and shifts said scanning region using said image shift deflector when an amount of said positional displacement is smaller than a preset value. 6. A charged particle beam apparatus comprising:a charged particle source;a deflector for scanning a charged particle beam emitted from said charged particle source; anda detector for detecting secondary signals emitted from a scanned region of said charged particle beam, a sample image being formed based on said secondary signals detected by said detector, which further comprises:a control unit for forming a plurality of images on the basis of said detected secondary signals and forming composite images of said formed images, wherein number of pixels of said formed images before being superimposed is larger than number of pixels of said composite images. 7. A charged particle beam apparatus according to claim 6, wherein said plurality of images are formed by a unit of two-dimensional scanning performed by said deflector. 8. A charged particle beam apparatus according to claim 6, wherein said plurality of images are acquired in different timing. 9. A charged particle beam apparatus according to claim 6, wherein an image shift deflector for shifting a scanning region of said charged particle beam and a sample stage for moving a sample are provided, wherein said control unit detects directions of positional displacements among said composite images, and operates said image shift deflector and said sample stage so that said scanning region is positioned toward directions canceling said positional displacements. 10. A charged particle beam apparatus according to claim 6, wherein said control unit shifts said scanning region using said image shift deflector and said sample stage when an amount of said positional displacement is larger than a preset value, and shifts said scanning region using said image shift deflector when an amount of said positional displacement is smaller than a preset value.
	description	FIG. 1 is a schematic of a containment building 36 that houses a reactor pressure vessel 42 with various configurations of fuel 41 and reactor internals for producing nuclear power in a related art economic simplified boiling water reactor (ESBWR). Reactor 42 is conventionally capable of producing and approved to produce several thousand megawatts of thermal energy through nuclear fission. Reactor 42 sits in a drywell 51, including upper drywell 54 and a lower drywell 3 that provides space surrounding and under reactor 42 for external components and personnel. Reactor 42 is typically several dozen meters high, and containment building 36 even higher above ground elevation, to facilitate natural circulation cooling and construction from ground level. A sacrificial melt layer 1, called a basemat-internal melt arrest and coolability device, is positioned directly below reactor 1 to cool potential falling debris, melted reactor structures, and/or coolant and prevent their progression into a ground below containment 36. Several different pools and flowpaths constitute an emergency core coolant system inside containment 36 to provide fluid coolant to reactor 26 in the case of a transient involving loss of cooling capacity in the plant. For example, containment 36 may include a pressure suppression chamber 58 surrounding reactor 42 in an annular or other fashion and holding suppression pool 59. Suppression pool 59 may include an emergency steam vent used to divert steam from a main steam line into suppression pool 59 for condensation and heat sinking, to prevent over-heating and over-pressurization of containment 36. Suppression pool 59 may also include flow paths that allow fluid flowing into drywell 54 to drain, or be pumped, into suppression pool 59. Suppression pool 59 may further include other heat-exchangers or drains configured to remove heat or pressure from containment 36 following a loss of coolant accident. An emergency core cooling system line and pump 10 may inject coolant from suppression pool 59 into reactor 42 in order to make up lost feedwater and/or other emergency coolant supply. As shown in FIG. 1, a gravity-driven cooling system (GDCS) pool 37 can further provide coolant to reactor 42 via piping 57. A passive containment cooling system (PCCS) pool 65 may condense any steam inside containment 36, such as steam created through reactor depressurization to lower containment pressure or a main steam line break, and feed the condensed fluid back into GDCS pool 37. An isolation cooling system (ICS) pool 66 may take steam directly at pressure from reactor 42 and condense the same for recirculation back into reactor 42. These safety systems may be used in any combination in various reactor designs, each to the effect of preventing overheating and damage of core 41, reactor 42 and all other structures within containment 36 by supplying necessary coolant, removing heat, and/or reducing pressure. Several additional systems are typically present inside containment 36, and several other auxiliary systems are used in related art ESBWR. Such ESBWRs are described in “The ESBWR Plant General Description” by GE Hitachi Nuclear Energy, Jun. 1, 2011, incorporated herein by reference in its entirety, hereinafter referred to as “ESBWR.” Example embodiments include nuclear reactors having virtually no failure mode outside of their containment. Example embodiment nuclear reactors may be similar to ESBWR designs with larger height-to-width ratios that enable natural circulation within the pressure vessel, but smaller, especially in the width direction, to produce less than 1000 megawatts thermal energy. Example embodiment containments may fully surround the nuclear reactor and prevent fluid leakage out of the containment even at elevated pressures. Example embodiment containments may be extremely simplified with no coolant sources like GDCS pools, suppression pools, or moving coolant pumps. One of more coolant sources outside containment, like isolation condenser systems, are sufficient to provide long-term, reliable cooling to the nuclear reactor. Example embodiment isolation valves can be used at each fluid connection to the reactor to make the reactor integrally isolatable, including for the primary coolant loop and the emergency coolant source. Example-embodiment isolation valves are redundant and integral with the nuclear reactor and fluid conduit and fabricated up to ASME nuclear standards for reactor vessels so as to eliminate risk of shear failure. Where example embodiment containment is penetrated, penetration seals may surround and make impermeable containment at the penetrations to high gauge pressures. Example embodiment containments and reactors may be completely underground and, along with an emergency coolant source, surrounded by a seismic silo that shields the same from earthquake and other shocks. Limited access pointed, such as a single top shield covering the silo and containment, may provide simplified access for maintenance, flooding, and/or refueling. Because this is a patent document, general, broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only examples set forth herein. It will be understood that, although the ordinal terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited to any order by these terms. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments or methods. As used herein, the term “and/or” includes all combinations of one or more of the associated listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s). It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” “fixed,” etc. to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange and routing between two electronic devices, including intermediary devices, networks, etc., connected wirelessly or not. As used herein, the singular forms “a,” “an,” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof. The structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from single operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments. The inventors have recognized that ESBWRs have large 1000+ megawatt-electric power ratings with associated large reactor volumes and construction costs. The inventors have further recognized that the large sizes of ESBWRs generally require large containments that can feasibly be constructed only above ground. ESBWRs also use numerous passive safety systems with piping conduits and other flowpaths to the reactor capable of breaking or leaking, causing a loss of coolant accident. The inventors have further recognized that ESBWRs are useable primarily for long-term, baseline power generation, without modularity or flexibility of construction and operation in areas needing immediate or peaking power generation capacity. To overcome these newly-recognized problems as well as others, the inventors have developed example embodiments and methods described below to address these and other problems recognized by the inventors with unique solutions enabled by example embodiments. The present invention is nuclear reactors, plants containing the same, and methods of operating such reactors and plants. In contrast to the present invention, the few example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. FIG. 2 is a schematic of an example embodiment reactor system 100 including example embodiment reactor 142, example embodiment containment 136, and related cooling and power generation systems. Although not shown in FIG. 2, example embodiment system 100 is useable with conventional and known power generating equipment such as high- and low-pressure turbines, electrical generators, switchyards, condensers, cooling towers or heat sinks, etc., which may connect, for example to main feedwater line 120 and main steam line 125 in a similar fashion to any power generation facility. Example embodiment containment 136 is composed of resilient, impermeable material for limiting migration of radioactive material and plant components in the case of a transient or accident scenario. For example, containment 136 may be an integrally-formed concrete structure, potentially with reinforcing internal steel or rebar skeleton, several inches or feet thick. Or, for example, as discussed below, because containment 136 may be relatively smaller, an all-steel body may be use without being prohibitively expensive or complexly-fabricated, to enhance strength, radiation shielding, and lifespan of containment 136. As shown in FIG. 2, example embodiment containment 136 may be underground, potentially housed in a reactor silo 190. A concrete lid 191 or other surface shield level with, or below, ground 90 may enclose silo 190 housing example embodiment reactor 142 and containment 136. Silo 190 and lid 191 may be seismically isolated or hardened so as to minimize any shock wave encountered from the ground and thus minimize impact of seismic events on reactor 142. If underground as shown in FIG. 2, example embodiment system 100 may present an exceedingly small strike target and/or be hardened against surface impacts and explosions. Further, if underground, example embodiment system 100 may have additional containment against radioactive release and enable easier flooding in the case of emergency cooling. Although not shown, any electricity-generating equipment may be connected above ground without loss of these benefits, and/or such equipment may also be place below ground. Based on the smaller size of example embodiment reactor 142 discussed below, example embodiment containment 136 may be compact and simplified relative to existing nuclear power plants, including the ESBWR. Conventional operating and emergency equipment, including a GDCS, PCCS, suppression pools, Bimacs, backup batteries, wetwells, torii, etc. may be wholly omitted from containment 136. Containment 136 may be accessible through fewer access points as well, such as a single top access point under shield 191 that permits access to reactor 142 for refueling and maintenance. The relatively small volume of example embodiment reactor 142 and core 141 may not require a bimac for floor arrest and cooling, because no realistic scenario exists for fuel relocation into containment 136; nonetheless, example embodiment containment 136 may have sufficient floor thickness and spread area to accommodate and cool any relocated core in its entirety, as shown in FIG. 2. Moreover, total penetrations through containment 136 may be minimized and or isolated, as discussed further in connection with FIG. 3, below, to reduce or effectively eliminate risk of leakage from containment 136. Example embodiment reactor 142 may be a boiling-water type reactor, similar to approved ESBWR designs in reactor internals and height. Reactor 142 may be smaller than, such as one-fifth the volume of, ESBWRs, producing only up to 600 megawatts of electricity for example, with a proportionally smaller core 141, for example operating at less than 1000 megawatt-electric. For example, example embodiment reactor 142 may be almost 28 meters in height and slightly over 3 meters in diameter, with internals matching ESBWR internals but scaled down proportionally in the transverse direction to operate at approximately 900 megawatt-thermal and 300 megawatt-electric ratings. Or, for example, reactor 142 may be a same proportion as an ESBWR, with an approximate 3.9 height-to-width ratio, scaled down to a smaller volume. Of course, other dimensions are useable with example embodiment reactor 142, with smaller height-to-width ratios such as 2.7, or 2.0, that may enable natural circulation at smaller sizes or proper flow path configuration inside the reactor. Keeping a relatively larger height of example embodiment reactor 142 may preserve natural circulation effects achieved by known ESBWRs in example embodiment reactor 142. Similarly, smaller reactor 142 may more easily be positioned underground with associated cooling equipment and/or possess less overheating and damage risk due to smaller fuel inventory in core 141. Even further, smaller example embodiment reactor 142 with lower power rating may more readily satisfy modular power or peaking power demands, with easier startup, shutdown, and/or reduced power operations to better match energy demand. A coolant loop, such as main feedwater line 120 and main steam line 125, may flow into reactor 142 in order to provide moderator, coolant, and/or heat transfer fluid for electricity generation. An emergency coolant source, such as one or more isolation condenser systems 166, may further provide emergency cooling to reactor 142 in the instance of loss of feedwater from line 120. Each isolation condenser system 166 may further have two connections to example embodiment reactor 142, one for steam outlet and one for condensate return to reactor 142. Each of these connections to reactor 142 may use isolation valves 111, 112, 167, and/or 168 that are integrally connected to reactor 142 inside containment 136 and represent negligible failure risk. When using isolation valves 111, 112, 167, and/18 168 with a small number of systems flowing into example embodiment reactor 142, the possibility of a loss of coolant accident is negligible, at least several orders of magnitude less than the risk in conventional light water plants. FIG. 3 is a schematic of an example embodiment isolation valve 200, which may be used for any of valves 111, 112, 167, and/or 168, or any other valve for fluid delivery to/removal from example embodiment reactor 142 through example embodiment containment 136. Although valves 111, 112, 167, and 168 are shown straddling containment 136 in FIG. 2, it is understood that they may also be completely inside containment 136 as shown in FIG. 3. Example embodiment valve body 201, including two isolation gate valves 210 and 220 and connections between the two, has high-reliability operation without any comparable risk of leakage or failure. For example, valve 200 is not susceptible to guillotine-type shear breaks found in conventional steam and feedwater lines inside containment of ESBWRs. If used with a smaller-size example embodiment reactor 142, valve 200 may be smaller and/or simplified and control relatively less feedwater or steam flows than conventional conduits and valves, further reducing fabrication challenges and risk of failure in example embodiment system 100 (FIG. 2). As shown in FIG. 3, valve 200 includes a primary isolation gate valve 210 and a secondary isolation gate valve 220 for redundant sealing and/or blowout prevention. Primary and secondary gate valves 210 and 220 are integrally formed with valve body 201 that connects to reactor 142 and a flow conduit, permitting flow therebetween with no risk of breakage or disconnect. Higher-reliability actuators 211 and 212 may each be respectively connected to primary and secondary gate valves 210 and 220 and allow minimal leakage from gate valves 210 and 220. Primary isolation gate valve 210 and actuator 211 may be a CCI high-energy isolation gate valve and actuator disclosed in “CCI Nuclear Valve Resource Guide for Power Uprate and Productivity Gains,” 2003, CCI, incorporated herein by reference in its entirety, for example. Secondary isolation gate valve 220 and actuator 212 may be another CCI high-energy isolation gate valve and actuator. Similarly, valves 210 and 220 may be check valves, globe valves, etc. having high reliability and no significant shear breakage failure mode when formed together in valve body 201. Valve body 201 may be made of a single piece of forged material, such as a metal useable in an operating nuclear reactor environment, including all of primary isolation gate valve 210 and secondary isolation gate valve 220 as a single piece. Alternatively, ASME-standard welding, such as between primary and secondary valves 210 and 220, may be used at reactor vessel-level of reliability. Valve body 201 is further integrally welded to reactor 142 using ASME-standard welding with negligible failure possibility. In this way, all flow paths or conduits may be integral with reactor 142 inside containment 136, where “integral” is defined throughout this disclosure as “with material continuity and inseparability, including single-piece forged and welded materials at ASME nuclear specifications.” Because example embodiment valve 200 as integrally joined to reactor 142 and cannot realistically break, possibility of an un-isolatable loss of coolant accident from reactor 142 is effectively eliminated. In this way, reactor 142 is integrally isolatable from any external conduit (such as feedwater line 120 or main steam line 125 in FIG. 2) to which valve body may join in any manner. Where valve body 201 passes through containment 136, a penetration seal 102 may be used to isolate and impermeably seal about valve body 201. Penetration seal 102 may maintain a large pressure gradient across containment 136 without passage of material about valve 200. With the smaller failure risk of example embodiment valve 200 and added isolation of penetration seals 102, there may be relatively low risk of a loss of coolant or leakage into or from containment 136, because any breakage must occur in a conduit outside containment. That is, containment seal 102 at an end valve body 201 effectively eliminates the risk of any pipe break injecting coolant into containment 140 from the balance of plant piping inventory. Alternatively, penetration seal 102 may be positioned on a conduit joining to valve body 201, at a very short distance inside containment 136. As seen in FIG. 2, all of valves 111, 112, 167, 168 and any other fluid connections to reactor 142 may use example embodiment valve 200 of FIG. 3 to eliminate any non-negligible risk of flow path failure inside containment 136. Valves 112, 111, 168, and/or 167 may be passively actuated into fail-safe configurations. For example, main feedwater valve 111 and/or main steam valve 112 may be sealed closed in the event of an accident or abnormal operating condition. Battery-operated, explosive, and/or fail-closed solenoid actuators of the valves, for example, may be initiated upon detecting abnormal operating conditions. At the same time, isolation condenser valves 167 and 168 may be opened with similar reliability, allowing passive heat removal from reactor 142 through isolation condenser system 166. Isolation condensers 166 may be known designs that transfer reactor heat to ambient environment and condense reactor coolant without leakage. Similarly, isolation condensers 166 may be condensers 300 from co-owned application Ser. No. 15/635,400 to Hunt, Dahlgren, and Marquino, filed Jun. 28, 2017 for ISOLATION CONDENSER SYSTEMS FOR NUCLEAR REACTOR COMMERCIAL ELECTRICITY GENERATION and incorporated by reference herein in its entirety. The relatively lower power of example embodiment reactor 142 may permit safe cooling through simple, passive operation of isolation condenser 166 for several days without operator intervention without risk of overheating, loss of coolant, or other damage to reactor 142. Aside from valves 111, 112, 167, and 168, example embodiment containment 136 may be sealed about any other valve or penetration, such as power systems, instrumentation, coolant cleanup lines, etc. The fewer penetrations, smaller size, lack of systems inside, and/or underground placement of containment 136 may permit a higher operating pressure, potentially up to near reactor pressures of several hundred, such as 300, psig without any leakage potential. As seen in example embodiment reactor system 100, several different features permit significantly decreased loss of coolant probability, enable responsive and flexible power generation, reduce plant footprint and above-ground strike target, and/or simplify nuclear plant construction and operation. Especially by using known and approved ESBWR design elements with smaller volumes and core sizes, example embodiment reactor 142 may still benefit from passive safety features such as natural circulation inherent in the ESBWR design, while allowing a significantly smaller and simplified example embodiment containment 136 and reliance on passive isolation condensers 166 for emergency heat removal. Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, a variety of different coolants and fuel types are compatible with example embodiments and methods simply through proper operating and fueling of example embodiments—and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.
062947893	abstract	A radiation intensifying screen is formed by a reflective-transmissive layer which is disposed between two radiation absorbing, luminescent phosphor layers having emission maximum wavelengths which are well separated. The reflective-transmissive layer is either a long wave pass or short wave pass filter which provides maximum reflection for spectral emissions produced in the first luminescent layer but, at the same time, allows the maximum transmission of spectral emissions produced in the second luminescent layer. An optional secondary reflective layer and a backing layer are provided adjacent to the second luminescent layer. As a result, spectral emissions in the first luminescent layer have a relatively short traveling path compared to the path in a conventional intensifying screen. The disclosed dual layer intensifying screen construction increases the spatial resolution of the phosphor screen without adversely affecting the screen speed.
	summary
055368964	claims	1. A method for the processing of solid organic sulphur-containing waste from nuclear facilities comprising: (a) subjecting said waste to pyrolysis at a temperature of no more than 700.degree. C. to form a gas which contains organic sulphur compounds, and a solid pyrolysis residue which contains radioactive material from the waste, (b) separating said gas from the pyrolysis residue and pyrolyzing or cracking said gas following separation to break down the organic sulphur compounds in the gas to carbonaceous compounds having a lower number of carbon atoms and inorganic sulphur compounds, and (c) contacting said gas following its separation and pyrolysis to a bed of a sulphide-forming metal under conditions in which the sulphur compounds present therein form metal sulphides of said metal. (a) a pyrolysis reactor for carrying out pyrolysis on the solid waste, (b) a pyrolysis or cracking reactor to break down the organic sulphur compounds in the gas emanating from reactor (a), and (c) a bed of a sulphide-forming metal for the formation of metal sulphide with the gas from said pyrolysis or cracking reactor (b). 2. A method according to claim 1 comprising subjecting said gas of step (a) to condensation conditions wherein tar products present therein condense out and are separated prior to step (b). 3. A method according to claim 1, wherein following step (a) any fly ash present in said waste is separated from said gas. 4. A method according to claim 1, wherein the pyrolysis of step (a) is carried out at a temperature in the range of 400.degree.-700.degree. C. 5. A method according to claim 1 wherein the pyrolysis of step (a) is carried out in the absence of a catalyst for the breaking down of carbon compounds that are present in the waste. 6. A method according to claim 1, wherein the pyrolysis of step (a) is carried out in a gravity reactor or a flash reactor. 7. A method according to claim 1, wherein the pyrolyzing or cracking of step (b) is carried out in the absence of a cracking catalyst and at a higher temperature than the pyrolysis of step (a). 8. A method according to claim 1, wherein the pyrolysis or cracking of step (b) is carried out in the presence of a cracking catalyst and at a temperature above 600.degree. C. 9. A method according to claim 8, wherein the pyrolysis or cracking of step (b) is carried out in the presence of dolomite lime. 10. A method according to claim 1, wherein step (c) is performed at a temperature in the range of 400.degree.-600.degree. C. 11. A method according to claim 1, wherein the volume of said residue resulting from step (a) is reduced by compression. 12. A method according to claim 1, wherein said steps are carried out at a negative pressure. 13. A method according to claim 1, wherein following step (b) said gas is subjected to filtration. 14. A method according to claim 1, wherein following step (c) exhaust gas is subjected to oxidation. 15. Apparatus for the processing of solid organic sulphur-containing waste from nuclear facilities comprising: 16. Apparatus according to claim 15, wherein pyrolysis reactor (a) is a gravity or flash reactor. 17. Apparatus according to claim 15, which includes prior to reactor (b) a condenser for the condensation of tar products present in the gas. 18. Apparatus according to claim 15, wherein a filter is provided in reactor (a) for the separation of any fly ash from the gas. 19. Apparatus according to claim 15, wherein a filter is provided for the separation of soot from the gas exiting from reactor (b). 20. Apparatus according to claim 15, wherein a compactor is provided for the compression of pyrolysis residue resulting from reactor (a). 21. Apparatus according to claim 15, wherein an afterburner is provided after bed (c). 22. A method according to claim 2, wherein after step (a) any fly ash is separated from the gas. 23. Apparatus according to claim 16, wherein prior to reactor (b) a condenser is provided for the condensation of coal tar products in the gas. 24. A method according to claim 1, wherein said solid organic sulphur-containing waste is an ion exchange medium and said method reduces the volume of said waste. 25. A method according to claim 1 wherein said pyrolysis of step (a) is carried out at a temperature of no more than 600.degree. C. 26. A method according to claim 1 wherein said pyrolysis of step (a) is carried out at a temperature in the range of 400.degree. to 600.degree. C. 27. A method according to claim 1 wherein said pyrolysis step (a) is carried out at a temperature in the range of 450.degree. to 550.degree. C. 28. A method according to claim 1 wherein following step (b) and prior to step (c) the gas resulting from step (b) is subjected to reducing conditions wherein any sulphur oxides that are present are reduced to hydrogen sulphide. 29. A method according to claim 6 wherein said pyrolysis of step (a) is carried out for a residence time of less than 10 seconds. 30. A method according to claim 6 wherein said pyrolysis of step (a) is carried out for a residence time of 5 to 8 seconds. 31. A method according to claim 7 wherein said pyrolyzing or cracking of step (b) is carried out at a temperature above 700.degree. C. 32. A method according to claim 7 wherein said pyrolyzing or cracking at step (b) is carried out at a temperature in the range above 700.degree. C. to 1300.degree. C. 33. A method according to claim 7 wherein said pyrolyzing or cracking of step (b) is carried out at a temperature in the range above 700.degree. C. to 1000.degree. C. 34. A method according to claim 7 wherein said pyrolyzing or cracking of step (b) is carried out at a temperature in the range above 700.degree. C. to 850.degree. C. 35. A method according to claim 8 wherein said pyrolyzing or cracking of step (b) is carried out at a temperature in the range of above 600.degree. C. to 1300.degree. C. 36. A method according to claim 8 wherein said pyrolyzing or cracking of step (b) is carried out at a temperature in the range of 650.degree. C. to 1300.degree. C. 37. A method according to claim 28 wherein said reducing conditions are carried out at a temperature in the range of 700.degree. C. to 900.degree. C. 38. A method according to claim 28 wherein said reducing conditions are carried out at a temperature of approximately 800.degree. C. 39. A method according to claim 1 wherein step (c) is performed at a temperature of approximately 500.degree. C. 40. A method according to claim 13 wherein said filtration is performed with the use of a carbon filter. 41. Apparatus according to claim 15 wherein a bed of solid reductant for the reduction of any sulphur dioxide gas present in gas that leaves pyrolysis or cracking reactor (b) is situated intermediate pyrolysis or cracking reactor (b) and bed (c). 42. Apparatus according to claim 18 wherein said filter is a ceramic filter. 43. Apparatus according to claim 19 wherein said filter is a carbon filter.
	abstract	An embodiment of the present invention takes the form of an apparatus or system that may reduce the level of vibration experienced by an inlet riser or other similar object within a reactor pressure vessel. An embodiment of the present invention may eliminate the need for welding the riser brace to the inlet riser. An embodiment of the present invention provides at least one riser brace clamp that generally clamps the riser brace to the inlet riser. After installation, the riser brace clamp may lower the amplitude of, and/or change the frequency of, the vibration experienced by the inlet riser.
055901689	claims	1. In an X-ray microscope in which a specimen is irradiated with X-rays having a wave length region of 65 to 43.7.ANG. and ultraviolet rays and X-rays transmitted through the specimen are received by an X-ray detector to form a transmitted X-ray microscopic image of the specimen, the improvement being characterized in that a ultraviolet transmissive window is provided in a wall of a vacuum chamber in which an X-ray optical system of the X-ray microscope is arranged and the ultraviolet rays are made incident upon the specimen through said window as a converged or parallel ultraviolet beam.
	abstract	An X-ray mask is integrated with a micro-actuator. The X-ray mask includes a mask portion, a mask holder portion, at least one elasticized supporter and a micro-actuator unit. The mask portion has a thin shuttle mass and an X-ray absorber attached on the shuttle mass. The mask holder portion is formed around the mask portion with a predetermined distance maintained therebetween. The elasticized supporter connects the mask portion and the mask holder portion elastically. The micro-actuator unit is prepared between the mask portion and the mask holder portion to precisely control a position of the mask portion when a voltage is applied.
048715085	abstract	A core of a light water boiling reactor comprises a plurality of vertical fuel assemblies (10) and a plurality of control rods, each control rod comprising four vertical blades arranged in a cruciform. The control rods are arranged with each one of their blades between two fuel assemblies located in the same row, such that each control rod together with four fuel assemblies arranged around the blades of the control rod form a unit, the control rod unit (30, 30-o), having an at least substantially square cross-section. The control rod units are arranged in a symmetrical lattice with each control rod unit included in two rows of control rod units perpendicular to each other. After a period of operation of the reactor, when exchanging fuel rods which are present in the reactor at the time of exchange and have been used during the operating period, for new control rods, there are arranged in some control rod units (dark squares) control rods with a reactivity worth which is higher than the original reactivity worth of the control rods which have been used, whereas in other control rod units (light squares) there are used control rods which have been used in the reactor during the operating period (FIG. 2).
	description	This application is a divisional application of U.S. Ser. No. 13/760,263, filed on Feb. 6, 2013, entitled ALTERNATE PASSIVE SPENT FUEL POOL COOLING SYSTEMS AND METHODS, and claims priority thereto. The present invention relates generally to alternate passive cooling systems and methods for spent fuel pools in nuclear reactor power plants and in particular, to a mechanism for cooling a spent fuel pool in the event of a loss of the normal active spent fuel pool cooling system which can occur as a result of a loss of onsite and offsite power. A nuclear reactor power plant generates electric power as a result of the nuclear fission of radioactive materials contained within the nuclear reactor. Due to the volatility of this nuclear reaction, nuclear reactor power plants are designed in a manner to assure that the health and safety of the public is maintained. In conventional nuclear reactors, the radioactive material used for generating electric power is nuclear fuel. The nuclear fuel is depleted, i.e., spent, over the life of the fuel cycle. The nuclear fuel is not reprocessed and therefore, the spent fuel is removed at periodic intervals from the nuclear reactor. Even after removal, the spent fuel continues to generate intense heat, called “decay heat,” and remains radioactive. Decay heat naturally decreases over time at an exponential rate, but still generates enough energy to require water cooling for several years. Thus, a safe storage facility is needed to receive and store the spent fuel. In nuclear reactor power plants, such as small modular reactors and other pressurized water reactors, a spent fuel pool is provided as a storage facility for the spent fuel following its removal from the reactor. The spent fuel pool is typically constructed of concrete and contains a level of water that is sufficient in order to maintain the nuclear fuel immersed underwater. The spent fuel pool is typically at least 40 feet deep. The quality of the water is also controlled and monitored to prevent fuel degradation in the spent fuel pool. Further, the water is continuously cooled to remove the heat which is produced by the spent fuel in the pool. A typical nuclear reactor power plant includes an active spent fuel pool cooling system which is designed for and capable of removing decay heat generated by stored spent fuel from the water in the spent fuel pool. “Active” cooling systems include those which require alternating current electric power to operate pumps or valves in order to achieve the desired cooling function. Removal of the decay heat is necessary to maintain the spent fuel pool water temperature within acceptable regulatory limits and prevent unwanted boiling of the water in the spent fuel pool. In some pressurized water reactors, such as the AP1000 design which includes Westinghouse's Passive Core Cooling System, the spent fuel pool cooling system is a non-safety-related system. In other pressurized water reactor designs, such as non-AP1000 designs, the spent fuel pool cooling system is a safety-related system. The active spent fuel pool cooling system typically includes a spent fuel pool pump to circulate high temperature water from the spent fuel pool and through a heat exchanger to cool the water. The cooled water is then returned to the spent fuel pool. The spent fuel pool cooling system can include two mechanical trains of equipment. Each train having one spent fuel pool pump, one spent fuel pool heat exchanger, one spent fuel pool demineralizer and one spent fuel pool filter. The two trains of equipment can share common suction and discharge headers. In addition, the spent fuel pool cooling system includes the piping, valves and instrumentation necessary for system operation. Typically, one train is continuously cooling and purifying the spent fuel pool while the other train is available for water transfers, in-containment refueling water storage tank purification, or alignment as a backup to the operating train of equipment. FIG. 1 shows an active spent fuel pool cooling (SFPC) system 10 during its normal operation in accordance with the prior art. The SFPC 10 includes a spent fuel pool 5. The spent fuel pool 5 contains a level of water 16 at an elevated temperature as a result of the decay heat generated by the spent fuel (not shown) that is transferred from the nuclear reactor (not shown) into the spent fuel pool 5. The SFPC system 10 includes trains A and B. Trains A and B are employed to cool the water in the spent fuel pool 5. As previously described, it is typical to operate one of train A or train B to continuously cool and purify the spent fuel pool 5 while the other train is available as a back-up. Each of trains A and B include a SFPC pump 25, a SFPC demineralizer and filter system 45. Trains A and B share a common suction header 20 and a common discharge header 50. In each of trains A and B, water exits the spent fuel pool 5 through the suction header 20 and is pumped through the SFPC pump 25 to the SFPC heat exchanger 30. In the SFPC heat exchanger 30, a flow line 40 passes water from the component cooling water system (CCWS) (not shown) through the SFPC heat exchanger 30 and back to the CCWS. The heat from the water entering the SFPC heat exchanger 30 (from the spent fuel pool 5) is transferred to the water provided by the flow line 40 and is returned back to the CCWS through the flow line 40. Cooled water exits the SFPC heat exchanger 30 and passes through the SFPC demineralizer and filter system 45 positioned downstream of the SFPC heat exchanger 30. Purified, cooled water exits the demineralizer and filter system 45, is transported through the common discharge header 50, and is returned to the spent fuel pool 5. In addition to the active SFPC system shown in FIG. 1, it is also known in the art to employ passive designs to mitigate accident events in a nuclear reactor without operator intervention or off-site power. These passive designs emphasize safety features that rely on natural forces, such as pressurized gas, gravity flow, natural circulation flow, and convection, and do not rely on active components (such as, pumps, fans or diesel generators). Further, passive systems are designed to function without safety grade support systems (such as, AC power, component cooling water, service water, and HVAC). A passive spent fuel pool cooling system can be designed such that the primary means for spent fuel protection is provided by passive means and relies on the boiling of the spent fuel pool water inventory to remove decay heat. For example, if a complete loss or failure of an active spent fuel pool cooling system is assumed, spent fuel cooling can be provided by the heat capacity of the water in the spent fuel pool. The decay heat of the spent fuel is transferred to the water in the pool and, after some period of time, causes the water to boil. The boiling action of the pool water produces non-radioactive steam, which transfers the decay heat energy to the atmosphere. After a specific period of time, additional water will need to be added to the SFP to makeup for the loss of inventory due to boiling. Water make-up can be provided to the spent fuel pool by alternate means to maintain the pool water level above the top of the spent fuel and boiling of the pool water can continue to provide for the removal of decay heat. Boiling of the spent fuel pool water releases large quantities of steam into the fuel handling area. The steam mixes with air in the fuel handling area to form a steam/air mixture which is then passively vented through an engineered relief panel to the atmosphere to reduce the temperature in the fuel handling area. The boil-off rate of the spent fuel pool water is highly dependent on the decay heat generated by the fuel in the pool. The amount of decay heat generated depends on how recently fuel has been offloaded into the spent fuel pool. During the first 72 hours of a loss of cooling event, water is typically supplied from safety-related sources, such as the spent fuel pool inventory, water stored in the cask wash-down pit, and water from the fuel transfer canal. If additional makeup water is required beyond 72 hours, water from the passive containment cooling system ancillary water storage tank can be provided to the spent fuel pool. The invention provides an alternate passive spent fuel cooling system and method that is employed to remove decay heat generated by the spent fuel in the event of a loss of onsite and offsite power wherein the active spent fuel pool cooling system is not available to cool the spent fuel pool. In one aspect, the invention provides a passive cooling system for a spent fuel pool in a nuclear power plant to provide cooling in the absence of onsite and offsite power. The system includes a gap having a first side and a second side formed at least partially along a periphery of the spent fuel pool, a heat sink, one or more thermal conductive members having a first end connected to the second side of the gap and a second end connected to the heat sink wherein the one or more members are structured to transport heat from the gap to the heat sink, a water supply system including a water source and a discharge header having a first end connected to the water source and a second end connected to the gap, and a thermal switch mechanism having an activate position and a deactivate position which is structured to deliver water from the water system into the gap when in the activate position and structured to inhibit the release of water from the water system into the gap when in the deactivate position. When the thermal switch mechanism is in the activate position, heat generated in the spent fuel pool is conducted through the gap by the water therein and transported through the one or more conductive members to the heat sink. In certain embodiments, the passive cooling system can include one or more conductive cooling fins attached to the second end of the one or more members to enhance transfer of decay heat from the members to the heat sink. Further, the passive cooling system can include a valve located in the discharge header and structured to be positioned in the open position to allow the flow of water in the gap and in the closed position to inhibit the flow of water in the gap. Furthermore, the passive cooling system can be incorporated in a nuclear power plant containing a pressurized water reactor. In certain embodiments, the first side of the gap can be formed by a spent fuel pool liner. The second side of the gap can be formed by a concrete wall. The gap can be continuous or the gap can be partitioned into a plurality of channels. In certain embodiments, the discharge header is located at the top or near the top of the gap. Wherein the gap is partitioned into a plurality of channels, each of the channels can have a discharge header located therein. Moreover, the thermal switch can activate in response to a loss of offsite power event with or without availability of emergency diesels operable to supply AC electrical power to active spent fuel pool cooling pumps. Further, the thermal switch can activate in response to a station blackout when all backup sources of DC electrical power are exhausted. In certain embodiments, the heat sink can be selected from the group consisting of a mass of earth, a mass of concrete or other material used in foundations or floors of spent fuel pool structures and combinations thereof-. In another aspect, the invention provides a method of passively cooling a spent fuel pool in a nuclear power plant in the absence of onsite and offsite power. The method includes forming a gap having a first side and a second side at least partially along a periphery of the spent fuel pool, obtaining a heat sink, at least partially filling the gap with water, conducting heat from the spent fuel pool through the at least partially water-filled gap, and transporting the heat from the gap to the heat sink. In certain embodiments, the gap is at least partially filled with water by discharging water from a water source through a discharge header and into the gap. The discharge header can include a means of controlling the flow of water. The means can include a valve which has an open and closed position. The first side of the gap can be the liner of the spent fuel pool and the second side of the gap can be the concrete wall of the spent fuel pool. The gap can be partitioned into a plurality of channels. Each of the channels can include a discharge header for delivering water thereto. In certain embodiments, the method includes transporting heat from the gap to the heat sink by obtaining at least one thermal conductive member, one end being connected to the second side of the gap and another end being connected to the heat sink, conducting the heat through the air gap, transporting the heat through the at least one thermal conductive member and to said heat sink The invention relates to passive systems and methods for cooling a spent fuel pool in a nuclear reactor power plant including designs such as small modular reactors, other pressurized water reactors and boiling water reactors. In particular, the passive systems and methods of the invention are employed in the event of a loss of the normal active spent fuel pool cooling system which can occur as a result of the loss of onsite and offsite power, e.g., a station blackout. The invention includes employing a heat sink for removing decay heat from the spent fuel pool. The heat sink can include a wide variety of materials that can absorb heat, such as soil/dirt, filler, such as rock or concrete, and combinations thereof. In certain embodiments, the heat sink is a mass of earth, a mass of concrete or other material used in foundations or floors of spent fuel pool structures and combinations thereof. In response to a station blackout event, decay heat is removed from the spent fuel pool and transferred to the heat sink. The heat sink is located in relative close proximity to the spent fuel pool. In a typical nuclear reactor power plant design, the design and architecture of the spent fuel pool and surrounding structures may preclude the use of the area immediately surrounding, e.g., adjacent to, the spent fuel pool, as a heat sink. Thus, there may be a need to provide a means of transporting the heat removed from the spent fuel pool to the heat sink. The means of transportation can vary. In certain embodiments, the heat is transported using one or more highly thermal conductive members, such as heat pipes. Further, during normal operation, a mechanism is needed to prevent the transport of heat from the spent fuel pool to the heat sink such that the heat sink remains cool during normal operation and, is available and capable of serving as a heat sink during an event, such as station blackout. In the invention, the inside surface of the spent fuel pool wall is modified to provide a gap along at least a portion of the periphery of the spent fuel pool, forming an inner spent fuel pool wall and an outer spent fuel pool wall. Thus, one side of the gap is formed by the inner spent fuel pool wall and the other side of the gap is formed by the outer spent fuel pool wall. The inner spent fuel pool wall can be formed by an inner stainless steel liner and the outer spent fuel pool wall is typically constructed of concrete, such as steel-lined reinforced concrete. The width and depth of the gap can vary. The area located beyond (e.g., on the outside of) the outer spent fuel pool wall can be used as the heat sink. During normal operation of the nuclear reactor power plant, the gap contains air to impede the conductive flow of heat from the spent fuel pool. However, in the event of an emergency, such as a station blackout, the gap can be at least partially filled with water. Water is more conductive than air, e.g., approximately 20 times more conductive. Thus, the heat is conducted from the spent fuel pool and into the at least partially water-filled gap. The water can be supplied to the gap using various conventional systems and methods. In certain embodiments, a water source is attached to a discharge header or manifold which is connected to the outer wall of the spent fuel pool and discharges/empties into the gap. The water source can be in various forms, such as a tank or reservoir. The discharge header can include a fail-safe passive valve, such as an air-operated solenoid valve. During normal operation, the valve can be closed in order to prevent water from flowing into the gap and to inhibit the transfer of heat through the thermal conductive members. In the event of a loss of power, e.g., station blackout, the valve can open (e.g., fail open) using stored energy, typically in the form of a compressed spring, to allow water from the water source to flow through the discharge header and empty into the gap. In turn, the thermal conductive members are activated to transport heat from the gap to the heat sink. In certain embodiments, the gap is a continuous structure along the periphery of the spent fuel pool. In other embodiments, the gap can be partitioned into a plurality of channels. In accordance therewith, the header can extend continuous around the periphery of the spent fuel pool or the header can correspond to channels formed within the gap such that a header is positioned within each channel. The header typically is positioned at or near the top of the gap. During the emergency event, heat is removed from the spent fuel pool and conducted across the gap to the thermal conductive members, such as, for example, heat pipes. The outer spent fuel pool wall, e.g., concrete wall, for example, steel-lined reinforced concrete, of the gap provides the attachment point for the thermal conductive members. These conductive members can penetrate through the outer spent fuel pool wall such that one end is adjacent to or in contact with the gap. The other end of the conductive member can be directly or indirectly connected to the heat sink. In certain embodiments, the heat pipes transport heat from the wall of the spent fuel pool to the heat sink. In general, the heat pipes use evaporation and condensation of an intermediate fluid to produce very high thermal conductance. In certain embodiments, the valve is employed to activate and deactivate the highly conductive members. During normal operation, e.g., when the active spent fuel pool cooling system is available and operable, the valve is positioned to prevent water flow and deactivate the highly conductive members in order to inhibit the transport of heat from the spent fuel pool to the heat sink. However, upon the loss of normal pool cooling, the valve is positioned to allow water flow and activate the highly conductive members in order to allow heat to be removed from the spent fuel pool and transported to the heat sink. FIG. 2 shows a top view of an alternate passive spent fuel pool cooling system 1 in accordance with certain embodiments of the invention. The system 1 includes a spent fuel pool 5′ and a gap 7 formed along the periphery of the spent fuel pool 5′. The gap 7 is formed by an inner wall 9, e.g., liner, of the spent fuel pool 5′ and an outer wall 11, e.g., secondary concrete wall, of the spent fuel pool. The width 13 of the gap 7 and its depth (not shown) can vary. Further, shown in FIG. 2 is a plurality of heat pipes 15 each having a first end 17 and a second end 19. The first end 17 is connected to the outer wall 11 and the second end 19 is connected to a heat sink 23. In certain embodiments, the second end 19 can be connected to a heat distributor 21. The heat distributor 21 includes an array of metallic, conductive cooling fins 22 with a large surface area that is able to distribute heat from the concentrated locations at the second end 19 of the plurality of heat pipes 15 to a larger area in the heat sink 23. FIG. 2 shows only one second end 19 connected to a heat distributor 21, however, in certain embodiments, more than one second end 19 can be connected to a heat distributor 21. For example, in certain embodiments, each and every second end 19 of the plurality of heat pipes 15 is connected to a heat distributor 21. Further, FIG. 2 shows four cooling fins 22, however, in certain embodiments, the number of cooling fins 22 may be more or less than four. Furthermore, in certain embodiments, the cooling fins 22 can be replaced with another structure suitable for distributing heat from concentrated locations. As above-mentioned, the gap 7 is filled with air during normal operation and with water during an event, such as station blackout. During an event, heat is conducted from the spent fuel pool 5′, across the gap 7, into the first end 17, through the heat pipes 15, out of the second end 19, and into the heat sink 23. FIG. 3 shows a water supply system 25′ during normal operation for controlling the flow of water into the gap 7 (shown in FIG. 2) in accordance with certain embodiments of the invention. FIG. 3 shows gap 7 filled with air (not shown) and a header 27 located near or at the top of the gap 7. The header 27 is filled with water (not shown) which is supplied from a water tank 26 connected to the header 27. Positioned within the header 27 is a solenoid valve 29 which is supplied with site power to stay energized and closed during normal operation. FIG. 4 shows a water supply system 25″ during a loss of onsite and offsite power event, e.g., station blackout, for controlling the flow of water into the gap 7 (shown in FIG. 2) in accordance with certain embodiments of the invention. FIG. 4 shows gap 7, header 27, water tank 26 and solenoid valve 29 as shown in FIG. 3. However, in FIG. 3 during normal operation, the gap 7 contains air and the solenoid valve 29 is closed to prevent the flow of water into the gap and in FIG. 4 during a loss of power event, the solenoid valve 29 is open to allow water to flow from the water tank 26, through the header 27 and into the gap 7. Since water is significantly more conductive than air, the heat is conducted across the gap 7 to the heat pipes 15 and the heat distributor 21 (shown in FIG. 2) and subsequently distributed into the heat sink 23 (shown in FIG. 2). FIG. 5 shows a section view of the alternate passive spent fuel pool cooling system 1 shown in FIG. 2 including the spent fuel pool 5′, gap 7, inner wall 9, outer wall 11, heat pipes 15 and first end 17. In addition, FIG. 5 shows the gap 7 empty of water under normal operating conditions. FIG. 6 shows a section view of the alternate passive spent fuel pool cooling system 1 shown in FIG. 2 including the spent fuel pool 5, gap 7, inner wall 9, outer wall 11, heat pipes and first end 17. Further, FIG. 6 shows the gap 7 is filled with water (shown shaded) under event conditions, e.g., station blackout, to enable thermal conduction through the heat pipes 15 and into the heat sink 23 (shown in FIG. 2). While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.
	summary
	abstract	A substrate holding apparatus for use in ion implanters includes two or more substrate holders that can adopt interchangeable positions, thereby allowing one substrate holder to scan a substrate through an ion beam while substrates can be swapped on the other substrate holder. The substrate holder assembly includes a base rotatable about a first axis and at least two support arms extending from the base to ends provided with substrate holders. Rotating the base allows the substrate holders to move between designated positions. One designated position may correspond to a position for implanting a substrate and another designated position may correspond to a loading/unloading station.
052710530	claims	1. A holddown leaf spring assembly for a nuclear fuel assembly with an upper end fitting, said leaf spring assembly including spring retention means and comprising, a unitary elongated metal bar leaf spring having two leg portions joined by an arcuate transition portion therebetween, said transition portion being spaced from the fuel assembly end fitting to provide an improved open flow path therebetween, the end of each of said leg portions opposite said transition portion is adapted to be mounted to the fuel assembly end fitting by leaf spring retention means. 2. The holddown leaf spring assembly of claim 1 in which the leg portions have a tapered width, the transition portion is adjacent the reduced width end of each of said tapered width leg portions and the wider opposite end of the tapered width leg portions from the reduced width end are adapted to be mounted to the fuel assembly end fitting by spring retention means. 3. The holddown leaf spring assembly of claim 2 in which the spring retention means are screws within openings in said opposite ends, and caps. 4. The holddown leaf spring assembly of claim 2 in which the spring retention means are pins within openings in said wider opposite ends and said wider opposite ends are received and retained by said pins in spring retaining slots in the upper end fitting. 5. The holddown leaf spring assembly of claim 4 in which said wider opposite ends are straight in order to facilitate their insertion into spring retaining slots in the upper end fitting. 6. The holddown leaf spring assembly of claim 2 in which two stacks of two unitary elongated metal bars make up the leaf springs of the assembly. 7. The holddown leaf spring assembly of claim 1 in which the (fuel assembly end fitting has nozzle openings adjacent its edge margins below) leaf spring bars have a shape which spaces the transition portions of the leaf spring bars (and spaced therefrom) away from any adjacent associated fuel assembly upper end fitting nozzle openings for an improved open flow path from the nozzle openings upwardly.
	abstract	Irradiating assemblies can have a housing with a reflector extending linearly parallel to a lamp. Radiation can be emitted from one opening, for example in a bottom portion of the housing, as well as from another opening, for example a side opening in the housing. Irradiating assemblies can also have first and second reflector portions at angles with respect to each other wherein radiation is reflected out of a housing that does not have an end reflector. Irradiating assemblies can be configured to have cooling flow openings in side walls so that cooling fluid such as air can flow between the side walls and adjacent surfaces of a reflector. Irradiating assemblies can incorporate lamps having first and second electrodes wherein the first and second electrodes are oriented at an angle with respect to each other. Methods of irradiating material may include irradiating a surface with emissions from a first portion of an assembly and irradiating a surface with emissions from a second portion of an assembly different from the first portion.
	description	The present invention relates to a method for treating tritium water-containing raw water in which, by gasifying tritium water-containing raw water through alkali water electrolysis, tritium concentration is diluted to 1/1,244 relative to the tritium concentration in the raw water, and simultaneously, volume of the tritium water-containing raw water is reduced. The present invention also relates to a method of taking out tritium in an amount of 1/20 of the permissible discharge standard to open air and leading it to high altitudes separated from any living organisms. The present invention also relates to a method for recovering tritium as concentrated tritium water-containing water by reacting tritium-containing hydrogen gas with water vapor. The present invention also relates to a method for treating tritium water-containing raw water in which raw water hardly containing impurities like chloride ions is used as the tritium water-containing raw water, and by gasifying the raw water through continuous electrolysis, and thereby tritium concentration is diluted, and simultaneously the volume of the tritium water-containing raw water is reduced. The present invention also relates to a method for treating tritium water-containing raw water in which, after performing the continuous electrolysis, alkali water electrolysis is further performed for the separated tritium water-containing water while recovering an alkali component used for the electrolysis. The present invention also relates to a method for treating tritium water-containing raw water in which raw water containing a large amount of impurities like chloride ions is used as the tritium water-containing raw water, continuous electrolysis is performed after removing the impurities and tritium concentration is diluted, and simultaneously the volume of the tritium water-containing raw water is reduced. The present invention also relates to a method for treating tritium water-containing raw water in which, after performing the continuous electrolysis, the electrolysis is further performed while recovering an alkali component used for the electrolysis and volume of the tritium water-containing water is further reduced. Most of the tritium on earth is present as an oxide like tritiated water, i.e., tritium water. Concentration of tritium water which circulates in air is believed to have almost a constant value in animals and plants of all ages in any area. From the reduced amount of concentration in water, a period separated from the air circulation can be determined, and dating of underground water can be also made. Concentration of tritium water is also used for actual investigation of a flow of underground water in the field of civil engineering and agriculture. Tritium is mixedly present in water as tritium water including oxygen, and it is widely present in water resources including water vapor, rainfall, underground water, stream water, lake water, sea water, drinking water, and a living organism as a gas phase, a liquid phase, or a solid phase. Natural tritium is produced by a reaction between cosmic ray and air. However, due to low production probability, its amount is extremely small. Meanwhile, the tritium produced by the nuclear test in 1950s, a nuclear reactor and the reprocessing of nuclear fuel has been discharged and present in large amount in an environment (fallout tritium). Furthermore, compared to an external system, tritium produced during operation or maintenance of the reactor or reprocessing of nuclear fuel is accumulated and localized at higher level in facilities related to a nuclear reactor. However, due to the reason that the chemical property is almost not different from that of hydrogen, it is discharged under management to atmosphere or sea. The highest value measured in Japan is 1,100 Bq/L which has been measured on Jun. 21, 2013 at the port of the first nuclear power plant of Fukushima where the nuclear disaster had happened. Since it is difficult for tritium to be separated chemically from hydrogen, a method for physical separation has been tried. However, it is still at a test level and practical success is yet to be made. Thus, radioactivity of the tritium discharged into the environment due to nuclear power plant disaster or the like cannot be removed with a current technology. The contaminated water containing tritium produced from the first nuclear power plant of Fukushima may reach 800,000 m3 or so in the future, and it is desired to have a method for effective treatment therefor as soon as possible. Meanwhile, as the tritium concentration is at extremely low level, it is general to have electrolysis concentration for improving the measurement precision at the time of measuring the concentration. Herein, a method of preparing a sample solution containing dissolved electrolyte and performing electrolysis across a plate-like panel is known as the electrolysis concentration of heavy water of a related art. There is HDO or HTO as water included in an electrolyte solution in addition to H2O. They are decomposed into hydrogen and oxygen according to water electrolysis in general. However, due to the isotope effect, decomposition of H2O occurs prior to decomposition of HDO or HTO, and therefore as the concentration of deuterium or tritium increases in the electrolyte solution, concentration occurs. Nickel is used as an anode used for the electrolysis concentration. Steel, iron, nickel and the like are used as a cathode. Those electrodes are cleaned and sample water which is prepared by adding dilute sodium hydroxide as a support salt to water solution containing heavy water is added to a glass container. Then electrolysis is performed by applying electric current. At that time, while the current density is set at 1 to 10 A/dm2 or so and the solution temperature is kept at 5° C. or lower to prevent evaporation of water caused by heating, the electrolysis is generally continued until the liquid amount is reduced to 1/10 or so to have the concentration of deuterium. Namely, the electrolysis concentration of tritium is based on the property that, like the case of deuterium, electrolysis of tritium water is more difficult than water with light hydrogen. Regarding the electrolysis method including insertion of a metal electrode into an aqueous alkali solution, various studies have been already made so that a standard method is present as an official manual. According to this method, tritium concentration is concentrated with 1 stage. However, in terms of an actual case, there are several problems in the electrolysis concentration of a related art, i.e., the operational works are complicated, tritium concentration rate is limited by the upper limit of electrolyte concentration, mixture gas of hydrogen and oxygen is produced to yield a risk of explosion, it takes long time for the electrolysis, and the method is not suitable for a large-scale treatment. As the technology is determined from the viewpoint of separating and capturing a barely-contained material with 1 stage, the above problems are mainly caused by using an aqueous alkali solution electrolysis of a related art in which handling an alkali water electrolytic water solution is difficult, separating the gas generated from an anode is difficult, increasing electrolytic current is difficult due to forming of air bubbles on a metal surface, or the like. In this regard, as an electrolysis method for water which receives attention in recent years, a water electrolysis using a solid polymer electrolyte (hereinbelow, referred to as “SPE”) can be mentioned (hereinbelow, referred to as “SPE water electrolysis”). The first SPE water electrolysis is made by General Electric Company of USA, by applying the technology of fuel cell in early 1970s. With regard to the structure of electrolysis part, both surfaces of a SPE membrane are sandwiched between porous metal electrodes, and by immersing them in pure water and just applying electric current, electrolysis is caused to release decomposed gas from the porous electrodes. SPE is a kind of a cation exchange resin, and it has a structure in which a sulfonic acid group or the like for having ion transport is chemically bound to a polymer chain. When electric current is applied between two electrodes, water is decomposed and oxygen gas is produced at the anode and hydrogen ions are produced. Those hydrogen ions are transported to the cathode after moving through the sulfonic acid groups of SPE, and after taking electrons, hydrogen gas is generated. Apparently, SPE itself does not undergo any change and is maintained in a solid phase. In a case of using the SPE for electrolysis concentration of tritium, it is expected to have the following advantages compared to a method of a related art. 1) Distilled water can be directly decomposed. Namely, dissolution and neutralization of an electrolyte and removal of an electrolyte, which are essential in aqueous alkali solution electrolysis, are not necessary and the rate of volume decrease of sample water is limitless, in principle. 2) As the electrode surface is not covered by air bubbles, electrolysis can be carried out with high electric current and thus the time for electrolysis can be shortened. 3) As the hydrogen gas and oxygen gas are separately produced at different sides of a SPE membrane, gas treatment is easy, and it is much safer than a method of a related art in which explosive mixture gas is handled. Furthermore, regarding the electrolysis concentration method of heavy water based on SPE water electrolysis, there are Patent Literatures 1 and 2 suggested by the applicant company and Non Patent Literature 1. However, in a case of using Patent Literatures 1 and 2 and Non Patent Literature 1, an application can be made for a device for analysis or concentration of small scale, but they are not suitable for a treatment of large scale based on the following reasons. Since an electrolyte solution to be used is pure water, to have no flow of electric current in the electrolyte solution, the solid polymer membrane as a constitutional element needs to be strongly clamped at an anode and a cathode with surface pressure of 20-30 Kg/cm2 or so. As such, it is required for each member of an electrolysis bath to have high strength. However, having a large reaction area like 1 m2 or more is not practical when economic efficiency or operational property is considered. Also, they are not suitable for electrolysis concentration or fractionation of raw water containing large volume of heavy water due to high cost involved with facilities or the like. Patent Literature 1: JP 8-26703 A (U.S. Pat. No. 3,406,390) Patent Literature 2: JP 8-323154 A (U.S. Pat. No. 3,977,446) Non Patent Literature 1: Tritium Electrolytic Enrichment using Solid Polymer Electrolyte (RADIOISOTOPES, Vol. 45, No. 5 May 1996 (published by Japan Radioisotope Association)) An object of the present invention is to solve the problems of a prior art and to provide a method for treating tritium water-containing raw water which is suitable for large-scale treatment using electrolysis. More specifically, an object of the present invention is to provide a method for diluting tritium at the concentration of 1/1,244 by gasifying tritium water-containing raw water through continuous alkali water electrolysis under continuous supply of raw water for conversion into tritium-containing hydrogen gas and oxygen gas to lower the influence of tritium on a living organism. An object of the present invention is to provide a method of taking out tritium in an amount of 1/20 or less of the permissible discharge standard to open air and leading it to high altitudes separated from any living organisms. An object of the present invention is to provide a method for recovering tritium as concentrated tritium water-containing water by reacting the gasified tritium-containing hydrogen gas with water vapor. An object of the present invention is also to provide a method for allowing continuous electrolysis in the case where raw water hardly containing impurities like chloride ions is used as the raw water containing the tritium water, and thereby diluting tritium concentration and reducing volume of tritium water-containing raw water. An object of the present invention is also to provide a method for, after performing the continuous electrolysis of tritium water-containing raw water, treating tritium water-containing raw water in which alkali water electrolysis is further performed with batch supply while recovering the alkali component used for the electrolysis and thereby diluting tritium concentration and reducing the volume of tritium water-containing water. An object of the present invention is also to provide a method of performing the above-mentioned continuous electrolysis after removing the impurities in a pre-step in the case where raw water containing impurities like a large amount of chloride ions is used as the tritium water-containing raw water, and thereby diluting tritium concentration and reducing volume of tritium water-containing raw water. An object of the present invention is also to provide a method for, with regard to those methods, after performing the continuous electrolysis of tritium water-containing raw water, treating tritium water-containing raw water in which alkali water electrolysis is further performed with batch supply while recovering the alkali component used for the electrolysis and thereby diluting tritium concentration and reducing the volume of tritium water-containing water. To achieve the object described above, the first solving means of the present invention is to provide a method for treating tritium water-containing raw water by which tritium water-containing raw water is treated by a first alkali water electrolysis step including steps of: (1) supplying a part of raw water containing tritium water and alkali water to a circulation tank; (2) mixing the raw water with the alkali water in the circulation tank to obtain an electrolyte adjusted so as to have a desired alkali concentration, supplying the electrolyte to an alkali water electrolysis device, and performing electrolysis treatment; (3) supplying the raw water continuously to the circulation tank in an amount which corresponds to raw water lost by the above electrolysis treatment to maintain alkali concentration at an adjusted initial concentration, and continuing the electrolysis treatment while circulating the electrolyte in order to continuously perform the alkali water electrolysis treatment;(4) gasifying the raw water to tritium-containing hydrogen gas and oxygen gas so that tritium concentration is diluted to 1/1,244 relative to tritium concentration in the raw water; and(5) reducing the volume of the raw water. To achieve the object described above, the second solving means of the present invention is to provide a method for treating tritium water-containing raw water in which the tritium-containing hydrogen gas generated by the first alkali water electrolysis step is taken out to open air. To achieve the object described above, the third solving means of the present invention is to provide a method for treating tritium water-containing raw water in which the tritium-containing hydrogen gas generated by the first alkali water electrolysis step is sent to a catalyst tower, the tritium-containing hydrogen gas is reacted with water vapor on a catalyst filled in the catalyst tower, and the tritium is recovered as concentrated tritium water-containing water. To achieve the object described above, the fourth solving means of the present invention is to provide a method for treating tritium water-containing raw water in which the method includes: the first alkali water electrolysis step for performing continuously the alkali water electrolysis treatment; a second distillation step in which, after completion of the first alkali water electrolysis step, the entire amount of the electrolyte remained in the first alkali water electrolysis step is supplied to an evaporator, an alkali component in the electrolyte is recovered as alkali salt slurry, and simultaneously, tritium water-containing water distilled by the evaporator is taken out; and a second alkali water electrolysis step in which the tritium water-containing water taken out by the second distillation step and new alkali water are supplied to a circulation tank, the tritium water-containing water is mixed with the new alkali water in the circulation tank so as to have an electrolyte solution with a desired alkali concentration, electrolysis capacity of an alkali water electrolysis device is adjusted to the capacity suitable for a treatment amount of the electrolyte, an alkali water electrolysis treatment is performed followed by batch treatment, the tritium water-containing water is gasified and converted to tritium-containing hydrogen gas and oxygen gas so that tritium concentration is diluted to 1/1,244 relative to tritium concentration in the tritium water-containing water, and the volume of the raw water is reduced, if necessary, further comprising a step of repeating several times the second distillation step and the second alkali water electrolysis step until the completion of the batch treatment in which, at the time of repeating several times, the capacity of the alkali water electrolysis device used for the second alkali water electrolysis step is gradually reduced and the treatment is repeated. To achieve the object described above, the fifth solving means of the present invention is to provide, regarding the above first solving means, a method for treating tritium water-containing raw water in which, when raw water which contains impurities including a large amount of chloride ions is used as the tritium water-containing raw water, a first distillation step for removing the impurities is further provided as a pre-step of the first alkali water electrolysis step, and in the first distillation step, the raw water which contains impurities including the chloride ions is supplied to the evaporator and the impurities are removed as salt slurry, and simultaneously, the tritium water-containing raw water after removing the impurities is taken out and then continuously supplied to be treated by the first alkali water electrolysis step. To achieve the object described above, the sixth solving means of the present invention is to provide, regarding the above fourth solving means, a method for treating tritium water-containing raw water in which, when raw water which contains impurities including a large amount of chloride ions is used as the tritium water-containing raw water, a first distillation step for removing the impurities is provided as a pre-step of the first alkali water electrolysis step, and in the first distillation step, the raw water which contains impurities including the chloride ions is supplied to the evaporator and the impurities are removed as salt slurry, and simultaneously, the tritium water-containing raw water after removing the impurities is taken out and then continuously supplied to be treated by the first alkali water electrolysis step. To achieve the object described above, the seventh solving means of the present invention is to provide, regarding the above fifth or sixth solving means, a method for treating tritium water-containing raw water in which, in the first distillation step, the salt slurry is concentrated and then separated and recovered as a solid matter. To achieve the object described above, the eighth solving means of the present invention is to provide, regarding the above fourth solving means, a method for treating tritium water-containing raw water in which, in the second distillation step, the alkali salt slurry is concentrated and then separated and recovered as a solid matter. To achieve the object described above, the ninth solving means of the present invention is to provide, regarding the above fourth solving means, a method for treating tritium water-containing raw water in which, in the first alkali water electrolysis step, alkali water with relatively high concentration is used as the alkali water, the electrolysis treatment is performed at relatively high current density, and in the second alkali water electrolysis step, alkali water with relatively low concentration is used as the alkali water, the electrolysis treatment is performed at relatively low current density. To achieve the object described above, the tenth solving means of the present invention is to provide, regarding the above first solving means, a method for treating tritium water-containing raw water in which, in the first alkali water electrolysis step, 15% by mass or more of alkali water is used as the alkali water, and the electrolysis treatment is performed at current density of 15 A/dm2 or higher. To achieve the object described above, the eleventh solving means of the present invention is to provide, regarding the above fourth solving means, a method for treating tritium water-containing raw water in which, in the second alkali water electrolysis step, 2 to 10% by mass of alkali water is used as the alkali water, and the electrolysis treatment is performed at current density of 5 to 20 A/dm2. (1) According to the present invention, by gasifying tritium water-containing raw water and converting it to tritium-containing hydrogen gas and oxygen gas, the tritium concentration can be diluted to 1/1,244, and the influence of tritium on living organism can be reduced. Furthermore, although it is preferable that the whole amount of tritium water-containing raw water is treated by alkali water electrolysis. If the volume of the tritium water is large or there is any other reason related to economic efficiency or the like, the alkali water electrolysis can be carried out in several divided times. (2) According to the present invention, by gasifying tritium water-containing raw water, the tritium concentration can be diluted to 1/1,244, and thus the tritium can be taken out in an amount of 1/20 or less of the permissible discharge standard to open air and can be led to high altitudes separated from any living organisms. (3) According to the present invention, in the method for performing continuous alkali water electrolysis treatment of tritium water-containing raw water by the first alkali water electrolysis step, as the gasified tritium gas containing hydrogen gas is reacted with water vapor, the treated product can be recovered as concentrated tritium water-containing water. (4) According to the present invention, also for tritium water-containing raw water containing impurities like a large amount of chloride ions, the first distillation step for continuous supply to a distillator is provided as a pre-step to remove the impurities as salt slurry, and thus the effect described above can be obtained. Hereinbelow, a treatment by the first alkali water electrolysis step and a treatment consisting of the first distillation step as a pre-step and the first alkali water electrolysis step are referred to as the “alkali water electrolysis system (I)”. (5) According to the fourth solving means of the present invention, after completion of the continuous electrolysis of the first alkali water electrolysis step in the alkali water electrolysis system (I), the electrolyte solution (alkali water) remained in the first alkali water electrolysis step is treated in batch mode consisting of the second distillation step and the second alkali water electrolysis step provided after the completion of the second distillation step, and thus the alkali component can be recovered as alkali salt slurry by the second distillation step and the distilled tritium water-containing water can be simultaneously taken out. (6) According to the fourth solving means of the present invention, after completion of the continuous electrolysis of the first alkali water electrolysis step in the alkali water electrolysis system (I), the electrolyte solution (alkali water) remained in the first alkali water electrolysis step is subjected to an electrolysis treatment by having the tritium water-containing water which has been taken out after completion of the second distillation step as an electrolyte solution and supplying the electrolyte solution to the alkali water electrolysis device while the electrolysis capacity of an alkali water electrolysis device is adjusted to capacity corresponding to treatment amount of the electrolyte solution during the second alkali water electrolysis step of batch mode. Thereby the tritium water-containing water remained after the treatment by the alkali water electrolysis system (I) is diluted to a permissible discharge standard of tritium or lower and then removed, and the volume of the tritium water-containing raw water can be further reduced. (7) According to the fourth solving means of the present invention, in order to perform a sufficient batch treatment, the volume can be reduced until the tritium water-containing water is almost zero while the volume of the alkali water electrolysis device is gradually decreased (i.e., reducing the facilities) by performing a step for repeating the second distillation step and the second alkali water electrolysis step as the third, the fourth, . . . step. Hereinbelow, the treatment consisting of the second distillation step (used for the third distillation step and the following distillation step) and the second alkali water electrolysis step (used for the third alkali water electrolysis step and the following alkali water electrolysis step) is referred to as the “alkali water electrolysis system (II)”. (8) According to the fifth or the sixth solving means of the present invention, in the case where raw water containing impurities like a large amount of chloride ions is used as the raw water containing tritium water, the impurities are removed as salt slurry by performing the first distillation step as a pre-step of the first alkali water electrolysis step for carrying out the alkali water electrolysis system (I). As such, according to the first alkali water electrolysis step, no impurities are accumulated in the electrolyte solution and the continuous alkali water electrolysis can be carried out smoothly in a stable state for a long period of time. (9) According to the present invention, in the case where the electrolyte remained after completion of the first alkali water electrolysis step for carrying out the alkali water electrolysis system (I) is treated by the alkali water electrolysis system (II), if necessary, the remaining alkali needs to be recovered as an alkali salt every time during the third, the fourth . . . distillation step like the second distillation step when the second alkali water electrolysis step and the following alkali water electrolysis step are repeated several times. As for the facilities for the distillation steps of the second, the third, and the following steps, the facilities of the first distillation step as a pre-step for removing impurities like a large amount of chloride ions in the tritium water-containing raw water can be also used, and thus significant cost saving can be achieved. The amount of the contaminated water containing tritium released from the first nuclear power plant of Fukushima is large, and the storage amount of the contaminated water may be as large as 800,000 m3 in future. The present invention is devised under the object of determining a technology by which the stored tritium-contaminated water in the amount of 800,000 m3 is subjected to a tritium separation treatment with treatment capacity of 400 m3/day and the volume of the tritium-contaminated water is reduced to 1 m3 or less, and eventually to 0, and also realizing the technology in consideration of an area of a plant and cost involved with construction and running the plant. One embodiment of the technology is to convert tritium water in tritium-containing water to tritium gas by continuous electrolysis, and after detoxification and taking out to open air, it is led to high altitudes separated from any living organisms. As described below, according to the present invention, tritium water (HTO) is gasified for conversion into tritium gas (HT) so as to ensure low concentration like 1/20 or less of the permissible discharge standard and the set value of 1 mSv or less per year. The separation coefficient of 1,244 is achieved according to the following calculation formula. The electrolysis reaction is as described below.H2O (L)→H2 (g)+1/202 (g)HTO (L)→HT (g)+1/202 (g) Namely, because the volume of 1 mole of molecular gas is 22.4 L in the standard state, when raw water of 1 L (about 1,000 g) is decomposed and gasified by electrolysis, content of tritium in 1 L of the raw water is diluted by (1000/18)×22.4=1,244 after the gasification. This value of separation coefficient is a numerical value that is within the range of tritium water form. Dose coefficient according to chemical type of tritium and age is shown in Table 1. Based on Table 1, it is found that, in terms of the effective dose coefficient showing directly the influence on a human body and an environment, tritium gas (HT) has influence degree of 1/10,000 compared to tritium water (HTO). TABLE 1Dose coefficients according to chemical forms of tritium and agesDose coefficient (Sv/Bq) (effective dose per unit intake radioactivity)inhalation intakeOral intake(soluble tritium or gaseous tritium) 1AgeHTOOBT2HTO3OBTHT4CH3T3months6.4 × 10−111.2 × 10−106.4 × 10−111.1 × 10−106.4 × 10−156.4 × 10−131years4.8 × 10−111.2 × 10−104.8 × 10−111.1 × 10−104.8 × 10−154.3 × 10−135years3.1 × 10−117.3 × 10−113.1 × 10−117.0 × 10−113.1 × 10−153.1 × 10−1310years2.3 × 10−115.7 × 10−112.3 × 10−115.5 × 10−112.3 × 10−152.3 × 10−1315years1.8 × 10−114.2 × 10−111.8 × 10−114.1 × 10−111.8 × 10−151.8 × 10−13Adult1.8 × 10−114.2 × 10−111.8 × 10−114.1 × 10−111.8 × 10−151.8 × 10−13(Note)1 The dose efficient by inhalation intake of particulate tritium compounds is described in ICRP Publ. 72, p. 44, Table A2.2OBT: Organically Bound Tritium.3Dose from HTO absorbed from skin is not included therein.4Dose by irradiation from HT gas in lungs is not included therein.It is estimated that it increases by about 20% if included.[Source] ICRP: ICRP Publication 72, Pergamon Press, Oxford, (1995)[Source] Hiroshi Takeda et al., “Radiation effects and safety control of tritium”, Journal of Atomic Energy Society, 39 (11), p. 923 (1997). As such, the influence degree of the tritium on a living organism after conversion into tritium gas is also reduced to 1/10,000. Thus, when the effective dose coefficient is considered, it is believed that the separation coefficient equals to 12,440,000. Several embodiments are included in the method for treating tritium water-containing raw water of the present invention. There is an embodiment in which a distillation step for separating and removing impurities like salt, Ca, and Mg contained in water for treatment, an alkali water electrolysis step to take out tritium gas from tritium water to open air to have 1/20 or less of the permissible discharge standard and also 0.047% or less/year of the tritium amount accumulated in the world and to lead the gas to high altitudes separated from any living organisms, and the circulation step and the alkali water electrolysis step are repeated to reduce the amount of the stored “treatment water” to zero at a final step. First, the explanations are given for this embodiment. The contaminated water containing tritium produced by the first nuclear power plant of Fukushima contains a large amount of impurities like chloride ions. When gasification and dilution are performed by alkali water electrolysis, if such raw water is directly subjected to alkali water electrolysis, the chloride ions in the impurities are accumulated. Furthermore, if the chloride ions are present in caustic alkali at solubility level or higher, they are precipitated as chlorides, and thereby the electrolysis may not be continued. In this regard, according to the present invention, in a case of treating this contaminated water, those impurities are removed as salt slurry during a distillation step as a pre-step before the alkali water electrolysis, and the raw water after the removal is continuously subjected to the alkali water electrolysis. However, when the tritium water-containing raw water to be treated contains only a small amount of the impurities like chloride ions, the impurities like chloride ions are not concentrated to the extent such that they can be precipitated as alkali metal even when the alkali water electrolysis is continuously performed. Thus, the above distillation step for removing the chloride ions before the alkali water electrolysis is not necessary. Accordingly, in such case, design can be made such that tritium water-containing raw water is directly introduced to a circulation tank for supplying the raw water to an alkali water electrolysis device. In the present invention, the “case where the tritium water-containing raw water contains only a small amount of the impurities like chloride ions” means a case where impurities like chloride ions are hardly contained in the tritium water-containing raw water, or a case where the impurities are contained in an amount to precipitate as chlorides to the extent such that electrolysis cannot be continuously performed. Furthermore, when the impurities like chloride ions precipitate as chlorides, it is possible that part of them are drawn to be removed from a circulation pipe during the alkali water electrolysis. According to the present invention, in the first alkali water electrolysis step of the alkali water electrolysis system (I), raw water containing only a small amount of impurities like chloride ions or raw water from which a large amount of impurities contained therein are removed by the first distillation step is used as tritium water-containing raw water, and the treatment is carried out while supplying continuously raw water in an amount corresponding to the amount of raw water lost by the alkali water electrolysis treatment from a storage tank to a circulation tank provided in the first alkali water electrolysis step. Specifically, the electrolysis is continuously performed by adjusting the alkali concentration to a desired initial concentration in the circulation tank to prepare an electrolyte and circulating the electrolyte while maintaining the alkali concentration. By electrolyzing the entire amount of the raw water stored in the storage tank as described above, the tritium water-containing raw water in the raw water is gasified and converted into tritium-containing hydrogen gas and oxygen gas. As a result, compared to a case of tritium water before the gasification, the tritium concentration is diluted to 1/1,244. Furthermore, it is effective to perform the alkali water electrolysis system (II) which consists of the second alkali water electrolysis step in which the electrolyte remaining in the first alkali water electrolysis step after the above treatment is taken out and subjected to a batch treatment, the alkali is recovered as slurry, and the electrolysis is carried out while the electrolysis capacity of the alkali water electrolysis device is adjusted to the capacity corresponding to the treatment amount of the remaining electrolyte, this embodiment will be explained later. The tritium gas containing hydrogen gas which is obtained by gasifying the tritium water-containing raw water after the treatment of the above-mentioned first alkali water electrolysis step may be directly discharged into open air, or the tritium gas containing hydrogen gas may be delivered to a catalyst tower and reacted with water vapor on a catalyst filled in the catalyst tower and recovered as water containing concentrated tritium water (HTO). The reaction formula for such case is as follows.Catalyst layer H2O (g)+HT (g)→HTO (g)+H2 (g)Absorption layer H2O (L)+HTO (g)→HTO (L)+H2O (g) Hereinbelow, the embodiments of the present invention are explained with reference to the drawings. FIG. 1 is a flow chart illustrating the treatment by the alkali water electrolysis system (I) of the first embodiment of the present invention, which can be applied to the tritium water-containing raw water by which, if impurities like chloride ions are not contained, or, even when they are contained, operation of the electrolysis system is not inhibited. In such case, a treatment is carried out, without having a pre-step for removing impurities, alkali water electrolysis of tritium water-containing raw water is continuously performed by the first alkali water electrolysis step while constant alkali concentration is maintained. Hereinbelow, the first embodiment of the present invention is explained with reference to the flow chart of FIG. 1. The alkali water electrolysis system shown in FIG. 1 is the alkali water electrolysis system (I) which uses the first alkali water electrolysis step, in which the alkali water electrolysis system is composed of a raw water storage tank 1, a raw water treatment bath 2, a pump 7, an alkali water electrolysis bath 8, a circulation tank 9, electrolyte circulation pipes 10, 11, supply pumps 12, 13, and coolers 14, 15. The alkali water electrolysis bath 8 is composed of an anode chamber 16 for accommodating an anode, a cathode chamber 17 for accommodating a cathode, and a diaphragm 18 for separating the anode chamber 16 from the cathode chamber 17. According to the first embodiment, a below-described distillation step for removing impurities like chloride ions that are contained in raw water as tritium water-containing raw water is not necessary, and the tritium water-containing raw water can be directly supplied to the circulation tank 9 of an alkali water electrolysis device. At that time, for example as shown in FIG. 1, it is possible to have a constitution in which part of the raw water is supplied from the raw water storage tank 1 for storage to the circulation tank 9 via the raw water treatment bath 2 to which the raw water is transported as a treatment subject. The tritium water-containing raw water not containing impurities like chloride ions can be treated by the first alkali water electrolysis step by which a continuous treatment is performed in the alkali water electrolysis system (I) as shown in FIG. 1. Furthermore, even when tritium water-containing raw water containing impurities like chloride ions is used, if the treatment amount is small, the treatment time is short, the amount of impurities is small, or the constitution includes removal of the impurities during continuous electrolysis, the tritium water-containing raw water can be treated by the first embodiment. Hereinbelow, explanations are given for the case where 800,000 m3 of raw water containing only a small amount of impurities like chloride ions is treated as tritium water-containing raw water by the alkali water electrolysis system (I) with reference to FIG. 1. (a) In this embodiment, the treatment subject of the first alkali water electrolysis step is 800,000 m3 of tritium water-containing raw water which is stored in the raw water storage tank 1. As part of this raw water, raw water of 400 m3/day is supplied from the raw water storage tank 1 to the circulation tank 9 in the first alkali water electrolysis step via the raw water treatment bath 2 by means of the pump 7. Also, alkali water is supplied to the circulation tank 9 (not illustrated). Furthermore, it is preferable that the entire amount of the raw water within the raw water storage tank 1 is transported to the circulation tank 9 via the raw water treatment bath 2, and then subjected to electrolysis treatment. If the raw water within the raw water storage tank 1 is present in a large amount, it is preferable to have a constitution that the raw water is transported in several times to the raw water treatment bath 2 and the raw water within the raw water treatment bath 2 is continuously treated. The same applies to the following embodiments and examples. (b) Subsequently, within the circulation tank 9, the raw water within the circulation tank 9 is mixed with alkali water to yield an electrolyte to have desired alkali concentration. Then, the electrolyte is supplied to the alkali water electrolysis bath 8 for electrolysis treatment. (c) The alkali water of the electrolyte is preferable to have high concentration. It is preferably 15% by mass, or 20% by mass or more. Furthermore, the alkali to be used is preferably KOH or NaOH. The electrolyte within the alkali water electrolysis bath 8 is 400 m3, the amount of the electrolyte within the circulation tank 9 and pipe or the like is also 400 m3, and thus the entire electrolysis process volume is 800 m3. (d) The electrolyte mixed in the circulation tank 9 to have a desired alkali concentration is supplied to the anode chamber 16 of the alkali water electrolysis bath 8 through the circulation pipe 10 via the supply pump 12 and the cooler 14. At the same time the electrolyte is supplied to the cathode chamber 17 of the alkali water electrolysis bath 8 through the circulation pipe 11 via the supply pump 13 and the cooler 15. Then, the electrolyte is subjected to electrolysis. The electrolyte is electrolyzed as intermediated by the diaphragm 18. As a result of electrolysis, oxygen gas is generated in the anode chamber 16, and gas-liquid separation into generated oxygen gas and electrolyte is performed. The separated electrolyte is circulated to the circulation tank 9 through the electrolyte circulation pipe 10. At the same time, in the cathode chamber 17, hydrogen gas is generated, and gas-liquid separation into generated hydrogen gas and electrolyte is performed. The separated electrolyte is circulated to the circulation tank 9 through the electrolyte circulation pipe 11. By setting high current density at that time, the time required for electrolysis treatment can be shortened. The current density range for operation is affected by performance of an electrolysis bath, in particular, the anode, cathode, diaphragm and the structure of a electrolysis bath that are main factors. The current density is preferable to have 15 A/dm2 or more and 80 A/dm2 or less. More preferably, it is 20 A/dm2 or more and 60 A/dm2 or less. In particular, when the amount to be gasified by electrolysis of water is set at small volume, the process amount naturally decreases. When decomposition of a large volume is carried out, the process amount naturally increases. According to the determination by the inventors, as for the alkali water electrolysis, electrolysis can be made even with an electrolyte having alkali concentration of 32% by mass. However, when the electrolysis is carried out at a concentration higher than that, the viscosity of the electrolyte solution increases, release of generated gas to outside of the system does not occur quickly, the cell voltage becomes to have high voltage, and high energy consumption is caused. Therefore, it is not a desirable method. When the electrolysis treatment amount is 400 m3/day for the above method, the whole amount of 800,000 m3 of tritium water-containing raw water will be treated for 5.5 years (800,000 m3400 m3/day 365 days=5.5 years). Since the circulation amount of the electrolyte is 800 m3, 800,000 m3 of the tritium water-containing water is reduced to 800 m3 in 5.5 years. (e) According to the above long-term treatment, raw water in an amount corresponding to the amount of raw water lost by the electrolysis treatment is continuously supplied from the storage tank 1 to the circulation tank 9. By maintaining the alkali concentration of the electrolyte at initial concentration and continuing the electrolysis while circulating the electrolyte, the whole amount of raw water that is stored in a large amount stored in the storage tank 1 is treated by the electrolysis. (f) As a result of the treatment by the alkali water electrolysis system (I) described above, raw water containing tritium water (HTO) is gasified and converted into tritium gas (HT) containing hydrogen gas and oxygen gas. Tritium concentration in the tritium gas (HT) containing hydrogen gas is diluted to 1/1,244 compared to a case of tritium water, and the volume of the raw water of 800,000 m3 is reduced to 800 m3. According to the above continuous electrolysis mode, tritium water corresponding to the amount of water that is lost by the electrolysis is continuously supplied to the process, and the operation is performed while physical properties such as liquid amount in the electrolysis bath or discharge amount by the circulation pump of the process are always kept at constant level. At that time, the tritium water supplied to the process corresponds to the concentration of raw water. When water is continuously supplied, it is likely to have an operation in which the tritium concentration in the process is maintained at the concentration of the raw water and the tritium in the electrolysis bath is not concentrated. Under such continuous operation conditions, the gas generated by electrolysis is converted at a ration which corresponds to the concentration ratio between light water and tritium water. Hereinbelow, explanations are given for the treatment in which the initial concentration of tritium in the raw water is 6.3×106 to 4.2×106 Bq/L, and this concentration is changed to 4.2×106 Bq/L after the treatment. Namely, when the electrolysis reaction selectivity of light water and tritium water is ignored, the gas generation from light water and tritium water is based on concentration ratio of each of them. In 1 L of “treatment water”, about 55.6 moles of water molecule H2O are present, and 4.2×106 Bq/L of tritium water (HTO) are contained. Hydrogen gas conversion occurs according to this rate. The separation coefficient to be obtained is as follows. After starting the operation, when the raw water is reduced only to the circulation liquid amount (800 m3) after 5.5 years, it is as follows.Separation coefficient=Concentration of tritium contained in raw water before treatment/Concentration of tritium contained in gasified product of raw water after treatment=(4.2×106 Bq/L)/(4.2×106/1,244 Bq/L)=1,244 Meanwhile, when the effective dose coefficient is considered as the influence degree of the tritium (HT) exhibiting an influence on living organisms, it is as follows. Separation coefficient=12,440,000. As such, according to the above circulation electrolysis, a large amount of tritium water (HTO) in tritium water-containing raw water is converted to tritium gas (HT) so that the influence degree of tritium on living organisms can be significantly reduced. Namely, the tritium concentration is diluted to 1/1,244 compared to the tritium concentration in raw water before treatment. Since this concentration is 1/20 of the permissible discharge standard of tritium gas, it is taken to open air and led to high altitudes separated from any living organisms. Furthermore, when the conversion rate to tritium gas is assumed to be 40%, the amount of generated tritium gas contained in hydrogen gas is smaller so that the separation coefficient to be obtained becomes higher. In such case, the separation coefficient is as follows.Separation coefficient=Concentration of tritium contained in raw water before treatment/Concentration of tritium contained in raw fluid after treatment=(4.2×106 Bq/L/4.2×106×0.4/1,244 Bq/L=3,110. Meanwhile, when the effective dose coefficient is considered, the separation coefficient is 31,100,000. When the conversion rate to tritium gas is 40%, tritium concentration occurs based on the remaining ratio (1—conversion rate) of the tritium in the electrolysis process, but as the tritium concentration in the electrolysis process is calculated by an infinite series (Σan=A{1/(1−r)}) so that it is only 2.5 times the tritium concentration in “treatment water” than the remaining ratio r of 0.6. This makes it possible to have less exposure to radiation by tritium even when an operation is made near the process including maintenance of the electrolysis process. Such characteristic is believed to be an excellent feature as an electrolysis plant in addition to easy operation in the field. As described above, because the 1 mole of molecular gas has a volume of 22.4 L in the standard state, when 1 L (about 1000 g) of raw water is decomposed and gasified by electrolysis, content of tritium in 1 L of raw water is diluted to about 1/22.4 compared to 1 L of gas volume after gasification. Even if it is assumed that 1 L of liquid volume→about the maximum concentration, 0.4×4.2×106 Bq/L/(1,000/18×22.4 L)=1.350×103 Bq/L. It has discharge 1,000/18×22.4 L gas volume, and concentration of tritium molecule in discharged gas is lower than the concentration limit per 1 L of gas volume or air, i.e., 7×104 Bq/L. One example of the major specifications and performances of the first alkali water electrolysis step (continuous alkali water electrolysis) in the alkali water electrolysis system (I) explained above is as described below. [Specifications] 1) Raw water including tritium-contaminated water: 800,000 m3 2) Electrolysis treatment capacity: treatment amount of 400 m3/day 3) Alkali: caustic soda, alkali concentration: 20% by mass 4) Concentration of discharged tritium: 1.350×103 Bq/L 5) Alkali water electrolysis bath: 48 baths (1 bath with 75 elements) 6) Current density: 40 A/dm2 7) Electrolysis process: circulation type electrolysis process+continuous supply of raw water to electrolysis process [Performances] In general, the conversion rate of tritium in raw water is mainly dependent on the tritium concentration, but it is 1.0 to 0.6 (when fractionation is made with tritium molecular gas). When the tritium concentration contained in raw water is 4.2×106 Bq/L, the tritium concentration contained in raw fluid after treatment with the above electrolysis system is as described below. 4.2×106×0.4/1,244 Bq/L=1.350×103 Bq/L Herein, concentration limit in discharged gas or in air is 7×104 Bq/L or less, and tritium water effluent standard is 6×104 Bq/L or less. According to a second embodiment of the present invention, oxygen gas is generated in the anode chamber 16, and after being subjected to gas-liquid separation from an electrolyte, the separated oxygen gas is discharged into open air. Simultaneously, tritium gas (HT) containing hydrogen gas is generated in the cathode chamber 17. After being subjected to gas-liquid separation from an electrolyte, it is converted into tritium gas (HT) form so that the influence degree of the tritium on living organisms is reduced to 1/10,000. Namely, it can be said that the separation coefficient is 12,440,000 when the effective dose coefficient is considered. As the tritium gas from tritium water, it is taken out to open air to have 1/20 or less of the permissible discharge standard and also 0.047% or less/year of the tritium amount accumulated in the world and then led to high altitudes separated from any living organisms. According to a third embodiment of the present invention, the gasified tritium gas containing hydrogen gas can be reacted, instead of being discharged to open air, with water vapor and recovered as water containing concentrated tritium water (HTO). The reaction formula is as follows.Catalyst layer H2O (g)+HT (g)→HTO (g)+H2 (g)Absorption layer H2O (L)+HTO (g)→HTO (L)+H2O (g) FIG. 2 illustrates a fourth embodiment. The fourth embodiment relates to the alkali water electrolysis system (II) for performing batch treatment of electrolyte remained in first alkali water electrolysis step after having continuous alkali water electrolysis by the alkali water electrolysis system (I) which has been described in the above first embodiment. Specifically, according to the alkali water electrolysis system (II), the second distillation step in which the alkali component in the electrolyte which remains in the first alkali water electrolysis step is recovered as alkali salt slurry and tritium water-containing raw water distilled by the evaporator is taken out, and the second alkali water electrolysis step in which the electrolysis is performed while electrolysis capacity of an alkali water electrolysis device is adjusted to the capacity corresponding to a treatment amount of the raw water which has been taken out are performed. Furthermore, if necessary, a step in which the second distillation step and the second alkali water electrolysis step, both constituting the alkali water electrolysis system (II), are repeated several times until the completion of a batch treatment is performed. FIG. 2 is a flow chart illustrating the fourth embodiment of the alkali water electrolysis system according to the present invention consisting of the alkali water electrolysis system (II), in which the second distillation step to recover the alkali component of the electrolyte remained in the first alkali water electrolysis step of the alkali water electrolysis system (I) shown in FIG. 1 and the second alkali water electrolysis step to perform an electrolysis treatment while adjusting the electrolysis capacity of the alkali water electrolysis device to the capacity corresponding to the treatment amount of the electrolyte solution remained in the first alkali water electrolysis step are employed. In FIG. 2, when the treatment is repeated until the completion of the batch treatment as described above, the second distillation step becomes a distillation system which is used for the third, the fourth, . . . and following distillation steps. The distillation system of the second distillation step is composed of the storage tank 19 for storing the electrolyte remained in the first alkali water electrolysis step, a treatment bath 20, an evaporator 3, a slurry receiving bath 4, a small-size evaporator 5, a condenser 6, and the pump 7. Furthermore, when the treatment is repeated until the completion of a batch treatment as described above, the second alkali water electrolysis step of the alkali water electrolysis system (II) becomes an alkali water electrolysis system which is used for the third, the fourth, . . . and following alkali water electrolysis steps. The alkali water electrolysis system of the second alkali water electrolysis step is composed of the alkali water electrolysis bath 8, the circulation tank 9, the electrolyte circulation pipes 10, 11, the supply pumps 12,13, and the coolers 14, 15. The alkali water electrolysis bath 8 is composed of the anode chamber 16 for accommodating an anode, the cathode chamber 17 for accommodating a cathode, and the diaphragm 18 for separating the anode chamber 16 from the cathode chamber 17. FIG. 3 is a flow chart illustrating the process chart of the alkali water electrolysis system (II) as an embodiment carried out after treating, as tritium water-containing raw water, raw water containing only a small amount of impurities like chloride ions by the first alkali water electrolysis step in which continuous electrolysis of the alkali water electrolysis system (I) shown in FIG. 1 is performed. The alkali water electrolysis system (II) is to treat the electrolyte remained in the first alkali water electrolysis step. The alkaline water electrolysis system (II) is to perform a batch treatment of the electrolyte remained in the first alkali water electrolysis step by performing the second distillation step and the second alkali water electrolysis step shown in FIG. 2 and also by performing those treatment steps repeatedly. As shown in FIG. 3, the method for treating tritium water-containing raw water according to this embodiment includes: (i) After the first alkali water electrolysis step (continuous electrolysis of alkali water) of the alkali water electrolysis system (I) for raw water, by performing a treatment for the electrolyte remained in the first alkali water electrolysis step, the treatment is carried out by the alkali water electrolysis system (II) consisting of each step shown below;(ii) The second distillation step for the electrolyte remained in the first alkali water electrolysis step (separation and recovery of the first alkali salt slurry);(iii) The second alkali water electrolysis step for tritium water-containing water obtained in the second distillation step;(iv) The third distillation step for the electrolyte remained in the second alkali water electrolysis step (separation and recovery of the second alkali salt slurry);(v) The third alkali water electrolysis step for tritium water-containing water obtained in the third distillation step;(vi) The fourth distillation step for the electrolyte remained in the third alkali water electrolysis step (separation and recovery of the third alkali salt slurry);(vii) The fourth alkali water electrolysis step obtained in the fourth distillation step; and(viii) The fifth distillation step for the electrolyte remained in the third alkali water electrolysis step (separation and recovery of the fourth alkali salt slurry). For each distillation step described above, a distillation system consisting of the second distillation step shown in FIG. 2 was used. For each of the above alkali water electrolysis step, an alkali water electrolysis system consisting of the second alkali water electrolysis step shown in FIG. 2 was used, although the electrolysis capacity gradually decreases. Hereinbelow, by having a treatment of 800,000 m3 of tritium water-containing raw water as large-volume raw water containing tritium water, which contains only a small amount of impurities like chloride ions, as an example, each step for carrying out the treatment according to the process chart shown in FIG. 3 is explained in detail. (i) First Alkali Water Electrolysis Step According to this embodiment, regarding the first alkali water electrolysis step, 800,000 m3 of tritium water-containing raw water stored in the raw water storage tank 1, in which only a small amount of impurities like chloride ions is contained, is first reduced to 800 m3 by the method described in the above first embodiment with the alkali water electrolysis system (I) shown in FIG. 1. (ii) Second Distillation Step Next, after the completion of the first alkali water electrolysis step of the alkali water electrolysis system (I), the total amount of 800 m3 of the electrolyte solution remained in the first alkali water electrolysis step is treated as follows by the alkali water electrolysis system (II) shown in FIG. 2. The electrolyte remained in the first alkali water electrolysis step is supplied to the evaporator 3 of the distillation system via the treatment bath 20. The tritium water-containing water distilled by the evaporator 3 is condensed by the condenser 6, and is taken out. The tritium water-containing water is supplied to circulation tank 9 of the alkali water electrolysis system (II) by means of the pump 7. In addition, the alkali water in the electrolyte remained in the first alkali water electrolysis step is taken out as alkali salt slurry by the slurry receiving bath 4. The resulting slurry is sent to the small-size evaporator 5, and by performing evaporation, crystallization/drying and the like, it is separated and recovered as a solid matter. Further evaporation, crystallization/drying of the salt slurry according to this process is an operation for reducing the volume as described below. In addition, as the wastes are solidified, the probability of having corrosive damage of a container for storing the wastes is particularly lowered compared to liquid. Performing solidification under this object is highly meaningful in terms of waste storage of radioactive substances. As described above, the remaining liquid amount of the electrolyte after completion of the first alkali water electrolysis step in the alkali water electrolysis system (I) is 800 m3. As the alkali concentration is 20% by mass, the alkali salt slurry recovered in the alkali water electrolysis system (II) is 160 m3 (about 160 tons). The recovered salt slurry is sent to the small-size evaporator 5. After evaporation, crystallization/drying and the like, it is concentrated and then separated and recovered as a solid matter. (iii) Second Alkali Water Electrolysis Step The electrolyte taken out by the second distillation step and continuously supplied to the circulation tank 9 for a treatment by the second alkali water electrolysis step consists only of tritium water-containing water with an amount of 640 m3, from which 160 m3 of the alkali salt slurry is recovered and removed. In the second alkali water electrolysis step, new alkali water is supplied to the circulation tank 9, and by mixing the tritium water-containing water and newly added alkali water in the circulation tank 9, about 800 m3 of electrolyte is prepared and supplied to the alkali water electrolysis device 8. With regard to the alkali water electrolysis device 8 used for electrolysis of the second alkali water electrolysis step, for the initial treatment, the electrolysis treatment is carried out by using the very bath number used for the first alkali water electrolysis step, for example, 48 baths (75 element for 1 bath) for the above example. As for the alkali water, 5% by mass or so of alkali water electrolyte was prepared first. The current density is set at 20 A/dm2. It is the same for the following third and fourth alkali water electrolysis step. In the second alkali water electrolysis step of the alkali water electrolysis system (II), unlike the first alkali water electrolysis step, there is no additional supply of raw water and tritium water-containing water is decomposed and removed. As such, alkali water is concentrated simultaneously with a decrease in the amount of the electrolyte. Thus, an operation is performed with less operating lines of an electrolysis bath by controlling a process valve. When the electrolyte is concentrated by 6 times, the alkali concentration is from 5% by mass to 30% by mass so that the electrolysis bath is controlled to have 8-bath operation (75 elements for 1 bath). Namely, according to the second alkali water electrolysis step, the electrolysis is performed until about 800 m3 of the electrolyte is concentrated by 6 times and the alkali concentration is 30% by mass and the electrolysis bath is controlled to have 8-bath operation (75 elements for 1 bath). As a result of this treatment, 800 m3 of the electrolyte is reduced to 133 m3. Furthermore, operation of the second alkali water electrolysis step is carried out in the same manner as the above-mentioned first alkali water electrolysis step. [Repeating Step] In the repeating step consisting of the second distillation step and the second alkali water electrolysis step for constituting the alkali water electrolysis system (II), the treatment is further repeated while reducing gradually the capacity of the alkali water electrolysis device. By gasifying tritium water (HTO) in the tritium water-containing water, tritium water (HTO) is converted to tritium gas (HT), and also volume of the tritium water-containing water is further reduced. Specific explanations are given hereinbelow. (iv) Third Distillation Step (Second Separation and Recovery of Alkali Slurry) According to the third distillation step following the second alkali water electrolysis step, the alkali salt slurry (133 m3×30% by mass=40 m3) is recovered and separated. For reducing the volume, the alkali salt slurry may be further sent to the small-size evaporator 5 followed by evaporation, crystallization/drying and the like, and then it can be used again. (v) Third Alkali Water Electrolysis Step The electrolysis treatment of tritium water-containing water obtained by the third distillation step is carried out in the same manner as the second alkali water electrolysis step except that capacity of the alkali water electrolysis device is reduced. Namely, according to the third alkali water electrolysis step, 8 baths of the alkali water electrolysis bath 8 are used to start the electrolysis, and an operation is performed with less operating lines of an electrolysis bath until the electrolyte solution of 4 times is yielded by controlling a process valve. Then, when the electrolyte is concentrated by 4 times, the alkali concentration increases from 5% by mass to 20% by mass so that the electrolysis bath is controlled to have 2-bath operation. As a result of this treatment, 133 m3 of the electrolyte is reduced to 22.17 m3. (vi) Fourth Distillation Step and (vii) Fourth Alkali Water Electrolysis Step Subsequently, in the same manner as the third case, alkali salt (22.17 m3×20% by mass=4.4 m3) was separated and recovered by the fourth distillation step. The electrolysis treatment of the tritium water-containing water obtained from the fourth distillation step is performed in the same manner as the second alkali water electrolysis step except that capacity of the alkali water electrolysis device is reduced. Namely, the alkali water electrolysis device 8 is operated after modifying 1 bath with 75 elements to 1 bath with 8 elements, and after performing the fourth alkali water electrolysis step, 5% by mass caustic alkali was added to prepare the electrolyte at 23 m3. As a result of this treatment, the electrolyte was concentrated by 19.17 times (23÷1.2=19.17) and the volume was reduced from 23 m3 to 1.2 m3. (viii) Fifth Distillation Step Finally, the caustic property of the obtained alkali water electrolyte in an amount of about 1.2 m3 was separated and removed with the evaporator 3 during the fifth distillation step. As a result, distilled water containing about 1 m3 of tritium is obtained. The operations following the second alkali water electrolysis step can be completed by an operation for 1 month or so, even if a sufficient operation interval is applied. Furthermore, 1 m3 of tritium water, which is finally obtained, can be almost completely converted into tritium gas by electrolysis if the same treatment is repeated with a smaller electrolysis device. Namely, the amount of tritium water waste can be reduced to almost zero. For the repeating operation of the repeating step, 32% by mass was set as an upper limit of actual plant operation. However, the operation can be made as high as 40 to 50% by mass. For example, when light hydrogen and tritium gas that are simultaneously generated are discharged, without having any particular fractional process, to the outside of the process via water seal system, conversion rate of the tritium gas changes delicately in view of the relationship between the decrease in the electrolyte and the increase in alkali concentration. However, by confirming the conversion rate over time based on initial conversion rate relative to concentration change of 10 times and the change rate at final concentration, the conversion rate of the tritium gas at each state is obtained. One example is shown below. For example, when treatment water of 1 L (55.6 moles of water) is electrolyzed in batch mode until the alkali is concentrated by 10 times (i.e., 1 L→0.1 L), hydrogen gas generated at the cathode has a volume which is increased by 1,120 times (55.6×0.9×22.4 L) in the standard state. This means that the tritium is diluted by the gas generated at cathode. Thus, with such dilution ratio, 4.2×106 Bq/L of tritium contained in raw water may yield by itself tritium concentration of 3.37×103 Bq/L (=4.2×106 Bq/L×0.9/1,120), and it is a concentration which is less than 1/20 of the permissible discharge standard of tritium gas.Separation coefficient=Concentration of tritium contained “treatment water” before treatment/Concentration of tritium contained in “treatment gas” after treatment=(4.2×106 Bq/L/4.2×106/1,120 Bq/L=1,120 Meanwhile, because conversion is made from tritium water (HTO) form to tritium gas (HT) form, and the dose coefficient as radiation indicator exhibiting an influence on living organisms is 1/10,000, the separation coefficient considering the effective dose coefficient is as follows. Separation coefficient=11,200,000. For shortening the period required for volume reduction, the period can be relatively shortened in proportion to an increase in current density. Meanwhile, considering the power consumption amount of the process and stable and safe operation, there is naturally a limit for having high current density. For the alkali water electrolysis, about 60 A/dm2 is an upper region at present moment. With regard to tritium water-containing water according to a fifth embodiment, a method for treating a large amount of raw water containing tritium water which contains a large amount of impurities like chloride ions is shown. As shown in FIG. 4, as a pre-step before the first alkali water electrolysis step (continuous alkali electrolysis) of the above-mentioned alkali water electrolysis system (I), the first distillation step (removal of salt slurry) is performed. In FIG. 4, the distillation system used for the first distillation step is shown at the upper left corner, and the alkali water electrolysis system (I) to perform the first alkali water electrolysis step is shown at the upper right corner. As shown in FIG. 4, the fifth embodiment is the same as the aforementioned first embodiment except that the distillation step is provided as a pre-step for removing a large amount of impurities from raw water before the first alkali water electrolysis step. Since the details of the first distillation step are the same as the sixth embodiment, explanations will be given later. Like the fifth embodiment, a sixth embodiment includes performing the first distillation step (removal of salt slurry) as a pre-step before the first alkali water electrolysis step (continuous electrolysis of alkali water) of the above-mentioned alkali water electrolysis system (I), and after the first alkali water electrolysis step as a pre-step (I), performing repeatedly the second distillation step and the second alkali water electrolysis step which constitute the alkali water electrolysis system (II) shown in FIG. 2 which is explained in the fourth embodiment for a batch treatment of the electrolyte remained in the first alkali water electrolysis step. Specifically, the sixth embodiment consists of each of the following steps as shown in FIG. 5, i.e., (0) the first distillation step (removal of salt slurry) as a pre-step, (i) (I) the first alkali water electrolysis step (continuous electrolysis of alkali water) for raw water from which impurities have been removed, (ii) the second distillation step (separation and recovery of the first alkali salt slurry) for the electrolyte remained in the first alkali water electrolysis step as the alkali water electrolysis system (I), (iii) the second alkali water electrolysis step for tritium water-containing water obtained from the second distillation step, (iv) the third distillation step (separation and recovery of the second alkali salt slurry) for the electrolyte remained in the second alkali water electrolysis step as the alkali water electrolysis system (II), (v) the third alkali water electrolysis step for tritium water-containing water obtained from the third distillation step, (vi) the fourth distillation step (separation and recovery of the third alkali salt slurry) for the electrolyte remained in the third alkali water electrolysis step, (vii) the fourth alkali water electrolysis step obtained from the fourth distillation step, and (viii) the fifth distillation step (separation and recovery of the fourth alkali salt slurry) for the electrolyte remained in the fourth alkali water electrolysis step. Hereinbelow, the embodiment 6 is explained as an example for treating 800,000 m3 of tritium water-containing raw water as a large amount of raw water containing tritium water which contains a great amount of impurities like chloride ions. FIG. 4 is a flow chart illustrating the sixth embodiment of the alkali water electrolysis system according to the present invention, which is used for, when raw water containing a large amount of impurities like chloride ions is used as tritium water-containing raw water, the first distillation step as a pre-step of electrolysis carried out for removing the impurities, the first alkali water electrolysis step as the alkali water electrolysis system (I) in which continuous electrolysis is performed while maintaining constant alkali concentration, the second distillation in which, as the alkali water electrolysis system (II), the alkali component of the electrolyte solution remained in the first alkali water electrolysis step is recovered, and the second alkali water electrolysis step to have an electrolysis treatment while adjusting the electrolysis capacity of the alkali water electrolysis device to the capacity corresponding to the treatment amount of the electrolyte solution remained in the first alkali water electrolysis step. Furthermore, FIG. 5 is a flow chart illustrating the sixth embodiment as a treatment method for treating raw water containing a large amount of impurities like chloride ions as tritium water-containing raw water as described above. (0) First Distillation Step as Pre-Step When raw water containing a great amount of impurities like chloride ions is treated, a large amount of raw water including contaminated water which contains tritium water is supplied from the raw water storage tank 1 to the first distillation step via the raw water treatment bath 2 as shown in FIG. 4. The raw water supplied to the raw water treatment bath 2 is sent to the evaporator 3. Then, salt slurry including all the impurities like salts, calcium, magnesium, and other radioactive nuclear species, which are contained in raw water, are collectively stored in the slurry receiving bath 4. The salt slurry can be stored for a long period of time in Ti tank. However, as the Ti material is expensive, it is also possible to store the salt slurry with a material in which rubber lining is applied to an inexpensive stainless base. The salt slurry is sent to the small-size evaporator 5, and for the purpose of further reducing the volume, it is preferable to perform concentration and semi solidification of slurry by carrying out evaporation, crystallization/drying. Furthermore, it is constituted such that tritium water-containing water evaporated from the small-size evaporator 5 is condensed in the condenser 6 together with tritium water-containing water evaporated from the evaporator 3 used for obtaining the above salt slurry, and then supplied to the circulation tank 9 by means of the pump 7. Meanwhile, it is necessary that the slurry containing radioactive materials is handled by manless operation as much as possible regarding obtainment of solid salt containing radioactive materials, storage of the solid salt, maintenance of a device and apparatus for concentration, and the like. For example, the solid salt containing radioactive materials is stored in a stainless container with rubber lining which has no problem in terms of long-term resistance to corrosion. As described below, the corrosion property is significantly lowered, and the effect of having remarkable volume reduction is huge by semi-solidification of salt. For example, when impurities are removed by treating contaminated water which contains 800,000 m3 of tritium water as raw water, if a treatment bath having process capacity of 400 m3/day is used as the raw water treatment bath 2, the salt slurry obtained by a treatment of the first distillation step as a pre-step will have a volume of 40 m3 so that a state having 10 times condensation than the salt slurry is obtained. By the first distillation step, the waste as impurities from 400 m3/day can be discarded as solid salt of about 8 m3/day. As such, compared to 800,000 m3 of contaminated water containing tritium water, volume of the waste as impurities is reduced to 16,000 m3 of a solid salt waste (1/50 reduction). This means that, although no tritium is present in the solid salt waste, if a radioactive material like a trace amount of Co is present, such radioactive material is also concentrated by 50 times compared to the original concentration. (i) First Alkali Water Electrolysis Step (Continuous Alkali Electrolysis) as Alkali Water Electrolysis System (I) As described above, according to the sixth embodiment (and also for the fifth embodiment), the salt slurry removed from raw water treated at 400 m3/day is 40 m3/day, and tritium water-containing raw water excluding the impurities that are removed as this salt slurry is condensed by the condenser 5. The raw water is supplied to the circulation tank 9 of an alkali water electrolysis system which is used for the first alkali water electrolysis step as a next step at 360 m3/day by means of the pump 7. As described before, when the salt slurry is distilled and crystallized by the small-size evaporator 5 and then distilled water and tritium water are recovered from the salt slurry, tritium water-containing water condensed by the condenser 6 is 392 m3/day. According to the sixth embodiment (and also for the fifth embodiment), tritium water-containing water is supplied to the circulation tank 9 of the first alkali water electrolysis step at 360 m3/day to 392 m3/day by means of the pump 7. At the same time, alkali water is supplied and mixed therein so that the electrolyte at 400 m3/day is adjusted to alkali concentration of 20% by mass. The electrolyte in the alkali water electrolysis bath 8 is 400 m3, and the amount of the electrolyte in the circulation tank 9, pipe, or the like is 400 m3. Thus the entire electrolysis process capacity is 800 m3. The electrolyte controlled to have alkali concentration of 20% by mass according to mixing in the circulation tank 9 is supplied to the anode chamber 16 of the alkali water electrolysis bath 8 via the circulation pipe 10 by means of the supply pump 13 and the cooler 14. In the same manner, supplied to the cathode chamber 17 of the alkali water electrolysis bath 8 via the circulation pipe 11 by means of the supply pump 13 and the cooler 15. The electrolyte prepared as alkali water with desired concentration is supplied at 400 m3/day to the inside of the alkali water electrolysis bath 8 for electrolysis. The electrolyte is electrolyzed by a diaphragm. In the anode chamber 16, oxygen gas is generated. The generated oxygen and the electrolyte are separated. The separated electrolyte is circulated to the circulation tank 9 via the electrolyte circulation pipe 10. At the same time, in the cathode chamber 17, hydrogen gas is generated. The generated hydrogen and the electrolyte are separated. The separated electrolyte is circulated to the circulation tank 9 via the electrolyte circulation pipe 11. By setting high current density at that time, time required for the electrolysis treatment can be shortened. The current density is preferably 20 A/dm3 or more and 60 A/dm3 less. The circulation liquid amount of the electrolyte solution is 800 m3 for this entire electrolysis process. This amount is simply based on the process design, and the present invention is not limited to it. In particular, if the amount to be gasified by electrolysis of water is designed to be small, the process amount is also small. On the other hand, if large scale decomposition is carried out, the process amount generally increases. With regard to the alkali water electrolysis, electrolysis is possible even at the concentration of 32% by mass. However, when the electrolysis is carried out at a concentration higher than that, the viscosity of the electrolyte solution increases, release of generated gas to outside of the system does not occur quickly, the cell voltage becomes to have high voltage, and high energy consumption is caused, and therefore it is not a desirable method. Thus, the continuous electrolysis is terminated at this moment, and for the purpose of decomposition of electrolyte to alkali and water, the electrolyte remained in the first alkali water electrolysis step as the alkali water electrolysis system (I) is transferred to the second distillation step, the second alkali water electrolysis step, and the final volume decreasing step as the alkali water electrolysis system (II), as described above for the fourth embodiment. When the electrolysis treatment amount is 400 m3/day, the whole amount of 800,000 m3 of raw water including contaminated water containing tritium water will be treated for 5.5 years (800,000 m3÷400 m3/day 365 days=5.5 years). Furthermore, the circulation amount of the electrolyte at that time is 800 m3, and 800,000 m3 of the tritium water-containing water will be reduced to 800 m3 in 5.5 years. According to the fifth and the sixth embodiments, impurities in a large amount of raw water containing tritium water, which contains impurities like chloride ions, are removed as salt slurry by the method shown in FIG. 4, and the electrolysis performed at the first alkali water electrolysis step to decompose the raw water into oxygen and hydrogen. Thereby, the tritium present as water molecule in the raw water is converted to a tritium molecule and fractionated from the raw water. As shown in FIGS. 4 and 5, in the sixth embodiment, after completion of the first alkali water electrolysis step, the whole amount of the electrolyte remained in the first alkali water electrolysis step is supplied to the evaporator 3 of a distillation system like the aforementioned fourth embodiment, and treated similarly via the following steps, i.e., (ii) as the alkali water electrolysis system (II), the second distillation step (separation and recovery of the first alkali salt slurry) for the electrolyte remained in the first alkali water electrolysis step, (iii) the second alkali water electrolysis step for tritium water-containing water obtained in the second distillation step, (iv) the third distillation step (separation and recovery of the second alkali salt slurry) for the electrolyte remained in the second alkali water electrolysis step, (v) the third alkali water electrolysis step for tritium water-containing water obtained in the third distillation step, (vi) the fourth distillation step (separation and recovery of the third alkali salt slurry) for the electrolyte remained in the third alkali water electrolysis step, (vii) the fourth alkali water electrolysis step obtained in the fourth distillation step, and (viii) the fifth distillation step (separation and recovery of the fourth alkali salt slurry) for the electrolyte remained in the fourth alkali water electrolysis step. Volume of the electrolyte remained after the fourth alkali water electrolysis step is reduced to 1.2 m3. During the fifth distillation step, the finally obtained alkali water electrolyte in an amount of about 1.2 m3 is separated and removed as alkali salt slurry by the evaporator 3 to be recovered, and at the same time, distilled water containing tritium in an amount of 1 m3 is obtained. The operations following the second alkali water electrolysis step can be completed by an operation for 1 month or so, even when a sufficient operation interval is applied. 1 m3 of the tritium water can be almost completely converted into tritium gas by electrolysis if the same treatment is repeated with a smaller electrolysis device. Namely, the amount of tritium water waste can be reduced to almost zero. Furthermore, according to the above sixth embodiment, as for the facilities for the distillation steps of the second, the third, and the following steps, the facilities used for the first distillation step as a pre-step for removing impurities like a large amount of chloride ions in the tritium water-containing water can be also used, and thus significant saving of facility can be achieved. Next, the examples of the present invention are explained, but the present invention is not limited to those examples. As simulated liquid of tritium water-containing raw water not containing impurities (hereinbelow, referred to as simulated liquid), the simulated liquid with the following components was used. Simulated liquid: 180 L Initial concentration of tritium in the simulated liquid: 4.2×106 Bq/L As shown in FIG. 1, the raw water storage tank 1 added with 180 L of the simulated liquid was prepared. In the present test, the liquid was supplied from the raw water storage tank 1 to the circulation tank 9 via the treatment bath 2. Specifically, the simulated liquid was supplied at 9.67 L/day from the raw water storage tank 1 to the circulation tank 9 via the treatment bath 2 by means of the pump 7. In the present test, electrolyte including the simulated liquid was continuously supplied in the first alkali water electrolysis step, and continuous electrolysis was performed while circulating the electrolyte. Specifically, to the circulation tank 9, the simulated liquid is supplied at 9.60 L/day by means of the pump 7, and at the same time, alkali water is supplied and mixed to give an electrolyte of 9.67 L/day of which alkali concentration is adjusted to 20% by mass, and continuous electrolysis was performed while circulating this electrolyte. The electrolyte in the alkali water electrolysis bath 8 is 30 L (2 cells of 15 dm2 cell (15 L)), and the amount of the electrolyte in the circulation tank 9, pipe, or the like is 12 L. Thus, the entire electrolysis process volume is 42 L. The electrolyte of which alkali concentration is controlled to 20% by mass, as obtained by mixing alkali in the circulation tank 9, was supplied to the anode chamber 16 of the alkali water electrolysis bath 8 through the circulation pipe 10 via the supply pump 13 and the cooler 14. At the same time, the electrolyte is supplied to cathode chamber 17 of the alkali water electrolysis bath 8 through the circulation pipe 11 via the supply pump 13 and the cooler 15. The electrolyte adjusted to have concentration of 20% by mass of alkali water is electrolyzed as intermediated by a diaphragm. Oxygen gas is generated from the anode chamber 16, and gas-liquid separation into generated oxygen gas and electrolyte is performed. The separated electrolyte is circulated to the circulation tank 9 through the electrolyte circulation pipe 10. At the same, hydrogen gas is generated inside the cathode chamber 17, and gas-liquid separation into generated hydrogen gas and electrolyte is performed. The separated electrolyte is circulated to the circulation tank 9 through the electrolyte circulation pipe 11. As described above, in this example, simulated liquid as raw water was electrolyzed by the alkali water electrolysis according to the method shown in FIG. 1 so that the raw water is decomposed into oxygen and hydrogen. Thereby tritium present as water molecule in the raw water is fractionated as tritium molecule from the raw water. Water was decomposed by electrolysis only into hydrogen and oxygen gas. Thus, after adjusting the initial alkali concentration, electrolysis was performed while raw water (simulated water) in an amount corresponding to the water lost by electrolysis is supplied to the circulating electrolyte. Furthermore, if necessary, distilled water or pure water may be added to the raw water to maintain the alkali concentration at the initial concentration. In the present example, continuous alkali electrolysis in the first alkali water electrolysis step was carried out according to the following conditions. Electrolysis cell: 2 cells (30 L) of 15 dm2 cell (15 L) were used. Current density for operation: 40 A/dm2 Caustic concentration: NaOH, 20% by mass Membrane: diaphragm Anode/cathode: Ni base+active coating Circulation: External circulating system Water seal: water seal system to control gas pressure 50-100 mm H2O cathode pressure Volume of electrolyte: 42 L (electrolysis cell: 15×2=30 L, circulation pipe or the like: 12 L) Electrolysis current was 600 A (15 dm2×40 A/dm2). According to continuous electrolysis, as described above, the operation is made while raw water (simulated water) in an amount corresponding to the water decomposed and lost by electrolysis is supplied continuously to the process and a physical environment of operations such as liquid amount in an electrolysis bath or discharge amount by a circulation pump is maintained at constant level during the process. When the raw water is continuously supplied, the operation is made such that tritium concentration in the process is maintained at the concentration of simulated liquid while the tritium inside the electrolysis bath is not concentrated. As such, according to the conditions of this continuous operation, gas generated by the electrolysis is converted to the ratio which corresponds to the concentration ratio between light water and tritium water. The circulation amount of electrolysis at that time was 42 L, and 180 L of tritium water-containing water was reduced to 42 L during 15.2 days (365 hours). When continuous operation is made for 15.2 days (365 hours) after starting the operation, tritium removal is described as follows.Separation coefficient=Concentration of tritium contained raw water before treatment/Concentration of tritium contained in raw material gasification after treatment=(4.2×106 Bq/L)/(4.2×106/1,244 Bq/L)=1,244 Meanwhile, when the effective dose coefficient is considered as the influence degree of the tritium (HT) exhibiting an influence on living organisms, it is as follows. Separation coefficient=12,440,000. Thus, as tritium water (HTO) in the large volume of tritium water-containing water is converted to tritium gas (HT), the tritium concentration is diluted to 1/1,244 and the tritium's influence on living organisms is significantly lowered. Diluted tritium gas was taken out to open air in an amount of 1/20 of the permissible discharge standard, and led to high altitudes separated from any living organisms. The gasified tritium gas containing hydrogen gas was reacted with water vapor instead of discharge to open air. Accordingly, it was recovered as tritium water (HTO) containing water. The reaction formula is as described below.Catalyst layer H2O (g)+HT (g)→HTO (g)+H2 (g)Absorption layer H2O (L)+HTO (g)→HTO (L)+H2O (g) (i) First Alkali Water Electrolysis Step (Continuous Alkali Electrolysis) Continuous electrolysis was performed in the same manner as Example 1, and 180 L of tritium water-containing water as simulated liquid was reduced to 42 L for 15.2 days (365 hours). (ii) Second Distillation Step After completion of the first alkali water electrolysis step, as shown in FIGS. 2 and 3, the whole amount of the electrolyte remained in the first alkali water electrolysis step was supplied to the evaporator 3 of a distillation system, and tritium water-containing water distilled by the evaporator 3 was condensed by the condenser 6. After taking out the water, it was supplied to the circulation tank 9 of an alkali water electrolysis system by means of the pump 7. Also, the alkali water in the electrolyte remained in the first alkali water electrolysis step was recovered as alkali caustic salt slurry from the slurry receiving bath 4. Further, for reducing the volume, the slurry was sent to the small-size evaporator 5 and subjected to evaporation, crystallization/drying and the like to have concentration and semi solidification of slurry. As described above, the liquid amount of the electrolyte is 42 L, and the alkali concentration is 20% by mass. Thus, the alkali caustic salt slurry recovered in the second distillation step is 8.4 L. The recovered caustic salt slurry was concentrated and then separated as a solid matter. Further, for reducing the volume, it was sent to the small-size evaporator 5 for evaporation, crystallization/drying. Accordingly, about 5 L (specific gravity of 2.13) of 10.5 Kg (10.5/(42+10.5)×100=20% by mass) of a solidified alkali in an amount which corresponds to the amount of the alkali prepared before the electrolysis can be recovered. (iii) Second Alkali Water Electrolysis Step The electrolyte taken out in the second distillation step and supplied to the circulation tank 9 is recovered and removed as 8.4 L of alkali caustic salt slurry, and it contains just tritium water-containing water. The amount of the tritium water-containing water is 42−8.4=33.6 L. While this tritium water is supplied to the circulation tank 9, fresh alkali water is added to the circulation tank 9. The electrolyte in which tritium water-containing water is mixed with alkali water was adjusted to 42 L in the circulation tank 9, and the adjusted electrolyte was supplied to the alkali water electrolysis device 8. The alkali water electrolysis device 8 used for the electrolysis is first used with the same capacity as the capacity used for the first alkali water electrolysis step and then the electrolysis was carried out. As for the alkali water, about 5% by mass of alkali water electrolyte was prepared first. The current density was 20 A/dm2, and it remains the same for the following third and fourth alkali water electrolysis steps. For the second alkali water electrolysis step of the alkali water electrolysis system (II), since further addition of raw water was not made and water in the raw water (simulated liquid) is decomposed and removed, the electrolyte amount was reduced and at the same time the alkali water was concentrated. Thus, by controlling a process valve, an operation was performed with less operating lines of an electrolysis bath. When the electrolyte is concentrated by 5.25 times, the alkali concentration was from 5% by mass to 26.25% by mass so that volume of the electrolyte (42 L) was reduced as follows: 42/5.25=8 L. Operation of the second alkali water electrolysis step was performed in the same manner as the first alkali water electrolysis step. (iv) Third Distillation Step, Repeating Step. According to the repeating step, the second distillation step and the second alkali water electrolysis step were repeated while reducing gradually the capacity of the alkali water electrolysis device so that tritium water (HTO) in the raw water is gasified and converted into tritium gas (HT) and volume of the tritium water-containing water is further reduced. After the second alkali water electrolysis step, the alkali caustic salt slurry was recovered and separated by the third distillation step. For further reducing the volume, the alkali caustic salt slurry was sent to the small-size evaporator 5 and subjected to evaporation, crystallization/drying, and then recovered as a solid alkali. After that, according to the third alkali water electrolysis step, the electrolysis was initiated with 8 L using the electrolyte in the alkali water electrolysis bath 8. The test was carried out while reducing the number of elements until the electrolyte is concentrated by 4 times. Since the alkali concentration was from 5% by mass to 20% by mass, the electrolysis bath was controlled to have an operation of 2 L. As a result of the treatment, 8 L volume of the electrolysis was reduced to 2 L. The operations following the second alkali water electrolysis step can be completed by an operation for 1 month or so even if a sufficient operation interval is considered, although the influence of operation current density is significant. (0) First Distillation Step as Pre-Step As simulated liquid of raw water including contaminated water containing tritium water which contains a large amount of impurities, the simulated liquid with the following components was used. Simulated liquid: 180 L Initial concentration of tritium in raw water: 4.2×106 Bq/L Components and concentration of impurities: Table salt: 10 g/L Calcium: 2 ppm Magnesium: 5 ppm As shown in the upper panel of FIG. 4, 180 L of the simulated liquid was supplied from the raw water storage tank 1 to the raw water treatment bath 20. As the raw water treatment bath 20, a treatment bath having treatment capacity of 9.67 L/day was used. The simulated liquid supplied to the raw water treatment bath 20 was sent to the evaporator 3, and impurities like salts, calcium, and magnesium in the simulated liquid were collectively removed as 18 L of salt slurry. Meanwhile, 18 L of the salt slurry was sent to the small-size evaporator 5 and subjected to evaporation, crystallization/drying for further reducing of the volume. Accordingly, concentration and semi solidification of the slurry was performed to give 0.9 L of a solidified salt. Thus, 180 L of the simulated liquid was turned out to be reduced to 0.9 L of solid salt waste as the waste of impurities. The tritium water-containing water evaporated from the small-size evaporator 5 for raw water was condensed by the condenser 6 together with tritium water-containing water evaporated by the evaporator 3, and supplied to the circulation tank 9 via the pump 7. The tritium water-containing water was at 9.60 L/day. (i) First Alkali Water Electrolysis Step as Alkali Water Electrolysis System (I) The tritium water-containing water at 9.60 L/day as treated above was supplied to the circulation tank 9 of an alkali water electrolysis system which is used for the first alkali water electrolysis step as a following step via the pump 7. According to the first alkali water electrolysis step, the tritium water-containing water was continuously supplied by the method described in Example 1 so that the electrolyte is electrolyzed under circulation. After completion of the (i) the first alkali water electrolysis step, (ii) the second distillation step, (iii) the second alkali water electrolysis step, and also the repeating step were carried out in the same manner as the method described in Example 4, as shown in FIGS. 4 and 5. According to the present invention, by gasifying tritium water (HTO) in tritium water-containing water for conversion to tritium gas (HT) and oxygen gas and by diluting the tritium concentration to 1/1,244, the influence degree of the tritium on a living organism can be particularly reduced, so that the tritium can be led to high altitudes separated from any living organisms. It is also possible that the gasified tritium gas containing hydrogen gas is reacted with water vapor and recovered as tritium water (HTO) containing water. Furthermore, according to the present invention, even for tritium water-containing raw water which contains a large amount of impurities like chloride ions, continuous electrolysis can be made by removing in advance the impurities in raw water as salt slurry, and thus the aforementioned effect is also obtained. Furthermore, because the impurities in raw water can be recovered as alkali salt slurry, it can be realized also considering an area of a plant and cost involved with construction and running the plant, and thus the industrial contributiveness is very high. 1: Raw water storage tank 2: Raw water treatment bath 3: Evaporator 4: Slurry receiving bath 5: Small-size evaporator 6: Condenser 7: Pump 8: Alkali water electrolysis bath 9: Circulation tank 10, 11: Electrolyte circulation pipe 12, 13: Supply pump 14, 15: Cooler 16: Anode chamber for accommodating anode 17: Cathode chamber for accommodating cathode 18: Diaphragm for separating anode chamber 16 from cathode chamber 17 19: Storage tank for storing electrolyte remained in first alkali water electrolysis step 20: Treatment bath
	description	This U.S. non-provisional patent application claims the benefit of and/or priority under 35 U.S.C. § 119(e) to U.S. provisional patent application Ser. No. 62/380,086 filed Aug. 26, 2016 titled “Device and Method for the Heating and Confinement of Plasma,” the entire contents of which is specifically incorporated herein by reference. The present invention relates in general to the subjects of ionized gas (plasma) devices, and devices and methods for plasma heating and specifically, to devices and methods for plasma heating and current drive in magnetic confinement devices possessing cusp-shaped magnetic fields. A certain class of open magnetic field topologies is generally suited for stable plasma confinement, namely cusps, however cusp confinement introduces its own challenges. Primary among these is the challenge of minimizing particle loss out through the cusp, but also practical challenges exist related to impurities, high-voltage breakdown, plasma heating, and methods to drive plasma currents. Minimizing impurity buildup is generally necessary for generating and maintaining high plasma temperatures in low-atomic number plasmas of, for example, deuterium and tritium, and generally impurities form when hot dense plasma impinges on vessel structures such as antennae [Cairns 1991 pg. 42] and support structures [Dolan 1994]. High voltage breakdown can occur on these same elements when high voltages (thousands or millions of volts) across the confinement field are applied for, for example, cusp “plugging” by electrostatic fields [Dolan 1994], or rotation [Abdrashitov 1991]. Another challenge of high-energy plasma physics is plasma heating. Numerous methods exist to heat plasma such as neutral beam injection, electron beam injection, and microwaves. Alternatively radio-frequency resonance, for example ion cyclotron resonance heating (ICRH), comprises effective means for heating plasma to high temperatures such as those required for nuclear fusion and other uses [Cairns 1991]. Finally, it is generally favorable to be able to apply currents to the plasma and generally the means of doing so are related to heating means and thus heating and current drive are closely related [Cairns 1991]. It would be beneficial to those skilled in the art of cusped plasma confinement to have a means of supporting the field coils in such a way as to reduce exposure of the support to hot dense plasma for reducing impurity buildup and improving voltage holding, and that could additionally incorporate heating or current driving schemes. Cusp reactors, for example linear sets of multiple ring cusps such as the Jupiter series of reactors [Dolan 1994], have the benefit of good magnetohydrodynamic stability. Cusp reactors also have the benefit of being amenable to means of direct energy conversion by means of particle transport radially through open cusps into outboard regions containing electrostatic deceleration electrodes or other means [Miley 1976]. In this case coil support placement is important. Placement of the coil support through the field coil places it in contact with hot dense plasma in the cusp region between adjacent field coils. This provides a surface for ablation of coil support surface material into the plasma and introduction of high-Z impurities as well as a surface for high-voltage breakdown of potentials applied across field lines. Coating the support with low-Z materials such as Beryllium or other compounds is one present means for reducing plasma degradation by impurities [Cairns 1991 p. 42]. Disclosed herein is a means for minimizing impurity formation and improving voltage holding characteristics by placing the primary confinement field coil support outboard of the plasma cusp region by extending lobed flanges from the plates of Bitter-type primary electromagnetic field coils into the outboard region and placing the holes for the coil supports through these flanges. This arrangement of coil and flange moves plasma bombardment from the cusp region to the outboard region thus moving impurity generation by coil support bombardment from the cusp region to an outer radius where impurity effects are less detrimental. By extending lobed flanges outboard from the primary Bitter-type electromagnetic field coils, the conductive material of the primary field coil can also be formed into additional secondary Bitter-type electromagnetic field coils that may serve to act as transformers. Termed “Halbach transformers” herein due to their similarity to the way that Halbach arrays of permanent magnets can add or remove magnetic field strength from one side of the array, stacked helical assemblies of lobed flanges formed into Bitter-type electromagnetic transformers provide an option for modulating the primary field inside the reactor at frequencies for heating or driving current. Resonant frequencies of, for example, ion cyclotron resonance, transit-time damping resonance, or at other frequencies, for heating, stirring, or otherwise manipulating the plasma are included herein by reference. By further integrating the modulations of Halbach transformers with the electrodes required for stirring the plasma a plurality of options for controlling plasma motion and behavior are made available including plasmoid formation. Techniques and device configurations for cusped plasma reactors having edge-directed flow and having systems incorporating plasma heating and driving plasma currents are disclosed. In one form, cusped magnetic fields are formed by at least three current-carrying magnetic field coils held in proximity along a shared cylindrical axis, each coil producing a magnetic field B opposite in polarity to its neighboring coils creating a cylindrical column of any number of cusp-shaped magnetic fields. Cusped magnetic fields are known to be a relatively stable means for plasma confinement as compared to closed systems such as the tokamak or field-reversed configuration and are well known to those skilled in the art. In one form, the field coils surround a first vacuum region housing the hot dense plasma. In the cusp region between adjacent field coils the vacuum vessel may be closed axially and azimuthally by a wall, or in another form, at that radius be open axially and azimuthally into a second region of, in one embodiment, electrostatic deceleration electrodes or other means for direct energy conversion [Miley 1976]. Said open cusp configurations would thereby mean that the first primary vacuum vessel is bounded radially by a number of segments of vessel surfaces discontinuous in the axial direction with one another. Said segments house passageways through to the plasma for parts such as electrodes for stirring the plasma with an edge-directed torque, probes for measuring or diagnosing the plasma, antennae for heating or driving current in the plasma, or other parts. Such arrangements of parts are well known to those skilled in the art. The open cusp embodiment is beneficial for, for example, “ash” from nuclear fusion reactions to travel radially through to said second vacuum region outboard of the first region for electrostatic deceleration (direct energy conversion). In the open cusp configuration the whole vacuum region thereby comprises a first region wherein cusped fields bound plasma into a cusped configuration and a second vacuum region radially outboard and continuous with the first region through the cusp region, said second region having, for example, electrostatic deceleration electrodes. Said segments of the first region likewise are parts of closed confinement systems but lack said second vacuum region by virtue of a wall in the cusp region and are thus closed to particle loss out through the cusp as compared to open systems. Examples of closed systems are the Jupiter-2M device built by Lavrent'ev in Russia [Dolan 1994] and the Wisconsin Plasma Astrophysics Laboratory WiPAL in Madison, Wis., USA [Forest 2015].) In one form, electrodes are passed through the primary vacuum vessel wall segments. Typically the electrodes are positioned axially such that they intersect the outboard plasma edge at the low magnetic field regions midway points between cusps [Forest 2015]. Said electrodes polarities are set to potentials that alternate in polarity along the axial length of the device along analogous to the alternating direction of the magnetic field of the cusp configuration such that an azimuthal direction of fluid flow is created consistent in direction along the axial length (relative to the laboratory frame of reference) due to ExB particle drift [Chen 2006]. Electrode current across the magnetic field exerts a JxB torque that spins the plasma at its outer edge. It would be additionally advantageous to eliminate electrode contact with the hot dense plasma in order to minimize impurities. By nature of their operation electrodes must touch the conductive plasma to conduct a current for providing the JxB torque at the plasma edge. Impurities will then sputter into the plasma as the electrode material is ablated. One means for eliminating the electrode may be the use of electrolasers. Said electrolasers can create a plasma channel through the vacuum magnetic field region outboard of the midplane between cusps. In this case said plasma channel can conduct the required current. In the present invention “electrode” may thereby mean also “electrolaser.” In another embodiment of the present invention the plasma is spun by modulations of Halbach transformers. Impurities may also be formed by plasma bombardment onto the supports for the field coils. Plasma impinging onto the supports also provides a surface for voltage breakdown. One means of reducing impurity formation and improving voltage handling is by moving the coil supports radially outward from the cusp. One means may be by housing the reactor in a very large radius vacuum vessel strong enough to support the opposing forces of the stack of opposed magnetic field coils at a radius large enough to also accommodate, for instance, electrostatic deceleration electrodes (typically 300 meters or more, Miley 1976). Another means of removing the field coil supports from contact with hot dense plasma is by forming into the magnetic field coils themselves lobed flanges that provide for axial passageways for the field coil supports. Such lobed flanges have the benefit of additional means for heating, stirring, or otherwise manipulating the plasma when stacks of lobed flanges are formed into helices of the Bitter electromagnet type. Many high-energy plasma physics applications do not require the high cost and complexity associated with present-day superconductors. For example, nuclear fusion may be accomplished with as little as 1T of magnetic field (Chen, 2011, p. 206). With suitable design this magnetic field strength is approachable with conventional resistive electromagnets of the Bitter type. In one form, the reactor field coils may be of the Bitter type, that is, formed of conventional conductor material (for example copper) plates arranged in a helical stack with each layer separated by an insulator as is well known to those skilled in the art. Room-temperature Bitter type electromagnets presently generate the world's strongest continuous magnetic fields at, for example, the National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Fla., USA. In one form, the reactor described herein will have a larger “central bore” than the Bitter-type used at, for example, NHMFL, and may be, for example, a meter or more in radius. Forming the field coils by sheets of conductive material provides a means for placement of the coil supports at a location radially outboard of the high-field cusp region by the use of a plurality of lobed flanges on the outboard radius of the sheet of conductive material. Said outboard lobed flanges may serve a plurality of functions. In one embodiment said lobed flanges may simply house the opening through which the coil supports that support the field coils pass axially. In another embodiment the lobed flanges may be segmented in the way that Bitter electromagnetic field coils are segmented for their helical stacking. In such a case of segmentation and helical stacking of the outboard lobed flanges additional Bitter-type electromagnet assemblies may be formed into, for example, transformers, or in the case of steady-state operation, means for augmenting the primary magnetic field. The transformer operation will be discussed. In one embodiment of the present invention Bitter-type electromagnets outboard and formed into the primary confinement field Bitter-type electromagnetic field coils may comprise transformers. In one embodiment of the present invention these transformers modulate the primary confinement field. In such a case modulation through a duty cycle of the transformer adds and subtracts magnetic field strength from the primary confinement field within the first inner confinement vessel region in a manner analogous to the way that Halbach arrays of permanent magnets add or subtract magnetic field strength from one or the other side of an array of permanent magnets and therefore said transformers are called herein “Halbach transformers.” In one embodiment of the present invention, any number of Halbach transformers are placed radially outboard of any one or a plurality of the primary confinement field coils along the device axis or around its circumference to provide for a plurality of Halbach transformers arranged in an array around the device circumference and along its axis each being individually controllable. Halbach transformer arrays thereby permit a wide variety of multiplexing schemes along both the toroidal and axial directions for purposes of plasma heating, driving currents, plasmoid formation, or for other uses. One simple example of the present invention plasma heating may be accomplished by modulating a circumferential array of Halbach transformers around the device axis in uniform phase at a frequency for ion cyclotron resonance. Plasma ions will thereby by heated preferentially transverse to the magnetic field and the plasma will be heated through collisions and subsequent dispersion as is well known to those skilled in the art. Another example of plasma heating by Halbach transformers may be by transit time damping [Cairns 1991 pg. 24-25]. This heating scheme utilizes periodic modulation of the primary confinement field (in the present invention the cusp field) below the ion cyclotron frequency. The name comes from the fact that, when the collision frequency is small, the optimum power input is obtained when the coil modulation frequency is around the reciprocal of the average ion transit time through the region in which the field is modulated. This method of heating may be of value for cusp reactors, and in particular, cusp reactors with cross-field fluid motion such as Prater, U.S. Pat. No. 9,462,669. In regards to driving currents in the plasma for, for example, plasmoid formation, Halbach transformers may be utilized to drive azimuthal currents by augmenting curved vacuum field and diamagnetic drift currents. By nature of the curvature and gradient of the magnetic field, cusped fields generate plasma drifts leading to currents in an azimuthal direction across the primary cusped field lines. Additionally, the plasma density gradient in the region of the cusp sheath (the outboard-most region of the plasma, a region well known to those skilled in the art) induces an azimuthal current due to plasma diamagnetic drift [Chen 2006]. Augmenting said curved vacuum field and diamagnetic drift currents by pulsed or continuous current drive, using Halbach transformers or radio-frequency antennae mounted on the inner primary vacuum vessel wall said antennae operating either with or without simultaneous Halbach transformer or stirring electrode current modulations, may permit plasmoid formation. Plasmoids may be, for example, toroidal plasma structures with dynamo properties, that is, self-sustaining currents and magnetic fields. Such dynamo plasmoid structures may be useful for further utility of said invention. In the present invention the electrode potentials and magnetic fields are modulated or multiplexed in concert, for example through combined action of Halbach transformer modulations alongside electrode current modulations, for additional means of heating, stirring, driving current, or otherwise manipulating the plasma. Having spatial and temporal control of both current and magnetic field strength, for example through the control of multiple Halbach transformers and electrodes, thereby provides numerous possibilities for controlling plasma motion and behavior. In another embodiment it may be found advantageous to decrease the Halbach transformer inductance by decreasing its total number of turns. One means of decreasing the number of turns is by not having a lobed flange segments extending from every layer of the primary field coil helical stack, for example, by utilizing lobed flanges on every other field coil layer, thereby having a Halbach transformer with fewer turns. Further means of increasing the frequency of electromagnetic resonance are well known to those skilled in the art. Higher-frequency electromagnetic modulations than are capable by Halbach transformers may be desirable for heating or driving plasma current or other means. Examples of these frequencies are those in the range of, for example, ion cyclotron resonance, hybrid resonance, minority species resonance, or electron cyclotron resonance and require special antennae or coil structures in the primary vacuum vessel inner wall as is well known to those skilled in the art [Cairns 1991]. Other means of current drive may include, but are not limited to, neutral beam injection in a similar fashion as tokamak reactor current drive (but in cusp reactors toroidal current will be perpendicular to field lines rather than parallel to field lines as in the tokamak reactors), or electrolaser ionization of vacuum-region plasma for the creation of a plasma channel such that current may be conducted along said channel. In accordance with this embodiment said electrodes or electrolasers may combine current driving with stirring of the plasma fluid. Heating, stirring, driving currents, or other plasma manipulations, may use parts that require passageways to the reactor primary inner vacuum region. Such passageways may be accessible by the use of advanced Bitter-type constructions such as the Split Florida-Helix Bitter-type electromagnet construction means (U.S. Pat. No. 7,609,139 B2 to Bird et al. which is specifically incorporated herein by reference) for the Halbach transformers or primary field coils. Additionally, the use of advanced Bitter-type electromagnet constructions provide for means of passing coolant through the Halbach transformers and primary field coils as well as provide means for radial passageways to the reactor interior from, for example, the inner part of the field coil support. In one embodiment the cooling channels may be designed for the extraction of additional heat generated by, for example, nuclear fusion reactions. In a related embodiment, channels may be formed across the coil radius, for passing electrodes, diagnostic probes, or other parts to the reactor interior. Such cooling channels and radial passageways are features of advanced Bitter-type electromagnet construction means. It is an object of the present invention to provide for increased plasma confinement by cusp reactors. Preferential transverse heating by, for instance ion cyclotron resonance or transit time damping heating by Halbach transformers, should decrease plasma losses out through the cusp. Cross-field fluid flow decreases cross-field ambipolar diffusion [Maggs 2007]. By itself this should decrease cusp losses [Cooper 2016], but also cross-field flow increases the pressure gradient at the sheath, and this should increase diamagnetic drift currents. These currents are in the same direction as curved vacuum field currents and oppose in adjacent cusp-field sheaths [Chen 2006). Additionally high-beta (high plasma pressure relative to magnetic field pressure) confinement improves cusp losses [Park 2015]. Further the cusp sheath comprises a population of mirror-confined particles [Spalding 1971 and Kaye 1974]. Heating across field lines, for example at ion cyclotron resonance frequency, increases the radial-axial breadth of mirror-confined particle populations. The combined expansion of mirror-confined plasma species in the cusp sheath, coupled with a decrease in cross-field ambipolar diffusion to increase opposed sheath currents, and improved confinement at high beta, leads adjacent sheath currents to “choke” the cusp loss region to bulk plasma losses. Additional azimuthal current driven in the plasma may increase this effect. A current pulse driven azimuthally across field lines may generate plasmoids with dynamo action. It should be well appreciated that various details of the present invention may be changed without departing from the spirit and scope of the invention. Furthermore, the foregoing description is for illustration only, and not for the purpose of limitation. Dolan, T. J. 1994 Magnetic Electrostatic Plasma Confinement Plasma Physics and Controlled Fusion 36, pp. 1539-1593, doi:10.1088/0741 3335/36/10/001. Abdrashitov, G. F. et al 1991 Hot Rotating Plasma in the PSP-2 Experiment Nuclear Fusion 31, 7. Miley, G. F. 1976 Fusion Energy Conversion, American Nuclear Society. Prater, D. N. 2016 Plasma Confinement Device, U.S. Pat. No. 9,462,669. Forest, C. B. et al 2015 The Wisconsin Plasma Astrophysics Laboratory Journal of Plasma Physics 81, 5. Chen, F. F. 2011 An Indispensable Truth: How Fusion Power Can Save the Planet, Springer. Cairns, R. A. 1991 Radiofrequency Heating of Plasmas, IOP Publishing Ltd. Bird, M. D. et al 2009 Split Florida-Helix Magnet, U.S. Pat. No. 7,609,139 B2. Chen, F. F. 2006 Introduction to Plasma Physics and Controlled Fusion, Volume 1, Plasma Physics, Sprinter 2nd edition. Maggs, J. E., Carter, T. A., Taylor, R. J. 2007 Transition from Bohm to classical diffusion due to edge rotation of a cylindrical plasma Physics of Plasmas 14, 052507. Cooper, C. M., et al 2016 Direct measurement of the plasma loss width in an optimized, high ionization fraction, magnetic multi-dipole ring cusp Physics of Plasmas 23, 10, 102505. Park, J., et al 2015 High-energy electron confinement in a magnetic cusp configuration Physical Review X5, 021024. Spalding, I., 1971 Cusp Containment Advances in Plasma Physics 4, 79-123. Kaye, A. S. 1974 Plasma losses through an adiabatic cusp Journal of Plasma Physics 11, 1, 77-91.
062352237	summary	BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The invention relates to a sintered nuclear fuel body or compact that contains (U, Pu)O.sub.2 mixed crystals. The invention also relates to a method for producing a sintered nuclear fuel body that contains (U, Pu)O.sub.2 mixed crystals from powdered starting materials of uranium dioxide UO.sub.2+X and plutonium dioxide PuO.sub.2, which are ground, compressed into bodies, and sintered as bodies in a hydrogen-containing sintering atmosphere. The variable X is in a range from 0 to 0.3. One such sintered nuclear fuel body and one such method are known from German Published, Non-Prosecuted Patent Application DE 38 02 048 A1. In that known method, the powdered starting materials of uranium dioxide and plutonium dioxide are ground together with an additive, which is at least one powdered substance selected from the group consisting of ammonium uranyl carbonate, ammonium diuranate, ammonium bicarbonate, zinc stearate, zinc behenate, starch, cellulose, oxalic acid diamide and stearic acid diamide. The powder mixture can be ground and then compressed into tablet-like bodies, which are sintered in a sintering atmosphere of hydrogen. The sintered nuclear fuel bodies that are obtained are dimensionally stable and also only have slight open porosity, so that gaseous nuclear fission products in a nuclear reactor can be trapped in the sintered nuclear fuel bodies SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide a sintered nuclear fuel body and a method for producing a sintered nuclear fuel body, which overcome the hereinafore-mentioned disadvantages of the heretofore-known products and methods of this general type, which further improve retention of gaseous nuclear fission products and in particular assure the same even if the sintered nuclear fuel bodies are located in a nuclear reactor for long periods of time and output high power. With the foregoing and other objects in view there is provided, in accordance with the invention, a sintered nuclear fuel body, comprising (U, Pu)O.sub.2 mixed crystals having a mean particle size in a range from 7.5 .mu.m to 50 .mu.m. In accordance with another feature of the invention, the (U, Pu)O.sub.2 mixed crystals have a mean particle size in a range from 8 .mu.m to 25 .mu.m. This relatively large mean particle size changes only insignificantly during the power output of the sintered nuclear fuel body in a nuclear reactor, so that the gaseous fission products that are produced remain at the site where they were created in the sintered nuclear fuel body and are not released. The determination of the mean particle size is carried out in accordance with a book by H. Schumann entitled "Metallographie" [Metallography], 10th Edition, VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig, Germany, pp. 51-57. With the objects of the invention in view, there is also provided a method for producing a sintered nuclear fuel body containing (U, Pu)O.sub.2 mixed crystals, which comprises adding at least one powdered substance selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, chromium oxide, vanadium oxide, aluminum hydroxide, chromium hydroxide, aluminum monostearate, aluminum distearate and aluminum tristearate as an additive to powdered starting materials of uranium dioxide UO.sub.2+X and plutonium dioxide PuO.sub.2 at least one of before, during and after grinding the starting materials, compressing the ground starting materials into a body, and/or sintering the body during a holding time of 10 minutes to 8 hours at a sintering temperature in a range from 1400.degree. C. to 1800.degree. C. in a hydrogen-containing sintering atmosphere having an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar during a first portion of the holding time and having an oxygen partial pressure of 10.sup.-8 to 10.sup.-10 bar during an ensuing second portion of the holding time, and then cooling down the body in a hydrogen-containing atmosphere with an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar. Both the additive and the oxygen partial pressure, especially during the second portion of the holding time, bring about high mobility on the part of uranium, plutonium and oxygen during sintering in the body, thus promoting a uniform, increased particle growth during the sintering of the body. In accordance with another mode of the invention, there is provided a method which comprises maintaining the sintering temperature at an at least approximately constant value in a range from 1400.degree. C. to 1800.degree. C. This further increases the mobility of uranium, plutonium and oxygen atoms. In accordance with a further mode of the invention, there is provided a method which comprises heating the body to the sintering temperature in the hydrogen-containing atmosphere having an oxygen partial pressure of 10.sup.-10 to 10.sup.-20 bar. This effects calcination of hydroxides of the additives into oxides, having a crystal lattice structure which is quite similar to the lattice structure of uranium oxide and plutonium oxide, that promotes the formation of (U, Pu)O.sub.2 mixed crystals. In accordance with an added mode of the invention, there is provided a method which comprises maintaining the sintering temperature in a range from 1600.degree. C. to 1800.degree. C. and preferably from 1650.degree. C. to 1750.degree. C. In accordance with an additional mode of the invention, there is provided a method which comprises heating the body to the sintering temperature in temperature stages. In accordance with yet another mode of the invention, there is provided a method which comprises providing the hydrogen-containing sintering atmosphere with from 2 to 10 volume % hydrogen and at least one gas selected from the group consisting of noble gas, nitrogen, CO.sub.2, CO, O.sub.2 and water vapor. This brings about an especially high oxygen partial pressure during sintering. In accordance with yet a further mode of the invention, there is provided a method which comprises selecting the first portion of the holding time to be in a range from 10 minutes to 4 hours. In accordance with a concomitant mode of the invention, there is provided a method which comprises selecting the second portion of the holding time to be in a range from 10 minutes to 4 hours and preferably from 2 to 3 hours. These modes bring about a large proportion of the (U, Pu)O.sub.2 mixed crystal in the sintered nuclear fuel body. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a sintered nuclear fuel body and a method for producing a sintered nuclear fuel body, it is nevertheless not intended to be limited to the details given, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific examples.
	abstract	In various embodiments, a method of processing one or more semiconductor wafers is provided. The method includes positioning the one or more semiconductor wafers in an irradiation chamber, generating a neutron flux in a spallation chamber coupled to the irradiation chamber, moderating the neutron flux to produce a thermal neutron flux, and exposing the one or more semiconductor wafers to the thermal neutron flux to thereby induce the creation of dopant atoms in the one or more semiconductor wafers.
052356272	claims	1. An X-ray diagnostic system comprising: an X-ray source including a movable X-ray diaphragm unit; an X-ray camera unit for radiographing a patient as an object; a holding means for holding the X-ray source and the X-ray camera unit in opposition and maintaining sufficient operating space between them; a first seeking means for seeking an offset in an X-ray irradiated field said first seeking means comprising a first measuring device for measuring an angle of rotation of the arm around an axis of the patient to be X-rayed, a second measuring device for measuring an angle of rotation of the arm in a plane including the axis, and a third measuring device for measuring a distance SID; and a control means for controlling the X-ray diaphragm unit according to an output of said seeking means. the movable X-ray diaphragm unit includes a plurality of movable wings for limiting an X-ray irradiated field. the controlling means is provided with a compensating table for calculating compensating amounts according to data from the seeking means. the control means is further provided with a second seeking means for seeking compensating amounts experimentally according to data from the first seeking means and the offsets of the X-ray irradiated field. the X-ray diaphragm apparatus includes four movable wings which form a rectangular aperture and can be moved to eliminate the offsets. the X-ray diaphragm apparatus includes four movable wings which form a substantially circular aperture and can be moved to eliminate the offsets. the X-ray diaphragm apparatus includes four movable wings which form a rectangular aperture and four movable wings which form a substantially circular aperture. 2. An X-ray diagnostic system as claimed in claim 1, wherein: 3. An X-ray diagnostic system as claimed in claim 2, wherein: 4. An X-ray diagnostic system as claimed in claim 3, wherein: 5. An X-ray diagnostic system as claimed in claim 1, wherein: 6. An X-ray diagnostic system as claimed in claim 1, wherein: 7. An X-ray diagnostic system as claimed in claim 1, wherein:
	description	The present invention relates to radiation sources that may be used, for example, in the calibration of nuclear imaging equipment, such as gamma or other nuclear measuring systems such as SPECT or PET cameras. The present invention is also directed to methods of making and using such radiation sources. Embodiments of the present invention are directed to a radiation source that contains a substrate upon which a radioactive deposit has been deposited. The radioactive deposit may be deposited as a solution and affixed to the surface of the substrate to prevent movement of the radioactive deposit during use of the radiation source. In embodiments of the invention, the substrate may be flexible, so that the form factor of the substrate may be reduced (e.g., by manipulating the shape of the substrate, such as by folding or rolling) for shipment in a smaller shielded container. In embodiments of the source of the present invention, the outer housing containing the substrate may be opened so that a depleted substrate may be replenished or an additional compensatory substrate may be inserted. Embodiments of the method of making sources according to the present invention may involve forming a radioisotope-containing solution that can be deposited on the surface of the substrate in a selected radioactive deposit. The radioisotope-containing solution may include a radioisotope (or some form thereof) and a solvent. In embodiments of the invention, the solution may also contain a binding agent to affix the radioisotope to the surface of the substrate. In embodiment of the invention, the solution may be deposited on the surface of the substrate using a inkjet-type printhead. FIG. 1 illustrates a circular flood source according to an embodiment of the present invention. The source is enclosed in an outer housing 1, a portion of which is shown as removed to reveal the inner substrate 2 and radioactive deposit 3 contained therein. The outer housing 1 may be relatively thin and made of a radiotranslucent material, such as aluminum or plastic. This allows radiation emitted from the substrate 2 to pass through the outer housing 1 for imaging by an imaging device. In embodiments of the invention, the outer housing 1 may be sufficiently rigid to allow fixed mounting of the source during calibration procedures. The outer housing 1 may contain a substrate 2 having a xe2x80x9cfrontxe2x80x9d surface upon which the radioactive deposit 3 may be deposited to achieve a desired activity pattern. In embodiments of the invention, the substrate 2 may be fixed in place in the outer housing 1 by an adhesive, pins, clips, or some other attachment feature, while in other embodiments, the substrate 2 may be fixed in place within the outer housing 1 by the size and/or shape of the outer housing 1 relative to the substrate 2. In some flood source embodiments, the activity pattern may be uniform across the entire surface of the substrate. In other embodiments, the radioactive deposit 3 may be drawn to mimic an implanted radiation emitter (e.g., a brachytherapy seed) or may be drawn to match a specified pattern of spatial distribution and/or activity level (intensity). In particular embodiments of the invention, the substrate 2 may be a flexible sheet of paper, plastic or some other material. The substrate 2 material may be selected based upon its ability to retain the radioactive deposit 3 in a fixed form. The substrate 2 may be radiopaque, such that radiation is emitted from only the surface of the substrate 2 upon which the radioactive deposit 3 is deposited. The radioactive deposit 3 imprinted on the substrate 2 may include a radioisotope with a relatively long half-life, such as Cobalt-57 or Gold-153. Although the radioactive deposit 3 is described as being deposited on a xe2x80x9csurfacexe2x80x9d of the substrate 2, it should be noted that this surface need not be exposed. For example, the surface of the substrate 2 upon which the radioactive deposit 3 is deposited may be covered with a sealing layer, such as a layer of plastic or polymer. The sealing layer may be radiotranslucent and may be applied by heating (e.g., lamination), immersion (e.g., in a bath), painting, spraying or a similar suitable process. A sealing layer may be deposited to affix the radioactive deposit to the surface of the substrate 2 and/or to prevent damage to, or removal of, the radioactive deposit 3 or substrate 2. In an embodiment of the invention, the radioactive deposit 3 may be deposited on the surface of the substrate 2 in the form of a solution (the xe2x80x9cdeposited solutionxe2x80x9d). The deposited solution may contain dissolved radioisotope, a solvent and a binding agent. The solvent may be an inorganic solvent (e.g., water) or an organic solvent, (e.g., isopropyl or other alcohols, oils, ketones, esters, or glycols), and the solution may created by dissolving a salt or other compound formed from the radioisotope in the solvent. In an alternative embodiment, the radioisotope may be adsorbed or chemisorbed to a particulate carrier that is evenly dispersed throughout the solution. In alternative embodiments of the invention, the deposited solution may contain a radioisotope precursor that is rendered a radioisotope by neutron bombardment after deposition on the substrate 2. The solvent may evaporate after the deposited solution has been deposited on the surface of the substrate 2, leaving the radioisotope and the remaining ingredients in the deposited solution to form the radioactive deposit 3. In embodiments of the invention, the deposited solution may also contain a binding agent, such as an organic resin (e.g., acrylics, styrenes, polyesters, polyamides, polyvinyl acetate copolymers, polyketones, phenolics, polyvinylbutyrals, polyvinylpyrrolidones, and maleic anhydride copolymers) or an inorganic binding agent (e.g., sodium silicate). Such binding agents may be used to affix the radioactive deposit 3 to the surface of the substrate 2 and may be chosen based on the characteristics of the substrate 2 and the characteristics of other elements in the deposited solution. For example, the binding agent may be chosen based upon the effects of a radioisotope""s activity on its ability to bind to the surface of the substrate 2 or its viscosity during the deposition process. In further embodiments of the invention, the deposited solution may include a colorant, such as, a dye or pigment. The color of the colorant may correspond to the radioisotope or radioisotope precursor in the deposited solution. Moreover, as described in greater detail with respect to FIG. 2, in the radioactive deposit 3 as deposited, the colorant may serve as a visual indicator of the activity level of various portions of the radioactive deposit 3 or of the radioactive deposit 3 as a whole. In such embodiments, the accuracy of the deposition process in creating a uniform or specified radioactive deposit 3 may be visually verified during the manufacturing process by inspecting the color pattern created by the colorant. The outer housing 1 may include a border 4. The border 4 may be radiopaque so as to minimize radiation emitted into the hands of personnel maneuvering the source during calibration procedures without substantially changing the radioactive deposit of the source as seen by the imaging device. Although not shown in the pictured embodiment, the border may include handles or other features that make handling of the source by personnel more convenient. Furthermore, the back surface of the outer housing 1 or the substrate 2 may be radiopaque to further minimize radiation exposure to handling personnel. FIG. 2 illustrates a system that may be used to deposit the radioactive deposit 3 on the surface of the substrate 2 according to an embodiment of the present invention. The blank substrate 2 may be passed in front of a liquid deposition head 101. In embodiments of the invention, the liquid deposition head 101 may be an inkjet-type printhead as can commonly be found in the InkJet or DesignJet lines of inkjet printers available from Hewlett-Packard Company of Palo Alto, Calif. or the Stylus line of inkjet printers available from Seiko Epson Corporation of Japan. In particular embodiments, a large-format inkjet-type printer may be used to accommodate a large substrate 2. The blank substrate 2 may be positioned relative to the liquid deposition head so that the deposited solution may be placed on different portions of the front surface of the substrate 2. In the embodiment shown in FIG. 2, this may be achieved by rotating rollers 102a and 102b and 103a and 103b so as to move the substrate 2 while the position of the liquid deposition head 101 remains fixed. One or more of the rollers 102a and 102b and 103a and 103b may be driven by a motor. In the embodiment shown in FIG. 2, the rollers 102a and 102b and 103a and 103b are paired as pinch rollers. Such an embodiment may be particularly suitable where the substrate 2 is in the form of a cut sheet. In alternative embodiments, different roller configurations may be used to move the substrate 2. For example, in embodiments of the invention in which the substrate 2 is a continuous web, unpaired rollers may be used and one surface of the substrate 2 (e.g., the back surface) may be held in tension against the surface of the rollers. The continuous web of substrate 2 may be cut into individual sheets of substrate 2 after the radioactive deposit 3 has been deposited on the front surface. In other embodiments of the invention, the substrate 2 may be moved using different feeding mechanisms, such as a vacuum belt, air bearing or the like. These feeding mechanisms may be chosen to minimize contact with the front surface of the substrate before the radioactive deposit 3 has been affixed thereon. Alternatively, the liquid deposition head 101 may be moved relative to a fixed-position substrate. In such an embodiment, the liquid deposition head 101 may be mounted on a carriage and the carriage may be moved in the x-, y- and/or z-axes using drive screws. As generally described above, the radioactive deposit 3 may be created by placing the deposited solution 104 on the front surface of the substrate 2. A controller 106 may communicate with the liquid deposition head 101 to control the placement of the deposited solution 104 on the front surface of the substrate 2. Control signals from the controller 106 to the liquid deposition head 101 may control the rate at which the deposited solution 104 is released from the liquid deposition head 101. Moreover, in embodiments in which the liquid deposition head 101 includes multiple openings, nozzles or jets (hereinafter commonly referred to as xe2x80x9copeningsxe2x80x9d) through which the deposited solution 104 may be released, the control signals from the controller 106 may be used to selectively open and close or activate and deactivate these openings. The deposited solution 104 may be stored in a container 105 and fed to the liquid deposition head 101 through a feed source 108 and a feed line 107 (or multiple feed lines in embodiments in which the liquid deposition head 101 has multiple openings). In embodiments of the invention, the feed source 108 may be a pump or other device suitable for causing forced flow of the deposited liquid 104. The characteristics of the feed source may be selected based on the viscosity of the deposited liquid, the size of the feed line 108 and other factors. The feed source 108 may receive signals from the controller 106 so as to control the flow of deposited solution 104 to the liquid deposition head 101. The received control signals may regulate the differential pressure applied by the feed source 108 to generate forced flow or may direct flow to specified feed lines in embodiments in which multiple feed lines are used. In other embodiments, the feed source 108 may be a valve and differential pressure to force flow of the deposited solution to the feed line 107 may be created by a sufficient gravity head. In alternative embodiments, the dissolved radioisotope (i.e., radioisotope and solvent solution) may be stored in the container 105 and mix in additional ingredients of the deposited solution 104 shortly before deposition of the radioactive deposit 3. This may be desirable in embodiments in which the fluid properties of other ingredients of the deposited solution 104 (e.g., binding agent, colorant) are adversely affected by the activity of the radioisotope. In such embodiments, mixing may be done within the liquid deposition head 101 or in a separate mixing tank positioned between the feed source 108 and the liquid deposition head 101. In embodiments of the invention in which the liquid deposition head 101 is moved, the feed line 107 may be flexible and/or extendible so as to permit a suitable range of motion for the liquid deposition head 101. The size of the feed line may be selected based upon the viscosity of the deposited solution 104 so as to ensure free flow of the deposited solution 104 to the liquid deposition head 101. The connections between the feed line 107 and the feed source 108 and between the feed line 107 and the liquid deposition head may be made liquid-tight. Particularly in embodiments in which the deposited solution contains active radioisotope, liquid-tight connections may minimize the amount of active deposited solution leaking during the deposition process so as to lessen radiation exposure to manufacturing personnel and minimize radioactive waste produced during the manufacturing process. In embodiments in which the deposited solution 104 contains active radioisotope, the container 105 may be shielded so as to minimize the radiation exposure of other components in the system. Where the deposited solution 104 contains a solvent or other ingredient that is susceptible to evaporation, the container 105 may be sealed to prevent such evaporation. In particular embodiments of the invention, the container may be similar to a standard inkjet-type ink cartridge. In embodiments of the invention, the deposition process may be done in layers, with each layer being associated with a uniform activity density and additional layers being deposited on portions of the radioactive deposit 3 corresponding to higher levels of activity. This process may resemble the hue-saturation-value process for inkjet-type printing. In fact, in embodiments in which the deposited solution 104 includes a colorant, the resulting radioactive deposit 3 may resemble grayscale or color printing carried out using a hue-saturation-value process. Alternatively, the radioactive deposit 3 may be broken down into a number of areas (xe2x80x9cpixelsxe2x80x9d) and the number of drops of deposited solution 104 placed within a pixel of the radioactive deposit 3 may determine the activity level of the pixel. In embodiments of the invention in which each pixel is relatively small, the resulting radioactive deposit may appear consistent as a result. In embodiments of the invention involving thermal xe2x80x9cprinting,xe2x80x9d the deposited solution 104 may be propelled out of the liquid deposition head 101 by heating a resistive element within the liquid deposition head 101 to create a bubble in the chamber filled with the deposited solution 104. As the resistive element is heated, the bubble expands, pushing the deposited solution out of the liquid deposition head 101 toward the surface of the substrate 2. In alternative embodiments involving vibrational xe2x80x9cprinting,xe2x80x9d deposited solution 104 may be expelled from the liquid deposition head 101 by the vibration of a transducer. The transducer may have piezo-electric properties (i.e., may expand or contract when electrical current is passed through it), and vibration may be induced by charging or removing charge from the transducer. While the description above focuses on the use of an inkjet-type printing mechanism, a person of ordinary skill in the art will recognize that other types of printing devices may be used to place the radioactive deposit 3 on the surface of the substrate 2. For example, a variety of impact or non-impact printers (e.g., solid ink printers, dot matrix printers, character printers, thermal wax printers), plotters, airbrushes or the like may be used. Returning to FIG. 1, in embodiments of the invention, the outer housing 1 may be opened so that the substrate 2 with the deposited radioisotope 3 may be removed. In such embodiments, the outer housing 1 may include a fastener. Furthermore, in such embodiments, the outer housing 1 may be hinged or otherwise constructed so that the parts of the outer housing 1 remain in contact at a point(s) when the outer housing 1 is opened. This may prevent misalignment of the parts of the outer housing 1 when the outer housing 1 is closed. The fastener may be a lock, a snap or a similar latching mechanism that may be selectively unfastened and may require a key, dial combination or other access device for opening. Alternatively, the fastener may be a screw, pin or other mechanism that must be removed for the outer housing to be opened. In some embodiments, the outer housing may be opened by personnel using the source or other personnel at the customer""s site, so that depleted substrates can be shipped back to the manufacturer for replenishment. Where the substrate 2 is flexible, the using personnel may change the shape of the substrate 2 to reduce its form factor (e.g., by manipulating the substrate by rolling it into a cylindrical shape or folding it) and the protective shipping container may be smaller in size than the expanded substrate 2. Because the shipping container must be fully-shielded and because shielding materials are generally heavy, shipping the depleted substrates 2 back to the manufacturer (and shipping replenished substrates to the customer) without the outer housing 1 and with smaller shipping containers may significantly reduce shipping expenses. In embodiments with a outer housing 1 that may be opened, the entire source, when depleted, may be returned to the manufacturer. The manufacturer may open the outer housing 1, measure the remaining activity level of the depleted substrate 2 (xe2x80x9cthe pattern of depleted activityxe2x80x9d) and create a second substrate with an activity level matching the difference between that of a fresh substrate and the depleted substrate 2. The manufacturer may then place the second substrate in the outer housing 1 and close the outer housing 1 before sending it back to the customer as a fresh source. In such a system, the manufacturer may note that the depleted substrate 2 exhibits a pattern of depleted activity and may cause the second substrate to be imprinted with a compensatory pattern of deposited radioisotope so that the combined activity pattern of the depleted substrate 2 and the second substrate substantially matches the activity pattern of a fresh substrate. Alternatively, the compensatory pattern of deposited radioisotope may be deposited over the depleted radioactive deposit 3 on the first (depleted) substrate 1. The pattern of depleted activity may be even or uneven depending, in part, upon whether the radioactive deposit 3 initially deposited on the substrate was uniform or not, whether one or more types of radioisotopes were combined to form the radioactive deposit 3, etc. While the description above refers to particular embodiments of the present invention, it should be readily apparent to people of ordinary skill in the art that a number of modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true spirit and scope of the invention. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning of and range of equivalency of the claims are intended to be embraced therein.
061372463	abstract	A charge-exchange device is disclosed which is able to considerably reduce, without the use of foils, radio activation caused by a beam deflection angle and, which also implements a further efficiency and reduction of a laser output. The charge-exchange device is provided with an undulator and an optical resonator. The undulator magnetic field which has been generated by the undulator generates the Lorentz electric field by interaction with the relativistic velocity of H.sup.0 neutral beam being injected. The optical resonator amplifies the photon density of the laser beam and causes it to collide against the injected H.sup.0 neutral beam, thereby resonantly exciting the H.sup.0 beam to the principal quantum number of 4. The H.sup.0 beam which has been resonantly excited or excited by the relativistic Doppler effect in the undulator magnetic field is ionized to H.sup.+ ion by the Lorentz electric field.
	description	This invention was made with Government support under Agreement No. HR0011-07-9-0007 awarded by DARPA. The Government has certain rights in the invention. 1. Technical Field The present invention relates generally to semiconductor manufacturing and related technologies. More particularly, the present invention relates to electron beam lithography. 2. Description of the Background Art As is well-understood in the art, a lithographic process includes the patterned exposure of a resist so that portions of the resist can be selectively removed to expose underlying areas for selective processing such as by etching, material deposition, implantation and the like. Traditional lithographic processes utilize electromagnetic energy in the form of ultraviolet light for selective exposure of the resist. As an alternative to electromagnetic energy (including x-rays), charged particle beams have been used for high resolution lithographic resist exposure. In particular, electron beams have been used since the low mass of electrons allows relatively accurate control of an electron beam at relatively low power and relatively high speed. Electron beam lithographic systems may be categorized as electron-beam direct write (EBDW) lithography systems and electron beam projection lithography systems. In EBDW lithography, the substrate is sequentially exposed by means of a focused electron beam, wherein the beam either scans in the form of lines over the whole specimen and the desired structure is written on the object by corresponding blanking of the beam, or, as in a vector scan method, the focused electron beam is guided over the regions to be exposed. The beam spot may be shaped by a diaphragm. EBDW is distinguished by high flexibility, since the circuit geometries are stored in the computer and can be optionally varied. Furthermore, very high resolutions can be attained by electron beam writing, since electron foci with small diameters may be attained with electron-optical imaging systems. However, it is disadvantageous that the process is very time-consuming, due to the sequential, point-wise writing. EBDW is therefore at present mainly used for the production of the masks required in projection lithography. In electron beam projection lithography, analogously to optical lithography, a larger portion of a mask is illuminated simultaneously and is imaged on a reduced scale on a wafer by means of projection optics. Since a whole field is imaged simultaneously in electron beam projection lithography, the attainable throughputs can be markedly higher in comparison with electron beam writers. Disadvantages of conventional electron beam projection lithography systems includes that a corresponding mask is necessary for each structure to be exposed. The preparation of customer-specific circuits in small numbers is not economic, because of the high costs associated with mask production. One embodiment relates to a method of controllably reflecting electrons from an array of electron reflectors. An incident electron beam is formed from an electron source, and the incident beam is directed to the array of electron reflectors. A first plurality of the reflectors is configured to reflect electrons in a first reflective mode such that the reflected electrons exiting the reflector form a focused beam. A second plurality of the reflectors is configured to reflect electrons in a second reflective mode such that the reflected electrons exiting the reflector are defocused. Another embodiment relates to an apparatus of a dynamic pattern generator for reflection electron beam lithography. The apparatus includes a plurality of electron reflectors in an array. Control circuitry is provided for configuring a first plurality of the reflectors to reflect electrons in a first reflective mode such that the reflected electrons exiting the reflector form a focused beam and for configuring a second plurality of the reflectors to reflect electrons in a second reflective mode such that the reflected electrons exiting the reflector are defocused. Other embodiments, aspects and features are also disclosed. FIGS. 1A and 1B are diagrams illustrating the basic operation of a conventional dynamic pattern generator. FIG. 1A shows a cross-section of a DPG substrate 102 showing a column (or row) of pixels. Each pixel includes a conductive area 104. A controlled voltage level is applied to each pixel. In the example illustrated in FIG. 1A, four of the pixels 104 are “on” (reflective mode) and are grounded (have 0 volts applied thereto), while one pixel (with conductive area labeled 104x) is “off” (absorptive mode) and has a positive voltage (1 volt) applied thereto. The specific voltages will vary depending on the parameters of the system. The resultant local electrostatic equipotential lines 106 are shown, with distortions 106x relating to “off” pixel shown. In this example, the incident electrons 108 approaching the DPG 112 come to a halt in front of and are reflected by each of the “on” pixels, but the incident electrons 108x are drawn into and absorbed by the “off” pixel. The resultant reflected current (in arbitrary units) is shown in FIG. 1B. As seen from FIG. 1B, the reflected current is “0” for the “off” pixel and “1” for the “on” pixels. FIG. 2 is diagram illustrating a substantial operational distinction between a pixel of a conventional dynamic pattern generator and a pixel of an innovative dynamic pattern generator in accordance with an embodiment of the invention. As seen, there are two states, an ON state and an OFF state, for each pixel. As shown in FIG. 1, for a conventional DPG, the pixel reflects electrons in the ON state and absorbs electrons in the OFF state (or vice versa). In contrast, for an innovative DPG in accordance with an embodiment of the present invention, the pixel reflects electrons in both the ON and OFF states. While the incident electrons are reflected in both ON and OFF states, the mode of reflection differs between the ON and OFF states. As shown, the pixel may reflect electrons in “Mode A” in an ON state and in “Mode B” in an OFF state (or vice versa). As described further below, for example, the electrons may be reflected in a focused or parallel manner in Mode A and may be reflected in a de-focused or divergent manner in Mode B. FIG. 3A is a cross-sectional diagram of a switchable multiple-electrode electron reflector for a pixel of a dynamic pattern generator in accordance with an embodiment of the invention. The electron reflector structure shown in FIG. 3A includes multiple stacked electrodes configured to collect, focus (or de-focus), and extract electrons in accordance with an embodiment of the invention. As shown, the sidewalls surrounding each well (cup) opening 302 comprises a stack with multiple conductive layers or electrodes (for example, 311, 312, 313, and 314) separated by insulating layers 310. In addition, each well includes a base electrode 320 at the bottom of each well. The stacked electrode well structure may be fabricated on a silicon substrate (with an oxide layer on the substrate). As shown in FIG. 3A, a preferred embodiment may include the base electrode and four stacked electrodes (five electrodes total) in the well structure. Other embodiments may include a total number of electrodes in a range from three to ten electrodes in the well structure (i.e. a base electrode and from two to nine stacked electrodes). Each stacked electrode layer is, in effect, a microlens array fabricated on a silicon substrate. The particular implementation shown in FIG. 3A is further described as follows. Other specific dimensions and voltages may be utilized in other implementations, depending on the particular system being implemented. As shown in FIG. 3A, each well may be about 1.4 microns across. In one example implementation, the voltages applied to the electrodes may be as follows. The “top” conductive layer (Electrode 1) 311 may have an applied voltage of, for example, positive 3 volts. This relatively weak positive voltage applied to the uppermost conductive electrode to both screen the insulator from the incoming electron current and to deflect the incoming electrons with lower energy towards the inside of a nearest well. The “upper” conductive stack layer (Electrode 2) 312 (about 1 micron below the “top” conductive stack layer) may have an applied voltage of, for example, positive 8.1 volts. This relatively strong positive voltage is applied to this electrode (which is just beneath the uppermost electrode) so as to both focus the incoming electrons by drawing them into the well and extracting the reflected electrons by drawing them out of the well. The “middle” conductive stack layer (Electrode 3) 313 (about 1 micron below the “upper” conductive stack layer), and the “lower” conductive stack layer (Electrode 4) 314 (about 1 micron below the “middle” conductive stack layer) and may have applied voltages of +6.9 volts and +2.2 volts, respectively. The voltages applied to these two electrodes in the stack may be used to focus the electrons. Finally, the base electrode 320 may have an applied voltage that is switched between two voltage levels in order to achieve the two different reflective modes (Mode A and Mode B). For example, a voltage of negative 1.3 volts (−1.3 V) may be applied to the base electrode to achieve Mode A (the reflective mode for the ON state), while a voltage of positive 0.2 volts (+0.2 V) may be applied to the base electrode to achieve Mode B (the reflective mode for the OFF state). In Mode A, the focal length of the reflecting electron-optics is at or near infinity. This results in a reflected beam which is focused so that a substantial portion of the beam passes through the pupil aperture of the projection electron-optics. In contrast, in Mode B, the focal length of the reflecting electron-optics is such that the focal point lies within the well structure. This creates a divergence or de-focusing of the reflected electron beam which allows only a very small portion of the beam through the pupil aperture of the projection electron-optics. Note that the above example voltages applied to the electrodes are provided for illustrative purposes. The voltages applied in an actual system will vary depending on the implementation. For instance, while the voltage on the base electrode is increased by 1.5 volts to go from Mode A to Mode B in the above-described implementation, decreasing the voltage on the base electrode by 1.5 volts may also work to go from Mode A to Mode B in another implementation. FIG. 3B is a diagram showing a top down view of a portion of a dynamic pattern generator in accordance with an embodiment of the invention. As seen, this embodiment comprises well openings or cavities 302 that are round-shaped in a square grid. For example, the well openings may be 1.4 microns in diameter, and the pitch of the square grid may be 1.5 microns in diameter. As discussed above in relation to FIG. 3A, the interstitial regions 350 comprise the sidewalls of the wells and may be formed with a metal-insulator-metal-insulator-metal-insulator-metal-insulator stack (a tetrode or four electrode lens), and the bottom of each well 302 may comprise a base electrode. The voltage applied to each base electrode is individually controllable to achieve ON or OFF reflective states. FIG. 4A is a schematic diagram showing incident and reflected electron rays in a first mode of operation of a switchable multiple-electrode electron reflector with a flat base electrode in accordance with an embodiment of the invention. This mode of operation is referred to above as reflective Mode A. The incident electron rays 402 within a multiple-electrode well are shown on the left side of the diagram, and the reflected electron rays 404 within the same multiple-electrode well are shown on the right side of the diagram. As seen, in this mode, for incident electron rays 402 which are parallel at the entrance of the well 403, the reflected electron rays 404 are also substantially parallel at the exit of the well 405. FIG. 4B is a schematic diagram showing incident and reflected electron rays in a second mode of operation of a switchable multiple-electrode electron reflector with a flat base in accordance with an embodiment of the invention. This mode of operation is referred to above as reflective Mode B. The incident electron rays 402 within a multiple-electrode well are shown on the left side of the diagram, and the reflected electron rays 406 within the same multiple-electrode well are shown on the right side of the diagram. As seen, in this mode, for incident electron rays 402 which are parallel at the entrance of the well 403, the reflected electron rays 406 are also substantially divergent at the exit of the well 407. In accordance with an embodiment of the present invention, a substantial portion of the reflected electron rays 404 in Mode A passes through the pupil aperture of the projection electron-optics and impinge upon a wafer being patterned. Meanwhile, only a very small portion of these reflected electron rays 406 in Mode B passes through the pupil aperture of the projection electron-optics and impinge upon a wafer being patterned. Note that, in FIGS. 4A and 4B, it is assumed that the incident electrons have a relatively small energy spread, for example, of less than one electron volt (<1.0 eV). In this case, a substantially larger energy spread in the incident electrons would result in the reflected electron rays having greater angular spread in their trajectories, and hence a substantially smaller portion of the reflected electron rays 404 in Mode A would pass through the pupil aperture of the projection electron-optics. FIG. 5 is a three-dimensional (3D) design of a switchable multiple-electrode electron reflector with a flat base electrode in accordance with an embodiment of the invention. The 3D design shows the flat base electrode 320 and four stacked electrodes (Electrode 1 311, Electrode 2 312, Electrode 3 313, Electrode 314). FIG. 6 is a ray tracing diagram depicting the trajectories of electrons from a point source as the electrons are reflected from a switchable multiple-electrode electron reflector with a flat base electrode in accordance with an embodiment of the invention. Shown on the left side of the diagram are trajectories of electrons from a point source 602 as the electrons are reflected from the multiple-electrode electron reflector. The rays in the diagram show the electron trajectories as the electrons leave the point source 602, pass through the top 311, upper 312, middle 313, and lower 314 electrodes, and are reflected by the base (bottom) electrode 320. Shown on the right side of the diagram is a virtual mirror image of the left side. The paraxial reflected paths of the first 604 and second 606 rays have been unfolded so that the left side represents the incoming rays and the right side represents the reflected rays. The region in between P and P′ represents the region near the micro electrostatic mirror (base electrode 320). As seen, the first 604 and second 606 rays remain parallel in the region in between P and P′, while they become skew outside of that region (see 610). That the two rays are not paraxial upon exit shows the occurrence of substantial chromatic aberration. Such aberration limits the use of the electron reflector with a flat base electrode to a beam of limited energy spread (in order to avoid severe aberration), and therefore limits beam current and reduces system throughput. FIG. 7 is a cross-sectional diagram of a switchable multiple-electrode electron reflector for a pixel of a dynamic pattern generator in accordance with an alternate embodiment of the invention. The reflector shown in FIG. 7 is similar to the reflector shown in FIG. 3A. The difference between the two is that the base electrode 720 in the reflector of FIG. 7 is concave, while the base electrode 320 in the reflector of FIG. 3A is flat. In one embodiment, voltages applied to the electrodes for a reflector with a concave base electrode may be as follows. Positive 5 volts for Electrode 1 311, positive 13.2 volts for Electrode 2 312, positive 18.2 volts for Electrode 3 313, and positive 0.4 volts for Electrode 4 314. For the concave base electrode 720, negative 5.2 volts (−5.2 V) may be applied for Mode A, and negative 3.7 volts (−3.7V) may be applied for Mode B. Note that the above example voltages applied to the electrodes are provided for illustrative purposes. The voltages applied in an actual system will vary depending on the implementation. For instance, while the voltage on the base electrode is increased by 1.5 volts to go from Mode A to Mode B in the above-described implementation, decreasing the voltage on the base electrode by 1.5 volts may also work to go from Mode A to Mode B in another implementation. FIG. 8 depicts a three-dimensional (3D) design of a switchable multiple-electrode electron reflector with a concave base electrode in accordance with an alternate embodiment of the invention. The 3D design shows the concave base electrode 720 and four stacked electrodes (Electrode 1 311, Electrode 2 312, Electrode 3 313, Electrode 314). FIG. 9 is a ray tracing diagram depicting the trajectories of electrons from a point source as the electrons are reflected from a switchable multiple-electrode electron reflector with a concave base electrode in accordance with an embodiment of the invention. Similar to FIG. 6, shown on the left side of the diagram are trajectories of electrons from a point source 602 as the electrons are reflected from the multiple-electrode electron reflector. The rays in the diagram show the electron trajectories as the electrons leave the point source 602, pass through the top 311, upper 312, middle 313, and lower 314 electrodes, and are reflected by the base (bottom) electrode 720. In this embodiment, the base electrode 720 is a concave electrode. Shown on the right side of the diagram is a virtual mirror image of the left side. The paraxial reflected paths of the first 904 and second 906 rays have been unfolded so that the left side represents the incoming rays and the right side represents the reflected rays. The region in between P and P′ represents the region near the micro electrostatic mirror (base electrode 720). In this case, the concave shape of the base electrode 720 effectively adds the illustrated converging lens (in comparison to the flat base electrode 320). The electron ray tracing shows that the first 904 and second 906 rays are parallel when they exit from the well (see 910). This is because the focusing action of the concave base electrode 720 and the top electrode 311 now compensate for the divergent effect therebetween (caused by the combined effect of the other electrodes). That the two rays are paraxial upon exit shows the absence of substantial chromatic aberration. This absence enables the use of a beam with wider energy spread and thereby enables increased beam current and higher system throughput. FIG. 10 is a graph of pixel yield versus energy spread for three multiple-electrode electron reflector designs: a first design with a flat base electrode; a second design with a concave (curved) base electrode and 1 micron thick insulator (dielectric) layers between the stacked electrodes; and a third design with a concave (curved) base electrode and 0.5 micron thick insulator (dielectric) layers between the stacked electrodes. The pixel yields are obtained from simulations. As shown, the pixel yield is between 50% to 60% for each design when the energy spread of the incident beam is less than 1.0 electron volt (eV). As the energy spread increases, the pixel yield remains substantially higher for the second and third designs with the concave base electrode than for the first design with the flat base electrode. Such that, when the energy spread is over 2.0 eV, the pixel yield is over 10% higher for the designs with the concave base electrode. This advantageously higher pixel yield appears to be due to the afocal and achromatic relay micro lens formed by the multiple-electrode reflector with concave base electrode as disclosed herein. The afocal condition is advantageous in order not to exceed the numerical aperture of the system. The on/off switching of this micro device is obtained by forming the afocal condition to achieve the on state and breaking the afocal condition to achieve the off state. FIG. 11A is a schematic diagram showing incident and reflected electron rays in a first mode of operation of a switchable multiple-electrode electron reflector with a concave base electrode in accordance with an embodiment of the invention. This mode of operation is referred to above as reflective Mode A. The incident electron rays 1102 within a multiple-electrode well are shown on the left side of the diagram, and the reflected electron rays 1104 within the same multiple-electrode well are shown on the right side of the diagram. As seen, in this mode, for incident electron rays 1102 which are parallel at the entrance of the well 1103, the reflected electron rays 1104 are also substantially parallel at the exit of the well 1105. FIG. 11B is a schematic diagram showing incident and reflected electron rays in a second mode of operation of a switchable multiple-electrode electron reflector with a flat base in accordance with an embodiment of the invention. This mode of operation is referred to above as reflective Mode B. The incident electron rays 1102 within a multiple-electrode well are shown on the left side of the diagram, and the reflected electron rays 1106 within the same multiple-electrode well are shown on the right side of the diagram. As seen, in this mode, for incident electron rays 1102 which are parallel at the entrance of the well 1103, the reflected electron rays 1106 are also substantially divergent at the exit of the well 1107. In FIGS. 11A and 11B, it is assumed that the incident electrons have a relatively large spread, for example, of greater than two electron volts (>2.0 eV). Advantageously, despite a substantially larger energy spread in the incident electrons, the reflector still operates effectively as an on/off switch using modes NB. This is due to the concave base electrode 720 reducing the chromatic aberration of the reflector. Hence, despite the larger energy spread, a substantial portion of the reflected electron rays 1104 in Mode A passes through the pupil aperture of the projection electron-optics and impinge upon a wafer being patterned. Meanwhile, only a very small portion of these reflected electron rays 1106 in Mode B passes through the pupil aperture of the projection electron-optics and impinge upon a wafer being patterned. FIG. 12 is a schematic diagram of a maskless reflection electron beam projection lithography system 1200 in accordance with an embodiment of the invention. The name may be abbreviated to a reflection electron beam lithography or REBL system. As depicted in FIG. 12, the system 1200 includes an electron source 1202, illumination electron-optics 1204, a separator 1206, an objective electron lens 1210, a dynamic pattern generator (DPG) 1212, projection electron-optics 1214, and a stage 1216 for holding a wafer or other target to be lithographically patterned. In accordance with an embodiment of the invention, the various components of the system 1200 may be implemented as follows. The electron source 1202 may be implemented so as to supply a large current at low brightness (current per unit area per solid angle) over a large area. The large current is to achieve a high throughput rate. Preferably, the material of the source 1202 will be capable of providing a brightness of about 104 or 105 A/cm2 sr (Amperes per cm2 steradian). One implementation uses LaB6, a conventional electron emitter, which typically have a brightness capability of about 106 A/cm2 sr, as the source material. Another implementation uses tungsten dispenser emitters, which typically have a brightness capability of about 105 A/cm2 sr when operating at 50 kilovolts, as the source material. Other possible emitter implementations include a tungsten Schottky cathode, or heated refractory metal disks (i.e. Ta). The electron source 1202 may be further implemented so as to have a low energy spread. The REBL system 1200 should preferably control the energy of the electrons so that their turning points (the distance above the DPG 1212 at which they reflect) are relatively constant, for example, to within about 100 nanometers. To keep the turning points to within about 100 nanometers, the electron source 1202 would preferably have an energy spread no greater than 0.5 electron volts (eV). LaB6 emitters have typical energy spreads of 1 to 2 eV, and tungsten dispenser emitters have typical energy spreads of 0.2-0.5 eV. In accordance with one embodiment of the invention, the source 1202 comprises a LaB6 source or tungsten Schottky emitter that is operated a few hundred degrees C. below its normal operating temperature to reduce the energy spread of the emitted electrons. However, cooler operating temperatures can destabilize the source 1202, for example, due to impurities settling on the source surface and thereby diminishing its reliability and stability. Therefore, the source material may be preferably selected to be a material in which impurities are unlikely to migrate to the surface and choke off emission. Moreover, the vacuum on the system may be made stronger to overcome the impurity problem. Conventional lithography systems operate at a vacuum of 10−6 Torr. A scanning electron microscope (SEM) with a LaB6 source typically operates at 10−7 Torr. A SEM with a Schottky emitter typically operates at 10−9 Torr or better in the gun region. In accordance with one implementation, the REBL operates with a gun region vacuum of 10−9 Torr or lower to protect the stability of the source 1202. The illumination electron-optics 1204 is configured to receive and collimate the electron beam from the source 1202. The illumination optics 1204 allows the setting of the current illuminating the pattern generator structure 1212 and therefore determines the electron dose used to expose the substrate. The illumination optics 1204 may comprise an arrangement of magnetic and/or electrostatic lenses configured to focus the electrons from the source 1202. The specific details of the arrangement of lenses depend on specific parameters of the apparatus and may be determined by one of skill in the pertinent art. A separator 1206 may be configured to receive the incident beam 1205 from the illumination optics 1204. In one implementation, the separator 1206 comprises a magnetic prism. When the incident beam traverses the magnetic fields of the prism, a force proportional to the magnetic field strengths acts on the electrons in a direction perpendicular to their trajectory (i.e. perpendicular to their velocity vectors). In particular, the trajectory of the incident beam 1205 is bent towards the objective lens 1210 and the dynamic pattern generator 1212. In one implementation, the magnetic prism may be configured with a non-uniform magnetic field so as to provide stigmatic focusing, for example, as disclosed in U.S. Pat. No. 6,878,937 to Marion Mankos, entitled “Prism Array for Electron Beam Inspection and Defect Review.” Below the separator 1206, the electron-optical components of the objective optics are common to the illumination and projection subsystems. The objective optics may be configured to include the objective lens 1210 and one or more transfer lenses (not shown). The objective optics receives the incident beam from the separator 1206 and decelerates and focuses the incident electrons as they approach the DPG 1212. The objective optics is preferably configured (in cooperation with the gun 1202, illumination optics 1204, and separator 1206) as an immersion cathode lens and is utilized to deliver an effectively uniform current density (i.e. a relatively homogeneous flood beam) over a large area in a plane above the surface of the DPG 1212. In one specific implementation, the objective lens 1210 may be implemented to operate with a system operating voltage of 50 kilovolts. Other operating voltages may be used in other implementations. The dynamic pattern generator 1212 comprises an array of pixels. Each pixel may comprise a multiple-electrode electron reflector to which voltage levels are controllably applied. The extraction part of the objective lens 1210 provides an extraction field in front of the DPG 1212. As the electrons reflected in the first reflective mode 1213 leave the DPG 1212, the objective optics is configured to accelerate the reflected electrons 1213 toward their second pass through the separator 1206. The separator 1206 is configured to receive the reflected electrons 1213 from the transfer lens 1208 and to bend the trajectories of the reflected electrons towards the projection optics 1214. The projection electron-optics 1214 reside between the separator 1206 and the wafer stage 1216. The projection optics 1214 is configured to focus the electron beam and demagnify the beam onto photoresist on a wafer or onto another target. The demagnification may range, for example, from 1× to 20× demagnification (i.e. 1× to 0.05× magnification). The blur and distortion due to the projection optics 1214 is preferably a fraction of the pixel size. In one implementation, the pixel size may be, for example, 22.5 nanometers (nm). In such a case, the projection optics 1214 preferably has aberrations and distortions of less than 10-20 nm. The wafer stage 1216 holds the target wafer. In one embodiment, the stage 1216 is stationary during the lithographic projection. In another embodiment, the stage 1216 is in linear motion during the lithographic projection. In the case where the stage 1216 is moving, the pattern on the DPG 1212 may be dynamically adjusted to compensate for the motion such that the projected pattern moves in correspondence with the wafer movement. In other embodiments, the REBL system 1200 may be applied to other targets besides semiconductor wafers. For example, the system 1200 may be applied to reticles. The reticle manufacturing process is similar to the process by which a single integrated circuit layer is manufactured. FIG. 13 is a schematic diagram of a maskless reflection electron beam projection lithography system 1300 showing further components in accordance with an embodiment of the invention. The additional components illustrated include a high voltage source 1302, a parallel datapath 1304, an interferometer 1306, a height sensor 1308, feedback circuitry 1310, and beam deflectors 1312. The high voltage source 1302 is shown as providing a high voltage to the source 1202 and to the DPG 1212. The voltage provided may be, for example, 50 kilovolts. The parallel data path 1304 is configured to carry control signals to the DPG 1212 for controlling the voltage on each pixel (so that it reflects electrons in a first reflective mode or a second reflective mode). In one embodiment, the control signals are adjusted so that the pattern moves electronically across the DPG pixel array in a manner that is substantially the same as the way signals move through a shift register and at a rate so as to match the linear movement of the wafer. In this embodiment, each exposed point on the wafer may receive electrons reflected in the first reflective mode from an entire column (or row) of DPG pixels, integrated over time. In one implementation of this embodiment, the DPG 1212 is configured to resemble a static random access memory (SRAM) circuit. In another embodiment, the control signals are such that the DPG 1212 exposes one complete frame at a time. In this embodiment, each pixel on the DPG 1212 exposes a corresponding pixel on the wafer. The pattern on the DPG 1212 remains constant during the exposure of each frame. In one implementation of this embodiment, the DPG 1212 is configured to resemble a dynamic random access memory (DRAM) circuit. The interferometer 1306 may be included to provide tight coupling and positional feedback between the electron beam location and the target on the wafer. In one embodiment, the optical beams are reflected off mirrors on the stage. The resulting interference pattern depends on the difference of the individual beam paths and allows accurate measurement of the stage and wafer position. Vertical positional information may be provided by a height sensor 1308. The positional information may be fed back via feedback circuitry 1310 so as to control beam deflectors 1312. The deflectors 1312 are configured to deflect the projected beam so as to compensate for vibrations and positional drift of the wafer. While FIGS. 12 and 13 depict an example system within which an embodiment of the invention may be implemented, embodiments of the invention may be implemented within other systems as well. For example, an embodiment of the invention may be implemented within a system which is configured with a Wien filter, rather than a magnetic prism separator. In such an embodiment, the incident electron beam would pass straight through the Wien filter to the DPG, and the portions of the beam that are reflected in a focused manner from the DPG would be deflected at an angle by the Wien filter to impinge upon the target substrate. In other embodiments, the multiple-electrode electron reflectors disclosed may be configured within an apparatus other than an electron beam lithography instrument. The above-described diagrams are not necessarily to scale and are intended be illustrative and not limiting to a particular implementation. In the above description, numerous specific details are given to provide a thorough understanding of embodiments of the invention. However, the above description of illustrated embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise forms disclosed. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific details, or with other methods, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the invention. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
054188326	abstract	A scanning radiographic system having reduced scatter and improved tube loading employs a pre-patient slit to form the x-ray beam into a fan beam and a post-patient slot to eliminate scattered rays from the fan beam. A grid incorporated into the slot permits a further reduction of scatter sufficient to employ a wider slot without detrimental increase in scatter but with significant improvement in tube loading. The lamellae of the grid proceed diagonally across the width of the slot to reduce grid lines and are tipped to focus on the focal spot of the x-ray source.
043943454	summary	BACKGROUND OF THE INVENTION This invention relates to the ultrasonic examination of jet pump beams in nuclear reactors by an ultrasonic test apparatus including a carriage holding ultrasonic transducers, which is lowered into the "reactor" as will be discussed herein. Certain types of nuclear reactors employ as many as twenty downwardly directed jet pumps to circulate reactor water through the core of the reactor vessel during operation. Jet pumps receive driving water from an inlet riser and through a pipe elbow connecting the inlet riser to the jet pump nozzle, as is shown for example in U.S. Pat. Nos. 3,378,456 and 3,389,055, both assigned to General Electric Company. Each pipe elbow is held in position by a jet pump beam, which will be described in substantial detail hereinafter. The static and dynamic load on jet pump beams including vibrations imposed during reactor operation has been found to cause, in some instances, beam cracking that begins in the upper central portion of the beams. Each jet pump beam holds in place a pipe elbow, which leads reactor water from an inlet riser pipe toward a jet pump nozzle. Cracking in a jet pump beam threatens the release of a pipe elbow from its normal position, which would impair proper jet pump operation. Accordingly, it is desirable to determine the physical integrity of jet pump beams on a regular basis, as for example by ultrasonic examination. This could be done by dismantling the jet pump beams from the reactor and transporting them to a laboratory for testing. On the other hand, the ultrasonic method and apparatus disclosed herein may instead conveniently be employed for on-site inspection of the jet pump beams within the reactor vessel. Accordingly, it is an object of this invention to provide test apparatus for ultrasonically examining jet pump beams without requiring their removal from the reactor vessel. Another object of this invention is to provide an ultrasonic test apparatus that eliminates the need to physically handle and transport jet pump beams for ultrasonic testing and thereby reduces radiation exposure to the personnel performing the test. SUMMARY OF THE INVENTION These and other objects of the invention are achieved by providing a method and apparatus for ultrasonic detection of cracking in jet pump beams of a nuclear reactor. The apparatus holds ultrasonic transducers in position on a carriage lowered onto a jet pump beam to be examined. The carriage is remotely positioned onto the beam by maneuvering a pole connected to the carriage. Electric leads connect each of the ultrasonic transducers to a switching mechanism located external to the reactor vessel. The apparatus includes the switching mechanism and also a signal generator, receiver, and visual display. The method of using the apparatus involves directing a generated electric signal through the switching mechanism to a transducer mounted near the jet pump beam. The transducer converts the electric signal into an ultrasonic signal, which travels to an examination zone potentially containing cracks. Such cracks reflect or obstruct the passage of ultrasound. In one mode of operation, the sending transducer receives reflections from cracks. In another mode, an obstruction preventing reception of the transmitted signal indicates cracking.
053655559	claims	1. A system for measuring water level comprising: a reactor pressure vessel containing a nuclear reactor core and a steam separator assembly disposed thereabove, said vessel being fillable with water to a nominal level above said core; a reference leg for containing a predetermined first reference column height of water having a reference level disposed vertically above said nominal level; a first variable leg having a first tap disposed in flow communication with said vessel at a predetermined first depth below said reference level and below said nominal level and adjacent said steam separator assembly, and further having a first port; a first monitor disposed in flow communication with said reference leg and said first port for determining differential pressure therebetween to indicate level of said water in said vessel above said first tap; a second variable leg having a second tap disposed in flow communication with said vessel at a predetermined second depth below said reference level, said nominal level, and said first tap, and further having a second port; and a second monitor disposed in flow communication with said first leg and said second port for determining differential pressure therebetween to indicate level of said water between said first and second taps when said water level falls below said first tap, with said first leg being inclined downwardly for containing water therein up to said first tap to provide a predetermined second reference column height for said second monitor. a steam leg having an inlet port disposed in flow communication with said vessel above said first tap and said nominal level, and further having an outlet port; and a condensing chamber having an inlet disposed in flow communication with said steam leg outlet port for receiving steam therethrough from said vessel to form condensate in said chamber, and an outlet disposed in flow communication with said reference leg for discharging thereto said condensate. a third variable leg having a third tap disposed in flow communication with said vessel at a predetermined third depth below said reference level and said first tap, and above said second tap, and further having a third port; and a third monitor disposed in flow communication with said reference leg and said third port for determining differential pressure therebetween to indicate level of said water in said vessel above said third tap. first, second and third taps arranged in flow communication with the inside of said reactor pressure vessel, said first tap being located at a height higher than said predetermined height, said second tap being located at a height lower than said predetermined height and adjacent to said steam separator assembly, and said third tap being located at a height lower than the height of said second tap; a steam leg having a lower port at one end in flow communication with said first tap and an upper port at the other end, said lower port of said steam leg being located at a height lower than a height of said upper port of said steam leg; and means for condensing steam passing through said steam leg into water, said steam condensing means being in flow communication with said upper port of said steam leg; a reference leg having an upper port at one end in flow communication with said steam condensing means and a lower port at the other end, said lower port of said reference leg being located at a height lower than a height of said upper port of said reference leg, said reference leg being fillable with water to a reference level located at a height higher than said predetermined height; a first variable leg having an upper port at one end in flow communication with said second tap and a lower port at the other end, said lower port of said first variable leg being located at a height lower than a height of said upper port of said first variable leg; a second variable leg having an upper port at one end in flow communication with said third tap and a lower port at the other end, said lower port of said second variable leg being located at a height lower than a height of said upper port of said second variable leg; a first extension leg having an upper port at one end in flow communication with said first variable leg and a lower port at the other end, said lower port of said first extension leg being located at a height lower than a height of said upper port of said first extension leg; a first differential pressure monitor having a first input in flow communication with said lower port of said reference leg and a second input in flow communication with said lower port of said first variable leg; and a second differential pressure monitor having a first input in flow communication with said lower port of said extension leg and a second input in flow communication with said lower port of said second variable leg. a fourth tap arranged in flow communication with the inside of said reactor pressure vessel, said fourth tap being located at a height lower than said predetermined height and higher than the height of said third tap; a third variable leg having an upper port at one end in flow communication with said fourth tap and a lower port at the other end, said lower port of said third variable leg being located at a height lower than a height of said upper port of said third variable leg; a second extension leg having an upper port at one end in flow communication with said reference leg and a lower port at the other end, said lower port of said second extension leg being located at a height lower than a height of said upper port of said second extension leg; and a third differential pressure monitor having a first input in flow communication with said lower port of said second extension leg and a second input in flow communication with said lower port of said third variable leg. a third extension leg having an upper port at one end in flow communication with said third variable leg and a lower port at the other end, said lower port of said third extension leg being located at a height lower than a height of said upper port of said third extension leg; a fourth extension leg having an upper port at one end in flow communication with said first extension leg and a lower port at the other end, said lower port of said fourth extension leg being located at a height lower than a height of said upper port of said fourth extension leg; and a fourth differential pressure monitor having a first input in flow communication with said lower port of said third extension leg and a second input in flow communication with said lower port of said fourth extension leg. first and second taps arranged in flow communication with the inside of said reactor pressure vessel, said first tap being located at a height lower than said predetermined height and adjacent to said steam separator assembly, and said second tap being located at a height lower than the height of said first tap; a reference leg having an upper port at one end and a lower port at the other end, said lower port of said reference leg being located at a height lower than a height of said upper port of said reference leg, said reference leg being fillable with water to a reference level located at a height higher than said predetermined height; a first variable leg having an upper port at one end in flow communication with said first tap and a lower port at the other end, said lower port of said first variable leg being located at a height lower than a height of said upper port of said first variable leg; a second variable leg having an upper port at one end in flow communication with said second tap and a lower port at the other end, said lower port of said second variable leg being located at a height lower than a height of said upper port of said second variable leg; a first extension leg having an upper port at one end in flow communication with said first variable leg and a lower port at the other end, said lower port of said first extension leg being located at a height lower than a height of said upper port of said first extension leg; a first differential pressure monitor having a first input in flow communication with said lower port of said reference leg and a second input in flow communication with said lower port of said first variable leg; and a second differential pressure monitor having a first input in flow communication with said lower port of said extension leg and a second input in flow communication with said lower port of said second variable leg. a third tap arranged in flow communication with the inside of said reactor pressure vessel, said third tap being located at a height higher than said predetermined height; a steam leg having a lower port at one end in flow communication with said third tap and an upper port at the other end, said lower port of said steam leg being located at a height lower than a height of said upper port of said steam leg; and means for condensing steam passing through said steam leg into water, said steam condensing means being in flow communication with said upper port of said steam leg and with said upper port of said reference leg. a fourth tap arranged in flow communication with the inside of said reactor pressure vessel, said fourth tap being located at a height lower than said predetermined height and higher than the height of said second tap; a third variable leg having an upper port at one end in flow communication with said fourth tap and a lower port at the other end, said lower port of said third variable leg being located at a height lower than a height of said upper port of said third variable leg; a second extension leg having an upper port at one end in flow communication with said reference leg and a lower port at the other end, said lower port of said second extension leg being located at a height lower than a height of said upper port of said second extension leg; and a third differential pressure monitor having a first input in flow communication with said lower port of said second extension leg and a second input in flow communication with said lower port of said third variable leg. a third extension leg having an upper port at one end in flow communication with said third variable leg and a lower port at the other end, said lower port of said third extension leg being located at a height lower than a height of said upper port of said third extension leg; a fourth extension leg having an upper port at one end in flow communication with said first extension leg and a lower port at the other end, said lower port of said fourth extension leg being located at a height lower than a height of said upper port of said fourth extension leg; and a fourth differential pressure monitor having a first input in flow communication with said lower port of said third extension leg and a second input in flow communication with said lower port of said fourth extension leg. 2. A system according to claim 1 further comprising: 3. A system according to claim 2 wherein said first tap is disposed above said core, and said second tap is disposed below said core. 4. A system according to claim 3 further comprising: 5. A system according to claim 4 wherein said third tap is disposed adjacent the top of said core and said second tap so that said first monitor indicates said water level from said nominal level down to about said first tap, said third monitor indicates said water level from said nominal level down to about said third tap, and said second monitor indicates said water level from about said first tap down to about said second tap. 6. A system according to claim 5 further comprising a fourth monitor disposed in flow communication between said first and third legs for determining differential pressure therebetween to indicate level of said water in said vessel between said first and third taps when said water level falls below said first tap. 7. A system for measuring the level of water inside a reactor pressure vessel containing a fuel core and a steam separator assembly arranged above said fuel core, said reactor pressure vessel having a normal water level at a predetermined height between said steam separator assembly and said fuel core, comprising: 8. The system as defined in claim 7, wherein said third tap is located at a height lower than said core. 9. The system as defined in claim 7, further comprising: 10. The system as defined in claim 9, further comprising: 11. A system for measuring the level of water inside a reactor pressure vessel containing a fuel core and a steam separator assembly arranged above said fuel core, said reactor pressure vessel having a normal water level at a predetermined height between said steam separator assembly and said fuel core, comprising: 12. The system as defined in claim 11, further comprising: 13. The system as defined in claim 11, wherein said second tap is located at a height lower than said core. 14. The system as defined in claim 11, further comprising: 15. The system as defined in claim 14, further comprising:
052590097	summary	BACKGROUND OF THE INVENTION The invention relates to nuclear fuel rod assemblies for water reactors, and more particularly to a fuel rod spacer arrangement for boiling water reactors wherein the fuel rods are supported within an outer channel in a spaced and aligned fashion relative to one another. OBJECTS OF THE INVENTION It is an object of the invention to provide a nuclear fuel rod assembly for a boiling water reactor wherein a spacer assembly is provided which is of simple construction, yet provides a secure retention, alignment, and spacing for the nuclear fuel rods. It is another object of the invention to provide a spacer system wherein the fuel rods can be easily loaded. It is another object of the invention to provide a spacer system wherein moderator can flow freely therethrough. It is a further object of the invention to create a turbulent flow so that coolant contact with the fuel rods is maximized and steam bubble contact with the fuel rods is minimized. It is a further object of the invention to provide a spacer system which can be easily assembled. It is another object of the invention to provide a spacer system which will not be substantially affected by irradiation. SUMMARY OF THE INVENTION According to the invention, a boiling water reactor fuel rod assembly is provided wherein a spacer system is formed of a plurality of spaced apart and parallel spacer strips. Each of the spacer strips has a plurality of corrugations. Corrugations of adjacent spacer strips are reversed relative to one another so as to create support cells for receiving fuel rods between the opposed corrugations. The spacer strips are constructed of a spring-action or resilient material such that prior to loading of the fuel rods, there is an unloaded displaced position of at least some of the corrugations. When a fuel rod is loaded into a cell, the fuel rod forces the portions of the spacer strip which are in their unloaded displaced position into a loaded position. Preferably, pairs of spacer strips are provided having their corrugations abutting each other back-to-back, with every other corrugation along the spacer strips being welded to one another. The unwelded corrugations can then attain by spring action the unloaded displaced position, with the corrugations then being spaced apart from one another. Preferably the spacer strips are arranged to form a lattice or grid, with two of such lattices being positioned one above the other to form a rod spacer. A plurality of the rod spacers are provided at desired spaced intervals from top to bottom along the fuel rod assembly.
	claims	1. A proximity X-ray exposure apparatus for irradiating a reticle with X-rays generated from an X-ray source and irradiating a substrate with X-rays that have passed through the reticle, said apparatus comprising: a plasma X-ray source for generating X-rays by producing plasma; and control means for controlling X-ray intensity distribution by controlling production of the plasma so that the plasma is produced at a plurality of positions in one irradiating operation of the substrate with the X-rays, wherein said control means controls the X-ray intensity distribution in order to control the plurality of positions so that a required amount of defocusing, which is a size of a projection image corresponding to one point on the reticle formed by irradiating the reticle with X-rays generated at the plurality of positions, can be obtained. 2. The apparatus according to claim 1 , further comprising: claim 1 a target for functioning as the X-ray source by generating X-rays in response to being irradiated with laser light, wherein said control means controls operation for irradiating with laser light a plurality of locations within a laser-light irradiation area on said target that has been decided based upon the amount of defocusing of X-rays, the defocusing amount representing a stage of X-ray intensity distribution and being decided based upon importance of critical resolution and linearity between the mask pattern and the resist pattern. 3. The apparatus according to claim 2 , wherein the irradiation area is decided based upon a value r obtained from claim 2 xcex4xc3x97L/g where xcex4 represents the amount of defocusing which represents a standard deviation of the X-ray intensity distribution, L the distance between said target and the reticle, and g the distance between the reticle and the substrate. 4. The apparatus according to claim 3 , wherein the irradiation area is decided to be an area having a radius of 2r, and claim 3 1.5 nmxc3x97 L/g less than r less than 0.5xc3x97 Wrxc3x97L/g where L represents the distance between the X-ray source and the reticle, g the distance between the reticle and the wafer, and Wr the least line width. said control means controls operation for irradiating the irradiation area on said target with laser light in such a manner that irradiation density becomes a normal distribution having a standard deviation r which satisfies the following inequality, 5. The apparatus according to claim 3 , wherein the irradiation area is decided to be an area having a radius of rxc3x97{square root over (3)}, and claim 3 6 nmxc3x97 L/g less than D less than 2xc3x97 Wrxc3x97L/g where L represents the distance between the X-ray source and the reticle, g the distance between the reticle and the wafer, and Wr the least line width. said control means controls operation for irradiating the irradiation area on said target with laser light in such a manner that irradiation density becomes uniform, the irradiation area has a diameter D which satisfies the following inequality, 6. The apparatus according to claim 2 , further comprising setting means for setting the amount of defocusing. claim 2 7. The apparatus according to claim 2 , wherein said target generates X-rays by producing plasma in response to being irradiated with laser light. claim 2 8. The apparatus according to claim 2 , wherein said X-ray source has a mirror for reflecting the laser light in order that the laser light will arrive at said target, and claim 2 said control means controls operation for irradiating with laser light a plurality of locations within the irradiation area on said target by changing the angle of said mirror during a single exposure operation. 9. The apparatus according to claim 2 , wherein the X-ray source has a plurality of laser light sources for generating a plurality of laser beams for irradiating respective ones of different positions on said target, and claim 2 said control means controls operation for irradiating with laser light a plurality of locations within the irradiation area on said target by using a plurality of laser beams from said plurality of laser light sources during a single exposure operation. 10. The apparatus according to claim 1 , wherein said plasma X-ray source produces plasma by applying pulse voltages between electrodes. claim 1 11. The apparatus according to claim 10 , wherein the plasma is moved by a magnetic field. claim 10 12. The apparatus according to claim 10 , wherein the plasma is moved by an electric field. claim 10 13. The apparatus according to claim 10 , wherein the plasma is moved by moving the electrodes. claim 10 14. The apparatus according to claim 1 , further comprising a display, a network interface and a computer for running network software, claim 1 wherein maintenance information concerning said X-ray exposure apparatus is communicated by data communication via a computer network. 15. The apparatus according to claim 14 , wherein the network software is connected to an external network of a plant at which said X-ray exposure apparatus has been installed, said display is provided with a user interface for accessing a maintenance database provided by a vendor or user of said X-ray exposure apparatus, and information is obtained from said database via said external network. claim 14 16. A method of manufacturing devices, comprising steps of: placing a plurality of items of semiconductor manufacturing equipment, inclusive of an X-ray exposure apparatus, in a plant; and manufacturing a semiconductor device using the plurality of items of semiconductor manufacturing equipment, wherein the X-ray exposure apparatus irradiates a reticle with X-rays generated from an X-ray source and irradiates a substrate with X-rays that have passed through the reticle to thereby transfer a pattern on the reticle to the substrate, the apparatus having: (i) a plasma X-ray source for generating X-rays by producing plasma; and (ii) control means for controlling production of the plasma so that the plasma is produced at a plurality of positions in one irradiating operation of the substrate with X-rays, wherein the control means controls the X-ray intensity distribution in order to control the plurality of positions so that a required amount of defocusing, which is a size of a projection image corresponding to one point on the reticle formed by irradiating the reticle with X-rays generated at the plurality of positions, can be obtained. 17. The method according to claim 16 , further comprising the steps of: claim 16 connecting the plurality of items of semiconductor manufacturing equipment by a local-area network; connecting the local-area network and an external network outside the plant; acquiring information concerning the X-ray exposure apparatus from a database on the external network utilizing said local-area network and said external network; and controlling the X-ray exposure apparatus based upon the information acquired. 18. The method according to claim 17 , wherein maintenance information for the manufacturing equipment is obtained by accessing, by data communication via the external network, a database provided by a vendor of the manufacturing equipment or by a user, or production management is performed by data communication with a semiconductor manufacturing plant other than the first mentioned semiconductor manufacturing plant via the external network. claim 17 19. A method of maintaining an X-ray exposure apparatus, the method comprising the steps of: preparing a database, which stores information relating to maintenance of the X-ray exposure apparatus, on an external network outside a plant at which the X-ray exposure apparatus has been installed; connecting the X-ray exposure apparatus to a local-area network inside the plant; and maintaining the X-ray exposure apparatus, based upon information that has been stored in the database, utilizing the external network and the local-area network, wherein the X-ray exposure apparatus irradiates a reticle with X-rays generated from an X-ray source and irradiates a substrate with X-rays that have passed through the reticle to thereby transfer a pattern on the reticle to the substrate, the apparatus having: (i) a plasma X-ray source for generating X-rays by producing plasma; (ii) control means for controlling of production of the plasma so that the plasma is produced at a plurality of positions in one irradiating operation at the substrate with X-rays, wherein the control means controls the X-ray intensity distribution in order to control the plurality of positions so that a required amount of defocusing, which is a size of a projection image corresponding to one point on the reticle formed by irradiating the reticle with X-rays generated at the plurality of positions, can be obtained. 20. A method of controlling a proximity X-ray exposure apparatus for irradiating a reticle with X-rays generated from an X-ray source and irradiating a substrate with X-rays that have passed through the reticle, the method comprising: a generating step of generating X-rays by producing plasma; and a control step of controlling X-ray intensity distribution by controlling production of the plasma so that the plasma is produced at a plurality of positions in one irradiating operation of the substrate with the X-rays, wherein said control step controls the X-ray intensity distribution in order to control the plurality of positions so that a required amount of defocusing, which is a size of a projection image corresponding to one point on the reticle formed by irradiating the reticle with X-rays generated at the plurality of positions, can be obtained. 21. The method according to claim 20 , further comprising a determining step of determining a laser-light irradiation area on a target which functions as the X-ray source by generating X-rays in response to being irradiated with laser light, based upon an amount of defocusing required for the X-rays, the amount of defocusing representing a shape of an X-ray intensity distribution and being determined based upon importance of critical resolution and linearity between the mask pattern and resist pattern, claim 20 wherein said control step controls the irradiation to irradiate with laser light a plurality of locations within the laser-light irradiation area on the target, which has been determined in said determining step. 22. The method according to claim 21 , wherein said determining step determines the irradiation region based upon a value r obtained from claim 21 xcex4xc3x97L/g where xcex4 represents the amount of defocusing which represents a standard deviation of X-ray intensity distribution, L the distance between the target and the reticle, and g the distance between the reticle and the substrate. 23. The method according to claim 22 , wherein said determining step determines the irradiation area to be an area having a radius of 2r, and claim 22 1.5 nmxc3x97 L/g less than r less than 0.5xc3x97 Wrxc3x97L/g where L represents the distance between the X-ray source and the reticle, g the distance between the reticle and the wafer, and Wr the least line width. said control step controls operation for irradiating laser light so that the irradiation area on the target is irradiated with laser light in such a manner that irradiation density becomes a normal distribution having a standard deviation r which satisfies the following inequality, 24. The method according to claim 22 , wherein said determining step determines the irradiation area to be an area having a radius of rxc3x97{square root over (3)}, and claim 22 6 nmxc3x97 L/g less than D less than 2xc3x97 Wrxc3x97L/g where L represents the distance between the X-ray source and the reticle, g the distance between the reticle and the wafer, and Wr the least line width. said control means controls operation for irradiating the irradiation area on said target with laser light in such a manner that irradiation density becomes uniform, the irradiation area has a diameter D which satisfies the following inequality, 25. The method according to claim 21 , further comprising a setting step of setting the amount of defocusing. claim 21 26. The method according to claim 21 , wherein the plasma is produced by irradiating the target with laser light, claim 21 the X-ray source has a mirror for reflecting the laser light in order that the laser light will arrive at the target, and said control step controls operation for irradiating with laser light a plurality of locations within the irradiation area on the target by changing the angle of the mirror during a single exposure operation. 27. The method according to claim 21 , wherein the plasma is produced by irradiating the target with laser light, claim 21 the X-ray source has a plurality of laser light sources for generating a plurality of laser beams for irradiating respective ones of different postitions on the target, and said control step controls operation for irradiating with laser light a plurality of locations within the irradiation area on the target by using a plurality of laser beams from the plurality of laser light sources during a single exposure operation. 28. A semiconductor manufacturing plant, comprising: a plurality of items of semiconductor manufacturing equipment inclusive of an X-ray exposure apparatus; a local-area network for interconnecting said plurality of items of manufacturing equipment; and a gateway for connecting said local-area network and an external network outside said semiconductor manufacturing plant, wherein said X-ray exposure apparatus irradiates a reticle with X-rays generated from an X-ray source and irradiates a substrate with X-rays that have passed through the reticle to thereby transfer a pattern on the reticle to the substrate, said apparatus having: (i) a plasma X-ray source for generating X-rays by producing plasma; and (ii) control means for controlling production of the plasma so that the plasma is produced at a plurality of positions in one irradiating operation of the substrate with X-rays, wherein said control means controls the X-ray intensity distribution in order to control the plurality of positions so that a required amount of defocusing, which is a size of a projection image corresponding to one point on the reticle formed by irradiating the reticle with X-rays generated at the plurality of positions, can be obtained.
047643323	summary	BACKGROUND OF THE INVENTION The hydrotesting of pipes or tubular elements, such as those found in a nuclear reactor, is often a time consuming operation and suitable sealing elements are not readily available, especially for plain end pipes without threads. In hydrotesting threaded pipes, it is, of course, possible to thread a cap on to the end of the pipe to seal the same and then subject the pipe to pressurized water. In testing of plain end pipes, however, suitable sealing elements are not available. While one type of sealing element for a plain end pipe uses a rubber expandable plug, that is inserted into the pipe to seal the same upon expansion, such as existing device does not withstand hydrotesting at high pressures, such as about 3200 pounds pre square inch gauge, that are required for certain tubular elements of nuclear reactors. In instances where leakage may occur in tubular elements of a nuclear reactor, it is highly advantageous to be able to test the tubular elements themselves, without having to subject the complete reactor vessel to such hydrotesting. It is an object of the present invention to provide a pipe end sealing element usable for hydrotesting of plain end pipes. It is another object of the present invention to provide a method for hydrotesting of a pipe in a nuclear reactor vessel which utilizes the novel pipe end sealing element. SUMMARY OF THE INVENTION A pipe end sealing element usable in hydrotesting of plain end pipes, such as those present in a nuclear reactor, comprises a cooperative hollow tubular member, hollow conical bushing of variable interior diameter, a sealing plug, and a threaded bolt. The hollow tubular member is adapted to encircle the end of the pipe and has an inwardly directed flange at one end, the flange having a bevelled surface, and a threaded interior wall at the other end. The hollow conical bushing has an inner surface engageable with the pipe outer surface, and an outer bevelled surface complementary to the bevelled surface of the hollow tubular member flange. A slot is preferably provided through the length of the hollow conical bushing to enable decreasing of the interior diameter thereof by forces acting on the outer surface. The sealing plug has a cylindrical portion insertable into the pipe, with a flange portion that rests on the end of the pipe, while the threaded bolt is engageable with the threaded portion of the hollow tubular member. The method of hydrotesting of a pipe, such as a pipe in a nuclear reactor, comprises providing the pipe end sealing element, placing the hollow tubular member over the open end of the pipe, with the threaded portion adjacent and beyond the pipe end, and inserting the hollow conical bushing into the hollow tubular member to surround the outer wall of the pipe. With the bevelled surface of the conical bushing in sliding relationship with the bevelled surface of the tubular element flange, the sealing plug is placed in the pipe with the portion thereof resting on the pipe end wall, and the threaded bolt is engaged with the tubular element threads. By advancing the threaded bolt towards the sealing plug, the hollow tubular member is pulled in an axial direction away from the pipe end, and the conical bushing is decreased in its interior diameter so as to grip the pipe outer wall, by axial sliding along the bevelled surfaces. When the seal is thus effected, a fluid is injected at a predetermined pressure into the other end of the pipe and the fluid resistant capability of the pipe determined.
	claims	1. A neutron absorber of a gray control rod, comprising a first absorber material and a second absorber material, wherein reactivity worth of the first absorber material increases as service time of the neutron absorber increases, and reactivity worth of the second absorber material decreases as the service time of the neutron absorber increases; and reactivity worth of the neutron absorber varies no more than 15% within the service time of the neutron absorber; wherein the first absorber material is metal terbium, or a compound of terbium, or an alloy comprising terbium; and the second absorber material is metal dysprosium, or a compound of dysprosium, or an alloy comprising dysprosium;wherein the first absorber material is metal terbium, terbium oxide, terbium titanate, or terbium alloy;wherein the neutron absorber is terbium-dysprosium alloy, sinter of mixture of terbium oxide and dysprosium oxide, or sinter of mixture of dysprosium titanate and terbium titanate;wherein the neutron absorber is a cylinder with diameter of D, where 1.0 mm≤D≤8.7 mm, and unit of D is millimeter; mass fraction of element terbium in the neutron absorber is x, where −0.0688×D+0.6388≤x≤−0.0026×D+0.8626; the reactivity worth of the neutron absorber varies no more than 10% within the service time of the neutron absorber. 2. The neutron absorber of the gray control rod as claimed in claim 1, wherein the neutron absorber is a cylinder with diameter of D and the mass fraction of element terbium in the neutron absorber is x, where −0.0571×D+0.7371≤x≤0.0039×D+0.7261; the reactivity worth of the neutron absorber varies no more than 5% within the service time of the neutron absorber. 3. The neutron absorber of the gray control rod as claimed in claim 1, wherein the neutron absorber is a cylinder with diameter of D, where 1.3 mm≤D≤3.3 mm. 4. The neutron absorber of the gray control rod as claimed in claim 3, wherein the neutron absorber is a cylinder with diameter of D, where 1.8 mm≤D≤3.0 mm. 5. The neutron absorber of the gray control rod as claimed in claim 4, wherein the neutron absorber is a cylinder with diameter of D, where D=2 mm; wherein the mass fraction of element terbium in the neutron absorber is x, where x=70%; the reactivity worth of the neutron absorber varies no more than 2.8% within the service time of the neutron absorber. 6. A gray control rod, comprising a cylindrical cladding tube, an upper end plug and a lower end plug for sealing two ends of the cladding tube, a neutron absorber being encapsulated in the cladding tube, wherein the neutron absorber comprises a first absorber material and a second absorber material, reactivity worth of the first absorber material increases as service time of the neutron absorber increases, reactivity worth of the second absorber material decreases as the service time of the neutron absorber increases; and reactivity worth of the neutron absorber varies no more than 15% within the service time of the neutron absorber; wherein the first absorber material is metal terbium, or a compound of terbium, or an alloy comprising terbium; and the second absorber material is metal dysprosium, or a compound of dysprosium, or an alloy comprising dysprosium. 7. The gray control rod as claimed in claim 6, wherein the neutron absorber is terbium-dysprosium alloy, sinter of mixture of terbium oxide and dysprosium oxide, or sinter of mixture of dysprosium titanate and terbium titanate. 8. The gray control rod as claimed in claim 7, wherein the neutron absorber is a cylinder with diameter of D, where 1.0 mm≤D≤8.7 mm, and unit of D is millimeter; mass fraction of element terbium in the neutron absorber is x, where −0.0688×D+0.6388≤x≤−0.0026×D+0.8626; the reactivity worth of the neutron absorber varies no more than 10% within the service time of the neutron absorber. 9. The gray control rod as claimed in claim 8, wherein the neutron absorber is a cylinder with diameter of D and the mass fraction of element terbium in the neutron absorber is x, where −0.0571×D+0.7371≤x≤0.0039×D+0.7261; the reactivity worth of the neutron absorber varies no more than 5% within the service time of the neutron absorber. 10. The gray control rod as claimed in claim 8, wherein the neutron absorber is a cylinder with diameter of D, where 1.3 mm≤D≤3.3 mm. 11. The gray control rod as claimed in claim 10, wherein the neutron absorber is a cylinder with diameter of D, where 1.8 mm≤D≤3.0 mm. 12. The gray control rod as claimed in claim 11, wherein the neutron absorber is a cylinder with diameter of D, where D=2 mm; wherein the mass fraction of element terbium in the neutron absorber is x, where x=70%; the reactivity worth of the neutron absorber varies no more than 2.8% within the service time of the neutron absorber. 13. A gray control rod assembly, comprising a plurality of gray control rods, each gray control rod comprising a cylindrical cladding tube, an upper end plug and a lower end plug for sealing two ends of the cladding tube, a neutron absorber being encapsulated in the cladding tube, wherein the neutron absorber comprises a first absorber material and a second absorber material, reactivity worth of the first absorber material increases as service time of the neutron absorber increases, reactivity worth of the second absorber material decreases as the service time of the neutron absorber increases; and reactivity worth of the neutron absorber varies no more than 15% within the service time of the neutron absorber; wherein the first absorber material is metal terbium, or a compound of terbium, or an alloy comprising terbium; and the second absorber material is metal dysprosium, or a compound of dysprosium, or an alloy comprising dysprosium. 14. The gray control rod assembly as claimed in claim 13, wherein the neutron absorber is terbium-dysprosium alloy, sinter of mixture of terbium oxide and dysprosium oxide, or sinter of mixture of dysprosium titanate and terbium titanate; the neutron absorber is a cylinder with diameter of D, where 1.0 mm≤D≤8.7 mm, and unit of D is millimeter; mass fraction of element terbium in the neutron absorber is x, where −0.0688×D+0.6388≤x≤−0.0026×D+0.8626; the reactivity worth of the neutron absorber varies no more than 10% within the service time of the neutron absorber. 15. The gray control rod assembly as claimed in claim 14, wherein the neutron absorber is a cylinder with diameter of D and the mass fraction of element terbium in the neutron absorber is x, where −0.0571×D+0.7371≤x≤0.0039×D+0.7261; the reactivity worth of the neutron absorber varies no more than 5% within the service time of the neutron absorber. 16. The gray control rod assembly as claimed in claim 14, wherein the neutron absorber is a cylinder with diameter of D, where 1.3 mm≤D≤3.3 mm. 17. The gray control rod assembly as claimed in claim 16, wherein the neutron absorber is a cylinder with diameter of D, where 1.8 mm≤D≤3.0 mm. 18. The gray control rod assembly as claimed in claim 17, wherein the neutron absorber is a cylinder with diameter of D, where D=2 mm; wherein the mass fraction of element terbium in the neutron absorber is x, where x=70%, the reactivity worth of the neutron absorber varies no more than 2.8% within the service time of the neutron absorber.
	abstract	A fuel bundle surrogate for the irradiation of a target material, having a plurality of tube sheaths, each tube sheath being parallel to a longitudinal center axis of the fuel bundle surrogate, a plurality of end caps, a pair of end plates, wherein the end plates are disposed at opposing ends of the plurality of tube sheaths, and a first target comprised of a first target material suitable for producing the isotope by way of a neutron capture event, wherein the first target is disposed in a first tube sheath, and wherein the first tube sheath of the plurality of tube sheaths comprises an elongated thickened wall portion and a pair of annular end portions, each annular end portion being disposed on a corresponding end of the thickened wall portion and having a wall thickness that is less than a wall thickness of the thickened wall portion.
	abstract	A bolt repair platform includes a frame and a tool module. The tool module includes a tool having a first end configured to rotationally engage a bolt. The tool module also includes an actuator disposed between the tool and the frame so that actuation of the actuator moves the tool with respect to the frame. The frame is removably disposed on the structure, and the tool is movable with respect to the frame, so that, at each of a plurality of positions, the second end of the tool is capable of engagement with a respective bolt disposed in an internal support structure of a nuclear reactor vessel.
056205368	abstract	A method of manufacturing nuclear fuel elements which include fuel rods whose cladding tubes are provided with an internal liner layer to obtain PCT resistance in the nuclear fuel element involves carefully choosing parameters for heat treatment of the inner component even from the machining of an ingot of the inner component. The internal layer of zirconium or a zirconium alloy, suitable as inner layer in a PCI-resistant cladding, from the fabrication of an ingot of the inner component up to the completion of a cladding tube, including forging, rolling, extrusion, heat treatment and final heat treatment, is manufactured in such a way that the temperature in the inner component never exceeds the temperature when an incipient phase transformation to beta phase takes place.
	claims	1. A nuclear power plant comprising:a nuclear reactor;a steam system including a high pressure turbine and a lower pressure turbine, which are supplied with steam generated in said nuclear reactor;a condenser for condensing the steam discharged from said low pressure turbine;a plurality of feedwater heaters for heating feedwater supplied from said condenser;at least one extraction line for extracting the steam from said steam system and introducing the extracted steam to corresponding one of said feedwater heaters;a feedwater system for introducing the feedwater from said condenser to said nuclear reactor via said feedwater heaters;an extracted flow control valve and an extraction flow rate measuring meter disposed in said at least one extraction line; andan extracted flow controller for outputting an opening request command for said extracted flow control valve based on a measured value from said extraction flow rate measuring meter and a set value of a flow rate of the extracted steam,said nuclear power plant being operated such that second nuclear thermal power in a second operation cycle of said nuclear reactor is uprated from first nuclear thermal power in a first operation cycle before the second operation cycle, andsecond feedwater temperature in the second operation cycle is made lower than first feedwater temperature in the first operation cycle.
044951442	abstract	A fission chamber detector system for monitoring neutron flux density in a nuclear reactor utilizes a unique coaxial cable carried through a flexible metal hose to provide sufficient signal quality to allow a preamplifier and signal conditioning unit for amplifying and conditioning neutron signal pulses produced by the fission chambers to be far enough away from the fission chambers as to be located outside of the containment vessel for the reactor. Reactor power and rate-of-reactor-power-change signals produced for overlapping power ranges from a countrate circuit and a mean square voltage circuit are aligned by a voltage controlled switch and a slave switch without causing spurious transients in the rate-of-change signals. Power signal indications are provided over 12 decades. The preamplifiers include an input stage that enables the preamplifiers to be controlled remotely to either pass or inhibit neutron signal pulses to an amplifier stage from the fission chambers, and to pass test signals to the amplifier stage.
	description	The present application claims the benefit of U.S. Provisional Application Ser. No. 61/286,905, filed Dec. 16, 2009, the entirety of which is hereby incorporated by reference. The present invention relates generally to the field of transferring high level radioactive materials, and specifically to a canister apparatus and method for transferring high level radioactive materials in a submerged state. 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. Removal from the storage pool and transport of the loaded canister to the storage cask is facilitated by a transfer cask. In facilities utilizing transfer casks to transport loaded canisters, an empty canister is placed into the cavity of an open transfer cask. The canister and transfer cask are then submerged in the storage pool. As each assembly of spent nuclear fuel is depleted, it is removed from the reactor and lowered into the storage pool and placed in the submerged canister (which is within the transfer cask). The loaded canister is then fitted with its lid, enclosing the spent nuclear fuel and water from the pool within. The canister and transfer cask are then removed from the pool by a crane and set down in a staging area to prepare the spent nuclear fuel for storage in the “dry state.” Once in the staging area, the water contained in the canister is pumped out of the canister. This is called dewatering. Once dewatered, the spent nuclear fuel is dried using a suitable process such as vacuum drying. Once dry, the canister is back-filled with an inert gas such as helium. The canister is then sealed and the canister and the transfer cask are once again lifted by the plant's crane and transported to an open storage cask. The transfer cask is then placed atop the storage cask and the canister is lowered into the storage cask. Because a transfer cask must be lifted and handled by a plant's crane (or other equipment), transfer casks are designed to be a smaller and lighter than storage casks. 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. Additionally, a transfer cask must still perform the important function of providing adequate radiation shielding for both the neutron and gamma radiation emitted by the enclosed spent nuclear fuel. As such, transfer casks are made of a gamma absorbing material such as lead and contain a neutron absorbing material. However, the allowable weight of a transfer cask is limited by the lifting capacity of the plant's crane (or other lifting equipment). The load handled by the crane includes not only the weight of the transfer cask itself, but also the weight of the transfer cask's payload (i.e., the canister and its contents). A transfer cask must be designed so that the total load handled by the crane during all handling evolutions does not exceed the crane's rated weight limit, which is typically in the range of 100-125 tons. Because the weight of the transfer cask's payload varies during the different stages of the transport procedure, the permissible weight of the transfer cask is equal to the rated capacity of the plant crane less the weight of the transfer cask's maximum payload at any lifting step. The weight of the transfer cask's payload is at a maximum when the transfer cask and canister are lifted out of the storage pool, at which time the canister is full of spent nuclear fuel and water. Thus, according to prior art methods, it is at this stage that the permissible weight of a transfer cask is calculated. The transfer cask is then constructed using this permissible weight as a design limitation. Additionally, many nuclear sites have more than one reactor unit and more than one storage pool. Each of the storage pools might have its own crane, and the rated capacity of one crane at one storage pool might be different from the rated capacity of the crane at other storage pools. In nuclear sites with multiple pools and multiple cranes with different rating capacities, it might be desirable to move the depleted fuel assemblies from one pool, with a crane having a lower rating capacity, to another pool having a crane with a higher rating capacity, prior to placing the depleted fuel assemblies into a canister, such as a multi-purpose canister (“MPC”) within a transfer cask. This is because the rated capacity of a crane at one pool might not be able to safely lift a fully loaded transfer cask (with depleted fuel assemblies and canister). Therefore, there is a need for a system and method of transferring the depleted fuel assemblies from one pool, having a crane that cannot safely lift a fully loaded transfer cask, to another pool, having a crane with a rating capacity that can safely lift a fully loaded transfer cask. Since the pools in some of these sites are not interconnected to permit underwater transfer of the depleted fuel assemblies from one pool to another, a transfer canister for inter-unit transfer of depleted fuel assemblies is needed. It is desirable that depleted fuel assembly transfer from one pool to another be accomplished in the minimum amount of time (and hence radiation dose), with multiple assemblies at one time, with minimized upending and downending operations that carry the risk of handling accidents, with minimized (or eliminated) reliance on forced cooling methods that may introduce operation vulnerability to the transfer process, ensuring no risk of a criticality event, and with maximized protection against events such as crane malfunctions. Thus, a need exists for a method and apparatus for transferring high level radioactive materials from a first submerged environment to a second submerged environment that accomplishes the aforementioned goals. The present invention is directed to a method and apparatus for transferring high level radioactive materials from a first pool to a second pool that uses the pool water to minimize the thermal shock to the high level radioactive waste payload, to provide neutron radiation shielding, and to extract the decay heat from the high level radioactive waste payload to keep them cool. In one embodiment, the high level radioactive waste payload is depleted fuel assemblies. The present invention is also directed to a shielded transfer canister for inter-unit transfer of spent nuclear fuel assemblies with additional pressure relief volume that is isolated from canister's fuel storage cavity through one or more pressure relief devices, and a method incorporating the canister. In one embodiment, the invention can be a method of transferring high level radioactive waste comprising: a) loading high level radioactive waste into a water-filled cavity of a canister body having an open top end at a first location; b) coupling a lid to the canister body to enclose the open top end; c) removing a volume of water from the cavity so that a water level of the water within the cavity is above a top end of the high level radioactive waste and a space exists between the water level and a bottom surface of the lid; d) hermetically sealing the cavity; and e) transferring the canister to a second location, the water level remaining above the top end of the high level radioactive waste during the transfer. In an alternate embodiment, the invention can be a method of transferring spent nuclear fuel from a first body of water to a second body of water comprising: a) submerging a canister into the first body of water, the canister having a cavity having an open top end and a closed bottom end, the water filling the cavity; b) loading spent nuclear fuel into the cavity of the submerged canister; c) positioning a lid atop the loaded canister to enclose the open top end of the cavity; d) removing the loaded canister from the first body of water, the spent nuclear fuel remaining submerged in the water within the cavity; e) hermetically sealing the cavity; f) transferring and submerging the loaded canister to the second body of water; g) removing the lid from the loaded canister; and h) removing the spent nuclear fuel from the submerged canister. In another alternate embodiment, the invention can be a canister apparatus for transferring spent nuclear fuel comprising: a tubular body forming a cavity for receiving spent nuclear fuel, the tubular body having a longitudinal axis, a floor enclosing a bottom end of the tubular body, an open top end; and a lid detachably coupled to the tubular body that encloses the open top end of the tubular body and hermetically seals the cavity, the lid comprising a chamber and a pressure relief device hermetically sealing an opening into the chamber, the pressure relief device automatically opening upon the pressure within the cavity exceeding a predetermined threshold so as to form a passageway from the cavity into the chamber. These and various other advantages and features of novelty that characterize the invention are pointed out with particularity below. For a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention. Referring to FIGS. 1 and 2 concurrently, the exterior of a shielded canister 100 is illustrated according to one embodiment of the present invention. The shielded canister 100 is a pressure vessel designed for use in a substantially vertical orientation, as depicted in FIG. 1. The shielded canister 100 is preferably a substantially cylindrical containment unit with a longitudinal axis A-A having a horizontal cross-sectional profile that is substantially circular in shape. It should be noted, however, that the invention is not limited to cylinders having circular horizontal cross sections but may also include containers having cross-sectional profiles that are, for example, rectangular, ovoid or other polygon forms. While the shielded canister 100 is particularly useful for use in conjunction with transporting spent nuclear fuel (SNF) assemblies, the invention is in no way limited by the type of high level radioactive materials to be transported in certain embodiments, unless specifically recited in the claims. The shielded canister 100 can be used to transport almost any type of high level radioactive materials (HLW). However, the shielded canister 100 is particularly suited for the transport and/or cooling of high level radioactive materials that have a residual heat load and produce neutron and gamma radiation, such as SNF. As discussed in more detail below, the shielded canister 100 generally comprises a tubular body 60 and a removable lid 20. The tubular body 60 comprises a body portion 13, an upper structural ring 11, and a floor/base plate 12. The tubular body 60 is preferably tubular in shape and forms an internal storage cavity 31 for storing spent nuclear fuel assemblies. When fully assembled, the tubular body 60 forms a hermetically sealed fluid containment boundary about the storage cavity 31. In the exemplified embodiment, the body portion 13 of the tubular body 60 comprises three concentrically arranged tubular shells, namely an inner shell 14, an intermediate shell 15, and an outer shell 16. The body portion 13 of the tubular body 60 provides a desired level of gamma radiation shielding. If desired, the body portion 13 could further include layers to provide a level of neutron radiation shielding. Thus, the tubular body 60 may provide both gamma and neutron radiation shielding properties while at the same time facilitating improved cooling of the HLW stored inside the cavity by efficiently conducting heat away from the HLW. In an alternate embodiment, the body portion 13 of the tubular body 60 is formed with two concentrically arranged and spaced apart shells that comprise an annular gap in-between. The annular gap is then filled with a gamma radiation absorbing material such as lead. It is desired that the body portion 13 of the tubular body 60 be constructed so as to be efficient conductive path for thermal energy. As noted above, the shielded canister 100 comprises the tubular body 60 and a removable lid 20. The tubular body 60 comprising a body portion 13, an upper structural ring 11, and a floor/base plate 12. Further, the tubular body 60 is preferably tubular in shape and forms an internal storage cavity 31 for storing spent nuclear fuel assemblies. The floor/base plate 12 is hermetically sealed to a bottom end 99 of the body portion 13 of the tubular body 60. The floor/base plate 12 fully encloses and seals the bottom of the tubular body 60. Preferably, the floor/base plate 12 is welded to the bottom of the body portion 13 of the tubular body 60, thereby hermetically sealing the bottom end of the cavity 31. The floor/base plate 12 functions as the floor of the cavity 31 of the shielded canister 100 and preferably has a flat bottom for stability. The upper structural ring 11 is connected to the top of the body portion 13 of the tubular body 60 and forms an open top end 98 of the tubular body 60. The upper structural ring 11 comprises an opening and is concentric with the body portion 13 of the tubular body 60, thereby forming a passageway into an open top end of the cavity 31. Preferably, the upper structural ring 11 is welded to the top edge of the body portion 13 of the tubular body 60. It is also preferred that the opening in the upper structural ring 11 be the same diameter as the internal storage cavity 31 of the shielded canister 100. In the preferred embodiment the floor/base plate 12 and top structural ring 11 are hermetically sealed to the inner and outer shells 14, 16 of the body portion 13 of the tubular body 60. As discussed in more detail below, the removable lid 20 is configured so that it may be detachably coupled to the top end 98 of the tubular body 60 in a manner that hermetically seals the open top end 98 of the tubular body 60. One or more annular gaskets may be used at the interface between the lid 20 and the tubular body 60. In the exemplified embodiment, the removable lid 20 is sealed to the structural ring 11 using bolts 50. The removable lid 20 is designed to rest atop and be removable/detachable from the top structural ring 11 of the tubular body 60. When the removable lid 20 is bolted to the top structural ring 11 of the tubular body 60, the removable lid forms a hermetic seal with the tubular body 60 of the shielded canister 100. In the preferred embodiment, both the floor/base plate 12 and the structural ring 11 are thick steel forgings. The tubular body 60 forms an internal storage cavity 31 for receiving and storing the SNF assemblies, which can still give off considerable amounts of heat. The cavity 31 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 31 is generally circular in shape, but is dependent on the shape of the inner shell 14 of the tubular body 60, which is not limited to circular. The top end of the cavity 31 is open, providing access to the cavity 31 from outside of the shielded canister 100 (the removable lid 20 provides closure to the top end of the cavity 31 when secured to the shielded canister 100). The bottom end of the cavity 31 is closed by the floor/base plate 12. More specifically, the top surface of the floor/base plate 12 acts as a floor for the cavity 31. The shielded canister 100 forms a containment boundary about the storage cavity 31 (and thus the stored SNF assemblies). The containment boundary can be literalized in many ways, including without limitation a gas-tight containment boundary, a pressure vessel, a hermetic containment boundary, a radiological containment boundary, and a containment boundary for fluidic and particulate matter. These terms are used synonymously throughout this application. In one instance, these terms generally refer to a type of boundary that surrounds a space and prohibits all fluidic and particulate matter from escaping from and/or entering into the space when subjected to the required operating conditions, such as pressures, temperatures, etc. Referring to FIG. 2, the internal components making up the body portion 13 of the tubular body 60 of the shielded canister 100 according to one embodiment of the present invention are illustrated. As noted above, in the exemplified embodiment, the body portion 13 of the tubular body 60 comprises the inner shell 14, the intermediate shell 15 and the outer shell 16. In the preferred embodiment, the tubular body 60 is made as thick as possible within the constraints of the lifting equipment's capacity. The maximized weight enhances shielding protection and imparts a greater thermal inertia to the shielded canister 100, making the temperature rise more gradual as the shielded canister 100 is lifted out of a pool and carried in open air. The inner shell 14 comprises an inner surface 97 and an outer surface 96, and is the innermost shell of the body portion of the tubular body 60. As a result, the inner surface 97 of the inner shell 14 forms the walls of the cavity 31 in which the spent nuclear fuel assemblies are placed and held for storage and/or transport. The inner shell 14 forms the initial boundary separating the spent nuclear fuel from the external environment. Accordingly, the inner shell 14 is preferably made of a high strength steel such as, for example, SA 203 E and is preferably sufficiently thick to account for the known degradations in molecular structure from long-term exposure to neutron and gamma rays. Steel is also a preferred material to use for the inner shell 14 due to its good thermal conductivity, which is important for providing a path for the decay heat generated by the contained radioactive material to pass through (and ultimately be dissipated into the environment). Finally, steel is also preferred due to its high melting point, which ensures that the integrity of the inner shell 14 is not compromised even at high temperatures. The intermediate shell 15 comprises an inner surface 95 and an outer surface 94, and is concentrically arranged to circumferentially surround an outer surface 96 of the inner shell 14. In the preferred embodiment, the inner surface 95 of the intermediate shell 15 is concentric to and in contact with the outer surface 96 of the inner shell 14. Therefore, the intermediate shell 15 is both concentric to and coaxial with the inner shell 14. In the preferred embodiment, the intermediate shell 15 is formed of lead, however in alternate embodiments the intermediate shell 15 may be formed of steel or another good conductor of heat that also acts a gamma radiation absorber. The outer shell 16 comprises an inner surface 93 and an outer surface 92, and circumferentially surrounds an outer surface 94 of the intermediate shell 15. The outer shell 16 is both concentric to and coaxial with the inner shell 14 and the intermediate shell 15. The outer surface 92 of the outer shell 16 comprises the outer surface of the tubular body 60 of the shielded canister 100. In the exemplified embodiment, the outer shell 16 is formed of steel, however in alternate embodiments the outer shell 16 may be formed of lead, another metal or a metal alloy. In the exemplified embodiment, the outside surface 92 of the outer shell 16 of the tubular body 60 comprises extended surfaces 19 that extend radially from the tubular body 60 to enhance the heat dissipation to the shielded canister 100. Preferably, the extended surfaces 19 are fins or dimples. The extended surfaces 19 minimize the heat-up rate of water within the shielded canister 100 through the use of convection. The term “concentric” as used herein is not limited to an arrangement wherein the shells 14, 15, 16 are coaxial, but includes arrangements wherein the shells 14, 15, 16 may be offset. Furthermore, the term “annular,” as used herein, is not limited to a circular shape and does not require that the object or space have a constant width. For example, the inner shell 14 may have a circular transverse cross-section while the intermediate shell 15 may have a rectangular transverse cross-section. Any of the shells may be formed by bending a rectangular plate into a cylinder or other shape and welding together the two meeting ends, welding a series of elongated rectangular plates together end-to-end, or by any other method known to those skilled in the art to produce the desired shape. A machining process may also be used. Referring still to FIG. 2, a longitudinal cross-sectional view of the shielded canister 100 in partial cut-away along line A-A of FIG. 1 is illustrated according to one embodiment of the present invention. From this perspective, the outer shell 16, the intermediate shell 15 and the inner shell 14 are seen oriented along axis A-A and extending from the floor/base plate 12 to the upper structural ring 11 of the shielded canister 100. It is preferred that the upper structural ring 11 and the floor/base plate 12 are made of carbon steel and are each welded to the respective ends of the inner shell 14 and outer shell 16. As discussed in more detail below, once the cavity 31 of the inner shell 14 is loaded from the top, the removable lid 20 may be installed over to seal the opening of the structural ring 11. In the preferred embodiment, inside the cavity 31 is an upright fuel basket 30 with multiple fuel storage cavities 36 for receiving spent nuclear fuel assemblies (not shown). An example of a basket assembly is disclosed in U.S. Pat. No. 5,898,747 (Singh), issued Apr. 27, 1999, the entirety of which is hereby incorporated by reference. The invention, however, is not limited to the use of any specific canister structure. The basket 30 is formed from a honeycomb gridwork 32 of plates 33a-33c and 34a-34c having neutron absorber material 35 positioned in areas which form walls of storage cells formed by the honeycomb structure. The honeycomb structure of fuel basket 30 results in vertical cells 36 (also called “fuel cavities” or “storage cells”), each one of which is designed to hold one spent nuclear fuel assembly. The storage cells 36 are preferably created by arranging a gridwork of plates in a rectilinear arrangement. The basket 30 is formed from an array of plates 33a-33c and 34a-34c welded to each other, such as to form a honeycomb structure. Of course, slotted connection can be sued. In the exemplified embodiment, the height of the fuel basket 30 is less than the height of the cavity 31 of the shielded canister 100 so as to allow room for a top plenum of water and/or vapor as discussed below. In alternate embodiments, the number of plates or storage cells may differ, and/or the basket 30 may employ sleeves or boxes within the storage cells. The fuel basket 30 is configured to facilitate a natural thermosiphon flow of fluid within the hermetically sealed cavity 31 when the spent nuclear fuel assemblies are loaded within the cavity 31 and giving off a heat load. When SNF is loaded into storage cells 36 of the shielded canister 100, the heat emanating from the SNF conducts into the fluid of the cavity 31 that is contact with the SNF. The warmed fluid (which as discussed below is preferably pool water) rises within the cells 36 and into a top plenum of fluid. As the heated fluid comes into contact with the walls of the cavity 31, the heat is conducted radially outward through the tubular body 60 and the lid 20. As a result of this cooling, the fluid adjacent the walls flows downward through downcomer passageways (which can be empty fuel cells). This downardly flowing cooled fluid flows to the bottom of the cavity 31. A plurality of openings 185 are provided at the bottom end of the basket 30. The openings 185 form passageways between the all of the cells 36 and the downcomer passageways, thereby creating a bottom plenum. Once the cooled fluid flows into the bottom plenum, it is redistributed back in the cells 36 loaded with the SNF where it is heated and rises, thereby completing a thermosiphon cycle. In one embodiment, the top plenum may be formed by that volume of fluid located above a top edge of the basket 30 and below a fluid level. The existence of the top plenum allows for radially outward fluid flow. The bottom plenum allows radially inward fluid flow. Referring now to FIG. 3, an embodiment of the removable lid 20 of the shielded canister 100 of the present invention is illustrated. In the preferred embodiment, the removable lid 20 is a non-unitary structure relative to the tubular body 60. The lid 20, in the exemplified embodiment, is detachably coupled by bolts 50 to the upper structural ring 11 of the tubular body 60. The removable lid 20 rests atop and is supported by the upper structural ring 11, which rests atop and is secured to the top edges of the inner, intermediate, and outer shells 14, 15, 16 of the tubular body 60. The removable lid 20 encloses the top of the cavity 31 and provides the necessary radiation shielding so that radiation can not escape from the top of the cavity 31 when the canister is loaded with HLW stored therein. The removable lid 20 is specially designed to hermetically seal the open top end of the shielded canister 100 when properly installed. In one embodiment, the lid 20 is formed as a multi-layered construct of lead and steel. It should be noted that in alternate embodiments, the removable lid 20 may be detachably coupled to the shielded canister 100 through other means. The components of the removable lid 20 according to one embodiment of the present invention will be discussed. In the exemplified embodiment, the removable lid 20 comprises a body portion 21 and a dome portion 24. The body portion 21 of the removable lid 20 comprises a flange portion 22 and a plug portion 23. Further, the body portion 21 has a top surface 91 and a bottom surface 90. When the removable lid 20 is positioned atop the tubular body 60, the bottom surface 90 of the body portion 21 of the lid 20 forms a roof of the cavity 31. The plug portion 22 extends downward from the bottom of the flange portion 22. The flange portion 22 surrounds the plug portion 23, extending therefrom in a radial direction. The dome portion 24 is attached to the top surface 91 of the body portion 21. The dome portion 24 extends upward from the top surface 91 of the body portion 21 in the shape of a dome and forms an internal chamber 25 therein. In alternate embodiments, the dome portion 24 can be any shape or size that is desired. In one embodiment, the body portion 21 of the removable lid 20 can be formed of both neutron and/or gamma radiation absorbing materials, including neutron absorbing plates such as lead. The cooperational relationship of the elements of the removable lid 20 and the elements of the tubular body 60 will now be described. When the removable lid 20 is properly positioned atop the tubular body 60 of the shielded canister 100, the plug portion 23 of the removable lid 20 extends into the cavity 31 until the flange portion 22 of the removable lid 20 contacts and rests atop the upper structural ring 11. The flange portion 22 eliminates the danger of the removable lid 20 falling into the cavity 31. When the removable lid 20 is positioned atop the upper structural ring 11, one or more gasket seals 18 are compressed between the flange portion 22 of the removable lid 20 and the top end 98 of the tubular body 60, thereby forming a hermetically sealed interface. The gasket seal 18 provides a positive seal at the lid/body interface, hermetically sealing the shielded canister 100. Once the removable lid 20 is positioned atop the upper structural ring 11 of the shielded canister 100, the removable lid 20 is secured to the upper structural ring 11 with bolts 50. In alternate embodiments, the removable lid 20 may be secured to the upper structural ring 11 through other connecting means. The dome portion 24 comprises an inner surface 26, an outer surface 27, and a resulting dome chamber 25. The bottom portion of the outer surface 27 of the dome portion 24 is secured to the top surface 91 of the body portion 21 of the removable lid 20. The dome chamber 25 is formed by a cavity created by the inner surface 26 of the dome portion 24. As discussed in more detail below, the dome chamber 25 may be formed having a vacuum pressure therein to provide additional volume to relieve excess pressure that may accumulate in the cavity 31 of the shielded canister 100 when the removable lid 20 is hermetically sealed atop the shielded canister 100. The removable lid 20 further comprises a first passageway 70 that extends from the dome chamber 25 through the flange portion 22 and plug portion 23, and into the cavity 31 of the shielded canister 100. The first passageway 70 extends from an opening 71 in the bottom of the dome chamber 25 to an opening 72 in the bottom surface 90 of the body portion 21 of the lid 20, thereby forming a passageway from the cavity 31 to the chamber 25. A pressure relief device 73 is operably coupled to the opening 72 in the bottom surface 90 of the body portion 21 of the removable lid 20 and hermetically seals the first passageway 70. The pressure relief device 73 extends from at least part way in the first passageway 70 into the cavity 31 of the shielded canister 100 in the exemplified embodiment. In the preferred embodiment, the pressure relief device 73 is made of a ductile and thermally conductive material, such as steel or lead, or a combination thereof. As discussed in more detail below, the pressure relief device 73 is configure to open the first passageway 70 when the pressure inside the cavity 31 exceeds a threshold value, and thereby reduce the pressure inside the cavity 31 of the shielded canister 100 by opening the first passageway 70 between the cavity 31 and the dome chamber 25 of the removable lid 20. The pressure relief device 73 may be a pressure relief valve, a rupture disk, or other devices as are know in the art. In alternate embodiments, the first passageway 70 may be a tortuous passageway so no direct line of sight exists between the cavity 31 of the shielded canister 100 and the chamber of the dome portion 23 of the removable lid 20. The removable lid 20 further comprises a valve port 75 for adjusting the water level within the cavity 31 of the shielded canister 100. The valve port 75 comprises a port that extends through a second passageway (not shown) and is operably coupled to a valve on the outside of the shielded canister 100. In the preferred embodiment, a second passageway extends from a second opening (not shown) in the bottom of the plug portion 23 of the removable lid 20 to an opening (not shown) in the top surface 91 of the body portion 21 of the removable lid 20. The valve port 75 preferably extends from inside the cavity 31 of the shielded canister 100, through the second passageway, and out of the opening in the top surface 91 of the body portion 21. Preferably, the valve port can be adjusted between a closed position where the cavity 31 remains hermetically sealed, and an open position where the hermetic seal is alleviated so that the valve port can be sued to introduce or expel a fluid into or out of the cavity 31. In the preferred embodiment, the valve port 75 extends into the cavity 31 to a point above the top of the basket assembly 30 located within the cavity 31. Thus, the valve port is capable of reducing the water level within the cavity 31 of the shielded canister 100 to a level slightly above the top of the basket assembly by pumping out the excess water. Keeping the water level above the basket assembly 30 allows for proper thermosiphon flow of the water to aid in cooling the spent nuclear fuel assemblies residing within the basket assembly 30. Further, in alternate embodiments, the valve port, 75 is configured to backfill the cavity 31 of the shielded canister 100 with a gas, preferably steam, to alter the internal pressure of the shielded canister 100 and to maintain a space as the volume of liquid water may expand due to the thermal heating. Next, the preferred method of the present invention will be described in detail. Many nuclear plant sites have more than one reactor unit and more than one fuel pool. At such plants, it may be necessary to have the means to transfer the spent nuclear fuel assemblies from one pool to another by moving them out of the fuel building of one unit and into another through the recipient building's truck bay. One method of carrying out such a transfer in accordance with the present invention will be described below. At an initial step, the tubular body 60 (with the lid 20 removed) is lifted with a first crane in the first building and is lowered and submerged in a first storage body of water (pool) at a nuclear site. Specifically, the first storage pool may have a crane with a limited rated lilting capacity, and particularly with a lifting capacity that is not rated for the removal of a fully loaded transfer cask from a submerged state within the first pool. Once the tubular body 60 is submerged in the first pool, the pool water automatically fills the cavity 31. Spent nuclear fuel assemblies are then loaded into the basket 30 of the tubular body 60 while the tubular body 60 and spent nuclear fuel assemblies remain submerged in the first fuel pool. Specifically, the spent nuclear fuel assemblies are loaded into the cells 36 of the cavity 31 via the open top end 98 of the tubular body 60. Thereafter, the removable lid 20 is coupled atop the tubular body 60 to enclose the open top end 98 while the shielded canister 100 remains submerged underwater in the pool. Next, the first crane lifts the shielded canister 100 from the pool and into a staging area. Once at the staging area, the removable lid 20 is secured to the tubular body 60, thereby forming a pressure vessel in which the spent nuclear fuel assemblies and the water are contained assuming the valve port 75 is in the closed position). In alternate embodiments, an intermediate lid may be placed atop the shielded canister 100 prior to removing it from the pool. In such embodiments, once outside of the pool and in the staging area, the intermediate lid is removed and the removable lid 20 is hermetically sealed to the shielded canister 100. After the shielded canister 100, with removable lid 20 hermetically attached, is removed from the pool, the shielded canister 100 is transferred to a second pool. In one embodiment, once removed from the first pool, a portion of the water from the cavity 31 of the shielded canister 100 is removed using the valve port 75 so that the water level within the cavity 31 is above the top of the fuel basket 30 (and HLW) and a space exists between the water level and the bottom surface 90 of the lid. Controlling the water level so that it is above the top of the baskets ensures proper thermosiphon flow to aid in cooling the spent nuclear fuel assemblies while they are inside the hermitically sealed shielded canister 100. It should be noted that the removal of the water from the cavity 31 may be done before or after the removable lid 20 is hermetically sealed atop the shielded canister 100. After the water level within the cavity 31 is adjusted to be at the desired level, the valve of the valve port 75 is closed, thereby hermetically sealing the shielded canister 100. In one embodiment, the space formed above the water level and the bottom surface of the lid 20 may be backfilled with a gas via the valve port 75, preferably steam, to alter the internal pressure of the shielded canister 100. After backfilling the cavity with a gas, the valve of the valve port 75 is closed and the cavity 31 is hermetically sealed. During transfer from the first pool to the second pool, the shielded canister 100, and specifically the removable lid 20 provide for the safe transfer of the spent nuclear fuel assemblies. Preferably, the water level remains above the top of the fuel baskets 30 during transfer to the second pool. Due to the limited lifting capacity of the first crane, a transfer cask (weighing in the upwards of 100-125 tons) could not be used. To counteract the reduced material and weight of the shielded canister 100, and yet still provide sufficient neutron and gamma radiation protection, the shielded canister 100 contains water within cavity 31 during the transfer from the first pool to the second pool. In order to ensure that the water within the cavity 31 does not reach a boiling point, the shielded canister 100 is hermetically sealed with the removable lid 20 that comprises the pressure relief device 73. The removable lid 20, the pressure relief device 73 and the dome chamber 25 aid in preventing the water within cavity 31 from reaching a boiling point. To do so, the pressure relief device 73 is configured to automatically open the passageway 70 between the cavity 31 and the dome chamber 25 upon the equilibrium pressure within the cavity 31 reaching a threshold potential. If the equilibrium pressure within the cavity 31 does reach and/or exceed the threshold potential, the pressure relief device 73 automatically opens the passageway 70 thereby increasing the overall volume and reducing the resulting pressure, while maintaining the hermetic seal within the shielded canister 100. Upon arriving at the second pool, the shielded canister 100 is lowered into the pool through the use of a second crane. Preferably, the second crane has a rated lifting capacity that exceeds the weight of a fully loaded transfer cask. Once in the second pool, the spent nuclear fuel assemblies located within the basket of the shielded canister 100 are removed and preferably placed into a second canister that is located within a transfer cask. Thereafter, the shielded canister 100 is removed from the pool. 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.
	summary
046648755	claims	1. In combination with a reconstitutable fuel assembly being held in a fixed position within a work station wherein said fuel assembly includes a top nozzle with an adapter plate having at least one passageway, at least one guide thimble with an upper end portion and an attaching structure releasably mating said upper end portion of said guide thimble within the passageway of said top nozzle adapter plate, said guide thimble being held in said fixed position, a fixture for removing and replacing said top nozzle from and to said guide thimble, comprising: (a) a base; (b) means for movably mounting said base on said work station in alignment with said top nozzle of said fuel assembly; (c) means for locking said top nozzle to said base when said base is movably mounted on said work station; (d) means for moving said base, and said top nozzle therewith when locked thereto, relative to said work station so as to lift said top nozzle away from said guide thimble and thereby cause release of said attaching structure and removal of said top nozzle from said guide thimble and so as to lower said top nozzle toward said guide thimble and thereby cause mating of said attaching structure and replacement of said top nozzle back on said guide thimble, said moving means including (e) means for gripping said reaction pins and anchoring them in stationary relation to said work station such that rotation of said drive means in a second, opposite sense results in replacement of said top nozzle back onto said fuel assembly by causing relative movement of said base and reaction pins in opposite directions respectively toward and away from said work station and thereby said base, and said top nozzle therewith when locked thereon, toward said guide thimble when said reaction pins are anchored in said stationary relation to said work station. (e) means aligning said base with said guide thimble when said base is movably mounted on said work station. (e) means operable for establishing a reference representing the displacement between said base and said work station when said top nozzle is locked to said base but before said base and top nozzle have been lifted away from said work station for facilitating replacement of said top nozzle back onto said guide thimble at the same axial position on said fuel assembly as it was prior to removal. at least one elongated member movably mounted on said base and extending toward said work station when said base is movably mounted on said work station, said member being biased for movement away from said base; and means on said base engagable with said elongated member and operable for securing it in a fixed position relative to said base. said reaction pins are threadably coupled to said base such that upon rotation said pins also move relative to said base along linear paths extending in generally transverse relation to said base; and said drive means includes a drive gear rotatably mounted on said base, and a plurality of driven gears corresponding in number to said plurality of reaction pins, said driven gears being rotatably mounted on said base and connected to said reaction pins, said driven gears also being intermeshed with said drive gear so as to be slidably movable in linear fashion relative to said drive gear concurrently as said driven gears are rotated by said drive gear for translating rotational movement of said drive gear into said movements of said reaction pins along said linear paths. releasable means mounted on one of said base and said top nozzle and matable with the other thereof for securing said top nozzle to said base. (a) a fixture base; (b) means on said base movably matable with said guide members of said work station for guiding said base into alignment with the top nozzle of the fuel assembly; (c) means on said base matable with said top nozzle of said fuel assembly and operable for locking said base thereto; (d) means on said base engagable with said top flange of said work station and operable for respectively lifting and lowering said base and said top nozzle locked thereto away from and toward said top flange so as to cause release of said attaching structures and unmating of said top nozzle adapter plate from said upper end portions of said guide thimbles and thereby removal of said top nozzle from said fuel assembly and so as to cause reengagement of said attaching structures and mating of said top nozzle adapter plate to said upper end portions of said guide thimbles and thereby replacement of said top nozzle back onto said fuel assembly; and (e) means on said base operable for establishing a reference representing the displacement between said base and said work station when said top nozzle is locked to said base but before said base and top nozzle have been lifted away from said top flange for facilitating replacement of said top nozzle back onto said guide thimbles at the same axial position on said fuel assembly as it was prior to removal, said reference establishing means including (e) means on said base aligning said base with at least some of said guide thimbles when said base is movably mounted on said work station. a plurality of elongated reaction pins extending from said base toward said top flange of said work station when said base is movably mounted on said work station; and drive means rotatably mounted on said base and coupled to said reaction pins such that rotation of said drive means in a first sense results in removal of said top nozzle from said fuel assembly by causing relative movement of said base and said reaction pins in opposite directions respectively away from and toward said top flange of said work station, and thereby movement of said base, and said top nozzle therewith when locked thereto, away from said guide thimbles after said reaction pins have made abutting engagement with said top flange. means on said top flange of said work station for gripping said reaction pins and anchoring them in stationary relation to said top flange such that rotation of said drive means in a second, opposite sense results in replacement of said top nozzle back onto said fuel assembly by causing relative movement of said base and reaction pins in opposite directions respectively toward and away from said top flange and thereby said base, and said top nozzle therewith when locked thereon, toward said guide thimbles when said reaction pins are anchored in said stationary relation to said top flange of said work station. said reaction pins are threadably coupled to said base such that upon rotation said pins also move relative to said base along linear paths extending in generally transverse relation to said base; and said drive means includes releasable means mounted on one of said base and said top nozzle and matable with the other thereof for securing said top nozzle to said base. (a) movably mounting a fixture on said work station in alignment with said top nozzle of said fuel assembly; (b) locking said top nozzle to a base of said fixture; (c) engaging a plurality of reaction pins movably mounted on said base with said work station; (d) moving said base, and said top nozzle therewith when locked thereto, relative to said reaction pins and away from said work station so as to lift said top nozzle off said guide thimble and thereby cause release of said attaching structure and removal of said top nozzle from said fuel assembly; (e) gripping and anchoring said reaction pins in a stationary relation with said work station; and (f) moving said base, and said top nozzle therewith being locked thereto, relative to said reaction pins and toward said work station so as to lower said top nozzle back onto said guide thimble and thereby cause reengagement of said attaching structure and replacement of said top nozzle back onto said fuel assembly. (e) establishing a reference representing the displacement between said base of said fixture and said work station when said top nozzle is locked to said base but before said base and top nozzle have been lifted away from said work station for facilitating replacement of said top nozzle back onto said guide thimble at the same axial position on said fuel assembly as it was prior to removal. 2. The fixture as recited in claim 1, further comprising: 3. The fixture as recited in claim 1, further comprising: 4. The fixture as recited in claim 3, wherein said reference establishing means includes: 5. The fixture as recited in claim 1, wherein: 6. The fixture as recited in claim 1, wherein said locking means includes: 7. The fixture as recited in claim 6, wherein said releasable means includes a pair of hollow expandable split sleeves fixedly mounted to said base and a pair of wedge pins mounted for axial movement in said respective sleeves, said sleeves being insertable within respective bores defined in said top nozzle such that when so inserted and said wedge pins are moved in a first direction said sleeves expand into frictional engagement with said bores and secure said top nozzle to said base, whereas when said wedge pins are moved in a second, opposite direction said sleeves contract and release the frictional engagement with said bores allowing removal of said base from said top nozzle. 8. In combination with a reconstitutable fuel assembly including a top nozzle with an adapter plate having a plurality of passageways, a plurality of guide thimbles with upper end portions and a plurality of attaching structures releasably mating said upper-end portions of said guide thimbles within said passageways of said top nozzle adapter plate, and also with a work station having a top flange, guide members mounted on said flange, and positioning means holding said fuel assembly in a fixed position relative to said work station, a fixture for removing and replacing said top nozzle from and to said guide thimbles, comprising: 9. The fixture as recited in claim 8, further comprising: 10. The fixture as recited in claim 8, wherein said engagable means includes: 11. The fixture as recited in claim 10, further comprising: 12. The fixture as recited in claim 10, wherein: 13. The fixture as recited in claim 8, wherein said locking means includes: 14. The fixture as recited in claim 13, wherein said releasable means includes a pair of hollow expandable split sleeves fixedly mounted to said base and a pair of wedge pins mounted for axial movement in said respective sleeves, said sleeves being insertable within respective bores defined in said top nozzle such that when so inserted and said wedge pins are moved in a first direction said sleeves expand into frictional engagement with said bores and secure said top nozzle to said base, whereas when said wedge pins are moved in a second, opposite direction said sleeves contract and release the frictional engagement with said bores allowing removal of said base from said top nozzle. 15. In combination with a reconstitutable fuel assembly being held in a fixed position within a work station wherein said fuel assembly includes a top nozzle with an adapter plate having at least one passageway, at least one guide thimble with an upper end portion and an attaching structure releasably mating said upper end portion of said guide thimble within said passageway of said top nozzle adapter plate, a method for removing and replacing said top nozzle from and to said guide thimble, comprising the steps of: 16. The method as recited in claim 15, further comprising the step of:
046882421	claims	1. An X-ray imaging system comprising: an X-ray source for emitting X-rays to be radiated on an object; X-ray image detection means for detecting an X-ray image emitted from said X-ray source and transmitted through said object; X-ray mask means, having a plurality of X-ray shielding regions distributed in a predetermined pattern, for locally shielding X-rays with said plurality of X-ray shielding regions; drive means for moving said X-ray mask means so that said X-ray mask means is inserted or removed with respect to an X-ray radiation field between said X-ray image detection means and said X-ray source and is sequentially positioned at a plurality of predetermined positions in said X-ray radiation field; storage means for storing X-ray image data; first calculating means, associated with said storage means, for calculating scattered X-ray intensity distribution data associated with said object based on a plurality of transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located at different positions in said X-ray radiation field, and on transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located outside said X-ray radiation field; second calculating means, associated with said storage means, for calculating X-ray image data, from which the influence of scattered X-rays is eliminated, in accordance with the scattered X-ray intensity distribution data obtained by said first calculating means and transmission X-ray data obtained by irradiating said object with X-rays when said X-ray mask means is located outside said X-ray radiation field; and image output means for outputting the X-ray image data calculated by said second calculating means as a visible image. 2. A system according to claim 1, wherein said X-ray mask means is an X-ray mask member comprising a plate of an X-ray transmitting material, on which a plurality of X-ray shielding segments are adhered. 3. A system according to claim 2, wherein said X-ray shielding segments are lead segments. 4. A system according to claim 1, wherein said drive means is means for automatically moving said X-ray mask means to be interlocked with said X-ray source and said X-ray image detection means. 5. A system according to claim 1, wherein said X-ray image detection means includes X-ray/photo conversion means for converting X-ray data into visible image data, and camera means for converting an output image from said X-ray/photo conversion means into an electrical signal. 6. A system according to claim 5, wherein said X-ray/photo conversion means is an image intensifier. 7. A system according to claim 1, wherein said first calculating means calculates said scattered X-ray intensity distribution data with the use of an interpolation calculation technique utilizing a SINC function. 8. A system according to claim 1, wherein said first calculating means has means for identifying whether or not present transmission X-ray intensity data masked by said X-ray mask means is said scattered x-ray intensity data, in accordance with whether or not the intensity data exceeds a predetermined threshold level. 9. A system according to claim 1, wherein said storage means is a means having a memory area for transmission X-ray data obtained when said X-ray mask means is located in said X-ray radiation field which memory area is smaller per one frame than a memory area for transmission X-ray data which is obtained when said X-ray mask means is located outside the X-ray radiation field.
	description	1. Field of the Invention The present invention relates to a plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly, capable of improving productivity in welding the guide thimbles and their end plugs constituting the nuclear fuel assembly. 2. Description of the Related Art Nuclear reactors are facilities for artificially controlling a fission chain reaction of a fissionable material in order to use thermal energy generated from nuclear fission as power. Nuclear fuel used in the nuclear reactor is manufactured by forming concentrated uranium into uniformly sized cylindrical pellets (hereinafter referred to as “sintered compacts”) and then charging a plurality of sintered compacts in a fuel rod. This plurality of fuel rods constitutes a nuclear fuel assembly, wherein the fuel rods are charged in a reactor core, and are then burnt by a nuclear reaction. The fuel rod assembly includes spacer grids 1 into which fuel rods are inserted, a plurality of guide thimbles (or guide tubes) 2 fixed to the spacer grids 1, an upper end fitting (or top nozzle) 3 fastened to upper ends of the guide thimbles 2, and a lower end fitting (or bottom nozzle) 4 fastened to lower ends of the guide thimbles 2. Each fuel rod is supported by dimples and springs formed on each spacer grid 1. Particularly, each guide thimble is coupled to the spacer grid and the upper and lower end fittings so as to form a framework of the nuclear fuel assembly, and supports a load of the fuel rods within the nuclear fuel assembly. Further, each guide thimble functions as a guide channel that guides insertion of a control rod controlling output of the nuclear reactor, as well as a passage channel for a poison rod or a neutron source rod. As a material of the guide thimble, a zirconium alloy is used like a cladding tube of the fuel rod. The guide thimble is configured so that an open lower end thereof is closed by a lower end plug. Thus, the control rod inserted into the guide thimble from the top is prevented from falling down by the lower end plug of the guide thimble. Since the guide thimble plays a considerably important role in the nuclear reactor, it should be manufactured with high precision. Particularly, a process of coupling the end plug requires very precise work in order to secure quality. Further, the process takes a very long time when it is manually carried out. Further, the guide thimble has a length of about four meters, and is difficult to handle. Furthermore, the guide thimble does not permit re-welding. When the guide thimble and its end plug are manually welded, this provides very low productivity, and there is a difficulty in securing a high quality. To automatize the process of welding the guide thimble and the end plug, the applicant of the present invention has proposed an automated welding apparatus and method for the guide thimble plug of the guide thimble in the nuclear fuel assembly, which is disclosed in Korean Patent Nos. 10-0775577 and 10-0775578 (issued on Nov. 5, 2007). These patents are designed to automatically supply the guide thimbles and their end plugs to a welding chamber so as to automatize welding work in the welding chamber. Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to provide a plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly, capable of increasing working efficiency and productivity using plasma welding rather than tungsten insert gas (TIG) welding. To achieve the aforementioned object, there is provided a plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly, which includes: a welding chamber including an end-plug inserting part into which the end plug is inserted and fixed, a guide-thimble inserting part which is provided on the same axis as the end-plug inserting part and into which the guide thimble is inserted and fixed, a torch assembling part to which a plasma welding torch is assembled so as to make a right angle with the end-plug inserting part and the guide-thimble inserting part, and argon inflow and outflow ports through which argon is supplied or discharged; an end-plug transfer unit supplying the end plug to the end-plug inserting part; and an guide-thimble transfer unit transferring the guide thimble to the guide-thimble inserting part. Here, the end-plug inserting part and the guide-thimble inserting part may be provided so as to be able to rotate relative to the welding chamber, and be rotated by a driving motor. Further, the end-plug inserting part and the guide-thimble inserting part may be assembled to the welding chamber via at least one bearing. Further, the argon inflow and outflow ports may be configured so that argon is introduced at a lower portion of the welding chamber and is discharged to an upper portion of the welding chamber. In addition, the guide-thimble inserting part may include a collet into which the guide thimble is inserted, a jig that horizontally moves along the collet in a forward/backward direction and provides the collet with a fastening force for fixing the guide thimble, and a lever operating the jig. In the plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly according to the present invention, the end plug and the guide thimble are transferred into the welding chamber by the end-plug transfer unit and the guide thimble transfer unit, and are welded in the welding chamber by the plasma welding torch, so that the plasma welding apparatus can increase productivity. Further, to prevent oxidization during welding, the interior of the welding chamber is maintained under argon atmosphere rather than under vacuum, and the welding is carried out. Thereby, an external appearance of the weld zone and soundness of a tensile test and a corrosion test can be satisfied without requiring separate vacuum equipment. Reference will now be made in greater detail to an exemplary embodiment of the present invention with reference to the accompanying drawings. Referring to FIGS. 2 and 3, a plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly according to an embodiment of the present invention includes a welding chamber 100 into which an end plug 10 and a guide thimble 20 are inserted and fixed and are subjected to plasma welding, an end-plug transfer unit 210 transferring the end plug 10 toward the welding chamber 100, and a guide-thimble transfer unit 220 that is located on an opposite side of the end-plug transfer unit 210 on the basis of the welding chamber 100 and transfers the guide thimble 20 toward the welding chamber 100. The welding chamber 100 and the end-plug transfer unit 210 are installed on a first stationary frame 101. The end-plug transfer unit 210 includes a bowl feeder 211 that stores, automatically aligns, and feeds a plurality of end plugs, an end-plug clamp 212 that loads the end plug fed from the bowl feeder 211 and inserts and fixes the end plug into and in the welding chamber 100, and an end-plug inserting driver that is connected with the end-plug clamp 212 by a shaft 213a and drives the end-plug clamp 212 in a forward/backward direction. In the present embodiment, the end-plug inserting driver may be made up of a pneumatic cylinder 215 that primarily drives the end-plug clamp 212 in a forward/backward direction, and a servo motor 214 that precisely positions the end-plug clamp 212. The guide-thimble transfer unit 220 is installed on a second stationary frame 201 just adjacent to the first stationary frame 101 in order to guide the long guide thimble in a horizontal direction, and is equipped with components that load/unload the guide thimble 20 toward/out of the welding chamber 100 above the second stationary frame 201. For example, the guide-thimble transfer unit 220 includes a loading rail 221 that loads the guide thimble 20 toward the welding chamber 100 above the second stationary frame 201, an unloading rail 222 that unloads the guide thimble 20 welded with the end plug for the following process, and a guide-thimble transfer driver 223 that loads/unloads the guide thimble 20 toward/out of the welding chamber 100 between the two rails 221 and 222. The guide-thimble transfer driver 223 is equipped with a guide-thimble clamp that grasps and fixes the guide thimble. The loading rail 221 and the unloading rail 222 are provided so as to have a smooth slope in a direction perpendicular to a transferring direction of the guide thimble. The guide thimble transferred to the loading rail 221 is loaded to the welding chamber 100 by the guide-thimble transfer driver 223, and is coupled with the end plug by plasma welding. The welded guide thimble is unloaded out of the welding chamber 100, is sent to the unloading rail 222 by the guide-thimble transfer driver 223, and is transferred to the next process along the unloading rail 222. The guide-thimble transfer driver 223 may be provided with a plurality of idle rollers 224 that support and guide the guide thimble in a transferring direction. FIG. 4 is an enlarged view showing only a welding chamber of the plasma welding apparatus for a guide thimble and guide thimble end plug of a nuclear fuel assembly according to the embodiment of the present invention. The welding chamber 100 includes an end-plug inserting part 110 into which the end plug is inserted and fixed, a guide-thimble inserting part 120 which is provided on the same axis as the end-plug inserting part 110 and into which the guide thimble 20 is inserted and fixed, a torch assembling part 130 to which a plasma welding torch 131 is assembled so as to make a right angle with the end-plug inserting part 110 and the guide-thimble inserting part 120, and argon inflow and outflow ports 141 and 142 through which argon is supplied or discharged. The welding chamber 100 has a chamber body 101 providing geometry. The chamber body 101 has the end-plug inserting part 110, the guide-thimble inserting part 120, the torch assembling part 130, and the argon inflow and outflow ports 141 and 142. The end-plug inserting part 110 is configured so that the end pug 10 is inserted and positioned in place by forward driving of the end-plug clamp 212, and fixes and supports the end plug 10 in the welding chamber 100 during welding. The guide-thimble inserting part 120 is provided on the same axis as the end-plug inserting part 110, and causes the guide thimble 20 to be inserted and positioned in place. In the present embodiment, the guide-thimble inserting part 120 includes a collet 122 into which the guide thimble 20 is inserted, a jig 123 that horizontally moves along the collet 122 in a forward/backward direction and provides the collet 122 with a fastening force for fixing the guide thimble 20, and a lever 124 operating the jig 123. The collet 122 has a plurality of slits S formed along one opening so as to provide elasticity, and is supported by a socket member 125. The jig 123 is installed on an outer circumferential surface of the collet 122, and provides the collet 122 with the fastening force for fixing the guide thimble 20 by moving relative to the collet 122 in a forward/backward direction. The lever 124 is assembled to the jig 123 for the forward/backward driving of the jig 123. Thus, when the lever 124 is manipulated, the jig 123 presses the collet 122 toward the socket member 125, so that the collet 122 clamps and fixes the guide thimble 20. In a state in which the end plug 10 fixed to the end-plug clamp 212 is supported by a pneumatic cylinder 215, the guide thimble 20 is fixed to the collet 122. The end plug 10 and the guide thimble 20 can be welded in a joined state. The torch assembling part 130 is located in a direction perpendicular to the end-plug inserting part 110 and the guide-thimble inserting part 120. The plasma welding torch 131 is inserted and fixed into the torch assembling part 130. A joint of the end plug and the guide thimble inserted and fixed into the end-plug inserting part 110 and the guide-thimble inserting part 120 is located at a welding position in front of the plasma welding torch 131. Meanwhile, the torch assembling part 130 may be additionally provided with a cylinder capable of moving the plasma welding torch 131 in an upward/downward direction. In a state in which the plasma welding torch 131 is assembled to the torch assembling part 130, the plasma welding torch 131 can be positioned in an upward/downward direction by operation of the cylinder. Further, an adjusting screw for precisely adjusting a position of the plasma welding torch 131 may be provided. In the present embodiment, as the plasma welding torch 131, a typical plasma welding torch using known plasma arc welding may be used. High-temperature plasma of 10,000 to 30,000° C. is ejected using high-temperature flame generated by ejecting arc plasma through a narrow gap at high speed. Thereby, the welding can be carried out. Plasma welding is similar to TIG welding in that arc is generated between a non-consumable tungsten rod and a base metal. However, in comparison with TIG welding, plasma welding has advantages in that the depth of fusion is deep, groove preparing work is reduced, and thermal deformation caused by welding heat input is reduced. Particularly, in plasma welding, since directivity and directionality of arc are excellent, control of the welding heat to the base metal is easy, allowing precise welding. Further, a length of arc is long. If a change in the length of a large arc is allowed, an amount of molten metal according to a change in the length of arc does not show a wide difference, so a uniform weld zone can be obtained. In comparison with TIG welding, plasma welding is barely influenced by a mismatch of the weld zone or poor fit-up, can obtain high welding speed due to transmission of high-density energy, and provides excellent directivity due to having a very steady arc and being barely influenced by a magnetic field. The argon inflow and outflow ports 141 and 142 are intended to maintain the interior of the welding chamber 100 under argon atmosphere while the end plug 10 and the guide thimble 20 are welded, and prevent oxidation of the weld zone which may be caused by exposure of the weld zone to oxygen during welding. In the present embodiment, the argon inflow and outflow ports 141 and 142 is configured so that the inflow port 141 is provided at a lower portion of the chamber body 101, and that the outflow port 142 is provided at an upper portion of the chamber body 101. Thus, argon is introduced from the lower portion of the chamber body 101 and is discharged to the upper portion of the chamber body 101. Above all, the end-plug inserting part 110 and the guide-thimble inserting part 120 are installed so as to be able to rotate relative to the welding chamber 100, and thus are rotated by a driving motor 310. In detail, referring to FIGS. 4 and 5, a plurality of bearings 102 are installed between the chamber body 101 and the end-plug inserting part 110 and between the chamber body 101 and the guide-thimble inserting part 120. The end-plug inserting part 110 and the guide-thimble inserting part 120 are allowed to rotate relative to the chamber body 101. Sprockets 111 and 121 are installed on outer circumferences of the end-plug inserting part 110 and/or the guide-thimble inserting part 120. The sprockets 111 and 121 may be connected with the driving motor 310 by a chain 311. Reference numeral 103 indicates a bearing case for supporting the chamber body 101 having the bearings 102, and is fixed to the first stationary frame by bolts. Thus, when the driving motor 310 is driven after the end plug 10 and the guide thimble 20 are fixed at a welding position, a driving force of the driving motor 310 rotates the end-plug inserting part 110 and the guide-thimble inserting part 120 via the chain 311, and the joint of the end plug and the guide thimble fixed to the end-plug inserting part 110 and the guide-thimble inserting part 120 is rotated relative to the plasma welding torch 131 at a constant speed, so that the plasma welding can be performed on the joint. A method of welding the guide thimble and the end plug using the plasma welding apparatus configured in this way is as follows. The end plug 10 fed from the bowl feeder 211 is loaded on the end-plug clamp 212, and then is inserted into the end-plug inserting part 110 of the welding chamber 100 by the end-plug inserting driver. Further, the guide thimble 20 is inserted into the guide-thimble inserting part 120 of the welding chamber 100 by the guide-thimble transfer driver 223 of the guide-thimble transfer unit 220. The joint of the end plug 10 and the guide thimble 20 is located at a welding position in the welding chamber 100. Next, in the state in which the plasma welding torch 131 is assembled to the torch assembling part 130, argon is supplied into the welding chamber 100 through the argon inflow and outflow ports 141 and 142, and the interior of the welding chamber 100 is maintained under argon atmosphere. A tip of the plasma welding torch 131 is positioned at the welding position. In this state, when the driving motor 310 is driven, the end plug 10 and the guide thimble 20 fixed to the end-plug inserting part 110 and the guide-thimble inserting part 120 are rotated, and the plasma welding torch 131 is operated to weld the joint of the end plug 10 and the guide thimble 20. After the welding is completed, the plasma welding torch 131 moves upward, and the supply of the argon into the welding chamber 100 is interrupted. Next, the guide thimble 20 welded with the end plug is unloaded out of the welding chamber 100, and is transferred to the next process by the guide-thimble transfer unit 220. Although not described in detail, the plasma welding apparatus of the present invention may control the driving elements so as to automatically driven by a separate controller. To this end, a variety of known operation detecting means (sensors) for detecting position and state of the driving elements may be obviously provided. This plasma welding apparatus of the present invention can automatize the welding of the guide thimble and the end plug to increase productivity. Since the plasma welding apparatus of the present invention uses plasma welding, it can be seen that the number of times the welding electrode is exchanged is reduced, and thus the productivity according to the automatization is increased by 100% or more, compared to the case of welding the guide thimble and the end plug using typical TIG welding. Further, to prevent oxidization in the plasma welding process, the interior of the welding chamber is maintained under argon atmosphere rather than under vacuum, and the welding is carried out. Thereby, a complicated configuration for maintaining the vacuum can be excluded. It can be confirmed that an external appearance of the weld zone and soundness of a tensile test and a corrosion test are satisfied only by the supply of argon. Although an exemplary embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
054815762	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. Referring now to FIGS. 1-3, there is shown a vibrating assembly 10 in accordance with the present invention for vibrating an ice basket 20 of a pressurized water reactor (not shown). Vibrating assembly 10 comprises left and right vibrators 100a and 100b and a bracket 200 for operatively connecting vibrators 100a and 100b to the rim or top ring 20a of an ice basket 20. Bracket 200 includes a horizontally-extending first armature portion 210 having first and second downwardly-extending ends 212 and 214 and a middle 216 intermediate first and second ends 212 and 214. First and second clamps 220 and 222 extend downwardly from first armature portion 210 at first and second ends 212 and 214. First and second clamps 220 and 222 are welded or otherwise fixed at notches cut out of first and second ends 212 and 214, respectively. An attachment portion 230 extends vertically upwardly from first armature portion 210. Attachment portion 230 is unitarily formed in a single, generally T-shaped piece with first armature portion 210. Preferably, first armature portion 210 and attachment portion 230 are formed from a 3/4" thick piece of metal plate. Junctions 232 between attachment portion 230 and first armature portion 210 are smoothly rounded to distribute forces concentrating at junctions 232 due to vibrations. A hole 234 is drilled proximate the top center of attachment portion 230 to accommodate a lifting shackle (not shown) used in placement and removal of assembly 10. Bracket 200 further includes a horizontally-extending second armature portion 240 pivotably connected to the bottom of a first armature portion 210. Second armature portion 240 has first and second outwardly-extending ends 242 and 244 and a middle 246 intermediate first and second ends 242 and 244. Third and fourth clamps 250 and 252 extend downwardly from second armature portion 240 at first and second ends 242 and 244, respectively. Third and fourth clamps 250 and 252 are pivotably connected to first and second ends 242 and 244 in a manner to be described in detail hereinafter. Each of first and second clamps 220 and 222 and third and fourth clamps 250 and 252 has top and bottom surfaces 260 and 262, inner and outer surfaces 262 and 264, and opposed end surfaces 268. A groove 270 extends vertically upwardly from each bottom surface 262 and across each of clamps 220, 222, 250, and 252 from one to the other of end surfaces 268. Grooves 270 are arcuate, having a radius matching the curvature of rim 20a of ice basket 20. An internally-threaded cylindrical bore 272 extends inwardly from each inner surface 264 so as to be in communication with each groove 270. A socket head cap screw 274 or similar fastener is inserted into each bore 272 with a locking washer 276 interposed between its head and inner surface 264 in a conventional manner to secure rim 20a in groove 270 in the same manner as a set screw. As will be appreciated by those of ordinary skill in the art, bore 272 can equally well extend from outer surface 266 into communication with groove 270. The manner in which third and fourth clamps 250 and 252 are connected to second armature portion 240 will now be described. First and second ends 242 and 244 of second armature portion 240 are provided with first and second vertically-extending slots, respectively. Socket head cap screws 286 or similar fasteners are inserted through slots 282 and 284 and into bores 280 of third and fourth clamps 250 and 252, with locking washers 288 conventionally interposed between the screw heads and top surfaces 260 of third and fourth clamps 250 and 252. The lateral positions of screws 286 in first and second slots 282 and 284 are adjustable. The angular position of grooves 270 of third and fourth clamps 250 and 252 with respect to the longitudinal axis of second armature portion 240 are also adjustable by pivoting third and fourth clamps 250 and 252 relative to the longitudinal axis of second armature portion 240 before tightening screws 286. In order to connect second armature portion 240 to first armature portion 210, first armature portion 210 is provided with an internally-threaded bore 290 extending upwardly at its center bottom, while second armature portion 240 is provided with a bore 292 through its center. With bores 290 and 292 aligned, a socket head cap screw 294 or similar fastener is inserted through bores 292 and 290 to pivotally connect first and second armature portions 290 and 292 at their respective middles 216 and 246. Again, a locking nut 296 is conventionally interposed between the screw head and the bottom of second armature portion 240. Preferably, left and right vibrators 100a and 100b are air powered vibrators such as CCR 5500 Martin Vibrotor.TM. vibrators, and attachment portion 230 is approximately 5" wide by 12" high to accommodate the mounts 110, such as Cradle lug clamp mounts (part no. 22817) required to clamp vibrators 100a and 100b to the sides of attachment portion 230. Vibrators 100a and 100b and their mounts 110 are bolted on each side of attachment portion 230 in the vertical position. This arrangement provides counter rotation of vibrators 100a and 100b and enhances the vibrating efficiency. When in operation, the vibrating forces are directed down along the sides of ice basket 20. Also preferably, plant air at 60-80 psig is utilized with two air separator-dryers (not shown) to operate vibrators 100a and 100b, producing a total output of approximately 25 CFM. Although this arrangement has proven successful in experimental trials, increasing the total output to 30-50 CFM is also contemplated. It is hypothesized that the additional air supply would increase the vibrating forces transferred to each ice basket 20 and therefore shorten the time interval required to vibrate each ice basket. In use, as indicated above, a lifting shackle (not shown) is attached to attachment portion 230 through hole 234 in order to position vibrating assembly 210 over the top of a selected ice basket 20. Once vibrating assembly 10 is properly oriented with rim 20a of ice basket 20 properly seated within grooves 270, cap screws 274 are tightened to secure vibrating assembly 10 to ice basket 20. Screw 294 fastening second armature portion 240 to first armature portion 210, and screws 286 fastening clamps 250 and 252 to second armature portion 240 are then tightened to complete the installation of vibrating assembly 10. Once all of the screws have been checked for tightness, the air supply can be turned on to start vibrators 100a and 100b. Referring now to FIG. 4, in order to optimize the vibrating capabilities of vibrators 100a and 100b, ice basket 20 is pulled from the top utilizing either an overhead hoist or a Port-a-Power.TM. attached to a fabricated A-frame, depending on the overhead clearance available. Both methods utilize a load cell and the maximum tension is maintained at less than or equal to 3000 pounds pressure. Ice basket 20 also is pushed from the bottom utilizing a Port-a-Power.TM. with a load cell to maintain a compression of less than or equal to 4000 pounds pressure. The combination of tension and compression during the vibrating maximizes the vibrations along the surfaces of ice basket 20. Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. For example, hold down clamps may be used in certain situations to fit over ends 212, 214, 242, and 244 and to extend through the basket 20 below the top ring to prevent the assembly 10 from pulling off of the top ring. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described.
	summary
	claims	1. An apparatus comprising:an electrically conductive substrate having top and bottom surfaces and having vias that cross from the top surface to the bottom surface;a pair of planar first electrodes supported over said top surface; andsecond electrodes having planar surfaces located over said top surface, portions of the planar surfaces being laterally adjacent said planar first electrodes; andwherein one of the second electrodes includes a portion that is located in one of the vias and traverses the substrate. 2. The apparatus of claim 1, wherein the substrate is a doped semiconductor. 3. The apparatus of claim 2, further comprising a dielectric layer located between the second electrodes and the substrate. 4. The apparatus of claim 2, wherein the pair of planar first electrodes are separated by more than 50 micrometers. 5. The apparatus of claim 1,wherein the planar electrodes and second electrodes form plates of a first capacitor;wherein the substrate and the second electrodes form plates of a second capacitor; andwherein a ratio of a capacitance of the second capacitor to a capacitance of the first capacitor is at least as large as 100. 6. The apparatus of claim 5, wherein the ratio of the capacitance of the second capacitor to the capacitance of a first capacitor is at least as large as 500. 7. The apparatus of claim 1, wherein the apparatus is able to trap ions over the planar electrodes in response to the planar electrodes being driven by a voltage having a RF frequency. 8. The apparatus of claim 1, wherein one of the second electrodes is separated from the substrate by 0.5 micrometers or less. 9. The apparatus of claim 1, wherein one of the second electrodes is located between the pair of first electrodes, the one of the second electrodes is separated into segments. 10. The apparatus of claim 9, wherein each segment includes a separate portion that is located in one of the vias and that traverses the substrate. 11. The apparatus of claim 9, wherein one of the second electrodes is surrounded by one or more of the first electrodes. 12. An apparatus, comprising:an electrically conductive semiconductor substrate having a top surface and a bottom surface and having a plurality of planar ion traps; andeach ion trap having first and second electrodes and being configured to trap ions over the top surface of the substrate, each second electrode including a portion that crosses through the substrate. 13. The apparatus of claim 12, wherein the substrate is a doped crystalline semiconductor. 14. The apparatus of claim 13, further comprising a RF driver connected between said substrate and said first electrodes. 15. The apparatus of claim 13, wherein in one of the ion traps, the first electrodes and second electrodes form plates of a first capacitor;wherein in the one of the ion traps, the substrate and the second electrodes form plates of a second capacitor; andwherein a ratio of a capacitance of the second capacitor to a capacitance of the first capacitor is at least as large as 100. 16. The apparatus of claim 13, wherein the substrate is a metal. 17. The apparatus of claim 12, further comprising:a second substrate having a top surface disposed adjacent the bottom surface of the first substrate, the second substrate having circuits for controlling said ion traps and being disposed to make physical and electrical connection with said portions. 18. The apparatus of claim 17, wherein the circuits of the second substrate comprise gates and RF filters. 19. The apparatus of claim 12, wherein a first one of said ion traps is configured to trap an ion at a first trap height above the top surface and a second one of said ion traps is configured to trap the ion at a different second trap height above the top surface.
054141974	description	DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method which includes the steps of incorporating the waste into melted asphalt or other polymer and forming the waste-polymer blend into aggregate pellets for concrete. The pellets (used as aggregate) are coated with powdered siliceous or carbonate material to improve bonding between the pellets and the cementitious matrix. The coated pellets are mixed into a cementitious matrix to form a concrete. This concrete with polymer aggregate is cast into wasteforms for storage or burial. It is desirable to produce a wasteform with the polymer-waste composite in the center of the concrete monolith. To accomplish this, the mold can be placed on a turntable and spun, or otherwise exposed to a centrifugal force, to force the matrix material into a continuous layer on the outside of the wasteform. The polymer-waste pellets typically have a specific gravity near 1.5 while that of the cementitious matrix is greater than 2.0. This difference in density makes it possible to separate the materials by spinning. The wasteform of the present invention is safer and more durable than either of the earlier wasteforms. The new wasteforms can be cast as discrete, self-supporting units of a convenient size and shape that can be stored, transported, and retrieved as required by regulations. This technology does not require that the wasteform be permanently cast in a trench or vault. The waste can be cast as blocks with all exterior surfaces consisting of uncontaminated, normal-strength concrete. No containers or crates should be required to maintain the shape of the wasteform. According to the present invention, the problem of holding soluble salts in a porous medium such as concrete is overcome. The leaching characteristics of the composite are controlled by the polymer encapsulation, not by the cementitious matrix. The major problem with cement-based systems has been the interaction of the wastes with the cement which weakens the resulting solid. By initially isolating the waste, especially the soluble salt, in a polymer, chemical interaction between the cement and the wastes cannot occur. Typically, polymer wasteforms will contain 40-60% waste by mass. It would be useful to have an outer layer of uncontaminated material around the waste to improve waste isolation and, in the case of radioactive wastes, to provide radiation shielding. According to the present invention, the polymer aggregate is disposed in a flowable cementitious mixture and a shielding layer is formed by modifying the wasteform casting process. Because the polymer-waste pellets used as aggregate are much less dense than the unhardened mortar mixture, if the mold is spun during the casting process the heavier mortar mixture will be forced to the outside. When the concrete then hardens, the polymer with the waste enclosed will be concentrated in the center of the concrete mass and a layer of clean, uncontaminated concrete will be formed on the outside of the wasteform. This monolith with the waste concentrated in the center is a wasteform that is safer to handle and less likely to release waste through diffusion. The present inventors know of no other waste disposal technique that involves mixing materials having different densities and separating the materials by spinning. Some asphalt wasteforms have been shown to expand and form surface cracks if they are free to swell in contact with water. The concrete shell can provide confining pressure to prevent the asphalt from expanding and can limit the exposure of the asphalt surface to water. Cement-based wasteforms have been favored in the past because of the relatively high pH maintained in the matrix. The high pH reduces the solubility of many metal salts that are common in wastes and a problem to the environment. For example, cadmium and lead are typically more soluble in acid than alkaline aqueous systems. It has not been possible to develop this type of chemical barrier with asphalt alone. Thus, the present invention provides both the chemical barrier from the high pH and the improved containment of a polymer wasteform. Many materials that are plastic in nature may be used for making pellets. Polyethylene, asphalt, elemental sulfur, and other organic and inorganic materials that are thermoplastic may be used. The waste to be contained and isolated usually begins in the form of a slurry or a solution. The waste is first dried to remove free liquid. The result of this drying step is a dry waste salt. Preferably, a spray evaporator dryer is used which produces a hot, dry salt. The salt product is then mixed or kneaded into the thermosetting polymer after the polymer has been heated to form a liquid or a plastic solid. The resultant mixture is then formed into pellets. Pellets can be formed by making long strips of the waste salt-polymer mixture and cutting the strips into pellet-sized forms. An extruder may be used to form the strips and the strips may be cut as they exit the extruder. Of course, other methods of forming pellets, particularly spherical pellets, can alternatively be used. The pellets can be of various sizes and shapes. For a wasteform monolith weighing approximately 75 pounds, the ideal pellet is roughly equidimensional and is between 0.5 to 2.0 inches in size. Spherical pellets for this size of monolith should have an average diameter between 0.5 and 2.0 inches. This last-mentioned range is a good size for pellets to be used in a monolith which has a size in the range of a 6-inch cube to a 12-inch cube. A monolith size of about a 10-inch cube may be preferred in order to achieve a size which could be handled conveniently. The preferable shape for a monolith would be a cube or a cylinder. The maximum size of a pellet should typically be no larger than one-third of the smallest dimension of the monolith. The pellets are then rolled in or otherwise coated with a fine granular or powdered inorganic compound, such as sand, to improve bonding of the pellet to the cementitious matrix. The pellets are coated with the granular or powdered material while the thermosetting material is in a plastic or semi-solid condition. Heating and tumbling causes adhesion of the grains of powder to the exterior of the pellets. The pellets are then cooled, removed from the powder, and incorporated in the cementitious matrix. Any cementitious or pozzolanic material, fumed silica, ground limestone, fly ash, ground clay, portland cement, sand or ground slag may be used to coat the pellets. Portland cement is a preferred coating substance. The coated pellets are then mixed with a cementitious matrix such as mortar and the mixture is allowed to harden. Alternatively, the mixture may be spun before hardening to force the heavier cementitious matrix to the outside of the monolith. Tests were done with 2-inch diameter by 4-inch long cylinders prepared according to a method of the present invention using a simulated salt waste mixed in asphalt. The tests showed that because there was no loss of strength due to the reactions between the cementitious matrix and the waste it was possible to develop cylinders with unconfined compressive strengths of over 1000 psi using a simple mortar design with Type I-II portland cement. Spinning the samples moved the fresh mortar mixture to the outside of the wasteform. The sample products had a smooth, dust-free exterior surface with no exposed asphalt aggregate. In the above examples salt loadings were below 10% by mass. In a typical concrete, coarse aggregate would form approximately one-half of the volume of a concrete mixture. Assuming a mortar consisting of sand and cement is used as a matrix, replacing the coarse aggregate with pellets of asphalt containing 60% salt would result in a wasteform that contained approximately 20% by mass salt. The wasteforms prepared according to the method of the present invention can have salt loadings comparable to or higher than those wasteforms prepared by mixing waste salt directly into a cementitious matrix. According to the present invention, even salts containing large amounts of chelating agents that would normally require very low salt loading levels (below 1% by mass) can be added into a wasteform without changing the cement content in the matrix. Although the present invention has been described in connection with preferred embodiments, it will be appreciated by those skilled in the art that additions, modifications, substitutions and deletions not specifically described may be made without departing from the spirit and scope of the invention defined in the appended claims.
	claims	1. An apparatus comprising:a bearing plate configured for providing a barrier between a sparger pipe and a structure, wherein the structure is located within a reactor pressure vessel (RPV) of a nuclear power plant; and wherein the pipe comprises at least a lower lug and an upper lug, both of which are located on an outer diameter of the pipe;a lower section including,a first jacking bolt,a first crimp collar configured to secure a position of the first jacking bolt and to affix the first jacking bolt to a designated position,a first lower surface that integrates with the bearing plate, anda second lower surface configured to hold a portion of the pipe, wherein the second lower surface comprises a lower notch configured to receive and mate with the lower lug; andan upper section slidably connected to the lower section, wherein the upper section includes,a hole, wherein the first jacking bolt is configured to move through the lower section, then the hole, and then terminate at a portion of the bearing plate so as to secure the upper section to the lower section,a first upper surface that integrates with the bearing plate, anda second upper surface that is configured to hold a portion of the pipe, wherein the second upper surface comprises an upper notch that is configured to receive and mate with the upper lug,wherein the bearing plate, the lower section, and the upper section are configured to secure the feedwater sparger pipe, andwherein the lower section and the upper section are configured to cooperatively secure the pipe at a distance from a facing surface of the bearing plate, and to allow for dampening of a vibration experienced by the pipe. 2. The apparatus of claim 1, wherein the upper section comprises:a second jacking bolt for affixing the upper section to the bearing plate, wherein the second jacking bolt is secured by a second crimp collar; andat least one pinch bolt for clamping the upper section and the lower section to the pipe, wherein the at least one pinch bolt is secured by the second crimp collar. 3. The apparatus of claim 2, further comprising a pinch plate, wherein the pinch plate provides a bearing surface between the at least one pinch bolt and the second jacking bolt. 4. The apparatus of claim 3, wherein the upper section comprises a cavity that allows for a portion of the second crimp collar, a portion of the bearing plate, and a portion of the pinch plate to reside. 5. The apparatus of claim 1, wherein a length of the bearing plate extends beyond a combined length of the upper section and the lower section when the upper section is integrated with the lower section. 6. The apparatus of claim 1, wherein a compressive load applied to the upper section and the lower section by at least one pinch bolt is configured to restrict movement of the first lug and the second lug. 7. The apparatus of claim 6, wherein the compressive load applied to the upper section and the lower section by the at least one pinch bolt is configured to restore preload onto the sparger pipe. 8. A system comprising:a nuclear fuel core comprising a plurality of fuel bundle assemblies;a inlet;a sparger pipe comprising at least a lower lug and an upper lug that are located on an outer diameter of the pipe;a core spray line; anda clamp comprising:a bearing plate configured for providing a barrier between a sparger pipe and a structure, wherein the structure is located within a reactor pressure vessel (RPV) housing the nuclear fuel core; and wherein the pipe comprises at least a lower lug and an upper lug, both of which are located on an outer diameter of the pipe;a lower section including,a first jacking bolt,a first crimp collar configured to secure a position of the first jacking bolt and to affix the first jacking bolt to a designated position,a first lower surface that integrates with the bearing plate, anda second lower surface that holds a portion of the pipe, wherein the second lower surface comprises a lower notch that receives and mates with the lower lug; andan upper section slidably connected to the lower section, wherein the upper section includes,a hole, wherein the first jacking bolt is configured to move through the lower section, then the hole, and then terminate at a portion of the bearing plate so as to secure the upper section to the lower section,a first upper surface that integrates with the bearing plate, anda second upper surface that holds a portion of the pipe, wherein the second upper surface comprises an upper notch that receives and mates with the upper lug,wherein the sparger pipe is secured by the bearing plate, the lower section, and the upper section, andwherein the lower section and the upper section cooperatively secure the pipe at a distance from a facing surface of the bearing plate, and allows for dampening of a vibration experienced by the pipe. 9. The system of claim 8, wherein the upper section comprises:a second jacking bolt for affixing the upper section to the bearing plate, wherein the second jacking bolt is secured by a second crimp collar; andat least one pinch bolt for clamping the upper section and the lower section to the sparger pipe, wherein the at least one pinch bolt is secured by the second crimp collar. 10. The system of claim 9, further comprising a pinch plate, wherein the pinch plate provides a bearing surface between the at least one pinch bolt and the second jacking bolt. 11. The system of claim 10, wherein the upper section comprises a cavity that allows for a portion of the second crimp collar, a portion of the bearing plate, and a portion of the pinch plate to reside therein. 12. The system of claim 8, wherein the bearing plate extends beyond the upper section and the lower section when the upper section is connected to the lower section. 13. The system of claim 11, wherein the sparger pipe comprises a plurality of lugs and a first lug mates with a portion of upper section and a second lug mates with a portion of the lower section; wherein a compressive load applied to the upper section and the lower section by the at least one pinch bolt restricts the movement of the first lug and the second lug. 14. The system of claim 13, wherein the compressive load applied to the upper section and the lower section by at least one pinch bolt applies a preload onto the sparger pipe.
039322122	summary
056235291	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are described below with reference to the drawings. Embodiment 1 FIG. 1 shows the construction of an SOR exposure system in accordance with a first preferred embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an SOR light source apparatus including a charge storage ring, the synchrotron radiation emitted from the charge storage ring 1 being supplied to beam lines 21 to 28 connected to exposure apparatus 31 to 38 for exposing wafers, and beam lines 4a and 4b connected to exposure apparatus 5a and 5b, respectively, for duplicating X-ray masks. In this embodiment, the mask duplicating beam lines 4a and 4b are longer than the beam lines 21 to 28 and have a smaller divergence angle (i.e., higher resolving power for exposure transfer). FIG. 2 illustrates the construction of the beam lines 21 to 28 to which the wafer exposure apparatus 31 to 38 are respectively connected, the beam lines 21 to 28 having the same construction. The synchrotron radiation 51 emitted from an emission point 50 is enlarged and vertically reflected by a convex X-ray mirror 53 in a mirror chamber 52. The radiation 51 is then passed through a vacuum duct 54, a vacuum partition 55, and a shutter unit 56 and is projected onto a mask 58 to transfer a mask pattern to a wafer 59 by exposure. The inside of an exposure unit 57 containing the mask 58 and the wafer 59 has a He atmosphere under pressure reduced to about 150 torr. The vacuum partition 55 is made of a Be foil having a thickness of about 15 .mu.m so as to decrease the attenuation of the illumination light within the region from the vacuum partition 55 to a photosensitive material on the wafer 59. The above illumination optical system is designed so that the intensity of the illumination light satisfies resolving power and productivity (throughput) which are required for manufacturing wafers. In this construction, since the distance from the emission point 50 to the X-ray mirror 53 is, for example, 3 m, and the distance from the X-ray mirror 53 to the mask 58 is, for example, 5 m, the distance from the emission point 50 to the mask 58 is 8 m. If the exposure region of the wafer 59 has, for example, a 30-mm square rectangular form, the horizontal divergence angle is 3.75 mrad, and the vertical divergence angle is 6 mrad. If the dispersion of the gap dimension between the mask 58 and the wafer 59 is 3 .mu.m, a distortion of 18 nm occurs in transfer of the pattern. Although the intensity of the illumination light depends upon the intensity of the synchrotron radiation and the sensitivity of the photosensitive material on the wafer used, the illumination optical system is designed so that the intensity of the illumination light satisfies the condition that the exposure time is about 0.3 to 1 second. Table 1, below, shows details of the design of the illumination system in the wafer exposure apparatus shown in FIG. 2. The X-ray mirror used is made of silicon carbide and is processed so that the reflecting surface has a surface roughness of 1 nm (rms), and the angle of incidence of the main SOR beam on the reflecting surface is 15 mrad. This mirror decreases the intensity of the short wavelength component of the SOR beam. The vacuum partition made of a 15-.mu.m Be foil decreases the intensity of the long wavelength component. The items of this optical system are determined so that an intensity and contrast sufficient for practical use are obtained in the intensity profile of the exposure light absorbed by a chemical sensitization type resist on the wafer when the exposure light is applied to the resist through an X-ray mask comprising a gold absorber pattern having a thickness of 0.6 .mu.m and a silicon nitride membrane having a thickness of 2 .mu.m. FIG. 3 shows the absorption intensity distribution of the resist in the illumination system having the items shown in Table 1. In FIG. 3, a solid line shows the spectrum of the exposure light transmitted by a portion of the mask without the gold absorber pattern, and a dotted line shows the spectrum of the exposure light transmitted by a portion with the gold absorber. The absorption intensity of the exposure light is obtained by integrating each of the spectra shown in FIG. 3 with wavelength. The absorption intensity in the portion without the gold absorber is approximately 2.13 mW/cm.sup.2, and the absorption intensity in the portion with the gold absorber is approximately 0.176 mW/cm.sup.2. If the optimum amount of the light absorbed by the resist required for transfer is 60 J/cm.sup.3, since the thickness of the resist is 1 .mu.m, the exposure time is approximately 2.8 seconds. In addition, the contrast between the pattern portion and the non-pattern portion is 12.1:1. FIG. 4 illustrates the construction of the beam line 4a (or 4b) to which the X-ray mask duplicating exposure apparatus 5a (or 5b) is connected. The synchrotron radiation 71 emitted from an emission point 70 is reflected twice by two plane mirrors 73 and 74 in a mirror unit 72. The radiation 71 is then passed through a vacuum duct 75 and a vacuum partition 76 and is projected onto an original mask 77 to transfer by exposure an original mask pattern to a mask substrate 78 to be exposed. In this apparatus, the distance from the light source to the mask is, for example, 30 m, and the horizontal divergence angle is 1 mrad. The whole exposure region is exposed by scanning the original mask 77 and the mask 78 to be exposed vertically to the illumination light without vertically enlarging by a mirror. In this case, the illumination light is made parallel in the vertical direction. Since the mask substrate which is flatter than the wafer subjected to various processes is used as a substance to be exposed, the dispersion of the gap dimension can be set to a small value. For example, if the dispersion of the gap dimension is 2 .mu.m, the resultant distortion is 2 nm. Table 2 shows details of a design of the illumination system in the X-ray mask duplicating exposure apparatus shown in FIG. 4. The two X-ray mirrors 73 and 74 are made of silicon carbide and are processed so that the reflecting surface of each has a surface roughness of 4 nm (rms), and the angle of incidence of the main SOR beam on each of the reflecting surfaces is 26 mrad. These mirrors have low reflectance on the short wavelength side and thus have a central wavelength longer than the central wavelength of the exposure light obtained by the wafer exposing beam lines. The vacuum partition 76 is made of a material of polyimide having a thickness of 0.5 .mu.m, and separates the He atmosphere under reduced pressure in the exposure apparatus from the vacuum in each of the beam lines. The polyimide has higher transmittance than Be on the long wavelength side, and can thus transmit the long-wavelength illumination light selected by the X-ray mirror. Although the illumination system configured as shown in Table 2 exhibits low illumination intensity and long wavelength, as compared with the illumination system shown in Table 1, it is possible to supply illumination light more suitable for the mask duplicating exposure apparatus for the reasons below. A first reason is that since the illumination intensity is low, the amount of the heat generated due to exposure energy in the original mask and the duplicate mask substrate used as the substrate to be exposed can be decreased, thereby decreasing thermal distortion and increasing the precision of the pattern transfer position. This is particularly effective for the case where the substrate to be exposed for the duplicate mask comprises a thin film. A second reason is that although a long wavelength causes deterioration in the resolving power due to the effect of the light diffracted by the mask, this can be compensated for by decreasing the proximity gap because the duplicate mask substrate as the substrate to be exposed has higher flatness than that of the wafer which was subjected to various processes. In addition, with a long wavelength, since the range of the secondary electrons generated by the X-ray used as the exposure beam is short, the resolving power is increased. For these reasons, high resolving power can be obtained by setting the proximity gap to a small value. The absorber pattern of the original mask is produced by drawing the pattern on the resist using an electron beam drawing exposure apparatus, and then etching or plating. When the thickness of the finally formed absorber is as small as possible, the stress strain generated can be decreased. The thickness distribution of the absorber can also be decreased, and the precision of the pattern line width transferred can be improved. Further, when the pattern is produced by the plating method, if the absorber has a thickness of, for example, about 0.2 .mu.m, a single-layer resist can be used in electron beam drawing. When the pattern is produced by etching, the process can be simplified. In this way, in manufacturing the original mask, the mask with higher precision can easily be manufactured by decreasing the thickness of the absorber pattern. The items of the illumination system shown in Table 2 are determined so as to select exposure light having a wavelength which can achieve a satisfactory contrast even if the gold absorber of the original mask has a thickness of 0.2 .mu.m. If the line width dimension of the pattern is 0.2 .mu.m, the ratio of the line width to the thickness, i.e., the aspect ratio, is 1. A low aspect ratio is also advantageous for manufacturing the original mask. The X-ray mask with a higher aspect ratio can be duplicated by using the original mask. FIG. 5 shows the absorption intensity distribution of the resist in the illumination system having the items shown in Table 2. In FIG. 5, a solid line shows the spectrum of the exposure light transmitted by a portion of the mask without the gold absorber pattern, and a dotted line shows the spectrum of the exposure light transmitted by a portion with the gold absorber. The comparison with FIG. 3 reveals that the central wavelength of the spectra is longer than that shown in FIG. 3. The design having the items shown in Table 2 thus enables the achievement of illumination light having a longer wavelength. The value of absorption intensity of the exposure light is determined by integrating each of the spectra shown in FIG. 5 with wavelength. The absorption intensity in the portion without the gold absorber is approximately 0.0113 mW/cm.sup.2, and the absorption intensity in the portion with the gold absorber is approximately 0.000818 mW/cm.sup.2. The contrast between the pattern portion and the non-pattern portion is thus 13.8:1. The light having a short wavelength contained in the synchrotron radiation scatters the secondary electrons emitted from the mask substrate used as the material to be exposed and sensitizes the photosensitive material, thereby deteriorating the resolving power in duplication of the mask. The embodiment shown in FIG. 4 thus uses plane mirrors 73 and 74 for removing the adverse short-wavelength component. However, a construction without such reflecting mirrors is, in some cases, effective from the viewpoint of the characteristics of the synchrotron radiation. In this case, the construction of a mask duplicating beam line is as shown in FIG. 6. The beam line shown in FIG. 6 does not have the mirror unit containing the plane mirrors shown in FIG. 4. In FIG. 6, reference numeral 90 denotes a shielding member which has a slit-formed opening for passing as a light flux 71' a portion of the upper half of the synchrotron radiation in the vertical divergence therethrough. The shielding member 90 is made of a metal having a thickness sufficient to shield X-rays and has an edge portion in a form which is designed so that the surface area parallel with the beam is decreased for decreasing scattering of the illumination light. In this way, the central portion having the short-wavelength component of relatively high intensity is removed, and the portion having a small amount of short-wavelength component is used as the illumination light. FIG. 7 is a drawing illustrating details of the construction of the X-ray mask duplicating exposure apparatus 5a (or 5b). A mask substrate 78 to be exposed has a frame 80 for supporting the substrate, the frame 80 being held by a vacuum chuck 81. The vacuum chuck 81 is connected to a holding member 83 by a plate spring mechanism 82. A gap setting driving mechanism 84 is provided at three positions in order to move the vacuum chuck 81 in parallel with the plate spring mechanism 82 along the optical axis of the illumination light. The driving amounts of the gap setting driving mechanism 84 are set to different values so that the inclination of the vacuum chuck 81 can be adjusted together with movement of the vacuum chuck 81 along the optical axis. The gap between the original mask substrate 77 and the mask substrate 78 to be exposed can be controlled with high precision by using the detected value of a gap detector 85. The original mask substrate 77 is attached to a vacuum chuck 79 which is connected to a frame 86. A locking actuator 87 is provided between the frame 86 and the holding member 83 so that the frame 86 and the holding member 83 are connected together with high stiffness by driving the actuator 87 during exposure transfer. The original mask substrate 77 and the mask substrate 78 to be exposed are thus substantially integrated, and are scanned over the whole exposure region at right angles to the illumination light. Since the original mask substrate 77 and the mask substrate 78 to be exposed are mechanically locked in scanning exposure, the relative positional deviation between both substrates, which is caused by vibration or the like during scanning, can be decreased, thereby providing an X-ray mask with higher precision. Embodiment 2 FIG. 8 is a drawing illustrating the construction of a second preferred embodiment of the present invention. The same members as those shown in FIG. 2 are denoted by the same reference numerals. The apparatus of this embodiment is configured so as to be used for both producing semiconductor devices and duplicating masks. The construction of the system comprises a plurality of exposure apparatus radially connected to a common SOR light source apparatus, as in the construction shown in FIG. 1. An X-ray intensity attenuation means 100 shown in FIG. 8 is provided on any one or all of the beam lines of the exposure apparatus. FIGS. 9 and 10 are drawings illustrating details of the construction of the intensity attenuation means 100. The inside of a chamber 102 is in a state under the same reduced pressure as in the beam port. When a semiconductor is exposed, i.e., when high X-ray intensity is required for obtaining high productivity, an attenuation filter 103 is retracted from the use region (exposure region) 101 of the illumination light, as shown in FIG. 9, so that the X-rays are introduced into the exposure apparatus without being attenuated. On the other hand, when an X-ray mask is duplicated, i.e., when a high resolving power is required, the attenuation filter 103 is placed on the use region 101 of the illumination light, as shown in FIG. 10, so that the X-rays attenuated in intensity are introduced into the exposure apparatus. The two states are switched by driving a cylinder 104. Since heat is generated in the attenuation filter due to absorption of a portion of X-ray energy in the state shown in FIG. 10, wafer cooling means 105 is provided for preventing the temperature from rising due to the heat generated. The attenuation filter 103 has a filter comprising a thin plate of silicon, silicon nitride, silicon carbide, beryllium or the like, and a frame member for fixing the filter. The thickness of the filter may be set so that thermal strain is within a desired permissible range in view of the intensity of the illumination light, the heat transfer passage from the original X-ray mask to the chuck, etc. The mechanism for attenuating X-ray intensity is not limited to the above form, and some modified examples can be considered. FIG. 11 is a drawing illustrating another example of the attenuation filter. This example comprises a plurality of filters which have different attenuation factors and which are provided in a frame member 110. The filter selected from the plurality of filters is placed on the use region of the illumination region. The X-ray illumination light having an appropriate intensity can be obtained by switching the filters. FIG. 12 is a drawing illustrating a further example of the attenuation filter. A filter 115 having a transmission region with a width greater than the width of the use region of the illumination light is provided on the illumination optical path, and the angle of the filter 115 with respect to the illumination light is adjusted. Since the apparent thickness of the filter 15 can be changed during transmission of the illumination light, the intensity of the illumination light can be arbitrarily attenuated. FIGS. 13A and 13B are drawings illustrating a still further example for attenuating the apparent intensity of the illumination light. Two shielding plates 120 and 121 having a substantially semicircular form are provided in the illumination optical path in order to shield the illumination light so as to pass the illumination light through the gap between the two shielding plates. The two shielding plates are simultaneously rotated while maintaining the gap therebetween. If the gap is moved at a speed at which the time required for moving the gap through the exposure region is sufficiently smaller than the time constant of the heat transfer passage from the X-ray mask to the chuck, the substantial intensity of the illumination light applied to the exposure region is attenuated. The attenuation factor can also be adjusted by adjusting the dimension of the gap. In FIG. 13A, the gap is moved by synchronously rotating the two shielding means using motors 122 and 123, respectively, and the gap dimension is adjusted by adjusting the rotational phases of the two motors. In the above embodiments, since the intensity of the illumination light in an X-ray exposure apparatus which uses the common light source for synchrotron radiation or the like can be adjusted without influences on the illumination light intensity in another exposure apparatus, a high resolving power can be obtained by attenuating the X-ray intensity in duplication of the X-ray mask, and a high productivity can be obtained by increasing the X-ray intensity in wafer exposure. Not only when the X-ray mask is duplicated but also when a device with higher precision is produced, i.e., when high precision exposure is desired in spite of the need for much exposure time, the X-ray intensity may be attenuated, and a semiconductor device with a higher degree of integration can be manufactured. Embodiment 3 An embodiment of the device manufacturing method using the above-described exposure apparatus is described below. FIG. 14 shows a manufacture flowchart of a microdevice (an IC or LSI semiconductor chip, a liquid crystal panel, CCD, a thin-film magnetic head, a micromachine, etc.). The circuit of the device is designed in Step 1 (circuit design). A mask having the designed circuit pattern formed thereon is manufactured in Step 2 (mask manufacture). The manufacture of the mask employs the above-described exposure apparatus. On the other hand, a wafer is manufactured by using material such as silicon or the like in Step 3 (wafer manufacture). Step 4 (wafer process) is referred to as a pre-process for forming an actual circuit on the wafer by the lithographic technique using the prepared mask and wafer. Next Step 5 (assembly) is referred to as a post-process for forming a semiconductor chip using the wafer manufactured in Step 4, the post-process comprising the assembly step (dicing, bonding), the packaging step (chip sealing) and so on. In Step 6 (inspection), tests such as a device operation confirmation test, durability test, etc., are performed on the device manufactured in Step 5. The device is completed through these processes and then delivered (Step 7). FIG. 15 shows details of the flowchart of the above wafer process. The surface of the wafer is oxidized in Step 11 (oxidation). An insulating film is formed on the surface of the wafer in Step 12 (CVD). Electrodes are formed on the wafer by evaporation in Step 13 (electrode formation). An ion is implanted into the wafer in Step 14 (ion implantation). A sensitizing agent is coated on the wafer in Step 15 (resist treatment). The circuit pattern of the mask is baked and exposed by the above exposure apparatus in Step 16 (exposure). The exposed wafer is subjected to development in Step 17 (development). Portions other than the developed resist image are cut off in Step 18 (etching). The unnecessary resist after etching is removed in Step 19 (resist separation). These steps are repeated to form a circuit pattern in multiple layers on the wafer. The use of the manufacturing method of this embodiment enables manufacture of a device which cannot be easily manufactured by a conventional method, with a high degree of integration and high productivity. TABLE 1 ______________________________________ Example of Illumination System for Wafer Exposure Apparatus ______________________________________ Light source Electron energy 700 MeV Orbital radius 0.582 m Stored current 300 mA Beam size (.sigma..sub.y) 0.5 mm Beam divergence angle (.sigma..sub.y') 0.2 mrad Critical wavelength 9.49.ANG. Mirror Reflecting surface material SiC Surface roughness 10 .ANG. Surface shape Cylindrical Radius of curvature 40 m Incident angle 15 mrad X-ray Material Be window Thickness 15 .mu.m Mask Supporting film material Si.sub.3 N.sub.4 Thickness 2 .mu.m Resist Type Chemical amplified type Thickness 1 .mu.m Arrangement SOR-mirror 3 m SOR-mask 8 m X-ray window-mask 0.4 m ______________________________________ TABLE 2 ______________________________________ Example of Illumination System for Mask Duplicating Exposure Apparatus ______________________________________ Light source Electron energy 700 MeV Orbital radius 0.582 m Stored current 300 mA Beam size (.sigma..sub.y) 0.5 mm Beam divergence angle (.sigma..sub.y') 0.2 mrad Critical wavelength 9.49.ANG. First mirror Reflecting surface material SiC Surface roughness 40 .ANG. Surface shape Plane Incident angle 26 mrad Second Mirror Reflecting surface material SiC Surface roughness 40 .ANG. Surface shape Plane Incident angle 26 mrad X-ray Material polyimide window Thickness 0.5 .mu.m Mask Supporting film material Si.sub.3 N.sub.4 Thickness 2 .mu.m Resist Type Chemical amplified type Thickness 3 .mu.m Arrangement SOR-first mirror 3 m SOR-second mirror 4 m SOR-mask 30 m X-ray window-mask 0.4 m ______________________________________
	claims	1. A radiation measurement instrument calibration facility capable of lowering scattered radiation and background radiation, adapted to be disposed inside a laboratory, the facility comprising:a shielding device, for shielding the scattered radiation and background radiation inside the laboratory, being configured with an inlet, an outlet and a cavity in a manner that the inlet, the outlet and the cavity are arranged in communication with each other while the to-be-calibrated instrument being placed in the cavity and the cavity being in communication with two openings formed respectively on two sides of the shielding device that are perpendicular to the inlet and the outlet;an electric door unit, for positioning the shielding device and the to-be-calibrated instrument as well as controlling the movement of two door panels for enabling the two to wall the two openings of the shielding device;a control unit, for controlling the operation of the electric door unit in a remote manner;a multi-source irradiator, configured with several radiation sources of different intensity, capable of emitting a primary radiation beam while allowing the radiation intensity of the same to be variable according to the radiation source that is selected from the irradiator for the emission;a collimator, for controlling the radiation field size of the primary radiation beam while enabling the primary radiation beam to travel into the shielding device through the inlet and out of the same through the outlet;a carrier, for carrying the shielding device and the electric door unit while adjusting the levels of the two; anda radiation baffle, for reducing the amount of background radiation entering the shielding device through the outlet. 2. The calibration facility of claim 1, wherein the cavity of the shield device further has an illuminator device configured therein. 3. The calibration facility of claim 1, wherein the cavity of the shield device further has a video monitor configured therein. 4. The calibration facility of claim 1, wherein the cavity of the shield device further has a thermometer configured therein. 5. The calibration facility of claim 1, wherein the cavity of the shield device further has a hygrometer configured therein. 6. The calibration facility of claim 1, wherein the cavity of the shield device further has a pressure meter configured therein. 7. The calibration facility of claim 1, wherein the electric door unit further comprises:a rail, for guiding the two door panels to move along therewith; anda step motor, for power and driving the two door panels to move. 8. The calibration facility of claim 1, wherein the to-be-calibrated instrument is received inside the cavity of the shielding device, while allowing the to-be-calibrated instrument to be fixed securely by the use of the fixing rack that are mounted on the external of the to-be-calibrated instrument. 9. The calibration facility of claim 1, wherein each of the shield device, the collimator and the radiation baffle is made of a high density metal and the high density metal is a metal selected from the group consisting of: lead and stainless steel.
	abstract	Articles of manufacture and a method of how to utilize the same in order to create a radiation shielding barrier wall assembly. A metal stud and a metal support bar and a metal restraining bar and a prefabricated radiation shielding lead panel whereby the assembly of these components in the manner as directed and in conjunction with commercially available preexisting metal stud components will result in all radiation shielding lead panels overlapping at all interior field joints, and will result in no punctures or damage in any way to the radiation shielding lead created by the attachment method, creating a radiation shielding leak-proof metal stud system.
042882907	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 2, a platform 5 is rotatably mounted on an annular rail 4 supported by supporting members 3 projecting from the inner peripheral wall of a cylindrical working chamber 1 located below the reactor pressure vessel. The platform 5 is provided with a longitudinal cavity 5a in its central portion and rails 20 on which a traveling carriage 21 is mounted are laid along both sides of the cavity 5a. The cavity 5a has a volume sufficient to accommodate a carriage 8 for conveying a control rod drive mechanism 7 into and away from the cavity 5a. The travelling carriage 21 has a U-shaped cross-section to ride on the both rails 20 and the forward top wall of the carriage is broken away in FIG. 2. A beam 22 is pivotably supported by a pin 21c between the side walls 21a and 21b of the forward portion of the carriage 21 to be tilted about the pin 21c between the vertical and horizontal positions by a drive mechanism 23 mounted on the carriage 21. FIG. 2 shows the vertical position of the beam 22, in which the upper end of the beam 22 projects beyond the upper surface of the traveling carriage 21 and the lower end thereof projects downwardly through the cavity 5a of the platform 5. When the beam 22 is tilted to the horizontal position, it is housed in the traveling carriage 21. Sprockets 24a and 25a are attached to both sides of the longitudinal ends of the beam 22 between which chains 25 are streached, respectively, and a carrier 26 is located to engage the chains 25 and to be movable along the beam 22. As shown in FIG. 3, the U-shaped beam 22 is provided with flanges 27 at the edges of both side walls and a pair of rollers 28a and rollers 29a are disposed at rear end sides of the carrier 26, respectively, so as to clamp the flanges 27. An arm 30 is connected at its both ends to the chains 25 streched along the both sides of the beam 22, and the arm 30 is pivotally supported by a pin 29 at the center portion of the rear end of the carrier 26. When the chains 25 are driven, the rollers 28a and 28b roll along the both sides of the flanges 27 thereby vertically moving the carrier 26 along the beam 22. At this time, even if the chains on both sides are driven at different speeds, since the arm is pivotably supported by the pin 29, the carrier 26 can be moved in an inclined state. The carrier 26 not only directly supports the control rod drive mechanism 7 to be removed but also holds a device for loosening and clamping bolts which connect the control rod drive mechanism 7 to the housing 10. This device 32 is called "a bolt mounting device 32" hereinafter. The beam 22 is further provided with a holding arm 33 at a position suitable for being housing in the interior of the U-shaped beam 22 so as not to disturb the movement of the carrier 26 and for supporting the control rod drive mechanism 7 as occasion demands by being projected from the interior of the beam 22. More particularly, as shown in FIGS. 4 and 5, to cooperate with this holding arm 33, a rocking lever 35 pivotable about a pin 32 extending in a direction normal to the axis of the beam 22 is mounted within the beam 22 and an operation bar 36 extending in a direction normal to the axis of the rocking lever 35 is attached to a boss 35a provided at the front end of the lever 35 to be slidable only in the axial direction. A pair of jaws 38 are pivotably secured to the front end of the bar 36 by means of pins 37 extending substantially parallel with the axis of the beam 22. The jaws 38 are connected through link members 39 to wings 40 at both sides of the boss 35a, respectively, whereby the jaws 38 are opened or closed by the movement of the boss 35a to hold firmly or release the control rod drive mechanism 7. The forward (leftward in FIG. 5) movement of the operation bar 36 is limited by the engagement of stopping members 41 projecting from the inner surfaces of the side walls of the beam 22 with an abutting member 42 attached to the rear end of the bar 36. A compression spring 43 is disposed between the boss 35a and the jaw attaching member 36a of the operation bar 36 so as to urge the boss 35a to engage front surface of the abutting member 42. A link member 45 has one end pivotably secured to the rocking lever 35 through a pin 44 and the other link member 48 also has one end pivotably attached through a pin 47 to a bracket 46 which is secured to the beam 22. The inner ends of these link members 45 and 48 are pivotably connected by a pin 52 mounted on the front end of a piston rod 51 of a hydraulic cylinder-piston assembly 50 pivotably supported by a bracket 49 on the side surface of the beam 22. This structure is a so called toggle joint. FIG. 4 shows the closed state of the jaws 38 and in this stage, the rocking lever 35 is rotated forwardly (rightwardly in FIG. 4) by the cooperation of the hydraulic cylinder-piston assembly 50 and the link members 45 and 48. Concurrently, therewith, the operation bar 36 is also moved rightwardly by the action of the compression spring 43 till the member 42 abuts against the stopping members 41 and then the both jaws 38 are rotated to be closed about the pins 37 through the link members 39, respectively, to hold the control rod drive mechanism 7 therebetween. When the rocking lever 35 is slightly rotated counter-clockwisely from the state shown in FIG. 4, the jaws 38 are slightly opened to release the control rod drive mechanism 7 so as to serve as a guide member therefor. Then, when the rocking lever 35 is further rotated counter-clockwisely, the boss 35a abuts against the abutting member 42 to fully open the jaws 38 and moves leftwardly together with the operation bar 36 to accommodate the jaws 38 into the beam 22. Referring again to FIG. 2, a rail assembly 53 on which a carriage 54 is traveled to convey the bolt mounting device 32 is suspended from the lower portion of the platform 5 and the rail assembly 53 comprises two rails 53a horizontally arranged on both sides of the beam 22. The carriage 54 can travel on the rails 53a by, for example, a drive mechanism 54a shown in FIG. 2, and the carriage 54 is provided with a recess 54b having an opening facing to the beam 22 to receive the bolt mounting device 32 threin. The bolt mounting device 32 is engaged with and supported vertically by pins 32a provided on the upper surface of the carriage 54 and the device 32 is further provided with pins 32b adapted to engage with notches 26b formed at the upper edges of the side walls of the carrier 26. Therefore, the device for loosening or clamping the bolts which interconnect the control rod drive mechanism 7 and the housing 10 operates not only to loosen or clamp the bolts, but also to receive and treat reactor water which may leak from the housing 10 of the reactor core when the control rod drive mechanism 7 is removed therefrom. The bolt mounting device 32 comprises a cylindrical casing 60 in which there is disposed a drive mechanism for simultaneously driving a plurality of spanners. With reference to FIG. 6 through FIG. 13, the bolt mounting device 32, particularly the cylindrical casing 60 thereof will be described in detail. A reversible electric motor 61 for driving the spanners is provided with an output shaft 61a on which a torque limit member 62 and a reduction gear 63 are mounted. In the casing is housed a gear box 64, and a differential gearing 65 in the gear box 64 is mounted on the output shaft 63a of the reduction gear 63. Spanners 66a and 66b are attached to the rotary shaft 65a and 65b of the differential gearing 65 which is constructed as shown in detail in FIGS. 6 through 9, in which disc plates 69 and 70 are mounted on the output shaft 63a through bearings 67 and 68, respectively, and internal gears 69a and 70a and external gears 69b and 70b are formed on the disc plates 69 and 70, respectively. An arm 71 is secured to the output shaft 63a and provided with lateral projections to which the base portions of pins 72 and 73 are embedded. Pinions 74 and 75 having different thickness are rotatably mounted about the pins 72 and 73 to mesh with each other. The pinions 74 and 75 also mesh with the internal gears 69a and 70a, respectively, and the external gears 69b and 70b also mesh with gears 76 and 77 mounted on the rotary shafts 65a and 65b, respectively. These gears 76 and 77 are rotated in the same direction. FIGS. 10 and 11 show the detail of the torque limit member 62 which is assembled with a rotating cylindrical member 78 mounted on one end of the output shaft 61a. A cover 79 is secured to one end of the cylindrical member 78 and bearings 80a and 80b are located at the bottom of the cylinder 78 and the cover 79 respectively so as to rotatably support a follow-up shaft 62a. A one-way clutch 81 is secured to the follow-up shaft 62a near the bearing 80a and when the cylindrical member 78 is rotated in a direction shown by an arrow A in FIG. 11, rollers 81a are moved to engage with the one-way clutch 81, thus rotating the follow-up shaft 62a. On the other hand, when the cylindrical member 78 is rotated in the opposite direction, the rollers 81a does not engage the clutch 81, thus not rotating the follow-up shaft 62a. Furthermore, the cylindrical member 78 is provided with a spline groove 82 on its inside peripheral surface. Three circular friction clutch plates 83 provided with splines engage the spline groove 82 and are axially pressed by means of coil springs 85 through friction plates 84 provided with spline grooves 84a respectively. These grooves 84a engage the splines formed on the follow-up shaft 62a to be axially slidable and rotatable with the shaft 62. Accordingly, the torque limit member 62 operates in a manner that when the cylindrical member 78 is rotated by the rotation of the output shaft 61a, the rotating power is transmitted to the follow-up shaft 62a through the clutch plates 83 and the friction plates 84, but the rotation of the follow-up shaft 62 is stopped when a predetermined load is applied to the shaft, i.e., when the bolts are clamped to its limit state. In this case, the cylinder 78 rotates idly. Now, when it is intended to clamp two bolts connecting the control rod drive mechanism 7 and the housing 10, the spanners 66a and 66b are previously engaged with the corresponding bolts and when the electric motor 61 is then rotated, the output shaft 63a drives the differential gearing 65 through the torque limit member 62 and the reduction gear 63. Namely, when the shaft 63a is clockwisely rotated, the arm 71 is also rotated so as to counter-clockwisely rotate the pinions 74 and 75 about the pin shafts 72 and 73, respectively. However, these pinions 74 and 75 are meshing with each other and thus, the counterclockwise rotations of the pinions are restrained, so that the internal gears 69a and 70a are clockwisely rotated and the spanners 66a and 66b attached to the rotatary shafts 65a and 65b clamp the bolts. In a case where there exists some difference between the clamping strokes either one of the bolts would be clamped firstly. Assuming now that the spanner 66a firstly clamps the corresponding bolt to the final clamping stroke, the rotation of the gear 76 stops and the internal gear 70a also stops its rotation. Then, the pinion 75 meshing with this internal gear 70a revolves along the inner surface of the gear 70a to drives the pinion 74 engaging the pinion 75, whereby the internal gear 69a meshing with the pinion 74 is rotated at an increased speed and the gear 77 engaging the external gear 69b is rotated thereby rotating the spanner 66b and clamping the other bolt to the final clamping stroke at a high speed. Upon reaching a torque more than a predetermined value, regardless the drive of the motor 61, the torque limit member 62 slips, and the rotation of the internal gear 69a stops, thus completely clamping the bolts. As a characteristic feature of the differential gearing 65, the driving force is equally applied to the internal gears 69a and 70a, so that if the slip starting torue of the torque limit member 62 were initially regulated to a torque suitable for clamping the bolts, the final clamping torque could be properly adjusted thereby uniformly clamping two bolts, respectively, even if there exists a difference between the clamping strokes of two bolts to be clamped by the spanners 66a and 66b. Within the casing 60 of the bolt mounting device 32, is set a television camera, not shown, below the spanner drive mechanism and a pair of fiber-scopes operating as optical lens means of the television camera are connected thereto. One of the fiber-scopes is attached to the upper central portion of the bolt mounting device 32 and the other is attached to a predetermined portion on the peripheral surface of a flange to which the bolt is secured. Although the bolt mounting device 32 supported by the carrier 26 can positioned to a desired position below the control rod drive mechanism 7 by rotating the platform 5, horizontally moving the traveling bogie 21 and raising the carrier 26, when the top end of the bolt mounting device 32 on the carrier 26 approaches the lower end of the control rod drive mechanism 7, this approach is observed through the fiber-scopes by the television camera and projected on the monitor of a remote control operation board. Thus, the position of the bolt mounting device 32 is always remotely observed and precisely and quickly adjusted to the final desired position by controlling the position or angles of the platform 5, the traveling carriage 21 and the bolt mounting device 32. The actual attachment and removal of the control rod drive mechanism 7 will now be described in detail hereinbelow. To remove the mechanism 7, the carriage 54 for conveying the bolt mounting device 32 is firstly moved to the passage for elevating the carrier 26. Then the bolt mounting device 32 suspended from the carriage 54 through pin 52a would be positioned above the carrier 26. Then, the chains 25 are driven to upwardly move the carrier 26, and the bolt mounting device 32 is firmly held by the carrier 26 by engaging the projecting pins 32b with the notches 26a of the carrier 26. The carrier 26 is further slightly moved upwardly to slightly separate the pin 32a from the upper surface of the bolt mounting device 32 and the carriage 54 is then retracted to the predetermined position. After mounting the bolt mounting device 32 on the carrier 26, the platform 5 and the carriage 21 are rotated or moved so that this device 32 will be positioned below the control rod drive mechanism 7 to be removed. The chains 25 are then driven further to raise the carrier 26 to urge the bolt mounting device 32 against the control rod drive mechanism 7 attached to the bottom of the reactor pressure vessel and the bolts which secure this mechanism 7 to the housing 10 are loosened and pulled out by the bolt mounting device 32, while the control rod drive mechanism 7 is being supported by the carrier 26. The carrier, on which the control rod drive mechanism 7 has been supported, is then lowered, and before the upper end of the control rod drive mechanism 7 is completely drawn out from the housing 10, when a portion of this mechanism 7 passes through the position of the holding arm 33 provided with a pair of the holding jaws 38, the arm projects and loosely holds the mechanism 7 to support and guide the same. When the control rod drive mechanism 7 is further drawn out by a predetermined amount, the carrier 26 once stops its movement and the holding arm 33 holds tightly the control rod drive mechanism 7, and thus, the control rod drive mechanism 7 is completely drawn out by again lowering the carrier 26 as shown in FIG. 15. When the carrier 26 is lowered, the arm 33 again holds tightly the control rod drive mechanism 7, which is then rotated to the horizontal position together with the beam 22, and the conveying carriage 8 is moved to a position below the tilted beam 22 to transfer the control rod drive mechanism 7 along the conveying carriage 8 as shown in FIG. 16. Thereafter, the conveying carriage 8 is moved out through the passage 9 towards the inspection chamber. It will be understood that the control rod drive mechanism 7 can be attached to the bottom of the reactor pressure vessel by the reverse operation opposite to that described above in connection with the removal thereof. FIGS. 17 and 18 show another (second) embodiment of apparatus for exchanging the control rod drive mechanism according to this invention, in which the carrier 54 for conveying the bolt mounting device 32 is not used and wheels 101 for conveying this device 32 is disposed on both sides of the upper portion of the device 32 so that the wheels 101 will travel on the rails 53a suspended below the platform 5. In this embodiment, the distance between these rails 53a is determined so that the beam 22, the chains 25 and the carrier 26 can freely move between the rails 53a and the distance between the wheels 101 is also determined to be smaller than the width of the central hollow portion of the platform 5, the distance between the rails 20 and the distance between the both side walls of the traveling carriage 21 are also determined such that the wheels 101 can freely travel between these distances. Although, in this second embodiment, the removal of the control rod drive mechanism 7 can be effected in substantially the same manner as that described in conjunction with the former (first) embodiment, when the carrier 26 is lowered after the arm 33 holds the mechanism 7, the wheels 101 are moved to rest on the rails 53a in response to the lowering of the carrier 26. The bolt mounting device 32 then separates from the carrier 26 and moves along the rails 53a. After this device 32 has been retracted to the predetermined position by suitable drive means, not shown, the carrier 26 is again raised to directly support the control rod drive mechanism 7 and jaws 38 are slightly opened to loosen the control rod drive mechanism 7, whereby it is lowered to the lower-limit position as the carrier 26 lowers. The lowered control rod drive mechanism 7 is then conveyed into the inspection chamber in the same manner as that described in connection with the first embodiment. Further, it will be understood that when the bolt mounting device 32 is supported on the carrier 26, the bolt mounting device 32 carried on the rails 53a is firstly moved by the wheels 101 directly above the carrier 26 and then the carrier 26 is upwardly moved to support the bolt mounting device 32. The movement of the bolt mounting device 32 along the rails 53a may be performed by suitable drive means such as a compact electric motor which can be remotely controlled in a control room. However, in a case where it is impossible to assemble such compact motor into the bolt mounting device 32, the movement thereof may be performed, for example, by a mechanism shown in FIG. 19. Referring to FIG. 19, auxiliary guide members 102 are provided on the outer sides of the rails 53a, respectively, to carry a traveling carriage 105 having wheels 103 and pushing wheels 104 adapted to contact the wheels 101 for conveying the bolt mounting device 32. The carriage 105 is moved by means of chains 105a and 105b connected to the front and rear ends of the carriage 54a. Thus, the bolt mounting device 32 can be moved by driving the wheels 101 by the pushing wheels 104. In this connection, if two pushing carriages 105 were mounted on the both rails 53a, respectively, the bolt mounting device 32 could be precisely moved forwardly or backwardly by selectively driving one of these carriage 105. Further, the pushing carriage 105 may be moved by means of a screw threaded shaft, now shown, in place of the chains 105a and 105b. Although, in FIG. 19, the conveying wheels 101 are mounted on the rails 53a laid on both sides of the bolt mounting device 32, it is also possible to mount only one wheel as shown in FIG. 20 in which case a conveying wheel 107 provided with flange engaging the guide surfaces of a rail 106 is located on one side of the bolt mounting device 32 and a horizontal wheel 109 contacting a guide rail 108 is disposed below the wheel 107 so as to prevent the inclination thereof. FIG. 21 shows another example of the bolt mounting device 32 provided with only one wheel 107 shown in FIG. 20, in which certain portions at one ends of the rails 106 and 108 are constructed to be outwardly swingable about a vertical shaft 110, respectively. In this construction, the removal of the control rod drive mechanism 7 is carried out near the side wall of the working chamber after the bolt mounting device has been removed from the carrier 26 by rotating the bolt mounting device 32 horizontally about the vertical shaft 110 together with the rails 106 and 108 so as not to disturb the operation for removing the control rod drive mechanism 7. FIGS. 22 through 24 show still another (third) embodiment of the control rod drive mechanism exchanging apparatus according to this invention, in which the bolt mounting device 32 is mounted on the carrier 26 by a carriage provided with a rotatable frame 116. According to this embodiment, a rail 111 having I-shape cross section is located at the lower surface of the platform 5 to extent in the direction of traveling of the traveling carriage 21, and a carriage 112 for conveying the bolt mounting device 32 is suspended by an arm member 113 attached to one side of the traveling carriage 21. Within the upper portion of the carriage 112, there are housed traveling wheels 114 disposed on both sides of the vertical member 111a of the rail 111 to roll on the lower member 111b of the rail 111, and guide wheels 115 abutting against the side surfaces of the lower member 111b. One end of the frame 116 is pivotably attached to the vertical shaft 117 of the carriage 112 so that the frame 116 is swingable by about 90.degree. drive means 118, and the frame 116 having the other end provided with a U-shape engaging portion 116a adapted to engage the bolt mounting device 32 as shown in FIG. 24. The U-shape engaging portion 116a is formed so that the opened end thereof will face the beam when it is in the vertical state when the frame 116 is rotated by about 90.degree. to the position shown by dot and dash lines in FIG. 24, and on both side walls of the opening of the U-shape portion 116a there are provided recesses 116b adapted to engage the pins 32a projected from both side walls of the bolt mounting device 32. In a case where the removal of the control rod drive mechanism 7 is necessary, the carrier 26 is firstly lowered to the position having no operational relationship with the bolt mounting device 32 and the frame 116 is then rotated about 90.degree. so as to move the bolt mounting device 32 engaging the U-shape engaging portion 116a to the position above the carrier 26. Under this condition, the carrier 26 is raised to hold the bolt mounting device 32 by causing the engaging pins 32b provided for the bolt mounting device 32 to engage the notches 26a provided for both side ends of the carrier 26. The carrier 26 is then slightly raised till the engaging pins 32a of the bolt mounting device 32 disengaged from the recesses 116b of the frame 116. After the pins 32a of the bolt mounting device 32 have been disengaged, the frame 116 is rotated by about 90.degree. to the original position. Then, the chains 25 are driven to raise the carrier 26 on which the bolt mounting device 32 is supported and to urge the device against the control rod drive mechanism 7 located at the bottom of the reactor pressure vessel. Thus, the bolts connecting the control rod drive mechanism 7 to the pressure vessel are drawn off by the operation of the bolt mounting device 32. After the bolts have been drawn off, the control rod drive mechanism 7 is lowered by lowering the carrier 26 and is held by the holding arm 33 when the control rod drive mechanism 7 is lowered by a predetermined length. The frame 116 is then rotated towards the beam 22 and the carrier 26 is further slightly lowered to cause the recesses 116b of the frame 116 to engage the pins 32a of the bolt mounting device 32 thereby disengaging the engaging pins 32b from the carrier 26, whereby the bolt mounting device 32 is completely held by the frame 116, which is then rotated to the original position shown in FIG. 24 by solid lines. The movement of the control rod drive mechanism 7 to the inspection chamber, after the device 32 has been moved from the passage of movement of the carrier, is carried out in substantially the same manner as that described in connection with the first embodiment of this invention. FIG. 25 shows still further (fourth) embodiment of the control rod drive mechanism exchanging apparatus according to this invention, in which one ends of movable rails 120 adapted to support the carriage 8 for conveying the control rod drive mechanism 7, are pivotably supported by pins 121 at one end of the central hollow portion 5a of the platform 5, and the other ends of the rails 120 are held by a wire-rope 123 driven by a winch 122. A longitudinal hollow space is defined between the rails 120 so that the beam 22 can tilt without contacting the movable rails 120, whereby the bilateral wheels of the carriage 8 can be freely move on the respective rails 120. Further, the rails 120 are provided with a stopping member 120a at one end for stopping the over movement of the carriage 8, and rails 124 are located at the entrance passage 9 so as to align with the rails 120 to smoothly move the carriage 8 when the platform 5 is rotated. In this fourth embodiment, to remove the control rod drive mechanism 7 from the working chamber 1 the control rod drive mechanism 7 drawn out from the housing 10 of the reactor core is firstly moved to the horizontal position by and together with the beam 22. Then, the rails 120 are also tilted about the pin 121 by driving the winch 122 through the wire-rope 123 to the position where the inclination of the rails 120 is equal to that of the rails 124 provided for the entrance passage 9, as shown by dot and dash lines in FIG. 25. In this state, the conveying carriage 8 travels on the rails 124 and 120 and enters from the passage 9 into the position where it abuts against the stopping member 120a. The wire-rope 123 is then wound by the winch 122 to return the rails 120 to the horizontal position together with the conveying carriage 8. Thereafter, the control rod drive mechanism 7 is transferred along the carriage 8 from the beam 22, and the rails 120 are then tilted again to the firstly tilted position by driving the winch 122. The control rod mechanism 7 on the carriage 8 is then conveyed out of the working chamber through the passage 9. According to this fourth embodiment shown in FIG. 25, the control rod drive mechanism conveying carriage 8 freely moves on the rails 120 with ends pivotably supported by the pin 121 attached to the platform 5 and the control rod drive mechanism 7 is easily transferred on the carriage 8 by tilting the rails 120 to the horizontal position from the beam 22 without using jack means which was often used in prior arts. Further, although the fourth embodiment according to this invention is provided with movable rails 120 for conveying carriage 8 disposed on the platform 5, these rails are not always required to be movable, but in this case, it is necessary to secure the rails so that the inclination thereof is the same as that of the rails 124. In such arrangement, the beam 22 will swing between the vertical position of the beam 22 at the time when the control rod drive mechanism 7 is fitted or removed and the horizontally inclined position thereof in parallel with the rails 124 for conveying the carriage 8. Thus, the conveying carriage can smoothly move into and out of the entrance passage 9 by aligning the inclination of the rails 120 in the working chamber 1 with that of the rails 124. Although, in all of the foregoing embodiments, it was described that the control rod drive mechanism 7 is transferred to and from the beam 22 to move the carriage for mounting the mechanism 7 into the relatively narrow working chamber 1 below the reactor pressure vessel, this transfer can be made to the other places as disclosed hereinbelow in conjunction with FIGS. 26 through 29. FIGS. 26 through 29 show such case wherein the control rod drive mechanism 7 is transferred from the first working chamber 1, wherein rails 126 are laid on the floor of the passage 9 at the same level as the rails 20 for the traveling carriage 21 disposed on the platform 5. These rails 126 extend into a second outer working chamber 125 located adjacent the passage 9, and the rails 20 are laid so as to be connected in line with the rails 126 by rotating the platform 5 to a predetermined position as occasion demands. On the floor of the working chamber 125 there are laid rails 127 extending from the lower portion of the rails 126 towards an inspection chamber, not shown, for carrying out periodical inspection of the control rod drive mechanism 7 and on the rails 127 there is mounted a conveying carriage 128 on which jacks 129 and 130 are disposed so that the carriage 128 can travel below the traveling carriage 21 on which the control rod drive mechanism 7 is being supported. According to the arrangement described above, the control rod drive mechanism 7 drawn out from the reactor pressure vessel is firstly tilted to the horizontal position by rocking the beam 22 and the platform 5 is then rotated so as to connect the rails 20 on the platform 5 to the rails 126 in the passage 9 as shown in FIG. 26. Thereafter, the traveling carriage 21 with the control rod drive mechanism 7 mounted thereon is moved on the rails 20 and 126 to convey it out of the first working chamber 1. The carriage 21 conveyed from the working chamber 1 stops at the position where the control rod drive mechanism 7 on the carriage 21 is positioned directly above the conveying carriage 128 as shown in FIG. 27. The jacks 129 and 130 are raised to support the control rod drive mechanism 7. The holding arm 33 which is firmly holding this mechanism 7 is then loosened and the chains 25 are slightly driven, thus transferring the control rod drive mechanism 7 from the carriage 21 onto the carriage 128 as shown in FIG. 28. Then, the jacks 129 and 130 are retracted and the conveying carriage 128 is moved along the rails 127 into the inspection chamber as shown in FIG. 29. It will of course be understood that the control rod drive mechanism 7 can be attached to the reactor pressure vessel by the reverse operations opposite to that described in connection with FIGS. 26 through 29. Further, in a case where the level of the floor of the inspection chamber or a passageway connected thereto is the same as that of the second working chamber 125, the carriage 128 can travel directly into the inspection chamber or the passageway, but in a certain case, these levels of the floors are different from each other according to the structure of a nuclear reactor. Such case will be described hereinbelow in conjunction with FIGS. 30 and 31. Regarding FIGS. 30 and 31, an elevating mechanism for supporting and elevating a table 132 is disposed on the floor of the working chamber 125 and rails 133 on which the conveying carriage 128 travels are laid on the elevating table 132 so that the rails 133 will be connected to rails 135 extending into the inspection chamber through the passageway 134 when the elevating table is raised by the elevating mechanism 131. When the traveling carriage 21 moves into the working chamber 125, the elevating mechanism 131 operates to raise the elevating table 132 together with the conveying carriage 128, whereby the control rod drive mechanism 7 is transferred from the traveling carriage 21 to the conveying carriage 128. After the control rod drive mechanism 7 has been transferred, the elevating table 132 is once lowered and the traveling carriage 21 is moved back into the working chamber 1. Then the elevating table is again raised to the position where the rails 133 are connected in line with the rails 135 laid in the passage way 134 to outwardly move the conveying carriage 128 together with the control rod drive mechanism 7 as shown in FIG. 31. FIG. 32 shows another example for moving the conveying carriage 128 into the working chamber 125, in which the rails 127 are laid on a track 136 pivotably secured by suitable means to the side wall 125a of the working chamber 125 opposing the wall provided with the passage 134. In this example, the rails 127 are connected in line with the rails 135 by upwardly tilting the track 135 to outwardly move the carriage 128 together with the control rod drive mechanism 7. FIG. 33 shows a case where one ends of the rails 127 are pivotably secured to the front end of the track 136, and in this case, the rails 127 are upwardly rotated about the front end of the track 136 to a horizontal position parallel with the rails 135, thus smoothly and horizontally moving the carriage 128 together with the control rod drive mechanism 7. Although in the foregoing examples conveying carriage 128 provided with two jacks 128 and 129 was shown, it is possible, as shown in FIG. 34, to support the upper portion of the control rod drive mechanism 7 by the jack 129 by utilizing the characteristic feature of the swingable beam 22, that is, the lower portion of the control rod drive mechanism 7 is moved on the carriage 128 by utilizing this swingable feature of the beam 22. Furthermore, with the examples provided with the second working chamber 125, the operators are not required to work in the first working chamber 1 where they may be exposed to radiations and almost all jobs, such as loading of the control rod drive mechanism 7 on the conveying carriage, can be carried out in the second outer working chamber 125, thus substantially eliminating the danger of exposing the workers to radiations. Moreover, since apparatus and devices, such as a traveling carriage and a beam, for use in the exchange of the control rod drive mechanism could be accommodated in the second working chamber 125 when they are not used, these devices are also hardly exposed to radiations, and the inspection and the maintenance thereof can be readily and safely carried out in this second working chamber. In an ordinary boiling water reactor, the distance from the lower end of the stud bolt 11 to the floor of the working chamber 1 is predetermined to a minimum which is slightly longer than the entire length of the control rod drive mechanism in view of the cost of constructing a nuclear reactor plant. For this reason, in order to completely draw out the control rod drive mechanism in the vertical direction, it is necessary to remove the bolt mounting device 32 as described hereinbefore. Therefore, it is required to move the carriage for conveying the bolt mounting device 32 each time when this device 32 is removed and in order to properly maintain the positional relationship between the bolt mounting device 32 and the beam 22, it is necessary to perform troublesome adjustment. However, this troublesome adjustment can eliminated by always connecting the bolt mounting device 32 conveying carriage 54 to the beam 22 when the beam 22 assumes the vertical position. This arrangement will be described with reference to FIGS. 35 through 37. In FIGS. 35 through 37, a carriage 140 for conveying the bolt mounting device 32 is provided with wheels 141 near the upper portion of the frame 140a of the carriage 140 to be movable along rails 53 disposed below the platform 5. As shown in FIG. 36, the frame 140a has a U-shaped cross-section and a seat member 142 having projections 142a is attached to the inside surface of the frame 140a opposing the vertical beam 22. The seat member 142 engages a latch member 143 provided on the side surface of the bolt mounting device 32 so as to hold the bolt mounting device 32 by the frame 140a. A supporting plate 144 contacting the side surface of the bolt mounting device 32 is attached to the frame 140a at a portion beneath the seat member 142 thereby maintaining the bolt mounting device 32 in upright state (FIG. 37). Air cylinder-piston assemblies 145 are attached to both side surfaces of the frame 140a and coupling members 146 are secured to the piston rods 145a of the assemblies 145, respectively. These coupling members 146 project to oppose each other. The frame 140a is further provided with U-shaped elongated covers 147 which cover the air cylinder-piston assemblies 145 and each of these covers 147 also covers the base of the coupling members 146, thereby permitting the coupling members to reciprocate in the direction parallel with the piston rod 145a but not permitting its rotation thereabout. Pedestals 148 are attached to both sides of the beam 22. One ends of connecting links 150 are connected by pins 149 to the pedestals 148, respectively, and recesses 150a are formed on the outer sides of the other ends of the link members 150 to receive coupling members. A pedestal 151 is attached to the inside of the beam 22 to pivotably support the bases of two air cylinder-piston assemblies 152. The front ends of the piston rods 152a of the air cylinder-piston assemblies 152 are connected to the corresponding link members 150. According to this arrangement, upon operation of respective air cylinder-piston assemblies 152, the recesses 150a of connection link members 150 engage or disengage the front ends of the coupling member 146. The size of each air cylinder-piston assembly 145 is predetermined so that the bolt mounting device 32 carried by the carriage 140 will be positioned on the elevating passage of the carrier 26 when the piston rod 145a is mostly contracted, i.e., when the frame 140a most closely approaches the beam 22 and so that the carrier 26 supporting the control rod drive mechanism 7 can be freely elevated when the piston rod 145a is mostly protruded, i.e., when the frame 140a is most remote from the beam 22. When it is desired to remove the control rod drive mechanism 7, the conveying carriage 140 is connected to the beam 22 by engaging the member 146 with the link members 150. Under these conditions, the bolt mounting device 32 approaches most closely the beam 22 by contracting the air cylinder-piston assemblies 145 and the bolt mounting device 32 is moved to a position below the desired control rod drive mechanism 7 to be removed in combination of the rotatary movement of the platform 5 with the linear movement of the traveling carriage 21 described hereinbefore. After the position of the bolt mounting device 32 has been adjusted, the carrier 26 is raised to support and transfer the bolt mounting device 32 carried on the carriage 140 and the bolts which connect the control rod drive mechanism 7 to the housing 10 are removed by the operation of the bolt mounting device 32. After the bolts have been removed, when the carrier 26 is lowered to draw out the control rod drive mechanism 7, the holding arm 33 holds the mechanism 7. As the carrier 26 is lowered further latch member 143 of the bolt mounting device 32 engages the seal member 142 of the conveying carriage 140, whereby the bolt mounting device 32 is transferred onto the carriage 140. Upon completion of the operations described above, when the air cylinder-piston assemblies 150 operate to move the bolt mounting device 32 in a direction remote from the beam 22, due to the connection of the beam 22 with the front end of the piston rods 145a through the engagement of the coupling members 146 with the link members 150, the carriage 140 is moved away from the beam 22. The carrier 26 is again raised to receive the control rod drive mechanism 7 to draw out it, and the platform 5 and the traveling carriage 21 are then moved to positions suitable for rotating the beam 22 from the vertical state to the horizontal state. When the beam 22 has been moved to its tiltable position, the air cylinder-piston assemblies 152 are operated to disengage the link members 150 from the coupling members 146, thus enabling the beam 22 to rotate to the horizontal position. Thereafter, the control rod drive mechanism 7 is transferred onto the conveying carriage 8 which is conveyed into the inspection chamber in a manner described hereinbefore. In this example, since the bolt mounting device conveying carriage is connected to the beam 22 and moved together with the traveling carriage 21, the positional adjustment of the bolt mounting device conveying carriage with respect to the beam 22 can be eliminated each time when the control rod drive mechanism is exchanged, thereby reducing the working time and job of the operators. In the aforementioned embodiments, although the control rod drive mechanism 7 is once held by the holding arm 33 during the lowering of the control rod drive mechanism 7, it may be possible to temporarily hold the control rod drive mechanism by the bolt mounting device conveying carriage. This example will be described in detail hereunder in conjunction with FIGS. 28 through 40, in which a carriage 160 for conveying the bolt mounting device 32 is movably mounted on the rails 20 laid on the platform 5 for the traveling carriage 21. The conveying carriage 160 is provided on its both sides with connection fingers 163 to be rotatable about pins 162 which are operated by means of air cylinder-piston assemblies 161. The conveying carriage 160 and the traveling carriage 21 are connected with each other by the engagement of the fingers 163 and pins 164 projected from the both sides of the traveling carriage 21. The bolt mounting device conveying carriage 160 is further provided with a frame 160a (FIG. 39). Rails 165 and 166 with a predetermined spacing therebetween are laid on the upper and lower surfaces of the frame 160a. A first supporting member 168 is carried by the upper rails 165 through wheels 167 and the first supporting member 168 can be moved along the rails 165 so as to travel between a position where the control rod drive mechanism 7 is supported and a position not to disturb the elevation of the carrier 26. A second supporting member 170 is carried by the lower rails 166 through wheels 169 so as to travel between a position where the bolt mounting device 32 is supported and a position not to disturb the elevation of the carrier 26. These supporting members 168 and 170 are actuated by air cylinder-piston assemblies 171 and 172, respectively. In this arrangement, when the bolts which connect the control rod drive mechanism 7 to the housing 10 are to be loosened, the second supporting member is firstly advanced to move the bolt mounting device 32 to a position in the passage of the carrier 26. Then, the carrier 26 is raised to transfer the bolt mounting device 32 to its operating position in the same manner as described before. When the control rod drive mechanism 7 is drawn out by a predetermined length, the first supporting member 168 is advanced to support the control rod drive mechanism 7. Thereafter, the bolt mounting device 32 is transferred onto the second support member 170 by lowering the carrier 26. The bolt mounting device 32 is then returned to the retracted position. The carrier 26 is again raised to support the control rod drive mechanism 7, and the first supporting member 168 is retracted to the position not to disturb the movement of the carrier 26. Thereafter, the control rod drive mechanism will be completely drawn out and conveyed into the inspection chamber in the same manner as described hereinbefore. Further, it should be noted that when the beam 22 is tilted to its horizontal position, the connection finger 163 is rotated counter-clockwisely as viewed in FIG. 37 by the air cylinder-piston assembly 161 to disengage the finger 163 from the pin 164 so as to move the conveying carriage 160 to the position not to disturb the tilting movement of the beam 22. According to the example described just above, since the control rod drive mechanism 7 is not held and temporarily suspended by the holding arm 33, but supported by the supporting member, the control rod drive mechanism 7 is frimly supported. Furthermore, in this example, since the bolt mounting device conveying carriage travels along the rails for the traveling carriage, the bolt mounting device can be operated to a relatively high position so that exchange of bolts by the spanners can be readily carried out through the passage 9 provided through the side wall of the working chamber 1. FIG. 41 shows another example of a multi-shaft bolt clamping device of the bolt mounting device of this invention, in which the bolt mounting device 32 is provided with four spanners 66a, 66b, 66c and 66d and a differencial gearing 65 for driving these spanners. In this example, the output shaft 63a is provided with an arm 71' to which pinions 200 and 201 such as shown in FIG. 7 are mounted, and these pinions are adapted to mesh with internal gears 202a, and 203a so as to rotate discs 202 and 203 for supporting the internal gears 202 and 203, respectively. Thus, the arm 71' is rotated integral with the supporting disc 202 and an arm 71" is also rotated integral with the supporting disc 203 thereby rotating pinions 74' and 75', respectively. According to this gearing arrangement, the spanners 66a through 66d clamp all bolts firmly with uniform torque when the differential gearing 65 is driven. FIGS. 42 and 43 show another example wherein eight bolts are clamped all at once. In FIG. 43, a pair of gears 76a and 76b are meshed with the external gear 70 and rotary shafts 205 for the gears 76a and 75b are provided with splines 204, respectively, to which movable engaging portions 206a of clutches 206 are fitted so that the clutches 206 can slide vertically and rotate integrally with the rotary shafts 205. The movable engaging portions 206a are connected with each other through a swingable rod 208 having fork-shape ends. The rod 209 is connected to each engaging portion through bearings 207 and pins 209 of the rod 208. The rod is swingable about a pin 210. Stationary engaging portions 206b adapted to engage the movable engaging portions 206a of the clutches 206 are loosely mounted on the rotary shafts 205. Spanners 66a' and 66a" are fixedly mounted on the square shafts 206b' of the stationary engaging portions 206b through springs 211, respectively. Accordingly, when the examples shown in FIGS. 6 and 42 are combined, it should be understood that four bolts are clamped all at once by mere design change of the spanner 66a to the spanners 66a' and 66a", and when examples shown in FIGS. 41 and 42 are combined, it should also be understood that eight bolts can be clamped all at once. FIG. 44 shows another example of FIG. 6, in which a differential gearing 65 comprising bevel gears is utilized in the example shown in FIG. 44 in place of differential gearing 65 comprising spur gears shown in FIG. 6. One example of the multi-shaft bolt clamping device of this invention including a bolt loosening device will be described hereunder with reference to FIGS. 45 and 46. A drive disc 212 provided with a notch 212a is mounted on the output shaft 63a of the reduction gear 63, and the arm 71 is also loosely mounted thereon close to the drive shaft 212. To this arm 71 are embedded bases of the pins 72 and 73 on which the pinions 74 and 75 are mounted, respectively, and in addition to the engagement of these pinions 74 and 75, the pinion 74 meshes with the internal gear 69a and the pinion 75 meshes with internal gear 70a, respectively. A pin shaft 213 is loosely fitted to a portion of the arm 71. A swingable lock rod 214 and a pair of lock pawls 215a and 215b are firmly mounted on the pin shaft 213 as shown in FIG. 44, and a spring 216 is attached between one end of the lock rod 214 and the stepped portion of the arm 71 to cause the lock pawls 215a and 215b to engage the bottom lands of the gear teeth of the internal gears 69 and 70, respectively, due to the action of the spring 216. The other end 214a of the lock rod 214 extends into and engages with the notch 212a of the disc 212. The arm 71 is further provided with a projection 217 at a suitable position on the passage of movement of the swingable lock rod 214. According to this arrangement, when the drive disc 212 rotates clockwisely to push the projection 217, the arm 71 is rotated about the shaft 63a. Conversely, when the drive disc 212 rotates counter-clockwisely to push the end 214a of the rod 214, the rod 214 is rotated clockwisely about the pin 213 against the force of the spring 216 thereby disengaging the lock pawls 215a and 215b from the internal gears 69a and 70a. Then, the end 214a of the lock rod 214 pushes and rotates the projection 217, thus rotating the arm 71 about the output shaft 63a in the direction opposite to the direction described before. Further, the pin shaft 213 is held by an arm piece 218 loosely fitted on the output shaft 63a. Now, when the two bolts which connect the control rod mechanism 7 to the housing 10 are to be loosened, the spanners 66a and 66b are engaged with the corresponding bolts. Under these conditions, when the electric motor 61 rotates, the differential gearing 65 is driven by the rotation of the output shaft 63a through the torque limit member 62 and the reduction gear 63. In other words, when the output shaft 63a is clockwisely rotated, the drive disc 212 pushes the projection 217 thereby rotating the arm 71 about the shaft 63a. Then, the lock pawls 215a and 215b firmly engage the bottom lands of the gear teeth of the internal gears 69a and 70a, respectively, so that the internal gears 69a and 70a are rotated by the pinions 74 and 75. At this time, even when the meshing of gears 69a, 70a with pinions 74 and 75 is not synchronous, the both gears can rotate synchronously by the locking action of the lock pawls 215a and 215b. However, when both lock pawls 215a and 215b are firstly completely engage with the internal gears 69a and 70a and the output shaft 63a is driven to clockwise rotate the arm 71 through the engagement with the projection 217, the internal gears 69a and 70a are clockwisely driven by the same torque with each other. At this time, when the internal gear 69a rotates to loosen the bolt engaged by the spanner 66a while clamping the other spanner 66b, the pinion 74 is rotated counter-clockwisely by the differencial gearing mechanism of the pinions 74 and 75 while stopping the other internal gear 70a and while the pinion 75 is rotating clockwisely, thus clockwisely rotating the internal gear 69a. However, when the arm 71 is slightly rotated clockwisely by the rotation of this pinion 75, the lock pawl 215b firmly engages the internal gear 70a, thereby imparting a strong driving force to the internal gear 70a. Thus, both internal gears 69a and 70a are rotated to loosen the corresponding bolts and then, the amounts of rotation of both gears are maintained to be equal, thus, in such case, loosening the bolts by the internal gears 69a and 70a through the spanners 66a and 65b. In the example described directly above, the clamping of two bolts are carried out by the following manner. When the disc 212 is rotated counter-clockwisely by the counter-clockwise rotation of the output shaft 63a, the wall of the notch 212a formed on the disc 212 pushes the swingable lock rod 214 and the rod 214 is then rotated clockwisely about the pin shaft 213 against the force of the spring 216. The rotation of this rod 214 disengages the lock pawls 215a and 215b from the internal gears 69a and 70a, respectively. When the rod 214 collides against the projection 217, the arm 71 provided with the pinions 74 and 75 is rotated, thus clamping all bolts at the same time. Finally, FIG. 47 shows another example of the automatic multi-shaft bolt clamping device of this invention including a bolt loosening device and this example is a modification of the example provided with the bevel gear-type differential gearing shown in FIG. 44. In this example, a drive disc 212 provided with a pair of notches 212a is firmly mounted on the output shaft 63a and a pair of cam members 212b is provided on the outer periphery of the disc 212. An arm 71 provided with pinions 74 and 75 is loosely mounted on the output shaft 63a and projections 217 are formed on the intermediate portions of the projections of the arm 71 so as to engage the notches 212a, respectively. Furthermore, radial guide grooves 219 are formed on the arms near the projections 217 and lock pawls 215a and 215b are slidably fitted into the guide grooves 219 so that the lock pawls will engage the bottom lands of the gear teeth of the internal gears 69a and 70a, respectively, by the forces of springs 216. The lock pawls 215a and 215b include rollers 220 so as to abut against the cam members, respectively. According to this arrangement, when the output shaft 63a is clockwisely rotated, the lock pawls 215a and 215b are disengaged from the guide grooves 219 by the operation of the cam members 212b integrally formed with the disc 212 through the rollers 220, thus enabling the pinions 74 and 75 to be freely rotatable. On the other hand, when the output shaft 63a is counterclockwisely rotated, the cam portions 212b lock and temporarily fix the lock pawls 215a and 215b to the internal gears 69a and 70a through the rollers 220 by forces of the springs 216. As above described the loosening and clamping of the bolts can be carried out by the rotation of the output shaft 63a. Consequently, as is clarly understood from the foregoing descriptions, according to this invention, since there is provided apparatus for exchanging control rod drive mechanisms comprising a beam 22 tiltably mounted on the traveling carriage disposed below the reactor pressure vessel, a carrier 26 movable along the edge of the beam, and a conveying mechanism for mounting the bolt mounting device on the carrier, it became possible to exchange the control rod drive mechanism purely mechanically and to eliminate the jobs of the workers in the working chamber likely to be exposed to relatively high radiations, thus assuring the safeness of the workers and moreover, largely eliminating the works of the workers.
047755105	abstract	A hollow flow deflector (10) for use in a nuclear reactor fuel assembly having spaced grids of orthogonal strips (16, 18) mounted for defining square matrices of aligned and supported cylindrical fuel elements (12, 14). The deflector has a central cylindrical opening (20), an upstream end portion (22), a downstream end portion (24) and an intermediate transition portion (26) joining the end portions. The hollow flow deflector (10) has a plurality of concave flow channels (30) regularly spaced about the periphery of the body in its downstream end portion. The flow channels (30) have their inlet portion defined in the transition portion (26) of the body (10).
047284862	abstract	A pressure control system for a pressurized water nuclear reactor and method for quickly closing the valves associated with the pressurizer thereof has a temperature detection device on the loop seal of each valve and a valve responsive thereto to change water to the loop seal upon a temperature rise therein and stop the flow of water to the loop seal upon a temperature drop therein. The rapid formation of water seals in the loop seals for the valves protects the valve seats from wear and degradation and prolongs the life thereof.
	summary
	claims	1. A charged particle beam applying apparatus including a charged particle gun that generates and accelerates a charged particle beam, a lens that converges the charged particle beam, a deflector that controls a traveling direction of the charged particle beam, a stage on which a test sample is mounted, a vacuum pump that keeps a path of the charged particle beam in a substantially vacuum state, the apparatus comprising:a crossover forming lens for causing one of a crossover of the charged particle beam emitted from the charged particle gun and an intermediate image of the crossover to be formed;a shielding plate provided with an end face for regulating an image forming plate of the crossover forming lens;an aligner for scanning the shielding plate with the charged particle beam; andmeans for measuring an amount of the charged particle beam shielded by the shielding plate. 2. The charged particle beam applying apparatus according to claim 1,wherein the shielding plate is movable between a beam axis and an outside of the beam axis without impairing the near vacuum state of the path of the charged particle beam. 3. The charged particle beam applying apparatus according to claim 1,wherein a member forming the end face of the shielding plate is conductive and non-magnetic, is formed of a material with a melting point of 1000 or more degrees Celsius, and has a thickness of 50 or more microns. 4. The charged particle beam applying apparatus according to claim 1,wherein the shielding plate is movable in upstream and downstream directions with respect to the traveling direction of the charged particle beam. 5. The charged particle beam applying apparatus according to claim 1,wherein the shielding plate is provided with a plurality of end faces, and the plurality of end faces are capable of being placed at different points on the beam axis. 6. The charged particle beam applying apparatus according to claim 1,wherein the crossover forming lens is formed of a plurality of lenses, thereby acting as a zoom lens for varying a magnification without changing an imaging plane. 7. The charged particle beam applying apparatus according to claim 1, further comprising an aperture through which the charged particle beam spread from the intermediate image of the crossover is divided into a plurality of charged particle beams, and a plurality of lenses that individually converges the plurality of charged particle beams,wherein the shielding plate is provided between the charged particle gun and the aperture. 8. The charged particle beam applying apparatus according to claim 7, further comprising a condenser lens that shapes the charged particle beam spread from the intermediate image of the crossover so as to be approximately parallel,wherein the shielding plate is capable of being placed on a front focal plane of the condenser lens. 9. The charged particle beam applying apparatus according to claim 1, further comprising a mask that determines a shape of the charged particle beam with which the test sample is irradiated, and a lens that forms an image of the mask on the test sample at a desired magnification,wherein the shielding plate is provided between the charged particle gun and the mask. 10. A charged particle beam applying method in a charged particle beam applying apparatus including a charged particle gun that generates and accelerates a charged particle beam, an aligner that controls a traveling direction of the charged particle beam emitted from the charged particle gun, a forming lens that converges the charged particle beam emitted from the charged particle gun, and a shielding plate provided with an end face, the method comprising:a first step of inserting the shielding plate onto a path of the charged electron beam;a second step of scanning the end face of the shielding plate with the charged particle beam by using the aligner and simultaneously detecting a signal of the charged particle beam shielded by the shielding plate;a third step of obtaining a shape of the charged particle beam on the shielding plate based on the signal obtained in the second step;a fourth step of adjusting parameters that determine a focal length of the forming lens so that the shape of the charged particle beam obtained in the third step approaches a desired shape;a fifth step of recording the parameters obtained in the fourth step on a recording device incorporated in the charged particle beam applying apparatus; anda sixth step of removing the shielding plate from the path of the charged particle beam. 11. A charged particle beam applying method in a charged particle beam applying apparatus including a charged particle gun for generating and accelerating a charged particle beam, a stage on which a test sample is mounted, a lens that causes an intermediate image of a crossover formed by the charged particle gun to be formed, a condenser lens that shapes the charged particle beam spread from the intermediate image of the crossover so as to be approximately parallel, an aperture through which the charged particle beam spread from the intermediate image of the crossover is divided into a plurality of charged particle beams, a lens array in which a plurality of lenses for individually converging the plurality of charged particle beams are arranged, a blanker array for individually controlling whether the charged particle beams reach onto the test sample, an aperture plate having apertures with an approximately same interval as an array interval of the lens array, a deflector that scans the aperture plate with the plurality of charged particle beams, and detecting means that measures an amount of charged particle beams passing through the aperture plate, the method comprising the steps:scanning the aperture plate with at least four specific beams selected by the blanker array to regularly measure an aperture image of the aperture plate; andcomparing a measurement result with an aperture image immediately after adjustment to determine when to adjust the condenser lens.
041522079	abstract	A lateral restraint and control system for a nuclear reactor core adaptable to provide an inherent decrease of core reactivity in response to abnormally high reactor coolant fluid temperatures. An electromagnet is associated with structure for radially compressing the core during normal reactor conditions. A portion of the structures forming a magnetic circuit are composed of ferromagnetic material having a curie temperature corresponding to a selected coolant fluid temperature. Upon a selected signal, or inherently upon a preselected rise in coolant temperature, the magnetic force is decreased a given amount sufficient to relieve the compression force so as to allow core radial expansion. The expanded core configuration provides a decreased reactivity, tending to shut down the nuclear reaction.
	abstract	A method includes dividing a semiconductor wafer into a plurality of dies areas, generating a map of the semiconductor wafer, scanning each of the plurality of die areas of the semiconductor wafer with a laser, and adjusting a parameter of the laser during the scanning based on a value of the die areas identified by the map of the semiconductor wafer. The map characterizing the die areas based on a first measurement of each individual die area.
048274933	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to a radiographic source and an associated method of making a radiographic source. The radiographic source and the associated method of making thereof are described herein in connection with the manufacture of a cobalt-60 radiographic source. The present invention also relates to a new technique for the accurate measurement of focal spot size for in particular cobalt-60 radiographic sources. 2. Background Discussion Radiographic sources are presently known and are constructed with the use of such radioactive materials as cobalt-60 and iridium-192. A cobalt-60 radiographic source presently manufactured by the assignee herein is constructed of inner and outer stainless steel capsules with the inner capsule containing a plurality of cobalt-60 pellets; the number of cobalt-60 pellets being the function of the source size. The inner capsule is seal welded by a plug or cover also of stainless steel. In the past attempts have been made to compact the cobalt-60 pellets. However, the compaction has not been totally effective. The techniques used to date have caused deformation of the capsule to the extent that the inner capsule could not be inserted into the outer capsule. Accordingly, one object of the present invention is to provide an improved method of making a radiographic source in which the source radioactive material is effectively compacted so as to provide an actual effective density as high as 90% of the density of the cobalt metal. It is to be noted that this improved radiographic material compression provides a considerably higher activity in a smaller focal spot size, resulting in substantial money savings in radiography exposure time alone. With the presently employed stainless steel inner capsule there has always been some inherent factors that yielded uncertainty over the exact focal spot size provided. There was a statistical error relating to the cobalt pellet orientation at the edges of the focal spot (edge effects). There is also distortion of the focal spot due to ineffective compression. There was uncertainty over void volume due to the ineffective compression. There was also a statistical error from the cobalt-60 specific activity which is measured before encapsulation. While the contribution from each of these factors may be only a few percent, they are additive when calculating the overall uncertainty. The smallest focal spot size has been in demand by the industry in general for many years. However, actual verification of focal spot size has been virtually impossible due to the fact that cobalt and steel have very similar atomic numbers (cobalt=27, steel=26) and a very similar density (cobalt=8.9 gm/cc, steel=7.9 gm/cc ). This means that it is extremely difficult to separate these materials by x-ray analysis. Accordingly, it is another object of the present invention to provide an improved radiography source and associated method of manufacture with the inner capsule construction of a material that enables adequate film contrast by x-ray radiography between the inner capsule and the radioactive material. A further object of the present invention is to provide an improved technique for in particular accurately measuring the focal spot size for a radiographic source and for in particular a cobalt-60 radiographic source. Still another object of the present invention is to provide an improved apparatus for compacting radioactive pellets and for particularly compacting cobalt-60 pellets in a capsule. Still a further object of the present invention is to provide the improved apparatus as recited in the preceding object and in which the capsule is constructed of a material that has a sufficiently different atomic number in comparison to the radioactive material so that adequate film contrast by x-ray radiography can be achieve while at the same time constructing the capsule of a material with sufficient tensile strength so as to assist in preventing deformation thereof during the compacting step. SUMMARY OF THE INVENTION To accomplish the foregoing and other objects, features and advantages of the invention, there is provided a method of making a radiography source of a radioactive material, described herein in a preferred embodiment in connection with the manufacture of a cobalt-60 radiographic source. This method comprises the steps of providing a plurality of radioactive pellets and furthermore providing an open capsule of a rigid metal having sufficient tensile strength to resist substantial deformation under pressure and selected from a group including elements of the periodic table displaced in density on the amount at least on the order of 2.0 gm/cc in comparison to the density of the radioactive pellet material. Generally speaking, this difference in density may also be expressed in terms of atomic number in which case the capsule is formed of an element displaced in atomic number by at least two from the atomic number of the radioactive pellet material. The radioactive pellets are disposed in the capsule and are compacted to reduce the source of focal spot size. A rigid metal plug is inserted in the open end of the capsule and the capsule is then welded closed. The compacting is provided by means of a ram that is dimensioned for close tolerance fit in the capsule. The pellets are compacted by inserting the ram into the capsule and applying a predetermined pressure to the ram. The pressure that is applied is a direct function of the area being compacted. In connection with this compacting step, there is also provided a die in which the capsule is disposed. The capsule is disposed in the die, which is preferably a split die, in a manner to hold the capsule so as to prevent any substantial deformation of the capsule due to pellet compaction. In accordance with the invention, the capsule, in a preferred embodiment, is constructed of titanium which has an atomic number of 22 in comparison to the cobalt atomic number of 27, and also has a density of 4.5 gm/cc in comparison to the aforementioned density of cobalt which is 8.9 gm/cc. In association with the pellets, there may also be provided one or more inserts of the same material as the capsule material. These inserts are disposed in the capsule after compacting the pellets and before inserting the plug. In accordance with a further feature of the present invention there is provided a radiography source of a radioactive material which in the further embodiment is radioactive cobalt-60. This source comprises a plurality of radioactive pellets disposed in an open capsule. The capsule is of a rigid metal having sufficient tensile strength to resist substantial deformation under pressure and selected from a group including elements of the periodic table displaced in atomic number by at least two from the atomic number of the radioactive pellet material. The pellets are disposed in the capsule and compacted therein to reduce the source focal spot size. A plug is disposed in the open capsule and sealed therewith. The aforementioned capsule is then contained in an outer capsule that may be constructed of stainless steel. In accordance with the invention, the preferred construction of the inner capsule is of titanium as this material has an atomic number displaced by five from that of the radioactive material in the case of radioactive cobalt-60. In accordance with still a further aspect of the present invention there is provided an improved press apparatus for providing pellet compaction and employed in the manufacture of a radiography source in which the source is of a radioactive material such as the aforementioned cobalt-60. The source includes a plurality of radioactive pellets contained in a capsule of a rigid metal having sufficient tensile strength to resist substantial deformation under pressure and selected from a group including elements of the periodic table displaced in atomic number by at least two from the atomic number of the radioactive pellet material. The press apparatus of the invention includes a ram means dimensioned from a close tolerance fit in the capsule and means for applying pressure for contacting the ram means, once positioned in the capsule. This latter means includes means for applying a predetemrined pressure to the ram means of an order of magnitude that is a direct function of the number of pellets to be compacted. The ram means preferably fits within the capsule with a close tolerance fit. The press means described herein includes a housing for supporting a press member. The press member preferably has a diameter greater than the diameter of the ram means and is supported so that the ram means progresses into the capsule during compaction without any cocking between the ram and the capsule. In this connection, there is provided a die having a hole therein for receiving the capsule. The die is preferably a split die comprised of separate die parts that can be opened and closed. The die parts are supported for sliding movement along a track from an initial position at which the die parts are opened for receipt of the capsule to a compacting position at which the die parts are locked closed during contact of the press member with the ram. The die, as well as the selected tensile strength of the capsule material together prevent any substantial deformation, particularly radial deformation of the capsule. The ram is preferably of cylindrical shape adapted to be disposed to about one-half its length into the capsule before pellet compaction and about three-fourths its length into the capsule after pellet compaction. The ram preferably has right angle corners at its bottom where the ram contacts the pellets.
	abstract	Modular anode assemblies are used in electrolytic oxide reduction systems for scalable reduced metal production via electrolysis. Assemblies include a channel frame connected to several anode rods extending into an electrolyte. An electrical system powers the rods while being insulated from the channel frame. A cooling system removes heat from anode rods and the electrical system. An anode guard attaches to the channel frame to prevent accidental electrocution or damage during handling or repositioning. Each anode rod may be divided into upper and lower sections to permit easy repair and swapping out of lower sections. The modular assemblies may have standardized components to permit placement at multiple points within a reducing system. Example methods may operate an electrolytic oxide reduction system by positioning the modular anode assemblies in the reduction system and applying electrical power to the plurality of anode assemblies.
	abstract	A control mechanism for a high-voltage generator for supplying voltage and current to an electronic radiation source in high-temperature environments is provided, the control mechanism including at least one voltage feedback loop for monitoring the output of the generator; at least one environmental temperature monitor; a control bus; and at least one control processor. A method of controlling a high-voltage generator that powers an electronic radiation source in high-temperature environments is also provided, the method including at least: measuring the output voltage of the generator; measuring the temperature within the generator's environment, using a control mechanism to modify a driving frequency, and using a control mechanism to modify a driving pulse-train, such that changes in properties of the electronic components of the generator as a result of changes in environmental temperature are characterized and the generator's driving signals modified to maintain optimally efficient input parameters for a specific environmental temperature.
046648810	claims	1. A cladding tube for containing nuclear fuel material, wherein said cladding tube comprises: an outer tubular member; an inner tubular member; said inner tubular member located inside of said outer tubular member; the outer circumferential surface of said inner tubular member bonded to the inner circumferential surface of said outer tubular member over essentially the entire outer circumferential surface of said inner tubular member; said outer tubular member composed of a first alloy selected from the group of zirconium alloys consisting of Zircaloy-2 and Zircaloy-4 type alloys; and Zr-Nb alloys containing about 1.0 to 3.0 w/o Nb, said inner tubular member composed of a second alloy consisting essentially of: about 0.1 to 0.6 w/o tin; about 0.07 to 0.24 w/o iron; about 0.05 to 0.15 w/o chromium; up to about 0.05 w/o nickel; the balance of said second alloy consisting essentially of zirconium and incidental impurities; and wherein oxygen comprises less than about 350 ppm of said alloy; and said inner tubular member having a fully recrystallized grain structure and a wall thickness of at least about 0.003 inch. about 0.18 to 0.24 w/o iron; about 0.07 to 0.13 w/o chromium; and less than about 0.007 w/o nickel. about 0.07 to 0.20 w/o iron; and about 0.03 to 0.05 w/o nickel. obtaining an intermediate size composite cladding tube; then surface beta treating an outer layer of said outer tubular member; then cold working said intermediate size composite cladding tube in one step to substantially final size; and then annealing said composite cladding tube at a temperature below about 600.degree. C. to produce a fine fully recrystallized grain size in said inner tubular member. an elongate composite cladding container; a nuclear fuel material sealed within said composite cladding container; said elongate composite cladding container having: said substantially cylindrically shaped pellets are stacked within said elongate composite cladding container forming a plenum space near one end of said elongate composite cladding container and wherein a spring means is located in said plenum exerting pressure on one end of said cylindrically shaped pellets; and said plenum also containing said pressurized inert gas. 2. The composite cladding tube according to claim 1 wherein the total amount of said incidental impurities is less than about 1000 ppm. 3. The composite cladding tube according to claim 1 wherein said second alloy contains: 4. The composite cladding tube according to claim 1 wherein said second alloy contains: 5. The composite cladding tube according to claim 1 wherein said second alloy contains 0.2 to 0.6 w/o tin. 6. The composite cladding tube according to claim 3 wherein said second alloy contains 0.2 to 0.6 w/o tin. 7. The composite cladding tube according to claim 4 wherein said second alloy contains 0.2 to 0.6 w/o tin. 8. The composite cladding tube according to claim 6 wherein said first alloy is Zircaloy-4. 9. The composite cladding tube according to claim 7 wherein said first alloy is Zircaloy-2. 10. The composite cladding tube in accordance with claim 1 produced by a process comprising the steps of: 11. A water reactor nuclear fuel element comprising: 12. The fuel element according to claim 11 wherein 13. The cladding tube according to claim 1 wherein said incidental impurities are limited to the following in weight percent: 14. The cladding tube according to claim 8 wherein said incidental impurities are limited to the following in weight percent: 15. The cladding tube according to claim 9 wherein said incidental impurities are limited to the following in weight percent: 16. The water reactor nuclear fuel element according to claim 11 wherein said first alloy is Zircaloy-2. 17. The water reactor nuclear fuel element according to claim 11 wherein said first alloy is Zircaloy-4. 18. The water reactor nuclear fuel element according to claim 11 wherein said incidental impurities are limited to the following: 19. The cladding tube according to claim 1 wherein said second alloy contains 0.3 to 0.5 w/o tin. 20. The water reactor nuclear fuel element according to claim 11 wherein said second alloy contains 0.3 to 0.5 w/o tin. 21. The cladding tube according to claim 1 wherein said bond between the outer circumferential surface of said inner tubular member and the inner circumferential surface of said outer tubular member is an autogeneous bond. 22. The water reactor nuclear fuel element according to claim 11 wherein said bond between the outer circumferential surface of said inner tubular member and the inner circumferential surface of said outer tubular member is an autogeneous bond.
048470090	summary	The invention concerns a method for the loading and sealing of a double container system for the storage of radioactive material, a seal for the double container system, as well as a device for the execution of the loading and sealing method. From Swiss LP No. 650,354, a container combination is known for the transport and storage of fuel elements which consists of a removable inner container and an outer container, in which each of the containers has its own cover. The loading of the inner container takes place, as is known, in a hot cell. But the final sealing with the cover must also take place in the hot cell, which can only be accomplished with a considerable outlay, since the cover must be welded to the container. Even if the welding of the cover and container already offers good security, there is a need for a further increase in the security of the containment of the radioactive material. The object of the present invention is to provide a method and a device as well as a seal of the type which can be easily effected and make the containment of the radioactive materials even more secure. The object is achieved by means of the method comprising a series of steps including loading and sealing the radioactive material in a container within the hot cell and subsequently welding an outer cover on the container outside the hot cell. The apparatus for executing the method includes a welding and testing device mounted on a movable bridge disposed above the double container system. Advantages and practical further developments of these solutions for sealing a double container system are described in detail in this specification. In accordance with the present invention, an additional outer cover in the form of a sealing plug is provided for the inner container of the double container system. The welding of this outer cover after the inner cover has been screwed into the loaded inner container in a shielded region (hot cell), or, in the case of the double container system, locked within the cell aperture of the hot cell, takes place outside of this shielded region since the screw-type cover takes care of the required shielding of the radioactivity. Screwing the inner cover into the container inside the hot cell, or in the case of the double container system which is locked in the hot cell, requires only a comparatively low outlay. Welding outside of the shielded region (outside of a hot cell) reduces the outlay for the welding process and for the devices required considerably. By means of the additional outer cover, the containment of the radioactive materials is more secure. When we refer to radioactive material, it is understood that in the condition considered here it is enclosed in its own sheath (box, metal mould) and thus is loaded into the inner container with its sheath. All processes for loading and sealing take place on the inner container which is inserted in the shielding container. It is particularly advantageous that the welding of the outer cover to the inner container be carried out with the inner container already inserted in the shielding container.
	abstract	This invention provides a method of mounting cylindrical electrodes in the geometry of a miniature electrostatic quadrupole, which can act as a quadrupole mass filter or a quadrupole ion guide, or be used in a linear quadrupole ion trap. The electrodes are mounted in pairs on microfabricated supports, which are formed from conducting parts on an insulating substrate. The supports include a suspended flexure system to relieve strains caused by mismatch between the thermal expansion coefficients of the electrodes and the substrate. A complete quadrupole is constructed from two such supports, which are spaced apart by further conducting spacers.
047175338	description	DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, those components relating to the invention of a nuclear fuel assembly are shown. The fuel assembly comprises an upper end piece 10 and a lower end piece 12 connected together by elongated cylindrical elements 14 and 15. The elongated elements 14 and 15 are fixed to a plurality of grids 16 spaced apart along the assembly. The grids hold the fuel rods in a regular polygonal network. The assembly as shown has a hexagonal overall cross-section and the grids hold the fuel rods 18 in position at locations distributed at the apexes of equilateral triangles whose sides are parallel to the side plates which form the girdle or frame 20 of grid 16. Some locations of the network are not occupied by rods 18 but by the elongated elements 14 which may form guide tubes. Other elongated elements 15, situated at the periphery of the network, are fixed to the girdles 20 so as to form a framework of the assembly. The elements 15 may be rods or tubes. Each grid 16 comprises a plurality of mutually parallel beds of wires for holding the fuel rods in position and spacing them, fixed to girdle 20 and offset in the longitudinal direction of the assembly. As shown in FIG. 1, grid 16 has two beds of wires, perpendicular to the longitudinal axis of the assembly. Each bed consists of two series of mutually parallel wires. The wires of one of the series forming bed 24 are at 60.degree. from the wires of the two series of bed 22. The wires of the other series of bed 24 are therefore parallel to the wires of one of the series of bed 22. In the embodiment shown in FIGS. 2 and 3, the girdle is formed from flat plates to which are fixed the two beds of wires which are either undulating or are tensioned so as to be better applied against the rods and thus generate holding forces. The wires of the two series may be connected together at the crossing points, for example by welding. The plates forming the girdle are fixed, generally by welding, to the elongated elements 15, three in number for each face of the grid in the embodiment shown in FIGS. 2 and 3. The girdle may be made of "Inoconel" or from stainless steel whereas the wires will typically be made from hyper cold drawn stainless steel, although other materials are suitable. The diameter of the wires will vary depending on the pitch of the network and the diameter of the fuel rods: a wire diameter of about 0.6 mm is often of advantage. In a modified embodiment, the wires are fixed to the elongated elements 14, for example by engaging the wire ends in grooves or notches in these elements. The elongated elements 15 may then either be kept or omitted. The reactor coolant will pass through each bed of wires, around a fuel rod, essentially through two passages of generally triangular shape, as shown at a in FIG. 3. Two successive passages associated with the same rod are offset by 60.degree. when passing from one bed to the next, whether there are two beds 22 and 24 (FIG. 1) or more. Thus stirring and mixing of the different coolant streams is obtained with temperature homogeneization. The ends of the interlaced wires which form the beds are fixed to girdle 20. Numerous types of connection may be used and those which will now be described only form examples thereof which are preferable in most cases. Referring to FIG. 4, the ends of wires 26 are engaged in openings in the girdle, then locked by thermal deformation giving rise to a small boss 27. The connection may be completed by brazing. FIG. 5 shows how the same method of fixing may be applied to a grid comprising a girdle 20 having corrugations at the pitch of the rods. A split washer 29, or circlip, may be engaged on the wire before thermal deformation and brazing, for completing retention thereof (FIG. 6 and wire at the top of FIG. 4). In FIG. 4 it can be seen that the outer bosses resulting from the thermal deformation form stops for the reciprocal spacing of the fuel assemblies at the height of the grids. The reciprocal bearing points of the peripheral bosses form stops which provide radial maintenance avoiding deformation during operation in the core of the reactor. The use of circlips 28 for mounting and fixing the wires to the girdle plates means that different materials not weldable together may be used for forming the girdle on the one hand, and the wires on the other and thus allows the girdle to be made from a material chosen for its low neutron absorption. Another solution, which may be used when the grid only comprises two beds of wires or for the endmost beds of grids comprising more than two beds, is shown in FIG. 7: the ends of the wires are jammed in notches 30 in the girdle 20 before being thermally deformed and/or brazed. Whereas the grid shown in FIGS. 1 comprises only two beds of wires, the one shown in FIG. 8 comprises three parallel beds. If we designate by 1, 2 and 3 three directions at 60.degree. from each other (FIG. 8), the wires of the first bed are in directions 1 and 2, those of the second bed in directions 2 and 3 and those of the third bed in directions 3 and 1. The small dimension of the wires reduces the pressure loss. The mixture is improved because, in two successive beds, half of the wires are orientated differently. The passages a (FIG. 3) will be offset by 60.degree. when passing from one bed to the next. The successive grids provided along the whole of the assembly may be disposed so that the coolant passages are aligned along the same helix or following helical elements in a quincunx arrangement. Whereas in the case illustrated in FIGS. 3 and 4, each bed provides three pinpoint supports per rod, which results in the case of a grid of the kind shown in FIG. 8 in three pairs of double bearing points spaced apart over the periphery, the grid shown in FIGS. 9, 9A, 9B and 9C only provides two pin point supports per rod in each bed. For that, the wires of each series have a spacing double that of the wires of FIG. 3. But the wires parallel to the same direction in two different beds are offset by a half pitch, so that all the rods have the same number of bearing points (three double bearing points per rod in the case of three beds). This arrangement increases the coolant passage section offered by each bed and allows the number of beds to be increased while limiting the pressure loss to an acceptable value. Instead of disposing the beds parallel to each other, they may be given different slopes with respect to the longitudinal axis of the assembly. This solution, one embodiment of which is shown in FIG. 10, further improves the mixing of the coolant streams and more especially allows a fraction of the flow to be diverted from one assembly towards the peripheral assemblies. Several methods of mounting may be used for forming the assembly. A first solution, which may be used more especially when the wires are previously undulated and do not comprise an excessive tension, consists in aligning them in a skeleton then fitting the guide tubes and the rod. Another solution, which allows the wires to be tensioned before final fixing, consists in mounting the wires in the grids while fixing them at only one end, the other being simply inserted in the opposite plate of the grid and held without tensioning. Once the rods are positioned, the wires are subjected to a calibrated traction force then secured.
	summary
	summary
	abstract	The invention is directed to an arrangement for the generation of intensive short-wavelength radiation based on a gas discharge plasma. It is the object of the invention to find a novel possibility for generating intensive short-wavelength radiation, particularly EUV radiation, based on a gas discharge plasma which achieves a long life of the electrode system along with a high total efficiency of the radiation source without substantially increasing the dimensions of the discharge unit. This object is met, according to the invention, in that exclusively suitably shaped vacuum insulation areas which have the shape of an annular gap and which are formed depending on the product of gas pressure (p) and interelectrode distance (d) between the cathode and anode are provided for insulating the cathode and anode from one another in a cylindrically symmetric electrode arrangement for reliable suppression of electron arcing.
048200581	summary	CROSS REFERENCE TO RELATED APPLICATION Reference is hereby made to the following co-pending U.S. patent application dealing with subject matter related to the present invention: "Wear Sleeve for a Control Rod End Plug" by S. Cerni et al, U.S. Ser. No. 634,725, filed July 26, 1984. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to nuclear reactors having rods, such as of the control or water displacer type, reciprocable into and out of a reactor core and, more particularly, is concerned with a control rod end plug having an asymmetrical configuration which causes coolant axially flowing along the control rod to impart a lateral stabilizing force against the control rod which presses the control rod at its end plug against the wall of a guide thimble within which the rod reciprocably moves and thereby prevent lateral vibration of the rod. 2. Description of the Prior Art In a typical nuclear reactor, the reactor core is composed of a plurality of elongated fuel assemblies each of which contains a plurality of elongated fuel elements or rods. A liquid coolant is pumped upwardly through the core in order to extract heat generated in the core for the production of useful work. The heat output of the core is usually regulated by the movement of control rods containing neutron absorbing material such as B.sub.4 C or by movement of water displacer rods such as those described in U.S. Pat. No. 4,432,934. In reactors of the pressurized-water type, each fuel assembly typically includes a plurality of cylindrical guide tubes or thimbles through which the cylindrical control rods or water displacer rods are reciprocably moved. Some of the coolant flow is usually diverted into the lower end of the guide thimble in order to cool the control rod. The control rod ordinarily generates heat in the nuclear transformation associated with its neutron absorbing function. During power operation of the reactor, most of the regulating control rods are maintained substantially withdrawn from the reactor core and thus disposed in withdrawn positions in which the lower end plug tips of the control rods are within the upper ends of the guide thimbles. While in such withdrawn positions, the control rods may experience significant vibration induced by coolant water flow within the guide thimbles which results in oscillatory contact of the rod end plug tips against the internal wall surfaces of the guide thimbles and wear on these surfaces. Continuous wear of the guide thimble walls can lead to perforation of the thimbles and significant weakening of the fuel assembly structure. Thus, there has arisen the need to significantly mitigate the affects of the control rod vibrations so as to bring guide thimble wear under control. Two approaches to solving this problem are disclosed in U.S. Patents to Schukei et al (U.S. Pat. No. 4,292,132) and Verdone (U.S. Pat. No. 4,311,560). Both of these approaches have as a common objective the elimination of wear on the guide thimble wall by preventing vibratory contact of the control rod against its adjacent guide thimble wall. In the Verdone approach, a spring device is added to the lower end of the control rod which provides a uniform, resilient interference fit against the guide thimble wall and thereby prevents the rod tip from impacting the guide thimble wall. In the Schukei et al approach, the control rod has a hydraulic bearing formed at its lower tip which produces forces which counteract forces tending to drive the control rod tip against the guide thimble wall. In such manner, contact of the control rod against the guide thimble wall and resultant wear thereon are substantially avoided. While the approaches taken in these two patents operate reasonably well and achieve their objectives under the range of operating conditions for which they were designed, a need exists for an alternative approach to the wear problem which is simplier and less costly in its design and construction and is more reliable in its performance over the long term. SUMMARY OF THE INVENTION The present invention provides an asymmetrical configuration on the lower end plug of the control rod designed to satisfy the aforementioned needs. Unlike the prior art approaches which prevent vibratory contact with the guide thimble wall by interposing some added device which either maintains continuous contact with the wall or prevents any contact at all from occurring, the present invention merely reshapes one of the basic parts of the control rod; its end plug. Underlying the present invention is the recognition that one of the causes of coolant flow-induced vibration is vortex shedding around the tip of the end plug of the prior design. The prior end plug design, which has a symmetrical configuration about the axial centerline of the control rod, is typical of geometries which tend to promote vortex shedding and flow-induced vibration. By using an asymmetric configuration at the end plug tip, vortex shedding type of flow-induced vibration is greatly reduced. Furthermore, the present invention recognizes that lateral vibration of the control rod due to axial flow of coolant can be prevented by imposing a small, steady-state lateral force on the rod. This force can be produced by the same asymmetrical configuration which reduces vortex shedding. Such end plug shape causes non-symmetric flow velocities around the end plug tip. The magnitude of the lateral force is a function of the coolant axial flow rate and the shape of the end plug tip. Several end plug configurations will achieve these desired results of reduction of vortex shedding type of flow-induced vibration and creation of a lateral, steady-state force on the control rod. Accordingly, the present invention sets forth in a nuclear reactor including a plurality of upstanding guide thimbles, a plurality of control rods received in the guide thimbles and means supporting the control rods for movement relative to the thimbles between inserted and withdrawn positions, an end plug having an asymmetrical configuration attached to an end of each control rod which produces, in response to axial flow of coolant along the control rod and within its respective guide thimble, a lateral steady-state force on the control rod which presses the control rod end plug against a wall of the guide thimble so as to substantially prevent lateral vibration of the control rod due to the axial flow of coolant. Several different asymmetrical designs can be used to achieve non-symmetrical flow velocities around the tip of the end plug which produce the lateral force. In one design, a flat is formed, such as by machining, on one side of an otherwise axially symmetrical tapered outer surface of the end plug. Other designs have either a concave surface formed on one side of the tapered outer surface of the end plug, a tapered configuration which is offset to one side of the axis of the control rod, or a pair of flats on opposite sides of the tapered outer surface which form different angles with the axis of the control rod. These and other advantages and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
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