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	claims	1. An assembly for injecting water containing a neutron-absorbing element in order to cool a nuclear reactor core of a nuclear reactor in a crisis situation, the assembly comprising:a mobile structure, the mobile structure being configured to be transported to the nuclear reactor during the crisis situation, the mobile structure including a main pipe, the main pipe including a first end connectable to a water supply, the main pipe including a second end connectable to a circuit connected to a primary circuit of the nuclear reactor, the main pipe including, between the first and second ends, each of a pump, an injector and a first mixer;the pump being configured to cause water received from the water supply to flow in the main pipe,the injector being configured to continuously inject a neutron-absorbing element in powder form into the water in the main pipe,the first mixer being configured to mix and dissolve the injected powder in the water,the mobile structure including a controller, the controller being configured to control a flow rate of the water in the main pipe and an injection rate of the powder into the water by the injector. 2. The assembly as recited in claim 1 wherein the main pipe further includes, between the pump and the injector, a water heater regulated by the controller. 3. The assembly as recited in claim 1 wherein the mobile structure further includes a secondary pipe having a first end connectable to a water supply and a second end connectable to the main pipe between the first mixer and the second end of the main pipe, the secondary pipe including a pump between the first and second ends thereof. 4. The assembly as recited in claim 3 wherein the main pipe includes, between the second end of the secondary pipe and the second end of the main pipe, a second mixer configured for mixing the powdered neutron-absorbing element and the water in the secondary pipe. 5. The assembly as recited in claim 4 wherein the second mixer comprises a mechanical mixer. 6. The assembly as recited in claim 1 wherein the first mixer comprises a mechanical mixer and ultrasound inducers controlled by the controller. 7. The assembly as recited in claim 1 wherein the controller is configured to operate to control operation of the first mixer.
	summary
	claims	1. A boiling water reactor assembly, comprising:a control rod guide tube having a base flange;a drive housing pipe having a longitudinal axis defining an axial direction; anda bayonet plate closure coaxially connecting said drive housing pipe to said control rod guide tube, said bayonet plate closure having a two-part bayonet plate including:a) a central bayonet ring mounted rotatably about said longitudinal axis and having bayonet grooves, an underside and a periphery, andb) an outer ring mounted on said periphery of said bayonet ring, said outer ring having a concentric annular step bearing and sliding on said periphery and on said underside of said bayonet ring and said outer ring:i) reaching inward underneath said periphery of said bayonet ring, andii) being supported on said base flange of said control rod guide tube with spring pressure acting permanently on said control rod guide tube in said axial direction; anda disk spring configured to spread apart an axial distance between said bayonet ring and said base flange and apply pressure to a surface of said annular step in direction of said control rod guide tube. 2. The boiling water reactor assembly according to claim 1, wherein said disk spring surrounds said drive housing pipe with a radial sliding fit. 3. The boiling water reactor assembly according to claim 1, wherein said drive housing pipe has a tube shell and a contact surface protruding radially outwardly beyond said tube shell and having a planar shape, a conical shape or a surface with a crowned shape. 4. The boiling water reactor assembly according to claim 1, wherein said bayonet ring is braced axially while fitted on said drive housing pipe by an active spring pressure in a locked state of said bayonet plate closure. 5. A boiling water reactor assembly, comprising:a control rod guide tube having a base flange;a drive housing pipe having a longitudinal axis defining an axial direction; anda bayonet plate closure coaxially connecting said drive housing pipe to said control rod guide tube, said bayonet plate closure having a two-part bayonet plate including:a) a central bayonet ring mounted rotatably about said longitudinal axis and having bayonet grooves and a periphery, andb) an outer ring mounted on said periphery of said bayonet ring, said outer ring:i) reaching inward underneath said periphery of said bayonet ring, andii) being supported on said base flange of said control rod guide tube with spring pressure acting permanently on said control rod guide tube in said axial direction; andradially outwardly protruding retaining protrusions integrally formed at a head of said drive housing pipe and configured to reach over said bayonet ring from inside in a locked state of said bayonet plate closure. 6. The boiling water reactor assembly according to claim 5, wherein said bayonet ring has an inner side, said bayonet grooves are recesses located on said inner side of said bayonet ring complementary to said retaining protrusions at said head of said drive housing pipe, and said recesses are configured to be aligned with said retaining protrusions in a unlocked state of said bayonet plate closure. 7. A boiling water reactor assembly, comprising:a control rod guide tube having a base flange;a drive housing pipe having a longitudinal axis defining an axial direction; anda bayonet plate closure coaxially connecting said drive housing pipe to said control rod guide tube, said bayonet plate closure having a two-part bayonet plate including:a) a central bayonet ring mounted rotatably about said longitudinal axis and having bayonet grooves and a periphery, andb) an outer ring mounted on said periphery of said bayonet ring, said outer ring:i) reaching inward underneath said periphery of said bayonet ring, andii) being supported on said base flange of said control rod guide tube with spring pressure acting permanently on said control rod guide tube in said axial direction; andsaid bayonet ring being mounted rotatably on said drive housing pipe with axial play in an unlocked state of said bayonet plate closure. 8. A boiling water reactor assembly, comprising:a control rod guide tube having a base flange;a drive housing pipe having a longitudinal axis defining an axial direction; anda bayonet plate closure coaxially connecting said drive housing pipe to said control rod guide tube, said bayonet plate closure having a two-part bayonet plate including:a) a central bayonet ring mounted rotatably about said longitudinal axis and having bayonet grooves and a periphery, andb) an outer ring mounted on said periphery of said bayonet ring, said outer ring:i) reaching inward underneath said periphery of said bayonet ring, andii) being supported on said base flange of said control rod guide tube with spring pressure acting permanently on said control rod guide tube in said axial direction; andfastening pins having locking heads, reaching through said bayonet ring and configured to prevent rotation of said bayonet ring in a locked state of said bayonet plate closure.
053613775	description	DETAILED DESCRIPTION OF THE INVENTION Referring in detail now to the drawings wherein similar parts of the invention are identified by like reference numerals, and initially to the embodiment of the invention depicted in FIG. 1, there is seen a conventional nuclear generating plant, generally illustrated as 10 (i.e. Train #1) interconnected to and communicating with an improved addition, generally illustrated as 12 (i.e. Train #2) and operating in parallel with the nuclear generating plant 10. The improved addition 12 is to generally operate independent of the nucclear generating plant 10, and vice versa. During peak or high demand periods, the nuclear generating plant 10 is to be secured or disconnected communicatively from the improved addition 12 to operate independently for the production of electrical power or electricity. During low demand cycles, the improved addition 12 is to be secured or disconnected communicatively from the nuclear generating plant 10 for the independent production of electrical power or energy or electricity. The nuclear generating plant 10 in FIG. 1 comprises a steam generator 14 engaged to and communicating with a nuclear reactor 16 for generating steam therein when a heated aqueous product is passed therethrough. The heated aqueous product is produced by a plurality of heaters, generally illustrated as 18 and will be further explained in detail below. Conduit 20 extends from the steam generator 14 to a heat exchanger 22. A valve 24 controls the flow of steam through conduit 20. Conduit 26 connects to and communicates with conduit 20 downstream of valve 24 for conducting steam to a turbine (i.e. a high pressure (H.P.) turbine) 30. A control valve 28 in line or conduit 26 controls the flow of steam through conduit 26 and is capable of venting or exiting steam through conduits 32 and 34 which respectively connect to and communicate with a steam seal regulator and a heater, all to be identified below. Conduit 20 also connects to and communicates with a conduit 35 that extends to and communicates with the improved addition 12, more specifically to a superheater 36 (i.e. a fossil fired or steam to steam superheater) of the improved addition 12. Conduit 35 contains a valve 38 for controlling the flow of steam therethrough. To isolate and operate the nuclear generating plant 10 independent of the improved addition 12, valve 38 is closed and valve 24 is opened, allowing steam to flow through conduit 20 and 26 and pass respectively into heat exchanger 22 and H.P. turbine 30. H.P. turbine 30 has a shaft (not shown) that is coupled to a generator 42. A L.P. (low pressure) turbine 44 is also engaged to the same shaft for further driving and operating the generator 42 to produce electricity. As steam enters the turbine 30 to drive the same, an expansion of steam occurs. Expanded steam can exit the turbine 30 through the following conduits or lines: conduit 40, conduit 48, conduit 50, conduit 56, conduit 58 and conduit 60. Expanded steam passes through conduit 50 to enter the moisture separator/reheater 22 where steam passing through conduits 20 and 48 heats the steam. Condensate leaves the moisture separator 22 through conduit 64. Heated steam leaves the reheater 22 through a conduit 62 that connects to and communicates with the L.P. turbine 44. Some of the heated steam from the reheater 22 and passing through conduit 62 is removed through a conduit 64 to contact a feedwater turbine 66 for driving and operating a feedwater pump 68. Expanded steam leaves the feedwater turbine through conduit 70. When steam enters low pressure turbine 44, expansion of the steam takes place within turbine 44. Expanded steam leaves the turbine 44 through the following conduits or lines: conduit 74; conduit 76; conduit 78; conduit 80., conduit 82; and conduit 84. Steam passing through conduit 74, as well as steam passing through conduit 70, enters a condenser 88 to condense the steam. A steam seal regulator 90 accepts steam from conduits 32 and 40. Conduit 92 transports steam from the steam seal regulator 90 to the condenser 88. Condensate leaves the condenser 88 through the conduit 96 where pump 98 pumps the condensate through conduit 100 to introduce the same into and/or through a heater 102. As shown in the upper part of FIG. 1, conduit 100 extends through heater 102, as well as through heaters 104, 106 and 108. Each of the heaters 102, 104, 106 and 108 are basically a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More specifically, heater 108 produces an aqueous product that is conveyed to heater 106 via line or conduit 112. Similarly, heater 106 and heater 104 respectively produce an aqueous product that is conveyed to heaters 104 and 102 via line or conduit 114 and line or conduit 116 respectively. The aqueous product produced by heater 102 is conveyed to the condenser 88 via conduit 118. Expanded steam leaving the turbine 44 via conduits 78, 80, 82 and 84 is conveyed directly to heaters 102, 104 106 and 108, respectively. After leaving heater 108 conduit 100 connects to a pump 122 for pumping heated aqueous product (i.e. water) through a conduit 126 which extends through heaters 128, 130, and 132 for further heating the heated aqueous product (i.e. water) for passing or conveying further heated aqueous product into conduit 134. Conduit 126 has a valve 136 for regulating the flow of the further heated aqueous product therethrough. Expanded steam leaving the turbine via conduits 60, 58 and 56 is conveyed directly to heaters 128, 130 and 132, respectively. Conduits 20, 48 and 34 convey and introduce aqueous product into conduits 56, 58, and 60 respectively. As was seen for heaters 102, 104, 106 and 108, heaters 128, 130 and 132 are each also a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More particularly, heater 132 and 130 respectively produce an aqueous product that is conveyed to heater 130 and drain tank 146 via line or conduits 140 and 142 respectively. Heater 128 produces an aqueous product that is conveyed to the drain tank 146 via conduit 148. Drain tank 146 also receives aqueous product from conduit 64. Product leaves drain tank 146 through conduits 149 and 150 which connect to and communicate with heater 128 and a pump 152 respectively. A conduit 154 connects from pump 152 to conduit 100. Aqueous product is pumped by pump 152 through conduit 154 to conduit 100. The improved addition 12 in FIG. 1 comprises as previously indicated the superheater 36. A conduit 160 leads from the superheater 36 to a high pressure (H.P.) turbine 162. A control valve 164 in conduit 160 controls the flow of steam through conduit 160 and is capable of exiting steam through conduits 166 and 168 which respectively connect to and communicate with a steam seal regulator and a heater, all to be identified hereafter. H.P. turbine 162 has a shaft (not shown) that is coupled to a generator 170 . A L.P. (low pressure) turbine 172 is also engaged to the same shaft for further driving the generator 170 to produce electricity. As superheated steam enters the turbine 162 for operating and/or driving the same, an expansion of steam occurs. After driving the turbine 162, expanded steam exits the turbine 162 through the following conduits or lines: conduit 174, conduit 176, conduit 178, and conduit 180. Expanded steam passes through conduit 174 to enter a feedwater turbine 184 for driving and operating a feedwater pump 186. Expanded steam leaves the feedwater turbine 184 through conduit 185. A conduit 188 connects to and communicates with conduit 174 for conducting expanded steam from conduit 174 to a reheater 190. Conduit 192 conveys reheated expanded steam from the reheater 190 to the turbine 172. When steam enters the low pressure turbine 172, expansion of the steam takes place within turbine 172. Expanded steam leaves the turbine 172 through the following conduits or lines: conduit 196; conduit 198; conduit 200; conduit 202; and conduit 204. Steam passing through conduit 196, as well as steam passing through conduit 185, enters a condenser 208 to condense the steam. A steam seal regulator 210 accepts steam from conduits 166 and 176. Conduit 212 transports steam from the steam seal regulator 210 to the condenser 208. Condensate leaves the condenser 208 through the conduit 216 where pump 218 pumps the condensate through conduit 220 to introduce the same into and/or through a heater 222. As shown in the lower part of FIG. 1, conduit 220 extends through heater 222, as well as through heaters 224, 226 and 228. Each of the heaters 222, 224, 226 and 228 are basically a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More specifically, heater 228 produces an aqueous product that is conveyed to heater 226 via line or conduit 230. Similarly, heater 226 and heater 224 respectively produce an aqueous product that is conveyed to heaters 224 and 222 via line or conduit 232 and line or conduit 234 respectively. The aqueous product produced by heater 222 is conveyed to the condenser 208 via conduit 236. Expanded steam leaving the turbine 172 via conduits 198, 200, 202 and 204 is conveyed directly to heaters 222, 224 226 and 228, respectively. After leaving heater 228 conduit 220 connects to a pump 240 for pumping heated aqueous product (i.e. water) through the conduit 134 which extends through heaters 244 and 246 for further heating the heated aqueous product (i.e. water) and for passing or conveying further heated aqueous product into the steam generator 14. Conduit 134 has a valve 250 for regulating the flow of the further heated aqueous product therethrough. Expanded steam leaving the turbine 162 via conduits 178 and 180 is conveyed directly to heaters 244 and 246 respectively. Conduits 168 conveys and introduces aqueous product into the conduits 178. As was seen for heaters 222,224, 226 and 228, heaters 244 and 246 are each also a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More particularly, heater 246 and 244 respectively produce an aqueous product that is conveyed to drain tank 254 via line or conduits 256 and 258 respectively. Product leaves drain tank 254 through conduits 262 and 260 which connect to and communicate with heater 244 and a pump 264 respectively. A conduit 266 connects from pump 264 to conduit 220. Aqueous product is pumped by pump 264 through conduit 266 to conduit 220. Referring in detail now to the embodiment of the invention depicted in FIG. 6, there is seen a conventional nuclear generating plant, generally illustrated as 310 (i.e. Train #1) interconnected to and communicating with an improved addition, generally illustrated as 312 (i.e. Train #2) and operating in parallel with the nuclear generating plant 310. The nuclear generating plant 310 and the improved addition 312 operate simultaneously for the production of electrical power or electricity. The nuclear generating plant 310 in FIG. 6 comprises a steam generator 314 engaged to and communicating with a nuclear reactor 316 for generating steam therein when a heated aqueous product is passed therethrough. The heated aqueous product is produced by a plurality of heaters, generally illustrated as 318 and will be further explained in detail below. Conduit 320 extends from the steam generator 314 to a heat exchanger 322. A valve 324 controls the flow of steam through conduit 320. Conduit 326 connects to and communicates with conduit 320 for conducting steam to a turbine (i.e. a high pressure (H.P. turbine) 330. A control valve 328 in line or conduit 326 controls the flow of steam through conduit 326 and is capable of venting or exiting steam through conduits 332 and 334 which respectively connect to and communicate with a steam seal regulator and a heater, all to be identified below. Conduit 326 also has a valve 327 for securing the flow of steam therethrough. Conduit 320 also connects to and communicates with a conduit 335 that extends to and communicates with the improved addition 312, more specifically to a superheater 336 (i.e. a fossil fired or steam to steam superheater) of the improved addition 312. Conduit 335 contains a valve 338 for controlling the flow of steam therethrough. To operate the nuclear generating plant 310 simultaneously with the improved addition 312, valves 338 and 324 are opened along with the opening of metering valves 325 and 329, allowing steam to flow through conduit 320 and 326 and pass respectively into heat exchanger 322 and H.P. turbine 330 to provide warming steam. Steam is also allowed to flow into conduit 335 when valve 338 is opened. H.P. turbine 330 has a shaft (not shown) that is coupled to a generator 342. A L.P. (low pressure) turbine 344 is also engaged to the same shaft for further driving and operating the generator 342 to produce electricity. As steam enters the turbine 330 to drive the same, an expansion of steam occurs and provides warming steam. Expanded steam can exit the turbine 330 through the following conduits or lines: conduit 340, conduit 348, conduit 350, conduit 356, conduit 358 and conduit 360. Conduit 348 contains valves 349 and 351 for regulating the flow of steam therethrough. Similarly, conduits 356, 358 and 360 respectively contain valves 355, 357, 359, 361, 363 and 365 for regulating the flow of steam. Expanded steam passes through conduit 350 to enter the heat exchanger 322 where steam passing through conduits 320 and 348 heats the expanded steam and provides warming steam. Condensate leaves the heat exchanger 322 through conduit 364. Heated steam leaves the heat exchanger 322 through a conduit 362 that connects to and communicates with the L.P. turbine 344. Some of the heated steam from the heat exchanger 322 and passing through conduit 362 is removed through a conduit 364 to contact a feedwater turbine 366 for driving and operating a feedwater pump 368. Expanded steam leaves the feedwater turbine 366 through conduit 370. When steam enters low pressure turbine 344, expansion of the steam takes place within turbine 344. Expanded steam leaves the turbine 344 through the following conduits or lines: conduit 374; conduit 376; conduit 378; conduit 380, conduit 382; and conduit 384. Steam passing through conduit 374, as well as conduit 370, enters a condenser 388 to condense the steam. A steam seal regulator 390 accepts steam from conduits 332 and 340. Conduit 392 transports steam from the steam seal regulator 390 to the condenser 388. Condensate leaves the condenser 388 through conduit 396 where pump 398 pumps the condensate through conduit 400 to introduce the same into and/or through a heater 402. As shown in the upper part of FIG. 6, conduit 400 extends through heater 402, as well as heaters 404, 406 and 408. Each of the heaters 402, 404, 406 and 408 are basically a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More specifically, heater 408 produces an aqueous product that is conveyed to heater 406 via line or conduit 412. Similarly, heater 406 and heater 404 respectively produce an aqueous product that is conveyed to heaters 404 and 402 via line or conduit 414 and line or conduit 416 respectively. The aqueous product produced by heater 402 is conveyed to the condenser 388 via conduit 418. Expanded steam leaving the turbine 344 via conduits 378, 380, 382 and 384 is conveyed directly to heaters 402, 404 406 and 408, respectively. After leaving heater 408 conduit 400 connects to a pump 422 for pumping heated aqueous product (i.e. water) through a conduit 426 which extends through heaters 428, 430, and 432 for further heating the heated aqueous product (i.e. water) for passing or conveying further heated aqueous product into and through the steam generator 314. Expanded steam leaving the turbine via conduits 360, 358 and 356 is conveyed directly to heaters 428, 430 and 432, respectively. Conduits 320, 348 and 334 convey and introduce aqueous product into conduits 356, 358, and 360 respectively. As was seen for heaters 402, 404, 406 and 408, heaters 428, 430 and 432 are each also a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceeding, contiguous heater or unit. More particularly, heaters 432 and 430 respectively produce an aqueous product that is conveyed to heater 430 and drain tank 446 via line or conduits 440 and 442 respectively. Heater 428 produces an aqueous product that is conveyed to the drain tank 446 via conduit 448. Drain tank 446 also receives aqueous product from conduit 364. Product leaves drain tank 446 through conduits 449 and 450 which connect to and communicate with heater 428 and a pump 452 respectively. A conduit 454 connects from pump 452 to conduit 400. Aqueous product is pumped by pump 452 through conduit 454 to conduit 400. The improved addition 312 in FIG. 6 comprises as previously indicated the superheater 336. A conduit 460 leads from the superheater 336 to a high pressure (H.P.) turbine 462. A control valve 464 in conduit 460 controls the flow of steam through conduit 460 and is capable of exiting steam through conduits 466 and 468 which respectively connect to and communicate with a steam seal regulator and a conduit, all to be identified hereafter. H.P. turbine 462 has a shaft (not shown) that is coupled to a generator 470. A L.P. (low pressure) turbine 472 is also engaged to the same shaft for further driving the generator 470 to produce electricity. As superheated steam enters the turbine 462 for operating and/or driving the same, an expansion of steam occurs. After driving the turbine 462, expanded steam exits the turbine 462 through the following conduits or lines: conduit 474, conduit 476, conduit 478, and conduit 480. Conduit 468 connects to conduit 474. Conduits 474, 478 and 480 respectively have valves 473, 477, and 479 respectively disposed therein for regulating the flow of expanded steam therethrough, and further respectively connect to and communicate with conduits 360, 358 and 356. Expanded steam passes through conduit 474 to also enter conduit 484 which leads to a reheater 486. Expanded steam is also capable of leaving conduit 484 through a conduit 485 which connects to conduit 362. Conduit 485 has a valve 487 for regulating flow therethrough. A conduit 492 connects to and communicates with the reheater 486 for conducting reheated steam from the reheater 486 to the turbine 472. When steam enters the low pressure turbine 472, expansion of the steam takes place within turbine 472. Expanded steam leaves the turbine 472 through the following conduits or lines: conduit 496; conduit 498; conduit 500; conduit 502; and conduit 504. Steam passing through conduit 496 enters a condenser 508 to condense the steam. A steam seal regulator 510 accepts steam from conduits 466 and 476. Conduit 512 transports steam from the steam seal regulator 510 to the condenser 508. Condensate leaves the condenser 508 through the conduit 516 where pump 518 pumps the condensate through conduit 520 to introduce the same into and/or through a heater 522. As shown in the lower part of FIG. 6, conduit 520 extends through heater 522, as well as through heaters 524, 526 and 528. Conduit 520 has a valve 521 therein for regulating flow. Each of the heaters 522, 524, 526 and 528 are basically a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceding, contiguous heater or unit. More specifically, heater 528 produces an aqueous product that is conveyed to heater 526 via line or conduit 530. Similarly, heater 526 and heater 524 respectively produce an aqueous product that is conveyed to heaters 524 and 522 via line or conduit 532 and line or conduit 534 respectively. The aqueous product produced by heater 522 is conveyed to the condenser 508 via conduit 536. Expanded steam leaving the turbine 472 via conduits 498, 500, 502 and 504 is conveyed directly to heaters 522, 524 526 and 528, respectively. After leaving heater 528 conduit 520 connects to the conduit 400 of the nuclear generating plant 310. Referring in detail now to FIG. 4 for another embodiment of the present invention, there is seen a superheater 636 having a conduit 660 communicating therewith to lead superheated steam from the superheater 636 to a high pressure (H.P.) turbine 662. A control valve 664 in conduit 660 controls the flow of steam through conduit 660 and is capable of exiting steam through conduits 666 and 668 which respectively connect to and communicate with a steam seal regulator and a heater, all to be identified hereafter. H.P. turbine 662 has a shaft (not shown) that is coupled to a generator 670. A L.P. (low pressure) turbine 672 is also engaged to the same shaft for further driving the generator 670 to produce electricity. As superheated steam enters the turbine 662 for operating and/or driving the same, an expansion of steam occurs. After driving the turbine 662, expanded steam exits the turbine 662 through the following conduits or lines: conduit 674, conduit 676, conduit 678, and conduit 680. Expanded steam passes through conduit 674 to enter a feedwater turbine 684 for driving and operating a feedwater pump 686. Expanded steam leaves the feedwater turbine 684 through conduit 685. A conduit 688 connects to and communicates with conduit 674 for conducting expanded steam from conduit 674 to a reheater 690. Conduit 692 conveys reheated expanded steam from the reheater 690 to the turbine 672. When steam enters the low pressure turbine 672, expansion of the steam takes place within turbine 672. Expanded steam leaves the turbine 672 through the following conduits or lines: conduit 696; conduit 698; conduit 700; and conduit 704. Steam passing through conduit 696, as well as steam passing through conduit 685, enters a condenser 708 to condense the steam. A steam seal regulator 710 accepts steam from conduits 666 and 676. Conduit 712 transports steam from the steam seal regulator 710 to the condenser 708. Condensate leaves the condenser 708 through the conduit 716 where pump 718 pumps the condensate through conduit 720 to introduce the same into and/or through a heater 722. As shown in FIG. 4, conduit 720 extends through heater 722, as well as through heaters 724 and 728. Each of the heaters 722, 724, and 728 are basically a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceding, contiguous heater or unit. More specifically, heater 728 produces an aqueous product that is conveyed to heater 724 via line or conduit 730. Similarly, heater 724 produces an aqueous product that is conveyed to heater 722 via line or conduit 732. The aqueous product produced by heater 722 is conveyed to the condenser 708 via conduit 736. Expanded steam leaving the turbine 672 via conduits 698, 700 and 704 is conveyed directly to heaters 722, 724 and 728 respectively. After leaving heater 728 conduit 720 connects to a pump 740 for pumping heated aqueous product (i.e. water) through a conduit 634 which extends through heaters 744 and 746 for further heating the heated aqueous product (i.e. water) and for passing or conveying further heated aqueous product into and through a steam generator 614. After conduit 634 passes through the steam generator 614, it connects to and communicates with the superheater 636. The steam generator 614 is operated by a nuclear reactor 616. Expanded steam leaving the turbine 662 via conduits 678 and 680 is conveyed directly to heaters 744 and 746 respectively. Conduit 668 conveys and introduces aqueous product into the conduit 678. As was seen for heaters 722, 724, and 728, heaters 744 and 746 are each also a heat exchanger and produce an aqueous product that is passed, conducted and/or conveyed to the immediate preceding, contiguous heater or unit. More particularly, heater 746 and 744 respectively produce an aqueous product that is conveyed to the drain tank 754 via line or conduits 756 and 758 respectively. Product leaves drain tank 754 through conduit 762 and 760 which connect to and communicate with heater 744 and a pump 764 respectively. A conduit 766 connects from pump 764 to conduit 720. Aqueous product is pumped by pump 764 through conduit 766 and to conduit 720. Referring now to FIGS. 8 and 9 for two possible embodiments of the superheaters (i.e. superheater 36 or superheater 636 or superheater 336) and/or of the reheaters (i.e. reheater 486 or reheater 690 or reheater 190), FIG. 8 illustrates a fossil fired superheater or a fossil fired reheater. Cycle steam flows into the fossil fired superheater or the fossil fired reheater through piping where heat from a fossil fire heats the piping (through a heat exchange process) containing the cycle steam. After the cycle steam is heated within the piping, it exits the superheater or the reheater as heated cycle steam. Use of the fossil-fired superheater/reheater is optional for a nuclear-fossil integrated power plant utilizing a pressurized water reactor. For safety reasons, the fossil-fired superheater/reheater shall not be used for a nuclear-fossil integrated power plant utilizing a boiling water reactor. The fossil-fired superheater/reheater can be constructed as a composite unit or as a separate unit. Optionally the feedwater may be heated by use of a fuel economizer. FIG. 9 illustrates a steam to steam superheater or steam to steam reheater. Cycle steam flows into the steam to steam superheater or the steam to steam reheater through piping where heat from an entering steam heats the piping (through a heat exchange process) containing the cycle steam. After the cycle steam is heated within the piping, it exits the superheater or the reheater as heated cycle steam. Use of the superheater/reheater heat exchanger is optional for a nuclear-fossil integrated power plant utilizing a pressurized water reactor. For safety reasons, the heat exchanger shall be used for a nuclear-fossil integrated power plant utilizing a boiling water reactor. The superheater/reheater heat exchanger can be constructed as a composite unit or as a separate unit. Optionally, the feedwater may be heated by use of a fuel economizer when a fossil-fired boiler is used. My invention will be illustrated by the following set forth examples which are given by way of illustration and not by any limitation. All parameters such as distances, concentrations, temperatures, mixing proportions, pressures, flow-rates, heat rates, enthalpy, entropy, compounds, temperature rates, times, etc., submitted in these examples are not to be construed to unduly limit the scope of my invention. The following three examples of the Nuclear-Fossil Integrated Power Plant invention are submitted for illustrative purposes only since other design innovations or embodiments are within the scope of the present invention. Such embodiments could include a fuel economizer for utilizing the fossil stack heat and/or a separate superheated steam loop as described below. Two of the embodiments or design innovations are presented in heat balance form with matching expansion lines shown on their respective Mollier diagrams. The design attributes are derived by comparing the Design innovation (Nuclear-Fossil Integrated Steam Cycle) to the original Nuclear Plant design information (Nuclear Steam Cycle). Utilizing the same feedwater flow to the steam generator and the original nuclear plant design configuration, the three embodiments and innovations are described and compared in the following Examples: EXAMPLE I General Arrangement This example is directed to the embodiment of the invention in FIG. 1. In this design the heat balance sheet of the original plant configuration (Nuclear Steam Cycle) is shown in the upper diagram of FIG. 1. Valves and interconnect piping have been added and permits the directing of the steam flow from the steam generator 14 in Train #1 to either Train #1 via conduit 20 or to Train #2 via conduit 35. Train #1 in FIG. 1 Operation Explanation When Train #1 is operated 15,136,752 lbs/hr of feedwater enters and exits the steam generator 14 via conduit 126. The steam coming from the steam generator 14 through conduit 20 is 1000 PSIA and is saturated (see A1 on the FIG. 1 diagram and on the Mollier diagram in FIG. 2). Valve 38 in conduit 35 is closed. Valve 2A is open which allows 913,081 lbs/hr of steam to flow to the second stage of the heat exchanger 22 and 14,223,671 lbs/hr of steam to flow through control valve 28 and enter the H.P. unit (turbine) 30 (see A2 in the upper part of FIG. 1 for steam conditions). The steam expands through the H.P. unit 30 to 175.3 PSIA (see A3 in the upper part of FIG. 1 for steam conditions). This expansion occurs below the saturation line and exits the H.P. unit 30 as wet steam. The Mollier diagram of FIG. 2 shows that the steam at A3 conditions has a 14% moisture content. It should be noted that the turbine blading in the H.P. unit 30 must be protected from the erosion effects of this moisture. Along the expansion path in the H.P. unit 30 steam @430.6 PSIA, @277.1 PSIA and @175.3 PSIA is respectively extracted through conduits 56, 58 and 60 for three feedwater heaters 132, 130 and 128 respectively and through conduit 48 for the 1st stage of the heat exchanger 22. This reheater or heat exchanger 22 extraction flow through conduit 48 is 485,233 lbs/hr The H.P. unit 30 generates in the generator 42 426.4 megawatts of power. The unit 22 shown between the H.P. unit (turbine) 30 and the L.P. unit (turbines) 44 is a combination moisture separator and heat exchanger 22. 1,687,414 lbs/hr of water (moisture) is separated in the moisture separator via conduit 64 resulting from the H.P. unit 30 exit flow through conduit 50 (shown as 12,030,591 lbs./hr) thus reducing the flow of steam through conduit 62 to 10,343,177 lbs/hr. After this moisture removal, the steam is saturated steam and its enthalpy condition is shown on the Mollier diagram in FIG. 2 where the dotted line between A3 and A4,5 crosses the saturation line at an enthalpy of about 1196.2 H in BTU/lb. This value of 1196.2 H is listed in the entrance of the 1st stage of the heat exchanger 22 @172.1 PSIA. The reheater 22 is a 2 stage heat exchanger using the 485,233 lbs/hr of H.P. unit 30 extraction steam via conduit 18 in the 1st stage and 913,081 lb/hr of main steam via conduit 20 in the 2nd stage thus heating 10,343,177 lbs/hr of steam exiting the heat exchanger 22 through conduit 62 to a superheat condition with an enthalpy of about 1279.1 H (see A4 and A5 in the upper part of FIG. 1 for steam conditions). 193,860 lbs./hr of steam is channeled from conduit 62 via conduit 64 and is used to drive the F. W. Pump Unit 66/68 (193,860 lbs/hr) and 10,149,317 lbs./hr of steam enters the L.P. unit 44 (10,149,317 lbs/hr) via conduit 62. Along the expansion path in the L.P. unit 44, steam is extracted via conduits 84, 82, 80 and 78 respectively for 4 feedwater heaters 108, 106, 104 and 102 respectively at the respective pressure of @98.7 PSIA, @59.7 PSIA, @18.7 PSIA and @9.25 PSIA. Additionally moisture is separated through conduit 76 @4.9 PSIA (187,921 lbs/hr) from the steam flow path. The steam exits the L.P. unit 44 with high moisture content (see A6 in the upper part of FIG. 1 for steam conditions). The L.P. unit 44 generates in the generator 42 780.3 megawatts. Train #1 in FIG. 1 generates a net total of 1185.8 megawatts of power with a heat rate of about 9854.6 BTU/KWH. This heat rate represents an efficiency of about 34.6%. Train #2 in FIG. 1 Explanation Train #2 in FIG. 1 provides a Nuclear-Fossil Integrated Steam Cycle by directing saturated steam from Train #1 via conduit 35 to Train #2 (see F1 on the upper part of FIG. 1 for steam condition) with valve 24 and valve 38 open. The steam flows to the super-heater 36 in Train #2. (Note: In the pressurized water reactor plant the superheater 36 and reheater 190 (previously described) are heat exchangers with heat being provided by a fossil-fired firebox (see FIG. 8) or a separate superheated steam loop (see FIG. 9). If the steam generator 14 utilizes a boiling water reactor, the superheater 36 and the reheater 190 (previously described) utilizes a separate superheated steam loop. This loop is shown on the conceptual design configuration FIG. 9. The super-heater 36 heats the saturated steam from conduit 35 to a superheated condition of 1000.degree. F. (see F2 on the lower part of FIG. 1 for steam conditions). In turn, the steam enters the Train #2 H.P. unit through conduit 160 @1000.degree. F. and 930 PSIA (see F3 on the lower part of FIG. 1 for the steam conditions). It is noteworthy to mention that all of the feedwater is heated to a superheated steam condition by the superheater 36 and is delivered to the H.P. unit 162 via conduit 160. In the Train #1 configuration (original design) 14,223,671 lbs/hr enters the H.P. unit 30 from conduit 26. In the Train #2, 15,136,752 lbs/hr enters the Train #2 H.P. unit 162 from conduit 160. This increased flow coupled with the use of superheated steam generates 727.9 megawatts in the generator 170 from the Train #2 H.P. unit 162. The Train #1 H.P. unit 30 generates 426.4 megawatts. Additionally the slope of the extraction line on the FIG. 2 and 3 Mollier diagram is an indication of the turbine efficiency, 87.0% for Train #1 H.P. unit 30 and 89.8% for Train #2 H.P. unit 162. (This is due to the lack of moisture in the steam. The efficiencies are noted on the heat balance diagram of FIG. 1). Since the Train #2 H.P. unit 162 utilizes superheated steam, the erosion effect of moisture in the steam that exists during the Train #1 H.P. unit 30 operation is nonexistent during Train #2 H.P. unit operation 162, thus a 3600 rpm unit is used. Only 2 feedwater heaters 246 and 244 are utilized since the extraction steam has a higher heat content. The H.P. unit 162 exit pressure of about 233 psa is higher (see F4 in the lower part of FIG. 1 for steam conditions) than the exit pressure from H.P. unit 30 (see A3 on FIG. 1 for steam conditions). After exiting the H.P. unit 162 (see F4 in the lower part of FIG. 1 for steam conditions) the steam enters the reheater 190 and is reheated to 1000.degree. F., 208 PSIA (see F5 in the lower part of FIG. 1 for steam conditions). The steam flows through conduit 192 and is expanded through the L.P. unit 172 and utilizes 4 extraction conduits 204, 202, 200 and 198 to respectively direct expanded steam to 4 L.P. heaters 228, 226, 224 and 222 respectively at the pressures designated on FIG. 1. The steam exits at 4% moisture (see F6 in the lower part of FIG. 1 for steam conditions). This permits the use of a 3600 rpm unit. The power output is 1641.9 megawatts. The expansion line for Train #2 shows a large amount of available heat (1528.9-1059.0); that is a delta enthalpy of about 469.9 H. Train #1 has a delta enthalpy of about 323.9 H (1279.1-955.2) available. Additionally the flow to Train #2 L.P. unit 172 is about 13,289,477 lb/hr. Train #1 L.P. unit 44 steam thereto through conduit 50 flow is about 10,149,317 lb/hr operating as a nuclear steam cycle. The result is that the Train #1 generates about 1185.8 megawatts wherein Train #2 operating as a nuclear-fossil integrated steam cycle generates about 2330.0 megawatts, a 1144.2 megawatt increase which is a 96.5% increase. Overall Design Attributes The power is increased about 1144.2 megawatts, that is from 1185.8 megawatts to 2330.0 megawatts, a 96.5% increase. The heat rate for the power increase (1144.2 megawatts) is 6374.9 BTU/KWH which is 53.5 efficiency. The average fossil plant has a heat rate of 8800 BTU/KWH (39.0% efficient). The Example I fossil fuel utilization represents a 27% fuel savings. (Note: a new high tech fossil plant design using a critical pressure and 1050.degree.-1100.degree. F. steam can be designed for a maximum of 42% efficiency--which is 8124 BTU/KWH). Lower capital cost since 3600 rpm turbine-generator equipment is used. Regulatory approval is simplified. Construction of Fossil addition can be accomplished during plant operation and tie-in can be accomplished during normal refueling outage. Train selection can be based on power demand. Train selection can be switched when one train is not operable. Train maintenance will not have to be accomplished during a refuel-maintenance outage; therefore outage time can be reduced from the usual 60-100 day refuel-maintenance outage to a refuel outage of 20 to 24 days for refueling the reactor. This will increase the availability factor. Additional maintenance and modification cost will be greatly reduced since the usual 600-800 man outage force will not be required since all maintenance and modifications can be accomplished on one train by utility maintenance and modification personnel while the other train is in use. Each of the above attributes results in a substantial yearly gross income/profit increase. EXAMPLE II General Arrangement This Example is directed to the embodiment of the invention in FIG. 6. In this design the heat balance sheet of the original plant configuration (nuclear steam cycle) is shown on the upper diagram of FIG. 6. In this embodiment of the invention, Train #2 operates simultaneously with Train #1. The upper diagram (Train #1) in FIG. 6 shows the original plant configuration modified with the necessary valves to permit the utilization of all the Train #1 feedwater heaters, (i.e. 402, 404, 406,4 08, 428, 430 and 432) and the use of the Train #1 L.P. unit (turbine) 344. Additionally metering valves are utilized to provide warming steam to the Train #1 piping, the Train #1 reheater or heat exchanger 322 and the Train #1 H.P. unit (turbine) 330. Additionally it should be noted that in the FIG. 6 the exit steam temperature from the superheater 336 has been selected to assure the exit steam conditions from the Train #2 H.P. unit (turbine) 462 are about the same as reheater or heat exchanger 322 steam conditions when Train #1 is operated in the original design configuration or nuclear steam cycle to permit use of the Train #1 L.P. unit. These steam conditions are pictorial evidenced on the Mollier diagrams (see A4, 5 in FIG. 2) and H 4,5 in FIG. 7). The FIG. 6 Design Innovation results in a lower total capital cost since the feedwater heaters and the L.P. unit 344 in Train #1 are all utilized. This arrangement permits the directing of saturated steam flow from the steam generator 314 in Train #1 to either Train #1 (thus functioning as the original nuclear steam cycle) or to Train #2 superheater 336 (thus functioning as the nuclear-fossil integrated steam cycle or a Train 1-Train 2 composite unit). Train #1 in FIG. 6 Operation Explanation The FIG. 6 Heat Balance Diagram shows the valve positions for the Train #1-Train #2 composite operation. For the Train #1 operation, each of the valves 338, 479, 477, 473, 487 and 521 are changed from open to a closed position therefore Train #1 will function in accordance with original design configuration (nuclear steam cycle). A detailed description of the FIG. 6 Train #1 fluid flows, fluid conditions, and power generation, etc. operating as a nuclear steam cycle is given in the previously mentioned FIG. 1 Train #1 operation explanation of Example I. Train #1-Train #2 Composite Unit in FIG. 6 Operation Explanation As explained in the "General Arrangement" paragraph above, the Train #1 feed water heaters (i.e. 402 etc.) and Train #1 L.P. unit 344 are utilized and the Train #1 piping, the Train #1 reheater 322 and Train #1 H.P. unit 330 are provided with warming steam. Additionally the saturated steam (see H1 in FIG. 6 for steam conditions as well as on the FIG. 7 Mollier diagram) is directed through conduit 335 from the Train #1 steam generator 314 to the Train #2 superheater 336. The Train #1 steam generator 314 receives from conduit 426 about 15,136,752 lbs/hr of feedwater, and subsequently generates about 15,136,752 lbs/hr of saturated steam @1,000 PSI. About 69,561 lbs/hr of steam is directed through conduit 326 to the Train #1 H.P. unit 330 and about 10,000 lbs/hr of steam is directed via conduit 320 to the Train #1 reheater or heat exchanger 332, thus about 15,057,191 lbs/hr of steam enters the Train #2 superheater 336. The 15,057,191 lb/hr exits the Train #2 superheater 336 @ 920.degree. F. and 950 PSIA (see H2 in FIG. 6 for steam conditions). Note: In the pressurized water reactor plant the superheater and reheater (previously described) are heat exchangers with heat being provided by a fossil-fired fire box or a separate superheated steam loop utilizing a fossil-fired fire box. If the steam generator 314 utilizes heat from a boiling water reactor, the superheater and reheater (previously described) utilizes a separate superheated steam loop utilizing a fossil-fired fire box. This loop is shown on the conceptual design of FIG. 9. In turn, the steam enters the Train #2 H.P. unit 462 from conduit 460 @930 PSIA (see H3 in FIG. 6 for steam conditions). The steam expands through the H.P. unit 462 to 175.3 PSIA (see H4 in FIG. 6 for steam conditions). It is noteworthy to mention that in the Train #1 FIG. 1 design configuration, 14,223,671 lbs/hr enters the H.P. unit 30 but in the FIG. 6 Train #2 H.P. unit 462 15,057,191 lbs/hr enters H.P. unit 462 through conduit 460. This increased flow coupled with the use of superheated steam generates 784.4 megawatts in the Train #2 H.P. unit 462. The FIG. 1 Train #1 H.P. unit 30 when operated in the nuclear steam cycle (original design) generates 426.4 megawatts. Additionally the slope of the extraction line on the Mollier diagram is an indication of the turbine efficiency, 87.0% for FIG. 1 Train #1 H.P. unit and 89.8% for FIG. 6 Train #2 H.P. unit. (This is due to the lack of moisture in the steam. The efficiencies are noted on the Heat balance diagram of FIGS. 1 and 6). Since the Train #2 H.P. unit 462 utilizes superheated steam, the erosion effect of moisture in the steam that exists during the Train #1 H.P. unit 330 operation is non-existent during the Train #2 H.P. unit 462 operation; thus a 3600 rpm unit is used. Steam is extracted from the Train #2 H.P. unit 462 and is respectively directed to the Train #1 feedwater heaters 432, 430 and 428 respectively via conduit 480, 478 and 474 respectively. Additionally saturated steam which was metered to the Train #1 H.P. unit 330 and to Train #1 reheater 322, flows from the H.P. unit 330 to the heaters (i.e. 432,430,etc.) as shown on the FIG. 6 heat balance diagram. At the exit of the Train #2 H.P. unit 462 the exit enthalpy and pressure is about the same as the Train #1 design configuration reheater exit or heat exchanger 22 conditions, (see H4 in FIG. 6 and A4 in FIG. 1). This flow enters the FIG. 6 Train #1 L.P. unit 344 respectively @160 PSIA, 1279.1 H (enthalpy). (see H5 in FIG. 6) The exit flow from the FIG. 6 Train #2 H.P. unit 462 is 13,783,141 lbs/hr (13,219,126+564,015). To duplicate the design configuration flow to the Train #1 H.P. unit and to the feedwater pump unit, the Train #2 H.P. unit 462 exit flow through conduit 474 is split. 10,343,177 lb/hr is directed through conduits 474 and 485 to Train #1 and the balance of the flow (2,836,266 lbs/hr) is directed through conduits 484 to the Train #2 reheater 486. 10,149,317 lbs/hr of steam from conduit 362 is expanded through the Train #1 L.P. unit 344. Extracted steam via conduits 378, 380, 382, and 384 provides steam or heat for the Train #1 heaters (i.e. heaters 402, 404, 406, and 408). The steam exits through conduits 374 and 376 into the Train #1 condenser 388 (see H8 in FIGS. 6 and 7 for the steam conditions), and about 780.3 megawatts of power are generated by generator 344. The Train #2 reheater 486 steam flow (2,886,266 lbs/hr) enters the Train #2 L.P. unit 472 @150 PSIA, 920.degree. F., 1489.0 H (see H6 in FIGS. 6 and 7 for the steam conditions). The steam is expanded through the Train #2 L.P. unit 472. Extraction steam via conduits 498, 500, 502 and 504 respectively supplies heat to the Train #2 L.P. heaters (522,524,525 and 528). The steam exits via conduit 496 into the Train #2 condenser 508 (see H7 in FIGS. 6 and 7 for the steam conditions). The steam exits @4% moisture which permits the use of a 3600 rpm unit. 321 megawatts of power are generated in the Train #2 L.P. unit 472. The expansion line on the FIG. 7 Mollier diagram shows a large amount of available heat. This along with the increased flow within the turbine units results in a total power production increase. The power production of FIG. 1 Train #1 operating as a Nuclear steam cycle (original configuration) generates 1185.8 megawatts, wherein the composite unit in FIG. 6 operating as Nuclear-Fossil integrated steam cycle generates 1856.6 megawatts, a 670.8 megawatts increase which is a 56.6% power increase. Example II Overall Design Attributes The power is increased 670.0 megawatts, that is from 1185.8 megawatts to 1856.6 megawatts, a 56.6% increase. The heat rate for the increased power (670.0 mw) is 6981.7 BTU/KWH which is 48.9% efficient. The average fossil plant has a heat rate of 8800 BTU/KWH (39.0% efficient). The FIG. 6 fossil fuel utilization represents a 21% fuel savings. (Note: A new high tech fossil plant design using critical pressure and 1050.degree.-1100.degree. F. steam can be designed for a maximum of 42% efficiency--which is 8024 BTU/KWH). Lower capital cost since 3600 rpm turbine-generator equipment may be utilized. Regulatory approval is simplified. Train selection can be based on power demand. Each of the above attributes results in a substantial yearly gross income/profit increase. EXAMPLE III General Arrangement The Example is directed to the embodiment of the invention in FIGS. 4 and 5. The general arrangement of this innovation is as follows: Nuclear operated steam generator 614 is employed having a feedwater flow therethrough via conduit 634 of about 7,800,000 lbs/hr. The steam generator 614 uses a U-tube design. Therefore the exit steam generator steam conditions via conduit 634 utilized in the FIG. 4 heat balance is 1000 PSIA saturated steam and the entrance feedwater temperature into steam generator 614 via conduit 634 is 439.8.degree. F. Five feedwater heaters 722, 724, 728, 744, and 746 have been utilized. Additionally FIG. 4 employs a steam superheater 636, and a reheater 690, and superheater and reheater temperatures and pressure drops, piping and control valves, gland leakages, operating pressures and turbine efficiencies are all used as suggested on the previous examples. 3600 RPM turbines are utilized and the expansion line shown on the Mollier Diagram in FIG. 5 is identical to the FIG. 1 expansion line, with condenser pressure of 1.5 in Hg and L.P. unit 672 exit steam @4% moisture. The heat balance diagram in FIG. 4 and Mollier diagram in FIG. 5 with the expansion line are all illustrated. FIG. 4 Operation Explanation 7,800,000 lbs/hr of feedwater @439.8.degree. F. enters the steam generator 614 via conduit 634 and exits @1000 PSIA (see G1 in FIGS. 4 and 5 for steam conditions) and is saturated steam. The 7,800,000 lbs/hr of saturated steam is piped to the superheater 636 via conduit 634 and heated to 1000.degree. F. (see G2 in FIGS. 4 and 5 for steam conditions). 7,797,306 lbs/hr enters the H.P. unit (turbine) 662 through conduit 660 (see G3 in FIGS. 4 and 5 for steam conditions) and exits @233.0 PSIA (see G4 in FIGS. 4 and 5 for steam conditions). Two steam extractions through conduits 678 and 680 occur within the H.P. unit 662 for feedwater heating in heaters 744 and 746. The H.P. unit 662 causes the generator 670 to generate 374.8 megawatts. The H.P. unit 662 exit steam via conduit 674 is utilized for the feedwater pump turbine unit 684 and the balance (6,850,260 lbs/hr) is piped through conduit 688 to the reheater 690 which heats the steam to 1000.degree. F. (see G5 in FIGS. 4 and 5 for steam conditions). 6,850,260 lbs/hr of steam enters the L.P. unit 672 and exits the L.P. unit 672 via conduit 696 @1.5 inches of H.sub.g and 4% moisture (see G6 in FIGS. 4 and 5 for steam conditions). Three extractions occur via conduits 698, 700 and 704 respectively within the L.P. unit 672 for feedwater heating of feedwater passing through conduit 720 which extends through heaters 722, 724 and 728. The L.P. unit 672 cause the generator 670 to generate 842.7 megawatts. This Example operates as a nuclear-fossil integrated steam cycle and produces 1197.6 megawatts. Since this Example produces 1197.6 megawatts, this is an increase of 597.6 megawatts a 99.6% increase over a nuclear steam cycle which utilizes saturated steam and with a moisture separator/reheater. (Note: such a unit would produce 600 megawatts). FIG. 4 Overall Design Attributes The power is increased 597.6 megawatts; that is from 600 megawatts to 1197.6 megawatts, a 99.6% increase. The heat rate for the increased power (597.6 MW) is 6296.9 BTU/KWH which is 54.2% efficient. The average fossil plant has a heat rate of 8800 BTU/KWH (39.0% efficient). The FIG. 4 fossil fuel utilization represents a 29% fuel savings. (Note: a new high tech fossil plant design using critical pressure and 1050.degree.-1100.degree. F. steam can be designed for a maximum of 42% efficiency which is 8124 BTU/KWH). Lower capital cost since 3600 RPM turbine-generator equipment may be utilized in lieu of new generation nuclear plant 1800 RPM equipment. Lower capital cost since single installation produces double the power. Each of the above attributes results in a substantial yearly gross income/profit increase. Thus by the practice of the present invention there is provided an apparatus and method that combines the best of the nuclear fueled and the fossil fired systems. The present invention utilizes the normal nuclear cycle for the generation of saturated steam. In turn, the saturated steam is superheated using a fossil fired or steam to steam superheater and utilizes the superheated steam in a 3600 RPM H.P. turbine. The H.P. turbine exhaust steam is then superheated in a fossil fired or steam to steam reheater and flows on to the L.P. turbine. This adds more heat for a given fluid flow, hence higher power production. Additionally, nuclear fuel is used for the water to steam transformation, hence the low cost fuel has been utilized for this major heat input. Since the superheating of the steam is accomplished using fossil fuel, the following advantages are obtained with the apparatus and method of the present invention: (1) the steam flow which was used for reheat in the conventional nuclear fueled system is available for power production in the practice of the present invention; and (2) the use of superheated steam made available by the nuclear-fossil integrated system permits more heat to be added to the fluid flow resulting in added power production and the use of 3600 RPM H.P. and L.P. turbines. In summary, the low cost nuclear BTU's are used for the "boiling" of the water into steam and the more costly fossil BTU's are used to superheat the steam. While the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure, and it will be appreciated that in some instances some features of the invention will be employed without a corresponding use of other features without departing from the scope of the invention as set forth.
	summary
	description	The present application claims priority from U.S. Provisional Patent Application Ser. No. 60/470,176 filed on May 13, 2003, which is assigned to the assignee of the present application and incorporated herein by reference. The present invention generally relates to the field of medical radiography, and more particularly to a method of making an X-ray anti-scatter grid for use in patient diagnostic imaging procedures. Scattered X-ray radiation (sometimes referred to as secondary or off-axis radiation) is generally a serious problem in the field of radiography. Scattered X-ray radiation is a particularly serious problem in the field of X-ray patient diagnostic imaging procedures, such as mammographic procedures, where high contrast images are required to detect subtle changes in patient tissue. Prior to the present invention, scattered X-ray radiation in patient diagnostic imaging procedures has been reduced through the use of a conventional linear focused scatter-reducing grid. The grid is interposed between the patient and an X-ray detector and tends to allow only the primary, information-containing radiation to pass to the detector while absorbing secondary or scattered radiation which contains no useful information about the patient tissue being irradiated to produce an X-ray image. (05) Some conventional focused grids used in patient diagnostic imaging procedures generally comprise a plurality of X-ray opaque lead foil slats spaced apart and held in place by aluminum or fiber interspace filler. In focused grids, each of the lead foil slats, sometimes referred to as lamellae, are inclined relative to the plane of the film so as to be aimed edgewise towards the focal spot of the X-rays emanating from an X-ray source. Usually, during an imaging procedure, the standard practice is to move the focused grid in a lateral direction, perpendicular to the lamellae, so as to prevent the formation of a shadow pattern of grid lines on the X-ray image, which would appear if the grid were allowed to remain stationary. Such moving grids are known as Potter-Bucky grids. One problem with conventional grids of the type described above is that the aluminum or fiber interspace filler material absorbs some of the primary, relatively low energy, information-containing X-ray radiation. Because some of the primary radiation is absorbed by the interspace material, the patient must be exposed to a higher dose of radiation than would be necessary if no grid were in place in order to compensate for the absorption losses imposed by the grid. It is an obvious goal in all radiography applications to expose the patient to the smallest amount of radiation needed to obtain an image having the highest image quality in terms of film blackening and contrast. Another problem with such conventional focused grids of the parallel lamellae type described above is that they do not block scattered radiation components moving in a direction substantially parallel to the plane of the lamellae. Two-dimensional grids remove more scattered radiation for a given thickness of grid. However, the presence of walls at right angles mean that there is no direction which is perpendicular to all the walls, which makes moving the grids much more difficult. U.S. Pat. No. 5,606,589 to Pellegrino, et al. discloses air cross grids for absorbing scattered secondary radiation and improving X-ray imaging in general radiography and in mammography. The grids are provided with a large plurality of open air passages extending through each grid panel. These passages are defined by two large pluralities of substantially parallel partition walls, respectively extending transverse to each other. Each grid panel is made by laminating a plurality of thin metal foil sheets photo-etched to create through openings defined by partition segments. The etched sheets are aligned and bonded to form the laminated grid panel, which is moved diagonally and a precise number of periods during the X-ray exposure to pass primary radiation through the air passages while absorbing scattered secondary radiation arriving along slanted paths. Proper movement of the grid is very critical, but is also difficult, resulting in significant reliability problems. The method of Pellegrino, et al. produces sturdy cellular air cross grids having focused air passages offering radiation transmissivity about equal to the best linear grids presently available. However, it has been found that the etching method of Pellegrino, et al. does not produce grids with very fine and precise dimensions, as desired. What is still desired are improved apparatuses and methods for making focused anti-scatter grids with more transmission and better uniformity. Preferably, such improved apparatuses and methods will be relatively easier, less time-consuming and less expensive than existing techniques for making focused anti-scatter grids. Exemplary embodiments of the present invention provide a new and improved method for making anti-scatter grids. One exemplary embodiment of a method according to the present invention for manufacturing an anti-scatter grid includes arranging a plurality of elongated metal ribbons of radio-opaque material so that each ribbon is substantially straight and lies in a plane that passes through a focal point of the grid, and placing the elongated ribbons under tension. A first sheet of radiolucent material(also referred to herein as “radioluscent ”material) is secured to top edges of the ribbons, and a second sheet of radioluscent material is secured to bottom edges of the ribbons. The ribbons are arranged such that the first and second radioluscent sheets are substantially parallel. The the tension is removed from the ribbons. The resulting grid is a structural sandwich that is very rigid even though it is made from flexible components. The present invention also provides a new and improved anti-scatter grid including a plurality of elongated metal ribbons of radio-opaque material. Each ribbon is held substantially straight, under tension, and lies in a plane that passes through a focal point of the grid. The ribbons are arranged so that top edges of the ribbons are substantially parallel and so that bottom edges of the ribbons are substantially parallel. The grid also includes a first sheet of radioluscent material secured to the top edges of the ribbons, and a second sheet of radioluscent material secured to the bottom edges of the ribbons. The ribbons are arranged such that the first and second radioluscent sheets are essentially parallel. Additional aspects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein exemplary embodiments of the present invention are shown and described, simply by way of illustration of the best modes contemplated for carrying out the present invention. As will be realized, the present invention is capable of other and different embodiments and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. X-ray imaging uses the fact that x-rays “R” are extremely penetrating but are absorbed by the material “B” (such as a patient's body through which they pass. An x-ray image is the two-dimensional map of the x-ray absorption of the material “B” lying between an x-ray source located at a focal point “FP” and an X-ray detector located at a detector plane “DP”. FIG. 1 shows a typical medical x-ray imaging situation. The quality of the image depends on the fact that a significant fraction of the x-rays R are absorbed rather than scattered. Referring to FIG. 2, Ray R is emitted from the source located at the focal point FP and detected at point P by the X-ray detector located at the detector plane DP. Ray R1 scatters and is also detected at the point P. Ray R2 is totally absorbed and, therefore, not detected. In the making of an image, occurrences such as these happen many millions of times. The fact that R1 scattered and was detected at P causes density along the ray R1 to be appropriately assigned to the point P1. However, the point P receives radiation from the ray R1 and, therefore, the density along the ray R is measured to be lower than it actually is. Since scattering occurs in all directions, there is very little spatial information contained in the scattered radiation. The scattered radiation tends to blur the image and lower the measured absorption of localized regions of high absorption. This problem can be ameliorated by placing a grid 10 of plates 12 in front of the X-ray detector DP which prevents the scattered radiation from reaching the detector, as shown in FIG. 3. The grid 10 is formed of a high atomic number material, such as tungsten or tantulum. Each of these plates 12 should be positioned so that the focal spot FP lies in the plane of the plate 12. As illustrated in FIG. 3, it is clear that scattered radiation emanating from outside region (a) will not be detected; a fraction of the radiation emanating from the two regions labeled (b) and directed towards the region (a) will be detected; and all the radiation emanating from (c) and directed towards the region (a) will be detected. Furthermore, it is clear that this grid 10 will remove some of the unscattered radiation because the plates 12 have a finite thickness “t” and that the geometric efficiency of the grid 10 is (p−t)/p or A/p where “p” is the period of the grid and “A” is the area between the plates 12. It is also clear that the effectiveness of the grid 10 in removing scattered radiation increases as the ratio h/p increases, where “h” is the height of the grid 10 in the direction of the x-ray beam. Referring now to FIGS. 4 and 5, an exemplary embodiment of a new and improved anti-scatter grid 100 constructed in accordance with the present invention is shown. The grid 100 is a sturdy and highly useful implement in the X-ray patient diagnostic imaging field, and provides the desired absorption of scattered secondary radiation. The anti-scatter grid 100 includes a plurality of elongated metal ribbons 102 of radio-opaque material. Each ribbon is held substantially straight, under tension, and lies in a plane that passes through a focal point of the grid. The ribbons 102 are arranged so that top edges 104 of the ribbons 102 are substantially parallel and so that bottom edges 106 of the ribbons 102 are substantially parallel. The grid also includes a first sheet 108 of radioluscent material secured to the top edges 104 of the ribbons 102, and a second sheet 110 of radioluscent material secured to the bottom edges 106 of the ribbons 102. The ribbons 102 are arranged such that the first and second radioluscent sheets 108, 110 are parallel. The grid 100 is a structural sandwich that is very rigid even though it is made from flexible components. In one exemplary embodiment, the ribbons 102 are each placed under tension. Ends 112 of the ribbons 102 do not extend beyond ends 109, 111 of the first and second radioluscent sheets 108, 110, and the ends 112 of the ribbons 102 and ends 109, 111 of the first and second radioluscent sheets 108, 110, as well as sides 113, 115 of the sheets 108, 110 can be potted with a thin beam 114 of epoxy. If necessary, at least one of the first and second radioluscent sheets 108, 110 can include holes 116 to allow pressure equalization within spaces between the ribbons 102. In the exemplary embodiment shown in FIGS. 4 and 5, the first and second radioluscent sheets 108, 110 are secured to the ribbons 102 with layers of adhesive 118 while the ribbons are under tension. In particular, the radioluscent sheets 108, 110 are provided as previously cured carbon/epoxy sheets 108, 110 coated with the thin uniform layer of adhesive for securing the sheets 108, 110 to the ribbons 102. Alternatively, the first and second radioluscent sheets 108, 110 can be provided as semi-hardened sheets 108, 110 of epoxy impregnated carbon fiber cloth which is secured to the ribbons 102 by pressing the sheets 108, 110 against the ribbons 102 and allowing the sheets 108, 110 to cure. In any event, the first and second radioluscent sheets 108, 110 each have a thickness of about between 0.25 mm and 0.5 mm in accordance with one possible embodiment of the invention. When the sheets 108 and 110 are bonded to the ribbons 102, the ribbons 102 are cut down to the ends 109, 111 of the sheets 108, 110. The edges of this structure are then potted in four steps (one for each side) which stabilizes and strengthens the assembly. The metal ribbons 102 are can be made of tungsten or tantalum, for example. In one exemplary embodiment, the grid has dimensions of 24 cm×30 cm or 18 cm×24 cm, with the ribbons 102 extending perpendicular to the long dimension. The ribbons 102 are spaced about 0.3 mm apart, and the plurality of ribbons 102 comprises about one-thousand (1,000) ribbons 102. In one exemplary embodiment, the ribbons 102 are each about twenty-four (24) cm long, about two (2) mm wide, and about fifteen (15) to eighteen (18) microns thick. The grid 100 shown in FIGS. 4 and 5 is a one-dimensional grid 100, but could also be provided in the form of a two-dimensional grid. Although not shown, a two-dimensional grid can be provided. In a two-dimensional grid, the plurality of elongated metal ribbons comprise a first set and the anti-scatter grid further comprises a second set of a plurality of elongated metal ribbons of radio-opaque material. Each ribbon of the second set is held substantially straight, under tension, and lies in a plane that passes through a focal point of the grid, and the ribbons of the second set are arranged so that top edges of the ribbons of the second set are substantially parallel and so that bottom edges of the ribbons of the second set are substantially parallel. The bottom edges of the ribbons of the second set are secured to the second sheet of radioluscent material, and a third sheet of radioluscent material is secured to the top edges of the ribbons of the second set. The second set of ribbons are also arranged such that the second and the third radioluscent sheets are substantially parallel. In one exemplary embodiment, the first and the second set of ribbons are arranged so that the first set of ribbons extends substantially perpendicular to the second set of ribbons. The present invention also provides methods for making the focused anti-scatter grid 100 of FIGS. 4 and 5. One exemplary embodiment of a method 200 according to the present invention for manufacturing the anti-scatter grid 100 includes arranging a plurality of the elongated metal ribbons 102 of radio-opaque material so that each ribbon is substantially straight and lies in a plane that passes through a focal point of the grid. Then, the elongated ribbons 102 are placed under tension, and the first sheet 108 of radioluscent material is secured to the top edges 104 of the ribbons 102, and the second sheet 110 of radioluscent material is secured to bottom edges 106 of the ribbons 102. The ribbons 102 preferably have been arranged such that the first and second radioluscent sheets 108, 110 are parallel. After the sheets 108, 110 have been secured to the ribbons 102, the tension is removed from the ribbons 102. The method 200 provides a grid 100 that is a structural sandwich that is very rigid even though the grid 100 is made from flexible components, such as the thin ribbons 102 and the thin sheets 108, 110. The new and improved linear grid 100 of the present invention has been found to provide a much better transmission than existing two-dimensional grids. The ribbons 102 are very thin (e.g., 0.012 mm) and the cover sheets 108, 110 are thin and very low atomic number (e.g., 0.25 mm thick and made of carbon fiber and epoxy). The new and improved linear grid 100 of the present invention is also an improvement because the grid simply has air between the ribbons 102. Furthermore, the one-dimensional grid 100 is easier to move than a two-dimensional grid since the extra set of grid walls in the two-dimensional grid provides artifacts. It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the construction set forth without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
055330746	claims	1. An apparatus for determining a level of coolant in a nuclear reactor system, said nuclear reactor system having a pressurizer and a coolant loop, said coolant having a temperature and a density, said apparatus comprising: first sensor means for sensing pressure in said pressurizer, said first sensor means issuing a first signal related to said pressure sensed in said pressurizer; second sensor means for sensing pressure in said coolant loop, said second sensor means issuing a second signal related to said pressure in said coolant loop; and controller means responsive to said first and said second sensor means for calculating said level of said coolant of said nuclear reactor from said first and said second signals. first pressure transmitter means for sensing pressure in said pressurizer and issuing a first signal related to said pressure sensed in said pressurizer; second pressure transmitter means for sensing pressure in said coolant loop, said second sensor means issuing a second signal related to said pressure in said coolant loop; controller means responsive to said first and said second sensor means for calculating said level and a rate of change of said coolant of said nuclear reactor from said first and said second signals. first pressure transmitter means for sensing pressure in said upper location and issuing a first signal related to said pressure sensed in said upper location; second pressure transmitter means for sensing pressure in said lower location, said second sensor means issuing a second signal related to said pressure in said lower location; and controller means responsive to said first and said second sensor means for calculating said level of said coolant of said nuclear reactor from said first and said second signals. generating a first signal related to the pressure in said pressurizer; generating a second signal related to the pressure in said coolant loop; calculating the level of said coolant from the difference in said first and said second signals. 2. The apparatus as recited in claim 1, wherein said first and said second sensor means are pressure transmitters. 3. The apparatus as recited in claim 1, wherein said first and said second sensor means are pressure transducers, and said first and second signals are electrical signals. 4. The apparatus as recited in claim 1, wherein said first and said second sensor means each comprise a plurality of pressure transmitters. 5. The apparatus as recited in claim 1, further comprising means in electrical connection with said controller means for visually displaying a signal corresponding to said level calculated by said controller means. 6. The apparatus as recited in claim 1, wherein said controller means, in calculating said level, compensates for said temperature of said coolant. 7. The apparatus as recited in claim 1, wherein said controller means, in calculating said level, compensates for said density of said coolant. 8. An apparatus for determining a level of coolant in a nuclear reactor system, said nuclear reactor system having a pressurizer and a coolant loop, said coolant having a temperature and a density, said apparatus comprising: 9. The system as recited in claim 8, wherein said controller compensates for temperature and density of said coolant in calculating said level. 10. The system as recited in claim 8, wherein said first and said second sensor means each comprises a plurality of pressure transmitters. 11. The system as recited in claim 8, wherein said first and said second sensor means each comprises a plurality of pressure transmitters, and said controller selects a high signal from among said plurality of pressure transmitters of said first sensor means and a low signal from among said plurality of pressure transmitters of said second sensor means. 12. The system as recited in claim 8, wherein said second sensor means further comprises a plurality of pressure transmitters pairs, each pair of said plurality of pairs being located in a different part of said coolant loop. 13. The system as recited in claim 8, wherein said first sensor means operates in a range of pressures from about 30 inches of mercury vacuum to about 15 PSIG. 14. The system as recited in claim 8, wherein said second sensor means operates in a range of pressures from about 30 inches of mercury vacuum to about 50 PSIG. 15. An apparatus for determining a level of coolant in a nuclear reactor system, said nuclear reactor system having an upper location and a lower location, said upper location being above an uppermost expected level of said coolant, said lower location being below a lowermost expected level of said coolant, said coolant having a temperature and a density, said apparatus comprising: 16. The system as recited in claim 15, wherein said controller compensates for temperature and density of said coolant in calculating said level. 17. The system as recited in claim 15, wherein said first and said second sensor means each comprises a plurality of pressure transmitters. 18. The system as recited in claim 15, wherein said first and said second sensor means each comprises a plurality of pressure transmitters and said controller selects a high signal from among said plurality of pressure transmitters of said first sensor means and a low signal from among said plurality of pressure transmitters of said second sensor means. 19. The system as recited in claim 15, wherein said second sensor means further comprises a plurality of pressure transmitters pairs, each pair of said plurality of pairs being located in said lower level. 20. The system as recited in claim 15, wherein said first sensor means operates in a range of pressures from about 30 inches of mercury vacuum to about 15 PSIG, and said second sensor means operates in a range of pressures from about 30 inches of mercury vacuum to about 50 PSIG. 21. A method for determining the level of coolant in a nuclear reactor system, said nuclear reactor system having a pressurizer and a coolant loop in fluid communication with said pressurizer, said method comprising the steps of: 22. The method as recited in claim 21, further comprising the step of compensating said difference for temperature of and boron concentration in said coolant.
	summary
	description	This invention was made with Government support under Contract No. DE-NE0000633 awarded by the Department of Energy. The Government has certain rights in this invention. This disclosure generally relates to systems, devices, structures, and methods associated with control rod position indicator systems for a nuclear power reactor. In many types of pressurized water reactors (PWR) and boiling water reactors (BWR), a reactor core may contain a large number of fuel rods that are several meters in height. The reactor core may be surrounded by water contained within a reactor vessel. Additionally, the reactor may contain one or more control rod drive mechanism (CRDM) assemblies including a number of control rod assemblies that may be inserted into, and withdrawn from, the reactor core to control the overall power level of the reactor. The CRDM assembly may include a number of magnetic coils operable to raise and lower the control rod assemblies. For example, the magnetic coils may be used to move the control rod assemblies out of the reactor core in incremental steps. Many CRDM assemblies are designed such that a loss of electrical power will result in the magnetic coils automatically releasing the control rod assemblies into the reactor core, in what is referred to as a reactor trip or scram. The CRDM assembly may additionally comprise sensing coils aligned along a direction of motion of a control rod which, when actuated, may pass through the center of the sensing coils as the control rod is moved. In known CRDM assemblies, the sensing coils may be associated with a control rod position indicator (RPI) assembly. The RPI assembly may comprise numerous sensing coils. Each sensing coil may comprise or be associated with two terminals. In an example for an RPI assembly that includes 78 sensing coils, there may be 156 terminals and/or 156 wires associated with each of the control rods. Additionally the CRDM assembly may be associated with dozens of control rods, which has the effect of similarly multiplying the total number of wires in the RPI assembly. Some known RPI assemblies may be located within a containment structure that houses the reactor vessel. The wires associated with the RPI assembly may have one end attached at or near the top of the reactor vessel, and another end that passes through the containment structure to transmit the information to an external processing device and/or monitor. A number of penetrations through the containment structure may therefore be associated with the multitude of wires of the RPI assembly. Additionally, known RPI assemblies may comprise or be associated with two separate power supplies. Each of the power supplies may be configured to supply voltage to half of the sensing coils. Utilizing two power supplies may be configured to allow the sensing coils to continue operating at lower resolution if one of the power supplies is shut off or otherwise becomes inoperable. Some RPI assemblies may utilize a dual common bus power supply. Each of the sensing coils corresponding to the dual common bus power supply may have one of its two corresponding terminations connected to the bus. The other termination may be separately fed out of the containment structure for processing. Although the number of terminations passing through the containment structure may be approximately half as many as compared to RPI assemblies associated with two power supplies, there may still be 78 or more wires that need to pass through the containment structure for the example RPI assembly provided above, having 78 sensing coils. Accordingly, the large number of wires associated with known RPI assemblies creates a significant challenge to maintain a sealed containment structure due to the number and/or size of the penetrations that are required to pass the wires through the containment structure. Additionally, the large number of wires causes significant complexity and a corresponding amount of time to label, connect, disconnect, route, or otherwise handle the wires during manufacture, installation, maintenance, operation, and/or decommissioning of the reactor module. This application addresses these and other problems. A rod position indication system is disclosed herein, comprising a drive rod operably coupled to a control rod that is configured to be both withdrawn from and inserted into a reactor core. A number of sensing devices may be linearly arranged along a path of the drive rod, and an end of the drive rod may be configured to pass by or through one or more of the sensing devices in response to the movement of the control rod with respect to the reactor core. The sensing devices may be arranged into a plurality of groups, and each group may include two or more of the sensing devices electrically coupled together. In some examples, the two or more of the sensing devices may be electrically coupled together in series. The rod position indication system may further comprise a control rod monitoring device electrically coupled to each group of sensing devices by a separate routing wire. A method of determining a position of a control rod is disclosed herein, comprising moving the control rod relative to a reactor core. The control rod may be operably coupled to a drive rod of a control rod drive mechanism, and the drive rod may be configured to move relative to a number of sensing devices associated with a rod position indication (RPI) apparatus in response to withdrawing the control rod. A change in electrical property of a first sensing device may be detected based, at least in part, on an end of the drive rod located proximately to the first sensing device. The first sensing device may be associated with a first group of sensing devices electrically coupled together. The method may further comprise receiving, at the RPI apparatus, a first signal associated with the change in electrical property of the first sensing device. Additionally, a change in electrical property of a second sensing device may be detected based, at least in part, on the end of the drive rod located proximately to the second sensing device. The second sensing device may be associated with a second group of sensing devices electrically coupled together. In some examples, one or both of the first group of sensing device and the second set of sensing devices may be separately coupled together in series. The RPI apparatus may be configured to receive a second signal associated with the change in electrical property of the second sensing device. The first signal may be compared to the second signal to determine the position of the drive rod relative to the number of sensing devices. An apparatus for performing a method of determining a position of a control rod in a nuclear reactor is also disclosed herein. FIG. 1 illustrates a cross-sectional view of an example reactor module 40 comprising a reactor pressure vessel 52. Reactor pressure vessel 52 may house a reactor core 6 located near a lower head 55 of the reactor pressure vessel 52. A riser section 24 is located above the reactor core 6. Coolant circulates past the reactor core 6 to become high-temperature coolant TH and then continues up through the riser section 24 where it is directed back down the annulus and cooled off by a heat exchanger to become low-temperature coolant TC. A control rod drive mechanism (CRDM) 10 operatively coupled to a number of drive shafts 20 may be configured to interface with a plurality of control rod drive assemblies located in reactor core 6. The reactor pressure vessel baffle plate 45 may be configured to direct the coolant (shown as coolant flow 26) towards the lower head 55 of the reactor pressure vessel 52. A surface of the reactor pressure vessel baffle plate 45 may come into direct contact with and deflect the coolant that exits the riser section 24. In some examples, the reactor pressure vessel baffle plate 45 may be made of stainless steel or other materials and/or may be formed into an ellipsoidal shaped surface. The lower head 55 of the reactor pressure vessel 52 may comprise an ellipsoidal, domed, concave, or hemispherical portion 55A. The ellipsoidal portion 55A may be configured to direct the coolant (shown as coolant flow 28) towards the reactor core 6. The ellipsoidal portion 55A may increase flow rate and promote natural circulation of the coolant through the reactor core 6. The reactor pressure vessel baffle plate 45 is illustrated as being located between the top of the riser section 24 and a pressurizer region 15 located in an upper head 56 of the reactor pressure vessel 52. The pressurizer region 15 is shown as comprising one or more heaters and spray nozzles configured to control a pressure, or maintain a steam dome, within the upper head 56. Coolant located below the reactor pressure vessel baffle plate 45 may comprise relatively sub-cooled coolant at temperature TSUB, whereas coolant in the pressurizer region 15 in the upper head 56 of the reactor pressure vessel 52 may comprise substantially saturated coolant at temperature TSAT. A fluid level of the coolant is shown as being above the reactor pressure vessel baffle plate 45, and within the pressurizer region 15, such that the entire volume between the reactor pressure vessel baffle plate 45 and the lower head 55 of the reactor pressure vessel 52 may be full of coolant during normal operation of the system 40. A lower riser 22 may support one or more control rod guide tubes or instrumentation structures. The one or more control rod guide tubes or instrumentation structures may be attached to the riser section 24, and serve to guide control rod assemblies that are inserted into, or removed from, the reactor core 6, or provide support for instrumentation devices located inside the reactor pressure vessel 52. In some examples, control rod drive shafts may pass through reactor pressure vessel baffle plate 45 and through riser section 24 in order to control the position of the control rod assemblies relative to reactor core 6 Reactor pressure vessel 52 may comprise a flange by which lower head 55 may be removably attached to a vessel body 60 of reactor pressure vessel 52. In some examples, when the lower head 55 is separated from vessel body 60, such as during a refueling operation, riser section 24, baffle plate 45, and other internals may be retained within vessel body 60, whereas reactor core 6 may be retained within lower head 55. Additionally, vessel body 60 may be housed within a containment vessel 70. FIG. 2 illustrates an upper cross-sectional view of a reactor module 200 and an example control rod drive mechanism (CRDM) assembly 225. Reactor module 200 may comprise an upper containment vessel 250 housing at least a portion of the CRDM assembly 225. For example, a plurality of drive shaft housings 240 may be located within upper containment vessel 250. Additionally, a plurality of drive shafts 275 associated with CRDM assembly 225 may be located in a reactor pressure vessel 210 that is housed in a main containment vessel 220. Drive shaft housings 240 may be configured to house at least a portion of drive shafts 275 during operation of reactor module 200. In some examples, essentially all of the CRDM assembly 225 may be housed within main containment vessel 220. Upper containment vessel 250 may be removably attached to main containment vessel 220. By removing upper containment vessel 250, the overall size and/or volume of reactor module 200 may be reduced, which may affect peak containment pressure and/or water levels. In addition to reducing the overall height of reactor module 200, the removal of upper containment vessel 250 from main containment vessel 220 may further reduce the weight and shipping height of reactor module 200. In some example reactor modules, several tons of weight can be removed for each foot that the overall height of reactor module 200 is decreased. Reactor pressure vessel 210 and/or main containment vessel 220 may comprise one or more steel containment vessels. Additionally, main containment vessel 220 may comprise one or more flanges, similar to flange 80 (FIG. 1), by which a top head or a bottom head of main containment vessel 220 may be removed from the containment vessel body, such as during a refueling operation. During refueling, reactor module 200 may be relocated from an operating bay into a refueling bay, and a series of disassembly steps may be performed on the reactor module 200. The operating bay may be connected to the refueling bay by water, such that reactor module 200 is transported under water. Main containment vessel 220 may be disassembled, e.g., the top or bottom head may be separated from the containment vessel body, in order to gain access to CRDM assembly 225 and/or to reactor pressure vessel 210. At this stage of refueling, reactor pressure vessel 210 may remain completely sealed to the surrounding water in the refueling bay. In some examples, an upper portion of CRDM assembly 225, such as the plurality of drive shaft housings 240, may be located above water to facilitate access to CRDM assembly 225 in a dry environment. In other examples, the entire CRDM assembly 225 may be submerged in the pool of water in the refueling bay. CRDM assembly 225 may be mounted to an upper head of reactor pressure vessel 210 by a mounting structure 230. Mounting structure 230 may be configured to support CRDM assembly 225 when main containment vessel 220 is partially or completely disassembled during the refueling operation. Additionally, CRDM assembly 225 may be configured to support and/or control the position of drive shafts 275 within reactor pressure vessel 210. Reactor pressure vessel 210 may comprise a substantially capsule-shaped vessel similar to reactor pressure vessel 52 (FIG. 1). In some examples, reactor pressure vessel 210 may be approximately 20 meters in height. Drive shafts 275 may extend from CRDM assembly 225, located at the upper head of reactor pressure vessel 210, into a lower head of reactor pressure vessel 210, so that they can be connected to control rod assemblies that are inserted into the reactor core. The distance from the upper head of reactor pressure vessel 210 to the reactor core, such as reactor core 6 (FIG. 1), while less than the overall height of reactor pressure vessel 210, may therefore result in the length of drive shafts 275 also being approximately 20 meters in length or, in some examples, somewhat less than the height of reactor pressure vessel 210. Main containment vessel 220 and/or upper containment vessel 250 may include one or more penetrations, such as penetration 280. The one or more penetrations may provide through-holes for instrumentation cabling or wires to pass through the containment wall. For example, wiring associated with CRD assembly 225, such as wiring for a rod position indicator system located inside of the containment vessel, may pass through the penetrations to operably couple CRD assembly 225 to a processor or monitor located outside of the containment vessel. The penetrations may be sealed to the environment, such that any air or water located outside of the containment vessel is not allowed to enter the containment vessel through the penetrations. In some examples, penetration 280 may be associated with a wire connector, configured as circular plate sealed to the containment vessel, which may be used to route a plurality of wires. FIG. 3A illustrates cross-sectional view of an example reactor pressure vessel 300 and a CRDM assembly 325. CRDM assembly 325 may be mounted to an upper head 320 of reactor pressure vessel 300 and configured to support a plurality of drive shafts 375 that extend through the length of a vessel body 310 of reactor pressure vessel 300 towards a reactor core 360 located in a lower head 315 of reactor pressure vessel 300. In some examples, lower head 315 may be removably attached to vessel body 310 at a flange 390, such as by a plurality of bolts. In addition to housing a number of fuel rods, reactor core 360 may be configured to receive a plurality of control rod assemblies 365 that may be movably inserted between the fuel rods to control the power output of reactor core 360. When reactor core 360 is generating power, lower ends 370 of drive shafts 375 may be connected to control rod assemblies 365. Additionally, CRDM assembly 325 may be configured to control the location of control rod assemblies 365 within reactor core 360 by moving drive shafts 375 either up or down within reactor pressure vessel 300. Upper ends 380 of drive shafts 375 may be housed in a CRDM housing 340 located above upper head 320 of reactor pressure vessel 300, such as when control rod assemblies 365 are removed from reactor core 360. In some examples, CRDM housing 340 may comprise a single containment structure configured to house upper ends 380 of drive shafts 375. In other examples, CRDM housing 340 may comprise individual housings for each of the drive shafts 375. Lower ends 370 of drive shafts 375 are shown disconnected from control rod assemblies 365, such as may be associated with a refueling operation of reactor core 365. During an initial stage of the refueling operation, lower head 315 may remain attached to vessel body 310 while drive shafts 375 are disconnected from control rod assemblies 365. The reactor pressure vessel 310 may remain completely sealed to the surrounding environment, which in some examples may comprise a pool of water that at least partially surrounds reactor pressure vessel 310, during the initial stage of the refueling operation. CRDM assembly 325 may comprise a remote disconnect mechanism by which drive shafts 375 may be disconnected from control rod assemblies 365 without opening or otherwise disassembling reactor pressure vessel 300. In some example, reactor pressure vessel 300 may form a sealed containment region 305 that surrounds reactor core 360, control rod assemblies 365, and lower ends 370 of drive shafts 375. By remotely disconnecting drive shafts 375, control rod assemblies 365 may remain within reactor core 360 when drive shafts 375 are withdrawn, at least partially, into CRDM housing 340. FIG. 3B illustrates the example reactor pressure vessel 300 of FIG. 3A partially disassembled. During the refueling operation, lower head 315 may be separated from vessel body 310 of reactor pressure vessel 300. In some examples, lower head 315 may be held stationary in a refueling station while vessel body 310 is lifted up by a crane and moved away from lower head 315 to facilitate access to reactor core 360. Drive shafts 375 are shown in a retracted or withdrawn position, such that lower ends 370 may be completely retained within vessel body 310 and/or CRDM housing 340. For example, CRDM assembly 325 may be configured to raise lower ends 370 of drive shafts 375 above a lower flange 394 used to mount vessel body 394 together with an upper flange 392 of lower head 315. Withdrawing lower ends 370 of drive shafts 375 into vessel body 310 may provide additional clearance between lower flange 394 and upper flange 392 during the refueling operation and further may keep drive shafts 375 from contacting external objects or getting damaged during transport and/or storage of vessel body 310. Additionally, upper ends 380 of drive shafts 375 may similarly be housed and/or protected by CRDM housing 340 when drive shafts 375 are in the retracted or withdrawn position. As discussed above, control rod assemblies 365 may remain completely inserted in reactor core 360 during some or all of the refueling operation. In some examples, maintaining the insertion of control rod assemblies 365 within reactor core 360 may be dictated by nuclear regulatory and/or safety considerations. FIG. 4 illustrates a block diagram of an example control rod drive mechanism (CRDM) assembly 400. CRDM assembly 400 may comprise a drive mechanism 410 configured to raise and lower a drive shaft 475. Drive shaft 475 is shown with broken lines to indicate the relative length may vary depending on the distance (e.g., several feet to twenty or more meters) between drive mechanism 410 and the control rod assemblies contained in the reactor core. A lower end of drive shaft 475 may comprise a coupling mechanism 425. The coupling mechanism 425 may be configured to removably couple drive shaft 475 to the top of a control rod assembly. Additionally, CRDM assembly 400 may comprise a pressure housing 420, a latch assembly 430, a drive shaft housing 440, and a rod position indication (RPI) system 450. CRDM assembly 400 may be mounted to a reactor pressure vessel. Pressure housing 420 may be configured to provide a pressure boundary about drive shaft 475 at a penetration point through the reactor pressure vessel. In some examples, pressure housing 420 may be inserted into and/or welded to the upper head of a reactor pressure vessel, such as upper head 320 (FIG. 3). Drive shaft housing 440 may be configured to house an upper end of drive shaft 475 as it is raised from the reactor core. Additionally, the RPI system 450 may be configured to determine the position of drive shaft 475 as it is removed from, or inserted into, the reactor core. FIG. 5 illustrates an example CRDM assembly 500 comprising a control rod drive disconnect system. A drive mechanism 510 may be configured to raise and lower a drive shaft 525 through a pressure housing 520 and/or through a latch assembly 530. In some examples, latch assembly 530 may be contained within pressure housing 520. Latch assembly 530 may comprise a plurality of latches and/or magnetic plungers configured to interact with a number of electro-magnetic coil arrangements, such as a first magnetic coil assembly 511, a second magnetic coil assembly 512, and a third magnetic coil assembly 513. Latch assembly 530 may be configured to incrementally or continuously vary the position of drive shaft 575 by energizing or otherwise actuating one or more of the number of magnetic coil assemblies 511, 512, 513. In some examples, one or more of the magnetic coil assemblies 511, 512, 513 may comprise and/or be referred to as a stationary gripper coil, a moveable gripper coil, and a lift coil, respectively. Additionally, a fourth magnetic coil assembly 514 comprising a magnetic coil 555, one of more flux rings 552, and one or more magnetic poles 556 may be configured to interact with a latch assembly 550. Magnetic coil assembly 514 and latch assembly 550 may be configured to move and/or otherwise control the position of a CRD disconnect apparatus 580 relative to drive shaft 575. In some examples, latch assembly 550 may be housed within latch assembly housing 530 and magnetic coil 555 may be located outside of latch assembly housing 530. CRD disconnect apparatus 580 be operably coupled to a disconnect rod 525 at least partially housed within drive shaft 575. Additionally CRD disconnect apparatus 580 may be configured to move and/or to allow movement of disconnect rod 525 relative to drive shaft 575. For example, the control rod drive disconnect system may be configured to hold drive shaft 575 in a relatively fixed position and to move disconnect rod 525 within the stationary drive shaft 575. In another example, the control rod drive disconnect system may be configured to hold disconnect rod 525 in a relatively fixed position and to move drive shaft 575. CRDM assembly 500 may be configured to controllably position drive shaft 575 located at least partially within a reactor pressure vessel. An upper end of drive shaft 575 may be located outside of the reactor pressure vessel. One or more of the plurality of latch devices associated with magnetic coil arrangements 511, 512, 513 may be configured to engage, hold, and/or move the upper end of drive shaft 575. A lower end of drive shaft 575 may be operably coupled to the control rod assembly in a sealed containment region of the reactor pressure vessel. Latch assembly 550 and/or CRD disconnect apparatus 580 may be configured to engage disconnect rod 525. In response to an actuation of CRD disconnect apparatus 580 while the lower end of drive shaft 575 remains in the sealed containment region, the lower end of drive shaft 575 may be uncoupled from the control rod assembly due to a relative movement between disconnect rod 525 and drive shaft 575. The reactor pressure vessel may comprise a lower head removably attached to a vessel body, as illustrated in FIGS. 3A and 3B. CRD disconnect apparatus 580 may be actuated while the lower head remains attached to the vessel body. In some examples, the control rod drive disconnect system described with reference to magnetic coil assembly 514, latch assembly 550, and CRD disconnect apparatus 580 may comprise an electro-magnetic coil, a magnetic plunger, and one or more grippers and/or latches similar to components used with the CRDM coil stacks and/or other components that may be used to control the overall position of drive shaft 575, such as one or more of magnetic coil assemblies 511, 512, 513. FIG. 6 illustrates an example rod position indicator (RPI) system 600. RPI system 600 may comprise a plurality of sensing coils, such as a first sensing coil 610, a second sensing coil 620, a third sensing coil 630, a fourth sensing coil 640 and one or more additional sensing coils such as a sensing coil 680 and a lower sensing coil 690. The plurality of sensing coils may be housed in a RPI sensor housing 650. Additionally, a drive rod 675 or a drive shaft connected to a control rod may be configured to move up and down through the sensing coils during one or more operations of the nuclear reactor. Each of the sensing coils may be associated with two wires and/or terminals. For example, first sensing coil 610 may be associated with a first wire 612 connected to a first terminal 605, and a second wire 614 connected to a second terminal 615. Similarly, second sensing coil 620 may be associated with wires 622, 624 connected to corresponding terminals of second sensing coil 620. Additionally, third sensing coil 630 may be associated with wires 632, 634, and fourth sensing coil 640 may be associated with wires 642, 644. The one or more additional sensing coils, such as sensing coil 680 and lower sensing coil 690, may also be associated with two wires, such as wires 682, 684 and wires 692, 694, respectively, connected to corresponding terminals of the additional sensing coils. As current is applied to one or more of the coils, a magnetic field may be generated. As drive rod 675 passes through each coil, the inductance of the coil may be altered. When the control rod is inserted into the reactor core, drive rod 675 may not extend into some or all of the upper coils 610, 620, 630, and/or 640 and, therefore, the upper coils may have a relatively low inductance. As the control rod is retracted from the reactor core, drive rod 675 will eventually extend into one or more of the upper coils 610, 620, 630, 640, which may cause the inductance of the upper coils to increase. In some examples, the location of the control rod may be determined from the difference in output voltages between adjacent coils. Output voltages associated with any one of the coils may be measured and/or otherwise determined from one or both wires that are operably coupled to the terminals of each coil. As mentioned above, the inductance of a particular coil may increase in response to the end of drive rod 675 entering a coil, such as sensing coil 630. The increased inductance of the coil may similarly increase the impedance of the coil and lower the output voltage of the coil as compared to a coil in which drive rod 675 has not been inserted, such as sensing coil 620. Each of the coils may be electrically coupled to a voltage source by a first wire and/or terminal. The voltage source may be configured to feed an AC voltage through each of the coils. Additionally, the coils may be electrically coupled to the voltage source by a second, neutral, and/or grounded wire. Where each of the coils are electrically coupled to two wires, there may be twice as many wires as the number of coils. In some examples, the wires may pass through, or out of, RPI sensor housing 650. Additionally, the wires may pass through, or be routed out of, a surrounding containment structure, such as main containment vessel 220 and/or upper containment vessel 250 (FIG. 2). In an example RPI system where there are 78 sensing coils, 156 wires may be routed out through the containment structure. FIG. 7 illustrates a simplified schematic diagram for an example RPI system 700 with a dual common bus power supply. The dual common bus power supply may comprise a first bus 770 and a second bus 775. First bus 770 may be configured to provide a voltage supply to a first half of the coils, such as sensing coil 610, sensing coil 630, and one or more additional coils such as sensing coil 680. First bus 770 may be electrically coupled to coils 610, 630, 680 by wires 612, 632, 682, respectively. Similarly, second bus 775 may be configured to provide a voltage supply to a second half of the coils, such as sensing coil 620, sensing coil 640, and one or more additional coils such as sensing coil 690. Second bus 775 may be electrically coupled to coils 620, 640, 690 by wires 624, 644, 694, respectively. First bus 770 and second bus 775 may be associated with two separate power supplies. Each power supply may be configured to supply 24 volts, or some other value. In some examples, the sensing coils may be electrically coupled to the buses in an alternatingly configuration. A first coil, such as sensing coil 610 may be electrically coupled to first bus 770 and a second coil, such as sensing coil 620 may be electrically coupled to second bus 775. Similarly a third coil, such as sensing coil 630 may be electrically coupled to first bus 770 and a fourth coil, such as sensing coil 640 may be electrically coupled to second bus 775. Subsequent and/or consecutive coils of the RPI system may be similarly coupled to the buses in an alternating fashion. In some examples, an RPI system with alternating coils may be configured to continue operating at a lower resolution if a power supply associated with one of the buses becomes inoperable, is turned off, or otherwise stops supplying a voltage signal. For example, RPI system 700 may be configured to detect when the end of a drive rod is located between any two coils coupled to first bus 770, such as between sensing coil 610 and sensing coil 630, when no voltage is being supplied to sensing coil 620 by second bus 775. By using one or more buses, the number of wires that are routed out through a surrounding containment structure, such as main containment vessel 220 and/or upper containment vessel 250 (FIG. 2), may be reduced. For example, half of the wires that are electrically coupled to the coils, such a wires 614, 622, 634, 642, 684, and 692 may be routed through the containment structure, whereas a second half of the wires, such as wires 612, 624, 632, 644, 682, and 694 may remain completely within the containment structure while coupling the coils to the one or more buses. For an RPI system where there may be 78 sensing coils, only 78 wires may be routed through the containment structure instead of 156 if no buses are used. In some examples, in addition to the half of the wires that are routed out through containment structure, first bus 770 and/or second bus 775 may also be routed out through the containment structure. RPI system 700 may be configured to detect when a voltage difference occurs between two adjacent coils, such as sensing coil 620 and sensing coil 630, and based on the voltage difference may determine that the end of drive rod 675 is located within sensing coil 630 and/or between sensing coil 630 and the adjacent or next sensing coil 620 located above the end of drive rod 675. In some examples, the voltages associated with the coils may be measured or otherwise determined from one or more wire that are electrically coupled to the coils opposite the buses. For example, a voltage associated with sensing coil 620 may be measured on wire 622, and a voltage associated with sensing coil 630 may be measured on wire 634. Additionally, RPI system 700 may be configured to determine that the end of drive rod 675 is proximate to or above sensing coil 630 until another difference in voltage is detected between two adjacent coils. For example, a subsequent difference in voltage as between sensing coil 620 and sensing coil 610 may indicate that the control rod is in the process of being withdrawn from the reactor core, whereas a subsequent difference in voltage as between sensing coil 630 and sensing coil 640 may indicate that the control rod is in the process of being inserted into the reactor core. FIG. 8 illustrates a block diagram for an example RPI system 800 with a plurality of grouped coil arrangements. A first group of coils 810 may comprise three or more coils, such as coils 811, 812, and 813. Similarly, a second group of coils 820 may comprise coils 821, 822, 823, a third group of coils 830 may comprise coils 831, 832, 833, a fourth group of coils 840 may comprise coils 841, 842, 843, etc. In some examples, half of the groups of coils may be electrically coupled to a first bus 870 and a second half of the groups of coils may be electrically coupled to a second bus 875. Additionally, the groups of coils may be coupled to the buses in an alternating or staggered arrangement. For example, the first and third groups of coils 810, 830 may be electrically coupled to first bus 870 and the second and fourth groups of coils 820, 840 may be electrically coupled to second bus 875. Coils associated with the first group of coils 810 may be electrically coupled to each other in series. For example, coil 811 may be coupled to coil 812 by a connecting wire 814 and coil 812 may be coupled to coil 813 by a further connecting wire 816. Additionally, coil 813 may be electrically coupled to first bus 870 by a bus connection wire 815. The second group of coils 820 may also comprise a number of connecting wires 824 and 826 to couple coils 821, 822, and 823 in series, and a bus connection wire 825 may couple coil 823 to second bus 875. Similarly, third and fourth groups of coils 830, 840 may comprise a plurality of coils connected in series by one or more connecting wires, such as wires 834, 836, 844, and/or 846, and one or more bus connection wires 835, 845 may couple the last coil in each group to the first bus 870 and second bus 875, respectively. Although the groups of coils are each shown as comprising three coils, fewer or more coils may be connected in series. Each group of coils may also comprise a routing wire. For example, first group of coils 810 may comprise routing wire 818, second group of coils 820 may comprise routing wire 828, third group of coils 830 may comprise routing wire 838, and fourth group of coils 840 may comprise routing wire 848. In some examples, one or more of the routing wires 818, 828, 838, 848 may be configured to be routed out through a surrounding containment structure, such as main containment vessel 220 and/or upper containment vessel 250 (FIG. 2). Additionally, one or more bus routing wires, such as bus routing wires 873 and 877, may be associated with first bus 870 and second bus 875, respectively. First bus 870 and/or second bus 875 may be configured to provide a voltage source to one or more of the groups of coils. For example, first bus 870 may be configured to provide an AC voltage to first group of coils 810 via bus connection wire 815. The AC voltage may be provided to an input of coil 813. First bus 870 may be configured to supply 24 volts, or some other value. In some examples, the voltage provided by one or more of the buses may be dependent upon the number of sensing coils connected in series within any one group. For example, in order to provide 24 volts to each sensing device associated with a group of three sensing devices coupled in series, the bus may be associated with a 72 volt power supply, i.e., taking the product of the per-device voltage and the number of sensing devices in the group. Additionally, an output of coil 813 may be electrically coupled to an input of coil 812 via connecting wire 816, and similarly an output of coil 812 may be electrically coupled to an input of coil 811 via connecting wire 814. The voltage associated with first group of coils 810 may be measured and/or otherwise determined from the output of coil 810 via routing wire 818. Similarly, voltages associated with the second, third, and/or fourth groups of coils 820, 830, 840 may be measured and/or otherwise determined via routing wires 828, 838, and 848, respectively. In an example configuration where there are 78 coils in the RPI system, and each of the groups of coils comprises three coils connected in series, there may be 26 routing wires associated with the coils. Each of the 26 routing wires may be used to measure and/or determine a voltage signal, or some other type of signal, associated with the groups of coils. The number of routing wires may be further decreased by connecting more than three coils in series within one or more of the groups of coils. While the groups of coils are shown as including the same number of coils, in some examples, different numbers of coils may be connected in series in one or more of the groups of coils. FIG. 9 illustrates an example RPI system 900 configured to determine the position of a control rod operatively coupled to drive rod 675. RPI system 900 may comprise a plurality of grouped coil arrangements. A first group of coils may comprise three or more coils, such as coils 910, 930, and 950. Similarly, a second group of coils may comprise coils 920, 940, and 960. One or more additional groups of coils may also each comprise three or more coils, including coil 980 and coil 990. In some examples, half of the groups of coils may be electrically coupled to a first bus 970 and a second half of the groups of coils may be electrically coupled to a second bus 975. Additionally, the groups of coils may be coupled to the buses in an alternating or staggered arrangement. For example, the first group of coils may be electrically coupled to first bus 970 and the second group of coils may be electrically coupled to second bus 975. A first terminal 915 of first coil 910 may be electrically coupled to first bus 970 by a bus connection wire 912. Similarly, a first terminal 925 of second coil 920 may be electrically coupled to second bus 975 by a bus connection wire 924. Additionally, one or more terminals 976, 978 of the additional groups of coils including coils 980 and 990 may be electrically coupled to first bus 970 and to second bus 975, respectively. Coils associated with the first group of coils may be electrically coupled to each other in series. For example, a second terminal 918 of first coil 910 may be coupled to a first terminal 935 of coil 930 by a connecting wire 916. A second terminal 938 of third coil 930 may be coupled to a first terminal 958 of fifth coil 950 by a connecting wire 936. Similarly, one or more terminals 928, 945, 948, 965 associated with the second group of coils may be electrically coupled together by one or more wires 926, 946. Although the groups of coils are each shown as comprising three coils, fewer or more coils may be connected together. Each group of coils may also comprise a routing wire. For example, the first group of coils may comprise routing wire 952 electrically coupled to a second terminal 958 of fifth coil 950, and the second group of coils may comprise routing wire 964 electrically coupled to a second terminal 968 of sixth coil 960. Similarly, the one or more additional groups of coils may each be associated with a routing wire, such as routing wires 982, 994. In some examples, one or more of the routing wires 952, 964, 982, 994 may be configured to be routed out through a surrounding containment structure, such as main containment vessel 220 and/or upper containment vessel 250 (FIG. 2). Additionally, one or more bus routing wires, such as bus routing wires 973 and 977, may be associated with first bus 970 and second bus 975, respectively. First bus 970 and/or second bus 975 may be configured to provide a voltage source to one or more of the groups of coils. For example, first bus 970 may be configured to provide a voltage to the first group of coils via bus connection wire 912. The voltage associated with the first group of coils may be measured and/or otherwise determined via routing wire 952. Similarly, second bus 975 may be configured to provide a voltage to the second group of coils via bus connection wire 924, and the voltage associated with the second group of coils may be measured and/or otherwise determined via routing wire 964. In some examples, one or both of first bus 970 and second bus 977 may be configured to supply an AC signal to the first coil in each coil group, e.g., to coil 910 in the first coil group and to coil 920 in the second coil group. The AC signal may be associated with a bus voltage. In some examples the bus voltage may be determined based, at least in part, on the number of coils in each coil group. In examples in which each coil is associated with a particular coil voltage, such as 24 volts, the bus voltage may be determined by multiplying the coil voltage by the number of coils in the coil group. In a coil group comprising three coils, the bus voltage may be 72 volts. Additionally, the bus voltage and/or coil voltage may be measured, calculated, or otherwise determined as a root mean square (RMS) of the voltage signal. Accordingly, first bus 970 and/or second bus 975 may be configured to provide and/or supply a signal with a 72 volt RMS output, or some other voltage output. The signal may be encoded. Any two adjacent coils may be associated with a different coil group. In some examples, each coil within a coil group may be separated from each other by at least one coil associated with another coil group. Additionally, each coil may be electrically coupled to a different bus and/or power supply than the adjacent coils. Additional accuracy and sensitivity may be gained by measuring the current from a coil group, at the routing wire 952, 964, 982, 994 for example, and calculating the phase relationship to the AC voltage at the same point. The difference in the phase angle will correspond to the position of the drive rod within a coil group as a function of the coil group inductance. FIG. 10 illustrates another example RPI system 1000 configured to determine the position of a control rod operatively coupled to drive rod 675. RPI system 1000 may comprise a plurality of coils, such as coils 1010, 1020, 1030, 1040, 1050, 1060, 1080, and 1090 configured in a number of coil groups. Additionally, each coil group may be associated with a number of coils. The coils in RPI system 1000 may be configured as and/or schematically arranged into a number of portions. The number of portions may correspond to the number of coils associated with each coil group. In examples in which there are three coils associated with each coil group, the RPI system 1000 may comprise coils arranged into three portions. For example, a first or upper coil portion may be associated with a number of coils such as coils 1010, 1020, 1030, 1040, a second or intermediate coil portion may be associated with a number of coils such as coils 1050, 1060, and a third or lower coil portion may be associated with a number of coils such as coils 1080, 1090. A first group of coils may comprise a first coil, such as coil 1010, selected from the first coil portion, a second coil, such as coil 1050, selected from the second coil portion, and a third coil, such as coil 1080, selected from the third coil portion. A first terminal 1015 of coil 1010 may be electrically coupled to first bus 1070 by a bus connection wire 1012. Additionally, connecting wire 1016 may electrically couple coil 1010 to coil 1050 via a second terminal 1018 of coil 1010. Coil 1010 may be electrically coupled in series to coil 1050 and to coil 1080 by connecting wire 1016 and by connecting wire 1056, respectively. A second group of coils including coils 1020, 1060, 1090 may also be selected from the first, second, and third portions of RPI system 1000. A first terminal 1025 of coil 1020 may be electrically coupled to second bus 1075 by a bus connection wire 1024. Additionally, connecting wire 1026 may electrically couple coil 1020 to coil 1060 via a second terminal 1028 of coil 1020. Coil 1020 may be electrically coupled in series to coil 1060 and to coil 1090 by connecting wire 1026 and by connecting wire 1046, respectively. One or more additional groups of coils, such as groups including coils 1030 and 1040, may be configured similarly as the first and/or second groups of coils. For example, a third coil group associated with coil 1030 may be electrically coupled to first bus 1070 by a bus connection wire 1032 via a first terminal 1035 of coil 1030, and a fourth coil group associated with coil 1040 may be electrically coupled to second bus 1075 by a bus connection wire 1044 via a first terminal 1045 of coil 1040. All of the coils associated with any one coil group may be separated from each by a number of intervening coils from other coil groups. For example, a first coil 1010 of the first coil group may be separated from the second coil 1050 of the first coil group by at least coils 1020, 1030, and 1040. Each of the intervening coils may be associated with different coil groups. In an example RPI system associated with a total of 78 coils separated into 26 coil groups, there may be 25 intervening coils between the coil 1010 and coil 1050. Similarly, there may be 25 intervening coils between coil 1050 and coil 1080. In some examples, any two adjacent coils may be electrically coupled to a different bus and/or to a different power supply. Each group of coils may also comprise a routing wire. For example, the first group of coils may comprise routing wire 1082 electrically coupled to the third or final coil 1080 of the first group of coils, and the second group of coils may comprise routing wire 1094 electrically coupled to the third or final coil 1090 of the second group of coils. The voltage associated with the first group of coils may be measured and/or otherwise determined via routing wire 1082. Similarly, the voltage associated with the second group of coils may be measured and/or otherwise determined via routing wire 1094. Similarly, the one or more additional groups of coils may each be associated with a routing wire, such as routing wires 1052, 1064. In some examples, one or more of the routing wires 1052, 1064, 1082, 1094 may be configured to be routed out through a surrounding containment structure, such as main containment vessel 220 and/or upper containment vessel 250 (FIG. 2). Additionally, one or more bus routing wires, such as bus routing wires 1073 and 1077, may be associated with first bus 1070 and second bus 1075, respectively. By arranging the coils in a number of portions and by selecting one coil from each portion to belong to a coil group, the coils associated with a single portion of RPI system 1000 may all be directly coupled to one or more buses 1070, 1075. For example, coils associated with the first or upper coil portion, such as coils 1010, 1020, 1030, 1040 may all be directly coupled to one or more buses 1070, 1075. Additionally, all the coils in the intermediate and lower coil portions, such as coils 1050, 1060, 1080, 1090, may be may be indirectly coupled to one or more of buses 1070, 1075. On the other hand, coils associated with the lower coil portion, such as coils 1080, 1090, may all be directly coupled to routing wires, such as routing wires 1082, 1094, and all the coils in the intermediate and upper coil portions may be may be indirectly coupled to the routing wires. FIGS. 6-10 illustrate various example configurations for electrically coupling coils as a number of coil groups, and other RPI systems may be configured with different coil arrangements and/or groupings. For example, a number of adjacent coils may be grouped together instead of having intervening coils from different coil groups interspersed between the coils in the particular coil group. Additionally, two coils within a particular coil group may be separated by any number of intervening coils from other coils groups. For example the number of intervening coils may range from between one to twenty five coils for an RPI system having 78 coils. In some examples, sensing devices other than sensing coils may be used in the RPI system. For example, one or more of the sensing devices may comprise proximity sensors, magnetic sensors, Hall Effect sensors, other types of sensing devices, or any combination thereof. FIG. 11 illustrates a simplified schematic diagram for an example RPI system 1100. RPI system 1100 may comprise a number of sensing devices, configured to determine the position of a control rod operatively coupled to a drive rod. The control rod may be configured to be alternatively withdrawn from and inserted into a reactor core. A number of sensing devices may be linearly arranged along a path of the drive rod. An end of the drive rod may pass by or through one or more of the sensing devices in response to the withdrawal of the control rod from the reactor core. In some examples, the drive rod may be movably inserted within or by one or more of a plurality of sensing devices, such as sensing devices 1111, 1112, 1113, 1121, 1122, and 1123. Additionally, the plurality of sensing devices may be schematically arranged into a plurality of groups of sensing devices. Each group may comprise two or more of sensing devices electrically coupled together in series. A first group of sensing devices 1110 may comprise sensing devices 1111, 1112, and 1113, and a second group of sensing devices 1120 may comprise sensing devices 1121, 1122, and 1123. In some examples, sensing devices 1111, 1112, and 1113 be electrically coupled together in series. Additionally sensing devices 1121, 1122, and 1123 may be electrically coupled together in series. RPI system 1100 may be configured similarly as the example RPI system 900 illustrated in FIG. 9. For example, the first sensing device 1121 of the second group of sensing devices 1120 may be linearly arranged between the first sensing device 1111 and the second sensing device 1112 of the first group of sensing devices 1110. Additionally, the second sensing device 1112 of the first group of sensing devices 1110 may be linearly arranged between the first sensing device 1121 and the second sensing device 1122 of the second group of sensing devices 1120. In this manner, the sensing devices of one group of sensing devices may be interleaved and/or separated by intervening sensing devices associated with one or more other groups of sensing devices. In still other examples, RPI system 1100 may be configured similarly as the example RPI system 1000 illustrated in FIG. 10. First group of sensing devices 1110 may be electrically coupled to a bus, such as a first bus 1170, via a terminal 1118 of sensing device 1113. Additionally, sensing device 1111 may comprise a terminal 1115 electrically coupled to a routing wire 1102. Second group of coils 1120 may be electrically coupled to a bus, such as a second bus 1175, via a terminal 1128 of sensing device 1123, and sensing device 1121 may comprise a terminal 1125 electrically coupled to a routing wire 1124. Additionally, first and second buses 1170 and 1175 may be associated with bus routing wires 1173 and 1177 respectively. First group of sensing devices 1110, second group of sensing devices 1120, first bus 1170, and second bus 1175 may all be at least partially housed within a containment structure 1150. Containment structure 1150 may be sealed to the outside environment. One or more penetrations, such as penetrations 1151, 1152, 1153, and 1157, may be configured to allow routing wires 1102, 1124 and/or bus routing wires 1173, 1177 to be routed through containment structure 1150. In some examples, one or more routing wires may be routed through the same penetration. Additionally, RPI system 1100 may comprise a RPI monitoring device 1190. RPI monitoring device 1190 may be located outside of containment structure 1150. One or more of the routing wires 1102, 1124 and/or bus routing wires 1173, 1177 may be routed to or into RPI monitoring device 1190. RPI monitoring device 1190 may be electrically coupled to each group of sensing devices by a routing wire. RPI monitoring device 1190 may be located remotely from containment structure 1150, such as in an operations room or control center of a nuclear power plant. Additionally, the reactor core may be housed in a reactor pressure vessel contained within the containment vessel, such that the groups of sensing devices may be located in a containment region formed between the reactor pressure vessel and the containment vessel. The total number of routing wires associated with the groups of sensing devices that are routed out of containment structure 1150, such as routing wires 1115 and 1124, may be less than half of the number of sensing devices. The groups of sensing devices may comprise sensing coils configured with first and second terminals that electrically couple the sensing coils in series. A first terminal of a first sensing coil, such as terminal 1115, may be electrically coupled to RPI monitoring device 1190 via a routing wire, such as routing wire 1115. Similarly, a second terminal of the first sensing coil, such as terminal, may be electrically coupled to a first terminal of a second sensing coil. Additionally, a second terminal of the second sensing coil may be electrically coupled to a first terminal of a third sensing coil. A second terminal of the third or final sensing coil, such as terminal 1118, may be electrically coupled to at least one of the one or more buses, such as first bus 1170. In some examples, the total number of routing wires associated with the groups of sensing devices that are routed to RPI monitoring device 1190 may be approximately one third of the number of sensing devices. RPI monitoring device 1190 may be configured to measure and/or otherwise determine the position of a control rod based on one or more signals received on routing wires 1102, 1124 and/or on bus routing wires 1173, 1177. RPI monitoring device 1190 may comprise one or more circuit components, such as a first circuit component 1130 and/or a second circuit component 1135. In some examples, first circuit component 1130 and/or second circuit component 1135 may comprise one or more resistors, such as current sensing resistors. First circuit component 1130 may be electrically coupled to first group of sensing devices 1110 via routing wire 1102. Similarly, second circuit component 1135 may be electrically coupled to second group of sensing devices 1120 via routing wire 1124. RPI monitoring device 1190 may further comprise one or more power supplies, such as a first power supply 1180 and/or a second power supply 1185. First bus 1170 may be electrically coupled to first power supply 1180 via bus routing wire 1173. Similarly, second bus 1175 may be electrically coupled to second power supply 1185 via bus routing wire 1177. First circuit component 1130 may be electrically coupled to first power supply 1180 and second circuit component 1135 may be electrically coupled to second power supply 1185. Additionally, first circuit component 1130, second circuit component 1135, first power supply 1180, and/or second power supply 1185 may be located outside of containment structure 1150. A comparator 1140 may be configured to compare an electrical property, such as a current or a voltage, associated with one or both of the first circuit component 1130 and the second circuit component 1135. For example, first circuit component 1130 may comprise a first resistor, and second circuit component 1135 may comprise a second resistor. Comparator 1140 may be configured to compare a first current across the first resistor to a second current across the second resistor. The electrical property may be compared based, at least in part, on input received over input lines 1142 and 1144 which couple first circuit component 1130 and second circuit component 1135 to comparator 1140. Additionally, comparator 1140 may be configured to output rod position information on output line 1145. RPI monitoring device 1190 may be configured to determine a difference between signals associated with two or more sensing devices and/or groups of sensing devices, such as first group of sensing devices 1110 and second group of sensing devices 1120. In some examples, RPI monitoring device 1190 may be configured to determine a difference 1160 in output voltage between the two or more groups of sensing devices based, at least in part, on differences in the electrical property of the signals transmitted over input lines 1142, 1144. In example RPI systems where each group comprises more than two sensing devices, the signals transmitted over input lines 1142 and/or 1144 may be evaluated to determine which sensing device within the group of sensing devices is proximate to the end of the drive rod. The signal transmitted over input line 1142 may be associated with a range of values. In some examples, the range of values may comprise step values. A first value may be associated with a position of drive rod proximate to first sensing device 1111, a second value may be associated with a position of drive rod proximate to second sensing device 1112, and a third value may be associated with a position of drive rod proximate to third sensing device 1113. In some examples, the value associated with the signal may indicate that the drive rod is generally located between two sensing devices. FIG. 12 illustrates a simplified schematic diagram for another RPI monitoring device 1290. RPI monitoring device 1290 may include an RPI encoder 1210 electrically coupled to one or more of the input lines from the groups of sensing devices, such as input lines 1142, 1144. The RPI encoder 1210 may be configured to determine a position of the control rod based, at least in part, on the signal output from the one or more input lines 1142, 1144. The RPI encoder 1210 may measure an electrical property present on an input line. The electrical property may comprise an AC voltage that has been phase shifted relative to the input line signal due to the inductance of its associated coil group. A second electrical property may comprise an AC current that has been phase shifted relative to the input line signal due to the inductance of its associated coil group. The measured value of the difference in phase between the AC voltage signal and the AC current signal may correspond to a sensing device and/or to a group of sensing devices associated with the position of the drive rod. The RPI encoder 1210 may determine which sensing device an upper end of the drive rod is proximate to based, at least in part, on a measured value of the electrical property. In some examples, the RPI encoder 1210 may combine the measured values of the electrical property for each input line in an RPI system, such as by summing the measured values. The RPI encoder 1210 may determine which coil in the RPI system the upper end of the drive rod is proximate to based, at least in part, on the combined measured values. FIG. 13 illustrates an example process 1300 for indicating a control rod position. At operation 1310, a control rod may be withdrawn from and/or moved relative to a reactor core. The control rod may be operably coupled to a drive rod of a control rod drive mechanism. At operation 1320, the drive rod may be configured to move relative to a number of sensing devices associated with a rod position indicator (RPI) apparatus in response to withdrawing the control rod. The number of sensing devices may be arranged along a path of the drive rod. In some examples, the number of sensing devices may be linearly arranged along the path of the drive rod. Additionally, the sensing devices may be arranged into a plurality of groups, such that each group may comprise two or more of the sensing devices electrically coupled together in series. In some examples, each group may consist of three sensing devices coupled together in series. The RPI apparatus may be electrically coupled to each group of sensing devices by a separate routing wire. At operation 1330, a change in electrical property of a first sensing device may be detected or otherwise determined based, at least in part, on an end of the drive rod located in proximity to the first sensing device. The first sensing device may be associated with a first group of sensing devices comprising the first sensing device and a third sensing device electrically coupled together in series. At operation 1340, a first signal associated with the change in electrical property of the first sensing device may be received at the RPI apparatus. In some examples, the RPI apparatus may comprise a first circuit component electrically coupled to the first group of sensing devices. The first signal may be received from the first circuit component and/or from the first group of sensing devices. At operation 1350, a change in electrical property of a second sensing device may be detected or otherwise determined based, at least in part, on the end of the drive rod located in proximity to the second sensing device. The second sensing device may be associated with a second group of sensing devices comprising the second sensing device and a fourth sensing device electrically coupled together in series. At operation 1360, a second signal associated with the change in electrical property of the second sensing device may be received at the RPI apparatus. In some examples, the RPI apparatus may comprise a second circuit component electrically coupled to the second group of sensing devices. The second signal may be received from second circuit component and/or from the second group of sensing devices. The second sensing device associated with the second group of sensing devices may be linearly arranged between the first sensing device and the third sensing device of the first group of sensing devices. Additionally, the third sensing device associated with the first group of sensing devices may be linearly arranged between the second sensing device and the fourth sensing device of the second group of sensing devices. At operation 1370, the first signal may be compared to the second signal. In some examples, the first circuit component may comprise a first resistor, and the second circuit component may comprise a second resistor. The first signal may comprise and/or otherwise be associated with a first current across the first resistor. Similarly, the second signal may comprise and/or otherwise be associated with a second current across the second resistor. In still other examples, a RMS voltage value associated with the first circuit component may be compared to a RMS voltage value associated with the second circuit component. At operation 1380, the position of the drive rod relative to the number of sensing devices may be determined based, at least in part, on the comparison of the first signal to the second signal. At operation 1390, the position of the control rod may be indicated in response to determining the relative position of the drive rod. The drive rod and the groups of sensing devices may all be located with a containment structure. The RPI apparatus may be located outside of the containment structure. In some examples, the RPI apparatus may be electrically coupled to each group of sensing devices by a single routing wire, and the total number of routing wires associated with the groups of sensing devices that are routed out of the containment structure may be less than half of the number of sensing devices. In some examples, the total number of routing wires associated with the groups of sensing devices that are routed out of the containment structure may be approximately one third the number of sensing devices. Although the examples provided herein have primarily described a pressurized water reactor and/or a light water reactor, it should be apparent to one skilled in the art that the examples may be applied to other types of power systems. For example, the examples or variations thereof may also be made operable with a boiling water reactor, sodium liquid metal reactor, gas cooled reactor, pebble-bed reactor, and/or other types of reactor designs. Some or all of the examples provided herein may be used to measure the drive rod position for one or more types of CRDM assemblies that may be different than that described, for example CRDM assemblies that may comprise a lead screw and roller nut type of drive or a hydraulic drive, such as for a boiling water reactor. Additionally, one or more of the examples may be used to measure the position of other types of drive rods in sealed enclosures that may also utilize a reduced number of electrical connections. For example, one or more of the examples may be used to measure the position of a piston of a hydraulic cylinder It should be noted that examples are not limited to any particular type of reactor cooling mechanism, nor to any particular type of fuel employed to produce heat within or associated with a nuclear reaction. Any rates and values described herein are provided by way of example only. Other rates and values may be determined through experimentation such as by construction of full scale or scaled models of a nuclear reactor system. Having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail. We claim all modifications and variations coming within the spirit and scope of the following claims.
	summary
	claims	1. A radiation-shielding assembly for radioactive material, the assembly comprising:a body having a cavity defined therein for receiving radioactive material, the body having first and second openings into the cavity, the first opening being sized smaller than the second opening, and the body being constructed to limit escape of radiation from the cavity through the body;a first base releasably attachable to the body generally at the second opening thereof; anda second base releasably attachable to the body generally at the second opening thereof when the first base is not releasably attached to the body, wherein the first base has a length and a weight, and wherein the second base has at least one of a shorter length and a lighter weight than the first base;the first base including first and second closure surfaces, wherein the first base is releasably attachable to the body in a first orientation in which the first closure surface is positioned generally at the second opening and faces inward of the cavity at a first distance from the first opening, and wherein the first base is releasably attachable to the body in a second orientation in which the second closure surface is positioned generally at the second opening and faces inward of the cavity at a second distance from the first opening, the first distance being different from the second distance. 2. The assembly of claim 1, wherein the body and first base together have a first center of gravity when the first base is releasably attached to the body, wherein the body and second base together have a second center of gravity when the second base is releasably attached to the body, and wherein the first center of gravity is closer to the first opening than the second center of gravity. 3. The assembly of claim 1, wherein the first base comprises:a radiation shield adapted to limit passage of radiation therethrough and positioned generally at the second opening when the first base is releasably attached to the body; andan extension element connected to the radiation shield and configured to extend away from the body when the first base is attached thereto. 4. The assembly of claim 3, wherein the extension element is constructed of a material that is substantially transparent to radiation. 5. The assembly of claim 1, wherein the first base comprises an extension element having first and second spaced apart ends, a first radiation shield connected to the first end of the extension element and adapted to limit escape of radiation from the cavity through the second opening when the first base is attached to the body in the first orientation, and a second radiation shield connected to the second end of the extension element and adapted to limit escape of radiation from the cavity through the second opening when the first base is connected to the body in the second orientation. 6. The assembly of claim 5, wherein the extension element is substantially transparent to radiation. 7. The assembly of claim 5, wherein the extension element and body are constructed of different materials, the material of the extension element being less dense than the material of the body. 8. The assembly of claim 1, wherein the second base comprises first and second closure surfaces, wherein the second base is releasably attachable to the body in a first orientation relative to the body in which the first closure surface is positioned generally at the second opening and faces inward of the cavity at a first distance from the first opening, and wherein the second base is releasably attachable to the body in a second orientation relative to the body in which the second closure surface is positioned generally at the second opening and faces inward of the cavity at a second distance from the first opening, the first distance being different from the second distance. 9. The assembly of claim 8, wherein the second base comprises a single radiation shield. 10. The assembly of claim 8, wherein the second base is constructed for threaded attachment to the body in the first and second orientations. 11. The assembly of claim 1, further comprising:a cap constructed for releasable engagement with the body generally at the first opening thereof. 12. The assembly of claim 1, wherein at least one of the body, the first base, and the second base comprises tungsten-impregnated plastic. 13. The assembly of claim 1, wherein at least one of the first and second bases is constructed to limit escape of radiation from the cavity through the second opening of the body when the respective base is attached to the body. 14. The assembly of claim 1 in combination with the container of radioactive material. 15. A radiation-shielding assembly for radioactive material, the assembly comprising:a body having a cavity defined therein for receiving radioactive material, the body having first and second openings into the cavity, the first opening being sized smaller than the second opening, and the body being constructed to limit escape of radiation from the cavity through the body;a first base releasably attachable to the body generally at the second opening thereof; anda second base releasably attachable to the body generally at the second opening thereof when the first base is not releasably attached to the body, wherein the first base has a length and a weight, and wherein the second base has at least one of a shorter length and a lighter weight than the first base;the second base including first and second closure surfaces, wherein the second base is releasably attachable to the body in a first orientation relative to the body in which the first closure surface is positioned generally at the second opening and faces inward of the cavity at a first distance from the first opening, and wherein the second base is releasably attachable to the body in a second orientation relative to the body in which the second closure surface is positioned generally at the second opening and faces inward of the cavity at a second distance from the first opening, the first distance being different from the second distance. 16. The assembly of claim 15, wherein the second base comprises a single radiation shield. 17. The assembly of claim 15, wherein the second base is constructed for threaded attachment to the body in the first and second orientations. 18. The assembly of claim 15, further comprising:a cap constructed for releasable engagement with the body generally at the first opening thereof. 19. The assembly of claim 15, wherein at least one of the first and second bases is constructed to limit escape of radiation from the cavity through the second opening of the body when the respective base is attached to the body. 20. The assembly of claim 15 in combination with the container of radioactive material. 21. A radiation-shielding assembly for radioactive material, the assembly comprising:a body having a cavity defined therein for receiving a first container of radioactive material, the body having first and second openings into the cavity, the first opening being sized smaller than the second opening, and the body being constructed to limit escape of radiation from the cavity through the body;a first base releasably attachable to the body generally at the second opening thereof; anda second base releasably attachable to the body generally at the second opening thereof when the first base is not releasably attached to the body, wherein the first base has a length, and wherein the second base has a shorter length than the first base to accommodate a second container;the body and first base together having a first center of gravity when the first base is releasably attached to the body, the body and second base together having a second center of gravity when the second base is releasably attached to the body, and wherein the first center of gravity is closer to the first opening than the second center of gravity. 22. The assembly of claim 21 in combination with the container of radioactive material.
050698656	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to fabrication of nuclear fuel rods and, more particularly, is concerned with a method of forming a gripper cavity in a fuel rod end plug. 2. Description of the Prior Art In a typical nuclear reactor, such as a pressurized water type, the reactor core includes a large number of fuel assemblies each of which is composed of top and bottom nozzles with a plurality of elongated transversely spaced guide thimbles extending longitudinally between the nozzles and a plurality of transverse support grids axially spaced along and attached to the guide thimbles. Also, each fuel assembly is composed of a plurality of elongated fuel elements or rods transversely spaced apart from one another and from the guide thimbles and supported by the transverse grids between the top and bottom nozzles. The fuel rods each contain fissile material and are grouped together in an array which is organized so as to provide a neutron flux in the core sufficient to support a high rate of nuclear fission and thus the release of a large amount of energy in the form of heat. A liquid coolant is pumped upwardly through the core in order to extract some of the heat generated in the core for the production of useful work. Each fuel rod includes nuclear fuel pellets and the opposite ends of the rod are closed by upper and lower end plugs to hermetically seal the rod. A cavity is formed in the lower end plug as part of the forming of the end plug. Subsequently, a groove is formed in the cavity by a secondary machining operation. The groove is provided in order to assist in assembling of the fuel assembly by insertion of the fuel rods into the grids of the fuel assembly. The groove in the cavity enables a gripping mechanism, such as disclosed in U.S. Pat. No. 4,966,745, assigned to the same assignee as the subject invention, to enter the lower end plug cavity, expand into the groove, and then pull the fuel rod at lower end plug through the grids of the fuel assembly already attached to the guide thimbles. Several problems are associated with the current approach of machining the groove in the cavity. First, attaining the desired cavity and groove configuration requires an excessive amount of machining at a cost higher than the material cost of the bottom end plug itself. About one-half of the machining cost goes toward forming the groove in the cavity. Second, the fabrication of the groove is currently performed by an operator and thus depends on the operator doing it properly. However, occasionally the groove is left out completely due to operator oversight which creates fuel rod loading problems at final assembly. Third, sometimes the gripper mechanism shears out the material in the end plug due to high loading force and stress on the end plug. Consequently, a need exists for a different approach to fabrication of the cavity and groove in the bottom end plug for the nuclear fuel rod so as to avoid the problems associated with the current techniques. SUMMARY OF THE INVENTION The present invention provides an end plug cavity forming method designed to satisfy the aforementioned needs. First, the end plug cavity forming method of the present invention employs roll-forming steps which significantly reduce the amount of machining required and thereby the associated cost. Second, the method of the invention is an automatic unattended operation which eliminates the possibility that the groove will be omitted due to operator oversight. Third, the method of the invention involves cold forming of the tip of the end plug which improves the strength of the gripper cavity and makes the end plug more resistant to damage during assembly loading operation. Accordingly, the present invention is directed to a method of forming a gripper cavity in a nuclear fuel rod end plug. The cavity forming method comprises the steps of: (a) providing an end plug blank having an internal bore of substantially uniform diameter that opens at an annular outer rim on the end plug blank; (b) cold forming the end plug blank to produce an intermediate end plug in which the annular outer rim is transformed into a conical outer rim having a rounded internal surface that defines an inlet opening to the internal bore of a diameter less than that of the internal bore; and (c) removing an external layer of material from the intermediate end plug and an internal layer of material from the rounded internal surface of the conical outer rim to produce a finished end plug having an internal gripper cavity composed of the internal bore and a cylindrical internal surface defining the inlet opening to the internal bore and of smaller diameter than the internal bore. The cold forming includes rotating the end plug blank about a longitudinal axis, and concurrently advancing a plurality of rollers into contact with the annular outer rim on the end plug blank until the annular outer rim is transformed into the conical outer rim. These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
	summary
	description	The present invention relates to a terminal end-piece for a nuclear reactor fuel assembly, the assembly comprising fuel rods and a skeleton for supporting the fuel rods, the fuel rods extending in a longitudinal direction and being arranged at the nodes of a substantially regular network, the support skeleton comprising two terminal end-pieces and elements for connecting the terminal end-pieces, the fuel rods being arranged longitudinally between the terminal end-pieces. The invention is used in particular for constructing bottom end-pieces of fuel assemblies for pressurised water nuclear reactors (PWR). EP-537 044 describes a bottom end-piece for such an assembly. That end-piece comprises a horizontal wall which is provided with feet for support on the lower plate of a nuclear reactor core. The elements for connecting the bottom end-piece to the top end-piece are constituted by guide tubes. Those guide tubes are fixed to the horizontal wall of the end-piece. The horizontal wall comprises reinforcement ribs under the lower surface thereof. In each zone of the horizontal wall delimited between the reinforcement ribs, holes for the passage of coolant water are provided so that the horizontal wall constitutes an anti-debris filter. The coolant water flows in the core of the reactor vertically in an upward direction. More precisely, the water is introduced into the core through the lower core plate, then passes through the bottom end-piece by way of the above-mentioned holes before coming into contact with the outer surfaces of the fuel rods. The water flows in the core at a very high ascending rate. It has been found, during operation of the core, that the fuel rods, and in particular the lower ends thereof, were subjected to vibrations which are liable to damage them. In greater detail, phenomena involving friction or “fretting” are liable to occur in particular between the lower grid of the support skeleton and the outer claddings of the fuel rods. These friction phenomena may lead to damage to outer claddings which may bring about a release of fission gas or product in the water of the primary circuit. An objective of the invention is to overcome this problem by limiting the vibrations of the fuel rods of assemblies for a nuclear reactor. To that end, the invention relates to a terminal end-piece for a nuclear reactor fuel assembly, the assembly comprising fuel rods and a skeleton for supporting the fuel rods, the fuel rods extending in a longitudinal direction and being arranged at the nodes of a substantially regular network, the support skeleton comprising two terminal end-pieces and elements for connecting the terminal end-pieces, the fuel rods being arranged longitudinally between the terminal end-pieces, characterised in that the end-piece comprises noses for orientating the flow of a coolant fluid of the reactor along the adjacent longitudinal ends of the fuel rods, the noses being arranged in nodes of the substantially regular network in order to be positioned in a longitudinal continuation of at least some of the fuel rods and/or at least some of the connection elements of the support skeleton. According to specific embodiments, the end-piece may comprise one or more of the following features, taken in isolation or according to any technically possible combination: the noses converge in a direction which is intended to be orientated towards the outer side of the fuel assembly, at least some of the noses belong to members for fixing the terminal end-piece to connection elements of the support skeleton or fuel rods, the fixing members are screws, the end-piece comprises an arrangement for laterally maintaining adjacent longitudinal ends of the fuel rods, which the maintaining arrangement is arranged in nodes of the substantially regular network, the maintaining arrangement comprises housings for receiving the adjacent longitudinal ends of the fuel rods, the maintaining arrangement constitutes an arrangement for longitudinally securing the adjacent longitudinal ends of the fuel rods relative to the terminal end piece, the end-piece comprises two components for clamping between them the adjacent longitudinal ends of the fuel rods, the end-piece comprises an anti-debris filter, one of the components constitutes the anti-debris filter, the end-piece constitutes a bottom end-piece and the end-piece comprises feet for support on a lower plate of the nuclear reactor core. The invention further relates to a fuel assembly for a nuclear reactor, the assembly comprising fuel rods and a skeleton for supporting the fuel rods, the fuel rods extending in a longitudinal direction and being arranged at the nodes of a substantially regular network, the support skeleton comprising two terminal end-pieces and elements for connecting the terminal end-pieces, the fuel rods being arranged longitudinally between the terminal end-pieces, characterised in that at least one end-piece is an end-piece as defined above. According to specific embodiments, the assembly may comprise one or more of the following features, taken in isolation or according to any technically possible combination: the end-piece comprises an arrangement for laterally maintaining adjacent longitudinal ends of the fuel rods, which the maintaining arrangement is arranged in nodes of the substantially regular network, the maintaining arrangement comprises housings which receive the adjacent longitudinal ends of the fuel rods, the maintaining arrangement constitutes an arrangement for longitudinally securing the adjacent longitudinal ends of the fuel rods relative to the terminal end-piece, the end-piece comprises two components which clamp between them the adjacent longitudinal ends of the fuel rods, the longitudinal securing arrangement comprises projections that are provided on the end-piece and rings that are provided at the adjacent longitudinal ends of the fuel rods and which are fitted to those projections, the rings comprise relief portions for abutment against one of the components, the adjacent longitudinal ends of the fuel rods comprise widened feet which are clamped between the two components, the adjacent longitudinal ends of the fuel rods are expansion-rolled on the end-piece, the longitudinal securing arrangement comprises screws that abut the end-piece and which are engaged in the adjacent longitudinal ends of the fuel rods and the longitudinal securing arrangement is, for example, snap-fitting. In order to illustrate the context of the invention, FIG. 1 schematically illustrates a nuclear fuel assembly 1 for a pressurized water reactor. Therefore, the water fulfils in that case a coolant and moderating function, for example, slowing down the neutrons produced by the nuclear fuel. The assembly 1 extends vertically and in a rectilinear manner in a longitudinal direction A. Conventionally, the assembly 1 principally comprises nuclear fuel rods 3 and a structure or skeleton 5 for supporting the rods 3. The support skeleton 5 conventionally comprises: a bottom end-piece 7 and a top end-piece 9 that are arranged at the longitudinal ends of the assembly 1, guide tubes 11 which are intended to receive the rods of an assembly (not illustrated) for controlling and stopping the nuclear reactor and grids 13 for maintaining the rods 3. The end-pieces 7 and 9 are fixed to the longitudinal ends of the guide tubes 11. The rods 3 extend vertically between the end-pieces 7 and 9. The rods 3 are arranged at the nodes of a substantially regular network having a square base, where they are maintained by the grids 13. Some of the nodes of the network are occupied by the guide tubes 11 and optionally by an instrumentation tube 14 which is visible at the centre of FIG. 2. In FIG. 2, the rods 3 are shown with dashed lines, the guide tubes 11 are shown with solid lines and the instrumentation tube 14 is shown using a solid black circle. The grids 13 conventionally comprise sets of intersecting plates 15 which together delimit cells which are centred on the nodes of the regular network. Most of the cells are intended to receive a fuel rod 3. 24 cells each receive a guide tube 11 and the central cell receives the instrumentation tube 14. In the example of FIGS. 1 and 2, the maintenance grids 13 comprise 17 cells per side and the regular network comprises the same number of nodes per side. In other variants, the number of cells and nodes per side may be different, for example, in the order of 14×14 or 15×15. Each rod 3 conventionally comprises an outer cladding 17 which is closed by a lower plug 19 and an upper plug 21 and which contains the nuclear fuel. These are, for example, stacked pellets of fuel, the pellets being supported on the lower plug 19. A helical maintenance spring (not illustrated) may be arranged in the cladding 11 between the upper pellet and the upper plug 21. FIGS. 3 to 7 illustrate a bottom end-piece 7 according to the invention that may be fitted to an assembly 1 as described with reference to FIGS. 1 and 2. The maintenance grids 13 are grids such as those described in documents U.S. Pat. No. 6,542,567 and EP-925 589. In some variants, the end-piece 1 may further be fitted to assemblies which are different from that described above and/or which comprise different maintenance grids. The end-piece 7 comprises a horizontal wall 23 and feet 25 that extend the wall 23 downwards in order to be supported on the lower plate of the core of the reactor. The wall 23 is generally of planar parallelepipedal form and the feet 25 are each arranged at a corner of the wall 23. The wall 23 comprises a lower member 29 and an upper plate 31 which covers the member 29. The lower member 29 comprises a plurality of units 33 which are arranged at the nodes of the same network as the fuel rods 3, the guide tubes 11 and the instrumentation tube 14. In this manner, as is visible in FIG. 3, the member 29 comprises 17×17 units 33 of cylindrical shape. Therefore, each unit 33 is located longitudinally below a fuel rod 3, a guide tube 11 or the instrumentation tube 14, if the assembly 1 comprises them. The units 33 are connected to each other by reinforcement ribs 37 which form a grid-like square around the lower member 29. The units 33 that are arranged under the fuel rods 3, have a diameter substantially corresponding to the outer diameter of the rods 3 and are extended downwards by noses 39. Those noses 39 are substantially of ogive-like forms converging downwards. Those noses 39 are integrally formed with the respective units 33. As provided in FIGS. 3 and 6, the units 33 arranged below the guide tubes 11 and the instrumentation tube 14 do not comprise integrated noses 39, but are instead perforated by vertical holes 41. For each unit 33 arranged under a guide tube 11, the hole 41 is a hole for receiving the shank of a screw 43 for fixing the end-piece 7 to the relevant guide tube 11. It will be appreciated that the head 45 of the screw 43 is substantially of ogive-like form and also constitutes a nose 39 which is arranged under the respective unit 33. It should be noted that the screws 43 have not been illustrated in FIG. 3 for clarity. The hole 41 of the central unit 33 that is arranged under the instrumentation tube 14 is itself left free in order to allow the introduction of the probe of the instrumentation tube 14. In this manner, the lower member 29 of the end-piece 7 has a network of noses 39 that is similar to that of the fuel rods 3 and the guide tubes 11. That network is interrupted only in the region of the instrumentation tube 14. In some variants, the network may also be interrupted locally in the region of that tube 14 in a more significant manner. In those variants, however, the majority of the rods 3 remain arranged above noses 39. The units 33 that are arranged below the fuel rods 3 further have blind holes 47 which open in the upper surface of the lower member 29. Those holes 47 have upper portions 49 which diverge upwards. As illustrated in FIGS. 5 and 6, the upper plate 31 comprises rings 51 that are arranged at the nodes of the same substantially regular network as the units 33. The internal passages 52 of the rings 51 arranged below the fuel rods 3 have upper portions 53 which diverge upwards and substantially cylindrical lower portions 55 that are arranged in a continuation of the upper divergent portions 49 of the blind holes 47. The outer diameter of those rings 51 is substantially equal to that of the rods 3. The internal passages 52 of the rings 51 arranged under the guide tubes 11 and the instrumentation tube 14 are, for example, of cylindrical form. The outer diameter of those rings 51 is substantially equal to that of the guide tubes 11 and the instrumentation tube 14. The rings 51 are connected to each other by reinforcement ribs 57 that are arranged, for example, in grid-like form similar to that of the ribs 37 of the lower member 29. When the upper plate 31 covers the lower member 29 of the end-piece 7, as can be seen in FIGS. 5 and 6, the ribs 57 are arranged above the ribs 37 of the member 29, the rings 51 are arranged above the units 33. Therefore, there is longitudinal continuity between the member 29 and the plate 31. Plates 59, which are finer than the ribs 57, extend between the rings 51 and the ribs 57 in order to delimit, in the plate 31, holes 61 for the passage and filtration of the coolant water. In the example illustrated, the plates 59 are arranged in grid-like form. In this manner, the upper plate 31 forms an anti-debris filter. As illustrated in greater detail in FIGS. 5 and 6, the shanks 62 of the screws 43 for fixing the guide tubes 11 extend through the corresponding holes 41 and are engaged in lower plugs 63 that are fixedly joined to the guide tubes 11. The plugs 63 are then supported on the upper plate 31 and the heads 45 of the screws 43 abut under the lower member 29. The upper plate 31 and the lower member 29 adjoin each other and the end-piece 7 is fixedly joined to the remainder of the support skeleton 5. As is visible in FIG. 7, the feet 25 have, for example, been fixed to the corners of the lower member 29 by fixing screws 65. It will be appreciated that, in FIG. 7, the unit network 33 has been illustrated only partially and the structure thereof has not been shown in detail. The passages 52 of the rings 51 arranged under the fuel rods 3 and the blind holes 47 of the units 33 arranged below form housings 67 for receiving the lower plugs 19 of the fuel rods 3. In the example illustrated in FIGS. 3 to 7, the lower plugs 19 are supported on the upper divergent portions 53 of those passages 67 via regions of complementary shape. The rods 3 are thus all maintained laterally via their lower ends relative to the bottom end-piece 7. The upper ends of the rods 3 are, for example, free as in the prior art and are not maintained by the top end-piece 9. The presence of the noses 39, which are positioned in a continuation of the rods 3 and the guide tubes 11, allows the flow paths to be orientated substantially vertically along the lower ends of the rods 3 and therefore the lateral rates of flow of the water to be reduced. The vibrations of the lower ends of the rods 3 are thereby reduced during operation of the reactor. The risks of vibration of the rods 3 are still further reduced because the lower ends of the rods 3 are laterally maintained by the end-piece 7 itself. In this manner, the vibrations of the rods 3 are limited up to such a point that it is possible to dispense with the lower maintenance grid 13. The risks of damage owing to fretting of the claddings 17 of the fuel rods 3 are therefore limited. It will be appreciated that the end-piece 7 further has good transparency with respect to the flow of water and therefore does not bring about any great pressure drop. In general terms, forms other than ogive-like forms may be envisaged for the noses 39 for longitudinally orientating the flow in the region of the lower ends of the rods 3. Thus, these may be in particular forms which converge towards the bottom, such as conical forms. Furthermore, the density of the noses 39 may be less than in the example described above, so long as the majority of the rods 3 are arranged above noses 39. Typically, the bottom end-piece 7 may be constructed from stainless steel or a zirconium alloy. It can be constructed by any conventional method. In this manner, the member 29 and the plate 31 can be constructed either by moulding or by a method using abrasive jets of water at a very high pressure (several thousands of bar), the water being able to be loaded with abrasive particles. As illustrated by the variant of FIG. 8, the horizontal wall 23 of the bottom end-piece 7 is not necessarily constituted by two portions. Thus, in this variant, the anti-debris filter is integrated in the member 29, that is to say that the plates 59 extend between the reinforcement ribs 37. In the variant of FIG. 8, it will also be appreciated that the feet 25 are, similarly to the plates 59, integrally formed with the member 29. The bottom end-piece 7 is constructed in one piece. It will also be appreciated that noses 39 arranged in a network substantially corresponding to that of the rods 3 can be used irrespective of the presence on the end-piece 7 of an arrangement for maintaining the lower ends of the rods 3. Conversely, the maintenance of the rods 3 by the bottom end-piece 7 may be more extensive and may include longitudinal securing, as illustrated by the second embodiment of the invention. The first variant of this embodiment, illustrated in FIG. 9, differs from that of FIGS. 1 to 7 principally in that the units 33 arranged longitudinally below the fuel rods 3 are extended upwards by projections 71 which are bordered by circular grooves 73. The lower plugs 19 of the rods 3 are extended downwards by substantially cylindrical rings 75. Those rings 75 are split in order to have resiliently deformable tongues 77. Each ring 75 is deformed in order to have a curved protuberance constituting a circular enlargement 79. The inner diameter of the ring 75 is slightly smaller than the outer diameter of the projections 71. In order to assemble the fuel rods 3 at the bottom end-piece 7, it is necessary to proceed as illustrated by the left-hand portion of FIG. 9. The upper plate 31 has been fitted on the fuel rods 3 beforehand by passing the upper ends of the fuel rods 3 into the internal passages 52 of the rings 51. Subsequently, the rings 75 are fitted on the projections 71, as indicated by the arrow 81 in the left-hand portion of FIG. 9. During that fitting operation, the tongues 77 are slightly resiliently deformed in a laterally outward direction. Next, the upper plate 31 is lowered until it moves into abutment against the lower member 29, as illustrated by the right-hand portion of FIG. 9. Lower portions 83 of the passages 52 of the rings 51 then move into abutment against the enlargement 79. Those lower portions 83 are, for example, of forms which diverge towards the bottom. Fixing the bottom end-piece 7 to the guide tubes 11 by the screws 43 described above completes the assembly of the support skeleton 5. The upper plate 31 is then maintained in a state longitudinally abutting the lower member 29 and thereby longitudinally clamps the lower ends of the rods 3 against the member 29 by the enlargements 79. All the fuel rods 3 are then secured longitudinally and laterally relative to the bottom end-piece 7, thereby bringing about lateral securing of the rods 3 relative to the end-piece 7, which further reduces the risks of vibrations of the fuel rods 3 and damage owing to fretting. FIG. 10 illustrates a second variant of this embodiment. In this variant, the rings 75 have outer diameters that are reduced further, and are therefore smaller than the outer diameter of the claddings 17 of the fuel rods 3. The rings 75 are connected by shoulders 85 to the lateral surfaces of the lower plugs 19. The central passages 52 of the rings 51 have, in addition to the lower diverging portion 83, an upper portion 87 which diverges towards the top. The outer diameter of the projections 71 is reduced further than in the first variant of FIG. 9. In order to assemble the fuel rods 3 at the bottom end-piece 7, first the rings 75 are introduced in the passages 52 of the rings 51 of the grid 31, as indicated by the arrow 88 at the left-hand portion of FIG. 10. During that introduction operation, the tongues 77 become resiliently deformed laterally towards the inner side until the enlargements 79 are positioned below the frustoconical portions 83 and the shoulders 85 abut the upper surface of the anti-debris grid 31. The lower plugs 19 of the rods 3 are then assembled by being engaged with the upper grid 31. Subsequently, the upper grid 31 is moved into abutment against the lower unit 29 so that the projections 71 are introduced inside the rings 75. The projections 71 prevent deformation of the plates 77 and therefore the lower plugs 19 from being disengaged from the upper plate 31. Fixing the bottom end-piece 7 to the guide tubes 11 by the screws 43 completes the construction of the support skeleton 5. In that second variant, the lower ends of the fuel rods 3 are also secured longitudinally and laterally relative to the end-piece 7. In the third variant of FIG. 11, the lower plugs 19 of the fuel rods 3 comprise widened lower feet 89, for example, in the form of discs having a diameter greater than the outer diameter of the external claddings 17. After fitting the fuel rods 3, by the upper ends thereof, in the rings 51 of the grid 31, those feet 89 engage in lower countersinkings 91 that are provided in the rings 51. The feet 89, and therefore the lower ends of the fuel rods 3, are therefore secured longitudinally between the lower member 29 of the end-piece 7 and the upper plate 31, by the screws 43 for fixing to the guide tubes 11. In the variant of FIG. 12, the lower plugs 19 of the fuel rods 3 also comprise rings 75 which, however, are not split. Those rings 75 have been introduced in the passages 52 of the rings 51 and fixed to the rings 51 by expansion-rolling. The lower ends of the fuel rods 3 are therefore secured longitudinally and laterally to the upper plate 31 of the bottom end-piece 7 which is itself fixed, by the screws 43, to the member 29 of the bottom end-piece 7. FIG. 13 illustrates still another variant, in which the securing of the fuel rods 3 to the end-piece 7 is brought about by screws 43 similar to those used for fixing to the guide tubes 11. Thus, each nose 39 arranged below a rod 3 is formed by a head 45 of a screw 43, that has a shank 62 that extends through the corresponding unit 33 and that is screwed in the lower plug 19 of the corresponding rod 3. In each of the embodiments and in each of the variants described above, it is possible for the end-piece 7 not to comprise an anti-debris filter. It will again be appreciated that the presence, in the end-piece 7, of a maintaining arrangement, or an arrangement for laterally and/or longitudinally securing all the rods 3, may be envisaged separately from the use of noses 39 for orientating the flow of coolant water along the rods 3 because they independently allow the risks of vibration of the fuel rods 3 to be limited. In some variants, it is possible for some rods not to be maintained by the end-piece 7, but the majority of the rods remain in a maintained state. More generally, the principles described above may be used not only for assemblies which are intended for pressurized water reactors, but also for those intended for boiling water reactors (BWR).
054535620	claims	1. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste feed materials comprising, subjecting the feed materials contaminated with chemical compounds to a vacuum sufficient to expose the feed materials to a final pressure from about 400 mm Hg to about 50 mm Hg; simultaneously heating the feed materials to a temperature effective to volatilize the volatile and semi-volatile chemical contaminants, but below incineration temperature and below thermal desorption temperatures required at atmospheric pressure; substantially continuously removing the evolved vapors for a period of time sufficient to effect a desired degree of separation of the volatile and semi-volatile chemical contaminants from the feed materials. 2. A method as in claim 1, wherein the temperature employed to effect volatilization is equal to or below 600.degree. F. 3. A method as in claim 1, wherein the volatile and semi-volatile contaminants comprise halogenated organic chemicals. 4. A method as in claim 1, further comprising passing an inert gas other than steam through inert solids. 5. A method as in claim 4, wherein the inert gas is selected from the group consisting of nitrogen, carbon dioxide, helium and argon. 6. A method as in claim 1, wherein the concentration of any single organic contaminant in the treated feed materials after treatment is 25 ppm or less. 7. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste feed materials comprising, subjecting the feed materials contaminated with chemical compounds to a vacuum sufficient to expose the feed materials to a final pressure from about 400 mm Hg to about 50 mm Hg; simultaneously heating the feed materials to a temperature effective to volatilize the volatile and semi-volatile chemical contaminants, but below incineration temperature and below the thermal desorption temperature required at atmospheric pressure; substantially continuously removing the evolved vapors for a period of time sufficient to effect a desired degree of separation of the volatile and semi-volatile chemical contaminants from the feed materials, wherein the evolved vapors are treated prior to atmospheric discharge. 8. A method as in claim 7, wherein the temperature employed to effect volatilization is equal to or below 600.degree. F. 9. A method as in claim 7, wherein the contaminants comprise halogenated organic chemicals. 10. A method as in claim 7, further comprising passing an inert gas other than steam through inert solids. 11. A method as in claim 10, wherein the inert gas is selected from the group consisting of nitrogen, carbon dioxide, helium and argon. 12. A method as in claim 7, wherein the concentration of any single organic contaminant in the treated feed materials after treatment is 25 ppm or less. 13. A method for separating volatile and semi-volatile chemical contaminants from contaminated mixed waste solid materials comprising, in combination, the steps of: (a) removing from the ground solid materials contaminated with hazardous and radioactive pollutants; (b) introducing the contaminated solid materials into a batch mixing vessel; (c) drawing a vacuum on the mixing vessel while purging the mixing vessel with an inert purge gas; (d) agitating the contaminated solid materials in the mixing vessel in the presence of the inert gas while indirectly heating the solid materials to a temperature between about 200.degree. to about 600.degree. F.; (e) simultaneously with the heating and agitation of step (d) continuously drawing a vacuum until a final pressure from about 400 mm Hg to about 50 mm Hg on the mixing vessel is reached while maintaining a sweep stream of an inert gas; and (f) continuously removing by means of the vacuum, evolved vapors comprising substantially all of the volatile and semi-volatile chemical compounds originally contained in the contaminated solid materials.
042257905	abstract	A storage reel for flexible-cable remote manipulating means, which provides a form on which to store a flexible cable and its guide tube on the outside of the form, and which includes permanently fixed inside the form a relatively lighter weight storage tube, of Teflon or the like, for storing a supply of the flexible cable. The storage reel is disclosed in a system for isotope radiography.
051494914	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the present invention, a boiling-water reactor 100 comprises a vessel 102, a core 104, a chimney 106, a steam separator 108, and a dryer 110. Control rod drive housings 112 extend through the bottom of vessel 102 and support control rod guide tubes 113. Control rod guide tubes 113 extend to the bottom of core 104 so that control blades therein can be inserted into and retracted from core 104 to control its power output. Water flows, as indicated by arrows 114, into core 104 from below. This subcooled water is boiled within core 104 to yield a water/steam mixture which rises through core 104 and chimney 106, as indicated by an arrow 115. Steam separator 108 helps separate steam from water, and the released steam exits through a steam exit 116 near the top of vessel 102. Before exiting, any remaining water entrained in the steam is removed by dryer 110. Water is returned down a peripheral downcomer 118 by the force of the driving steam head provided by chimney 106. Feedwater enters vessel 102 through a feedwater inlet nozzle 120 and a feedwater sparger 122 to replenish and to help cool the recirculating water in downcomer 118. Core 104 is bounded from below by a core support plate 124, along with associated orificed support stubs 126, and bounded from above by a top guide 128. These structures support and aid in the installation of fuel bundles 130 that constitute core 104. Fuel bundles 130 are arranged in a two-dimensional array, as shown in FIG. 2. Spaces are left between groups of four fuel bundles for control rods 232 with cruciform cross sections to move vertically to regulate power output. Fuel bundles 130 are divided into three groups, a group of relatively fresh bundles 234, a group of bundles 236 at mid-life, and a group of bundles 238 near the end of their useful lifetime. Orificed support stubs 126 are likewise divided into three groups, small-orificed stubs 242 (small circles in FIG. 2), large-orificed stubs 244 (large circles in FIG. 2), and peripheral stubs 246 (at locations marked "P"), which also have small orifices. Fresh fuel bundles 234 are disposed over small-orificed stubs 242, mid-life bundles 236 are disposed over large-orificed stubs 244, and late-life fuel bundles 238 are disposed over peripheral stubs 246. The locations of fresh bundles 234 are radially between the more central locations of the mid-life bundles 236 and the more peripheral late-life bundles 238. Small-orificed stubs 242 and peripheral stubs 246 define 1" apertures through core support plate 124, while large-orificed stubs 244 define 2" apertures through core support plate 124. The fuel arrangement of FIG. 2 results from the fuel management method 300 illustrated in FIG. 3. Fresh fuel bundles are inserted (at step 301) into core locations defined by small-orificed stubs. A first reactor cycle, including operation and shutdown, is implemented (at step 302). During this first reactor cycle, the restricted coolant flow established by the small orifices result is a fast neutron spectrum, limiting fissioning and promoting the conversion of fertile U238 to fissile Pu241. The conversion/fission ratio is between about 0.7 to 0.8, compared to a 0.5 to 0.6 in a conventional fuel bundle arrangement. (A ratio in excess of 1.0 would characterize a breeder reactor which produces more fissile fuel than it uses.) This substantially increases the fertile fuel available at mid-life. During the present or a subsequent refueling cycle, the subject bundle, now at mid-life, is inserted (at step 303) into a more central location over a large-orificed stub. A second reactor operation cycle is implemented (at step 304). During this second cycle, the large-orificed stub permits a relatively fast coolant flow through the bundle, resulting in a smaller steam void, more moderation, and a more thermal neutron spectrum. As a result, fissioning is promoted at the expense of conversion. During this cycle, the conversion ratio is about 0.3-0.4. Thus, fewer actinide products are being generated, while those resulting from the first cycle are given at least the entire second cycle for burnup. While the present invention provides for disposal of a fuel bundle (at step 307) after this second cycle, as indicated by branch 310, a late-life bundle can be inserted into a peripheral location (at step 305). During a subsequent third cycle and shutdown (at step 306), the late-life bundle makes a modest contribution to core reactivity and shields core externals from the more intense radiation near the center of the core. Eventually, the spent fuel bundle is removed and disposed of (at step 307). In the illustrated embodiment, the different sized apertures through the core support plate were defined using stubs with different sizes of orifices. Alternatively, the apertures could be defined in the core support plate itself. Alternatively, an attachment could narrow the otherwise large orifice of a stub to provide smaller-orificed stubs. In this vein, the orifice constriction can be built into the bundles, and either adjusted or removed during a refueling operation. While the illustrated embodiment used only two orifice sizes, more gradations are employed in other embodiments. Further, coolant flow rates can be varied by location in ways not relying on flow apertures. While the illustrated embodiment shows core locations arranged in three bands in radial succession, many alternative arrangements are provided for. More bands can be used to provide a succession of steps toward locations with larger orifices and/or locations otherwise provided with faster coolant flow rates. Bands can alternate to smooth the reactivity profile along a core radius. For example, a small-orificed band can be inserted between two large-orificed bands to soften a thermal peak near the core center. Furthermore, orifice-define groups of locations need not be defined by bands at all. Checkerboard arrangements, random arrangements, and many alternatives are also provided for. Wherever a design analysis indicates excess reactivity, a small-orificed location can be exchanged for a large-orificed location. Fuel bundles can progress cycle by cycle. Alternatively, some fuel bundles can remain in place or be transferred within orifice size subgroup during a refueling cycle. The present invention provides for some bundles following patterns not in accordance with FIG. 3, as long as some fuel bundles progress from small-orificed locations to large-orificed locations. It should be noted that the present invention is compatible with many other fuel management strategies including bundle inversion to improve axial burnup uniformity. These and other modifications to and variations upon the described embodiments are provided for by the present invention, the scope of which is limited only by the following claims.
	description	This application is a continuation of, and claims the benefit of, U.S. patent application Ser. No. 09/302,075, filed on Apr. 28, 1999, now U.S. Pat. No. 6,765,217, which is incorporated by reference herein in its entirety. This disclosure pertains to, inter alia, charged-particle-beam (CPB) projection-optical systems for use in “mapping” CPB (e.g., electron beam or ion beam) microscopes, to methods for adjusting such projection-optical systems, and to use of such microscopes for observing and inspecting surfaces of objects. Charged-particle-beam (“CPB”, e.g., electron beam or ion beam) microscopes are in routine use for observing and inspecting intricate and highly integrated semiconductor circuits and the like as formed on suitable substrates. Such CPB microscopes include scanning electron microscopes (SEMs) and “mapping electron microscopes.” Whereas an SEM performs illumination and imaging from one point to another point on a specimen, a mapping electron microscope performs illumination and imaging from one surface to another surface of the specimen. Much research and development has been directed in recent years to improving the CPB mapping projection-optical systems used in mapping electron microscopes. The structure of a conventional mapping electron microscope is summarized below, with reference to FIG. 1. A primary electron beam (also termed an “irradiation electron beam”) PB is emitted by an electron gun 21. The primary electron beam PB passes through an irradiation lens system 22 and enters a Wien filter 25. The Wien filter 25 typically comprises a magnetic pole 26 and an electrical pole 27. The Wien filter 25 bends the trajectory of the primary electron beam PB. After passing through the Wien filter 25, the primary electron beam PB passes through an aligner 30 and through an objective lens system 24 so as to be incident on the surface of a specimen 23. The irradiation lens system 22, Wien filter 25, aligner 30, and objective lens system 24 collectively are termed the “irradiation-optical system” or “primary optical system.” Impingement of the primary electron beam PB on the surface of the specimen 23 generates relatively high-energy electrons that are reflected from the surface of the specimen 23 and relatively low-energy secondary electrons that are emitted from the surface of the specimen 23. The secondary electrons are normally used for imaging. The secondary electrons (formed into an “observation electron beam” or “secondary electron beam” OB) return through the objective lens system 24 and the aligner 30 and re-enters the Wien filter 25. Rather than experiencing trajectory bending by the Wien filter 25, the observation electron beam OB passes straight through the Wien filter 25. The observation electron beam OB then passes through an imaging lens system 28 and enters a detector 29. Observations of the specimen 23 are based on information in the observation electron beam OB as detected by the detector 29. The objective lens system 24, aligner 30, Wien filter 25, and imaging lens system 28 collectively comprise a “mapping optical system” or “secondary optical system.” The Wien filter 25 is an electromagnetic prism also termed an “E×B” (“E cross B”). By imposing Wien's condition on the primary electron beam PB, the Wien filter 25 imparts a desired deflection to the trajectory of the primary electron beam PB, while not deflecting the trajectory of the secondary electron beam OB. Upon passing through the Wien filter 25, the primary electron beam PB can have, e.g., a linear, rectangular, circular, or elliptical transverse (sectional) profile. It is necessary to be able to adjust accurately various components of the CPB mapping projection-optical system (e.g., align the illumination field of the primary optical system with the observation field of the secondary optical system) before use in order to observe and inspect the surface of the specimen 23 accurately. To such end, it would be advantageous to be able to adjust (e.g., alignment with optical axis, aberration correction) independently the primary optical system, the secondary optical system, and the Wien filter 25 (e.g., by adjusting respective voltages (or currents) applied to components in the primary optical system, the secondary optical system, and the cathode lens, and by adjusting the electromagnetic field generated by the Wien filter 25). Conventional adjustment methods require excessive time and effort to perform. It also would be advantageous to be able to determine positional coordinates of the specimen being observed or inspected using a CPB mapping microscope. According to one conventional scheme for making such a determination, an off-axis light-optical system (i.e., an optical system for light) is used in conjunction with the CPB-optical system. In such a scheme, the specimen is mounted on a stage provided with fiducial marks (e.g., a pattern of lines and spaces). Unfortunately, however, conventional practice has revealed much difficulty in detecting such marks using both a light-optical system and a CPB-optical system. Difficulty is also conventionally encountered in detecting fiducial marks configured as a grooved pattern (e.g., scribe lines), which readily can be detected using an optical microscope but not by a CPB-optical system. In other words, marks that can be detected readily using light are usually not detectable using a charged particle beam. This makes it difficult to select a fiducial mark that is optimal for use with both a CPB-optical system and an off-axis light-optical system. According to another conventional method for evaluating optical performance (e.g., resolution and aberration) of a CPB mapping microscope, an “evaluation chart” is placed at the position of the specimen 23 in FIG. 1. The evaluation chart is typically a pattern comprising ultra-fine features defined by deposition or microlithography. The evaluation chart is irradiated using the primary electron beam PB, and an image is produced from the observation beam OB generated therefrom. Unfortunately, whenever optical performance is evaluated using an evaluation chart in such a manner, the optical axis of the irradiation-optical system and the optical axis of the mapping optical system must be adjusted simultaneously by making simultaneous adjustments to the Wien filter and the aligner. This requires that the evaluation chart be illuminated uniformly with the primary electron beam PB in order to check the optical performance of the mapping electron microscope. The Wien filter's condition is found while continuously changing the electromagnetic-pole induction parameters in the Wien filter 25 so that the trajectory of the secondary electron beam is not deflected. Changing the electromagnetic-pole induction parameters in such a manner causes a simultaneous change in the uniformity of illumination by the primary electron beam. Consequently, it is necessary to readjust the optical axis of the illumination optical system continually. In addition, whenever the secondary electron beam is deflected by the aligner and axially aligned with the objective lens system, the primary electron beam is simultaneously deflected, thereby changing the uniform illumination and making it necessary again to readjust the optical axis of the illumination optical system. Thus, such conventional evaluations of optical performance are extremely complex to perform. The kinetic-energy distribution of electrons in the secondary electron beam emitted from the specimen is very sensitively affected by the type and shape of the specimen and the irradiation angle of the secondary electron beam. This instability of the kinetic-energy distribution of the secondary electron beam adds even more complexity to conventional evaluations of the optical performance of the mapping electron microscope, and makes it impossible to determine, e.g., the magnitude of chromatic aberration. The shortcomings of the prior art noted above are addressed by the various combinations of features described herein that provide, inter alia, apparatus for charged-particle-beam (CPB) projection-optical systems, and methods for adjusting such systems, allowing rapid and accurate adjustments, even by a relatively unskilled operator. The instant disclosure provides, according to one aspect, charged-particle-beam mapping projection-optical systems. Representative embodiments of such systems comprise an irradiation-optical system, an E×B beam separator (i.e., Wien filter or “E×B”), an objective-optical system, an imaging-optical system, and an adjustment-beam source. The irradiation-optical system directs an irradiation charged particle beam along a first axis from an irradiation-beam source. The E×B beam separator is configured and situated to receive the irradiation beam from the irradiation-optical system and to direct the irradiation beam downstream of the E×B beam separator. The objective-optical system is configured and situated to receive the irradiation beam from the E×B beam separator, direct the irradiation beam to be incident on a surface of a specimen located at a position downstream of the objective-optical system, receive an observation charged particle beam generated by impingement of the irradiation beam on the specimen surface, and direct the observation beam to the E×B beam separator. The E×B beam separator causes the observation beam to propagate along a second axis having a direction different than the first axis. The imaging-optical system is configured and situated to receive the observation beam from the E×B beam separator and to direct the observation beam from the E×B beam separator to a detector. The adjustment-beam source is configured to emit an adjustment charged particle beam, and can be situated at the specimen position so as to direct the adjustment beam, in place of the observation beam, through the objective and imaging-optical systems to the detector. The adjustment beam produced by the adjustment-beam source has an emission profile at the specimen position. The emission profile desirably corresponds to at least one of a dot, a line, a plane, a cross, or an L-shaped profile. The adjustment beam can be any of various charged particle beams, such as an electron beam. The adjustment-beam source desirably produces the adjustment beam having a kinetic energy equal to a kinetic energy of the observation beam as generated at the specimen surface. An exemplary adjustment-beam source is a cold cathode. To provide an acceleration of the adjustment beam as it propagates to the detector, an electrode can be situated object-wise of the objective-optical system so as to generate a potential relative to the adjustment-beam source sufficient to accelerate the adjustment beam as the adjustment beam propagates to the detector. According to another aspect of the disclosure, methods are provided for operating a charged-particle-beam mapping projection microscope. In representative embodiments of such methods, an irradiation charged particle beam is directed along a first axis from an irradiation-beam source through an irradiation-optical system to an E×B beam separator, then passed through the E×B beam separator and through an objective-optical system so as to cause the irradiation beam to impinge on a surface of a specimen at an object-surface plane. Such impingement generates, from the impingement, an observation charged particle beam propagating from the specimen toward the objective-optical system. The observation beam is passed through the objective-optical system and the E×B beam separator along a second axis having a different direction than the first axis, and then through an imaging-optical system to a detector. The subject methods comprise a process for adjusting the objective-optical system and imaging-optical system. In such an adjustment process, the specimen (situated at the object-surface plane) is replaced with an adjustment-beam source that emits an adjustment charged particle beam. While passing the adjustment beam through the objective-optical system, the E×B beam separator, and the imaging-optical system, electrical power is applied only to the objective-optical system. Meanwhile, one or more of an axial alignment and an aberration characteristic of the objective-optical system is determined. If desired or required, the one or more of an axial alignment and an aberration characteristic of the objective-optical system can be adjusted based on the determination. Electrical power can be applied to the imaging-optical system as well as the objective-optical system, during which one or more of an axial alignment and an aberration characteristic of the imaging-optical system is determined. If desired or required, the one or more of an axial alignment and an aberration characteristic of the imaging-optical system can be adjusted based on the determination. According to another aspect of the disclosure, CPB mapping projection-optical systems are provided. Representative embodiments of such systems comprise an irradiation-optical system, an E×B beam separator, an objective-optical system, an imaging-optical system, an alignment-beam source, and an alignment-optical system. The irradiation-optical system directs an irradiation charged particle beam along a first axis from an irradiation-beam source. The E×B beam separator is configured and situated so as to receive the irradiation beam from the irradiation-optical system and to direct the irradiation beam downstream of the E×B beam separator. The objective-optical system is configured and situated to receive the irradiation beam from the E×B beam separator, direct the irradiation beam to be incident on a specimen surface located at an object-surface plane downstream of the objective-optical system, receive an observation charged particle beam generated by impingement of the irradiation beam on the specimen surface, and direct the observation beam to the E×B beam separator, wherein the E×B beam separator causes the observation beam to propagate along a second axis having a direction different than the first axis. The imaging-optical system is configured and situated to receive the observation beam from the E×B beam separator and to direct the observation beam from the E×B beam separator to a first detector. The alignment-beam source is configured to emit an alignment beam with respect to the object-surface plane so as to cause the alignment beam to acquire data regarding an alignment characteristic of the object surface. The alignment-optical system is situated off-axis from the objective and imaging-optical systems and is configured to direct the alignment beam from the object surface to a second detector that detects the data. The alignment-beam source can be situated at and movable within the object-surface plane. For example, the alignment-beam source can be defined on a fiducial plate, and the fiducial plate can comprise a fiducial mark. In another embodiment, the alignment-beam source is situated remotely from the object surface and is directed by a lens to the object surface. In the latter instance, a fiducial mark can be situated on the object surface. The fiducial mark desirably is configured to be optimal for the irradiation-optical system, the objective-optical system, the imaging-optical system, and the off-axis optical system. By way of example, the alignment beam can be a beam of light or a charged particle beam. In the latter instance, the alignment beam can be an electron beam, wherein the off-axis optical system is a scanning electron microscope, and the alignment-beam source desirably has an emission profile (at the object-surface plane) that is at least one of a dot, a line, a cross, or an L-shaped profile. As a charged particle beam, the alignment beam desirably has a kinetic energy equal to the kinetic energy of the observation beam. To produce a CPB alignment beam, the alignment-beam source can be a cold cathode. In addition, an electrical potential can be imposed between the alignment-beam source and an object-wise surface of the objective-optical system. In such an instance, the potential causes an acceleration of the alignment beam as the alignment beam propagates through the objective-optical system. According to another aspect of the disclosure, methods are provided for operating a charged-particle-beam mapping projection microscope. In such methods, an irradiation charged particle beam is directed along a first axis from an irradiation-beam source through an irradiation-optical system to an E×B beam separator, then passed through the E×B beam separator and through an objective-optical system so as to cause the irradiation beam to impinge on a surface of a specimen at an object-surface plane. Such impingement generates an observation charged particle beam propagating from the specimen toward the objective-optical system. The observation beam is passed through the objective-optical system and the E×B beam separator along a second axis having a different direction than the first axis, and then through an imaging-optical system to a detector. In such methods, a process is provided for adjusting the objective-optical system and the imaging-optical system. A representative embodiment of such a process comprises placing an adjustment-beam source at the object-surface plane (the adjustment-beam source being operable to emit an adjustment charged particle beam). An electrical potential and electrical current applied to the E×B beam separator are adjusted so as to align an image formed on the detector by the adjustment-beam source when an electrical potential and electrical current are not applied to the E×B beam separator with an image formed on the detector by the adjustment-beam source when an electrical potential and electrical current are applied to the E×B beam separator. The imaging-optical system can comprise a stigmator that corrects aberration in the image formed on the detector. Also, electrical energy applied to at least one of the objective-optical system and the imaging-optical system can be adjusted while adjusting the electrical energy applied to the detector. By way of example, the adjustment beam can be an electron beam. In such an instance, the adjustment beam desirably has a kinetic energy equal to the kinetic energy of the observation beam. The process can further comprise providing a potential difference between the adjustment-beam source and a specimen-wise surface of the objective-optical system, wherein the potential difference serves to accelerate the adjustment beam. According to another aspect, CPB mapping projection-optical systems are provided, that comprise an irradiation-optical system, an E×B beam separator, an objective-optical system, an imaging-optical system, and an adjustment-beam source. The irradiation-optical system directs an irradiation charged particle beam along a first axis from an irradiation-beam source. The E×B beam separator is configured and situated to receive the irradiation beam from the irradiation-optical system and to direct the irradiation beam downstream of the E×B beam separator. The objective-optical system is configured and situated to receive the irradiation beam from the E×B beam separator, direct the irradiation beam to be incident on a specimen surface located at an object-surface plane downstream of the objective-optical system, receive an observation charged particle beam generated by impingement of the irradiation beam on the specimen surface, and direct the observation beam to the E×B beam separator, wherein the E×B beam separator causes the observation beam to propagate along a second axis having a direction different than the first axis; the imaging-optical system is configured and situated to receive the observation beam from the E×B beam separator and to direct the observation beam from the E×B beam separator to a first detector. The adjustment-beam source is configured to emit an adjustment beam with respect to the object-surface plane so as to cause the adjustment beam to acquire data regarding a position of the object surface. Desirably, the E×B beam separator is connected to a variable-power supply to permit an electrical potential and electrical current applied to the E×B beam separator to be adjusted as required such that an image formed on the detector by the adjustment beam when the electrical potential and electrical current are not applied to the E×B beam separator is aligned with an image formed on the detector by the adjustment beam when the electrical potential and electrical current are applied to the E×B beam separator. The imaging-optical system can include stigmators that correct aberration in the image formed on the detector. In the method, the voltage (or current) applied to at least one of the objective-optical system and the imaging-optical system is adjusted while adjusting the voltage applied to the detector. According to another aspect, CPB mapping projection-optical systems are provided. Representative embodiments of such a system comprise an irradiation-optical system, an E×B beam separator, an objective-optical system, an imaging-optical system, an adjustment-beam source, and an “evaluation chart.” The irradiation-optical system directs an irradiation charged particle beam along a first axis from an irradiation-beam source. The E×B beam separator is configured and situated to receive the irradiation beam from the irradiation-optical system and to direct the irradiation beam downstream of the E×B beam separator. The objective-optical system is configured and situated to receive the irradiation beam from the E×B beam separator, direct the irradiation beam to be incident on a specimen surface located at an object-surface plane downstream of the objective-optical system, receive an observation charged particle beam generated by impingement of the irradiation beam on the specimen surface, and direct the observation beam to the E×B beam separator. The E×B beam separator causes the observation beam to propagate along a second axis having a direction different than the first axis. The imaging-optical system is configured and situated to receive the observation beam from the E×B beam separator and to direct the observation beam from the E×B beam separator to a first detector. The adjustment-beam source is configured to emit an adjustment beam with respect to the object surface so as to cause the adjustment beam to acquire data regarding a position of the object surface. The evaluation chart is configured for insertion at the object-surface plane. The evaluation chart spontaneously emits an evaluation electron beam for evaluating an optical-performance characteristic of the imaging-optical system. The evaluation electron beam desirably has a kinetic energy that is equal to the kinetic energy of the observation beam. Also, the evaluation electron beam can have an emission profile, such as a dot-shaped profile, a line-shaped profile, or a planar profile. The evaluation chart can comprise a hot-electron emitter and can be disposed so that it can be inserted and removed at the position of the specimen surface. Such an evaluation chart spontaneously emits an evaluation electron beam for inspecting the optical performance of the mapping optical system. The kinetic energy of the evaluation beam desirably is equal to the kinetic energy of the observation beam. It is also preferable for the emission profile of the evaluation beam to have any one of a dot shape, a line shape, or a plane shape. The foregoing and additional features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. Various aspects of the invention are exemplified in multiple representative embodiments, as described below, that are not intended to be limiting in any way. A charged-particle-beam (CPB) mapping projection-optical system according to this embodiment is depicted in FIG. 2. Main subassemblies include a primary column 32, a secondary column 33, and a chamber 34. As can be discerned from the figure, each of the columns 32, 33 and the chamber 34 are in communication with each other and enclose a common space. The space is evacuated as required by a vacuum system (not shown) typically including a turbo-molecular pump. The chamber 4 encloses an X-stage 35 movable in the X-direction by an X-stage driver 36 and a Y-stage 37 movable in the Y-direction by a Y-stage driver (not shown but understood to be configured similarly to the X-stage driver 36). Also inside the chamber 34 are a cold cathode 38 (serving in this embodiment as a source of an “adjustment beam” discussed below), a specimen 39, an X-movable mirror 40 and a Y-movable mirror (not shown but understood to be similar to the X-movable mirror 40) mounted on the X-stage 35. The cold cathode 38 can be a so-called “self-emitting beam source” that emits an electron beam (or other suitable charged particle beam) having a low kinetic energy (e.g., around 0.5 to 2 eV for electrons in this embodiment). Such a kinetic-energy level is near the value of the kinetic energy of a secondary electron beam K emitted from the object surface of the specimen 39, as described further below. The cold cathode 38 can be, e.g., a MOS-tunnel cold cathode, a Poly-Si/i-Si/n-Si cathode, a silicon field emitter, or analogous device. The cold cathode 38 can be fabricated by microlithography to form the requisite self-emitting pattern such as dots, lines-and-spaces, crosses, L-shapes, etc. Turning now to the primary column 32, a primary beam S (also termed an “irradiation beam”) is produced by an electron gun 41 (or other suitable CPB source). The primary beam S passes through a “primary optical system” (also termed an “irradiation-optical system”) and enters a Wien filter (also termed an “E×B” or “E×B beam separator”) 42. The primary optical system in this embodiment comprises a field-stop FS1, irradiation lenses 43, 44, 45, aligners 46, 47, a scanning aligner 48, and an aperture 49. The irradiation lenses 43, 44 45 can be, e.g., electron lenses, circular lenses, quadrupole lenses, or octapole lenses. The trajectory of the primary beam S is deflected by the Wien filter 42 which directs the primary beam to an aperture stop AS at which a crossover image of the electron gun 41 is formed. Passing through the aperture stop AS, the primary beam S then passes through a first aligner 50. The primary beam is then refracted by passage through a cathode lens 51 as to illuminate the specimen 39 with Koehler illumination. The aperture stop AS, first aligner 50, and cathode lens 51 collectively comprise an “objective-optical system.” As the specimen 39 is illuminated by the primary beam S, a secondary beam K and reflected electrons are produced. The distribution of charged particles in the secondary beam and in the reflected electrons corresponds with the surface shape, material distribution, and potential changes, etc., of the specimen 39. The secondary beam K primarily is used as an “observation beam” or “image-forming beam.” As discussed above, the kinetic energy of the secondary beam K is “low” at around 0.5 to 2 eV in this embodiment. The secondary beam K emitted from the specimen 39 sequentially returns through the cathode lens 51, the first aligner 50, the aperture stop AS, the Wien filter 42, and a “secondary optical system” (or “imaging-optical system”) as the secondary beam K propagates to a detector 52. The secondary optical system in this embodiment comprises a front imaging lens group 53, a rear imaging lens group 54, stigmators 55, 56, a second aligner 57, a third aligner 58, and a field-stop FS2. The field-stop FS2 is in a conjugate relationship with the object-surface plane about the cathode lens 51 and the front imaging lens group 53. The front imaging lens group 53 and the rear imaging lens group 54 of the secondary optical system can be electron lenses such as, e.g., circular lenses, quadrupole lenses, or octapole lenses. The secondary beam K incident on the detection surface of the detector 52 is formed by the secondary optical system into an enlarged image of the specimen 39. The detector 52 can comprise an MCP (micro-channel plate) for amplifying incident electrons, a fluorescence plate for converting the electrons to light, and a vacuum window for emitting the converted light to the outside of the secondary column 33. Light emitted from the detector 52 (i.e., an optical image of the specimen 39) is transmitted by a relay lens 60 to a pickup element 61 (e.g., a CCD or the like). The light incident to the pickup element 61 is converted thereby to a photoelectric signal that is transmitted to a controller 62. The controller 62 converts the photoelectric signal into an electrical signal that is routed to a CPU 63. The CPU 63 produces a corresponding video signal that is routed to a display 64 that displays an image of the specimen 39. The CPU 63 also produces a control signal that is routed to a first power controller 65, a second power controller 66, and an electromagnetic-field controller (not shown in FIG. 2). The first power controller 65 controls electrical power applied to components in the primary optical system, the second power controller 66 controls electrical power applied to the cathode lens 51, the first aligner 50, and the secondary optical system. The electromagnetic-field controller controls the electromagnetic field generated by the Wien filter 42. The CPU 63 also produces a control signal that is routed to the X-stage driver 36 and the Y-stage driver, and receives positional information about the stages 35, 37 from an X-interferometer 67 and a Y-interferometer (not shown, but understood to be configured similarly to the X-interferometer). Thus, multiple specimens can be observed and inspected sequentially. The Wien filter (E×B) 42 is now described in connection with FIGS. 3(A)–3(C). As shown in FIG. 3(A), the primary beam S emitted from the electron gun 41 is acted upon by the lens action of the primary optical system and thereby focused. Upon entering the Wien filter 42, the primary beam S experiences a deflection of its trajectory. The trajectory is bent because, as electrons in the primary beam S having a charge “q” proceed at velocity “v” in the +Z direction into the electrical field E and the magnetic field B (orthogonal to each other) produced by the Wien filter 42, the electrons are subjected to the resultant of the force FE (=qE) of the electrical field and the force FB (=−qvB) of the magnetic field, which are exerted in the −X-direction. Thus, the trajectory of the primary beam S is bent within the X-Z plane. Meanwhile, the secondary beam K (produced as the specimen 39 is irradiated by the primary beam S) is acted upon by the lens action of the cathode lens 51. The secondary beam passes through the aperture stop AS situated at the focal position of the cathode lens 51 and enters the Wien filter 42. The secondary beam passes through the Wien filter 42 without experiencing any change in trajectory. The reason is shown in FIG. 3(C). As electrons in the secondary beam having a charge “q” proceed at a velocity “v” in the −Z direction into the orthogonal electrical and magnetic fields E, B, respectively, the electrons are subjected to the resultant of the force FE of the electrical field (which is exerted in the −X-direction) and the force FB of the magnetic field (which is exerted in the +X-direction). The respective absolute values of the force FE and the force FB desirably are set so that they are equal (i.e., E=vB) so that “Wien's condition” is fulfilled. Hence, the force FE and the force FB cancel each other out and consequently reduce to zero any force that would otherwise affect the secondary beam K. As a result, the secondary beam K proceeds straight through the Wien filter 42. As described above, the Wien filter 42 has the function of a so-called electromagnetic prism, which selects the trajectory of a charged particle beam passing through it. Adjustment of the CPB mapping projection-optical system according to this embodiment is described in connection with FIG. 4. For adjustment purposes, the cold cathode 38 is used to form a “dot” pattern. As an overall “coarse” adjustment procedure, first the optical axis of the secondary optical system is aligned, then the electromagnetic field of the Wien filter 42 is adjusted, and then the optical axis of the primary optical system is adjusted using the dot-pattern produced by the cold cathode 38. As shown in FIG. 4, the cold cathode 38 is situated below the cathode lens 51. Next, the cathode lens 51 is energized by applying electrical energy thereto, while all other lenses are OFF. The cold cathode 38 produces an “adjustment beam” T that enters the cathode lens 51. In the cathode lens 51, the adjustment beam T is subjected to the electrical field produced by the cathode lens 51. After passing through the cathode lens 51, the adjustment beam T, similar to the secondary beam K described above, passes in sequence through the first aligner 50, the aperture stop AS, the Wien filter 42, and the secondary optical system. The adjustment beam then enters the detector 52. Dot-pattern data carried by the adjustment beam T incident to the detector 52 (similar to the secondary beam K) are transferred sequentially to the relay lens 60, the pickup element 61, the controller 62, and the CPU 63. The resulting image of the dot-pattern is displayed on the display 64. Since no electrical power is being impressed at this time on lenses other than the cathode lens 51, the force to which the adjustment beam T is subjected by the time it reaches the detector 52 is only the electrical field produced by the cathode lens 51. In such a condition, the image of the dot-pattern formed on the surface of the detector 52 is defocused by causing the voltage delivered to the cathode lens 51 to fluctuate in an AC fashion (thereby causing the cathode lens 51 to “wobble”). If the dot-pattern is not aligned with the optical axis of the cathode lens 51, the image of the dot-pattern on the display 64 will move (in response to the defocusing) within a plane that is perpendicular to the optical axis. The X-stage 35 and Y stage 37 are then shifted as required to cause the image of the dot-pattern on the display 64 to remain stationary regardless of the defocusing. When the image of the dot-pattern remains stationary on the display 64, the dot-pattern is actually aligned with the optical axis of the cathode lens 51. This completes adjustment of the optical axis of the cathode lens 51. Next, in addition to the cathode lens 51, electrical power is also applied to the front imaging lens group 53. The parameters of applied electrical energy are established such that an image of the dot-pattern produced by the cold cathode 38 is formed on the detector 52. As with the adjustment of the cathode lens 51, the electrical power applied to the first aligner 50 is adjusted while the voltage applied to the front imaging lens group 53 is fluctuated in an AC fashion. Such adjustment continues until the image of the dot-pattern as viewed on the display 64 no longer moves in response to the defocusing, at which time the optical axis of the front imaging lens group 53 is aligned with the optical axis of the cathode lens 51 adjusted previously. Next, in addition to the cathode lens 51 and the front imaging lens group 53, electrical power is also applied to the rear imaging lens group 54. The power parameters are established such that an image of the dot-pattern of the cold cathode 38 is formed on the detector 52. The electrical power applied to the second aligner 57 is adjusted while the voltage applied to the rear imaging lens group 54 is fluctuated in an AC fashion. Such adjustment continues until the image of the dot-pattern as viewed on the display 64 no longer moves, at which time the optical axis of the rear imaging lens group 54 is aligned with the optical axis of the cathode lens 51 and of the front imaging lens group 53 adjusted previously. Finally, the electrical power applied to the third aligner 58 is adjusted to move the image of the dot-pattern to the center of the detector 52, thereby aligning the center of the detector 52 with the optical axis. Thus, the optical axes of the cathode lens 51 and the secondary optical system are aligned with each other. Adjustment of the adjustment beam T can be accelerated by providing a potential difference between the cold cathode 38 and an electrode positioned object-wise of the cathode lens 51 by means of an acceleration power supply 68. After adjusting the respective optical axes of the cathode lens 51 and the secondary optical system, as described above, the desired next step is to adjust the primary optical system and the Wien filter 42. At this time, Wien's condition for the Wien filter 42 and the secondary optical system is found so that the image of the dot-pattern on the display 64 does not move even when power to the Wien filter 42 is turned ON and OFF. Thus, in this embodiment, the illumination field of the primary optical system and the observation field of the secondary optical system are aligned quickly and accurately, yielding an excellent video image as produced by the CPB-optical system. The optical axis of the secondary optical system was adjusted in this embodiment by forming a dot-pattern on the cold cathode 38. Alternatively, aberrations similarly can be analyzed and corrected using a dot-pattern by detecting the video image while defocusing the dot-image or by using the intensity distribution of the dot-image at the detector 52. Spherical aberration in the secondary optical system can be corrected if a line-and-space pattern is used instead of a dot-pattern for the pattern formed on the cold cathode 38. Distortion in the secondary optical system can be evaluated and corrected if a cross mark or an L-shaped mark is used. Whereas a cold cathode 38 was used to produce the adjustment beam in this embodiment, an electron gun alternatively can be used for adjustment purposes. In any event, the emission profile of the adjustment-beam source at the object-surface plane thereof desirably is at least one of a dot, a line, a cross, or an L-shape. Whereas the trajectory of the primary beam S was bent by the Wien filter 42, and the secondary beam (as a representative charged particle beam) K proceeded in a straight path, the system alternatively can be configured so that the primary beam S proceeds straight and the trajectory of the secondary beam K is bent. Whereas a CPB mapping projection-optical system was described above in which an electron beam was used, it will be understood that a CPB mapping projection-optical system alternatively can employ, e.g., an ion beam rather than an electron beam. The CPB mapping projection-optical system according to this embodiment is a so-called “surface-to-surface” CPB mapping projection-optical system that illuminates an object surface using an electron beam from a beam source and forms an image thereof at an image-surface plane. Such a system can be applied not only as a simple apparatus for observation or inspection of a specimen, but also as an exposure apparatus for making semiconductor devices, or the like. With this embodiment, as described above, since adjustment of the objective-optical system and the imaging-optical system each can be performed independently, using a self-emitting adjustment-beam source at the object-surface plane, a CPB mapping projection-optical system and adjustment method are provided with which quick and accurate adjustments can be performed. With respect to this embodiment, reference is first made to FIG. 5 in which components that are similar to corresponding components in the first representative embodiment have the same reference designators. As in the first embodiment, the FIG. 5 embodiment comprises a primary column 32, a secondary column 33, and a chamber 34 all evacuated by a suitable vacuum system (not shown). Inside the chamber 34 are an X-stage 35 (movable in the X-direction by an X-stage driver 36) and a Y stage 37 (movable in the Y-direction by a Y-stage driver, not shown). On the X-stage 35 are mounted a “fiducial plate” 70, a specimen 39, an X-movable mirror 40, and a Y-movable mirror (not shown). A primary beam S is produced by an electron gun 41 situated inside the primary column 32. The primary beam S passes through the “primary optical system” and enters the Wien filter (E×B) 42. The primary optical system comprises a field-stop FS1, irradiation lenses 43–45, aligners 46–47, a scanning aligner 48, and an aperture 49. The irradiation lenses 43–45 are, e.g., electron lenses as described in the first representative embodiment. The trajectory of the primary beam S is deflected by the Wien filter 42 toward the aperture stop AS at which a crossover image of the electron gun 41 is formed. After passing through the aperture stop AS, the primary beam S passes through a first aligner 50 and is then subjected to the lens action of a cathode lens 51. The primary beam then illuminates the specimen 39 with Koehler illumination. As a result of the primary beam S irradiating the specimen 39, a secondary beam K and reflected electrons are produced. The secondary beam and the reflected electrons have respective distributions that correspond with the surface shape, material distribution, and potential changes exhibited by the specimen 39. Of these, the secondary beam K primarily is used as an observation beam. As discussed above, the kinetic energy of the secondary beam K in this embodiment is “low” at around 0.5 to 2 eV. The secondary beam K emitted from the specimen 39 sequentially passes through the cathode lens 51, the first aligner 50, the aperture stop AS, the Wien filter 42, and a “secondary optical system.” The secondary beam K then enters a detector 52. The secondary optical system comprises a front imaging lens group 53, a rear imaging lens group 54, stigmators 55–56, a second aligner 57, a third aligner 58, and a field-stop FS2. The field-stop FS2 is in a conjugate relationship with the object-surface plane about the cathode lens 51 and the front imaging lens group 53. The front imaging lens group 53 and rear imaging lens group 54 typically are electron lenses, as discussed in the first representative embodiment. The secondary electron beam K incident on the detection surface of the detector 52 is formed by the secondary optical system into an enlarged image of the specimen 39. The detector 52 in this embodiment desirably comprises an MCP (Micro-Channel Plate) for amplifying the incident electrons, a fluorescent plate for converting the electrons to light, and a vacuum window for emitting the converted light to the outside of the secondary column 33 (since the interior of the secondary column 33 is normally under a vacuum). The light emitted from the detector 52, i.e., the optical image of the specimen 39, is transmitted by a relay lens 60 to a pickup element 61 such as a CCD or the like. The light incident to the pickup element 61 is converted to a photoelectric signal that is routed to a controller 62. The photoelectric signal routed to the controller 62 is converted into a corresponding electrical signal that is routed to a CPU 63 that produces a corresponding video signal delivered to a display 64 that displays the image of the specimen 39. The CPU 63 also produces a control signal delivered to a first power controller 65, a second power controller 66, and an electromagnetic-field controller (not shown in the figure). The first power controller 65 controls the electrical energy applied to components of the primary optical system; the second power controller 66 controls electrical energy applied to the cathode lens 51, the first aligner 50, and the secondary optical system; and the electromagnetic-field controller controls the electromagnetic field generated by the Wien filter 42. The CPU 63 also generates respective control signals routed to the X-stage driver 36 and the Y-stage driver, and receives positional information about the X- and Y-stages from an X-interferometer 67 and a Y-interferometer (not shown), thereby allowing multiple specimens sequentially to be observed and inspected. An off-axis optical system is configured as an optical microscope in this embodiment. An alignment-light flux A exits an optical fiber 71 or analogous appliance that delivers the alignment-light flux A from a remote light source (not shown) such as a laser diode or the like. The alignment-light flux A is converged by a lens 72 and enters a half-mirror 73. The alignment-light flux A reflected by the half-mirror 73 enters a vacuum window 74. The vacuum window 74 desirably is a parallel plate to allow ready transmission of incoming and exiting light of the alignment-light flux A into and out of, respectively, the secondary column 33 which is maintained under vacuum. Passing through the vacuum window 74, the alignment-light flux A is reflected by a mirror 75 and is refracted by an objective lens 76 (including an aperture stop, not shown, at which an image is formed). After passing through the objective lens 76, the alignment-light flux A illuminates the object surface on the X-stage 35 with Koehler illumination. The alignment-light flux A reflected by the object surface returns through the objective lens 76, is reflected by the mirror 75, passes through the vacuum window 74, and is incident to the half-mirror 73. The returning alignment-light flux A is transmitted by the half-mirror 73, passes through an index plate 77 and lens 78, and enters a CCD 79 on which an image of the object surface is formed. A photoelectric signal generated by the image on the CCD 79 is routed to a second controller 80 that converts the photoelectric signal into a corresponding electrical signal that is routed to the CPU 63. Whereas video processing in this embodiment desirably encompasses processing and routing of signals from the CCD 79 in the off-axis optical system to the CPU 63, such processing alternatively can be performed by LSA (Laser Step Alignment) or LIA (Laser Interferometric Alignment), for example, commonly used in optical projection-exposure devices. Whereas a half-mirror 73 desirably is used as a light splitter in this embodiment, a deflection beam splitter alternatively could be used instead, by way of example. The Wien filter 42 is constructed and operates as described above in Representative Embodiment 1. An exemplary fiducial plate 70 is shown in FIG. 6, and defines a dot-pattern 70a and line-and-space patterns 70b, 70c. The dot-pattern 70a is a self-emitting pattern formed on a cold cathode by electron-beam microlithography. The dot-pattern 70a can be, e.g., a circular pattern with a diameter of about 80 nm. The dot-pattern 70a also serves as a source of the alignment beam T; i.e., the dot-pattern 70a can serve as a fiducial mark for the CPB-optical system. A “cold cathode” is a self-emitting beam source that emits an electron beam having a low kinetic energy. The magnitude of the kinetic energy is at or near the magnitude of the kinetic energy of the secondary beam K emitted from the object surface of the specimen 39 described above. The cold cathode can be, e.g., a MOS-tunnel cold cathode, a poly-Si/i-Si/n-Si cathode, a silicon field emitter, or the like. The line-and-space patterns 70b, 70c include, e.g., linear vertical and horizontal, respectively, features arrayed at equal intervals (e.g., 4 μm wide). The features desirably are defined in metal on a silicon substrate of the fiducial plate 70, and have a configuration similar to corresponding alignment marks on the specimen 39 formed using an optical projection-exposure device. The relative positions of the dot-pattern 70a and of the line-and-space patterns 70b, 70c desirably are known in advance. Whereas, in this embodiment, the line-and-space patterns 70b, 70c are used as a fiducial mark for the off-axis optical system, other marks can be used for such a purpose so long as the marks are configured as a geometric pattern suitable for detection by the off-axis optical system. For example, the fiducial mark for the off-axis optical system alternatively can be any of various marks suitable for use with a CPB projection-optical system (e.g., as used in CPB projection microlithography). Further alternatively, the fiducial mark can be the dot-pattern 70a formed on the cold cathode. In the latter instance, the line-and-space patterns 70b, 70c on the fiducial plate 70 would be unnecessary. Alignment of the CPB-optical system using the cold cathode of this embodiment is described with reference to FIGS. 7 and 8. First, as shown in FIG. 7, the X-stage 35 and the Y-stage 37 are moved by means of the X-stage driver 36 and the Y-stage driver, respectively, to situate the dot-pattern 70a on the fiducial plate 70 beneath the cathode lens 51 of the CPB-optical system. Image information concerning the dot-pattern 70a is obtained using the detector 52 that generates a corresponding signal that is routed to the CPU 63. Meanwhile, stage-position data as obtained by the X-interferometer 67 and the Y-interferometer are routed to the X-stage driver 36 and the Y-stage driver. Based on such information, the position of the dot-pattern 70a is adjusted so as to place the dot-pattern 70a in accurate alignment with the optical axis of the CPB-optical system. Next, as shown in FIG. 8, the X-stage 35 and the Y-stage 37 are moved so as to situate the line-and-space patterns 70b, 70c beneath the objective lens 76 of the off-axis optical system. Image data concerning the line-and-space patterns 70b, 70c are detected by the CCD 79 that generates corresponding signals that are routed to the CPU 63. Meanwhile, stage-position data obtained by the X-interferometer 67 and the Y-interferometer are routed to the X-stage driver 36 and Y-stage driver, respectively. The positions of the line-and-space patterns 70b, 70c are adjusted so as to be aligned accurately with corresponding patterns defined on the index plate 77 in the off-axis optical system. Since the relative positional relationships of the dot-pattern 70a with the line-and-space patterns 70b, 70c are known in advance, the distance between the optical axis of the CPB-optical system and the optical axis of the off-axis optical system, i.e., the so-called “baseline” BL, is found by executing the procedure described above. After the baseline BL has been determined, the X-stage 35 and the Y-stage 37 are moved, thereby situating the specimen 39 beneath the objective lens 76 of the off-axis optical system. Data concerning the image of the alignment marks on the specimen 39 (as detected by the CCD 79 and routed to the CPU 63) and stage-position information (as detected by the X-interferometer 67 and the Y-interferometer and routed to the CPU 63) are fed back to the X-stage driver 36 and the Y-stage driver. Thus, the alignment marks on the specimen 39 are aligned with the pattern on the index plate 77 in the off-axis optical system. The position of the specimen 39 on the X-stage 35 is checked at this time because the relative positional relationship between the specimen 39 and the alignment marks on the specimen 39 is already known. Finally, the X-stage 35 and the Y-stage 37 are moved according to the baseline BL previously determined so as to situate the specimen 39 at the irradiation position of the CPB-optical system. Then, the specimen 39 can be observed and inspected. Since the respective optimum fiducial marks can be selected for the CPB-optical system and the off-axis optical system using this embodiment, as described above, it is possible to observe and inspect the specimen 39 accurately and quickly. Whereas the fiducial mark for the off-axis optical system in this embodiment desirably is defined as a geometric pattern (e.g., line-and-space patterns 70b, 70c, formed on the fiducial plate 70), a suitable alternative is, e.g., a surface-emitting laser that forms a geometric pattern. In the alternative situation, the illumination system shown in FIG. 7 (i.e., the light source, optical fiber 71, lens 72, and half-mirror 73) would be unnecessary. By increasing its imaging magnification, the off-axis optical system of this embodiment can be used not only as a simple alignment microscope but also as a viewing microscope. This embodiment is shown in FIG. 9, schematically depicting the CPB-optical system of this embodiment. In this embodiment, a mapping electron microscope is used instead of the optical microscope in Representative Embodiment 2. A dot-pattern 70a is formed on a cold cathode on the fiducial plate 70 (see preceding embodiment) and is used as a common fiducial mark for the CPB-optical system and for the off-axis optical system. In FIG. 9, components that are the same as in the second representative embodiment have the same reference designators and are not described further. An alignment beam T emitted from the dot-pattern 70a sequentially passes through a cathode lens 82 and an imaging-optical system to the detector 52′. The imaging-optical system, like the secondary optical system in the CPB-optical system, comprises an aperture stop AS3, a front imaging lens group 83, a field-stop FS3, and a rear imaging lens group 84. The alignment beam T incident to the detector 52′ forms an image of the dot-pattern 70a by means of the imaging-optical system. The image of the dot-pattern 70a is converted by the detector 52′ into a corresponding optical image. The optical image passes through a relay lens 85 and enters a pickup element 61′. Light incident to the pickup element 61′ is converted into a corresponding photoelectric signal that is routed to a controller 62. The controller 62 converts the photoelectric signal into a corresponding electrical signal that is routed to the CPU 63. As data concerning the dot-pattern 70a detected by the pickup element 61′ is routed to the CPU 63, stage-position data obtained by the X-interferometer 67 and the Y-interferometer are routed back to the X-stage driver 36 and the Y-stage driver. Responsive to such feedback, the position of the dot-pattern 70a is thus adjusted to align accurately with the optical axis of the off-axis optical system. The baseline BL is found and the specimen 39 is observed and inspected in the same manner as described in the second representative embodiment. This embodiment allows respective optimum fiducial marks to be selected for the CPB-optical system and the off-axis optical system. Hence, this embodiment allows the specimen 39 to be observed and inspected accurately and quickly. Whereas a mapping electron microscope was used as the off-axis optical system in this embodiment, a scanning electron microscope, for example, alternatively can be used. Alignment and review can be performed, with this embodiment, in a manner similar to the second representative embodiment. When performing such review, high magnification easily can be obtained if a scanning electron microscope were used as the off-axis optical system. Whereas a dot-pattern 70a on the fiducial plate 70 desirably is used as the fiducial mark for the CPB-optical system in this embodiment, a line-and-space pattern, a cross pattern, or an L-shaped mark alternatively can be used to advantage. In this and the preceding embodiment, the positions of the CPB-optical system and the off-axis optical system desirably are stationary, with the specimen 39 and fiducial plate 70 being moved relative to the CPB-optical system and the off-axis optical system by moving the X-stage 35 and the Y-stage 37. Alternatively, the X-stage 35 and the Y-stage 37 can be held stationary while the CPB-optical system and off-axis optical system are moved. Whereas the trajectory of the primary beam S was bent by a Wien filter (E×B) 42, and whereas the secondary beam K proceeded straight through the Wien filter 42, this embodiment alternatively can be configured such that the primary beam S proceeds straight through the Wien filter 42 and the trajectory of the secondary beam K is bent. Whereas an electron beam was utilized in each of this and the preceding embodiments, it will be understood that another type of charged particle beam, such as an ion beam, alternatively can be used. A CPB-optical system according to either this or the preceding embodiment easily can be applied to microlithographic projection-exposure equipment and the like for use in manufacturing semiconductor devices, in addition to stand-alone observation apparatus or inspection apparatus. In this embodiment of a CPB mapping projection-optical system, as in the first representative embodiment, the primary optical system, the secondary optical system, and the cathode lens can be adjusted independently of each other by use of a self-emitting adjustment-beam source, such as a cold cathode, on or near the specimen surface. This embodiment is depicted schematically in FIG. 10, in which components that are the same as in the preceding embodiments have the same reference designators and are not described further. The cold cathode 38 used in this embodiment desirably is a so-called “self-emitting” beam source that emits an electron beam having a low kinetic energy (peak energy is generally 10 eV or less in this embodiment). The magnitude of the kinetic energy is at or near the magnitude of the kinetic energy of the secondary beam K (generally less than 10 eV in this embodiment) emitted from the object surface of the specimen 39, as previously described. The CPU 63 in this embodiment generates a control signal that is routed to the first power controller 65, a second power controller 66, and an electromagnetic-field controller 69. The first power controller 65 controls electrical energy applied to respective components in the primary optical system; the second power controller 66 controls the respective electrical energies applied to the cathode lens 51, the first aligner 50, and components in the secondary optical system; and the electromagnetic-field controller 69 controls the electromagnetic field generated within the Wien filter (E×B) 42 by controlling the voltage and current applied to the Wien filter 42. In addition, the respective electrical energy applied to these various components can be turned ON and OFF selectively by external commands from the operator or other suitable means. The method for adjusting a CPB mapping projection-optical system according to this embodiment is now described. For such a purpose, the cold cathode 38 desirably forms a dot-pattern. First, the optical axis of the secondary optical system is adjusted using the dot-pattern of the cold cathode 38. In FIG. 10, the X-stage 35 and the Y-stage 37 are actuated to move by the respective X-stage driver 36 and the Y-stage driver (not shown) so as to situate the cold cathode 38 beneath the cathode lens 51. Next, the cathode lens 51 is energized (i.e., a voltage is impressed on the cathode lens 51) while the other lenses are turned OFF. The adjustment beam T emitted from the cold cathode 38 enters the cathode lens 51. As it passes through the cathode lens 51, the adjustment beam T is subjected to the electrical field generated by the cathode lens 51. After passing through the cathode lens 51, the adjustment beam T, like the secondary beam K, passes sequentially through the first aligner 50, the aperture stop AS, the Wien filter 42, and the secondary optical system. The adjustment beam T then enters the detector 52. Data generated by the detector 52 as the detector receives the adjustment beam T are routed sequentially to the relay lens 60, the pickup element 61, the controller 62, and the CPU 63. The CPU generates a corresponding signal that is routed to the display 64 that displays a corresponding video image of the dot-pattern. Since, at this step in the procedure, no electrical energy is being applied to any lens other than the cathode lens 51, the only force to which the adjustment beam T is subjected as it propagates to the detector 52 is the electrical field in the cathode lens 51. The image of the dot-pattern on the detector surface of the detector 52 is defocused by causing the voltage of the cathode lens 51 to fluctuate in an AC fashion (“wobble”). If the dot-pattern is not on the optical axis of the cathode lens 51, then the image of the dot-pattern on the display 64 will move within a plane perpendicular to the optical axis together with the defocusing. The X-stage 35 and the Y-stage 37 are shifted adjustably until the image of the dot-pattern on the display 64 no longer moves, regardless of defocusing. The position of the dot-pattern at which no motion is evident on the display 64 is the position at which the dot-pattern is on the optical axis of the cathode lens 51. This completes adjustment of the optical axis of the cathode lens 51. Next, electrical energy is applied also to the front imaging lens group 53 as well as on the cathode lens 51. At this time, the parameters of applied electrical energy are established so that the image of the dot-pattern of the cold cathode 38 is formed on the detector 52; as with the adjustment of the optical axis of the cathode lens 51, the electrical energy applied to the first aligner 50 is adjusted, while fluctuating the voltage in an AC fashion, until the displayed image of the dot-pattern no longer moves. Thus, the optical axis of the front imaging lens group 53 is aligned with the optical axis of the cathode lens 51. Next, in addition to the cathode lens 51 and front imaging lens group 53, electrical energy is also applied to the rear imaging lens group 54. At this time, the parameters of applied electrical energy are established so that the image of the dot-pattern of the cold cathode 38 is formed on the detector 52. The electrical energy applied to the second aligner 57 is adjusted, while fluctuating the voltage in an AC fashion, until the displayed image of the dot-pattern no longer moves. Thus, the optical axis of the rear imaging lens group 54 is aligned with the optical axis of the cathode lens 51 and front imaging lens group 53. Finally, the electrical energy applied to the third aligner 58 is adjusted to move the image of the dot-pattern to the center of the detector 52 to permit alignment of the center of the detector 52 with the optical axis. Thus, the optical axes of the cathode lens 51 and of the secondary optical system are aligned with each other. The adjustment beam T can be accelerated by providing a potential difference between the cold cathode 38 and an electrode positioned object-wise of the cathode lens 51 by means of an acceleration power supply 68. Whereas the optical axis of the secondary optical system was adjusted in this embodiment by forming a dot-pattern on the cold cathode 38, various aberrations can be analyzed similarly using a dot-pattern. This is performed by detecting a video image of a defocused dot-pattern image or obtaining an intensity distribution of the dot-pattern image at the detector 52. Spherical aberration in the secondary optical system can be measured and corrected by using a line-and-space pattern rather than a dot-pattern on the cold cathode 38. Distortion in the secondary optical system can be measured and corrected by using a cross mark or an L-shaped mark on the cold cathode 38. After the optical axes of the cathode lens 51 and the secondary optical system have been adjusted, the electron gun 41 and primary optical system can be adjusted using steps similar to those described above. After the electron gun 41 and primary optical system have been adjusted, the Wien's condition of the Wien filter 42 can be adjusted. As discussed above, the Wien's condition is the condition under which the primary beam S is deflected at a desired angle as the primary beam passes through the Wien filter 42, while the secondary beam K proceeds straight through the Wien filter 42. The Wien's condition of the Wien filter 42 can be adjusted using the cold cathode 38. To such end, in FIG. 10, the cold cathode 38 is situated beneath the cathode lens 51 by moving the X-stage 35 and the Y-stage 37 using the X-stage driver 36 and Y-stage driver, respectively. The Wien's condition of the Wien filter 42 relative to the secondary optical system, i.e., the condition under which the secondary beam K proceeds straight through the Wien filter 42, is found by turning the voltage and current applied to the Wien filter 42 ON and OFF. Typically, the voltage and current applied to the Wien filter 42 are set so that the position of the dot-pattern image of the cold cathode 38 observed on the display 64 when voltage and current are not being applied to the Wien filter 42 is aligned with the position of the image of the cold cathode 38 when voltage and current are being applied to the Wien filter. Finally, a fine adjustment can be performed using the aligners 46, 47 so that the optical axis of the secondary optical system and the optical axis of the primary optical system are aligned with each other between the Wien filter 42 and the specimen 39 whenever the set voltage and current are applied to the Wien filter 42. Thus, with this embodiment, the Wien's condition of the Wien filter 42 can be adjusted easily. In this way, the illumination field of the primary optical system and the observation field of the secondary optical system are aligned quickly and accurately with each other, allowing an excellent video image to be obtained from the CPB-optical system. Whenever a voltage and current are applied to the Wien filter 42, aberrations such as astigmatism and the like normally are produced in the secondary optical system. Consequently, it is desirable also to adjust the stigmators 55, 56 (to provide correction of such aberrations) at the same time the Wien's condition is set. Thus, imaging parameters can be maintained linking the lens action produced at this time and lens conditions in the secondary optical system. Typically, the respective voltage and current applied to the Wien filter 42 as well as the electrical energy applied to the stigmators 55, 56, the cathode lens 51, the front imaging lens group 53, and the rear imaging lens group 54 are adjusted simultaneously so that the position of the cold cathode 38 image on the display 64 does not fluctuate, regardless of whether power applied to the Wien filter 42 is ON or OFF. Whereas, in this embodiment, the trajectory of the primary beam S is bent by the Wien filter 42 while the secondary beam K proceeds in a straight path through the Wien filter, the system alternatively can be configured such that the primary beam S proceeds straight and the trajectory of the secondary beam K is bent. Whereas an electron beam is used as the charged particle beam in this embodiment, any of various other charged particle beams (e.g., ion beam) alternatively can be used. Whereas a cold cathode 38 is used in this embodiment as the source of the adjustment beam, a separate electron gun alternatively can be used. Whereas the adjustment order in this embodiment proceeds first with the cathode lens 51, then the secondary optical system, then the primary optical system, and then the Wien filter 42, the order can be changed, if desired, to achieve the same goal. An exemplary alternative order is adjusting the cathode lens 51 first, then adjusting the primary optical system, then the secondary optical system, and then the Wien filter 42. The CPB-optical system of this embodiment is a so-called “surface-to-surface” CPB-optical system that illuminates the surface of the specimen 39 using an electron beam from a beam source and forms an image thereof at an image surface. However, this CPB-optical system also can be utilized as a semiconductor exposure device, or the like. This embodiment is mainly directed to evaluation charts for use with a mapping CPB microscope such as any of the embodiments described above. Evaluation charts according to this embodiment do not require adjustment of the optical axis of the illumination optical system. Also, evaluation charts according to this embodiment exhibit a stable distribution of kinetic energy of an electron beam emitted from the evaluation chart. In a mapping CPB microscope such as according to any of the preceding embodiments, it will be recalled that a “primary beam” (or “irradiation beam”) S passing through a “primary optical system” (or “irradiation-optical system”) irradiates the surface of the specimen 39. Such irradiation of the specimen 39 generates a “secondary beam” (or “observation beam”) K that passes through a “secondary optical system” (or “mapping optical system”) to form an image of the irradiated surface. An evaluation chart according to this embodiment is especially adapted to be placed at the position of the specimen 39. The evaluation chart emits an “evaluation beam” E used for evaluating and adjusting the secondary optical system. For such purposes, it is desirable that the kinetic energy of the inspection beam E be essentially equal to the kinetic energy of the secondary beam K. It is also desirable that the emission profile of the evaluation beam E have any of a dot profile, line profile, or plane profile. The evaluation chart can be formed on a hot-electron emitter, as shown for example in FIGS. 11 and 12. The FIG. 11 configuration is an evaluation chart situated on a hot-electron emitter 91. A gate electrode 95 (desirably made of aluminum Al) and an n+-Si layer 96 are formed on the surface of the hot-electron emitter 91. Multiple arrays of emitting line features 97 are formed on the n+-Si layer 96. The pitch of each array of line features 97 changes step-wise in a meridional direction and in a sagittal direction. The pitch of the line features 97 ranges from approximately 100 nm to several μm in this embodiment. Each line feature 97 spontaneously emits an electron beam, which collectively constitute the evaluation beam E. In other words, each individual line feature 97 corresponds with an electron-emission surface of the hot-electron emitter 91. The size and pitch of the line features 97 can be made as small as, e.g., several tens of nanometers. (Such resolution is obtainable by electron-beam microlithography.) The evaluation chart of FIG. 11 is disposed at the position of the specimen surface in a CPB mapping microscope as described above, and used to determine the resolution of the mapping optical system. In normal use of a CPB mapping microscope for observation of a specimen, either the specimen 39 is grounded or the specimen is maintained at a constant potential. Hence, it is desirable with the hot-electron emitter 91 to cover completely the surface of the evaluation chart with the gate electrode 95 or with another surficial metallic film to facilitate maintaining a predetermined potential. By either grounding the gate electrode 95 or maintaining it at a constant potential, actual observation conditions are reproduced during use of the evaluation chart. A representative internal structure of the hot-electron emitter 91 is shown in FIG. 12, which is an oblique perspective view of one of the line features 97 of the evaluation chart of FIG. 11 with part of the perimeter sectioned. A rear electrode 92 (desirably made of aluminum) is formed on the rear surface of a silicon (Si) substrate 93. The rear electrode 92 desirably is grounded during use. An insulating layer 94 (desirably made of SiO2) is formed on the upper surface of the substrate 93. By way of example, the thickness d4 of the insulating layer 94 is, e.g., 500 nm. A groove having a width “r6” of, e.g., 100 nm is formed by electron-beam microlithography in the insulating layer 94. Also by way of example, the thickness of the remaining insulating layer, i.e., the dimension “h6” between the groove and the upper surface of the substrate 93, is 10 nm. The n+-Si layer 96, having an exemplary thickness “d6” of 20 nm, is formed on top of the groove. The gate electrode 95 is formed over the insulating layer 94, leaving only the opening of the groove in the n+-Si layer 96. Whenever a bias voltage is applied to the gate electrode 95 by a power supply VD, an evaluation electron beam E is emitted from the groove. The evaluation electron beam E has a transverse profile corresponding with the shape of the opening of the groove (i.e., the beam E has a transverse profile corresponding with the shape of the line feature 97). The distribution of the emitted electrons in the evaluation beam E can be adjusted by changing the thickness h6 of the insulating layer 94 or by changing the voltage applied to the gate electrode 95. The evaluation chart of FIGS. 11 and 12, as described above, is a so-called “self-emitting” evaluation chart. For use in measuring and adjusting the performance of primary and secondary optical systems (as described generally in the preceding embodiments), the hot-electron emitter 91 is placed at the position of the specimen 39. Thus, the resolution of the primary and second optical systems can be measured and adjusted without having to use the primary optical system to produce a primary beam. In addition, image distortion produced by the secondary optical system can be evaluated by measuring the amount of distortion, of the line-feature pattern over the entire surface of the evaluation chart, produced by the secondary optical system alone. Whereas an evaluation chart comprising the line features 97 is used in this embodiment for evaluating and adjusting the optical performance of a CPB mapping microscope, the optical axis of the secondary optical system can be adjusted if a dot-pattern were to be used as the inspection chart (as described in the preceding embodiments). Further alternatively, various aberrations in the mapping optical system can be evaluated using a planar pattern, such as a cross pattern or a pattern of L-shaped features. If required, a composite chart can be used in which variously shaped features are used. Reference is now made to FIGS. 13 and 14, which depict alternative hot-electron emitters. FIG. 13 schematically depicts a GaAs Schottky junction emitter. A p+-GaAs layer 115 is formed on one surface of a p-GaAs substrate 114, and a rear metal electrode 102 (desirably aluminum) having a thickness of, e.g., 10 nm is formed on the other surface of the p-GaAs substrate 114. A p+-GaAs field 113 (having a diameter of, e.g., several micrometers) and an n+-GaAs field 112 are formed on specific regions of the p-GaAs substrate 114 to form Schottky junctions. Whenever a reverse bias is impressed on the rear electrode 102 and on an emitter electrode 110, cascade multiplication is induced. Some of the resulting current that flows through the junction is emitted into a vacuum as the evaluation electron beam E. Turning now to FIG. 14, a MOS-type emitter is shown schematically. In this embodiment, an insulating film 117 (desirably SiO2, approximately 10-nm thick) is formed by thermal oxidation on the surface of an n-Si substrate 118. Atop the insulating film 117 is formed a gate electrode 116 (desirably made of aluminum or amorphous silicon, and having about the same thickness as the insulating film 117). A rear metal electrode 102 (desirably aluminum) is formed on the rear surface of the substrate 118. Whenever a normal bias is impressed on the rear electrode 102 and the gate electrode 116, an electron beam E is emitted. In the hot-electron emitters of FIGS. 13 and 14, the peak value of kinetic energy in the kinetic-energy distribution of the evaluation beam E is zero to several eV and the surface potential is held at a constant value. Such a kinetic energy of the evaluation beam is essentially equal to the kinetic energy of a secondary beam emitted from the specimen in the CPB mapping microscope. It is possible to bring the kinetic energy of the evaluation beam E even closer to the kinetic energy of the secondary beam by adjusting the structural constants, bias, and gate voltage of the emitter. Furthermore, since the surface potential of the emitter is constant, the emitter imparts no effect on the imaging performance of the secondary optical system. Thus, with such emitters, the optical performance of the secondary optical system of a CPB mapping microscope can be evaluated without having to utilize the primary optical system. Furthermore, for example, by making the kinetic energy of the electron beam emitted from the emitter variable, it is possible to evaluate separately, in a quantitative manner, chromatic aberration exhibited by the secondary optical system. Whereas the invention has been described in connection with multiple representative embodiments, it will be understood that the invention is not limited to those embodiments. On the contrary, the invention is intended to encompass all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
	abstract	A radiation resistant clothing includes a first radiation resistant layer for directly reflecting electromagnetic radiation (EMR) and a second radiation resistant layer for absorbing EMR which penetrates through or under the edges of clothing worn over the human body. The second radiation resistant layer is positioned on an inside of the first radiation resistant layer and has radiation absorbing material which dissipates indirect EMR in the form of heat or other energy.
	claims	1. A method of determining crack locations associated with a tubular member, the method comprising:locating a set of stress corrosion cracking indicators associated with a tubular member;locating a set of low-level corrosion indicators associated with a tubular member;comparing locations of the set of stress corrosion cracking indicators with locations of the set of low-level corrosion indicators;establishing a subset of stress corrosion cracking indicators and a subset of low-level corrosion indicators when the location of any of the set of stress corrosion cracking indicators is located within a first preselected distance from any of the set of low-level corrosion indicators;locating a set of soil characterization indicators associated with the tubular member;comparing locations of the set of soil characterization indicators with locations of the subset of stress corrosion cracking indicators and locations of the subset of low-level corrosion indicators;establishing a plurality of predictor stress corrosion cracking indicators, a plurality of predictor low-level corrosion indicators, and a plurality of predictor soil characterization indicators when the location of any of the set of soil characterization indicators is located both within a second preselected distance from any of the subset of stress corrosion cracking indicators and within a third preselected distance from any of the subset of low-level corrosion indicators; andpredicting at least one of a plurality of locations associated with the tubular member susceptible to stress corrosion cracking responsive to at least two of the plurality of predictor indicators. 2. A method as defined in claim 1, wherein the set of stress corrosion cracking indicators comprise a crack-like feature associated with the tubular member, wherein the set of low-level corrosion indicators comprise a low-level metal loss feature associated with the tubular member, wherein the set of soil characterization indicators comprise characteristics selected from the group consisting of: chemical content, pH level, and terrain elevation, and wherein the step of predicting includes selecting the locations having a high probability of the presence of stress corrosion cracking associated with the tubular member thereby minimizing false impressions of stress corrosion cracking due to anomalies associated with the tubular member. 3. A method as defined in claim 2, further comprising the step of evaluating the tubular member to gather data relating to the tubular member, wherein the evaluating includes using tools selected from the group consisting of: elastic wave, electro-magnetic acoustic, and digital magnetic flux leakage, and wherein a first, second, and third preselected distance each comprises directional components of both a preselected longitudinal distance and a preselected radial distance. 4. A method of determining crack locations associated with a tubular member, the method comprising:evaluating the tubular member to gather data relating associated with the tubular member;locating a plurality of stress corrosion cracking indicators associated with the tubular member;locating a plurality of low-level corrosion indicators associated with the tubular member;locating a plurality of soil characterization indicators associated with the tubular member;establishing a plurality of predictor stress corrosion cracking indicators, a plurality of predictor low-level corrosion indicators, and a plurality of predictor soil characterization indicators when any of the plurality of stress corrosion cracking indicators, any of the plurality of low-level corrosion indicators and any of the plurality of soil characterization indicators are located within a preselected distance from each other; andpredicting a plurality of locations on the tubular member susceptible to stress corrosion cracking responsive to at least two of the plurality of predictor indicators. 5. A method as defined in claim 4, wherein the predicting indicates a high probability of the presence of stress corrosion cracking associated with the tubular member thereby minimizing false impressions of stress corrosion cracking due to manufacturing or construction anomalies on the tubular member. 6. A method as defined in claim 4, wherein the stress corrosion cracking indicators comprise a crack-like feature associated with the tubular member, wherein the low-level corrosion indicators comprise a low-level metal loss feature associated with the tubular member, and wherein the soil characterization indicators comprise characteristics selected from the group consisting of: chemical content, pH level, and terrain elevation. 7. A method as defined in claim 4, wherein preselected distance comprises directional components of both a preselected longitudinal distance and a preselected radial distance. 8. A method as defined in claim 7, wherein the preselected longitudinal distance is within 4 inches and the preselected radial orientation. 9. A method as defined in claim 7, wherein the preselected longitudinal distance is within 20 inches and the preselected radial orientation. 10. A method as defined in claim 4, wherein the evaluating includes using tools selected from the group consisting of: elastic wave technology, electro-magnetic acoustic technology, and digital magnetic flux leakage technology. 11. A system to determine crack locations on a tubular member, the system comprising:a comparator to compare locations of a set of stress corrosion cracking indicators associated with a tubular member with locations of a set of low-level corrosion indicators associated with the tubular member to thereby establish a subset of stress corrosion cracking indicators and a subset of low-level corrosion indicators, responsive to comparing the sets of indicators, when the location of any of the set of stress corrosion cracking indicators is located within a first preselected distance from any of the set of low-level corrosion indicators, the comparator further comparing locations of a set of soil characterization indicators associated with the tubular member with locations of the subset of stress corrosion cracking indicators and locations of the subset of low-level corrosion indicators; anda predictor to predict that a segment of the tubular member is susceptible to stress corrosion cracking, responsive to comparing the set of soil characterization indicators with the subsets of indicators, when any of the set of soil characterization indicators is located both within a second preselected distance from any of the subset of stress corrosion cracking indicators and within a third preselected distance from any of the subset of low-level corrosion indicators. 12. A system as defined in claim 11, wherein the predictor indicates a high probability of the susceptibility of stress corrosion cracking associated with the tubular member thereby minimizing false impressions of stress corrosion cracking due to manufacturing or construction anomalies associated with the tubular member. 13. A system as defined in claim 11, wherein the stress corrosion cracking indicators comprise a crack-like feature associated with the tubular member, and wherein the low-level corrosion indicators comprise a low-level metal loss feature associated with the tubular member, wherein the soil characterization indicators comprise characteristics selected from the group consisting of: chemical content, pH level, and terrain elevation. 14. A system as defined in claim 13, wherein preselected distance comprises directional components of both a preselected longitudinal distance and a preselected radial distance. 15. A system as defined in claim 14, wherein the preselected longitudinal distance is within 4 inches and the preselected. 16. A system as defined in claim 14, wherein the preselected longitudinal distance is within 20 inches and the preselected. 17. A system as defined in claim 14, wherein the system includes at least one tool selected from the group consisting of: elastic wave, electro-magnetic acoustic, and digital magnetic flux leakage. 18. A system to determine crack locations associated with a tubular member, the system comprising:a comparator to compare locations of a set of stress corrosion cracking indicators associated with the tubular member with locations of a set of low-level corrosion indicators associated with the tubular member to thereby establish a subset of stress corrosion cracking indicators and a subset of low-level corrosion indicators, responsive to comparing the sets of indicators, when the location of any of the set of stress corrosion cracking indicators is located within a first preselected distance from any of the set of low-level corrosion indicators, the comparator also being positioned to compare locations of a set of soil characterization indicators associated with the tubular member with locations of the subset of stress corrosion cracking indicators and locations of the subset of low-level corrosion indicators; anda confirmer to confirm a presence of stress corrosion cracking in a segment of the tubular member, responsive to comparing the set of soil characterization indicators with the subsets of indicators, when any of the set of soil characterization indicators is located both within a second preselected distance from any of the subset of stress corrosion cracking indicators and within a third preselected distance from any of the subset of low-level corrosion indicators. 19. A system as defined in claim 18, wherein the confirmer also indicates a high probability of the presence of stress corrosion cracking in the tubular member thereby minimizing false impressions of stress corrosion cracking due to manufacturing or construction anomalies on the tubular member. 20. A system as defined in claim 18, wherein the stress corrosion cracking indicators comprise a crack-like feature associated with the tubular member, wherein the low-level corrosion indicators comprise a low-level metal loss feature associated with the tubular member, and wherein the soil characterization indicators comprise characteristics selected from the group consisting of: chemical content, pH level, and terrain elevation. 21. A system as defined in claim 18, wherein preselected distance comprises directional components of both a preselected longitudinal distance and a preselected radial distance. 22. A system as defined in claim 21, wherein the preselected longitudinal distance is within 20 inches and the preselected radial distance is within 60 degrees. 23. A system as defined in claim 18, wherein the indicators of the system are determined at least one using tool selected from the group consisting of: elastic wave, electro-magnetic acoustic, and digital magnetic flux leakage. 24. A method of determining crack locations associated with a pipeline body wall, the method comprising:detecting a set of crack-like features associated with the pipeline;detecting a set of low-level metal loss corrosions;comparing locations of the set of crack-like features with locations of the set of low-level metal loss corrosions;establishing a subset of crack-like features and a subset of low-level metal loss corrosions, responsive to comparing the set of crack-like features with the set of low-level metal loss corrosions, when the location of any of the set of crack-like features is located within a first preselected distance from any of the set of low-level metal loss corrosions;detecting a set of soil characterization models;comparing locations of the set of soil characterization models with locations of the subset of crack-like features and locations of the subset of low-level metal loss corrosions; andconfirming with high probability the presence of stress corrosion cracks associated with the pipeline body wall when the location of any of the set of soil characterization models is located both within a second preselected distance from any of the subset of crack-like features and within a third preselected distance from any of the subset of low-level metal loss corrosions. 25. A method of predicting a location of stress crack corrosion in a gas pipeline, the method comprising:integrating in-line pipeline wall inspection results, in-line low level external metal loss, external corrosion analysis results, and soil characterization model results; andcomparatively evaluating the in-line pipeline wall inspection results, the in-line low level external metal loss, the external corrosion analysis results, and the soil characterization model results to determine with a high confidence level whether actual stress corrosion cracking exists at a physical gas pipeline segment location responsive to the integrating.
	description	The present invention relates to a mass which is specially designed for the manufacture of high-capacity neutron radiation protection products, such as concrete, bricks, tiles and mortars. The object of the invention is to obtain a mass having a high homogeneity, with an optimum barrier effect against neutrons of various energies, allowing a significant reduction of the thickness of shielding barriers in comparison with standard materials for achieving the same barrier effect against said radiation. It is also an object of the invention to cause and/or increase the neutron absorption effect of this material in various energies, and to eliminate or significantly reduce the effect of neutron scattering indoors, thus that in the case of the cancer treatment bunkers, it would mean that the patient would only receive the neutrons received directly from the main beam, those received by the scatter effect being eliminated. The electronics and room control systems also take advantage of this feature, and also a significant reduction in the shielding of the bunker door is allowed, among other beneficial aspects. The invention is applicable to any radiological protection system, such as containers and/or mobile barriers of radioactive facilities, radiotherapy bunkers, or any facility where the existence of neutrons is expected. Concrete with capacity of radiation protection has, in addition to the usual cement components, water and chemical additives which vary according to the desired characteristics, such as resistance, setting time, protection against freezing, assurance of the absence of cracking, marine environment, etc., and an aggregate that makes them different from conventional concrete. The problem posed by this type of concrete is that, in order to provide good radiation protection properties, a considerable wall thickness is required; accordingly, a negative impact on weight, space, and cost arises, since the hydrogen content in such concrete is usually low. In an attempt to solve this problem, Spanish patent application number P 200900481 and publication number ES 2 344 290 is known; this document describes a mass for the manufacture of products with a high neutron radiation protection capacity, said mass, as any conventional concrete, being formed by cement, aggregates, water and chemical additives that change the characteristics of the concrete, with the particularity that said mass uses Colemanite with a very continuous grain size as an aggregate for obtaining a mass with a perfect homogeneity, thus allowing for obtaining a barrier effect against neutron radiation allowing to significantly reduce the wall thickness without diminishing the barrier effect. More specifically, said Patent envisaged the use of Portland cement, water, Colemanite and additives. The applicant of this Patent has discovered that the results obtained with the same can be clearly improved through the use of new components in the mass in question. According to a feature of the invention, the mass comprises, instead of the aforementioned Portland cement, Alumina cement (Al2O3). The Alumina content in the cement is comprised between 36% and 45%, and it can reach 70%, depending on the availability of this type of product, and controlling the capacity of reaction with calcium sulfate. According to another feature of the invention, the mass further comprises a new component that is introduced, particularly anhydrous calcium sulfate (CaSO4). This sulfate must have a high degree of purity. The use of Colemanite aggregate (Ca2B6O11 5H2O), which is a calcium borate, is maintained, and also the chemical additives needed for a proper production and installation or casting are maintained. The new material, i.e. the new composition of the mass, has the following volumetric distribution: Alumina cement between 4 and 5%. Water between 17 and 18%. Anhydrous calcium sulfate between 5 and 5.5%. Colemanite between 72 and 73.5%. Additives of the order of 0.02%. From a suitable combination between the cement with a high content of Alumina and the anhydrous calcium sulfate, a quick crystallization of Ettringite (3CaO Al2O3 3CaSo4 32H2O) is obtained, therefore causing a significant increase in the number of hydrogen molecules which is very effective for capturing neutrons, mainly the fast neutrons, absorbing them or thermalizing them, these thermal neutrons being captured by the boron contained in the mixture. In a practical embodiment of the mass or material, the following mixture expressed in volume has been carried out: Alumina cement . . . 4.5% Water . . . 17.5% Anhydrous calcium sulfate . . . 5.23% Colemanite . . . 72.75% Additives . . . 0.02% These figures may suffer a 10% variation either as an increase or as a decrease, depending on the production processes to be used, curing, fraction of the aggregate to be used, and the main objectives such as radiation protection coefficients, mechanical strength of the mass, cracking, etc. In case the granulometric fraction of Colemanite is small in size, specifically when the maximum size of the aggregate in the fraction is less than 8 or 10 mm, dosage variations in the previous formulation may be even greater than 10%, due to the solubility of Colemanite in water. Density is not a parameter pursued in a specific way, and it will be the result of the optimization of the mixture. However it will be around 2.1 Kg/dm3. As previously mentioned, the heavy mass proposed by the invention allows for obtaining concrete for pouring, concrete for bricks, concrete for tiles or dry mortar. The results obtained with the invention are clearly shown in the graphs shown in FIGS. 1 and 2.
	claims	1. A particle beam transport system comprising:a main line configured to transport a particle beam generated by an accelerator outward;a branch line branching from the main line;irradiation equipments provided at respective ends of the branch line and configured to irradiate a patient with the particle beam,wherein at least a part of the main line and the branch line is configured as plural segments; andin each of the segments, constituent components and arrangement of the constituent components are made common, and at least a first bending electromagnet, a focus electromagnet, and a second bending electromagnet among the constituent components are arranged in this order, the focus electromagnet configured to focus an outer diameter of the particle beam by an action of a magnetic field and the bending electromagnet configured to bend a traveling direction of the particle beam by an action of a magnetic field;beam characteristics of the particle beam of each of the plural segments are substantially equal at both ends. 2. The particle beam transport system according to claim 1,wherein in each of the plural segments a betatron function β (βx, βy) in the orthogonal direction (x, y) of the passing particle beam is equal at both ends. 3. The particle beam transport system according to claim 1,wherein each of the plural segments includes a beam measuring component; andthe beam measuring component is provided at a most upstream portion or a most downstream portion of each of the plural segments. 4. The particle beam transport system according to claim 1,wherein each of the plural segments includes a beam-trajectory correction electromagnet. 5. The particle beam transport system according to claim 1, further comprising a scatterer provided on the main line between the accelerator and one of the plural segments that is closest to the accelerator,the scatterer is configured to cause multiple scattering of the particle beam; anda cross-sectional shape of the particle beam at both ends of each of the plural segments is adjusted to be substantially circular. 6. The particle beam transport system according to claim 1,wherein phase difference of the particle beam between both ends of each of the plural segment is adjusted to be an integral multiple of 180 degrees. 7. The particle beam transport system according to claim 1,wherein the plural segments constitute the respective ends of the branch line and are connected to respective irradiation equipments. 8. A segment of a particle beam transport system that includes a main line transporting a particle beam generated by an accelerator outward, a branch line branching from the main line, and irradiation equipments provided at respective ends of the branch line and configured to irradiate a patient with the particle beam, the segment being used for the particle beam transport system by being connected to at least one segment of same configuration and comprising:an entrance on which the particle beam is made incident;a passage through which the particle beam made incident from the entrance advances; andan exit from which the particle beam having advanced through the passage is emitted,wherein plural magnets are arranged in such a manner that beam characteristics of the particle beam are substantially equal at the entrance and at the exit,in the segment, constituent components and arrangement of the constituent components are made common, and at least a first bending electromagnet, a focus electromagnet, and a second bending electromagnet among the constituent components are arranged in this order, the focus electromagnet configured to focus an outer diameter of the particle beam by an action of a magnetic field and the bending electromagnet configured to bend a traveling direction of the particle beam by an action of a magnetic field.
	abstract	Methods and systems for estimating peak location on a sampled surface (e.g., a correlation surface generated from pixilated images) utilize one or more processing techniques to determine multiple peak location estimates for at least one sampled data set at a resolution smaller than the spacing of the data elements. Estimates selected from the multiple peak location estimates are combined (e.g., a group of estimates is combined by determining a weighted average of the estimates selected for the group) to provide one or more refined estimates. In example embodiments, multiple refined estimates are combined to provide an estimate of overall displacement (e.g., of an image or other sampled data representation of an object).
050874128	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it is seen that the invention is generally referred to by the numeral 10. Nuclear reactor 10 is formed from reactor vessel 12 having primary coolant outlet plenum 14, core barrel 16, fuel elements 18, safety rods 20, and control drums 22. Drives 24 are also provided for safety rods 20 and control drums 22. Instrumentation and power leads enter reactor 10 through head penetration nozzle 26. Nuclear reactor 10 is essentially a conventional nuclear reactor relative to the use of a reactor vessel, fuel elements, safety rods, and control drums with improvements directed toward nuclear reactors intended for applications in outer space. Primary coolant inlet passage 28 is provided on the outer wall of primary coolant outlet plenum 14. As seen in the detail view of FIG. 4A, passage 28 is of a general torus or semicircular shape in the preferred embodiment. As best seen in FIG. 4 and the detail view of FIG. 4B, inlet passage 28 directs the primary coolant to inlet plenum 30 adjacent to distributor plate 32. During auxiliary heat removal gaseous coolant flows into plenum 28 through nozzles 46. As seen in FIG. 1 and 4B, distributor plate 32 is bolted to core barrel 16 and extends across the lower portion of reactor vessel 12 above primary coolant outlet plenum 14. As best seen in the detail views of FIG. 4B and 4C, distributor plate 32 is provided with passageways 34 which direct the primary coolant to a gap 38 between each fuel element housing thimble 36 and the fuel element 18 it surrounds. As seen in FIG. 4C, fuel element housing thimbles 36 and fuel elements 18 are mounted in distributor plate 32 to form gap 38. Fuel elements 18 also extend below distributor plate 32 into primary coolant outlet plenum 14 as seen in FIG. 1, 3, and 4 so that the interior of each fuel element 18 is in fluid communication therewith. The primary coolant flows from gap 38 through porous material 40 as indicated by the arrow in FIG. 4C into center 42 of fuel element 18 and then flows downwardly through fuel element 18 into primary coolant outlet plenum 14. Reactor vessel 12 is provided with nozzles 44 used to insert or drain liquid from the reactor core. During reactor operation the liquid is circulated up through the moderator region bounded by the inside of core barrel 16 and the outside of fuel element housing thimbles 36. As seen in FIG. 3 and indicated by arrows, the liquid then enters circulation pumps 45, is discharged by the pumps into the upper head, and then flows down around and through the control drums 22 in the reflector region bounded by the reactor vessel 12 and the core barrel 16. As seen in FIG. 3A, and indicated by arrows, the liquid then completes its circulation loop by flowing into the moderator region through the passages provided in core barrel 16 at the lower end. As seen in FIG. 3A, fuel element housing thimbles 36 are provided with fins which extend from the thimble outer circumference into the liquid and which serve to conduct heat from the liquid to the primary gaseous coolant flowing inside the thimbles 36. This is accomplished by using a primary coolant that is at a temperature cooler than the liquid moderator when the coolant enters annular gap 38. The primary coolant (cold relative to the moderator) is heated by conduction/convection from the warmer liquid moderator through housing thimble 36. The moderator is heated by absorbed radiation to a dynamic equilibrium temperature higher than that of the coolant. Direct heating of the primary coolant by the fuel elements does not occur until radial passage of the coolant through porous material 40. In conventional terrestrial water moderator reactors, for useful energy production the heat flow is into the liquid moderator at the fuel elements rather than from the liquid as in the reactor of the invention. The liquid moderator/reflector is not in place during manufacture, ground transportation, launch, and disposal, thus enhancing reactor safety since the reactor is kept subcritical. When operation begins, the liquid moderator/reflector is added to reactor vessel 12 through fill/drain nozzles 44 for circulation in the core as described above. The liquid moderator/reflector enables the relatively small amount of fissile material in fuel elements 18 to go critical (become a self-sustaining reaction) in the core and cools the control drums and other system components. In the preferred embodiment, the primary coolant is a gas suitable for such use and the liquid moderator/reflector is water. A gas coolant that is in a cryogenic state, such as hydrogen at minus 400 degrees F., when it enters the inlet of gap 38 is well suited to the heat transfer process of the invention. Other suitable liquid moderator/reflector such as various organic liquids may also be used. An alternative to the preferred approach is shown in FIG. 5 wherein a heat exchanger external to the reactor is provided for supplemental heat removal from the liquid moderator. The liquid moderator circulates through the core from the bottom fill nozzles up through the moderator and reflector regions and into the upper head. From the upper reactor head the liquid exits the core, passes through pump 47, and flows into heat exchanger 48 where it is cooled by the coolant gas before the gas enters the reactor. The liquid moderator then flows from the heat exchanger into the core through the fill/drain nozzles 44. Cooling of the liquid moderator is provided in the core as described in the preferred approach.
	summary
	summary
	claims	1. An X-ray imaging system for displaying an image on a monitor, said system comprising an X-ray source, a collimator, and a masking unit comprising an adjustable shutter located between the X-ray source and the collimator, wherein the masking unit is configured to control the shutter so that part of said image is created at a higher refresh rate using a narrower X-ray beam than the rest of said image, said narrower beam defined by the shutter. 2. A system as in claim 1 wherein said masking unit comprises a plurality of moving coil rotary actuators connected to operate X-ray blocking blades of the shutter. 3. A system as in claim 1 wherein said image part created at the higher refresh rates and the rest of said image created at a lower refresh rate are blended seamlessly by using an image overlap region. 4. A system as in claim 1 wherein the firing of the X-ray source is synchronized to the position of said shutter. 5. A method for improving the resolution of a sequence of X-ray images while reducing the radiation level used, said method comprising the steps of:selecting an area-of-interest in said images;exposing said area-of interest at first refresh rate using a cone of X-rays matched to a size of said area-of-interest; andexposing full images with an X-ray cone covering the full images at a second refresh rate slower than said first refresh rate. 6. A method as in claim 5 wherein the area-of-interest is automatically selected by the system based on rates of change in the images. 7. A method as in claim 5 wherein the area-of-interest is defined automatically based on the change from image to image. 8. A method as in claim 5 wherein the area-of-interest is defined automatically based on the change from image to image, said change excluding periodic change. 9. A method as in claim 5 wherein the area-of-interest is defined automatically based on image to image, said changes excluding periodic changes by synchronizing operation of an X-ray source used to generate said images to a signal derived from said periodic changes. 10. A method as in claim 5 wherein said full image and said area-of-interest are blended seamlessly by using an image overlap region between both images. 11. A method as in claim 5 wherein said full image and said area-of-interest are blended seamlessly by using an image overlap region between both images and the pixel values in the area of interest are affected by both images. 12. A method as in claim 5 wherein both the location and shape of the area-of-interest can be selected by the user. 13. A method as in claim 5 wherein both the location and shape of the area-of-interest are selected automatically. 14. A method as in claim 5 wherein both the location and shape of the area-of-interest can be selected automatically by recognizing features of an object of interest. 15. A method as in claim 5 wherein the refresh rate outside the area-of-interest is automatically selected based on the detected rate of change of the images. 16. A method as in claim 5 wherein the area-of-interest is one of a plurality of areas-of-interest and the method comprises exposing each of said areas-of-interest to a radiation level higher than a radiation level delivered within said images outside of said areas-of-interest. 17. A method according to claim 5 wherein exposing said area-of-interest comprises delivering pulses from a pulsed X-ray source. 18. A method according to claim 17 comprising slaving firing of the pulsed X-ray source to positions of masks that match the cone of X-rays to the size of said area-of-interest. 19. A method according to claim 18 comprising moving the masks continuously. 20. A method according to claim 19 wherein the masks comprise slotted rotary masks and the method comprises adjusting a position of the area-of-interest by advancing or retarding rotation of one of the masks relative to another one of the masks.
	abstract	An x-ray imaging system includes an optical device having at least one point-focusing, curved monochromating optic for directing x-rays from an x-ray source towards a focal point. The at least one point-focusing, curved monochromating optic provides a focused monochromatic x-ray beam directed towards the focal point, and a detector is aligned with the focused monochromatic x-ray beam. The optical device facilitates x-ray imaging of an object when the object is located between the optical device and the detector within the focused monochromatic x-ray beam. In various embodiments: each point-focusing, curved monochromatic optic has an optical surface that is doubly-curved; the optical device facilitates passive image demagnification or magnification depending upon placement of the object and detector relative to the focal point; and at least one second point-focusing, curved monochromatic optic can be employed to facilitate refractive index or polarized beam imaging of the object.
	abstract	Fuel bundles for a nuclear reactor are described and illustrated, and in some cases includes fuel elements each having a first fuel component of recycled uranium, and a second fuel component of at least one of depleted uranium and natural uranium blended with the first fuel component, wherein the blended first and second fuel components have a first fissile content of less than 1.2% wt of 235U. Other fuel bundles are also described and illustrated, and include a first fuel element including recycled uranium, the first fuel element having a first fissile content of no less than 0.72 wt % of 235U; and a second fuel element including at least one of depleted uranium and natural uranium, the second fuel element having a second fissile content of no greater than 0.71 wt % of 235U.
	description	This application claims the benefit of U.S. Provisional Application 60/786,457 titled Tomosurgery, filed Mar. 28, 2006, which is incorporated herein. A portion of the disclosure of this patent document contains material subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. Radiosurgery has typically been performed using a step-and-shoot approach that delivers radiation according to a three dimensional plan of multiple three dimensional shots. Multiple shots are usually required to destroy the target pathology. Step and shoot dose delivery involves repositioning the patient outside of the irradiation field to reposition the centroid of the conformal radiation dose. This type of radiosurgery has been time consuming and may in some cases have produced sub-optimal results. Radiosurgery may be performed using various devices. For example, Leksell (Elektra, Stockholm, Sweden) provides a Gamma Knife™ which may be referred to as an LGK. The LGK provides accurate stereotactic radio surgical brain lesion treatment. The LGK derives its therapeutic radiation from 201 60Co radiation sources. A patient is exposed to these sources through pluggable collimator channels. The radiation beams passing through unplugged collimator channels focus in the center of a collimator helmet to create an elliptically shaped conformal dose distribution. LGK shots are traditionally elliptical due to the general shape of the human skull. For a single shot, dose drop-off is steep at the boundaries of this ellipse (e.g., 90% to 20% isodose). However, dose drop-off steepness is diminished and made difficult to estimate when two or more shots have overlapping dose distributions. Shot planning seeks to achieve desired lesion coverage and killing. However, shot packing is not as simple as filling a tumor, a theoretical bag, with ellipses of dose. Planning multiple shots is difficult due to the consequences of unintended intersections of beams from different shots. These unintended intersections of beams from different shots complicate treatment planning, and thus lengthen the time required to plan a multi-shot treatment. Furthermore, shot packing approaches typically cannot commence until the entire pre-planning images are acquired. Planning and delivery complexity are related to the geometric complexity and volumetric complexity of a target volume. For example, large lesion volume, complex lesion shape, and/or complicated geometric relationships between the lesion and critical structures complicate planning, and thus increase planning time and increase the likelihood that suboptimal results will occur. Conventional LGK treatment planning begins with a treatment planning team that includes, for example, a neurosurgeon, a radiation oncologist, and a radiation physicist. The treatment planning team may survey pre-radio surgical images (e.g., CT, MR) to locate the lesion in a series of adjacent 2D image slices. Drawing the boundary of the lesion is referred to as “segmentation”. Other objects of interest, (e.g., critical structures near the lesion), may also be segmented at this time. Segmentation is typically performed manually using a contour drawing tool. Shot packing strategies may not begin until the entire set of image slices is available. Conventional treatment planning falls into two categories: forward treatment planning, and inverse treatment planning, with forward treatment planning being the standard of care as of 2007. Treatment planning begins with known parameters including prescribed dose, lesion location, segmented tissue object contours, and so on. Forward planning includes a trial-and-error approach for choosing shot parameters including number of shots, shot positions, collimator sizes, shot weights, and so on. As shot parameters are selected the treatment planning team can calculate and evaluate the sum of the radiation dose distribution. The treatment team will then manually adjust setup parameters until an “acceptable” treatment plan is obtained. This is an extremely technical and manual process requiring the input of several highly skilled personnel. This approach is not deterministic. Given time limitations imposed by single session treatment a significant issue for forward treatment planning is the relative size of the search and solution space for acceptable treatment plans. For a small lesion with a simple shape, forward planning may perform adequately. The treatment planning team may place a shot in the center of the target volume and then gradually add extra shots to fill the under-dosed regions closer to the lesion surface. However, the treatment plan search space increases dramatically when a lesion has a large target volume, a complex target shape, and/or a complex geometric relationship between the target volume and nearby critical section (CS). In this situation, treatment planning may require hours to obtain an acceptable treatment plan. The shots resulting from this trial-and-error procedure may produce unintended radiation dose overlap, particularly when multiple shots are placed in close proximity. In one embodiment Tomosurgery involves slice based radiosurgery that includes moving a high-precision, controlled-shaped isocenter between scan points along a set of scanning lines in a portion of a target volume divided into sets of treatment planes. In one example, the scan points may be visited in a raster-scanning pattern controlled by a set of 2D plans. Scan points may also be visited slice by slice through a target volume as controlled by a 3D plan built from the set of 2D plans. The slice thickness may be optimized to smooth peak-to-peak transitions between slices. Shot weight can be adjusted by controlling parameters including, but not limited to, shot movement speed, shot movement location, the number of beams being used in the shot, the distance of the radiation source from the target volume, and the size of beams used in the shot. The number of beams and the size of the beams may be determined by controlling on-the-fly collimator changes (e.g., plug pattern, plug size), and/or by controlling a radiation source position. The location of the isocenter can be moved by controlling parameters including, but not limited to, the number of different beams being used, temporal delays between beams, delivery apparatus location and/or orientation, radiation source location, and/or orientation, and patient location and/or orientation. Tomosurgery seeks the precise and complete destruction of a chosen target without significant unintended and/or unanticipated concomitant damage to adjacent tissue. The radiation used in Tomosurgery is ionizing high-energy beams that provide sufficient energy to cause electrons to escape from the outer shell of atoms in the target structure. The ionizing high-energy beams may radiate from, for example, 60Co. Cell death or injury may result from DNA, cell membrane, and/or organellar damage. Tomosurgery planning may include a two stage optimization where 2D slices are solved and then a 3D assembly of 2D slices is solved. To solve slices, the planning systems and methods need to have slices. Thus, the 3D target volume is first identified and then partitioned into 2D slices. The 3D target volume may be identified from images including, for example, MR images, CT images, PET images, SPECT images, X-rays, and so on. The 3D target volume may then be logically “cut” into smaller pieces. In one example, the smaller pieces are “slices” that can be considered to be two dimensional surfaces over which a shot isocenter can be passed. The 2D surfaces may be treated as a set of scan points lying in the same plane. The 2D projection images may be used to determine the placement of raster lines that connect scan points and thus control desired dose distribution in the first-stage optimization. On these 2D projection images, tumor and CS regions may overlap. Therefore, in one example, a set of rules may be used to control placement of raster lines on a raster-scan plane. The rules may include placing parallel raster lines sequentially along the y direction, locating discrete scan points of each raster line only within the tumor region in the corresponding projection image, and not locating any discrete scan point within the projected CS region. Using these rules facilitates determining the coordinates (x, y, z) of the discrete scan points making up raster lines. In one example, the final treatment plan is made up of a series of scan points assigned with the optimized weight as controlled, for example, by the speed of the moving shot. While a “slice” is actually a three dimensional volume, it may be treated as a two dimensional surface formed of a set of scan points for planning and treatment purposes. In one example, multiple slice orientations may be considered to provide multiple options for solving the set of 2D problems. Additionally, in one example, combinations of orientations may be considered to provide even more options for solving the set of 2D problems. For example, a first portion of a target volume may be sliced in a first orientation while a second portion of a target volume may be sliced in a second orientation. Solving slices arranged in different orientations may be computationally expensive but may provide superior results for target volumes that have particularly complicated geometries and/or that interact with (e.g., wrap around) critical structure (CS) in geometrically complex ways. Tomosurgery may involve both parallel planning and parallel delivery. Individual slices may be solved in parallel and may be solved according to different strategies simultaneously. For example, solutions that apply different importance functions and different scanning patterns may be solved simultaneously so that different options are available to attempt to solve the final 3D assembly. Additionally, different solutions that involve delivering a dose as a disk, an ellipse, or as another shaped shot may also be computed in parallel to make even further options available for the final 3D assembly. Additionally, different solutions that involve controlling dose (in)homogeneity may be solved in parallel to provide even further options for the final 3D assembly. Finally, multiple 3D assemblies may be computed in parallel and an optimal solution can be selected from the available plans. Different plans may be more deliverable using different delivery devices. Thus, part of the final 3D planning solution may include selecting a delivery device for the plan. For example, a first 3D plan may be optimized using a first delivery device (e.g., LGK) while a second 3D plan may be optimized using a second delivery device (e.g., medical LINAC). Reduction to 2D slices and parallel delivery may be possible since delivery apparatus (e.g., LGK) may be adaptable to provide a substantially continuous dose using substantially coplanar beams and/or sets of substantially coplanar beams. Using substantially coplanar beams may facilitate reducing unintended beam intersections which may in turn facilitate both simplifying planning and delivering therapy in parallel. Example systems and methods may perform intensity modulated radiation therapy (IMRT) by modulating the speed of a moving shot or moving shots. Dose can be controlled by how long a shot lingers in a certain location. In one example, the moving shot(s) may be disk-shaped, though other shot shapes may be employed. IMRT may rely on achieving relative motion between a patient and a radiation field to provide a planned radiation dose in a continuous fashion. The relative motion may be achieved by moving the patient, by moving the delivery apparatus, by moving the radiation source, and by combinations thereof. While some example systems and methods are described in association with an LGK, the systems and methods are not so limited. For example, treatment planning and radio-surgery may be associated with other delivery mechanisms and radiation sources including, for example, a cyberknife having a single point source of radiation, a C arm linear accelerator, an apparatus having multi-leaf collimators (MLC), and so on. Similarly, while example systems and methods are described in connection with brain surgery, the systems and methods are not so limited. For example, treatment planning and radiosurgery may be applied to other body parts including, for example, the torso, extremities, and so on. Additionally, while the examples are described in terms of human treatment, radiosurgery may be performed on additional subjects (e.g., dogs, horses, cows). Additionally, while example systems and methods describe a raster based approached associated with a moving shot, it is to be appreciated that other motion patterns may be employed. Raster based approaches may simplify mechanical adaptations to conventional apparatus and may facilitate simplifying motion plan computations. However, in some examples, other motion plans (e.g., helical, spiral) for the moving shot may be employed. In one embodiment, an LGK shot delivery mechanism dynamically moves a shot isocenter to control dose homogeneity and/or dose inhomogeneity. In one embodiment, an LGK plug-pattern that facilitates selectively blocking collimators on an LGK helmet is used. For example, all the collimators except those on a single layer (e.g., lowest layer, most nearly coplanar row) are blocked. This facilitates producing substantially coplanar beams. Thus, a focused isocenter dose profile can be produced within a narrow plane. The patient and/or field can be moved to make the plane correspond to one of the 2D planes for which a raster plan has been computed. The “shot” created by this plug-pattern may be a disk-shaped distribution of lethal radiation (e.g., a shot). References to “one embodiment”, “an embodiment”, “one example”, “an example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in one embodiment” does not necessarily refer to the same embodiment, though it may. The following includes definitions of selected terms employed herein. The definitions include various examples and/or forms of components that fall within the scope of a term and that may be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of terms may be within the definitions. “Machine-readable medium”, as used herein, refers to a medium that participates in directly or indirectly providing signals, instructions and/or data that can be read by a machine (e.g., computer). A machine-readable medium may take forms, including, but not limited to, non-volatile media (e.g., optical disk, magnetic disk), and volatile media (e.g., semiconductor memory, dynamic memory). Common forms of machine-readable mediums include floppy disks, hard disks, magnetic tapes, RAM (Random Access Memory), ROM (Read Only Memory), CD-ROM (Compact Disk ROM), and so on. “Data store”, as used herein, refers to a physical and/or logical entity that can store data. A data store may be, for example, a database, a table, a file, a list, a queue, a heap, a memory, a register, a disk, and so on. In different examples a data store may reside in one logical and/or physical entity and/or may be distributed between multiple logical and/or physical entities. “Logic”, as used herein, includes but is not limited to hardware, firmware, executing instructions, and/or combinations thereof to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. Logic may include a software controlled microprocessor, discrete logic (e.g., application specific integrated circuit (ASIC)), an analog circuit, a digital circuit, a programmed logic device, a memory device containing instructions, and so on. Logic may include a gate(s), a combinations of gates, other circuit components, and so on. Where multiple logical logics are described, it may be possible in some examples to incorporate the multiple logical logics into one physical logic. Similarly, where a single logical logic is described, it may be possible in some examples to distribute that single logical logic between multiple physical logics. An “operable connection”, or a connection by which entities are “operably connected”, is one in which signals, physical communications, and/or logical communications may be sent and/or received. An operable connection may include a physical interface, an electrical interface, and/or a data interface. An operable connection may include differing combinations of interfaces and/or connections sufficient to allow operable control. For example, two entities can be operably connected to communicate signals to each other directly or through one or more intermediate entities (e.g., processor, operating system, logic, software). Logical and/or physical communication channels can be used to create an operable connection. “Signal”, as used herein, includes but is not limited to, electrical signals, optical signals, analog signals, digital signals, data, computer instructions, processor instructions, messages, a bit, a bit stream, or other means that can be received, transmitted and/or detected. “Software”, as used herein, includes but is not limited to, one or more executing computer instructions that temporarily transform a general purpose machine into a special purpose machine. Software causes a computer, processor, or other electronic device to perform functions, actions and/or behave in a desired manner. Software may be embodied in various forms including routines, algorithms, modules, methods, threads, and/or programs. In different examples, software may be implemented in executable and/or loadable forms including, but not limited to, a stand-alone program, an object, a function (local and/or remote), a servelet, an applet, instructions stored in a memory, part of an operating system, and so on. In different examples, computer-readable and/or executable instructions may be located in one logic and/or distributed between multiple communicating, co-operating, and/or parallel processing logics and thus may be loaded and/or executed in serial, parallel, massively parallel and other manners. “User”, as used herein, includes but is not limited to, one or more persons, software, computers or other devices, or combinations of these. Some portions of the detailed descriptions that follow are presented in terms of algorithm descriptions and representations of operations on electrical and/or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in hardware. These are used by those skilled in the art to convey the substance of their work to others. An algorithm is here, and generally, conceived to be a sequence of operations that produce a result. The operations may include physical manipulations of physical quantities. The manipulations may produce a transitory physical change like that in an electromagnetic transmission signal. It has proven convenient at times, principally for reasons of common usage, to refer to these electrical and/or magnetic signals as bits, values, elements, symbols, characters, terms, numbers, and so on. These and similar terms are associated with appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, it is appreciated that throughout the description, terms including processing, computing, calculating, determining, displaying, automatically performing an action, and so on, refer to actions and processes of a computer system, logic, processor, or similar electronic device that manipulates and transforms data represented as physical (electric, electronic, magnetic) quantities. FIG. 1 illustrates a portion 100 of three dimensional target volume that has been logically partitioned into a set of two dimensional treatment slices. In one embodiment, Tomosurgery involves continuously delivering a radiation dose with dynamic intensity modulation performed temporarily, spatially, or both in accordance with a 3D plan derived from a set of 2D plans developed for the set of treatment slices. The radiation may be delivered to a set of scan points arranged along a set of scan lines (e.g., 191, 192, . . . 199) that correspond to treatment lines 110, 111, . . . 119 in portion 100. The spatial intensity modulation may be achieved by moving the center of a shot, which may be achieved by causing relative motion between a patient, a delivery apparatus, and/or a radiation source. In one embodiment, a continuous LGK shot delivery mechanism may dynamically move a shot isocenter to control dose homogeneity. The LGK may be configured to deliver dose continuously with a modulated shot radiation dose level moving at modifiable speeds along suitable pathways in accordance with the set of 2D plans to improve both dose conformality and normal tissue sparing. The 2D plans may be solved independently and in parallel to reduce planning time. The 2D planning problems may include varied-speed shot movement to improve dose conformality. The 2D plans may then be assembled into a 3D plan. Once again, segments of the 3D plan can be assembled in parallel. Consider a 3D volume sliced into 256 2D slices for planning. In one example, some or all of the 256 2D slices may be solved in parallel. Additionally, some or all of the 256 2D slices may be solved using different parameters (e.g., importance functions, scan plans). Plans for the 256 2D slices may then be assembled into a 3D plan. Once again, multiple 3D plans may be computed in parallel and a most optimal solution chosen at the end. In one example, 16 separate process may be tasked with assembling sets of 16 slices in parallel. In another example, 128 process may assemble sets of adjacent slices, then 64 processes may assemble sets of four slice assemblies, and so on. Larger subsets of slices may then ultimately be assembled into the final 3D model. With one 3D plan made up of multiple 2D slices, in one example radiation may be delivered to treat different slices in parallel. Parallel radiation delivery within isolated treatment slices facilitates reducing therapy delivery time. Improvements in dose conformality and homogeneity may also improve radiosurgery for larger-volume and/or more geometrically complex lesions. Example systems and methods may control a delivery apparatus to produce a disk-like shot using a delivery apparatus that produces a nearly planar dose. These systems and methods may rely on a kinetic equation that describes a “3D dose bar” radiation distribution when this disk-like shot moves through a lesion in each treatment slice in, for example, a raster scanning fashion. Example systems and methods may consider the characteristics of the 3D dose bar, consider the interaction between adjacent 3D dose bars in the same slice (e.g., inter-raster line dose), and consider the interaction between two slices (e.g., inter-slice dose). Example systems and methods may also consider dose interaction and inhomogeneity resulting from changing dose bar velocity. Example systems and methods may use information concerning disk-like shot radiation dose distribution to automatically generate an inverse treatment plan that includes modulated velocity. In one example, Tomosurgery inverse treatment planning involves a two-stage optimization strategy utilizing an importance-weighted quadratic objective function and iterative least-square minimization. The resulting delivery causes a shot to move continuously through a target volume (e.g., lesion) delivering tumoricidal radiation to a series of adjacent slices in a raster-scan format. So long as relative motion between the target volume and the irradiation field is possible, continuous motion of the radiation dose is possible. The inverse treatment planning is to be performed in a clinically relevant and acceptable time frame to provide improved plan quality and application to different radiation therapy modalities. Moving the high-precision shaped isocenter relies on being able to produce relative motion between a target volume and an irradiation field. The relative motion may be achieved using positioning units associated with the patient, the delivery apparatus, the radiation source, and so on. For example, equipping an LGK with two positioning units, each of which has three computer controlled motors, may facilitate continuously changing the position of the shot isocenter. As described above, pre-operative 3D MR-scanning, LGK treatment planning, and LGK radiosurgery may need to be accomplished in a single work session. Thus, time is of the essence. The single session is conventionally mandated because the rigid stereotactic frame is affixed to a patient's skull. This fixed length of time may lead to compromises between manual treatment planning and the radiosurgery procedure in complex cases. While conventional systems tend to wait until the entire 3D MR-scan is complete, some example systems can start solving some individual 2D slices as soon as they are available, further reducing overall planning and thus session time. In some cases, 3D pre-operative imaging, tomosurgery planning, and radiation delivery may be separated into different sessions that do not need to be completed in a single session by the use of fiducials that may be affixed to the target volume and/or to anatomy that will maintain a constant relationship to the target volume in between imaging, planning, and delivery. For example, a set of three fiducials that are highly visible to MR imaging may be affixed to a patient skull in a pre-determined pattern and used subsequently in planning and/or delivery. For a treatment slice, the central transverse plane may be referred to as the “raster-scan plane” in which the disk-shaped shot moves in a raster format. The treatment slices may have an optimal slice thickness. In one example, the slice-scan nature of the Tomosurgery paradigm is understood by analyzing dose distribution for a constant-speed moving disk-shaped shot in the form of linear scan, single-plane raster scan and multi-plane raster scan. Analyzing dose distribution by linear scan (moving shot along a straight line) facilitates obtaining the optimal slice thickness. Analyzing single-plane and multi-plane raster scans facilitates understanding dose distribution, including approximated dose drop-off steepness and isodose contour width. The following discussion illustrates the analysis. In one example, a disk-shaped shot is generated using a helmet plug-pattern having the upper four layers of a commercially available collimator closed with only a fifth layer open. This approximates coplanar beams. In the example, the voxel size of the 161×161×161 3D matrix that stores the dose kernel is 0.25×0.25×0.25 mm3. Different dose kernels for available collimator sizes (e.g., 4 mm, 8 mm, 14 mm, 18 mm) may be calculated. In one example, a 4 mm collimator is used since smaller shots increase the likelihood of achieving greater dose conformality. Given a disk-shaped dose kernel matrix d and a moving speed related variable v(x) at the location x, a dose distribution D due to a linear scan along the x axis can be expressed according to: D ⁡ ( x , y , z ) = d ⊗ 1 v = ∑ x ′ ⁢ d ⁡ ( x - x ′ , x , y , z ) ⁢ ( 1 / v ⁡ ( x ′ ) ) ( 1 ) where {circle around (x)} is the convolution operator. For disk movement performed with discrete steps, v(x) is a shot-weight series. In one example, the speed may be treated as a constant and the 60Co can be assumed not to decay. In this example, equation (1) simplifies to: D ⁡ ( x , y , z ) = ∑ x ′ ⁢ d ⁡ ( x - x ′ , y , z ) ( 2 ) If the straight line along which the disk-shaped shot moves is considered to be infinitely long, then the example can ignore the regions close to the start and end points. Therefore, D can be treated as a bar-shaped compressed cylinder and the dose profile on a cross-sectional plane (y-z) of the 3D dose bar will be the same, (e.g., D(x1, y, z)=D(x2, y, z) for arbitrary x1 and x2). Therefore, the cross-sectional dose profile of the 3D dose bar can be denoted as Dcs(y, z) for purposes of simplification. Given Dcs(y, z) as the cross-sectional dose profile of the 3D dose bar, define Dcs(y=0, z) as the function φ, which is approximately symmetrical by z=0. In one embodiment, planning may depend on previously determining the similarity between φ and Dcs(y, z) at arbitrary y fixed and determining the optimal offset for two shifted φ functions so that their summation has the flattest/smoothest peak-to-peak transition. For the sum of two shifted bell-shaped functions, such as F(x)+F(x+offset), the peak-to-peak transition represents the curve between the peaks of F(x) and F(x+offset). Because the correlation coefficient is independent of origin and scale, it may be used to evaluate the similarity of Dcs(y, z) to φ at different fixed y. The correlation coefficient has the value between 0 and 1. The complete correlation has the correlation coefficient equal 1. The pre-determining may include searching for an optimal offset for which the sum of two shifted φ functions has the smoothest peak-to-peak transition. Given two shifted φ functions, φ(z) and φ(z−lo), define Hlo(z) as:Hlo(z)=c·Φ(z)+Φ(z−lo), cε[0.5, 1] (3) where c is a constant and lo is the offset between those two shifted φ functions. When c equals 1, a horizontal line from peak to peak (z ε [0, lo]) is desired to present the most smoothness. When c is less than 1, a non-horizontal straight line is expected to ideally reach the most smoothness. To quantify the smoothness, define the smoothness as the average of the unsigned curvature of the given curve segment (peak-to-peak transition). The unsigned curvature κ in this case can be given as: κ ⁡ ( z ) =  ∂ H l o ⁡ ( z ) ∂ 2 ⁢ z ( 1 + ( ∂ H l o ⁡ ( z ) ∂ z ) 2 ) 3 / 2  ( 4 ) The predetermining may also include calculating κ in discrete form. By focusing on peak-to-peak smoothness for a particular region (e.g., the curve segment of Hlo(z) when 0≦z≦lo), the peak-to-peak smoothness Cs(lo) can be presented as the arithmetic mean of the curvature in discrete: C s ⁡ ( l o ) = 1 N ⁢ ∑ i = 1 N ⁢ κ i ( 5 ) where the peak-to-peak curve segment of Hlo(z) is represented by N discrete points. Because the curvature measures the failure of a curve to be a straight line and the curvature of a regular straight vanishes if that straight line is not horizontal, the smoothest peak to peak transition will be obtained when Cs(lo) tends to zero. The predetermining may also include analyzing 3D dose bars derived from clinical cases. The analysis may include searching the optimal offset lo where Cs(lo) is minimum for different c value in Hlo(z), such as c=0.5, 0.6, 0.7, 0.8, 0.9, and 1. The shot dose kernel matrix used has the voxel size at 0.25×0.25×0.25 mm3. In one example system, the planar raster scan may be performed on a transverse plane (x-y). A single-plane raster scan may be made up of multiple parallel linear scans on the same plane. A multi-plane raster scan can be formed from a stack of single-plane raster scans. While a single-plane raster scan is described, it is to be appreciated that other scanning patterns may be employed (e.g., spiral, helical). The cross-sectional dose profile Dcs(y, z) of a single 3D dose bar is approximately mirror-symmetrical along either z or y axis. The minimal and mean correlation coefficient is no less than 0.977 and 0.991 respectively. Therefore, Dcs(y, z) has substantially the same function form as φ at any y value, but different scale. Thus, Dcs(y, z) can be expressed at arbitrary y as:Dcs(y,z)=Dcs(y,0)·Φ(z), at arbitrary y (6) The single-plane raster scan can be regarded as the alignment of multiple parallel 3D dose bars centered by the same plane in a raster format where each raster line is the axial of the respective 3D dose bar. Dose distribution delivered by a single-plane raster scan can be approximated as a sum of multiple φ functions with varied scale along any longitudinal line (parallel with z axis) in dose space regardless of inter-raster line distance. Assume the single-plane raster scan has N raster lines and the inter-raster line distance is la. The dose distribution for this single-plane raster scan on a cross-sectional plane can be presented as Dsps(y, z): D sps ⁡ ( y , z ) = ∑ n = 1 N ⁢ D cs ⁡ ( y + ( n - 1 ) · l a , z ) = ∑ n = 1 N ⁢ D cs ⁡ ( y + ( n - 1 ) · l a , 0 ) · Φ ⁡ ( z ) = Φ ⁡ ( z ) ⁢ ∑ n = 1 N ⁢ D cs ⁡ ( y + ( n - 1 ) · l a , 0 ) ( 7 ) Note that Dcs(y+(n−1)·la,0) is a constant. Therefore, for the single-plane raster scan the dose profile along a longitudinal line Dsps(y,z) at arbitrary y fixed, will reserve the function form of φ but has varied scale determined by: ∑ n = 1 N ⁢ D cs ⁡ ( y + ( n - 1 ) · l a , 0 ) . In one example, an optimal offset for φ may exist. In the provisional application, this optimal offset was seen at 4.01 mm. Even while c in the Hlo function was not 1, the optimal offset was still 4.01 mm. Thus, the optimal offset value may be universally valid so that the smoothest dose transition by the multi-plane raster scan along any longitudinal line can be reached if the treatment slice thickness equals the optimal offset. Therefore, by choosing the treatment slice thickness to be the same as the optimal offset, a multi-plane raster scan in the raster format by a disk-shaped shot will generate smooth dose transition around treatment slice junctions instead of unexpected dose overlapping due to hard-to-predict beam intersections/overlapping, and divide the lesion into the least number of treatment slices without sacrificing dose homogeneity inside the lesion. In the experiments described in the provisional application, the FWHM values (4.01 mm) were close to the optimal offset values for all cases and therefore may be used to approximate the optimal treatment slice thickness directly. Hlo may be defined as a weighted sum of two shifted φ functions corresponding to the scenario with the two raster lines per single-plane raster scan instead of multiple shifted φ functions associated with the more general cases with several raster lines per single-plane raster scan. For multiple shifted φ functions with the same optimal offset value the overlapped dose will still have the smooth/flat transition from peak to peak since φ has the very steep drop-off so that one φ function has minimal impact on another φ function that is far enough away. A lesion volume might not be exactly divided by the optimal treatment slice thickness, leaving a portion of a lesion undivided. When the offset value lo increases outside a pre-defined range, the profile of Hlo between the peaks of two overlapped φ functions varies from a hill to a platform and then to a valley. If the optimal offset value cannot be used, then a smaller Hlo is favored because a larger Hlo may lead to under-dosed peak-to-peak transition. Example systems and methods may use single-plane raster scanning to create elliptical isodose contours on cross-sectional planes. Example systems and methods may then extend to multi-plane raster scanning by stacking multiple single-plane raster scans. Example systems and methods may rely on the dose overlapping effect in situations where one treatment slice is smaller than another. This facilitates creating a dose conformal to the lesion volume if the cut-off cross-sectional geometrical shape of a lesion has continuous and roughly 1st order linear change within a pre-defined thickness. Therefore, example systems and methods may consider the dose distribution on the mid-plane of a treatment slice, which can be planned as a 2D problem. After assembling (e.g., stacking) individually planned treatment slices, the overlapped dose from slice to slice will conform to the lesion geometric changes from one treatment slice to another. Therefore, the original 3D planning problem is converted to a series of 2D planning problems that can be individually solved without 3D, convolution, which means planning time can be reduced. Planning time can be reduced even further because the individual 2D planning problems may be solved in parallel and planning may begin even before the entire 3D MR image is acquired. 2D solutions may then be stacked into the 3D plan, with the stacking occurring in parallel. In some examples, different approaches to solving the individual 2D planning problems may be undertaken in parallel with optimal solutions being selected from the results of the different approaches. Similarly, different approaches to solving the 3D assembly problem may be undertaken in parallel with an optimal solution being selected from the different solutions. Example systems and methods may consider how isodose contours vary while applying different scan formats. The number of single-plane raster scans affects the width of isodose contours along the longitudinal z direction only. Thus, stacking multiple single-plane raster scans having an optimal treatment slice thickness does not worsen the dose spread-out within each treatment slice itself and will proportionally expand isodose contours/surfaces along longitudinal z direction. Therefore, single-plane raster scanning can be seen as individually filling a dose within a corresponding treatment slice. In example systems and methods, modulating shot speed facilitates improving conformality of the dose to the target lesion. In example systems and methods, a Tomosurgery treatment plan includes a series of raster lines that include a series of discrete scan spots/stops where the moving shot will stay. A time-factor is assigned to a scan spot and represents how long the moving shot takes passing through. Assuming an undecayed radiation source, this time-factor is analogous to shot weight. In one example, Tomosurgery treatment planning first determines the location of a series of adjacent treatment slices that cover the entire lesion volume. Second, the 3D volumes for tissue types (e.g., lesion, CS, normal tissue (NT)) within each treatment slice are projected to the central transverse plane of that treatment slice. In one example, the disk-shaped Tomosurgery shot dose profile at ≧50% isodose is approximately the same thickness as each treatment slice and therefore the treatment plan can be solved for a 2D projection view of each treatment slice. Thus, 2D plan optimizations involve 2D convolution, which can be performed more quickly than 3D convolution. Third, the 3D dose distribution of optimized 2D plans are calculated. These 3D dose distributions are assembled (e.g., stacked) longitudinally to create the final 3D plan. Example systems and methods may consider how to orient treatment slices. It is computationally simplest if the treatment slices are parallel to the original MR-based x-y plane. In this case treatment slice thickness can be measured along the longitudinal z axis. The lesion thickness may, or more likely may not be fully divisible by the optimal treatment slice thickness. A 2D plan may manage a single-plane raster scan by the moving disk-shaped shot. Dose level in each treatment slice may increase slightly after the 3D treatment plan is directly assembled. A target volume (e.g., lesion) may not be exactly divisible into slices of the optimal thickness. Thus, there may be a remaining undivided portion of target volume thickness. Therefore, example systems and methods may organize an additional treatment slice that covers the undivided lesion portion that is partially overlapping with the first or the last slice previously divided out. For these two partially overlapped slices, assembling the corresponding 2D plans will not yield a smooth/flat peak to peak transition. In some examples, treatment slices may have a transverse (x-y) orientation, the same orientation as an original MR slice data. Other example systems and methods are not so limited. In one example, a target volume may be serially sectioned into treatment slices along the pre-determined longitudinal z direction. The central transverse plane of a treatment slice is referred to as “raster-scan plane” onto which the disk-shaped moving shot may be aligned. Given an overall tumor volume thickness T along the longitudinal direction (e.g., the z direction) and an optimal treatment slice thickness Topt, the division of the tumor volume can be determined, in one example, using the following expression:T=Topt×N+R (3-1) There are two possible situations: 1) R=0, where T can be exactly divided by Topt and 2) R≠0, where T cannot be exactly divided by Topt and the remaining undivided portion of the tumor volume has a thickness<Topt. For both of these situations, the corresponding central transverse planes of the initial N treatment slices may be chosen as the raster-scan planes so that the distance between two adjacent raster-scan planes is Topt. If the tumor volume is completely filled by these treatment slices (R=0), the procedure can conclude. If the tumor volume can not be filled completely (R≠0), an extra raster-scan plane (N+1th) may be appended. However, the distance between the last two raster-scan planes (Nth and N+1th) is R instead of Topt. In an example described in the provisional application, Topt is 4 mm for the use of a 4 mm collimator. It is to be appreciated that for other collimator sizes other optimal slice thicknesses may be employed. For the raster-scan planes, a serial raster line may be used as the path for the moving disk-shaped dose. In one example, zs, the position of a raster-scan plane is recorded along the z direction. The volumes of different tissue types within the range of zs±X mm may be projected onto the corresponding raster-scan plane. These 2D tissue projections are used to determine the desired dose distribution in the first-stage optimization. The 2D projections of both the tumor and CS may be saved separately while the regions without tumors or CS may be regarded as NT. Overlap of the 2D tissue projections for tumors and CS is possible in some situations. Given the 2D tissue projection for a raster-scan plane, the rules described above can be applied to place the raster lines. The rules facilitate determining the coordinates (x, y, z) of these scan points making up the raster lines. Using a disk-shaped dose kernel and a set of scan points representing the raster lines, the resulting dose can be calculated using: D d = d * τ ⇒ D d ⁡ ( x , y ) = ∑ m ⁢ ∑ n ⁢ d ⁡ ( m - x , n - y ) ⁢ τ ⁡ ( m , n ) ( 3 ⁢ - ⁢ 2 ) where τ represents a time series variable that represents the time it takes the “moving shot” to pass through a “unit length” of each raster line. More specifically, τ is the shot weight in the terminology of the conventional LGK, and, finally, d is the disk-shaped shot dose kernel. In one example, both optimization stages may use a similar quadratic objective function and importance-weighted iterative least-square minimization. Adjustment of the prescribed dose or the importance factors can push a treatment plan via this optimization towards a desired result. In one example, the prescribed dose for each case may be adjusted to control the average dose in the entire tumor volume. The importance ratio may be emphasized to match planned dose distribution to desired dose distribution for one (e.g., tumor only) or two (e.g., tumor plus CS) tissue types. An importance-weighted objective function may be used to solve for τ: O ⁡ ( τ _ ) = ∑ tissue ⁢ ∑ i ⁢ I i ⁡ ( D i P - D i d ) 2 = ∑ tissue ⁢ ∑ i ⁢ I i ( D i P - ∑ j ⁢ d ij ⁢ τ j ) 2 ( 3 ⁢ - ⁢ 3 ) where Dip is the prescribed dose for the tumor, NT, and CS, Did is the planned dose distribution to be optimized, dji of the dose kernel represents the dose contribution to the ith spatial location while the shot moves through the jth scan point. Because the slice information may be projected to the corresponding raster-scan plane, the dose calculation at this stage is a 2D convolution operation that uses the central transverse plane of dji. li is the predefined importance factor of each tissue type assigned to the ith spatial location. The projection results in tumor and CS may overlap and thus there may be a location on a 2D projection where both a tumor and a CS appear. Therefore, one example may treat the cost of Eq. (3-3) as the sum of the contributions from all three tissue types. Eq. (3-3) is a convex problem that may be solved using an iterative least-square minimization based on the following iterative equation: τ j k + 1 = τ j k ⁡ ( ∑ tissue ⁢ ∑ i ⁢ I i · d ji · D i P ) · ( ∑ tissue ⁢ ∑ i ⁢ I i · d ji ⁢ D i d ( k ) ) - 1 ( 3 ⁢ - ⁢ 4 ) The solution space search is guided by an “update” factor that is the ratio between the prescribed dose and the calculated dose from the previous iteration. In one example, it may be possible to fix the normalized prescription dose to 0.8 for tumor, 0.2 for NT, and 0.2 for CS. Given n 2D treatment plans produced by the first-stage optimization, the assembly of the final 3D plan dose distribution (Df) is performed by weighting these n 2D plans according to: D f = ∑ n ⁢ w i · D i s ( 3 ⁢ - ⁢ 5 ) where Dis is the 3D dose matrix saving the dose distribution by the ith single-plane raster scan (e.g., the 2D treatment plan), and is calculated based on Eq. (3-2); wi is the weight assigned to the ith single-plane raster scan and the variable to be solved by the second-stage optimization. If wi=1, there is no adjustment to the ith planar scan. A large change of wi from 1 means that there is a large adjustment. The dose distribution for a single-plane raster scan has steep dose drop-off along the longitudinal z direction. Therefore, one example may limit the thickness of the dose matrix Dis to 3×Topt, to save computation time. An importance-weighted objective function similar to Eq. (3-3) and an iterative equation similar to Eq. (3-4), derive the second stage optimization presented in Eqs. (3-6) and (3-7), respectively: O ⁡ ( w _ ) = ∑ tissue ⁢ ∑ I · ( D f P - D f d ) 2 = ∑ tissue ⁢ ∑ I · ( D f P - ∑ N + 1 ⁢ w i ⁢ D i s ) 2 ( ⁢ 3 ⁢ - ⁢ 6 ⁢ ) w i k + 1 = w i k ( ∑ tissue ⁢ ∑ N + 1 ⁢ I · D i s · D f P ) · ( ∑ tissue ⁢ ∑ N + 1 ⁢ I · D i s ⁢ D f d ( k ) ) - 1 ( ⁢ 3 ⁢ - ⁢ 7 ⁢ ) where l is the importance factor assigned to each tissue type; w is a vector of size n, the number of the 2D treatment plans. In this second-stage optimization, one example may fix the normalized tolerance dose at 0.2 for NT, and adjust the prescription dose for tumor tissue virtually by a trial-and-error approach that depends on both tumor volume and whether CS is present. Adjustment away from the prescribed tumor dose may occur as a trade-off between in-tumor average dose and dose conformality. A highly conformal dose in a small tumor may be closer to the original prescribed dose (e.g., relatively higher) than in a large tumor. In one example, the importance ratios of tumor:NT:CS may be set the same in the second-stage optimization as in the first-stage. After the second-stage optimization, the time-series τ of each 2D treatment plan may be adjusted by multiplying the corresponding weight wi in order to get the final, optimized, 3D LGK Tomosurgery treatment plan. In one example, the first-stage optimization of each 2D slice treatment plan can be limited to a pre-determined, configurable number of iterations (e.g., 50). In one example, second stage weight adjustments may be made. A large weight adjustment may occur on the last two 2D treatment plans because of the partial overlap of the last two treatment slices, and a small weight adjustment may occur on the treatment slices nearest the tumor central transverse plane. To get the final 3D plan, τ of each 2D treatment plan may be multiplied by the corresponding weight wi. In one example, second-stage optimization may be limited to a pre-determined, configurable number of iterations (e.g., 5). A smaller number of iterations may be employed since complex 3D convolution calculations may be reduced. This also provides treatment planning time improvements over conventional methods. After first-stage optimization, the time-series τ is extended (e.g., the shot lingers) near the tumor boundary and smoothly decreases its value (e.g., increases the speed) as the disk-shaped shot progresses toward to the tumor center. Also, the optimal value of τ tends to be less variable in this central area. The optimization algorithm seeks to match the planned dose distribution to this desired flat dose distribution. Near the tumor boundary, the reduction in adjacent raster lines results in reduced, dose contributions. As a result, raster lines near the tumor boundary optimally have a boosted dose that compensates for the reduction in adjacent scan lines. In the center of the tumor, raster lines have a similar number of nearby scan lines. Thus τ is approximately constant to create the desired constant dose distribution by the optimization. Each optimized single-plane raster scan by the corresponding 2D plan has the desired flat “dose pie” enclosed by the 50% prescription isodose surface. The second-stage optimization may adjust 2D treatment plans during the 3D plan assembly. The last two slices (e.g., end slice and next to end slice) often have the scanning planes closer to each other than the other adjacent slices and thus the dose transition between them has a higher amplitude with a hill profile. Dose weighting adjustments are determined by factors like the total length of each raster line in the current treatment slice and in the nearby treatment slices, the longitudinal position of each raster-scan plane, and the number of all raster-scan planes. The tumor prescription dose may be changed in the second-stage optimization so that the average in-tumor dose is not too high. Making modest changes in the prescribed dose during the optimization facilitates improving dose homogeneity and/or conformality. Dose conformality and CS survival may be closely coupled since they may be mutually exclusive goals. Tomosurgery may employ various delivery apparatus that produce high-accuracy focal radiation dose delivery in the form of a moving, disk-shaped isocenter that results from the intersection of multiple beamlets. The apparatus may employ a rigid yet mobile frame-based patient localization device supporting dynamic dose delivery via a moving isocenter. In one example, an existing LGK may be modified. One example platform includes a medical Linac™ (Varian Associates, Palo Alto, Calif.) mounted with a multi-leaf collimator (MLC). The Peacock™ system (NOMOS Corporation, Sewickley, Pa.) is one commercially available, MLC-mounted system. The Linac can shape radiation to a slit (fan) beam. The platform may include an optional ring-shaped secondary helmet with multiple collimator channels through which multiple beams can focus to an isocenter mimicking an LGK Tomosurgery disk-shaped shot, and a high-accuracy robotic positioning system that connects a head frame to the ring-shaped secondary helmet. In one example, a delivery apparatus could include a secondary helmet that includes a solid bowl or cylindrical tube with a ring-shaped base. This secondary helmet may be placed on a high-precision computer-controlled rotary table, so that it can rotate with an expected, controllable angular velocity. The base of the rotary secondary helmet may have multiple collimator channels that shape radiation beams received from an externally slit beam into multiple temporally delayed small beamlets. These beamlets, which may be temporally delayed due to the rotation of the helmet, focus to create a disk-shaped isocenter dose. A stereotactic (head) frame may be attached to this helmet through an automatic phantom positioning system similar to the APS of the LGK model C. Example systems and methods may interact with a calibration unit. In a polymer gel-MRI dosimeter, a polymer gel may be formulated by dispersing monomer into an aqueous gel matrix. Irradiated polymer gel will present a different T2 relaxation rate than non-irradiated polymer. Therefore, following irradiation, a T2-weighted 3D MR image of the gel-based phantom may be used to report the absorbed dose distribution. For a specific gel formulation, the relationship between absorbed dose distribution and R2 (1/T2) weighted map may be assumed to be linear within a suitable range. Compared with other radiosurgery/radiotherapy dosimeters, the polymer gel-MRI method provides high resolution 3D dose distribution data. Once a polymer gel-MRI dosimeter has been calibrated, it can be used to verify the dose delivery accuracy of a Tomosurgery procedure. To increase the co-registration accuracy of the treatment plan and the dosimeter 3D MR image of the delivered dose, multi-modality fiducial markers may be employed. PABIG (polyethylene glycol diacrylate, N,N′-methylenebisacrylamide, gelatin) gel formulation may be used with the dosimeter. An MR-scan of the irradiated gel-based phantom may use a volume selective 32-echo Carr-Purcell-Meiboom-Gill pulse sequence (e.g., TE1, TE2, . . . , TE32=40 ms, 80 ms, . . . , 1280 ms, TR of 2.3 s, reconstructed voxel size of 1×1×1 mm3) with phase encoding being applied in two orthogonal directions and Fourier interpolation taking place in the slice reconstruction direction. The readout T2 matrix includes the reconstructed slices converted to an R2 (1/T2) matrix. The calibration curve of the PABIG gel preparation is obtained by linearly fitting R2 values in the dose range of 0-35 Gy through the following equation:R2(D)=αD+R2(0) (5-1) where α is the dose sensitivity value and D is the dose level. Then, the calibration curve is normalized. The dose delivered to the phantom may be obtained using the same MRI pulse sequence. Dosimetry may include acquiring two images, a pre-operative (e.g., pre-irradiation) and a post-operative (e.g., post-irradiation) MRI scan of the phantom. The pre-operative MRI scan may be performed by using a spoiled T1-weighted 3D-fast field echo (FFE) sequence. The pre-operative MRI image may be input to the treatment planning algorithm which simulates the Tomosurgery procedure. The post-operative MRI scan may be based on the same MRI sequence used in the gel-MRI dosimeter calibration scan. The MRI readout may be converted to a R2 matrix and then converted to a normalized dose (percentage) based on the calibration curve. To deliver radiation to an isocenter with an accurate distribution and weight, an apparatus may include a portion that rotates continuously with a known, controllable, angular velocity. A fixed slit beam (20 cm×2 cm) may irradiate the rotating secondary ring collimator with the phantom attached internally. In one example, delivering x-y planar symmetrical radiation at each isocenter may be simplified by using a 360 degree rotation of the collimator helmet with a constant angular velocity. Given fixed Linac output power, and a constant angular velocity for the rotary collimator helmet, the dose rate detected at the isocenter may be deterministic. The radiation beams passing through the collimator channels of the secondary helmet may be analyzed and characterized using a gel-MRI dosimeter. Then, a dose kernel calculation model may be used to match the setup. Then, the relationship of the delivered isocenter dose rate to the angular velocity of the rotary helmet may be obtained. The knowledge of this relationship (ref. Eq. (5-2)) facilitates transferring the Tomosurgery treatment plan to other dose delivery plans. Based on the Tomosurgery treatment planning algorithm described above, a final treatment plan may be made up of a series of scan points assigned with the optimized weight (speed). Given fixed Linac output power, the shot moving speed (weight) may be converted to the corresponding angular velocity of the rotary helmet based on the simplified equation: ω i = 2 ⁢ ⁢ π D d / η ⁡ ( w i ) ( 5 ⁢ - ⁢ 2 ) where ωi represents the angular velocity of the rotary helmet to deliver the isocenter shot to the ith scan point; w is the weight (shot speed) assigned to a scan point; η is a function of w describing the dose rate converted from the shot speed; and, Dd is the desired dose to be delivered. For this simplified equation, factors and coefficients relevant to the radiation physics is implicitly modeled by the function η. The model η and the dose kernel calculation model may be specific to the radiation source and the secondary helmet design. To translate the Tomosurgery paradigm to the LGK, there are at least two options: 1) replacing the original manufacturer components with an automatic positioning system based on a pair of Cartesian robots; or 2) not only changing the positioning system, but also changing the secondary helmet and the placement of radiation sources. In one example, only the fifth-layer collimator channels (44 totally corresponding to 44 Cobalt-60 sources) are opened. Thus, the dose rate is lower than that of a plug pattern with all collimator channels (201 totally) opening. The dose rate could be increased if a customized secondary helmet was used. Thus, it may be possible to increase the number of or change the shape of collimator channels in a customized secondary helmet. The number of Cobalt-60 sources could also be increased. Note that the collimator orientation of the current secondary helmet does not allow beamlets to conform in a coplanar fashion. Therefore, in one example, in an LGK dedicated to Tomosurgery, the number of Cobalt-60 sources may be increased and the secondary collimator helmet may be modified to provide only coplanar radiation beams. Motorized control of a multi-leaf blocker (MLB) may be implemented using a series of parallel leaves that may be individually controlled. These leaves may slide in/out to turn on/off an underneath collimator channel on-the-fly during the treatment delivery, allowing for more flexible dose shaping (e.g., conformality). Thus, a computer-controlled MLB system may allow more complex treatment delivery including dose shaping and steeper dose drop-off, thereby significantly reducing the dose to which normal and critical structures would be exposed. An automated MLB may provide on-the-fly collimator diameter shifts while being assisted by correctly positioning the main body of the secondary helmet. Having described the science and engineering of Tomosurgery, the following description of the figures illustrate example methods and systems for planning and performing Tomosurgery. FIG. 2 illustrates an example method 200 associated with Tomosurgery planning. FIG. 3 illustrates an example method 300 associated with Tomosurgery planning and delivery. Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity of explanation, the illustrated methods are shown and described as a series of blocks, it is to be appreciated that the methods are not limited by the order of the blocks, as in different embodiments some blocks may occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example method. In some examples, blocks may be combined, separated into multiple components, may employ additional, not illustrated blocks, and so on. In some examples, blocks may be implemented in logic. In other examples, processing blocks may represent functions and/or actions performed by functionally equivalent circuits (e.g., an analog circuit, a digital signal processor circuit, an application specific integrated circuit (ASIC)), or other logic device. Blocks may represent executable instructions that cause a computer, processor, and/or logic device to respond, to perform an action(s), to change states, and/or to make decisions. While the figures illustrate various actions occurring in serial, it is to be appreciated that in some examples various actions could occur concurrently, substantially in parallel, and/or at substantially different points in time. Method 200 may include, at 210, logically dividing a target volume to be radiated into treatment slices. These treatment slices may then be individually radiated. In one example, before logically dividing the target volume into treatment slices, method 200 will determine a treatment slice thickness. Method 200 may also include, at 220, planning a two dimensional path for moving a shaped isocenter through a treatment slice. The isocenter will be produced at the intersection of co-planar beams. Since a target volume may be divided into a set of treatment slices, the planning at 220 may occur for multiple slices. In one example, the shaped isocenter for which the path will be planned will have a disk shape. In one example, the two dimensional path will include a set of scan points to be visited by the isocenter. In one example, the two dimensional path will be a raster scan path. In one example, planning a two dimensional path through a treatment slice includes calculating a resulting dose according to equations described above. Similarly, planning a two dimensional path through a treatment slice may include solving for τ according to equations described above. Method 200 may also include, at 230, planning a three dimensional path for moving the shaped isocenter through the target volume based, at least in part, on two or more of the two dimensional paths. In one example, a shot weight produced by the coplanar beams is modulated by controlling the movement of the isocenter. In addition to moving the isocenter, shot weight may be modulated by controlling one or more of, a number of coplanar beams applied to the target volume, a hole size in a collimator through which at least one of the coplanar beams is to pass, and a temporal delay between one or more of the coplanar beams applied to the target volume. In one example, assembling the three dimensional plan may include solving for a final three-dimensional plan dose according to equations described above. Method 200 may also include, at 240, providing a signal to control a radiosurgery device to deliver radiation using the coplanar beams to the target volume based, at least in part, on the three dimensional path. Providing the signal may include, for example, generating an interrupt, sending a data packet, controlling the voltage on a control line, providing a file that includes path data, providing executable instructions, and so on. In one example, two dimensional paths through treatment slices are to be planned substantially in parallel. In one example, two dimensional paths through different treatment slices may differ in at least one of, scan pattern, importance weighted quadratic objective function, and slice orientation. Additionally, in one example, planning a first two dimensional path through a first treatment slice may begin before a second treatment slice has been defined. The three dimensional plan may reveal issues that went unobserved during two dimensional planning. Thus, method 200 may also include changing a tumor prescription dose between planning two dimensional paths and planning the three dimensional path. In one example, method 200 may also include receiving a pre-operative image(s). The pre-operative image may include a representation of at least a portion of the target volume. Thus, the logical dividing at 210 may include analyzing the pre-operative images. The pre-operative images may be, for example, magnetic resonance images, computed tomography (CT) images, x-ray images, and so on. Method 300 may include some actions similar to those described in connection with FIG. 2. For example, method 300 may include the logical dividing at 310, the 2D path planning at 320, the 3D path planning at 330, and providing a control signal at 340. However, method 300 may also include additional actions. Consider that the delivery apparatus may be dynamically controllable. Control may be exercised for example, over radiation source distance, over the number of collimator openings, over the size of collimator openings, and so on. In one example, control may be done on-the-fly. Thus, method 300 may include, at 350, controlling a delivery apparatus to deliver a set of coplanar beams according to the three dimensional plan. Controlling the delivery apparatus may include, for example, controlling the delivery apparatus to deliver the coplanar beams to two or more treatment slices substantially in parallel. Controlling the delivery apparatus may also include, for example, controlling the opening and closing of collimator holes, controlling the angular velocity of a rotating radiation source, controlling the angular velocity of a rotating blocking device, and so on. The delivery apparatus may provide radiation from radiation sources. Radiation sources may decay over time. Therefore, to improve treatment, method 300 may also include calibrating the delivery apparatus before controlling the delivery apparatus to deliver the radiation using the coplanar beams. With the calibration data acquired, method 300 may also include controlling the delivery apparatus based, at least in part, on the calibration. Calibrating the delivery apparatus may include, for example, acquiring a signal from a polymer gel-MRI dosimeter to which the delivery apparatus applied a set of coplanar beams. Method 300 may also include, in one example, selecting a delivery apparatus to deliver the coplanar beams based, at least in part, on the three dimensional plan. Method 200 and/or method 300 may also include fixing a fiducial marker(s) at a position relative to the target volume. Thus, pre-operative images will include representations of the fiducial markers. Alternatively, method 200 and/or method 300 may simply include receiving pre-operative images that include representations of the fiducials. With the fiducials placed and visible, assembling the three dimensional plan may depend, in one example, on a relationship between an image of a fiducial in a first treatment slice and an image of a fiducial in a second treatment slice. Similarly, with the fiducials placed and visible, control of the delivery device may depend, at least in part, on determining a relationship between a portion of the target volume and another item (e.g., a collimator opening, a radiation source). Use of these fiducials may free example systems from constraints associated with fixed stereotactic frames and/or single session imaging/planning/delivery. While FIGS. 2 and 3 illustrates various actions occurring in serial, it is to be appreciated that various actions illustrated in these figures could occur substantially in parallel. By way of illustration, a first process could logically divide a target volume, a second process could perform 2D planning and a third process could perform 3D planning. While three processes are described, it is to be appreciated that a greater and/or lesser number of processes could be employed and that lightweight processes, regular processes, threads, and other approaches could be employed. FIG. 4 illustrates an example apparatus 400 associated with Tomosurgery planning. Apparatus 400 may include a first logic (e.g., partition logic 410) to logically partition a target volume into a set of treatment slices. The target volume represents a tissue to be subjected to radiation surgery. The radiation may be delivered by a set of coplanar beams. The radiation may be delivered from fixed radiation sources and/or from radiation sources that may move (e.g., circularly) about a target volume. Apparatus 400 may also include a second logic (e.g., 2D logic 420) to determine a set of two dimensional raster scanning paths through the set of treatment slices. The determining may proceed in accordance with the methods and equations described above. The determining may account for whether the path is to be created from fixed radiation sources and/or from moveable (e.g., rotating) sources. Apparatus 400 may also include a third logic (e.g., 3D logic 430) to determine a three dimensional plan to irradiate the target volume to within a pre-determined dose. As described above, the three dimensional plan is to be based, at least in part, on the set of two dimensional raster scanning paths. Once again the determining may account for whether the path is to be created from fixed radiation sources and/or from moveable (e.g., rotating) sources. Apparatus 400 may also include a fourth logic (e.g., control logic 440) to control a delivery apparatus to deliver radiation in a set of coplanar beams to the target volume. The delivery will be made in accordance with the three dimensional path. The control logic 440 may generate a set of signals that are provided to a delivery apparatus. The signals may take different forms, though an electrical signal is preferred. FIG. 5 illustrates an example apparatus 500 associated with Tomosurgery planning and delivery. Apparatus 500 includes elements similar to those described in connection with apparatus 400. For example, apparatus 500 includes a partition logic 510, a 2D logic 520, a 3D logic 530, and a control logic 540. Additionally, apparatus 500 includes a delivery apparatus 550. In one example the delivery apparatus 550 may be a modified Leksell Gamma Knife. In one example, the delivery apparatus 550 may be a Linac unit with a collimator to shape radiation to a slit beam. The delivery apparatus 550 may include a ring-shaped secondary helmet with multiple collimator channels through which multiple beams can focus to an isocenter to form a disk-shaped shot. The delivery apparatus 550 may also include a robotic positioning system that connects a head frame to the ring-shaped secondary helmet. While a head frame and a “helmet” are described, it is to be appreciated that the delivery apparatus 550 may be modified to facilitate Tomosurgery to body parts other than the head. It is to be appreciated that delivery apparatus 550 may be other devices that are capable of producing a substantially planar shot and moving the isocenter of that shot through a treatment slice according to a 2D plan. For example, the delivery apparatus 550 may include a rotating secondary apparatus and/or may include elements to rotate a slit beam around a fixed portion of the delivery apparatus. Since a radiation source(s) may decay, apparatus 500 may include a dosimeter to calibrate the delivery apparatus. In one example, the partition logic 510 may include a logic to receive a set of pre-operative images in which the target volume is represented. The partition logic 510 may then automatically partition the target volume into treatment slices. FIG. 6 illustrates an example computing device in which example systems and methods described herein, and equivalents, may operate. The example computing device may be a computer 600 that includes a processor 602, a memo 604, and input/output ports 610 operably connected by a bus 608. In one example, the computer 600 may include a Tomosurgery logic 630 configured to facilitate planning for Tomosurgery and delivering radiation according to a Tomosurgery plan. In different examples, the logic 630 may be implemented in hardware, software, firmware, and/or combinations thereof. Thus, the logic 630 may provide means (e.g., hardware, software, firmware) for identifying a set of treatment slices in a target volume and means (e.g., hardware, software, firmware) for planning a two dimensional path through a treatment slice. Logic 630 may also provide means (e.g., hardware, software, firmware) for assembling a three dimensional plan for performing radio-surgery on the target volume, and means (e.g., hardware, software, firmware) for controlling a radiosurgery delivery apparatus to move the intersection of the coplanar radiation beams through the target volume according to the three dimensional plan. While the logic 630 is illustrated as a hardware component attached to the bus 608, it is to be appreciated that in one example, the logic 630 could be implemented in the processor 602. The means described in connection with logic 630 may determine an optimal slice thickness using the following inputs, algorithms, and outputs. Input: Calculated 3D dose kernel d of a disk-shaped shot. Origin/center of d(x, y, z) set to (0, 0, 0). Algorithm: (1) Calculate the cross-sectional dose profile Dcs of the 3D dose bar by projecting d (x, y, z) to y-z plane. Here, Dcs is a function of y and z. (2) Find the FWHM of Dcs(y=0, z). Output: The FWHM approximately equals to the optimal treatment slice thickness, Topt. The means described in connection with logic 630 may interpolate the 3D volume data of segmented tumor and critical section (CS) using the following inputs, algorithms, and outputs. Input: Binary (BW) volume data of segmented tumor and CS, as Vt and Vcs respectively. Sizes of Vt and Vcs, Dim_t and Dim_cs, and their voxel sizes, VOXS_t and VOXS_cs. Real volume values. Algorithm: (1) Use cubic interpolation to resample Vt and Vcs to the smaller voxels, 0.25×0.25×0.25 mm3.→grayscale volume data, VI_t and VI_cs, which have the enlarged dimensions than the original volume sizes (Dim_t and Dim_cs). (2) Use 3D smoothing kernel to smooth VI_t and VI_cs→VS_t and VS_cs. (3) Find the best threshold TH_OPT where the thresholded tumor volume and CS volume close to the real volumes. The search of the best threshold can be performed through binary search approach: a. Testing the middle of an interval (initially 0-1) b. Eliminating a half of that interval c. Repeating the procedures a-c on the other half of that interval. Termination condition: the difference between the old and new threshold values<the pre-defined tolerance value. (4) Perform thresholding on VI_t and VI_cs by using the threshold TH_OPT.Output:Binary volume data for resampled tumor and CS, VO_t and VO_cs. The means described in connection with logic 630 may determine a raster scan format using the following inputs, algorithms, and outputs. Input: Tumor and CS volume data, VO_t, and VO_cs. Tumor volume thickness T and the optimal treatment slice thickness Topt. Algorithm: (1) Based on equation T=Topt×N+R, calculate R and N. (2) Divide the tumor volume along the z direction to a serial N adjacent treatment slices (with the thickness as Topt) starting from the superior side. The middle x-y plane of each treatment slice is the corresponding raster-scan plane. The locations of the raster-scan planes in z are recorded in an N-sized array, raster_z. (3) If R=0, go to (4); otherwise, append a new entry onto the array raster_z (now, the array size becomes N+1). The value of new entry, raster_z(N+1)=raster_z(N)+R. The total number of the raster-scan planes is denoted as n (=N or N+1). (4) For each treatment slice, project tumor tissues and CS tissues onto the corresponding raster-scan plane. The projected images are denoted as Proj_t and Proj_cs for tumor and CS tissues respectively. (5) Place the raster lines within the tumor projection regions but not in the CS projection regions. Record the location of each raster-scan point into the array raster_points(x, y, z).Output:The locations of raster-scan points, raster_points array. The means described in connection with logic 630 may perform a first stage optimization using the following inputs, algorithms, and outputs. Input: raster_points array. Tumor and CS volume data, VO_t and VO_cs. Prescribed dose for tumor, PRESCRIPTION_DOSE=1. Dose tolerance of normal tissues (NT), TOLERANCE_NT=0.2. Dose tolerance of CS, TOLERANCE_CS=0.2. Important factors to tumor, NT, and CS, IF_T, IF_NT, and IF_CS. Virtually adjusted prescribed dose, VPD (fixed to 0.8 here). Algorithm: τ j k + 1 = τ j k ( ∑ tissue ⁢ ∑ i ⁢ I i · d ji · D i P ) · ( ∑ tissue ⁢ ∑ i ⁢ I i · d ji ⁢ D i d ( k ) ) - 1 (1) Calculate τ for raster points based on the iterative equation. (2) Terminate iterative procedure when the tumor killing ratio becomes worse.Output:Array raster_weight, which records τ of each raster point. The means described in connection with logic 630 may pre-process for the second stage optimization using the following inputs, algorithms, and outputs. Input: Arrays, raster_weight and raster_points. Shot dose kernel d. Algorithm: For the i-th treatment slice: (1) Allocate computer memory DS(i) as a 3D matrix. DS(i) has the thickness of 3×Topt in z. (2) Calculate the 3D dose distribution resulted from the i-th planar raster scanning. The resulted dose distribution is saved into DS(i). The dose distribution is calculated based on 3D convolution of d and raster_weight.Output:Totally n DS matrices. The means described in connection with logic 630 may perform a second stage optimization using the following inputs, algorithms, and outputs. Input: n DS matrices. Arrays raster_weight and raster_points. Tumor and CS volume data, VO_t and VO_cs. Prescribed dose for tumor, PRESCRIPTION_DOSE=1. Dose tolerance of normal tissues (NT), TOLERANCE_NT=0.2. Dose tolerance of CS, TOLERANCE_CS=0.2. Important factors to tumor, NT, and CS, IF_T, IF_NT, and IF_CS. Virtually adjusted prescribed dose, VPD. Algorithm: w i k + 1 = w i k ( ∑ tissue ⁢ ∑ n ⁢ I · D i s · D f P ) · ( ∑ tissue ⁢ ∑ n ⁢ I i · D i s ⁢ D f d ( k ) ) - 1 (1) Calculate w for each treatment slice based on the iterative equation. (2) Terminate iterative procedure when the tumor killing ratio and CS survival (if applicable) becomes worse. (3) For each treatment slice, adjusting the shot speed:raster_weight=raster_weight×w. Output:The adjusted raster_weight array. The adjusted shot weights (speed) can now be used to calculate the dose distribution of the final treatment plan. Generally describing an example configuration of the computer 600, the processor 602 may be a variety of various processors including dual microprocessor and other multi-processor architectures. A memory 604 may include volatile memory and/or non-volatile memory. Non-volatile memory may include, for example, ROM, PROM, EPROM, and EEPROM. Volatile memory may include, for example, RAM, synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), and direct RAM bus RAM (DRRAM). A disk 606 may be operably connected to the computer 600 via, for example, an input/output interface (e.g., card, device) 618 and an input/output port 610. The disk 606 may be, for example, a magnetic disk drive, a solid state disk drive, a floppy disk drive, a tape drive, a Zip drive, a flash memory card, and/or a memory stick. Furthermore, the disk 606 may be a CD-ROM, a CD recordable drive (CD-R drive), a CD rewriteable drive (CD-RW drive), and/or a digital video ROM drive (DVD ROM). The memory 604 can store a process 614 and/or a data 616, for example. The disk 606 and/or the memory 604 can store an operating system that controls and allocates resources of the computer 600. The bus 608 may be a single internal bus interconnect architecture and/or other bus or mesh architectures. While a single bus is illustrated, it is to be appreciated that the computer 600 may communicate with various devices, logics, and peripherals using other busses (e.g., PCIE, SATA, Infiniband, 1394, USB, Ethernet). The bus 608 can be types including, for example, a memory bus, a memory controller, a peripheral bus, an external bus, a crossbar switch, and/or a local bus. The computer 600 may interact with input/output devices via the i/o interfaces 618 and the input/output ports 610. Input/output devices may be, for example, a keyboard, a microphone, a pointing and selection device, cameras, video cards, displays, the disk 606, the network devices 620, and so on. The input/output ports 610 may include, for example, serial ports, parallel ports, and USB ports. The computer 600 can operate in a network environment and thus may be connected to the network devices 620 via the i/o interfaces 618, and/or the i/o ports 610. Through the network devices 620, the computer 600 may interact with a network. Through the network, the computer 600 may be logically connected to remote computers. Networks with which the computer 600 may interact include, but are not limited to, a local area network (LAN), a wide area network (WAN), and other networks. To the extent that the term “includes” or “including” is employed in the detailed description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed in the detailed description or claims (e.g., A or B) it is intended to mean “A or B or both”. The term “and/or” is used in the same manner, meaning “A or B or both”. When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). To the extent that the phrase “one or more of, A, B, and C” is employed herein, (e.g., a data store configured to store one or more of, A, B, and C) it is intended to convey the set of possibilities A, B, C, AB, AC, BC, and/or ABC (e.g., the data store may store only A, only B, only C, A&B, A&C, B&C, and/or A&B&C). It is not intended to require one of A, one of B, and one of C. When the applicants intend to indicate “at least one of A, at least one of B, and at least one of C”, then the phrasing “at least one of A, at least one of B, and at least one of C” will be employed.
041586034	abstract	In a blow-off device for limiting excess pressure in nuclear power plants, at least one condensation tube disposed so that a lower outlet end thereof is immersed in a volume of water in a condensation chamber having a gas cushion located in a space above the volume of water, and the upper inlet end of the condensation tube extending out of the volume of water and being connectible to a source of steam that is to be condensed or a steam-air mixture, the outlet end of the condensation tube, for smoothing the condensation, being provided with wall parts forming passages extending in axial direction, delimited from one another and terminating in the water volume, the wall parts serving to subdivide steam flow from the source thereof and bubbles produced thereby in the water volume, the wall parts being constructed as a tube attachment and being formed with an opening corresponding to the outlet end of the condensation tube and by means of which the tube attachment is mounted on the outlet end of the condensation tube, a first group of the wall parts in the tube attachment being disposed in alignment with the outlet end of the condensation tube, and a second group of the wall parts surrounding the first group thereof, the passages formed by the second group of the wall parts communicating laterally with the passages formed by the first group of the wall parts, the passages formed by the second group of the wall parts, at least at the upper ends thereof, communicating with the water volume.
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049892266	summary	BACKGROUND OF THE INVENTION This invention relates to a method of producing curvature on the surface of a substrate through selective removal of material from the substrate and selective application of stress-producing materials to the substrate. The use of lenses and mirrors to focus and direct visible light and other electromagnetic radiation is well established. Conventional lenses and mirrors, however, are not effective for focusing or directing electromagnetic radiation having short wavelengths, such as x-rays and short-wave ultraviolet rays. It is known that short wavelength radiation is strongly reflected from reflective surfaces if the angle of incidence to the surfaces is low, for example, less than five degrees for one nanometer (nm) or shorter wavelength x-rays. Employing such so-called grazing incidence techniques, however, is only effective if suitably uniform and smooth reflective surfaces can be found, and this has proved difficult to do. Use of conventional polished or mirrored surfaces, prepared using known grinding and polishing techniques, generally does not provide the desired control and accuracy in reflecting short wave radiation. One approach to achieving better control and accuracy in reflecting x-rays, even at larger angles of incidence, is to use so-called Bragg reflection--reflection of radiation from planes of a crystal. The drawback of this has, until recently, been that only very short wavelength x-rays (less than one nanometer) could be reflected. Recently, however, multi-layered thin film structures have been employed for reflecting longer wavelength x-rays. Such reflection occurs at the interfaces of adjacent films having different refractive indices. The layers can be selected so that reflected waves add constructively to produce a strong total reflection. In order to focus electromagnetic radiation using reflection, it is necessary to provide an appropriate curved surface capable of reflecting the radiation. Currently used focusing devices are constructed either by lathing, grinding or otherwise abraiding a surface of a reflector element into a curved surface, or by casting a reflector element on a curved mandrel. Among the problems with these approaches are the difficulty of obtaining desired curvatures, the roughness of the resulting curved surface, and the time required to prepare the elements. Polishing, of course, would be performed to smooth out the surface, but remaining irregularities would preclude or discourage use of the surface for focusing shorter wave radiation such as x-rays. SUMMARY OF THE INVENTION It is an object of the invention to provide a method of producing a smooth curved surface of a desired shape suitable for, but not limited to, use as an optical focusing blank for short wavelengths such as x-rays. It is also an object of the invention to provide such a method which is relatively easy and inexpensive to carry out. It is a further object of the invention to provide such a method wherein the degree of curvature can be precisely controlled. It is another object of the invention to provide a precision focusing structure for radiant energy. The above and other objects are realized in a specific illustrative embodiment of a method of producing curvature on a working surface of a substrate. The substrate, which may be a crystalline or amorphous material, has a working side and surface, and a second side and oppositely facing surface from which substrate material is removed according to a predetermined pattern. The removal of material may be carried out by etching or even by cutting or abraiding with a cutting or abrasive tool. A stress producing film is applied to at least one of the surfaces to cause the substrate to bend and produce the desired curvature in the working surface. The amount and shape of the curvature is determined by the substrate thickness at the bottom of the removed material pattern, the shape of the areas from which material is removed, and the stresses (dependent in part on the thickness) of the film. The film may be selected to produce tensile stress or compressive stress on the substrate, and placed on either or both sides of the substrate to cause the desired bending. Although the above discussion concerned the use of the curved surface for focusing electromagnetic waves, the curved surface structure might also be used as molds for machinery, tools, etc., as specially shaped support structure for electrical circuitry, as electromagnetic radiation detectors, or as diffraction gratings.
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	description	This application is a Continuation of copending PCT International Application No. PCT/JP2008/063557 filed on Jul. 29, 2008, which designated the United States, and on which priority is claimed under 35 U.S.C. §120. This application also claims priority under 35 U.S.C. §119(a) on Patent Application No. 2007-197130 filed in Japan on Jul. 30, 2007, all of which are hereby expressly incorporated by reference into the present application. The present invention relates to a Doppler reactivity coefficient measuring method and, more specifically, to a Doppler reactivity coefficient measuring method for directly measuring Doppler reactivity coefficient utilizing nuclear reactor physics test data. In a commercial nuclear power plant, for example, in a pressurized water reactor (hereinafter referred to as “PWR” in principle), in order to ensure safe and cost-efficient operation, reactor core design is carried out before each cycle of operation to consider various matters such as how to arrange fuel assemblies each having different burn-up and hence different reactivity in the reactor core and whether or not self-regulating characteristics of the reactor core are sufficient. During periodic inspections between each cycle, nuclear reactor physics tests (start-up reactor physics tests) are performed to measure and evaluate reactor physics characteristics of the reactor core for the current cycle operation. For example, during the tests, whether or not the designed reactor core achieves critical through prescribed operations is determined, and reactivity variation when control rods are moved with respect to the reactor core and reactivity variation when moderator temperature is changed are measured, to confirm the validity of the reactor core design. Here, the self-regulating characteristics refer to characteristics that when reactivity of the reactor core varies by some cause or other and s as a result, a phenomenon acting in the reverse direction naturally occurs in the reactor, that is, so-called negative reactivity feedback, which is a very important factor ensuring safe operation of a nuclear reactor. In a PWR, fuel temperature reactivity coefficient, that is, reactivity variation of the nuclear reactor caused by fuel temperature variation, and moderator temperature reactivity coefficient, that is, reactivity variation of the nuclear reactor derived from moderator temperature variation, are both negative (if the temperature rises, negative reactivity is added), and thus the PWR exhibits the self-regulating characteristics. In a boiling water reactor (hereinafter referred to as “BWR” in principle), the self-regulating characteristics are exhibited additionally by the phenomenon (effect) that the number of neutrons slowed down by cooling water decreases, as the bubbles in the cooling water increases when temperature rises. The fuel temperature reactivity coefficient mentioned above is governed by a phenomenon called Doppler effect. Doppler effect refers to a phenomenon that if temperature rises, nuclide existing in the fuel increases resonance absorption of neutrons, so that the number of neutrons contributing to nuclear fission decreases and, as a result, core reactivity lowers. The ratio of the reactivity variation to unit temperature change is referred to as Doppler reactivity coefficient. In U238 that occupies a great part of uranium fuel used in existing light water reactors, the effect is significant since U238 exhibits strong resonance absorption of neutrons. This effect realizes the function of decreasing reactor power if the temperature of nuclear fuel increases. In addition, this effect realizes rapid time response, since it reflects temperature variation of fuel more directly in a short period after reactor power variation rather than that of the moderator. Hence, in a PWR, this effect is believed to play a key role in realizing safe operation, since PWR lacks the effect attained by the increase of bubbles in cooling water, which is attained in a BWR The relation between the fuel temperature variation and the reactivity in a commercial nuclear power plant is evaluated by using, temperature dependent nuclear reactor cross section data obtained by measurements of relation between the nuclear fuel temperature variation and nuclear reaction such as neutron absorption. It is noted, however, that in the nuclear reactor physics tests, the fuel temperature reactivity coefficient is not directly measured, since it is difficult to directly measure the fuel temperature and if fuel temperature is changed, other parameters including the moderator temperature would also be changed. Conventionally Doppler reactivity coefficient is evaluated by neutronics characteristics analysis at the time of nuclear core design. As long as the conventional fuel are used, Doppler reactivity coefficient can be evaluated with high accuracy based on knowledge and experiences accumulated for a long history (paragraphs 0003 and 0004 of Patent Document 1). In order to realize safe operation of nuclear reactor with higher reliability, it is preferred to directly measure Doppler reactivity coefficient, as part of the verification of core design. It is more important particularly for PWRs, in which full-scale utilization of MOX fuel and high burn-up fuel within a few years is planned. In countries outside Japan, direct measurements of the relation between fuel temperature variation and reactivity variation, that is, fuel temperature reactivity coefficient, were made several times in 1950s in research reactors. In such measurements, temperature of small spheres made of metal uranium or uranium oxide was increased under soft neutron spectrum conditions with few fast neutrons, and reactivity variation was measured (Non-Patent Documents 1 and 2). In Japan, using FCA (Fast Critical Assembly: very small nuclear reactor) of Japan Atomic Energy Agency, in 2005, only the uranium oxide fuel or MOX fuel was loaded in soft neutron spectrum field, temperature was increased and reactivity variation was measured (Non-Patent Document 3). The data obtained by the above-described measurements using actual reactors and the like are important for expanding database and for verifying general-purpose nuclear design codes. However, the nuclear reactors used for the actual measurements are very small and much different in shape and structure from commercial nuclear power plants. Therefore, the validity of core design and the verification of code design codes directed to large scale commercial nuclear power plants that require higher accuracy are attained not directly but indirectly. For this reason, technology that enables direct measurement of Doppler reactivity coefficient particularly of a PWR has been long desired. Tsuji, one of the inventors of the present invention, at last developed the method recently (Patent Document 1). According to this method, basically, isothermal temperature reactivity coefficient measurement method and dynamic identification are combined for measuring fuel temperature reactivity coefficient. Generally, the method includes the steps (process steps) described below. Here, “isothermal temperature reactivity coefficient” refers to the sum of reactivity coefficient related to fuel temperature only (obtained by partial differentiation by fuel temperature) and reactivity coefficient related to moderator temperature only (obtained by partial differentiation by moderator temperature). In the isothermal temperature reactivity coefficient measurement, moderator temperature is slowly increased or decreased without fission energy while the nuclear reactor is in critical but substantially zero power state. In this experiment, fuel temperature follows quasi-statically or isothermally moderator temperature (this means that fuel temperature is nearly equal to moderator temperature), because the fission energy is negligible and the changing rate of moderator temperature is very slow. As the temperatures change, the reactivity also changes. First, form the measurement mentioned above, the isothermal temperature reactivity coefficient is obtained as the ratio of reactivity variation to moderator temperature variation. Next, control rods are withdrawn to add external reactivity, whereby reactor power is increased, for example, by about 1% of the rated power. At this time, time changes of added external reactivity, ex-core neutron detector response, inlet coolant (moderator) temperature and average coolant (moderator) temperature are measured and time-series data of them are collected. Further the ex-core neutron detector response is input to a digital reactivity meter, to obtain transient of nuclear reactor reactivity. From the resulting time-series data, fuel temperature reactivity coefficient is calculated using dynamic identification. Specifically, the measured time series data are converted into frequency response expressions by numerical Fourier Transform to apply a dynamic identification method in a frequency domain. Doppler reactivity coefficient is determined so as to reproduce the frequency responses of measured data in the frequency transfer response of the reactor kinetics model through the least square fitting (basically, by the least square method). It is note that moderator temperature reactivity coefficient can be calculated by subtracting Doppler reactivity coefficient from isothermal temperature reactivity coefficient. Dynamics Identification in a frequency domain refers to a method of estimating a frequency transfer function G(ω) that establishes a frequency response relation between the input and output frequency responses, u(ω) and x(ω) at the frequency ω that are converted from time series data u(t) and x(t) by numerical Fourier Transform, and thereby finding g(t) (solving the function equation), when a known function u(t) is input to a fully or partially unknown function g(t) and an output function x(t) is known, Patent Document 1: JP2006-84181A Non-Patent Document 1: E. Creutz, et al., “Effect of Temperature on Total Resonance Absorption of Neutrons by Spheres of Uranium Oxide,” J. Apple. Phys. 26, 276 (1955) Non-Patent Document 2: R. M. Pearce et al., “A Direct Measurement Uranium Metal Temperature Coefficient of Reactivity,” Nucl. Sci. Eng., 2, 24 (1957) Non-Patent Document 3: JAERI-Research, 2005-026 issued by Japan Atomic Energy Agency The above-described method of directly measuring Doppler reactivity coefficient requires numerical Fourier transform, that is, transform to frequency data and, therefore, application to discontinuous data (i.e. data with some intermittent time intervals where measured data are unavailable for measuring Doppler reactivity coefficient) is difficult. As a result, when there is frequent range switching of NIS (Neutron Instrumentation system: ex-core neutron detector) or movement of control rod bank, which causes noise mixture and significant fluctuation in measurement values, application of this method becomes very difficult. Therefore, a method of measuring Doppler reactivity coefficient of a nuclear reactor, which enables easy measurement and is applicable to discontinuous data, has been desired. The present invention was made in order to solve the above-described problems, and, according to the invention, initial reactivity ρin is applied from a subcritical but very close to critical state, thereafter reactor power is increased with a constant reactor period at the beginning and the increasing rate gradually reduces due to temperature reactivity feedback. The contribution of reactivity feedback is read from variation in reactivity ρp corresponding to the constant reactor period (reactivity of constant reactor period, that is, reactivity added as the power increased at a constant rate in a logarithm scale, when reactor core achieves from sub-critical to super critical). The reactor power is increased until reactivity compensation effect induced by temperature reactivity feedback becomes noticeably large and then is decreased by inserting control rod bank “Reactor period” refers to a time period in which the power of nuclear reactor attains to e (about 2.718) times higher. Here, the following points are taken into consideration. As a reactor initial condition before the measurement is started, a sub-critical but very close to critical state at a final process step approaching to the criticality is used. In this condition, all the control rod banks except one bank are fully withdrawn, the boron concentration of moderator (coolant) is diluted close to the critical boron concentration, and the criticality is attained if partially inserted control rod bank is withdrawn with few steps (for example, in Westinghouse type PWRs, total movable steps of control rod is 228). Further, as the means for reading contribution of reactivity feedback, the values ρin and ρp are subjected to simulation analysis in a low power range that yields little feedback, and values that reproduce actually measured NIS signals are searched and determined. Specific process procedure for the measurement includes six steps of: collecting data; removing γ-ray influence from collected neutron flux data; extracting reactivity feedback contribution component; determining upper limit attained reactor power; calculating average fuel rod temperature; and estimating Doppler reactivity coefficient. In the following, contents of each step will be described in detail, using mathematical expressions. [Preconditions] As preconditions for the measurement, it is assumed that values detected by ex-core neutron detector of the power range, average cooling water temperature of the nuclear reactor as the object are measurable as time-series data, and data necessary for core analysis are all available. Therefore, for example, one-point reactor kinetic parameters βi and λi (where i represents six-group delayed neutrons; i=1, . . . 6), importance power-averaged correction factor {factor used for converting volume-averaged value of fuel rod calculated by one-point reactor kinetic model to average temperature weighted by neutron flux distribution and adjoint neutron flux (neutron importance) distribution} of fuel rod temperature, control rod bank operation history are fairly accurately known or approximately known from separate theoretical analysis or from operation records. Further, from the isothermal temperature coefficient measurement test performed prior to the present measurement, isothermal temperature reactivity coefficient (=Doppler reactivity coefficient+moderator temperature reactivity coefficient) is also known. In addition to the above, various coefficients including Doppler reactivity coefficient of fuel as the object of measurement, initial sub-criticality and the like are approximately known from theoretical analysis at the time of design and from past experiences. Therefore, when an error function is evaluated in a dynamic identification method, these approximate values are often input as initial values, or close values thereof are often input. [Step of Collecting Data] From a nuclear reactor (PWR) in a sub-critical state, control rods are withdrawn by a prescribed amount to attain super critical and low power state, and series of variations in the neutron flux and average moderator temperature are continuously collected as time-series data. Here, sub-criticality ρsub can be back-calculated from the reactivity ρin applied as the control rods are withdrawn by a prescribed amount, and from reactivity ρp of constant reactor period. A commercial reactor provides some level of neutron numbers even in sub-critical state due to neutrons emitted by external neutron sources and from spent fuels. Further, the critical state refers to a state of equilibrium in which the number of neutrons released by fission in the reactor is equal to the number of neutrons lost by absorption in the reactor and leaving to the outside of the reactor (effective multiplication factor is 1), and the (thermal) output in the reactor is determined depending on the level of neutron numbers where the state of equilibrium is attained. (Removal of γ-Ray from Neutron Flux Data) As described above, when variations of neutron flux in a nuclear reactor of which power is extremely low as compared with the rated power and hence neutron flux is small are to be collected as time-series data, some correction procedure is required. Specifically, γ-rays are emitted from activated structure materials around detectors. Ex-core neutron detectors used in the zero power reactor physics test are uncompensated ionization chambers equipped as a power range monitor in NIS (Nuclear Instrumentation System) and react to γ-rays. There is always a constant dose of γ-ray derived from the spent nuclear fuel even at the time of zero-power test. On the other hand, the neutron flux in the reactor during the zero-power test is at a low level, since the reactor power is low. As a result, at the time of zero-power test, the background component contained in collected data or the noise caused by γ-ray is not negligible. After the reactor power increases substantially, the number of neutrons generated in the reactor increases and, therefore, the influence of γ-ray becomes small enough to be negligible. Therefore, in the zero-power test, the influence of γ-ray, that is, the component (noise) caused by γ-ray erroneously collected as neutrons, is removed from the data of NIS signal obtained by using an ionization chamber, utilizing the characteristic that the component resulting from γ-ray is almost constant regardless the reactor power. It is noted that when a PWR to be constructed in the future is devised to enable direct measurement of neutrons free from the influence of γ-ray, this operation would be unnecessary. The specific method is as follows. First, neutron flux that corresponds to the reactor power is converted and obtained as the current data. Thereafter, based on the obtained data, an error function E(gc, ρp) representing an error between the value numerically evaluated by digital simulation of low reactor power transient and the actually measured value is defined by Equation (1) below. Then, γ-ray mixture rate (the ratio of mixed noise component to the genuine neutron signal corresponding to the initial reactor power) gc is plotted on the X-axis, reactivity of constant reactor period ρp is plotted on the Y-axis, and the error function E(gc, ρp) is plotted on the Z-axis. Further, using gc and ρp as parameters, a combination of points gc and ρp that minimizes the value E(ge, ρp) is found (such an operation of finding parameter values of which error function attains the minimum basically based on the least squares method is also referred to as “fitting”). The value gc found in this manner serves as the actual γ-ray mixture rate. Here, the error function is given as a logarithm (ln), considering that the reactor power increases exponentially with time. E ⁡ ( g c , ρ P ) = 1 N ⁢ ∑ i = 1 N ⁢ { ln ⁢ ( P s ⁡ ( t i ) + g c ⁢ P 0 s P 0 s + g c ⁢ P 0 s ) - ln ⁡ ( P m ⁡ ( t i ) P 0 m ) } 2 [ Equation ⁢ ⁢ 1 ] In the equation above, P represents reactor power, upper suffixes s and m represent an analytical value and a measured value, respectively, t represents time, N represents the number of data, ti represents time corresponding to data i, 0 represents an initial value (t=0), and the core is sub-critical. As the measured value of reactor power, the NIS signal is used, assuming that the NIS signal is in proportion to the reactor power. Since the reactor power response necessary for the analysis above is in the low power range in which contribution to reactivity feedback is negligible and since only the relative variation reactor power response with respect to the initial power is required, the initial reactor power Ps0 may be set arbitrarily as long as these conditions are satisfied. Absolute value response of reactor power is determined by a processing method that will be described later. The output data with the γ-ray removed, reconfigured from the actually measured NIS signal, is given by Equation (2) below: P g m ⁡ ( t ) = ( P 0 s + g c ⁢ P 0 s P 0 m ) ⁢ P m ⁡ ( t ) - g c ⁢ P 0 s [ Equation ⁢ ⁢ 2 ] Accordingly, the width of reactor power variation Rzm can be calculated in accordance with Equation (3) below, from the initial power Pmg(0) and from the maximum reactor power Pmg,max[max{Pmg(t)}], that is attained at the time just before control rod bank is inserted to reduce reactor power after a large temperature reactivity feedback effect is observed in reactivity transient (hereinafter the maximum power is referred to as “upper limit reactor power”). A commercial power reactor provides some level of neutron numbers even in the sub-critical state as described above and, therefore, the denominator of Equation (3) is not zero. R zm = P g , max m P g m ⁡ ( 0 ) [ Equation ⁢ ⁢ 3 ] With the reactivity of constant reactor period ρp the initial sub-criticality ρ0sub can be obtained from Equation (4).ρsub0=ρin−ρP [Equation 4] In each iteration process in the least square fitting for determining gc and ρp, the strength of external neutron source term in the one-point reactor kinetics equation is reevaluated using a modified value of ρp as −ρ0subPs0/Λ where Λ is the neutron generation time. Here, the applied initial reactivity ρin from positions control rods before and after movement can be estimated from control rod bank reactivity worth that is measured experimentally in a routine test of the zero power reactor physics test or evaluated numerically with reactor design codes. (Extraction of Reactivity Feedback Contribution Component) From the time-series data of reactor power with γ-ray removed, time-series data of reactivity ρ is calculated by inverse kinetic method with respect to one-point reactor kinetic equation. The reactivity feedback contribution component Δρfd is obtained by subtracting ρin from reactivity variation ρ(t) as represented by Equation (5).Δρfd(t)=ρ(t)=ρin [Equation 5] On the other hand, the reactivity feedback contribution component Δρfd is a sum of contributions of Doppler reactivity feedback coefficient αf and moderator temperature reactivity feedback, and represented by Equation (6) below:Δρfd(t)=αf(βTf,av(t)−ΔTc,av(t))+αitcΔTc,av(t) [Equation 6] Here αf and αiitc represent Doppler reactivity coefficient and isothermal temperature reactivity coefficient, ΔTf,av represents change amount of average fuel rod temperature, and ΔTc,av represents change amount of average moderator temperature. The reactivity contribution component Δρfc {component of the first term on the right side of Equation (6)} related to Doppler reactivity coefficient αf can be represented by Equation (7) below. This component is calculated form measured overall temperature reactivity feedback contribution Δρfd obtained from Equation (5), measured change amount ΔTc,av of average moderator temperature and measured isothermal temperature reactivity coefficient αitc.Δρfc(t)=Δρfd(t)−αitcΔTc,av(t) [Equation 7] On the other hand, Δρfc has the relation of Equation (8) with the average fuel rod temperature and, therefore, if the average fuel rod temperature can be evaluated, Doppler coefficient αf can be estimated.Δρfc(t)=αf(ΔTf,av(t)−ΔTc,av(t)) [Equation 8] If the actual reactor variation is known, the change of average fuel rod temperature ΔTf,av(t) can be numerically evaluated from fuel rod heat conduction equation, using actually measured average moderator temperature Tc,av(t). Specifically, in a general PWR, sensors for measuring coolant (moderator) temperature are installed in coolant pipes near the inlet and outlet, respectively, of the reactor core, and the values measured by these sensors are output through an averaging circuit as coolant (moderator) temperature. From the signal obtained by removing γ-ray from the NIS signal, it is possible to determine the ratio Rzm of the upper limit reactor power to the initial power, while it is impossible to determine the absolute value of the power. Here, if the core inlet moderator temperature is constant or if it is measured, the reactor power can be obtained by evaluating the difference between the core inlet and outlet temperatures from actually measured average moderator temperature Tc,av. When reactor power changes, however, the balance between heat supply from the reactor core and heat removal on the secondary side of cooling loop steam generator is temporarily lost, of which influence appears as a variation in core inlet temperature. Thus, assumption of constant core inlet temperature is not applicable. As mentioned before, temperature sensors are installed in coolant pipes near the inlet and outlet of the reactor core to measure the average moderator temperature. Therefore if the signal line of the inlet temperature sensor is connected to a data acquisition system, the time-series data of inlet moderator temperature are available and the reactor power can be determined from the measured inlet and average moderator temperatures. However this requires a change of normal procedure of the zero power reactor physics test. As a general trend electric power companies are reluctant to change established routine test procedure from possibility that if might cause unexpected troubles in the startup period. In the present invention, based on the reasons mentioned above, a method for measuring Doppler reactivity coefficient with standard measurement devices in conventional testing processes of zero power reactor physics test is proposal. In the case where the time series data of inlet moderator temperature are available, the process for determine the actual reactor power that will be explained below can be skipped. In order to measure Doppler reactivity coefficient by a conventional measuring system, heat removal model in a primary coolant loop of PWR such as shown in FIG. 1 is incorporated in a nuclear reactor kinetic simulation model, whereby the absolute value of reactor power change is obtained. (Primary Cooling Loop Heat Removal Model) Referring to FIG. 1, reference character 10 denotes a reactor core, 20 a steam generator, 30 a cooling water circulation pump, 41 a reactor outlet side pipe, 42 a reactor inlet side pipe, arrows represent moderator (cooling water) flow and thick white arrows represent heat flow. The simulation model simulating the heat removing behavior of primary coolant loop is configured from heat transport equation and energy conservation equation on average coolant temperatures of reactor inlet and outlet pipes, average coolant temperature on the primary side of steam generator and average coolant temperature of cooling pump compartment. (Determination of Upper Limit Reactor Power) The most important parameter determining the cooling characteristics of primary coolant loop is a time constant τsg,12 related to heat transfer from the primary side to the secondary side of steam generator, which must be determined. Different from a small nuclear reactor such as a materials test reactor or a critical test facility, a large scale nuclear reactor for power generation, for example, a PWR, has a heat exchanger such as a steam generator. Therefore, usually there is a time difference between the peak time of neutron flux data and the peak time of temperature of moderator such as the cooling water. Noting that there is a direct relation between the time difference and the time constant τsg,12 and that there is a strong correlation between the upper limit reactor power and the maximum temperature of average moderator temperature Tc,av, the upper limit reactor power and τsg,12 are determined. In order to evaluate the difference between peak times of power and temperature measurement values by the least squares fitting method, an error function given by Equation (9) is introduced, using initial power P0{=P(0)} and time constant τsg,12 related to heat transfer as parameters. In Equation (9), upper suffixes s and m represent analytical value and measured value, respectively. E ⁡ ( τ sg , 12 , P 0 ) = ( 1.0 - t p s t p m ) 2 + ( 1.0 - Δ ⁢ ⁢ T c , av s Δ ⁢ ⁢ T c , av m ) 2 [ Equation ⁢ ⁢ 9 ] Here, tp represents maximum temperature time of average moderator temperature Tc,av, and ΔTc,av represents temperature variation width when maximum temperature is attained (temperature increase from sub-critical state). Conditions under which the error function E(τsg,12, P0) attains the minimum, that is, the values of time constant τsg,12 and the initial power P0 with which the moderator maximum temperature time and the maximum width of increase of average moderator temperature both become equal to the actually measured values, are calculated in the similar manner as the least squares fitting using Equation (1) above. Upper limit reactor power Pmax is assumed to be the maximum reached reactor power calculated from simulation analysis with (τsg,12, P0) minimizing the error function E. In each iteration process of the least squares fitting, P0 is reevaluated from Equation (3) using Pmax modified in the respective iterations. (Determination of Average Fuel Rod Temperature Variation) Using the maximum reached reactor power Pmax and the width of reactor power variation Rzm determined in the above-described manner, reactor power response from the initial power to the maximum reached reactor power is determined, from the NIS signal with γ-ray noise removed. By inputting the reactor power response and the actually measured average moderator temperature Tc,av to the heat transfer equation related to average fuel rod temperature, the average fuel rod temperature variation ΔTf,av(t) is determined. (Calculation of Effective Average Fuel Temperature) Average temperature of fuel increases/decreases in accordance with the reactor power, and the temperature variation is large and rapid as compared with the moderator. Introducing the first-order perturbation theory to examine reactivity response to fuel temperature variation, the average fuel temperature variation ΔTf,av(t) is given as importance power-averaged value ΔTl,ipf,av(t) represented by Equation (10) below. Here, the first-order perturbation theory is used from the following reason: the perturbation theory is to put a small variation and to consider the influence of the variation. In evaluating the influence of variation with the first-order perturbation theory, higher products more than the second between various perturbations induced by the variation are neglected because they are negligible and the influence is evaluated only with the first-order perturbations. It is superior as a method of evaluating correctly reactivity variation by explicitly taking into account the local effect of fuel temperature distribution. Thus, application of perturbation theory is considered appropriate, as the fuel temperature variation is small at the time of reactor physics test. Δ ⁢ ⁢ T f , av ip ⁡ ( t ) = ( ∫ V ⁢ ϕ † ⁡ ( r ) ⁢ Δ ⁢ ⁢ T f ⁡ ( r , t ) ⁢ ϕ ⁡ ( r ) ⁢ ⁢ ⅆ V ∫ V ⁢ ϕ † ⁡ ( r ) ⁢ ϕ ⁡ ( r ) ⁢ ⁢ ⅆ V ) [ Equation ⁢ ⁢ 10 ] The average fuel temperature variation ΔTf,av(t) calculated by the one-point reactor kinetic model is a volume-averaged value as represented by Equation (11) below: Δ ⁢ ⁢ T f , av = ( ∫ V ⁢ Δ ⁢ ⁢ T f ⁡ ( r , t ) ⁢ ⅆ V ∫ V ⁢ ⅆ V ) [ Equation ⁢ ⁢ 11 ] When operated with rated power, the moderator (cooling water) at an upper part of reactor core is higher in temperature and lower in density than the moderator at a lower part of the core. Therefore, burning does not more proceed at the core upper part than at the lower part. In each fuel cycle, only about one third of fuel assemblies are replaced with fresh ones, while the remaining assemblies are continuously used in the following cycle. When the reactor power is small as in the zero-power test, difference in moderator density is small between the upper and lower parts of the core, while there remains more unburned fuel at the upper part of the core. As a result, neutron flux distribution (φ) is biased to the core upper part, and hence, power distribution, which is approximately in proportion to the neutron flux distribution, is also biased to the core upper part. Accordingly, the fuel (fuel rod) temperature also varies largely at the core upper part. Specifically, at the core upper part, the neutron flux (φ) is larger and the neutron importance distribution (φT) is also higher. As a result, importance power-averaging is more highly evaluated than volume-averaged value. Therefore, we define a correction coefficient given by Equation (12), that is derived by using a one-dimensional (flow path direction) kinetic simulation code, considering space-dependency of neutron flux distribution φ(r) (including adjoint neutron flux distribution φt(r)), and fuel temperature distribution S(r) normalized as ∫rS(r)dr=1) in the coolant (moderator) flow direction. The importance power-averaged fuel temperature is obtained from the volume-averaged value by multiplying the correction coefficient cip. c ip = Δ ⁢ ⁢ T f , av ip Δ ⁢ ⁢ T f , av [ Equation ⁢ ⁢ 12 ] (Calculation of Doppler Reactivity Coefficient) Equation (13) represents the error function defined from Doppler reactivity coefficient. The Doppler reactivity coefficient αf that minimizes the error function is the measured Doppler reactivity coefficient. E rdf = 1 N ⁢ ∑ i = 1 N ⁢ { 1.0 - α f ( c ip ⁢ Δ ⁢ ⁢ T f , av ⁡ ( t i ) - Δ ⁢ ⁢ T c , av ⁡ ( t i ) ) Δ ⁢ ⁢ ρ fc ⁡ ( t i ) } 2 [ Equation ⁢ ⁢ 13 ] For evaluating the error function, values measured in a time period from reactivity addition by withdrawing control rod bank to the upper limit reactor power are used. However, the data in about 100 seconds after the withdrawal of control rod to add the initial reactivity ρin and in several tens seconds after range switching of neutron flux measurement may be omitted. In the following, inventions as recited in each of the claims will be described. The invention as recited in claim 1 provides a method of measuring Doppler reactivity coefficient, comprising: the step of measuring neutron flux in which reactor power is increased by a prescribed amount with which the temperature reactivity effect is sufficiently large to observe it clearly in reactivity transient period by applying reactivity to a reactor core, and neutron flux during this period is measured as time-series data; the step of obtaining time-series data of in-reactor average moderator temperature in which reactor power is increased by a prescribed amount by applying reactivity to a reactor core, and average moderator temperature in the reactor during this period is obtained as time-series data by a prescribed procedure; the step of obtaining time-series data of reactivity in which the time-series data of reactivity is obtained from the measured time-series data of neutron flux, using inverse kinetic method to one-point reactor kinetic equation; the step of obtaining time-series data of reactor power in which, based on said obtained time-series data of in-reactor average moderator temperature and the time-series data of neutron flux, the time-series data of reactor power matching said two time-series data with numerically evaluated time-series data by a prescribed procedure is obtained, the step of obtaining time-series data of fuel temperature in which the time-series data of fuel temperature subjected to prescribed averaging, obtained by using the time-series data of reactor power and a prescribed kinetic model; the step of obtaining reactivity feedback contribution component in which the reactivity feedback contribution component is obtained using the time-series data of reactivity and the obtained reactivity of constant reactor period; and the step of obtaining Doppler reactivity coefficient, in which the Doppler reactivity coefficient is obtained by a prescribed procedure, using the time-series data of in-reactor average moderator temperature, the time-series data of fuel temperature subjected to prescribed averaging, an isothermal temperature reactivity coefficient, and the reactivity feedback contribution component. The present invention enables measurement of Doppler reactivity coefficient of a nuclear reactor, which is easy and applicable to discontinuous data. Further, the prescribed amount of “reactor power is increased by a prescribed amount in which the reactor power is increased in a constant reactor period in a low power range and subsequently the increasing rate is gradually decreased due to temperature reactivity feedback compensation effect. The actual amount, however, is within 1% of the rated power, since the measurement is done during nuclear reactor physics test, and with this small reactor power change, the variation of various physical constants, such as heat capacities and densities of moderator and fuel affecting reactor dynamics, induced by temperature increase remain almost unchanged, i.e., constant during the measurement. Further, “time-series data” refers to data measured as the time passes from the start until a prescribed amount of power is reached. The data, however, need not be the data covering the entire period of time. Non-preferable data, for example, of about 30 seconds after range switching of neutron flux measurement and up to 100 seconds after moving the control rod bank may be excluded. As to the sampling interval, though sampling at an interval of 0.001 second is desirable considering the trade-off between accuracy of analysis and amount of data computation, it is not limiting, and analogue data is not excluded, either. Further, the “prescribed procedure” in the “step of obtaining time-series data of in-reactor average moderator temperature” refers to a procedure of obtaining an average value (result) of measurement values of temperature sensors provided at reactor outlet side cooling pipe and reactor inlet side cooling pipe, respectively, by passing the measurement values through an averaging circuit. Further, the “prescribed kinetic model” in the “step of obtaining time-series data of reactor power” refers to the commonly used one-point reactor kinetic model or core analysis code. Further, as the “fuel temperature subjected to prescribed averaging,” a value obtained based on the first-order perturbation theory or other analysis, an experimental value or the like is used. Further, the “prescribed averaging” may be, for example, “importance-averaging.” Further, the “isothermal temperature reactivity coefficient” refers to a sum of the reactivity coefficient of fuel temperature only (obtained by partial differentiation by fuel temperature) and reactivity coefficient of moderator temperature only (obtained by partial differentiation by moderator temperature). The invention as recited in claim 2 is the method of measuring Doppler reactivity coefficient described above, wherein measurement of the time-series data of neutron flux at said step of measuring neutron flux measures neutron flux as well as γ-ray; and said step of obtaining time-series data of reactivity has a removal procedure of removing influence of the γ-ray from the measured time-series data of neutron flux, and, from the time-series data with the influence of γ-ray removed, time-series data of reactivity is obtained using inverse kinetic method to the one-point reactor kinetic equation. By the invention as recited in this claim, it becomes easier to accurately measure neutron flux in a lower reactor power stage, using a simple measurement device such as an ionization chamber, in a currently operating PWR. The invention as recited in claim 3 is the method of measuring Doppler reactivity coefficient according to claim 2, wherein, in said removal procedure, (1) an error function is evaluated by the least squares method, wherein 1) the error function is defined by using a) a time-change numerically evaluated value calculated by a prescribed nuclear reactor kinetic equation using the reactivity of constant reactor period and γ-ray mixture rate as parameters related to reactor power response in a low power range in which reactivity feedback contribution is negligible, andb) a time-change part corresponding to the reactor power response of actually measured time-series data of neutron flux, and2) the error function represents difference between these two in logarithmic value; and(2) a combination of the reactivity of constant reactor period and the γ-ray mixture rate that minimizes the error function value is obtained. The γ-ray mixture rate forming the combination is regarded as true γ-ray mixture rate. In the invention according to this claim, the γ-ray mixture rate that minimizes the error function related to the difference between the numerical evaluated value and the actually measured value of reactor power closely related to the neutron flux is used and, therefore, accurate γ-ray mixture rate and hence, true reactor power, can be obtained. Here, “time-series data in a low power range in which reactivity feedback contribution is small” refers to time-series data of power within 1% of rated power, and the reason why the data in such a range is used is that the γ-ray mixture rate can be obtained accurately without necessitating correction of the influence of reactivity feedback. The invention as recited in claim 4 is the method of measuring Doppler reactivity coefficient described above, wherein at said step of obtaining in-reactor average moderator temperature, the average moderator temperature is obtained in the form of time-series data, when the reactor power is increased by a prescribed amount by applying reactivity to a reactor core in a close-to-critical state. In the invention according to this claim, process proceeds in accordance with a prescribed procedure using, for example, moderator (cooling water) temperatures at the inlet and outlet of a steam generator and the heat input from a moderator circulation pump as data for calculation, and as a result, time-series data of the moderator temperature in the reactor matched in time with the time-series data of neutron flux is obtained. Therefore, it becomes possible to determine the actual reactor power using time-series data of quantities measured in a conventional test process of the zero power reactor physics test, that is, detector current of ex-core neutron detector and the average moderator temperature. This also enables direct measurement of Doppler reactivity coefficient with standard instrumentation devices in the conventional testing procedure. It is noted that heat radiation from a coolant pipe, for example, may not be excluded for consideration “as data” mentioned above. Further, other temperature or temperatures such as inlet (low) and outlet (high) temperatures of the moderator in the reactor may be obtained. The invention as recited in claim 5 is the method of measuring Doppler reactivity coefficient described above, wherein in said prescribed procedure at said step of obtaining time-series data of reactor power, a time constant related to heat transfer from primary side to secondary side of the steam generator and an initial reactor power are selected as parameters, and a combination of said time constant and the initial reactor power that minimizes the value of the error function represented by {1−(numerically evaluated time of average moderator temperature to maximum temperature/measured time of average moderator temperature to maximum temperature)}2+{1−(numerically evaluated value of maximum change width of average moderator temperature/measured value of maximum change width of average moderator temperature)}2 is obtained. In the invention according to this claim, the combination of time constant and reactor power that minimizes the error function value is searched for, and based on the result of search, optimal time constant and upper limit reactor power are obtained. Therefore, evaluation of the in-reactor average moderator temperature according to the invention of claim 4 can be made accurate. Further, as the absolute value of upper limit power and the power variation width from the initial power to the upper limit attained power can be determined, it is possible to obtain the reactor power response represented in an absolute value from the NIS signal with γ-ray removed. Further, from the obtained reactor power response and the actually measured moderator temperature, it is possible to obtain accurate time-series data of average fuel rod temperature. The invention as recited in claim 6 is the method of measuring Doppler reactivity coefficient described above, wherein at said step of obtaining time-series data of fuel temperature, volume-averaged fuel temperature calculated by using a heat conduction equation related to average fuel rod temperature and time-series data of reactor power is modified by using a correction coefficient obtained in consideration of distributions of neutron flux and adjoint neutron flux (neutron importance) in a moderator flow path direction in zero-power state, whereby time-series data of fuel temperature subjected to prescribed averaging, based on the first-order perturbation theory, is obtained. Therefore, evaluation of fuel temperature becomes accurate. The invention as recited in claim 7 is the method of measuring Doppler reactivity coefficient described above, wherein said prescribed averaging is importance power averaging, and in the prescribed procedure at said step of obtaining Doppler reactivity coefficient, the following equation is used: “reactivity feedback contribution component related to Doppler reactivity coefficient=Doppler reactivity coefficient×(change amount of fuel temperature obtained by using time-series data of importance power-averaged fuel amount of average in-reactor moderator temperature)+isothermal temperature reactivity coefficient×change amount of average in-reactor moderator temperature.” In the invention according to this claim, since an accurate equation is used, an accurate estimation of Doppler reactivity coefficient can be made. Here, “importance power averaging” refers to weight average by neutron importance distribution and neutron flux distribution, assuming that reactivity changes with fuel temperature variation based on the first perturbation theory. The invention as recited in claim 8 is the method of measuring Doppler reactivity coefficient described above, wherein further in the prescribed procedure at said step of obtaining Doppler reactivity coefficient, a Doppler reactivity coefficient is selected as a parameter, and a Doppler reactivity coefficient that minimizes the value of an error function is estimated as the actual Doppler reactivity coefficient, wherein the error function is defined as {1.0−Doppler reactivity coefficient×(change amount of fuel temperature obtained by using time-series data of importance power-averaged fuel amount of average in-reactor moderator temperature)/reactivity contribution component related to Doppler reactivity coefficient}2 based on the obtained data. In the invention according to this claim, Doppler reactivity coefficient is used as a parameter and the Doppler reactivity coefficient that minimizes the error function is obtained. Therefore, thus obtained Doppler reactivity coefficient has high accuracy. The present invention enables measurement of Doppler reactivity coefficient of a nuclear reactor which is easy and applicable to discontinuous data. 10reactor core11ionization chamber12ionization chamber20steam generator21temperature sensor22temperature sensor30cooling water circulation pump31ampere meter41nuclear reactor outlet side pipe42nuclear reactor inlet side pipe50minute electric current meter51DC amplifier52terminal base53A/D converter board (note PC) In the following, the present invention will be described based on a best mode thereof. It is noted that the present invention is not limited to the embodiment below. Various modifications may be made on the following embodiment, within the same and equivalent scope of the present invention. In the present embodiment, data obtained by actual measurement of existing PWR are processed, to measure the Doppler reactivity coefficient of the nuclear reactor. (Analysis System) The reactor core characteristics are analyzed using one-point reactor kinetic simulation model and one-dimensional (in the direction of cooling water flow) kinetic simulation model and, for the analysis, radial power distribution of reactor core is assumed to be flat, as fuel assemblies are loaded so as to be flat distribution. (Measurement System) FIG. 2 schematically shows the measurement system including device configurations in accordance with the present embodiment. Referring to FIG. 2, Reference Characters 11 and 12 denote ionization chambers for ex-core neutron flux detection; 21 and 22 temperature sensors such as resistance temperature detector (RTD); 31 a current meter; 50 a minute ampere meter; 51 a DC amplifier; 52 a terminal base; and 53 an A/D conversion board (note PC). Dotted lines represent signal lines for measurement. The AD converter had the resolution of −10 to +10V/16 bit. Data sampling time interval was 0.001 second and the time of measurement was 2600 seconds. In addition to the above, a low-pass filter, an amplifier and the like are also used. (Selection of Measurement Data) Up to 100 seconds after movement of the control rod bank, spatial variation in power distribution occurs because of the movement of control rods, which has influence on the NIS signal. Therefore, response in the time domain having such influence is excluded from the object of fitting (analysis). As the reactor power is increased from an initial power state up to about 200 times, the measurement range of NIS (number of figures as the object of measurement) must be switched. The measurement is influenced for about 30 seconds after the switching and, therefore, this time period is excluded from the object of fitting. Data before the peak at which the upper limit value is recognized, where operational environment of steam generator secondary system is considered relatively stable, were used. (Measured Time-Series Data) Control rods were operated so that the PWR, which was initially sub-critical, achieved critical and the power was further increased until a sufficiently large temperature reactivity compensation effect is observed in reactor transient, while the neutron flux and moderator temperature were measured. FIG. 3 shows time-series data of neutron flux obtained by actual measurement. In FIG. 3, the ordinate represents neutron flux converted to current (A), and the abscissa represents time passed from the start of data acquisition. In graphs showing time-series data of physical amounts discussed later, the ordinate represents physical amount and the abscissa represents time passed from the start of data acquisition, as above. FIG. 4 also shows time-series data of average moderator temperature. As compared with FIG. 3, it can be seen that there is a delay of about 50 seconds between the maximum value peaks. It was found from theoretical analysis that the time delay results from heat removing characteristics of steam generator, which is dominantly influenced by a time constant τsg,12 related to heat transfer (heat transmission) from the primary side to the secondary side of the steam generator, and that the larger the constant τsg,12, the larger the delay. Further, τsg,12 was found to be about 34 seconds. (Removal of γ-Ray) From the obtained neutron flux data, numerical values of γ-ray mixture rate gc=0.78 and reactivity of constant reactor period ρp=46.6 pcm were calculated from the least squares fitting using Equation (1). FIG. 5 shows time-series data of power calculated from Equation (2) using the calculated γ-ray mixture rate gc. In FIG. 5, the ordinate represents the ratio of reactor power P to rated power, the solid line represents time-series data of reactor power P obtained based on the neutron flux after γ-ray removal, and the dotted line represents time-series data of reactor power obtained based on the neutron flux before γ-ray removal. It is noted that the dotted line is basically the same as the data of FIG. 3 represented in detector current value. It can be seen from FIG. 5 that in a range where reactor power P is small, the influence of γ-ray appears significantly. Further, the width of reactor power variation was about 220 times. Two reactivity feedback contribution components calculated from Equations (4) and (6) corresponding to the time-series data of reactor power P shown in FIG. 5 are shown. Around 600 to 800 seconds of FIG. 6, the upper line shows the feedback contribution component Δρfc related to Doppler reactivity coefficient, and the lower line shows the overall reactivity feedback effect, Δρin, induced by Doppler and moderator reactivity feedback. (Determination of Upper Limit Attained Reactor Power) By the method described in the section of (Primary Cooling Loop Heat Removal Model) above applied to the model shown in FIG. 1 as an object, it was found that τsg,12=34 s, and P0=3.77×10−4%/rated power, and hence upper limit reactor power Pmax=8.35×10−2%/rated power. Further, time-series data of average moderator temperature ΔTc,av numerically evaluated using reactor kinetics simulation model using these values was obtained as shown in FIG. 7. In FIG. 7, the solid line represents the calculated value, and the dotted line is the measured value. In the response before the peak time as the object of fitting, no difference is recognized between the measured value and the calculated value including the peak time and the peak value. (Calculation of Average Fuel Temperature) From the neutron flux distribution and neutron importance distribution calculated evaluated with one-dimensional (flow path direction) kinetics simulation model, the correction coefficient value cip for converting the volume-averaged fuel temperature to importance-averaged fuel temperature was calculated using Equation (12), of which result was 1.296. Though high-speed group neutron flux was used as the Doppler reactivity feedback effect is of interest, the results were not different when thermal neutrons were used. Further, using this value, importance-averaged fuel temperature was calculated. (Estimation of Doppler Reactivity Coefficient) From Equation (13), Doppler reactivity coefficient αf that minimizes the error function was estimated, and the result was αf=−3.2 [pcm/K], which was the same as the design value to two significant figures.
	description	The present invention relates to the field of radioactive substances and in particular to handling of radioactive solutions. Provided by the present invention is a device that enables preparation of capsules filled with radioactivity. More particularly, the capsules filled with radioactivity are suitable for oral administration for use in certain radiopharmaceutical procedures. Radiopharmaceuticals are administered to patients either orally or by intravenous injection. One method for oral administration is via a small capsule that contains a diagnostic or therapeutic dose of the radioactive isotope. These capsules are routinely prepared in nuclear pharmacies by manually injecting a solution containing the radioactive isotope into the capsules, typically made from hard gelatin. In a known process, one large gelatin capsule and one small gelatin capsule are used for each dose prepared. Each large capsule comprises two parts and is empty, and each small capsule may contain an absorbing buffer such as Dibasic Sodium Phosphate Anhydrous USP. The required volume of a radioactive solution to produce the necessary dose in MBq or mCi is calculated based on the calibration date and radionuclidic concentration. The large capsule is pulled apart and the small capsule is placed into the bottom half of the large capsule. The volume of radioactive solution is withdrawn using a shielded syringe and then injected into the top centre of the small capsule. Then the upper part of the large capsule is secured around the bottom half so that the small capsule is contained within the large capsule. Following measurement of the patient dose in a suitable radioactivity calibration system the dose is administered to a patient. This known filling process of capsules is manual and therefore subject to variation between individual operators. This is problematic for accuracy and uniformity of the patient doses inside the capsule. Furthermore, although shielding is mostly used around the syringe in this manual process, no shielding is provided around the capsule itself thereby giving a high radiation burden to the hands of the operator. In addition, this manual process is prone to spills and needle stick injuries. It would therefore be desirable to have better accuracy and uniformity of patient doses, reduced radiation burden and reduced possibility of a spill or needle stick injury. In a first aspect the present invention provides a system (1) comprising: (i) a capsule holder (2) having a lower end (2a) and an upper end (2b) wherein said capsule holder comprises a solid base (2c) positioned at said lower end (2a), a solid body (2d) extending upwardly from said solid base (2c), and a well (2e) extending downwardly within said solid body (2d) wherein said well (2e) opens at the upper end (2b) of said capsule holder (2) and ends prior to said solid base (2c) and is configured to receive a lower half (3a) of a capsule (3), wherein said capsule holder (2) is formed from a radiation-shielding material; (ii) a shielded needle positioner (4) having a lower end (4a) and an upper end (4b) wherein said shielded needle positioner (4) comprises a solid body (4c) defining a bore (4d) extending substantially linearly and centrally therethrough, said bore (4d) comprising a lower section (4e) opening onto said lower end (4a) and configured to be fitted over and contain the solid body (2d) of said capsule holder (2), and an upper section (4f) opening onto said upper end (4b) and configured to receive an upper half (3b) of a capsule (3), wherein said shielded needle positioner (4) is formed from a radiation-shielding material. In a second aspect the present invention provides a method for filling a capsule (3) with radioactivity wherein said capsule comprises an inner shell (3c) and an outer shell (3d) wherein said outer shell (3d) comprises a lower diameter body (3e) and a greater diameter cap (3f) and wherein said method comprises the following steps: (a) providing the system of the invention as defined herein; (b) placing said lower diameter body (3e) into the well (2e) of the capsule holder (2); (c) placing said inner shell (3c) into said lower diameter body (3e); (d) placing the shielded needle positioner (4) over the capsule holder (2) containing the lower diameter body (3e) and the inner shell (3c) so that the solid body (2d) of the capsule holder (2) is contained within the lower section (4e) of the bore (4d) of the shielded needle positioner (4) and an upper half of the inner shell (3c) is contained within the upper section (4f) of the bore (4d) of the shielded needle positioner (4); (e) introducing a first needle (7a) attached to a shielded syringe (7) containing a solution of radioactivity into the upper section (4f) of the bore (4d) at the upper end (4b) of said shielded needle positioner (4); (f) injecting the solution of radioactivity into the inner shell (3c) (g) removing the shielded needle positioner (4); (h) fixing said greater diameter cap (3f) to said lower diameter body (3e) so that said inner shell (3c) is securely contained within said outer shell. The present invention provides improved accuracy and uniformity of patient doses. Furthermore, the potential for spills and needle stick injuries is reduced and the radiation burden is reduced. The invention makes filling of oral capsules with a radioactive solution safe and easy. It offers protection from radiation through shielding all around the filling process. It also ensures correct placement of the syringe and needle every time, resulting in an accurate and uniform patient dose inside the capsule. Furthermore, the inventive system allows the operator to fill the capsules faster, which also reduces the radiation burden for the operator. The system and method of the invention are of relevance to all sites where oral capsules need to be filled with radioactive solution or another hazardous solution. In the USA there are in excess of 400 nuclear pharmacies that prepare such oral capsules that could benefit from using the present invention. The terms “comprising” or “comprises” have their conventional meaning throughout this application and imply that the agent or composition must have the essential features or components listed, but that others may be present in addition. The term ‘comprising’ includes as a preferred subset “consisting essentially of” which means that the composition has the components listed without other features or components being present. The term “capsule” as used herein is intended to refer to a pharmaceutical preparation comprising a hard or soft shell typically containing a single dose of active substance. In one embodiment said capsule is intended for oral administration. Such capsules are well known to those of skill in the art and are described in the US and European Pharmacopeias. The shell of the capsule may be made from a biodegradable material, for example gelatin, starch or other similar substances, which upon attack by digestive fluids allows the contents to be released. The consistency of the shell material may be adjusted by the addition of substances such as glycerol or sorbitol. Excipients such as surface-active agents, opaque fillers, antimicrobial preservatives, sweeteners, colouring matter authorised by the competent authority and flavouring substances may be added. The capsules may bear surface markings. Hard-shell capsules for human use come in a range of sizes from No. 5, the smallest, to No. 000, which is the largest. Size No. 00 is generally is the largest size acceptable to patients (see e.g. Chapter 6 “Pharmaceutical Calculations” 2016 Jones and Bartlett Learning; Payal Agarwal, Ed.). In certain embodiments the capsules include contents of a solid, liquid or paste-like consistency comprising one or more active substances with or without excipients such as solvents, diluents, lubricants, disintegrating agents, reducing agents, pH-adjusting agents and stabilizers. Suitably, the contents should not cause deterioration of the shell and the shell should be sealed appropriately to prevent any leakage. For the absorption and retention of a quantity of a radioactive solution, the small capsule may contain a hydroscopic crystalline powder. 123I capsules are well-known in the art (see e.g. Chapter 34 “Iodine Chemistry and Applications” 2015 John Wiley & Sons; Tatsuo Kaiho, Ed.) The term “solid” is used herein in connection with various components of the system of the invention and takes its ordinary meaning, i.e. firm and stable in shape. The terms “upper” and “lower” are used herein in connection with various components of the system of the invention and describe said components when positioned in a typical manner within the system of the invention, for example as illustrated in the non-limiting embodiment of FIG. 1. The terms “extending upwardly” and “extending downwardly” take their ordinary meaning, i.e. towards a higher place and towards a lower place, respectively. The term “well” refers to a depression or enclosed space designed to provide sufficient space to accommodate and orientate a capsule therein. The term “radiation-shielding material” refers to any one of various high atomic number (Z) materials that absorb radiation and can be used as protection for radiation. For alpha particles where the range is very short, a very thin layer of material is sufficient. For beta particles the shielding is ideally first a layer with a material with a low atomic number, e.g. followed with a second layer of a material with a high atomic number. Gamma radiation on the other hand has is highly penetrative and therefore a highly absorbing material should be used. For economic reasons, lead (Pb) is the most commonly used for this purpose. Another material that is frequently used is tungsten (W). Tungsten has the advantage that it is a robust material, unlike lead which is relatively soft. The reader is referred for more detail to Saha G B “Physics and Radiobiology of Nuclear Medicine” (New York: Springer; 2001. p. 218). In one embodiment of the system (1) of the invention said shielded needle positioner (4) further comprises a cap (4g) configured to fit over the upper end (4b) thereof wherein said cap comprises a bore (4h) therethrough having a similar width to the upper section (4f) of the bore (4d) of the shielded needle positioner (4), wherein said cap (4g) is formed from a radiation-shielding material. In one embodiment of the system (1) of the invention said radiation-shielding material is comprises lead, steel or tungsten. In one embodiment the system (1) of the invention further comprises: (iii) a preliminary needle positioner (6) having a lower end (6a) and an upper end (6b) wherein said preliminary needle positioner (6) comprises a body (6c) defining a bore (6d) extending substantially linearly and centrally therethrough, said bore (6d) comprising a lower section (6e) opening onto said lower end (6a) and configured to be fitted over and contain the solid body (2d) of said capsule holder (2), and an upper section (6f) opening onto said upper end (6b) and configured to contain an upper half (3b) of a capsule (3), wherein said shielded needle positioner (6) is formed from a rigid material. With this embodiment it is possible to vent the inner capsule with a larger bore needle first and also provide a target for injection of a solution of radioactivity thereafter. The diameter of the needle is indicated by the needle gauge. Various needle lengths are available for any given gauge. There are a number of systems for gauging needles, including the Stubs Needle Gauge and the French Catheter Scale. Smaller gauge numbers indicate larger outer diameters. Needles in common medical use range from 7 gauge (the largest) to 33 (the smallest) on the Stubs scale. An list with gauge comparison chart can e.g. be found at the following link: https://en.wikipedia.org/wiki/Needle_gauge_comparison_chart. An International Standard is available to establishes a colour code for the identification of Single-use hypodermic needles of nominal outside diameters (ISO 7864:1993 Sterile hypodermic needles for single use). In one embodiment of the system (1) of the invention each of the components is substantially cylindrical. In one embodiment of the system (1) of the invention said rigid material comprises a rigid plastic. A suitable plastic is one that is readily available and that can be easily crafted, e.g. by injection moulding or machining, without need to use difficult tools. In one embodiment said rigid material is transparent but this is not essential. In one embodiment of the system (1) of the invention said rigid material comprises Perspex. In one embodiment of the system (1) of the invention said rigid material comprises a metal. In one embodiment of the system (1) of the invention said body (6c) of said preliminary needle positioner (6) is solid. In one embodiment of the system (1) of the invention said body (6c) of said preliminary needle positioner (6) is a scaffold. In one embodiment the system (1) of the invention further comprises securing means (6g) configured to support a needle within the bore (6d) of said preliminary needle positioner (6). In one embodiment of the system (1) of the invention said securing means (6g) comprises a spring or a screw. Suitable examples of securing means will be evident to those of skill in the art, e.g. stainless steel springs or screws. The function is to fix the syringe in place for puncturing multiple capsules. In one embodiment of the method of the invention steps (a)-(h) are carried out sequentially. In one embodiment of the method of the invention said capsule (3) is suitable for oral administration. In one embodiment of the method of the invention said capsule (3) is made from a material comprising gelatine or polymer formulated from cellulose. In one embodiment of the method of the invention said capsule (3) is made from hard gelatine. In one embodiment of the method of the invention said inner shell (3c) contains an absorbing buffer. In one embodiment of the method of the invention said absorbing buffer comprises a hydroscopic crystalline powder. In one embodiment of the method of the invention said absorbing buffer is dibasic sodium phosphate anhydrous USP. In a particular embodiment said absorbing buffer is around 200-500 mg dibasic sodium phosphate anhydrous USP. In one embodiment of the method of the invention said inner shell (3c) contains a stabiliser. In one embodiment of the method of the invention said stabiliser is disodium edetate dehydrate. In one embodiment of the method of the invention said inner shell (3c) contains a reducing agent. In one embodiment of the method of the invention said reducing agent is sodium thiosulfate pentahydrate. In one embodiment of the method of the invention, at the end of said method, the pH of the contents of said inner shell (3c) is in the range 7.5-9.0. In one embodiment of the method of the invention said solution of radioactivity comprises a radioactive isotope suitable for use as an orally-administered radiopharmaceutical. The list below provides non-limiting examples of radiopharmaceuticals that are suitable for oral administration in a capsule and therefore for the present invention. Radiopharma-ceuticalRangeReferenceI-123 Sodium3.7 MBq-14.8Summary of Product CharacteristicsIodide:MBq(SPC)I-131 Sodium0.2-11 MBqSummary of Product CharacteristicsIodide:diagnostic(SPC)indications200-11100 MBqtherapeuticindicationsTc-99m 2-925 MBqSummary of Product Characteristicspertechnetate(SPC) of Drytec ®I-124 Sodium0.2-74 MBqFreudenberg L S, Jentzen W, PetrichIodideT, Frömke C, Marlowe R J, HeusnerT, Brandau W, Knapp W H,Bockisch A. Lesion dose indifferentiated thyroid carcinomametastases after rhTSH or thyroidhormone withdrawal: 124IPET/CT dosimetric comparisons. EurJ Nucl Med Mol Imaging. 2010December; 37(12): 2267-76. PMID:20661558.Freudenberg L S, Jentzen W, StahlA, Bockisch A, Rosenbaum-KrummeS J. Clinical applications of 124I-PET/CT in patients with differentiatedthyroid cancer. Eur J Nucl Med MolImaging. 2011 May; 38 Suppl 1: S48-56. PMID: 21484380.Jentzen W, Freudenberg L, Eising EG, Sonnenschein W, Knust J,Bockisch A. Optimized 124I PETdosimetry protocol for radio-iodinetherapy of differentiated thyroidcancer. J Nucl Med. 2008 June;49(6): 1017-23. PMID: 18483099. However, for each individual case, the dose prescribed must be determined by the attending specialist. In an individual case the attending specialist might choose to use a activity/dose different than mentioned in the table above. This will be known to the person of skill in the art, for example as described for 131I at the following link: http://reference.medscape.com/drug/hicon-sodium-iodide-i-131-999924. In one embodiment of the method of the invention said radioactive isotope is radioiodine or 99mTc. In one embodiment of the method of the invention said radioiodine is selected from the group comprising 123I, 131I and 124I. Non-limiting examples of typical doses of 123I, 131I and 124I are 3.7 MBq, 1000 MBq and 74 MBq, respectively. In one embodiment of the method of the invention said solution of radioactivity is a solution of sodium iodide. In one embodiment of the method of the invention said solution of radioactivity is a solution of 99mTc pertechnetate. In one embodiment of the method of the invention said method includes the further steps carried out in between steps (c) and (d) of: (c-i) placing the preliminary needle positioner (6) as defined herein over the capsule holder (2); (c-ii) introducing a second needle (7b) into the upper section (6f) of the bore (6d) at the upper end (6b) of said preliminary needle positioner (6) wherein said second needle (7b) has a smaller gauge compared to said first needle (7a); (c-iii) optionally securing said second needle (7b) into place in said needle positioner; (c-iv) piercing a hole in the top of the inner shell (3c) with said second needle (7b); and, (c-v) removing the preliminary needle positioner (6). In one embodiment of the method of the invention said securing step (c-iii) is achieved by means of securing means (6g) supported within said preliminary needle positioner (6). In one embodiment of the method of the invention said securing means (6g) comprises a screw or a spring. In one embodiment the method of the invention is automated. The system of the invention comprises components of regular shape and size and the method is easily definable in time and space. As such, a person of skill in the art would have no difficulty in automating the system and method of the present invention. Automation of the method of the present invention would be convenient in a radiopharmacy filling in the region of up to 10 oral capsules per day. This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. To more clearly and concisely describe and point out the subject matter of the claimed invention, definitions are provided herein for specific terms used throughout the present specification and claims. Any exemplification of specific terms herein should be considered as a non-limiting example. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. All patents and patent applications mentioned in the text are hereby incorporated by reference in their entireties, as if they were individually incorporated. Introduction: A study was performed to compare the known manual method with the method using an exemplary system of the invention. 10 capsules were filled with a solution of Tc-99m pertechnetate (obtained from a Drytec® generator) using the manual technique and 10 capsules were filled using an exemplary method of the invention. The time required for the actual filling process of the capsule was recorded. After the capsules were filled the activity of each capsule was measured in a dose calibrator (Veenstra). Results: The method with the method of the invention was for the actual filling process faster. The results are summarized in the table below. The method with the method of the invention proved to be twice as fast as manual filling. Time to fill 10 capsules manual and with the present inventionManualInventionDifferenceTime for filling (s)23.62 ± 08.3710.26 ± 03:9113.36 fasterValues represent time in seconds (mean ± SD);n = 10 The uniformity of the capsules was determined by measuring the activity (the patient dose) per capsule. The results are plotted in FIG. 8 (wherein the exemplary system of the invention is referred to as “Capsule Filling Shield”) and summarized in the table below. Using USP guidelines <905> it was shown that for 10 capsules the manual method did not pass the criteria mentioned in USP for 10 units. The method of the invention in contrast did meet these requirements. Uniformity of content for manual methodand with the present inventionManualWith CFSActivity74.41 ± 6.3474.13 ± 3:68All activities within ≥85%NoYesand ≤115% range & RSD <6%Values represent activity in MBq (mean ± SD);n = 10Conclusion: It was shown that the method of the invention made the filling process of the capsules twice as fast. Operators also reported reduced chances of spills or needle stick injuries. Regarding the uniformity of the capsules it was shown that the method of the invention produced capsules meeting the USP guidelines. The inventive method gave a better uniformity of the capsules compared with the known manual method. Introduction: A calculation was done to show the effect on extremity radiation exposure. The calculation was done for three Iodine isotopes, as these isotopes are mostly used for compounding capsules in nuclear pharmacies. The three Iodine isotopes chosen were: I-123, I-124 and I-131. In the calculation activity of 3.7 MBq for I-123, 74 MBq for I-124 and 1000 MBq for I-131 are chosen. These represent normal patient doses. Results: The radiation exposure of the hands was calculated for the manual method and the exemplary method of the invention. The results are mentioned in the tables below and plotted in FIG. 9 (the invention referred to in FIG. 9 as “CFS”, which stands for capsule filling shield). Dose RateDistanceConstantRadiationManualtoTime(μSv/hShieldingHalflayerexposureActivitysourceto fill per(cmvaluefor handsNuclide(MBq)(cm)(s)MBq/m2)Tungsten)(cm)(μSv)I-1233.71023.620.04600.10.11I-124741023.620.1700.58.25I-13110001023.620.06600.243.30 Dose RateDistanceConstantRadiationInventiontoTime(micro Sv/hShieldingHalflayerexposureActivitysourceto per(cmvaluefor handsNuclide(MBq)(cm)fillMBq/m2)Tungsten)(cm)(μSv)I-1233.71010.740.0461.50.11.55E10−6I-124741010.740.171.50.50.47I-13110001010.740.0661.50.20.11Conclusion: The radiation exposure to hands was calculated for two methods of filling of capsules. Faster filling and extra shielding with the method of the present invention contributed to a considerable decrease in radiation exposure to the hands. For I-123 the radiation exposure was reduced to almost zero. For I-131 the radiations exposure was reduced a factor 394. For I-124 the radiations exposure was reduces a factor 17.5. The present invention therefore proves to reduce radiation burden on hands.
	summary
050777742	abstract	A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.
	summary
	abstract	An apparatus and method for maintaining contact between a pod of transducers and an inner surface of a reactor pressure vessel filled with water of a nuclear power plant is described. An underwater carriage carries the pod of transducers each of which is independently movable and are constantly urged against the surface of the vessel during inspection. Each transducer is independently pivotable about two axes. Each transducer emits and receives signals to detect any flaws of potential problems in the reactor pressure vessel.
059498390	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 and 2 show a boiling-water fuel assembly 1 according to the prior art which comprises a long tubular container, with a rectangular cross section, referred to as a fuel channel 2. The fuel channel 2 is open at both ends so as to form a continuous flow passage, through which coolant flows. The fuel channel 2 is provided with a hollow support means 3 of cruciform cross section, which is secured to the four walls of the fuel channel. The support means comprises four hollow wings 3a and a hollow enlarged cruciform center 3b. The support means forms a vertical water channel 4 through which non-boiling water flows upwardly through the fuel assembly. The fuel channel with support means surround four vertical channel-formed parts 5a-5d, so-called sub-channels, with a substantially square cross section. Each sub-channel contains a sub-bundle comprising a plurality of fuel rods 6 arranged in parallel, which contain fuel in the form of a number of cylindrical pellets 7 of uranium dioxide stacked on top of each other and enclosed in a cladding tube 8. The upper part of the fuel rod is sealed by a top plug 9 and its lower part by a bottom plug 10. The active part of the fuel assembly consists of that part which contains fuel and its height is determined by the height of the stacks of pellets. The fission gas plenum 11 is arranged between the stack of pellets and the top plug 9. The fission gas plenum should correspond to 5-10% of the volume of the fuel. For a fuel rod whose diameter is substantially constant and whose active length is 4 meters, this means that the fission gas plenum should be 0.2-0.4 meters. A helical spring 12 is arranged in the fission gas plenum and the task thereof is to absorb movements in the pellets as well as to press down the stack of pellets against the bottom plug. The fuel rods 6 are kept spaced-apart by means of spacers 13 and are prevented from bending or vibrating when the reactor is in operation. The upper ends of the fuel rods are retained by a top tie plate 14 and their lower ends are retained by a bottom tie plate 15. Through two openings in the top tie plate 14, there extend two supporting fuel rods 6a which partially extend above the top tie plate. The two supporting fuel rods 6a are fixed to the bottom tie plate 15 and are each provided with a nut 16 at the upper side of the top tie plate 14. In this way, the top tie plate is prevented from being lifted out of its position by the water flowing through the fuel assembly. The other fuel rods in the sub-bundle are arranged resting on the bottom tie plate 15 and guided therein by pins on the bottom plugs 10 of the rods. The fuel rods make contact with the lower side of the top tie plate 14 by means of a helical spring 17 arranged around the respective top plugs 9 of the fuel rods. The helical springs 17 press the top tie plate 14 against the nuts 16, whereby these nuts limit the maximum distance between the top and bottom tie plates. The spaces between the fuel rods within each sub-channel are traversed by coolant. At the top of the fuel assembly, there is a top piece 18 provided with a handle in which the fuel assembly can be lifted. FIG. 3 shows a fuel assembly which, during operation, has a considerably lower pressure drop in its upper part as compared with the prior art. To avoid problems with turbulence, the reduction of the pressure drop occurs by allowing the coolant to expand successively in a number of steps. In a first step, the expansion takes place by part of the coolant, when reaching the end of the active part, flowing into the water channel 4 through a number of openings 20 and being conducted past the uppermost spacer 21. These openings 20 are arranged immediately below the level L--L where the active part ends. Above the level L--L there is thus no fuel. The openings 20 should not be arranged too far below this level since steam in the water channel deteriorates the moderation of the fuel. In a second step, the coolant expands due to the fuel rods 22 changing to a smaller diameter. The transition takes places immediately above the active part. The upper narrower part comprises a fission gas plenum and will be referred to in the following as a plenum part. The plenum part comprises a plenum tube 23 and a top plug 24. The upper part of the fuel rods are retained and supported by a top spacer 21 instead of by a top tie plate. The top spacer 21 is arranged immediately above the transition between the larger diameter of the cladding tube 8b and the smaller diameter of the plenum part. The plenum tubes 23 run freely through the top spacer 21 and extend about 10-20 cm above the top spacer. A spacer contains less material than a top tie plate and the top spacer which surrounds the plenum part can thus provide a smaller pressure drop than a top tie plate. The top spacer 21 comprises cells, for mutually fixing the fuel rods, which have an inside diameter corresponding to the outside diameter of the plenum tubes 23. The other spacers 13 comprise cells which have an inside diameter corresponding to the outside diameter of the cladding tubes 8b. The top spacer rests partly against the fuel channel 2 and partly against the support means 3. The fuel rods 22 are prevented from moving upwardly past the top spacer 21 since this surrounds the plenum tubes 23 which have a smaller diameter than the cladding tube 8b. In each sub-bundle there are two so-called supporting fuel rods (not shown), which have the same thickness along their whole length. These are intended to lift the sub-bundle out of the fuel assembly. In their upper ends, the supporting fuel rods fix the top spacer and in their lower ends they are fixed to the bottom tie plate. In a third step, expansion takes place due to the fact that the upper edge of the support means 3 terminates immediately above the top spacer 21 and somewhat below the upper part of the fuel rods. The support means as such causes a certain pressure drop. By terminating the support means further down in the fuel assembly, the pressure drop is reduced. Between the support means and the top piece, there is an interconnecting member 25 which distributes the lifting force so that the fuel channel 2 need not carry the whole lifting force when the fuel assembly is to be lifted. The connection between the fuel channel 2 and the top piece 18 may thus be given an advantageous design from the point of view of pressure drop. In a fourth step, a smooth expansion takes place at the end of the fuel rods. The top plug 24 is designed so that the transition may be as smooth as possible. At the top plug, a further reduction of the diameter occurs. The top plug 24 comprises a cylindrical pin 26 which has a diameter which is smaller than the diameter of the plenum tube 23 and which is arranged above the plenum tube. The final expansion occurs when the coolant leaves the fuel assembly via the top piece 18. FIG. 4a shows in more detail the composition of a fuel rod 22 intended for a fuel assembly according to the invention. In its lower part the fuel rod comprises a stack of fuel pellets 7 surrounded by a cladding tube 8b. Above the pellets there is a space 27 in which the pellets are allowed to expand. The height of the space 27 is about 10 cm. In the space 27 there is a short helical spring 28 adapted for locking during transport of the fuel. The upper end of the helical spring rests against the transition to the plenum tube 23 and its lower end presses against the stack of pellets. Above, and partly inserted into, the cladding tube, the plenum tube 23 is arranged. In the example, the plenum tube 23 has an outside diameter corresponding to the inside diameter of the cladding tube 8b. The plenum tube is hollow and sealed by a top plug 24 at its upper end. The top plug extends somewhat above the plenum tube and comprises a cylindrical pin 26 with a diameter which is smaller than the diameter of the plenum tube 23. The pin is intended to be engaged by means of a chucking tool. The plenum tube surrounds a space 29 which, together with the space 27, constitutes the fission gas plenum. The transition between the cladding tube and the plenum tube is open so that the fission gases which are formed in the fuel pellets may pass into the space 29. Since it is sufficient to use a short helical spring 28, the whole space 29 becomes available for fission gases. Only a small increase in length of the fuel rod is therefore needed to compensate for the smaller diameter. FIG. 4b shows an embodiment of a fuel rod for a fuel assembly according to the invention which differs from the fuel rod in FIG. 4a by the provision of a hollow intermediate piece 30 between the cladding tube 8b and the plenum tube 23. In its upper part, the top plug 24 has the shape of a sphere to facilitate lifting the top plug. FIG. 4c shows an additional embodiment of a fuel rod for a fuel assembly according to the invention where the plenum tube 23 and the top plug 24 form an integral unit.
	abstract	The invention relates to a diaphragm unit 4 or a diaphragm unit 4 and an associated x-ray emitter 1 with adjustment option for displaying an asymmetrical area under examination, with the diaphragm unit 4 being able to be tilted in accordance with the invention relative to the x-ray emitter 1, preferably by moving it on a rail system 12 attached isocentrically to the tube focus 9 on the tube housing 2 and/or the unit 1;4 made up of diaphragm unit 4 and x-ray emitter 1 being able to be tilted isocentrically to the tube focus 9 of the x-ray tube 2.
	claims	1. A method comprising:depressurizing a nuclear reactor that includes at least:a pressure vessel including an upper vessel section and a lower vessel section connected by a mid-flange and containing primary coolant,a nuclear reactor core disposed in the lower vessel section and immersed in the primary coolant, andupper internals suspended from the mid-flange of the pressure vessel and disposed below the mid-flange, the upper internals including at least internal control rod drive mechanisms (CRDMs) with CRDM motors immersed in the primary coolant and control rod guide frames disposed between the CRDM motors and the nuclear reactor core;disconnecting and removing the upper vessel section from the remainder of the pressure vessel while leaving the mid-flange in place on the lower vessel section with the upper internals remaining suspended from and disposed below the mid-flange;removing the mid-flange from the lower vessel section with the upper internals remaining suspended from the mid-flange and disposed in the lower vessel section;replacing fuel of the nuclear reactor core;placing the mid-flange back onto the lower vessel section with the upper internals remaining suspended from the mid-flange; andplacing the upper vessel section back onto the remainder of the pressure vessel and re-connecting the upper vessel section with the remainder of the pressure vessel,wherein the nuclear reactor further includes a central riser disposed in the upper vessel section and riser cone connecting the central riser with the lower vessel section, the riser cone remaining disposed with the remainder of the pressure vessel upon completion of the disconnecting and removing of the upper vessel section, and the method further comprises:removing the riser cone prior to removing the mid-flange from the lower vessel section with the upper internals remaining suspended from the mid-flange. 2. The method of claim 1 wherein the disconnecting comprises disconnecting fasteners that extend through a flange assembly including the mid-flange, a flange on the upper vessel section, and a flange on the lower vessel section. 3. The method of claim 2 wherein the disconnecting also disconnects the upper vessel section from the remainder of the pressure vessel and disconnects the mid-flange from the lower vessel section, the disconnecting and removing of the upper vessel section leaving the mid-flange in place on the lower vessel section due to weight of the mid-flange and the upper internals that remain suspended from the mid-flange. 4. The method of claim 2 wherein the fasteners include bolts that remain in a parked position at least partially inserted into the flange on the upper vessel section after completion of the disconnecting and removing of the upper vessel section. 5. The method of claim 2 wherein the fasteners include bolts that remain in a parked position at least partially inserted into one of (1) the flange on the upper vessel section and (2) the flange on the lower vessel section after completion of the disconnecting and removing of the upper vessel section. 6. The method of claim 1 wherein the nuclear reactor further includes a steam generator disposed inside and secured with the upper vessel section, and the steam generator remains disposed inside and secured with the upper vessel section during and upon completion of the disconnecting and removing of the upper vessel section. 7. The method of claim 1 wherein the mid-flange includes electrical connections through the mid-flange to the upper internals, and the method further comprises:prior to the removing of the mid-flange, disconnecting cables external to the pressure vessel from the connections through the mid-flange to the upper internals. 8. The method of claim 7 wherein cables internal to the pressure vessel running from the connections through the mid-flange to the upper internals are left in place during the removing of the mid-flange. 9. A method comprising:depressurizing a nuclear reactor that includes at least:a pressure vessel including an upper vessel section and a lower vessel section connected by a flange assembly and containing primary coolant wherein the flange assembly includes at least a flange on the upper vessel section and a flange on the lower vessel section,a nuclear reactor core disposed in the lower vessel section and immersed in the primary coolant,a mid-flange supported by the lower vessel section, andupper internals suspended from the mid-flange of the pressure vessel and disposed below the mid-flange, the upper internals including at least internal control rod drive mechanisms (CRDMs) with CRDM motors immersed in the primary coolant and control rod guide frames disposed between the CRDM motors and the nuclear reactor core;disconnecting the upper vessel section from the lower vessel section and lifting the upper vessel section away from the lower vessel section with the mid-flange remaining supported by the lower vessel section and the upper internals remaining suspended from and disposed below the mid-flange;lifting the mid-flange away from the lower vessel section with the upper internals remaining suspended from the mid-flange so as to lift both the mid-flange and the suspended upper internals away from the lower vessel section;replacing fuel of the nuclear reactor core disposed in the lower vessel section; lowering the mid-flange back onto the lower vessel section with the upper internals remaining suspended from the mid-flange;reconnecting the upper vessel section to the lower vessel section; and re-pressurizing the nuclear reactor,wherein the nuclear reactor further includes a central riser disposed in the upper vessel section and riser cone connecting the central riser with the lower vessel section, the riser cone remaining disposed with the lower vessel section upon completion of the disconnecting and lifting of the upper vessel section away from the lower vessel section, the method further comprising:removing the riser cone prior to lifting the mid-flange away from the lower vessel section with the upper internals remaining suspended from the mid-flange. 10. The method of claim 9 wherein the mid-flange connects the upper and lower vessel sections. 11. The method of claim 10 wherein the mid-flange includes vessel penetrations connecting with the upper internals and the method further comprises:before lifting the mid-flange away from the lower vessel section, disconnecting external connections to the vessel penetrations of the mid-flange. 12. The method of claim 11 wherein the disconnecting of the upper vessel section from the lower vessel section also disconnects the mid-flange from the lower vessel section, the mid-flange remaining supported by the lower vessel section due to weight of the mid-flange and weight of the upper internals that remain suspended from the mid-flange. 13. The method of claim 9 wherein the nuclear reactor further includes a steam generator disposed inside and secured with the upper vessel section, and the steam generator remains disposed inside and secured with the upper vessel section during and upon completion of the disconnecting and lifting of the upper vessel section away from the lower vessel section.
052788750	summary	BACKGROUND OF THE INVENTION This invention relates to process for the synthesis of a labeled compound used for the positron emission tomography (PET) system which is one imaging diagnostic technology and apparatus therefor. A labeled compound used for the PET system is methyl iodide labeled with .sup.11 C which was synthesized using a synthesis apparatus as shown in FIG. 7. In this figure, the numeral 1 indicates a target gas cylinder which stores a mixed gas for the target, and the target gas cylinder 1 is connected with a target box 4 in which .sup.11 CO.sub.2 gas is produced by a transfer tube 3 through an electromagnetic valve 2. The target box 4 is connected with a collecting coil 8 by a transfer tube 7 through electromagnetic valves 5,6. A helium gas cylinder 9 is also connected with the collecting coil 8 by transfer tubes 11,7 through electromagnetic valves 10,6. The collecting coil 8 is put in a cooling vessel 12, and the outlet of the collecting coil 8 is connected with a reaction vessel 14 by a transfer tube 13. The reaction vessel 14 is further connected with a syringe 16 containing hydroiodic acid by a transfer tube 18 through an electromagnetic valve 17 as well as an exhaust tube 15. When methyl iodide labeled with .sup.11 C is synthesized using the above synthesis apparatus, the mixed gas for the target is filled into the target box 4 from the target gas cylinder 1 by opening the valve 2. Then, proton beam 19 supplied from a cyclotron (not shown) is irradiated for a fixed time to produce .sup.11 CO.sub.2 gas through a nuclear reaction (.sup.14 N(p.d).sup.11 C). Subsequently, the target gas containing .sup.11 CO.sub.2 is delivered to the collecting coil 8 cooled in the cooling vessel 12 through the valves 5,6, and .sup.11 CO.sub.2 gas is collected. After the collection is finished, the collecting coil 8 is heated to deliver .sup.11 CO.sub.2 gas to the reaction vessel 14 by supplying helium gas from the gas cylinder 9 through the valves 10,6. In the reaction vessel 14, .sup.11 CO.sub.2 gas is reduced by bubbling it into a reducing agent solution. Then, the reducing agent solution is evaporated by heating the reaction vessel, and discharged through the exhaust tube 15. Hydroiodic acid (HI) is introduced into the reaction vessel 14 by operating the syringe 16, and methyl iodide labeled with .sup.11 C (.sup. 11 CH.sub.3 I) is synthesized. Thereafter, .sup.11 CH.sub.3 I is recovered by heating the reaction vessel 14 again to distill it. In the above process of synthesizing methyl iodide, respective times for terminating bubbling, the distillation of the reducing agent solution and the supply of .sup.11 CO.sub.2 were decided from an average time necessary for these processes which was empirically decided by adding an excess time for the security. These times were inputted into an apparatus having a time control such as a microcomputer or a sequencer as a set point, and the finish of these processes was detected. In the above conventional process, since respective termination points of the bubbling, the distillation of the reducing agent solution and the supply of .sup.11 CO.sub.2 were decided empirically, these points were set considerably longer than the minimum time due to the variations of the bubbling time, the distillation time of the reducing agent solution and the supply time of .sup.11 CO.sub.2 caused by a delicate difference of conditions. However, the half life of .sup.11 C is about 20 minutes which is very short, and therefore, quenching of .sup.11 CO.sub.2 and .sup.11 CH.sub.3 I increased by the extension of the set points. As a result, it was difficult that both the utilization of .sup.11 CO.sub.2 and the recovery of .sup.11 CH.sub.3 I were kept always high. That is, it was impossible to satisfy both of decreasing the risk of failure in the synthesis and increasing the yield of .sup.11 CH.sub.3 I. Moreover, another problem is in a long time from the start of supplying .sup.11 CO.sub.2 to the recovery of .sup.11 CH.sub.3 I. SUMMARY OF THE INVENTION An object of the invention is to provide processes for the synthesis of .sup.11 C-labeled methyl iodide capable of improving both the utilization of .sup.11 CO.sub.2 and the recovery of .sup.11 CH.sub.3 I. Another object of the invention is to provide processes for the synthesis of .sup.11 C-labeled methyl iodide capable of recovering .sup.11 CH.sub.3 I in a short time. Still another object of the invention is to provide apparatus therefor. The present invention has been made in order to achieve the above objects, and is characterized by providing a radiation sensor in the vicinity of the reaction vessel and deciding the termination points of the bubbling and the evaporation of the reducing agent solution by the signal transmitted from the radiation sensor. Thus, a process for the synthesis of .sup.11 C-labeled methyl iodide of the invention comprises a .sup.11 CO.sub.2 -producing process of producing carbon dioxide gas labeled with .sup.11 C, a bubbling process of bubbling .sup.11 CO.sub.2 gas into a reducing agent solution in a reaction vessel, a .sup.11 CH.sub.3 I synthesis process of synthesizing .sup.11 CH.sub.3 I from an intermediate produced by the reduction in the bubbling process and a .sup.11 CH.sub.3 I distillation process of distilling .sup.11 CH.sub.3 I synthesized in the .sup.11 CH.sub.3 I synthesis process, and deciding the termination of the bubbling in the bubbling process and the termination of the distillation in the .sup.11 CH.sub.3 I distillation process based on the variation of the radiation emitted from the reaction vessel. An apparatus therefor comprises a target box in which .sup.11 CO.sub.2 gas is produced, a reaction vessel in which .sup.11 CH.sub.3 I is synthesized from .sup.11 CO.sub.2 gas and a radiation sensor provided in the vicinity of the reaction vessel. Another process for the synthesis of .sup.11 C-labeled methyl iodide of the invention is characterized by detecting the temperature in the reaction vessel by a temperature sensor and deciding the termination point of the evaporation of the reducing agent solution based on the temperature variation. Thus, the process comprises a .sup.11 CO.sub.2 -producing process of producing carbon dioxide gas labeled with .sup.11 C, a bubbling process of bubbling .sup.11 CO.sub.2 gas into a reducing agent solution in a reaction vessel, a reducing agent solution-removing process of evaporating the reducing agent solution after the termination of the bubbling, and a .sup.11 CH.sub.3 I synthesis process of synthesizing .sup.11 CH.sub.3 I from an intermediate produced by the reduction in the bubbling process and deciding the termination of the evaporation in the reducing agent solution-removing process based on the variation of the temperature in an exhaust tube for discharging the vapor of the reducing agent solution connected with the reaction vessel. An apparatus therefor comprises a target box in which .sup.11 CO.sub.2 gas is produced, a reaction vessel in which .sup.11 CH.sub.3 I is synthesized from .sup.11 CO.sub.2 gas and a temperature sensor for detecting the temperature of an exhaust tube for discharging the vapor of the reducing agent solution reducing .sup.11 CO.sub.2 gas. The other process for the synthesis of .sup.11 C-labeled methyl iodide of the invention is characterized by providing a radiation sensor on the introducing side of .sup.11 CO.sub.2 gas and deciding the termination point of the supply of .sup.11 CO.sub.2 gas based on the signal transmitted from the radiation sensor. Thus, the process comprises a .sup.11 CO.sub.2 -producing process of producing carbon dioxide gas labeled with .sup.11 C, a .sup.11 CO.sub.2 -supplying process of supplying .sup.11 CO.sub.2 gas produced in the .sup.11 CO.sub.2 -producing process to a reaction vessel and a .sup.11 CH.sub.3 I synthesis process of synthesizing .sup.11 CH.sub.3 I from .sup.11 CO.sub.2 gas, and deciding the termination of the supply of .sup.11 CO.sub.2 gas in the .sup.11 CO.sub.2 -supplying process based on the variation of the radiation on the introducing side of .sup.11 CO.sub.2 gas. An apparatus therefor comprises a target box in which .sup.11 CO.sub.2 gas is produced, a reaction vessel in which .sup.11 CH.sub.3 I is synthesized from .sup.11 CO.sub.2 gas, a transfer tube connecting the target box with the reaction vessel, a radiation-detecting part provided at the transfer tube, and a radiation sensor provided in the vicinity of the radiation-detecting part.
	claims	1. A transportable nuclear generator, comprising:a reactor power module comprising a nuclear core, control systems, and coolant flow reversing structure, wherein the reactor power module is configured to burn a nuclear fuel to generate thermal energy in a coolant/working fluid;a power conversion module comprising turbo-machinery equipment and heat exchangers, wherein the power conversion module is configured to receive the thermal energy from the coolant/working fluid from the reactor power module and to generate mechanical energy; anda power generation module comprising a fast generator-motor, electronic controllers and uninterruptable power sources, wherein the power generation module is configured to receive mechanical energy from the power conversion module and to generate electrical energy,wherein the reactor power module, the power conversion module, and the power generation module are configured to be thermo-hydraulically coupled to one another to form an operational nuclear reactor as a single vessel. 2. The transportable nuclear generator of claim 1, wherein the reactor power module, the power conversion module, and the power generation module are configured to be interchangeably assemblable in a horizontal or vertical configuration. 3. The transportable nuclear generator of claim 1, wherein the reactor power module, the power conversion module, and the power generation module are further configured to be passively cooled via natural coolant-circulation across heat transfer surfaces. 4. The transportable nuclear generator of claim 1, wherein the reactor power module, the power conversion module, and the power generation module are further configured to operate as a self-contained unit without requiring external piping or equipment. 5. The transportable nuclear generator of claim 1, wherein the reactor power module comprises a melt-proof thermally conductive ceramic nuclear core. 6. The transportable nuclear generator of claim 1, further comprising coolant pathways defined by internal fins with low fluid-dynamic drag that provide core structural support while ensuring transfer of decay thermal energy from the core to external fins by conduction heat transfer mechanisms, wherein the coolant pathways are configured to safely and passively transfer decay thermal energy to an environment surrounding the transportable nuclear generator even in the total absence of coolant. 7. The transportable nuclear generator of claim 1, wherein the reactor power module further comprises at least one of the following reactivity control systems:(1) control rods or rotary control drums in a neutron reflector, containing neutron absorbing and reflecting materials configured to be passively engaged in absorbing mode for safety;(2) an array of in-core control rods;(3) an emergency shutdown system that injects neutron poison into the core through a passive system. 8. The transportable nuclear generator of claim 1, further comprising an inert gas as coolant and working fluid for the power conversion module. 9. The transportable nuclear generator of claim 1, wherein the reactor power module, the power conversion module, and the power generation module are further configured to perform a regenerative Brayton cycle to generate electricity. 10. The transportable nuclear generator of claim 1, further comprising:a primary loop fully enclosed in the reactor power module;water as a coolant and moderator circulating in the primary loop;one or more integral separation heat exchangers configured to provide thermal coupling between the primary loop in the reactor power module and a secondary loop in the power conversion module;water circulating in the secondary loop that receives thermal energy from the primary loop to generate superheated steam, wherein water in the secondary loop transfers thermal energy to the integral turbo-machinery in the power conversion module in the form of superheated steam to generate electricity according to a Rankine power cycle; andan integral condenser, wherein after expanding in the turbo-machinery, steam is vented to the integral condenser which passively transfers thermal energy to internal and externally extended cooling fins of the power conversion module to condense the steam. 11. The transportable nuclear generator of claim 10, further comprising one or more pumps that re-pressurize condensed steam and pump the resulting sub-cooled water at an inlet of a secondary side of the separation heat exchanger into the secondary loop. 12. The transportable nuclear generator of claim 1, further comprising:a primary loop fully enclosed in the reactor power module;liquid metal as coolant actively circulated by recirculation pumps in the primary loop;one or more integral separation heat exchangers configured to provide thermal coupling between the primary loop in the reactor power module and a secondary loop in the power conversion module;gas or water circulating in the secondary loop,wherein when gas is circulating in the secondary loop, the turbo-machinery is configured to satisfy the requirements of a regenerative Brayton power cycle, andwherein when water is circulating in the secondary loop, the turbo-machinery is configured to satisfy Rankine power cycle requirements. 13. The transportable nuclear generator of claim 1, further comprising:rotary components forming the turbo-machinery in the power conversion module;rotary components forming a generator-motor of the power generation module;a rotary shaft that connects the rotary components forming the turbo-machinery in the power conversion module and the rotary components forming a generator-motor of the power generation module in the form of a direct mechanical coupling so that the rotary components forming the turbo-machinery and the rotary components forming a generator-motor rotate with a common speed,wherein the rotational speed of the shaft is determined by the thermal-hydraulics of the power conversion system, loading conditions and settings of the electronic control system regulating the electric generator-motor machine, andwherein a frequency and other electrical parameters of the generator power are controllable by integral electronic conditioning circuits. 14. The transportable nuclear generator of claim 13, wherein:the generator-motor generates electricity during operation of the transportable nuclear generator,the generator-motor drives the turbo-machinery of the power conversion module during startup and after shutdown, andstartup power is provided to the generator-motor during startup through uninterruptable power sources or an external source of electric power. 15. The transportable nuclear generator of claim 1, wherein the reactor power module is further configured to allow removal of a reactor power module containing fresh or spent nuclear fuel and replacement with a new reactor power module having fresh nuclear fuel. 16. The transportable nuclear generator of claim 1, further comprising heat exchangers for the production of low-and/or high-grade process heat to be distributed to equipment dedicated to desalination, bio-fuel processing, district heating, or other industrial uses. 17. A method of generating electricity, comprising:providing the transportable nuclear generator of claim 1; andoperating the transportable nuclear generator in one of the following modes:(1) according to a regenerative Brayton power cycle to generate electricity using an inert gas as a working fluid;(2) according to a Rankine power cycle to generate electricity when water is used as a working fluid. 18. The method of claim 17, further comprising operating the transportable nuclear generator in a horizontal or vertical configuration. 19. The method of claim 17, wherein the transportable nuclear generator further comprises:integrated heat exchangers formed by internal and external fins configured to provide passive cooling; andan emergency shutdown system that injects neutron poison into the core through a passive system if other systems fail. 20. A method of refueling a transportable nuclear generator, the method comprising: providing the transportable nuclear generator of claim 15;removing a first reactor power module having fresh or spent nuclear fuel; and replacing the first reactor power module with a second reactor power module having fresh nuclear fuel. 21. The transportable nuclear generator of claim 5, wherein the melt-proof thermally conductive ceramic nuclear core further comprises:monolithic fuel elements (MTF) comprising tri-structural isotropic (TRISO) fissile fuel sealed in SiC pellets. 22. The transportable nuclear generator of claim 21, wherein the SiC pellets are nano-infiltration and transient eutectic-phase (NITE) sintered pellets. 23. The transportable nuclear generator of claim 21, wherein the MTF elements comprise the TRISO fissile fuel SiC pellets sealed into SiC or SiC-composite elements. 24. The transportable nuclear generator of claim 21, wherein the TRISO fuel pellets further comprise a layer of unfueled SiC surrounding a fueled region. 25. The transportable nuclear generator of claim 21, wherein the TRISO fuel pellets further comprise an oxide, carbide, oxy-carbide or a nitride of uranium, plutonium, thorium or other fissile isotope. 26. The transportable nuclear generator of claim 21, wherein the TRISO fuel pellets further comprise a burnable poison rare earth oxide comprising erbia or gadolinia incorporated in the SiC pellets. 27. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises non-fuel coated particles comprising a burnable poison. 28. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises fuel elements comprising a composite structure of unidirectional fiber-reinforced NITE-sintered SiC with SIC fibers. 29. The transportable nuclear generator of claim 21, wherein the TRISO fuel pellets further comprise a high-density non-porous SiC coating. 30. The transportable nuclear generator of claim 21, wherein:the MTF elements comprise rectangular blocks, hexagonal blocks, or quarter-circle plates, andwherein the MTF elements comprise holes that provide flow pathways for a coolant. 31. The transportable nuclear generator of claim 30, further comprising:neutron reflector elements comprising carbon or SiC,wherein the neutron reflector elements are geometrically configured to correspond to the geometric configuration of the MTF elements. 32. The transportable nuclear generator of claim 30, wherein the MTF elements are spaced so as to eliminate gaps between MTF elements to thereby enhance the thermal conductivity of the conductive ceramic core and to enhance core passive heat transfer properties. 33. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises:pressure plates provided at an inlet and outlet of the core,wherein the pressure plates comprise matching coolant holes that provide flow pathways for a coolant, andwherein the pressure plates are configured to provide a compressive force that keeps the core under compression. 34. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises:fuel rods containing nuclear fissile material in the form of oxide, nitride, or metal, with metallic or ceramic cladding and arranged in bundles. 35. The transportable nuclear generator of claim 34, wherein the bundles are geometrically arranged so as to have favorable heat transport properties relative to a coolant. 36. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises loose fuel elements in the form of spherical pebbles. 37. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core is configured to allow passive cooling even in the absence of a coolant. 38. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises control rods, made of a sintered mix of SiC-Gd203 and Er203 and control rod sleeves. 39. The transportable nuclear generator of claim 21, wherein the melt-proof thermally conductive ceramic nuclear core further comprises control rod channels made of fiber-reinforced carbon or SiC composite materials. 40. The transportable nuclear generator of claim 21, wherein the MTF elements comprise partial cuts to allow for controlled fracturing of the MTF elements without cracks propagating into the TRISO fuel pellets in the event that the transportable nuclear generator is subjected to severe kinetic stresses or impacts.
	abstract	The invention relates to an optical device that includes (a) a first optical element with at least one first raster element, where the first raster element has a first axis, (b) a second optical element with at least one second raster element, where the second raster element has a second axis. The first raster element can be changed in its position relative to the second raster element, so that a distance between the first axis and the second axis is variable.
	abstract	The present invention relates to a process for sintering a compacted powder of at least one oxide of a metal selected from an actinide and a lanthanide, this process comprising the following successive steps, carried out in a furnace and under an atmosphere comprising an inert gas, dihydrogen and water: (a) a temperature increase from an initial temperature TI up to a hold temperature TP, (b) maintaining the temperature at the hold temperature TP, and (c) a temperature decrease from the hold temperature TP down to a final temperature TF, in which the P(H2)/P(H2O) ratio is such that: 500<P(H2)/P(H2O)≤50 000, during step (a), from TI until a first intermediate temperature Ti1 between 1000° C. and TP is reached, and P(H2)/P(H2O)≤500, at least during step (c), from a second intermediate temperature Ti2 between TP and 1000° C., until TF is reached.
	claims	1. An assembly for refueling a nuclear reactor having a reactor core including a plurality of elongated core components positioned in a reactor pool, a reactor pool bridge positioned above and movable over the reactor pool, a fuel pool, a fuel pool bridge positioned above and movable over the fuel pool, and a transfer pool fluidly coupling the fuel pool to the reactor pool, the assembly comprising:a handover assembly selectively positionable within a transfer channel and having at least two compartments each configured for selectively securing one of the core components in a vertical position, the handover assembly being movable to allow a reactor pool grapple operating from the reactor pool bridge and a fuel pool grapple operating from the fuel pool bridge to each simultaneously retrieve a core component from one of the compartmentswherein the handover assembly includes a mast with the compartments attached thereto, the mast and attached compartments rotatably coupled in a permanently fixed position about a lower portion of the fuel pool bridge and extending downward, the mast and compartments being substantially aligned with the transfer channel and dimensioned to enable at least a 90 degree rotation of the mast and the at least two compartments within the transfer channel. 2. The refueling assembly of claim 1, further comprising a trolley movably coupled about a portion of the fuel pool bridge, wherein the mast is coupled to the trolley and extends downward, the compartments being positioned about the mast and a lifting assembly configured to raise and lower the fuel pool grapple and a core component engaged by the fuel pool grapple. 3. The refueling assembly of claim 2 wherein the trolley includes an extension assembly configured to extend the handover assembly from the fuel pool bridge and the trolley and into the transfer channel. 4. The refueling assembly of claim 1, further comprising a hoist and a cable coupled to the fuel pool grapple and operable from the fuel pool bridge to raise and lower the fuel pool grapple and access each of the compartments, the fuel pool grapple being configured to temporarily secure a component and install and retrieve components from each of the compartments. 5. The refueling assembly of claim 1 wherein the handover assembly includes an elongated body extending downward and defining the at least two compartments each having an elongated shape, each compartment having at least one substantially open side for allowing the lateral passage of a component into and out of the compartment, and a latch to selectively laterally secure the core component vertically positioned within the compartment. 6. The refueling assembly of claim 5 wherein each compartment includes a bottom aperture and a bottom plate movable to selectively close the bottom aperture, the bottom plate being configured to hold the core component vertically within the compartment and movable to an open position to enable the core component to exit from the bottom aperture responsive to a remote command. 7. The refueling assembly of claim 1 wherein the handover assembly includes a first compartment for securing a first fuel assembly and a second compartment for securing a second fuel assembly. 8. The refueling assembly of claim 7 wherein the first and second compartments are positioned on a first side of the handover assembly, the handover assembly includes a third compartment positioned on a second side substantially opposing the first side and being configured to receive and secure a core component selected from the group consisting of a double blade guide, a control rod, and a control rod tube, wherein the handover assembly is rotatable to allow the independent selective access to each of the first, second and third compartments by the fuel pool grapple and the reactor pool grapple. 9. The refueling assembly of claim 1, further including a handover assembly control system configured to control an operation of the handover assembly. 10. The refueling assembly of claim 9 wherein the control system is configured to prevent a movement of the handover assembly through the transfer channel in a direction of the reactor pool when a leading compartment secures a core component. 11. The refueling assembly of claim 1, further comprising a transfer channel bridge positioned above the transfer channel, the handover assembly being rotatably coupled beneath the transfer channel bridge. 12. The refueling assembly of claim 11 wherein the transfer channel bridge is substantially fixed in position during refueling and removable when not in use. 13. The refueling assembly of claim 11 wherein the handover assembly includes only two compartments, a first compartment being positioned about 180 degrees and substantially apart from a second compartment. 14. An assembly for refueling a nuclear reactor having a reactor core in a reactor pool through a transfer channel to a storage rack in a fuel pool, the assembly comprising:a handover assembly having at least two compartments each configured to selectively secure at least one component of the core in a vertical position, the handover assembly being positionable within the transfer channel;a reactor pool bridge positioned above and movable over the reactor pool and including a reactor pool transfer assembly having the reactor pool grapple configured to engage a spent core component from the core and transfer the spent core component to at least one of the compartments of the handover assembly; anda fuel pool bridge positioned above and movable over the fuel pool and including a fuel pool transfer assembly having the fuel pool grapple configured to engage a replacement core component within the fuel pool and transfer the replacement core component from the fuel pool to at least one of the compartments of the handover assembly, a trolley movable along the fuel pool bridge perpendicular to the movement of the reactor pool bridge over the reactor pool, wherein the handover assembly is rotatably coupled beneath the trolley and wherein the trolley includes an extension assembly configured to extend the handover assembly from the fuel pool bridge and the trolley and into the transfer channel,the assembly being configured to allow the reactor pool grapple and the fuel pool grapple to each simultaneously retrieve a core component from one of the compartments. 15. The refueling assembly of claim 14 wherein the handover assembly includes an elongated body defining the at least two compartments, each compartment including a latch configured to laterally secure a core component vertically within the compartment, the latch being responsive to a remote instruction. 16. The refueling assembly of claim 15 wherein each compartment includes a bottom plate configured to vertically hold the core component within the compartment, the bottom plate being movable to enable the core component to selectively exit from a bottom aperture of the compartment. 17. The refueling assembly of claim 14 wherein the handover assembly includes a first compartment configured to secure a first fuel assembly and a second compartment configured to secure a second fuel assembly, wherein the first and second compartments are positioned on a first side of the handover assembly and wherein the handover assembly includes a third compartment positioned on a side substantially opposing the first side, the third compartment being configured to secure at least one of a double blade guide, a control rod, and a control rod tube, wherein the first compartment is positioned on a first side of the handover assembly and the second compartment is positioned on an opposing side and substantially apart from the first compartment. 18. The refueling assembly of claim 14, further including a handover assembly control system for controlling an operation of the handover assembly including restricting the movement of the handover assembly within the transfer channel when a compartment securing a core component is positioned in a direction towards the reactor pool. 19. An assembly for refueling nuclear reactor comprising:a handover assembly for transferring one or more elongated core components between a reactor core pool and a fuel pool through a transfer channel in a vertical position, the handover assembly including two or more compartments for temporarily securing two different core components each in a vertical position;a reactor pool bridge for moving at least one of the core components within the reactor core pool to deliver and retrieve the at least one core component from at least one of the compartments of the handover assembly; anda fuel pool bridge for moving at least one of the core components within the fuel pool to deliver and retrieve the at least one core component from at least one of the compartments of the handover assembly,wherein the assembly is configured to allow the reactor pool bridge and the fuel pool bridge to each simultaneously retrieve the respective core components from the compartments of the handover assembly.
	description	The present invention relates generally to inspection of boiling water reactors and more specifically to visual inspection of top guides of boiling water reactors. Conventionally, inspection of grid beams forming top guide structures in boiling water reactors are performed by an In-Vessel Visual Inspection (IVVI) Level II inspector and camera handler hanging a camera handled by its cable from a refuel bridge or an auxiliary bridge. This method may be time consuming, may expend too much dose and may not provide stability necessary for such an inspection. U.S. Pat. No. 5,692,024 discloses an underwater crawler vehicle that rides on the top edges of two parallel grid members of a top guide structure and positions an inspection system to enable volumetric inspection of each grid member. The inspection system includes an ultrasonic inspection instrument to inspect the top guide structure. A tool for inspecting a cell formed by grid beams of a top guide structure in a nuclear reactor is provided. The tool includes a camera; a support structure coupled to the camera for contacting at least one of the grid beams to support the camera within the cell; and at least one actuator moving the camera with respect to the support structure and along one of the grid beams, the at least one actuator coupling the camera to the support structure. A method for inspecting a cell formed by grid beams of a top guide structure in a nuclear reactor is also provided. The method includes providing a tool including a camera within the cell so that the tool contacts at least one of the grid beams and sits within the cell; and inspecting a first grid beam of the grid beams while the tool sits within the cell by moving the camera along the first of the grid beams. FIG. 1 schematically shows a boiling water reactor vessel 50 inside of a containment building. A head of vessel 50 has been removed, along with a dryer and a steam separator of vessel 50 in order to allow inspection of a top guide structure inside of vessel 50. Workers may view and access the inside of vessel 50 with tools by using a refueling bridge 52 that passes over vessel 50. FIG. 2 schematically shows a plan view of a top guide structure 60. Top guide structure includes a grid structure 62 formed by a plurality of beams 64. Beams 64 each include slots formed on upper and lower surfaces of beams 64 so that slots of overlapping beams 64 can be mated to form grid structure. Intersecting beams 64 form a plurality of cells 66, which vertically orient fuel assemblies inside of reactor vessel 50 (FIG. 1). FIG. 3 schematically shows a perspective view of an exemplary section 68 of grid structure 62 shown in FIG. 2 in which four grid beams 64a, 64b, 64c, 64d intersect to define one exemplary cell 66. Grid beams 64a, 64b, 64c, 64d each include slots formed therein for mating at assembly areas 72ab, 72bc, 72cd, 72ad (i.e., corners of cells 66). For example, at assembly area 72ab, the top half of beam 64b is removed to form a slot in beam 64b and the bottom half of beam 64a is removed to form a slot in beam 64a and beams 64a, 64b are mated via there slots. Beams 64c, 64d each include cutout portions on lower surfaces of beams 64c, 64d that form an instrumentation pocket 70 where an instrumentation plunger can be inserted. A plurality of instrumentation pockets 70 may be formed throughout grid structure 62 (FIG. 2). FIGS. 4 and 5 schematically show perspective views of an inspection tool 10 according to an embodiment of the present invention for inspecting a top guide structure in a nuclear reactor, for example, top guide structure 60 (FIG. 2) of boiling water reactor vessel 50 (FIG. 1). Inspection tool 10 includes a video camera 12, an auxiliary light 16 connected to camera 12 by a bracket 20a of a light and camera mount 20, an actuation device 110 connected to camera 12 and a support structure 120 connected to actuation device 110 for mounting tool 10 within one of cells 66 (FIG. 2). Light and camera mount 20 also includes an upper portion 20b that couples light 16 and camera 12 to actuation device 110. Camera 12 includes a right angle lens 14 at a lower end of camera 12. When placed within one of cells 66 of top guide structure 60 (FIG. 2), for example cell 66 defined by grid beams 64a, 64b, 64c, 64d shown in FIG. 3, camera 12 is aligned vertically and right angle lens 14 is positioned to allow video camera 12 to capture images of portions of the grid beams 64a, 64b, 64c, 64d that are in an area that is horizontally adjacent to right angle lens 14 (i.e., approximately perpendicular to lens 14). Light 16 may be aligned parallel to camera 12 above right angle lens 14. Light 16 is positioned with respect to right angle lens 14 such that light 16 illuminates the surface of cell 66 that is facing right angle lens 14. Actuation device 110 includes a vertical slide 22 and a horizontal slide 24. An upper portion of camera 12 is coupled to a vertical slide block assembly 23 of vertical slide 22, which is substantially parallel to camera 12. Vertical slide 22 may adjust a vertical position of right angle lens 14 and light 16 with respect to support structure 120. Vertical slide 22 may be coupled to a horizontal slide block assembly 25 of horizontal slide 24. Vertical slide 22 and horizontal slide 24 may each include respective reversible air motors, internal gear heads and lead screws for moving respective block assemblies 23, 25. The use of air motors may be advantageous in the area of top guide structure 60 (FIG. 2) because air motors are tolerant of the very high dose rate and the temperature in the area of top guide structure 60. The motors may be used with the integral gear heads to drive the lead screw of each slide 22, 24. Horizontal slide 24 may move vertical slide 22 horizontally, adjusting the horizontal position of right angle lens 14 and light 16. Support structure 120 includes a base plate 26, guides 34, 36, 38, 40 and a handle 44. Horizontal slide 24 is mounted on a base plate 26. In this embodiment, base plate 26 includes a main portion 28 supporting horizontal slide 24 and two side extensions 30, 32 that are coplanar with main portion 28 and extend away from main portion 28 and horizontal slide 24. Base plate 26 surrounds lens 14 and light 16 on three sides and are positioned with respect to lens 14 and light 16 so as not to obstruct the recording by lens 14 on a forth side. Guides 34, 36, 38, 40 extend vertically downward from corners of base plate 26, with guides 34, 40 being coupled to ends of side extensions 30, 32, respectively, and guides 36, 38 being coupled to ends of main portion 28. Tool 10 may be clamped into position within a cell of the top guide structure by a clamp 42 that may include a pneumatic cylinder for pushing against one of beams 64a, 64b, 64c, 64d (FIG. 3). Handle 44 includes vertical uprights 44a, 44b coupled to base plate 26 and a horizontal beam 44c connecting vertical uprights 44c so that handle 44 extends around camera 12 and vertical slide 22. At least one pole 46 is a connected to horizontal beam 44c. A cam 48 may be connected to mount 20 or camera 12 for horizontally turning camera 12. A first arm of cam 48 contacts vertical upright 44a to rotate camera 12 horizontally in a first direction and a second arm of cam 48 contacts vertical upright 44b to rotate camera 12 horizontally in a second direction. Tool 10 may be delivered into one of cells 66 of top guide structure 60 by pole 46 from a refueling bridge or an auxiliary bridge located above the nuclear reactor. Umbilicals (e.g., system hoses for slides 22, 24 and clamp 42 and cables for camera 12 and light 16) for operating tool 10 may be managed by attaching the umbilicals to the poles. Slides 22, 24 and clamp 42 may be controlled by a pneumatic control panel mounted on a hand rail of refueling bridge 52 (FIG. 1). The pneumatic control panel may include valves that can be manually operated by a worker. In a preferred embodiment, slides 22, 24 may move at speed of approximately 0.5 inch per second and approximately 140 psi air may be provided to the air motors. The stability of tool 10, when mounted within one of cells 66 of top guide structure 60 may advantageously allow camera 12 to provide high quality video. Tool 10 allows the bottom two inches of grid beams 64 of interior surfaces of grid beams 64 in the cell 66 to be inspected, along with assembly areas 72 of the interlocking grid beams 64 and instrumentation pockets 70. FIG. 6 schematically shows tool 10 mounted within one of cells 66. Base plate 26 rests on the top surfaces of grid beams 64a, 64b, 64c, 64d and guides 34, 36, 36, 38 (FIGS. 4, 5) are in contact with corners of cell 66. Camera 12 extends downward into cell 66 to record images of areas of interest of grid beams 64a, 64b, 64c, 64d. In one preferred embodiment of an inspection method of the invention, fuel assemblies are removed from cell 66 before tool 10 is inserted into cell 66 by one or more workers holding pole 46. Once tool 10 is positioned in cell 66 such that base plate 26 rests on the top surfaces of grid beams 64a, 64b, 64c, 64d and guides 34, 36, 36, 38 (FIGS. 4, 5) are in contact with corners of cell 66, clamp 42 is forced against the interior of grid beam 64c. Camera 12 is then moved horizontally by horizontal slide 24 towards an interior corner of cell 66. As camera 12 approaches the interior corner of cell 66, the first arm of cam 48 contacts vertical upright 44a and rotates camera 12 and light 16 for example approximately twenty-five degrees horizontally so that right angle lens 14 faces and light 16 illuminates assembly area 72ab (FIG. 3) of cell 66. While camera 12 and light 16 are held in this angled orientation by the contact between the first arm of cam 48 and vertical upright 44a, camera 12 and light 16 are moved vertically by vertical slide 22 so that camera 12 can inspect the assembly area 72ab (FIG. 3) where grid beams 64a and 64b intersect. Camera 12 may only inspect the bottom half of assembly area 72ab (FIG. 3) (e.g., where edges of slots of beams 64a, 64b contact each other). After assembly area 72 of grid beams 64a and 64b is inspected, camera 12 is moved vertically downward by vertical slide 22 so that right angle lens 14 is vertically positioned to inspect approximately the bottom two inches of grid beam 64a. Camera 12 and light 16 are moved horizontally by horizontal slide 24 along the bottom edge of grid beam 64a. As camera 12 and light 16 are moved away from the interior corner defined by grid beams 64a, 64b, the first arm of cam 48 comes out of contact with vertical upright 44a and camera 12 is rotated back so that right angle lens 14 faces the interior surface of grid beam 64a. Horizontal slide 24 moves camera 12 horizontally until the second arm of cam 48 contacts vertical upright 44b. The second arm of cam 48 contacts vertical upright 44b to rotate camera 12 for example approximately 25 degrees horizontally so that right angle lens 14 faces and light 16 illuminates assembly area 72ad (FIG. 3) of cell 66 formed by the intersection of grid beams 64a, 64d. While camera 12 and light 16 are held in this angled orientation by the contact between the second arm of cam 48 and vertical upright 44b, camera 12 and light 16 are moved vertically by vertical slide 22 so that camera 12 can inspect the assembly area 72ad (FIG. 3). After assembly area 72 of grid beams 64a and 64b is inspected, camera 12 may be horizontally and vertically centered in tool 10. Clamp 42 may then be brought out of contact with grid beam 64c so that tool 10 can be removed from cell 66 by workers on refueling bridge 52 via polls of tool 10. Workers may rotate tool ninety degrees and insert tool 10 back into cell 66 so that for example grid beam 64b may be inspected in the same manner as grid beam 64a. The process described above can then be used to inspect grid beams 64c, 64d to complete inspection of cell 66. Tool 10 can then be moved by the workers to a different cell to inspect the different cell in the same manner. During each refueling event approximately five to ten cells may be inspected. In one preferred embodiment, camera 12 may be calibrated inside of cell 66 by a card mounted one of beams 64a, 64b, 64c, 64d. This may advantageously allow prevent camera 12 from becoming uncalibrated during the process of mounted tool 10 within cell 66. In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.
047770163	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to FIGS. 1, 2 and 3. FIG. 1 is a longitudinal section view of a fuel assembly for a boiling water reactor and FIG. 2 is a horizontal section view of the same fuel assembly. The fuel assembly comprises upper and lower tie plates 1 and 2, a plurality of fuel rods 4, a large central water rod 5, spacers 3 and a channel box 8 enclosing them. The fuel rods 4 and the large central water rod 5 are arranged in such a configuration as shown in FIG. 2. The fuel rods 4, each of which consists of a cladding of zircaloy, upper and lower end plugs 13, 16 and fuel pellets inserted in the cladding, are held by the upper and lower tie plates 1, 2. The lower end plug 13 of each of the fuel rods 4 is inserted in a hole of the lower tie plate 2 and the upper end plug 16 is loosely inserted in a hole of the upper tie plate 1 so that the upper end of the fuel rod 4 can move in an axial direction. Expansion springs 18, each of which is made of inconel and wound around the upper end plug 16, are inserted between the end portions of the fuel rods 4 and the upper tie plate 1 so as to support the upper tie plate 1. Among the sixty fuel rods 4, the eight fuel rods indicated by a reference numeral 7 constitute tie rods and serve also to join the upper and lower tie plates 1, 2 to each other. The spacers 3, each of which consists of a zircaloy frame and inconel springs, serve to maintain lateral spacings among the fuel rods 4 and the large central water rod 5. Seven (7) of the spacers 3 are axially distributed between the upper and lower tie plate 2, 1. The channel box 8 made of zircaloy encloses the fuel rods 4 and the lower and upper ends of the channel box 8 are fitted to the lower and upper tie plates 2, 1, respectively. The large central water rod 5 is disposed among the fuel rods 4, to be positioned at the central portion of the fuel assembly. The large central water rod 5, the diameter of which is larger than that of the fuel rod 4, is not provided with an upper end plug and an expansion spring, and it is closed at its upper end and has a lower end plug 13. The side surface of the water rod 5 is provided with upper holes 14 at the upper side portion, lower holes 15 at the lower side portion, and a coolant of water is passed through the water rod 5 via the holes 14, 15. The water rod 5 is further provided with tabs for supporting the spacers 3. The water rod 5 is held by the lower tie plate 2 with the lower end plug 13 being inserted in a bore of the lower tie plate 2, and by the spacers 3. In the interior of the fuel assembly having the abovedescribed construction, water flows to remove the thermal energy which is generated through a reaction of a fission substance in the fuel rods 4. The water also flows in the spaces among the fuel assemblies. The fast neutrons flying out into the water turn into moderated thermal neutrons due to the water. When such thermal neutrons collide with a fission substance, a fission reaction occurs. In this embodiment, the large central water rod 5 has an outer diameter of 34.8 mm and a thickness of 1.1 mm. The large central water rod 5 occupies a space corresponding to that occupied by four fuel rods 4. The length of the large central water rod 5 is shorter than that of the fuel rod 4. FIG. 3 is a schematic diagram showing the position of the upper end of the large central water rod 5. In the fuel assembly in this embodiment, the each fuel rod 4 consists of an effective fuel portion 41 filled with fuel pellets, or effective enriched fuel section 41, and a plenum 42 provided on the upper side of the effective fuel portion 41. The position of the upper end of the large central water rod 5 is set substantially as high as that of the upper end of the effective fuel portion 41. Setting these two positions to a substantially equal height means that the upper end of the large central water rod 5 is set slightly higher than that of the effective fuel portion 41 taking the irradiation growth of the effective fuel portion 41, which causes the same portion to expand by about 5 cm, into consideration. It is known that by providing a large central water rod, the distribution of thermal neutron flux in a fuel assembly may become uniform and may cause the simplification of the enrichment distribution and an increase in the reactivity, which enable the economical efficiency of the fuel to be improved. However, when the large central water rod having the same length as the fuel rod is provided in the central portion of a fuel assembly, the cross-sectional area of a flow passage for the coolant decreases. Therefore, there is the possibility that the fuel cooling characteristics are deteriorated with the fuel thermal margin decreasing. Such fuel cooling characteristics are featured by the pressure loss of the coolant flowing in the fuel assembly. Namely, an increase in the pressure loss causes the fuel cooling characteristics to be deteriorated, and a decrease in the pressure loss causes the fuel cooling characteristics to be improved. The friction pressure loss .DELTA.P.sub.f due to a steam-liquid two phase flow in a boiling water reactor is generally expressed by the following equation: ##EQU1## wherein .DELTA.P.sub.f is a friction pressure loss, W a flow rate in a channel, g gravitational acceleration, .rho. density of water, D.sub.H a hydraulic diameter of the channel, A.sub.CH a cross-sectional area of a flow passage in the channel, L a length, f a friction pressure loss coefficient, and .phi..sub.TPF a friction factor multiplifier for the two-phase flow. When the large-diameter water rod is provided instead of four fuel rods in the central portion of the fuel assembly the cross-sectional area A.sub.CH of a water flow passage exclusive of the interior of the large-diameter water rod in the channel box decreases, so that a friction pressure loss .DELTA.P.sub.f increases. In order to prevent this increase in the friction pressure loss, a step of reducing the length L of a portion, in which a pressure loss occurs, is taken. In this embodiment, the length of the large-diameter water rod is reduced to a suitable length to form the above-described large central water rod 5, for the purpose of reducing the length L of a portion in which a pressure loss occurs. Since the original object of installing the large-diameter water rod resides in the improving of the nuclear characteristics of the effective fuel portion, i.e., the levelling of the distribution of thermal neutron flux in the fuel assembly, it is satisfactory that this large central water rod 5 has the large diameter up to the position which is as high as the upper end of the effective fuel portion of the fuel rod 4. In view of these facts, the large central water rod 5 is employed in this embodiment, the upper end of which water rod 5 is set substantially as high as the upper end of the effective fuel portion 41 of the fuel rod 4. In the above embodiment, the whole of the effective fuel portion of the fuel rod is filled with enriched fuel pellets. In order to improve the economical efficiency of fuel and increase a shutdown margin of the core, it is effective to provide a natural uranium blanket region on the upper end of the effective fuel portion. Another embodiment of the present invention, in which a natural uranium blanket region is provided on the upper end of each effective fuel portion, will now be described referring to FIGS. 4, 5. FIG. 4 is a schematic diagram showing the height of the upper end of a large central water rod 5A in comparison with that of the upper end of an effective fuel portion, on which a natural uranium blanket region is provided, of a fuel rod 4A. In this embodiment, the effective fuel portion consists of an effective enriched fuel section 41A and a natural uranium blanket region 43 provided on the section 41A, and a plenum 42A is positioned on this natural uranium blanket region 43. The height of the upper end of the large central water rod 5A is set substantially equal to that of the upper end of the effective enriched fuel section 41A, i.e. the lower end of the natural uranium blanket region 43, and not the upper end of the effective fuel portion. The large central water rod 5A is not extended to the height which is equal to that of the upper end of the natural uranium blanket region taking the nuclear characteristics of the same region into consideration. The matter will further be described. In general, the infinite multiplication factor of a fuel attains its maximum level when the quantity of moderator is increased, and it tends to decrease when the quantity of moderator is increased after the maximum level has been attained. FIG. 5 shows a relationship between the infinite multiplication factor K.sub..infin. of a fuel and the quantity of moderator. The atomic ratio of hydrogen to uranium (H/U ratio) is taken along the lateral axis of FIG. 5. When the quantity of water as a moderator is increased, the H/U ratio increases. The infinite multiplication factor has a maximum value with respect to the quantity of moderator for the following reasons. When the H/U ratio increases, the moderation of neutrons is promoted. Consequently, the resonance escape probability P increases, while the thermal neutron absorption rate of the moderator also increases. Accordingly, the thermal utilization factor f decreases, and P and f offset each other. A fuel for a boiling water reactor is within the range of insufficient moderation, which corresponds to the region A in FIG. 5, in a regular operational region thereof, in which the reactor is kept in an easily-self-controllable state with the power reactivity coefficient set in a negative level. However, since the content of uranium 235 of natural uranium is 1/3-1/4 of that of a regular enriched fuel, the thermal neutron absorption cross section of uranium 235 decreases, and the thermal utilization factor f also decreases. Also, a total thermal neutron absorption cross section decreases, so that the percentage of the thermal neutron absorption cross section of the moderator relatively increases. Therefore, when the H/U ratio varies, the variation rate of the thermal utilization factor f becomes high. Accordingly, as shown by broken lines in FIG. 5, the thermal utilization factor f' of natural uranium tends to lower along a rightwardly-lowering inclined line of a large angle of inclination, and a maximum value of the infinite multiplication factor K.sub..infin. ' thereof is shifted to left, as compared with those of a regular enriched fuel. In view of the above, it is considered that the natural uranium is put in an excessively-moderated state in a regular operation region, and that, when the H/U ratio has increased, the infinite multification factor decreases. Due to the above described nuclear characteristics of natural uranium, extending the large central water rod 5A up to a position which corresponds to the natural uranium blanket region of a fuel rod causes the core reactivity to be slightly lost. Hence, as shown in FIG. 4, the height of the upper end of the large central water rod 5A is determined. This enables the length of the water rod to be reduced to a level within a range, which does not disadvantageously affect the nuclear characteristics of a fuel, and a pressure loss to be minimized. In the two embodiments described above, a large central water rod is employed according to the present invention. The effect of the present invention can be satisfactorily be obtained not only in a fuel assembly which uses this large central water rod but also in a fuel assembly which has a water rod of the same diameter as that of a conventional water rod and to which the present invention is applied. According to the present invention, the pressure loss in a two-phase flow portion of a fuel can be reduced without disadvantageously affecting the economical efficiency of the fuel, and the stability of a nuclear reactor and the thermal margin thereof can be improved.
055442102	description	MODES FOR CARRYING OUT THE INVENTION Referring now to FIGS. 1 through 6B, pressure vessel apparatus constructed in accordance with the teachings of the present invention is designated by reference numeral 10. Apparatus 10 is a nuclear reactor pressure vessel for use in large size light water integrated reactor systems and it includes vessel main body 12, vessel top body 14, and vessel head 16. Apparatus 10 is positioned within the interior of a containment vessel 200 with base 18 extending below ground level and defining a sump 20 having cooling water 22 disposed therein. Vessel main body 12 rests on seismic base isolators 24 located between the vessel base and the vessel main body. Pressure vessel apparatus 10 defines a pressure vessel interior 26 within which is positioned a nuclear core 28. Suitable support structure 30 such as a core barrel supports nuclear core 28 above the joint 44 of the vessel main body. In the arrangement illustrated, the vessel bottom 32 is convex and contains lead, lead alloy or other material 34. As is conventional, a steam outlet line 36 is in communication with the pressure vessel interior. A water inlet line (not shown) is also employed to furnish feed water to the pressure vessel interior. The vessel main body is constructed of any suitable material such as cast iron or reinforced concrete and includes an outer peripheral wall 38 with internal lining 201 of stainless steel plate extending upwardly from the bottom 32. At the top thereof the outer peripheral wall 38 defines a vessel main body top opening 40. Vessel top body 14 has an outer peripheral wall 42 positioned on the outer peripheral wall 38 of the vessel main body, forming a joint 44 therebetween. Outer peripheral wall 42 defines a vessel top body bottom opening corresponding in size to and communicating with the vessel main body top opening 40. In the arrangement illustrated, vessel top body 14 is of multi-part construction, including a segment 46 having an outer periphery corresponding to that of the vessel main body and a segment 48 which is of reduced circumference. The lower end of segment 48 is of frusto-conical configuration and seats into a recess of like size and configuration at the top of segment 46. Any suitable material such as cast iron or reinforced concrete may be utilized in the construction of vessel top body 14. As illustrated, segment 48 may be formed of reinforced concrete and segment 46 may be formed from cast iron, with internal lining 201 of stainless steel. The outer peripheral walls of vessel main body 12 and vessel top body 14 define a plurality of spaced throughbores 50 extending from the top of vessel top body 14 through the bottom of vessel main body 12. Throughbores 50 extend vertically alongside and spaced from the pressure vessel interior. A plurality of double-ended tendons under tension extend through the throughbores 50 and are secured to the vessel main body and the vessel top body. The tendons, which are designated by reference numeral 52, are directly connected at the bottoms thereof to vessel main body 12 by fixed tendon anchors 54. At the upper ends thereof tendons 52 are connected to vessel top body 14 in three different ways. Some of the tendons 52 are directly connected to the vessel top body 14 by tendon anchors 56 (see FIG. 6B). Suitable means such as an internal thread connection (not shown) is preferably employed to adjust the degree of tension imparted to the tendons 52 operatively associated with tendon anchors 56. These tendons may be provided with couplings (not shown) located beneath the joint 44. With reference to FIG. 6A, some of the tendons 52 may be prestressed close to yield and have their upper ends connected to a dashpot or damper 58 while other of the tendons are slightly prestressed and attached to disc spring mounts 60. The amount of prestress, the number, spacing and proportion of tendons mounted directly, on disc springs, or on dampers is based on a precalculation readily performed by a person skilled in the art to result in the optimum desired response of the vessel top body to given or postulated loads applied thereto. The purpose of the tendons 52 is to carry the vessel pressure during normal service and also to absorb pressure surges which may occur within the pressure vessel interior, for example caused by explosions or the like. Most of the energy will be absorbed by tendons 52 which may stretch into the plastic range up to a certain per cent of their length, e.g. about 3 per cent but less than ultimate. The different mounts of the tendons 52 will limit the response to less than ultimate. Since the tendons 52 essentially provide the sole force (other than gravity) maintaining the vessel top body in place on the vessel main body, stretching or elongation of the tendons 52 will enable the vessel top body 14 to be momentarily displaced in an upward direction relative to the vessel main body 12 to absorb the energy of sufficient increased pressure. In most instances such pressure increases can be expected to be of very brief duration, resulting in the vessel top body 14 again moving downwardly into place on the vessel main body 12. FIG. 4A shows the vessel top body 14 in its normal position relative to vessel main body 12 at joint 44. Upon increase of vessel interior pressure to a sufficient value, the vessel top body 14 will move upwardly as shown in FIG. 4B. Also illustrated in FIG. 4B is a sacrificial weld 62 which has less capacity than the liner 201 and fractures to allow separation of the vessel top body from the vessel main body upon application of sufficient force. As may also be seen with reference to FIGS. 4A and 4B, protective sleeves 64 with thermal insulation 202, for example asbestos, are disposed about tendons 52 at the location of joint 44 to afford protection to the tendons during relative movement between the vessel top body and the vessel main body, for example, by isolating the tendons from contact by hot fluids escaping the pressure vessel interior. The sleeves may also serve as guide for the vessel top body during the separation from the main body. In the arrangement illustrated, the sleeves 64 incorporate two components 66 and 68 which telescope relative to one another, sleeve component 66 being attached to vessel top body 14 while the sleeve components 68 are connected to vessel main body 12 and allow relative movement with respect to the tendons. At joint 44, bellows 70, cut and welded from steel tubing or formed of bent steel sheet or the like, extend between the vessel main body and the vessel top body about the joint to form a seal about the joint. Thus, bellows 70 serves to prevent the escape of heated fluids from the apparatus even when pressure surges results in dislocation of the vessel top body upwardly from the vessel main body. Elongated reinforcement members in the form of wires, bands or cables 72 limit the degree of outward movement of the bellows as shown in FIG. 4B. A cushion 203 of metallic lead, or other suitable material, is provided inside the bellows for support during the prestressing of the bellow reinforcement members 72. A passageway 74 leading from the space between the bellows 70 and the vessel top body 14 is in communication with instrumentation 76 to monitor liner leak tightness pressure or other physical conditions. Channels 80 extend circumferentially about vessel main body 12 and vessel top body 14. Channels 80 accommodate elongated reinforcement elements in the form of continuously wound prestressing wire strands or bands 82 under tension in engagement with and extending about the outer peripheral walls 38, 42 and 48. These prestressed reinforcement elements 82 substantially contribute to the structural strength of the vessel main body and the vessel top body and contribute to the ability thereof to resist high pressure generated within the pressure vessel interior. Any "breathing" of the structure may occur if the main body is segmented only after the top body separates from the main body, and will be short lived or not occur at all because of the formidable reserve strength of the prestressed reinforcement elements 82. Vessel head 16 includes two dome-like steel shells 86, 88 having outwardly extending peripheral flanges. In the arrangement shown, a lead, aluminum, or other metallic filler 90 is disposed between shells 86, 88 to distribute forces. Double-ended, elongated tendons 92 extend through spaced openings formed in the head flange comprised of the flanges of shells 86, 88 and extend downwardly to tendon coupling 93 located in throughbores 94 in the vessel top body 14 which are in registry with the openings in the head flanges. The lower ends of tendon couplings 93 are fixedly secured to the vessel top body 14 in any desired manner. The top ends of the tendons 92 are connected to the head shell 86 by head tendon stud anchors 96 which are preferably adjustable to control the degree of tension imparted to tendons 92. An important feature of the present invention resides in the fact that the tendons 52 secured to the vessel main body and the vessel top body permit movement of the vessel top body away from the vessel main body due to a pressure surge within the pressure vessel interior before the tendons secured to the vessel top body and the vessel top head permit movement of the vessel top head away from the vessel top body due to a pressure surge within the pressure vessel interior. As is conventional, the vessel head 16 supports control rod stand pipes 98, drive mechanism, shafts and housings, and various instrumentation which pass through openings in the vessel head (not shown) and extend to the nuclear core 28. FIG. 3 depicts a cross-section of the symmetric core with fuel-bundles within the pressure vessel interior 26. In the interest of simplicity, FIG. 1 only shows the upper portions of two control rod stand pipes 98. Momentary lifting of the vessel top body 14 (and thus vessel head 16) from vessel main body 12 as a result of high pressures within the pressure vessel interior will not cause relative movement between the control rods and the nuclear core because the support structure 30 supporting the nuclear core is itself supported by the vessel top body and will move upwardly therewith. The use of wire strand tendons to hold the vessel head to the vessel top body is a considerable improvement over the conventional threaded studs which have a lower strength capacity and ductility than the tendon studs which are normally at least partially comprised of wire strands. This permits a larger diameter and pressure load on the vessel head, and reduces stress and allows more room for control rods or other penetrations. With the present arrangement, all tension anywhere in the apparatus is carried or assumed by high-tensile wires or bands. The vessel main body, the vessel top body and most of the vessel head are under compression, with the apparatus itself in a state of three dimensional compression. FIG. 7 discloses an alternative form of the apparatus, identified by reference numeral 10A which is essentially of the same construction as apparatus 10 except that it employs a core catcher 100 containing lead or lead alloy for receiving core material and dissipating the decay heat in case of an accident.
	summary
	summary
	description	The present application claims priority from Japanese application serial no. 2007-092862, filed on Mar. 30, 2007, the content of which is hereby incorporated by reference into this application. The present invention relates to a control rod, and more particularly, to a control rod ideally applicable for a boiling water reactor to control reactor power. The structure of conventional control rods used in a boiling water reactor and installation environments will be described. The boiling water reactor is equipped with a reactor core, which is loaded with a plurality of fuel assemblies, in the reactor pressure vessel. Uranium 235 contained in nuclear fuel material included in the fuel assemblies absorbs neutrons and generates nuclear fission, thereby generating heat. Reactor water (cooling water) supplied in the core is heated by the heat and boils, and some part of the water turns into steam. In the core, neutrons newly generated by the above-mentioned nuclear fission cause another uranium 235 to fission, thereby generating a chain reaction. To control the amount of chain reactions of nuclear fission, control rods including neutron absorbers therein are utilized. Among those, a control rod normally used in a boiling water reactor has a crucial cross-section and is inserted into a gap (saturated water area) formed among each channel box contained in four fuel assemblies. One control rod is disposed per cell including four fuel assemblies. A control rod guide tube is disposed below the four fuel assemblies for almost each cell. The control rod guide tube is disposed in the reactor pressure vessel. One control rod uses each channel box contained in four fuel assemblies in a cell and the control rod guide tube as guide members. Furthermore, the lower end portion of the control rod is connected to a control rod drive mechanism, and the control rod is inserted into the reactor core by the operation of the control rod drive mechanism and then withdrawn from the reactor core. The control rod is an important device used for controlling reactivity and regulating power distribution. The structure of the conventional control rod used in the boiling water reactor will be described briefly. The control rod has a handle, a tie-rod, a fall velocity limiter and four blades. The handle is welded to an upper end portion of the tie-rod. The fall velocity limiter is welded to a lower end portion of the tie-rod. The four blades extend in four directions from the tie-rod located in the central axis of the control rod. Each blade has a U-shaped sheath mounted to the tie-rod, and a plurality of neutron absorbing rods that contain neutron absorbers are disposed inside the sheath (see Japanese Patent Laid-open No. 2002-257968). Japanese Patent Laid-open No. 2002-257968 further describes that a plurality of projecting portions are formed on the end face of the sheath in the axial direction of the sheath, and those projecting portions are welded to the tie-rod by laser welding. By providing projecting portions, the sheath is intermittently welded to the tie-rod in the axial direction. Furthermore, another well-known control rod is structured such that a hafnium plate, instead of a neutron absorbing rod, is disposed in the U-shaped sheath welded to the tie-rod (see Japanese Patent Laid-open No. Hei 8 (1996)-105989 and Japanese Patent Laid-open No. 2006-153522). However, recently, phenomena have been reported in that micro cracks occurred in the sheath of the control rod used in a boiling water reactor. If a crack occurred in the sheath lengthens toward the tie-rod, there is a possibility that the crack may reach into the tie-rod which is an axis of the control rod located at the center of the control rod and a very important member with respect to the strength. The generation of crack in the tie-rod must be avoided. It is an object of the present invention to provide a control rod which can prevent a tie-rod from cracking. The present invention for attaining the above object is characterized in that among a plurality of weld portions between a tie-rod and a sheath, an upper end of the weld portion located at an uppermost position in the axial direction of the tie-rod is disposed at a position within the range between 0.8 and 13% of total axial length Ls of the sheath below an upper end of the sheath. Because the upper end of the weld portion located at the uppermost position is disposed at a position within the range between 0.8 and 13% of the total axial length Ls of the sheath below the upper end of the sheath, in case a crack that has occurred at a location in which tensile residual stress in the upper end portion of the sheath becomes maximum lengthens in the direction perpendicular to the axial core of the tie-rod, the crack reaches the tie-rod-side end face of the sheath above the upper end of the weld portion located at the uppermost position. That is, that crack will not reach the weld portion located at the uppermost position. Therefore, it is possible to prevent a tie-rod from cracking resulting from a crack occurred in the sheath. It is preferable that the upper end of the above-mentioned weld portion located at the uppermost position is disposed at a position within the range between 4 and 13% of the total axial length Ls of the sheath below the upper end of the sheath. According to the present invention, it is possible to prevent a tie-rod used in the control rod from cracking. Inventors found out the cause of a crack that occur in a sheath of a control rod and newly invented a structure of a control rod which can prevent the crack from reaching into a tie-rod. The cause of the crack the inventors found out will be described below. A conventional control rod used in a boiling water reactor has a crucial cross-section and is equipped with four blades 2 extending in four directions from a tie-rod 4 as shown in FIGS. 4A and 4B. A handle 5 is fixed on an upper end portion of the tie-rod 4. A sheath 6 has a U-shaped cross-section, and a plurality of tabs 13 are formed on an end portion of the sheath 6 in an axial direction of the sheath 6. Those tabs 13 are welded to the tie-rod 4. An upper end portion of the sheath 6 is welded to the handle 5. Number 14 denotes a weld portion between the tab 13 and the tie-rod 4, and number 15 denotes a weld portion between the sheath 6 and the handle 5. A hafnium member 3 being a neutron absorber is disposed in the sheath 6 and mounted to the handle 5. A plurality of apertures 12 which introduce a coolant inside are formed on the sheath 6. Recently, phenomena have been reported in that micro crack occurred in the sheath of the control rod used in a boiling water reactor (BWR). This crack 21 occur in the vicinity of the weld portion 15 as shown in FIG. 4A. The inventors investigated the cause of the crack 21. The results will be described below. It is considered that the crack 21 is an irradiation-assisted stress corrosion cracking (IASCC) which occurs when three factors of stress, corrosion, and radiation are superimposed at the same time. In the vicinity of the weld portion 15, a narrow gap is formed between the hafnium member and the sheath wherein the above three factors exist, which creates an environment in which the crack tends to occur. The inventors investigated a stress distribution in the vicinity of the weld portion 15 and found out that the tensile residual stress resulting from the welding to join a handle 5 and a sheath 6 in the upper end portion of the sheath 6 has been increased (see FIG. 4C). The inventors considered that the crack 21 occurred in the upper end portion of the sheath 6 due to the influence of the tensile residual stress. Specifically, the investigation of the location of the crack 21 revealed that the crack 21 concentrated at a position 17 where tensile residual stress is maximum (see FIG. 4C). Because a tensile force resulting from tensile residual stress operates in the direction of the double headed arrow 16 (the axial direction of the tie-rod 4), as shown in FIGS. 1A, 4A and 5A, the crack 21 lengthens in the direction perpendicular to the axial core of the tie-rod 4. However, even if this crack 21 occurs, the soundness of the control rod is not affected. This conclusion is brought by the fracture mechanics assessment which indicates that the growth of the crack 21 stops before they reach the tie-rod 4 due to the influence of the compressive residual stress that intermittently occurs in the weld portion 14 in the axial direction. Furthermore, an IASCC can be avoided by eliminating one of three factors, which are stress, corrosion, and irradiation; for example, by eliminating tensile residual stress. Generally, there is a method for reducing tensile residual stress by applying thermal treatment after the welding. However, it is difficult to apply this method to a control rod because of its structure, and the thermal treatment of the control rod causes a dimension error to occur. Therefore, it is difficult to apply this method to a control rod which is subject to strict dimension tolerance. As stated above, even if the crack 21 occur in the upper end portion of the sheath 6, there is no possibility that the crack 21 lengthens into the tie-rod 4 due to the influence of compressive residual stress in the weld portion 14. However, to increase the safety of the control rod, the inventors invented a structure of a control rod which unfailingly stops the growth of the cracks 21 into the tie-rod 4. That is, the inventors invented a structure in which a weld portion 14 located at the uppermost position is located below the position 17 at which tensile residual stress is maximum based on the characteristics of the stress distribution in the upper end portion of the sheath 6 shown in FIG. 4C. As the result of the investigation of the crack 21 occurred in the upper end portion of the sheath 6, this crack 21, which is present at the lowermost position within the range of the position 17, is occurring at a position 0.75% of the total length of the sheath 6 in the axial direction of the sheath 6 below the upper end of the sheath 6. For this reason, in view of the safety, the inventors invented a structure in which the upper end of the weld portion located at the uppermost position among a plurality of weld portions between the tie-rod and the sheath is disposed at a position within the range between 0.8 and 13% of the total axial length of the sheath below the upper end of the sheath in the axial direction of the tie-rod. In other words, the upper end of the tab (projecting portion), welded to the tie-rod, located at the uppermost position is disposed at a position within the range between 0.8 and 13% of the total axial length of the sheath below the upper end of the sheath. In the case in which the upper end of the above-mentioned weld portion located at the uppermost position is located at a position of 0.8% or more of the total axial length of the sheath below the upper end of the sheath in the axial direction of the tie-rod, even if crack 21 that occurred in the upper end portion of the sheath 6 lengthens in the direction perpendicular to the axial core of the tie-rod 4, the crack 21 will not reach the weld portion 14 connected to the tie-rod 4. Therefore, it is possible to unfailingly prevent the tie-rod 4 from cracking as the result of the growth of the crack 21. Furthermore, since the upper end of the above-mentioned weld portion located at the uppermost position is located 13% of the total axial length of the sheath, at a maximum, below the upper end of the sheath in the axial direction of the tie-rod, it is possible to satisfy the strength of the sheath required with regard to the earthquake-resistance. In the case in which the upper end of the above-mentioned weld portion located at the uppermost position is located at a position more than 13% of the total axial length of the sheath below the upper end of the sheath in the axial direction of the tie-rod, it is not possible to ensure the required earthquake-resistance capacity. Embodiments of a control rod configured as mentioned above will be described below. A control rod according to embodiment 1 which is a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 3. A control rod 1 in the present embodiment is used in a boiling water reactor. The control rod 1 has a crucial cross-section. The control rod 1 is provided with a tie-rod 4 disposed in the axial core of the control rod 1, and four blades 2 extend in four directions from the tie-rod 4. A handle 5 is fixed to an upper end portion of the tie-rod 4, and a connector plate 8 is fixed to a lower end portion of the tie-rod 4. Rollers 18 are rotatably mounted to the connector plate 8. The roller 18 comes in contact with the outer surface of a channel box of a fuel assembly loaded in the core, and the roller 18 functions to allow the control rod 1 to move smoothly among the fuel assemblies. Each blade 2 includes a sheath 6 having the cross-section of which is U-shaped and hafnium members 3U,3L which are flat tubes (see FIG. 3). The sheath 6 is made of stainless steel (SUS304 and SUS316L, or the like). An upper end of the sheath 6 is welded to the handle 5, a lower end of the sheath 6 in the axial direction of the tie-rod 4 is welded to the connector plate connector plate 8. A plurality of tabs (projecting portions) 13 are formed on both U-shaped end portions of the sheath 6 in its axial direction with predetermined intervals. The tabs 13 are a part of the sheath 6 which protrude toward the tie-rod 4. Those tabs 13 are welded to the tie-rod 4 to form weld portions 14 (see FIG. 1A). The weld portion 14 is formed along the total length of the tab 13 in the axial direction of the tie-rod 4. The length of the weld portion 14 in the axial direction of the tie-rod 4 can be shorter than the total length of the tab 13. A plurality of apertures 12 are formed by penetrating the sheath 6. The connections between the sheath 6 and the tie-rod 4, handle 5, and the connector plate 8 are made, for example, by laser welding. Two hafnium members 3U and two hafnium members 3L are disposed in a space formed inside the sheath 6. The hafnium members 3U are located above the hafnium members 3L. Upper end portions of the hafnium members 3U are mounted to the handle 5, and the hafnium members 3L are mounted to the connector plate 8. Those hafnium members are neutron absorbing members. The gap located between a lower end of the hafnium member 3U and an upper end of the hafnium member 3L is of a minimum width within the range in which the hafnium members do not come in contact with each other when the hafnium members 3U,3L become thermally-expanded while the boiling water reactor is in operation. In FIG. 2, Ls denotes total axial length of the sheath 6, and Lc denotes effective length of the neutron absorber of the control rod 1 (the length from the lower end of the hafnium member 3L to the upper end of the hafnium member 3U). Control rods 1 are disposed in the reactor pressure vessel of a boiling water reactor and inserted into and withdrawn from a core loaded with a plurality of fuel assemblies so as to control reactor power. The control rod 1 is connected to a control rod drive mechanism disposed at the bottom of the reactor pressure vessel by a connector 19 located in the lower end portion of the connector plate 8. The control rod drive mechanism operates to insert a control rod 1 into the core and withdraw the control rod 1 from the core. Cooling water flowing in the reactor pressure vessel flows into the sheath 6 through some apertures 12 to cool the hafnium members 3U,3L and then flows out from the sheath 6 from other apertures 12. Cooling water flowing into the sheath 6 flows into the hafnium members 3U through an aperture 10 having a small diameter provided in the hafnium members 3U, and then flows into the hafnium members 3L through an aperture 11 having a small diameter provided in the hafnium members 3L. Thus, as the result of the inflow of the cooling water into the hafnium members 3U,3L, cooling effects of the hafnium members are increased. The distribution of residual stress that occurs around the upper end portion of the sheath 6 due to the welding between the handle 5 and the sheath 6 is as shown in FIG. 1C. Tensile residual stress occurs near the weld portion 15. In the axial direction of the tie-rod 4, compressive residual stress occurs at a position downwardly away from the position 17 at which tensile residual stress is maximum. A crack 21 occurs at the position 17 at which tensile residual stress is maximum. In the control rod 1 of the present embodiment, the tab 13 (specifically, an upper end of the tab 13) located at the uppermost position in the axial direction of the tie-rod 4, in other words, the weld portion 14 (specifically, an upper end of the weld portion 14) located at the uppermost position is located below the position 17 at which tensile residual stress is maximum as shown in FIG. 1A. That is, the upper end of the tab 13 located at the uppermost position is disposed at a position within the range between 0.8 and 13% of the total axial length Ls of the sheath 6 in the axial direction of the tie-rod 4 below the upper end of the sheath 6. For example, in the control rod 1, the tab 13 located at the uppermost position, that is, the upper end of the weld portion 14 is located at a position 2.0% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6 in the axial direction of the tie-rod. In the control rod 1, since the tab 13 located at the uppermost position is disposed as mentioned above, even if a crack 21 that occurred within the position 17 in the sheath 6 lengthens in the direction perpendicular to the axial core of the tie-rod 4, the crack 21 reaches the end face of the sheath 6 in the direction perpendicular to the axial core of the tie-rod 4 at a position upwardly away from the weld portion 14. That is, even if the crack 21 advances in the direction perpendicular to the axial core of the tie-rod 4, the crack will not reach the weld portion 14. Therefore, it is possible for the control rod 1 to prevent the tie-rod 4 from cracking resulting from the crack 21 that occurred in the sheath 6. The present embodiment is capable of significantly increasing the safety of the tie-rod 4, thereby increasing the safety of the control rod 1 significantly. A control rod according to embodiment 2 which is another embodiment of the present invention will be described with reference to FIG. 5. In the control rod 1A of the present embodiment, the position of the tab located at the uppermost position is different from that of the control rod 1, but other structures of the control rod 1A are the same as those of the control rod 1. In a control rod 1A of the present embodiment, the tab 13A (specifically, the upper end of the tab 13A) located at the uppermost position in the axial direction of the tie-rod 4, in other words, the weld portion 14 (specifically, the upper end of the tab 13A) located at the uppermost position is disposed at a position at which residual stress is not tensile residual stress as shown in FIG. 5A. With regard to residual stress that occurs in the sheath 6, tensile residual stress disappears at a position 4% of the total axial length of the sheath 6 below the upper end of the sheath 6. At a position 4% or more below the upper end of the sheath 6, residual stress becomes compressive residual stress. Based on these results, in the control rod 1A, the upper end of the tab 13A located at the uppermost position is disposed at a position within the range between 4 and 13% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6 in the axial direction of the tie-rod 4. For example, in the control rod 1A, the tab 13A located at the uppermost position, that is, the upper end of the weld portion 14 is located at a position 10% of the total axial length Ls below the upper end of the sheath 6 in the axial direction of the tie-rod 4. In the control rod 1A, since the tab 13A located at the uppermost position is disposed as mentioned above, this tab 13A is disposed at a position where compressive residual stress occurs in the axial direction of the sheath 6. For this reason, even if a crack 21 that occurred within the position 17 in the sheath 6 lengthens in the direction perpendicular to the axial core of the tie-rod 4, the crack 21 reaches the end face of the sheath 6 in the direction perpendicular to the axial core of the tie-rod 4 at a position upwardly away from the weld portion 14. That is, even if the crack 21 lengthens in the direction perpendicular to the axial core of the tie-rod 4, the crack will not reach the weld portion 14. Therefore, it is possible for the control rod 1A to prevent the tie-rod 4 from cracking resulting from the crack 21 that occurred in the sheath 6. The present embodiment is capable of significantly increasing the safety of the tie-rod 4, thereby increasing the safety of the control rod 1A significantly. A control rod according to embodiment 3 which is another embodiment of the present invention will be described with reference to FIG. 6. In the control rod 1B of the present embodiment, the shape of the hafnium members and their installation structure are different from those of the control rod 1. Other structures of the control rod 1B are the same as those of the control rod 1. The difference between the control rod 1B and the control rod 1 will be described in detail. The control rod 1B also has a crucial cross-section. The control rod 1B is equipped with four blades extending in four directions 2A from the tie-rod 4. With regard to the blade 2A, eight pairs of plate-like hafnium members 3A, facing each other, are disposed in the axial direction inside the sheath 6 having a U-shaped cross-section. For example, a pair of hafnium members 3A that face each other are immobilized onto each of the side walls of the sheath 6 that face each other by immobilizing members 20. Four immobilizing members 20 are disposed by penetrating the vicinity of each of four corners of a pair of hafnium members 3A. A handle 5 is fixed to an upper end portion of the tie-rod 4, and the connector plate 8, not shown, is fixed to a lower end portion of the tie-rod 4. In the control rod 1B, a plurality of tabs (projecting portions) 13 are formed on both U-shaped end portions of the sheath 6 with predetermined intervals in the axial direction. Those tabs 13 are, for example, welded to the tie-rod 4 by laser welding. The sheath 6 is welded in the same manner as the control rod 1, and the handle 5 and the connector plate 8 are welded, for example, by laser welding. In the control rod 1B, the tab 13 located at the uppermost position, that is, the weld portion 14 located at the uppermost position (not shown in FIG. 5) is disposed at a position lower than the position 17 at which tensile residual stress is maximum as in the same manner as embodiment 1. That is, the tab 13 located at the uppermost position is disposed at a position within the range between 0.8 and 13% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6 in the axial direction of the tie-rod 4. For example, in the control rod 1B, the tab 13 located at the uppermost position, that is, the upper end of the weld portion 14 is disposed at a position 2.0% of the total axial length Ls below the upper end of the sheath 6 in the axial direction of the tie-rod. In the control rod 1B, even if a crack 21 that occurred within the position 17 in the sheath 6 lengthens in the direction perpendicular to the axial core of the tie-rod 4, it is possible for the control rod 1B to prevent the tie-rod 4 from cracking in the same manner as the control rod 1. The safety of the control rod 1B is significantly increased. In the control rod 1B, in the same manner as embodiment 2, it is possible to dispose the tab 13 located at the uppermost position, that is, the weld portion 14 at a position within the range between 4 and 13% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6 in the axial direction of the tie-rod 4. A control rod according to embodiment 4 which is another embodiment of the present invention will be described. In a control rod 1 according to embodiment 1, since the weld portion 14 located at the uppermost position is downwardly away from the weld portion 15 further than the position in the conventional control rod, there is a possibility that the position 17 at which tensile residual stress is maximum may also move downward. To avoid this phenomenon, it is possible to locate the position 17 at which tensile residual stress is maximum close to the weld portion 15 by controlling quantity of heat absorbed at the time of welding of the weld portion 15 between the handle 5 and the sheath 6. That is, by increasing quantity of heat absorbed of the weld portion 15 up to quantity of heat absorbed which is more than 100% of that of the weld portion 14 and 300% or less of it, it is possible to locate the position at a position 17 above a position 0.8% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6. For this reason, by disposing the tab 13 located at the uppermost position at a position 0.8% of the total axial length Ls of the sheath 6 below the upper end of the sheath 6 in the axial direction of the tie-rod 4, even if a crack that occurred at the position 17 at which tensile residual stress is maximum in the sheath 6 lengthens toward the tie-rod 4, it is possible to prevent the tie-rod 4 from cracking in the same manner as embodiment 1. The method to make quantity of heat absorbed of the weld portion 15 smaller than 300% of quantity of heat absorbed of the weld portion 14 can be applied to each control rod in embodiment 2 and embodiment 3. Furthermore, in a control rod in which a fall velocity limiter is mounted to the lower end portion of the tie-rod 4 instead of using a connector plate 8, it is possible to dispose the tab located at the uppermost position in the same manner as the control rod 1 and the control rod 1A. In this case, the lower end of the sheath is welded to the fall velocity limiter.
	description	This is a §371 of International Application No. PCT/EP2007/005919, with an international filing date of Jul. 4, 2007 (WO 2008/003476 A2, published Jan. 10, 2008), which is based on European Patent Application No. 06013850.0 filed Jul. 4, 2006. The invention relates to an imaging apparatus, particularly to a tomography apparatus, and to a corresponding imaging method. Tomography apparatuses are well known and widely used in the fields of medical science and materials research as a diagnostic tool for generating sectional views of an object, e.g. the human body. The conventional tomography apparatuses comprise a radiation source, e.g. an X-ray source, rotating relative to the object and transmitting radiation through the object at different angles. Further, a radiation detector is disposed on the other side of the object for detecting the radiation after transmission through the object. In conventional tomography apparatuses the radiation detector comprises a large number of picture elements in order to achieve a high optical resolution. In this way, so-called Radon data are generated, which are representing properties (e.g. the attenuation of the radiation) of the object and which are further processed for generating a cross sectional view of the object. The general principles of computer tomography are explained in, for example, BUZUG: “Einführung in die Computertomographie”, Springer-Verlag (2004). One problem of the aforementioned conventional tomography apparatuses is that the optical resolution is restricted by the number and size of the picture elements of the radiation detector. On the one hand, a large number and a small size of the picture elements are desirable in order to obtain a high optical resolution of the tomography apparatus. On the other hand, radiation detectors having a large number of picture elements are quite expensive and require a high dose for a sufficient signal to noise ratio (SNR). It is therefore desirable to improve the aforementioned conventional tomography apparatuses, so that a high optical resolution is achieved with low costs of the radiation detector. This is achieved by an imaging apparatus and an imaging method according to the following. An example provides an imaging apparatus, particularly a tomography apparatus, for analysing an object comprising a radiation source for transmission of radiation through the object in a section plane of the object and further comprising a radiation detector for detecting the radiation in the section plane of the object after transmission through the object. Further, the imaging apparatus comprises a masking device for masking out a part of the radiation, wherein the masked part of the radiation is movable in the section plane relatively to the radiation detector during the analysis of the object. The Radon data are calculated from the differences of the detector output during the movement of the masked part of the radiation. Therefore, it is not necessary to provide a multi-channel radiation detector having a large number of picture elements in order to achieve a high optical resolution. Instead, a high optical resolution is achieved by moving the masked part of the radiation relatively to the detector, so that the data generated by the radiation detector are representative of a specific angle as in the conventional radiation detectors having a large number of picture elements. Hence, the optical resolution of the imaging apparatus is determined by the motion speed of the masked part of the radiation and the sampling rate of the measurements of the radiation detector. The lower the motion speed of the masked part of the radiation and the higher the time resolution of the radiation detector, the higher is the optical resolution, which can be achieved by the imaging apparatus. It is therefore advantageously possible to achieve an extremely high optical resolution with a low cost radiation detector. In an exemplary embodiment of the invention, a masking device comprises a movable shutter being disposed in a path of the radiation between a radiation source and a radiation detector, so that the shutter is blocking, i.e. shielding, a part of the radiation depending on its position. In this embodiment, the shutter is an opto-mechanical component, which is intransparent with regard to the radiation and which can be moved relatively to the detector. In a first variant of this embodiment the shutter is disposed between the radiation source and the object. However, it is alternatively possible to dispose the shutter between the object and the radiation detector, i.e. on the other side of the object. Further, the shutter can be linearly or rotary movable. In case of a rotary shutter, the shutter is preferably cylindrical and surrounding the object or the radiation source, wherein the object is preferably disposed on the axis of rotation of the shutter. Moreover, the shutter is preferably a single-edge shutter blocking the radiation in the section plane on one side only. However, it is theoretically possible to use a slot shutter having a slot, wherein the slot shutter is blocking the radiation on both sides of the slot. Further, the imaging apparatus preferably comprises a drive for moving the shutter with a defined motion speed and a feedback controller for closed loop controlling of the motion speed of the shutter depending on the output of the radiation detector. If the output of the radiation detector indicates a detail within the object, the feedback controller preferably reduces the motion speed of the shutter, so that the optical resolution is increased at the position of the detail within the object. However, if the output of the radiation detector indicates a homogeneous part of the object, the feedback controller preferably increases the motion speed of the shutter, since a high optical resolution is not necessary in homogeneous parts of the object. In another embodiment of the invention, the masking device does not comprise an opto-mechanical shutter. Instead, the masking device is making the radiation detector partially insensitive in order to mask out a corresponding part of the radiation. In this embodiment the masking device and the radiation detector can be integrated in a single component thereby reducing the complexity and the costs of the imaging apparatus according to the invention. For example, a multi-channel radiation detector might be used having several picture elements, which are selectively deactivated in order to mask out a part of the radiation in the region of the deactivated picture elements. It has already been mentioned that the masked part of the radiation, i.e. the blocked or shielded part of the radiation, is movable relatively to the radiation detector. In one embodiment of the invention the radiation detector is fixedly arranged, whereas the masked part of the radiation is movable, e.g. by moving the aforementioned opto-mechanical shutter. In another embodiment of the invention, the masked part of the radiation is fixedly arranged, e.g. due to a stationary shutter, whereas the radiation detector is movable, e.g. by rotating the radiation detector around the object. However, it is also possible that both the radiation detector and the masked part of the radiation are being moved during the analysis of the object, e.g. by moving both the radiation detector and the shutter. The radiation detector preferably comprises a single output channel, so that an inexpensive radiation detector can be used. However, it is alternatively possible to use a radiation detector having multiple (e.g. five) output channels, wherein the masking device is used to increase the optical resolution. Further, it should be noted that the object itself is preferably rotating during the analysis. Therefore, the imaging apparatus preferably comprises a rotary carrier receiving the object, wherein the rotary carrier has an axis of rotation, which is aligned perpendicular to the section plane through the object. Further, the imaging apparatus preferably comprises a drive for rotating the carrier along with the object around the axis of rotation, whereas the radiation detector is preferably fixed. The object is preferably rotated in order to generate the aforementioned so-called Radon data. However, it is alternatively possible to rotate the radiation detector. In other words, a relative movement is necessary. Moreover, it should be noted that the radiation source is not necessarily an X-ray source as initially mentioned. Instead, the radiation source can be an ultrasonic source, a light source, particularly a laser, a Gamma radiation source, a neutron source, an electron source, a radiation source emitting electromagnetic waves, particularly microwaves, or a radiation source emitting ionising or non-ionising radiation. In other words, the imaging apparatus is not restricted to a specific type of radiation. Further, the imaging apparatus preferably comprises an evaluation unit connected to the radiation detector for generating Radon data from the detected radiation, wherein the Radon data are representing properties of the object, so that a sectional view of the object can be generated by processing the Radon data. However, the evaluation unit is not necessarily part of the invention, so that the imaging apparatus can be realized as a separate system delivering imaging data to the evaluation unit, which is a separate system. The further processing of the Radon data can be accomplished in a conventional way, which is disclosed for example in BUZUG: “Einführung in die Computertomographie”, Springer-Verlag (2004). Therefore, the disclosure of the aforementioned reference book is incorporated by reference herein with regard to the generation and further processing of the Radon data. It should further be noted that the invention is not restricted to the aforementioned imaging apparatus but also relates to a corresponding imaging method. Further, the invention is not restricted to the use as a diagnostic tool in the field of medical science. Further, the imaging apparatus can also be used for analysing mechanical components of a machine, particularly of a spacecraft or an aircraft. FIGS. 1A and 1B schematically show a presently preferred embodiment of a tomography apparatus 1 according to the invention. The tomography apparatus 1 comprises a radiation source 2 emitting radiation 3 in a section plane in the direction of an object 4, e.g. a human body, wherein the section plane is identical with the plane of the drawing. However, the invention is not restricted to the analysis of the human body. Instead, other types of objects can be analysed, e.g. mechanical parts of machines, particularly of aircrafts or spacecrafts. In this embodiment the radiation source 2 is an X-ray source. However, other types of radiation sources can be used within the framework of the invention. Further, the tomography apparatus 1 comprises a radiation detector 5, which is disposed in the path of the radiation 3 behind the object 4, so that the radiation detector 5 detects the radiation 3 after transmission through the object 4. Further, it should be noted that the radiation detector 5 comprises a single output channel 6 only, so that the radiation detector 5 is quite inexpensive compared with multi-channel radiation detectors as used in conventional tomography apparatuses. Further, the tomography apparatus 1 comprises an opto-mechanical shutter 7, which is disposed in the path of the radiation 3 between the object 4 and the radiation detector 5. The shutter 7 is linearly movable by a motor 8, so that the shutter 7 is masking out a part of the radiation 3 depending on the position s of the shutter 7 relative to the radiation detector 5. It should further be noted that the object 4 is disposed on a rotary carrier 9, which is rotatable around an axis of rotation, which is aligned perpendicular to the section plane of the object 4, i.e. the plane of the drawing. Further, the tomography apparatus 1 comprises a motor 10, which is rotating the rotary carrier 9 along with the object 4 during the analysis of the object. The radiation detector 5 detects an intensity D of a part the radiation 3, which is transmitted through the object 4 and not blocked by the opto-mechanical shutter 7. Therefore, the intensity D of the detected radiation 3 depends both on the position s of the shutter 7 and the properties of the object 4, i.e. the attenuation of the radiation 3 by the object 4. In case of in idealised fully homogeneous object 4, the intensity D is approximately linearly dependent on the position s of the opto-mechanical shutter 7 as shown by the dashed line in FIG. 2. However, if the object 4 is inhomogeneous, as in the case of a human body, the intensity D is not only dependent on the position s of the opto-mechanical shutter 7, but also depends on optical properties of the object 4. Therefore, the inclination of the curve as shown in FIG. 2 depends on local variations of the optical properties of the object 4. Therefore, the single output channel 6 of the radiation detector 5 is connected to a differentiator 11, which calculates the derivative dD/ds of the intensity D with regard to the position s of the shutter 7, since this derivative is indicative of the optical properties of the object 4. Further, the differentiator 11 is connected to an evaluation unit 12, which generates conventional Radon data for further processing as known in the state of the art. Moreover, the differentiator 11 is connected to a controller 13, which actuates a driver 14. The driver 14 in turn actuates the motor 8, which moves the shutter 7. Therefore, the controller 13 controls the motion speed ds/dt of the opto-mechanical shutter 7 depending on the derivative dD/ds, so that the motion speed of the shutter 7 is closed loop controlled by the controller 13. If the output of the radiation detector 5 indicates a detail within the object 4, the feedback controller 13 preferably reduces the motion speed ds/dt of the shutter 7, so that the optical resolution is increased at the position of the detail within the object 4. However, if the output of the radiation detector 5 indicates a homogeneous part of the object 4, the feedback controller 13 preferably increases the motion speed ds/dt of the shutter 7, since a high optical resolution is not necessary in homogeneous parts of the object 4. The afore-mentioned tomography apparatus 1 allows several modes of operation, which will be explained in the following. In a first mode of operation, the shutter 7 is moved discontinuously, i.e. step-by-step, and the radiation detector 5 is resetted after each step. In a second mode of operation, the shutter 7 is moved continuously and the radiation detector is resetted periodically. In a third mode of operation, the radiation detector 5 is not resetted during the analysis of the object 4. Further, the shutter 7 can be moved either discontinuously, i.e. step-by-step, or continuously. However, in this mode of operation the differentiator 11 must differentiate the measured intensity D with regard to time t and with regard to the position s of the shutter 7. FIGS. 3A and 3B schematically show a similar tomography apparatus 1, which partially corresponds to the tomography apparatus 1 as shown in FIGS. 1A and 1B. Therefore, it is referred to the above description in order to avoid unnecessary repetitions. Further, the same reference numerals are used in the following description relating to the embodiment according to FIGS. 3A and 3B. One major difference of this embodiment is that the shutter 7 is rotary movable and approximately pot-shaped. Therefore, the shutter 7 is partially blocking the radiation 3 depending on its angularity α. FIGS. 4A and 4B schematically show another embodiment of a tomography apparatus 1 according to the invention, which is similar to the embodiment shown in FIGS. 1A and 1B. Therefore, reference is made to the above description in order to avoid unnecessary repetitions. Further, the same reference numerals are used in the following description. One major difference of this embodiment is that the shutter 7 is disposed in the path of the radiation 3 between the radiations source 2 and the object 4. Finally, FIG. 5 schematically shows another embodiment of the invention. This embodiment also comprises a rotary carrier 14 receiving in object 15, e.g. a human body, which is to be analysed. The rotary carrier 14 along with the object 15 is rotated around an axis of rotation being aligned perpendicular to the plane of the drawing. Further, the tomography apparatus comprises a radiation source 16 emitting radiation 17 in the direction of the object 15 so that the radiation 17 is transmitted through and attenuated by the object 15. Moreover, in this embodiment the tomography apparatus comprises a pot-shaped radiation detector consisting of five separate radiation detectors 18-22 surrounding the object 15. The radiation detectors 18-22 are rotating around the same axis of rotation as the rotary carrier 14 and in the same direction. However, the radiation detectors 18-22 are rotating with a rotational speed ω1, whereas the rotary carrier 14 is rotating with a rotational speed ω2=0.5ω1. Further, the inner circumferential surface of the pot-shaped detectors 18-22 is partially shielded by a stationary shutter 23. While one or more specific preferred embodiments have been described herein, those skilled in the art will readily recognize modifications, variations and examples that do not depart from the spirit and scope of the subject invention, as herein claimed.
	summary
043303706	claims	1. A combination seal and bearing arrangement for use in a nuclear reactor which includes a vertically extending vessel containing therein a number of components and a vessel cover located over the top of said vessel, said cover including first rotatable plug means which serves to perform certain position related functions on certain ones of said components and second means surrounding said plug means and, together with the latter, defining an annular opening therebetween, said combustion seal and bearing arrangement comprising: stationary means fixedly mounted with said surrounding means and extending around the outside of said annular opening, rotating mean fixedly mounted with said plug means for rotation therewith and extending around the inside of said annular opening, said rotating means together with said stationary means defining a circumferential path which extends outwardly from said annular opening to the ambient surroundings; bearing means located between and engaging said stationary and rotating means in said path; and a single sealing and lubricating liquid filling an entire circumferential section of said path between said bearing means and said annular opening for sealing said path from the influx of ambient elements at said section and, at the same time, for lubricating said bearing means. 2. An arrangement according to claim 1 wherein at least one of said stationary or rotating means includes passageway means extending between the ambient surroundings and said circumferential path section for filling said section with and draining said section of said sealing and lubricating liquid. 3. An arrangement according to claim 2 wherein said passageway means includes a passageway for filling said path section with said liquid and a separated passageway for draining said path section of said liquid. 4. An arrangement according to claim 1 including an inflatable and deflatable seal means supported by one of said stationary and rotating means and extending around a second circumferential section of said path between said bearing means and the ambient surroundings, said seal means engaging the other of said stationary and rotataing means when inflated for sealing said path at said section circumferential section and completely disengaging said other means when deflated. 5. An arrangement according to claim 4 wherein said one means supporting said inflatable and deflatable seal means includes separate disengagable means supporting said seal means whereby the latter can be readily replaced. 6. An arrangement according to claim 1 wherein one of said stationary and rotating means includes means defining an annular channel between said annular opening and said bearing means and opening upwardly, and wherein the other of said stationary and rotating means includes a main body and a downwardly extending annular flange supported by and spaced from said main body, said flange having a bottom end section which is located within said channel and which, together with the latter, define said circumferential path section, and wherein said sealing and lubricating liquid is a non-metallic liquid located within said channel around said flange end section. 7. An arrangement according to claim 6 wherein said one means defining said annular channel includes first and second passageways extending between said channel and the ambient surroundings for filling and draining said channel. 8. An arrangement according to claim 6 wherein said channel defining means defines a second upwardly opening annular channel in said leakage path and concentric with said first-mentioned channel between the latter and said annular opening, said second channel being provided for receiving any of said liquid which inadvertently splashes out of said first-mentioned channel in the direction of said annular opening, whereby to prevent said splashed liquid from reaching said opening. 9. An arrangement according to claim 8 wherein said one means defining said first-mentioned and second annular channels includes first and second passageways extending between said first-mentioned channel and the ambient surroundings for filling and draining said first-mentioned channel, respectively, and a third passageway extending between said second channel and the ambient surroundings for draining said second channel. 10. An arrangement according to claim 1 wherein one of said stationary and rotating means includes means defining an annular channel between said annular opening and said bearing means and opening upwardly, wherein the other of said stationary and rotating means includes a main body and a downwardly extending annular flange supported by and spaced from said main body, said flange having a bottom end section which is located within said channel and which, together with the latter, define said circumferential path section, wherein said sealing and lubricating liquid is a non-metallic liquid located within said channel around said flange end section, wherein said channel defining means defines a second upwardly opening annular channel in said path and concentric with said first-mentioned channel between the latter and said annular opening, said second channel being provided for receiving any of said liquid which inadvertently splashes out of said first-mentioned channel in the direction of said annular opening, whereby to prevent said splashed liquid from reaching said said opening, and wherein said one means defining said first-mentioned and second annular channels includes first and second passageways extending between said first-mentioned channel and the ambient surroundings for filling and draining said first-mentioned channel, respectively, and a third passageway extending between said second channel and the ambient surroundings for draining said second channel. 11. An arrangement according to claim 10 including an inflatable and deflatable seal means and separate disengagable means supporting said seal means to one of said stationary and rotating means and extending around a second circumferential section of said path between said bearing means and the ambient surroundings, said seal means engaging the other of said stationary and rotating means when inflated for sealing said path at said section circumferential section and completely disengaging said other means when deflated.
041773861	claims	1. A storage rack for spent nuclear fuel assemblies for immersion in water, said rack comprising a plurality of identical storage cells disposed adjacent each other in a regular array with adjacent cells connected together, cap members disposed on alternate cells and adapted to guide fuel assemblies into adjacent cells whereby the rack initially contains fuel assemblies in at least half of the storage cells, the remaining cells being filled with water, and at least some of said cap members being removable to permit fuel assemblies to be placed in additional cells in a final pattern determined by the actual level of reactivity of said fuel assemblies such that criticality is prevented. 2. A storage rack as defined in claim 1 in which said storage cells include a neutron-absorbing material. 3. A storage rack as defined in claim 1 in which said storage cells are made of stainless steel. 4. A storage rack as defined in claim 1 in which certain of said cap members are permanently attached to the cells, said permanently attached cap members being in positions in the array of cells which determine said final pattern. 5. A storage rack as defined in claim 1 in which the storage cells are of square cross section and aligned with each other to form a checkerboard array. 6. A storage rack as defined in claim 5 in which cap members are initially disposed on alternate storage cells in each row of cells, the cap members in adjacent rows being staggered with respect to each other. 7. A storage rack as defined in claim 6 in which certain of said cap members are permanently attached to the cells, said permanently attached cap members being on cells which define said final pattern.
	claims	1. In combination with a catalytic device including at least one of a catalytic recombination device and a catalytic ignition device, the catalytic device having a number of catalyst bodies with a predetermined catalytic surface, a device for initiating. a hydrogen/oxygen reaction in the catalytic device, comprising: an energy feed device connected to the catalytic device for introducing energy and permanently maintaining a portion of said predetermined catalytic surface at a temperature level above an ambient temperature, said portion being less than 5% of said predetermined catalytic surface. 2. The combination according to claim 1 , wherein said energy feed device comprises an electrical energy source electrically connected to an electrical heating device. claim 1 3. The combination according to claim 2 , wherein said electrical energy source comprises a local energy store. claim 2 4. The combination according to claim 3 , wherein said local energy store is a battery. claim 3 5. The combination according to claim 3 , wherein said energy feed device further comprises a central current supply device and a change-over switch connected to said current supply device and to said local energy store, and said switch is configured to switch an energy supply of the catalytic device to said local energy store in an event of a failure of said central current supply device. claim 3 6. The combination according to 1 , wherein said portion of said predetermined catalytic surface is disposed centrally within said number of catalyst bodies of the catalytic device. 7. The combination according to claim 1 , which further comprises a heat conductor leading from said portion of said predetermined catalytic surface to another portion of said predetermined catalytic surface. claim 1 8. The combination according to claim 7 , wherein said heat conductor is a metallic conductor. claim 7 9. The combination according to claim 1 , wherein said energy feed device comprises a storage device with energy storage material selected from the group consisting of liquid and solid energy storage material, and a heat transport element thermally connecting said storage device to said portion of said predetermined catalytic surface. claim 1 10. The combination according to claim 9 , which further comprises a heater for heating said storage device. claim 9 11. The combination according to claim 10 , wherein said heater is an electrical resistance heater. claim 10 12. The combination according to claim 9 , wherein said storage device is a heat store surrounded by insulation. claim 9 13. The combination according to claim 10 , wherein said heater is an electrical heating device with a permanently heated heating coil. claim 10 14. The combination according to claim 10 , wherein said heater is a heating body disposed between two mutually adjacent catalyst bodies. claim 10 15. The combination according to claim 10 , wherein each of said number of catalyst bodies is a plate, and said heater is a heating conductor track extending parallel to said plate. claim 10 16. The combination according to claim 10 , which further comprises a housing surrounding said heater and the catalyst bodies. claim 10
043141579	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the figures and particularly to FIG. 1, a radiography exposure device 20 is depicted. The device 20 includes a pistol grip cable drive 22, the safety lock 24 of the invention, a shield 26 and a source of radiation 28 which is shown extended from the shield 26. The pistol grip cable drive 22 includes a pistol grip 30 and a crank 32 rotatably mounted thereto. Crank 32 can extend radiation source 28 from shield 26 when it is turned in the indicated clockwise direction and can retract source 28 into shield when the crank is turned into the indicator counterclockwise direction. Cable drive 22 further includes cable guide tubes 34 and 36. Guide tube 34 is connected to lock 24 and guide tube 36 is positioned dependently below guide tube 34. When the radiation sources is being extended from the shield 26, the cable 38 upon which the radiation source 28 is mounted moves from cable guide tube 36 around crank 32 and through cable guide tube 34. When the source 28 is being retracted into shield 26, the cable 38 moves through cable guide tube 34 around crank 32 and is stored in cable guide tube 36. It is to be understood that the radiographer or operator of the radiography exposure device for purposes of safety stands many feet away from the shield 26 when the source 28 is extended therefrom in order to make the above reference inspections. Thus, the cable guide tubes 34 and 36 are many feet long so that the pistol grip 30 is quite removed from the shield 26. Further as the source 28 must in some instances be moved many feet outside of the shield in order to be correctly positioned for making the necessary inspections, the cable guide tube 36 must be sufficiently long to store the excessive cable length as the source of radiation 28 is retracted into the shield 26. Examining the shield 26 and the safety lock 24 of the invention, it can be seen in FIG. 2 that the shield 26 includes a housing 40 and a carrying handle 42. An S-shaped tube 44 is provided in the housing 40 for receiving the source of radiation 28. S-shaped tube 44 is comprised of titanium in a preferred embodiment. It is to be appreciated that the radiation source 28 is held in the middle of the S-shaped tube in the locked or stored position to further isolate the radiation source from the openings at the end of said S-shaped tube which are then not in line with said radiation source. Surrounding the S-shaped tube 44 is radiation shield material 46 which isolates the radiation source 28 from the environment. Radiation shield material 46 is supported and cushioned by foam material 47. As presented in FIG. 2, the shield 26 contains the radiation source 28 in a locked and secure position so that the shield and the source can be transported to the work site. For the purpose of transportation, the cable 38 includes a disconnectable pig tail 48 onto which the radiation source 28 is mounted. A cable connector 50 is located on the opposite end of pig tail 48 from the radiation source 28. As can be seen in FIG. 4, connector 50 includes a housing 51 which contains a spring biased pin 53 which is actuated by peg 55. With pin 53 moved rightwardly in FIG. 4 a mating end of the cable 38 can be inserted in slot 57 defined by housing 51. When peg 55 and thus pin 53 are released, cable 38 is positively locked in connector 50. Spaced from the radiation source 28 is a stop 52 which is selectively trapped by the safety lock 24 of the invention, as will be discussed hereinbelow. For purpose of transportation, a cap 54 is placed over the connector 50 to prevent dust and other contaminants from entering the safety lock 24. Additionally, for purposes of safety and transportation, a safety plug 56 is inserted into the end of the S-shaped tube 44 from which the radiation source 28 extends. Safety cap 56 includes a short pig tail cable 58 with a blunted end 60. End 60 is positionable immediately adjacent the radiation source 28, in the middle portion of the S-shaped tube 44, for purposes of isolating and positively positioning the radiation source 28 during transportation of the shield 26. FIG. 3 depicts an end elevational view of the shield 26 with the cap 54 placed over the end of the connector 50. Turning to FIG. 4, an exploded perspective view of the safety lock 24 of the invention is depicted. Safety lock 24 includes a lock housing 62 which is welded along line 64 to the housing 40 of the shield 26 with a heli-arc welding technique so the lock housing cannot be easily removable from the shield 26. Safety lock 24 further includes a locking means on cylindrical key lock 66 having key 68, which locking means 66 is received in a first bore 70 defined by the lock housing 62. Bore 70 is counter sunked to receive the flange portions of the key 68. Key 68 is of the type having a cylindrical barrel 72 which is received in annular channel 74. Cylinder barrel 72 includes teeth (not shown) on the internal surface thereof, which teeth mate with the cylinder key lock housing 69 to allow an internal portion 76 of the cylinder key lock 66 and pin 77, eccentrically mounted to internal portion 76, to turn as key 68 is turned. Upstanding from cylinder barrel 72 is a tab 78 which is slidable into a key way 80. When the key 68 is inserted in the cylinder key lock housing 69 and turned to effect turning of the eccentric pin 77, tab 78 lockingly secures key 68 in housing 69. The non-rotating outer portion of housing 69 is positionably secured with respect to the housing 62 of the safety lock 24 by a set screw 82 received in threaded bore 84. Located immediately below cylindrical key lock 66 is the means 86 for receiving the stop 52 of the pig tail cable 58. Said receiving means 86 includes a retaining cylinder 88 defining a central threaded bore 90 for receiving a mating end of cable guide tube 34. Further, receiving means 86 includes a spring 92 and a annular receiver 94 having a central bore 96. Receiving means 86 is received in a second bore 98 defined by lock housing 62. Further, housing 62 defines additional bores 100, 102 and 107 which communicate with bore 98. Bore 96 of receiver 94 is aligned with bore 100 and engaging means or pins 104 and 105, extending from receiver 94, are received through bores 102 and 107. As will become apparent hereinbelow, pin 104 extends farther from receiver 94 than does pin 105. The spring 92 is held between retaining cylinder 88 and receiver 94 in bore 98 and said retaining cylinder 88 is held in position relative to bore 98 by a plurality of said set screws 106. Safety lock 24 includes a trapping means 108 which includes a slide 110 received in a rectangular passage 112 defined by lock housing 62. As can be seen in FIG. 4, bores 70 and 98 are substantially parallel to each other and perpendicular to slide 110 and passage 112. The upper end of slide 110 includes an indicator tab 111. Slide 110 includes a first aperture 114 which has a first substantially vertical and elongate aperture portion 116 and a second sloping and elongate aperture portion 118 directed downwardly from the upper most portion of the vertical portion 116. Slide 110 further includes an additional elongate bore 120 which is positioned to selectively receive the end of pin 104 which extends from annular receiver 94. Located adjacent the bottom portion of slide 110 is an indentation 122 which can selectively receive the end of pin 105. Adjacent indentation 122 and communicating with the lower edge of slide 110 is an additional aperture 124. Additional aperture 124 includes an upper portion 126 which is sized to receive pig tail cable 48 but not stop 52 and a middle portion 128 which is sized to receive stop 52 which communicates with upper portion 126. Further, aperture 124 includes a lower portion 130 which communicates with middle portion 128 and with the lower edge of slide 110. Lower portion 130 is sized to receive the pig tail cable 48 but not the stop 52. Slide 110 is biased upwardly in rectangular passage 112 by a spring arrangement 134. Spring arrangement 134 includes a spring 136 and a guiding and supporting elongate pin 138. Spring 136 and pin 138 are received in passage 112 with the head of pin 138 being received in an indentation 140 which communicates with said passage 112. Further, an end of spring 134 contacts a shoulder 141 of slide 110. OPERATION OF THE INVENTION The fully locked position for the safety lock 24 is shown in FIGS. 9 and 10. As can be seen in FIG. 9, in the fully locked position, the key 68 can be removed from the key housing 69, so that said key can be stored separately from the exposure device 20 so that no unauthorized use can be made of the device. Further as the key is a cylinder type strong box key the likelihood of the cylinder lock 66 being opened by available substitutes for the key are remote. With the source 28 in the locked position, eccentric pin 77 is positioned in the lower end of the sloping portion 118 of aperture 114 to lock slide 110 in its lower most position. Simultaneously stop 52 is received in bore 100 and against receiver 94 and is retained therein as the upper portion 126 of aperture 124 is aligned with the bore 100 restricting the movement of stop 52. Pin 104 is urged through elongate bore 120 by the spring 92. To unlock the safety lock, the key 68 is inserted into the cylinder housing 69 and given a quarter turn to the right so that pin 77 is positioned at the upper end of the vertical portion 116 of aperture 114. Crank 32 is then cranked so that cable 38 is retracted, causing the stop 52 to urge annular receiver 94 rearwardly compressing spring 92 against receiving cylinder 88. As this occurs pin 104 is removed from elongated bore 120 and spring 136 urges slide 110 upwardly until slide 110 is stopped by eccentric pin 77 contacting the lower end of vertical portion 116 of aperture 114. With the slide 110 in this position (FIGS. 5, 6), tab 111 extends furthest from housing 62 and gives a visual indication to the operator that he is operating safety lock 24. Stop 52 is still trappingly retained in bore 100 by the lowermost portion 130 of additional aperture 124. At this point pin 104 is first received in aperture 124 between upper portion 126 and middle portion 128. In order to untrap the stop, the operator must urge the slide 110 downwardly into position as shown in FIGS. 7 and 8 so that pin 105 is received in indentation 122 so as to determine the position of slide 110. With slide 110 in said position, the middle portion 128 of aperture 124 is aligned with bore 100 so that crank 32 can urge stop 52 through said middle portion into the S-shape tube 44 of the shield 26 and simultaneously urge the source 28 out of the shield 26. It is to be understood, that in the positions shown in FIGS. 5, 6, 7, and 8, key 68 cannot be removed from the key housing 69 and thus no authorized copies of said key can be made. After the radiography procedures are performed, the source 28 is retracted back into the shield 26 and the stop 52 is drawn through the middle portion 128 of the aperture 124 until it rests in bore 100. Retraction of stop 52 urges annular receiver 94 against spring 92 and receiving cylinder 88, so as to remove pin 104 from indentation 122 allowing spring 138 to urge slide 110 upwardly until tab 111 is in its upwardly most position as shown in FIGS. 5 and 6. Again, there is visual indication given by tab 111 that the stop 52 and thus the radiation source 28 are in the trapped position. At this point either the slide 110 can be reset into the positions of FIGS. 7 and 8, to allow the source 28 to be again extended from the shield 26 to do additional radiography, or lock 24 can be operated to place the slide in the positions of FIGS. 9 and 10 preparatory to removing key 68. It is to be understood that with the lock in the position as shown in FIGS. 7 and 8, the stop 52 can always be received in the bore 100 so as to trap the stop 52 and thus the radiation source 28 in the shield 26 each time the source 28 is retracted into the shield 26. Thus, the safety lock does not prevent the return of this source to the shielded position. Assuming that the radiography procedures are completed, and that the source is to be locked in the trapped position, tab 111 of slide 110 is urged downwardly after the cable has been retracted so as to remove pins 104 and 105 from the path of slide 110. Thus, slide 110 can be urged downwardly against spring 136 until eccentrically mounted pin 77 contacts the upper most portion of vertical aperture portion 116. In this position, upon the release of cable 38, the pin 104 is urged by spring 92 into elongated bore 120 as can be seen in FIGS. 9 and 10. The shorter pin 105 contacts the side of slide 110 at a point spaced from indentation 122. With the slide in this position the key can be turned in a counterclockwise manner to lock the slide in position. With the eccentrically mounted pin 77 in the position shown in FIG. 10, the key 68 can be removed from the lock. It is to be understood that bore 96 of annular receiver 94 has a diameter which is smaller than stop 52. Thus the source 28 can not be removed through the back of the safety lock through bore 96 even when the safety lock is in the unlocked and untrapped position. As it can be seen that the above safety lock meets all the guidelines set forth by the Nuclear Regulatory Commission and is simpler and more efficient than the existing prior art. In particular, the present lock includes a housing 62 which is not easily removable from the shield with readily available tools as the housing is heli-arc welded to the shield, and thus, when the safety lock 24 is locked, it is difficult to remove the source of radiation from the shield except with the correct key. Also, the safety lock 24 does not prevent the return of the source into the shielded position as the safety lock only traps the stop 52 when it is in the position as indicated in FIGS. 5 and 6 so that the source of radiation is in the middle portion of the S-shaped tube 44. Additionally, it is not possible to unlock the safety lock 24 with an easily available substitute for the key as the key 68 is a cylinder type strong box key. Further, it is to be understood that it is not possible to operate the cylindrical key lock 66, due to the arrangement of slide 110, to remove said key 68 from key housing 69 until the stop 52 is trapped by slide 110 and thus until the source is in the fully shielded position in shield 26. Finally the tab 111 provides an indication of the position of source 28 and also the state of safety lock 24, thus reducing the chance of inadvertent exposure of the radiographer to the source of radiation. Other aspects, objects and advantages of the invention can be obtained from the study of the drawings, the disclosure and the appended claims.
	summary
054266807	summary	FIELD OF THE INVENTION This invention relates generally to maintenance of a control rod drive of a boiling water reactor. Specifically, the invention relates to tools for removal of a control rod drive during the exchange process. BACKGROUND OF THE INVENTION Control rod drives (CRDs) are used to position control rods in boiling water reactors (BWRs) to control the fission rate and fission density, and to provide adequate excess negative reactivity to shutdown the reactor from any normal operating or accident condition at the most reactive time in core life. Referring to FIG. 1, each CRD is mounted vertically in a CRD housing 10 which is welded to a stub tube 8, which in turn is welded to the bottom head of the reactor pressure vessel 4. The CRD flange 6 is bolted and sealed to the flange 10a of the CRD housing 10, which contains ports for attaching the CRD hydraulic system lines 80, 81. Demineralized water supplied by the CRD hydraulic system serves as the hydraulic fluid for CRD operation. As shown schematically in FIG. 1, the CRD is a double-acting, mechanically latched hydraulic cylinder. The CRD is capable of inserting or withdrawing a control rod (not shown) at a slow controlled rate for normal reactor operation and of providing rapid control rod insertion (scram) in the event of an emergency requiring rapid shutdown of the reactor. A locking mechanism in the CRD permits the control rod to be positioned at 6-inch (152.4-mm) increments of stroke and to be held in these latched positions until the CRD is actuated for movement to a new position. A spud 46 at the top of the index tube 26 (the moving element) engages and locks into a socket at the bottom of the control rod. Once coupled, the CRD and control rod form an integral unit which must be manually uncoupled by specific procedures before a CRD or control rod may be removed from the reactor. When installed in the reactor, the CRD is wholly contained in housing 10. The CRD flange 6 contains an insert port 66, a withdraw port 70 and an integral two-way check valve (with a ball 20). For normal drive operation, drive water is supplied via an associated hydraulic control unit (HCU) to the insert port 66 for drive insertion and/or to withdraw port 70 for drive withdrawal. For rapid shutdown, reactor pressure is admitted to the two-way check valve from the annular space between the CRD and a thermal sleeve (not shown) through passages in the CRD flange, called scram vessel ports. The check valve directs reactor pressure or external hydraulic pressure to the underside of drive piston 24. Referring to FIGS. 2A and 2B, the CRD further comprises an inner cylinder 57 and an outer tube 56, which form an annulus through which water is applied to a collet piston 29b to unlock index tube 26. The internal diameter of inner cylinder 57 is honed to provide the surface required for expanding seals 65 on the drive piston 24. A collet housing 51 (which is part of outer tube 56) is provided with ports 73 to permit free passage of water from the clearance space between the outer diameter of index tube 26 and the inner diameter of inner cylinder 57 and the inner diameter of collet housing 51. The bottom of collet piston 29b normally rests against a spacer 52 in the upper portion of the annular space. Grooves in the spacer permit the passage of water between the bottom of the collet piston 29b and the passage area within the cylinder, tube and flange. Welded pipes 80 and 81, installed in the CRD housing, port water to the insert port 66 and the withdraw port 70 respectively. A port 69 below outer tube 56 connects to withdraw port 70 in CRD flange 6 so that water is applied through the annulus to collet piston 29b when a withdraw signal is given. The CRD is secured to the CRD housing flange 10a by eight mounting bolts (not shown). A pressure-tight seal is effected between the mated flanges by O-ring gaskets (not shown) mounted in a spacer 7 secured to the CRD flange face. Insert port 66 contains a ball check valve which consists of check-valve ball 20, ball retainer 21, and retainer O-ring 22. This valve directs HCU accumulator pressure or reactor pressure to the underside of drive piston 24 during scram operation. Port 66 is connected internally to the annulus and the bottom of drive piston 24 and serves as the inlet for water during normal insertion or scram. Water enters this port for a brief period in response to a withdraw signal to move the index tube 26 upward so that collet fingers 29a are cammed out. Following this brief unlocking period, water from below drive piston 24 is discharged through port 66 and through the under-piston hydraulic line for the duration of the withdraw signal. During the time the CRD remains stationary, cooling water passes through an annulus internal to flange 6 to the area between outer tube 56 and the inside of the thermal sleeve to cool the CRD. The withdraw port 70 serves as the inlet port for water during control rod withdrawal and as the outlet port for water during normal or scram insertion. It connects with internal porting and annuli to the area above drive piston 24. During a withdraw operation, water is supplied from port 70 through a small connecting port in CRD flange 6 to the annular space between outer tube 56 and inner cylinder 57 for application to the bottom of collet piston 29b. The locking mechanism consists of collet fingers 29a, collet piston 29b, barrel 35, guide cap 39, and collet spring 31. The mechanism is contained in the collet housing 51 portion of outer tube 56 and is the means by which index tube 26 is locked to hold the control rod at a selected position. The collet assembly consists of a collet piston 29b fitted with four expansion piston seal rings 28, six fingers 29a and a retainer (not shown) and is set into a bore in the collet housing 51. In addition, a spring 31, barrel 35 and guide cap 39 complete the components installed in the collet housing 51. Guide cap 39 is held in place above the collet by three plugs 37 which penetrate the upper end of collet housing 51, and which are held in place by fillister-head screws. It provides a fixed camming surface to guide collet fingers 29a upward and away from index tube 26 when unlocking pressure is applied to collet piston 29b. Barrel 35 is installed below guide cap 39 and serves as fixed seat for collet spring 31. The collet mechanism requires a hydraulic pressure greater than reactor pressure to unlock for CRD-withdraw movement. A preload is placed on collet spring 31 at assembly and must be overcome before the collet can be moved toward the unlocked position. For control rod withdrawal, a brief insert signal is applied to move index tube 26 upward to relieve the axial load on collet fingers 29a, camming them outward against the sloping lower surface of index tube locking notch 55. Immediately thereafter, withdraw pressure is applied. In addition to moving index tube 26 downward, this pressure is at the same time applied to the bottom of collet piston 29b to overcome the spring pressure and cam the fingers 29a outward against guide cap 39. When the withdraw signal ceases, the spring pressure forces the collet downward so that fingers 29a slip off guide cap 39. As index tube 26 settles downward, collet fingers 29a snap into the next higher notch and lock. When Collet fingers 29a engage a locking notch 55, collet piston 29b transfers the control rod weight from index tube 26 to the outer tube 56. Unlocking is not required for CRD insertion. The collet fingers are cammed out of the locking notch as index tube 26 moves upward. The fingers 29a grip the outside wall of index tube 26 and snap into the next lower locking notch for single-notch insertion to hold index tube 26 in position. For scram insertion, index tube 26 moves continuously to its limit of travel during which the fingers snap into and cam out of each locking notch as index tube 26 moves upward. When the insert, withdraw or scram pressures are removed, index tube 26 settles back, from the limit of travel, and locks to hold the control rod in the required position. The drive piston 24 and index tube 26 are the primary subassembly in the CRD, providing the driving link with the control rod as well as the notches for the locking mechanism collet fingers. Drive piston 24 operates between positive end stops, with a hydraulic cushion provided at the upper end only. Index tube 26 is a nitrided stainless-steel tube threaded internally at both ends. The spud 46 is threaded to its upper end, while the head of the drive piston 24 is threaded to its lower end. Both connections are secured in place by means of lock bands 25, 44. There are 25 notches machined into the wall of index tube 26, all but one of which are locking notches 55 spaced at 6-inch intervals. The uppermost surfaces of these notches engage collet fingers 29b, providing 24 increments at which a control rod may be positioned and preventing inadvertent withdrawal of the rod from the core. The lower surfaces of the locking notches slope gradually so that the collet fingers cam outward for control rod insertion. Drive piston 24 is provided with internal (62, 71, 72) and external seal rings (65), and is operated in the annular space between piston tube 15 and inner cylinder 57. Internal (63) and external (64) bushings prevent metal-to-metal contact between drive piston 24 and the surface of piston tube 15 and the wall of inner cylinder 57 respectively. When a control rod is driven upward to its fully inserted position during normal operation or scram, the upper end of the piston head contacts the spring washers 30 which are installed below the stop piston 33. Washers 30 and stop piston 33 provide the upper limit of travel for drive piston 24. The spring washers, together with the series of buffer orifices 53 in the upper portion of piston tube 15, effectively cushion the moving drive piston 24 and reduce the shock of impact when the piston head contacts the stop piston. The magnet housing, which comprises the lower end of drive piston 24, contains a ring magnet 67 which actuates the switches inside a position indicator probe 12a to provide remote electrical signals indicating control rod position. The piston tube assembly forms the innermost cylindrical wall of the CRD. It is a welded unit consisting of piston tube 15 and a position indicator tube 61. The piston tube assembly provides three basic functions for CRD operation: (a) position indicator tube 61 is a pressure-containing part which forms a drywell housing for position indicator probe 12a (see FIG. 2A); (b) piston tube 15 provides for the porting of water to or from the upper end of the piston head portion of drive piston 24 during rod movement; and (c) during control rod scram insertion, buffer orifices 53 in piston tube 15 progressively shut off water flow to provide gradual deceleration of drive piston 24 and index tube 26. A stud 59 is welded to the upper end of tube piston 5. Stud 59 is threaded for mounting the stop piston 33. A shoulder on the stud, just below the threaded section, is machined to provide a recess for the spring washers 30 that cushion the upward movement of drive piston 24. The tube section 15a and head section 15b of piston tube 15 provide space for position indicator tube 61, which is welded to the inner diameter of the threaded end of head section 15b and extends upward through the length of tube section 15a, terminating in a watertight cap near the upper end of the tube section. Piston tube 15 is secured by a nut 16 at the lower end of the CRD. Two horizontal ports are provided in the head section 15b, 180.degree. apart, to transmit water between the withdraw porting in the CRD flange and the annulus between indicator tube 61 and tube section 15a of piston tube 15 for application to the top of drive piston 24. Three O-ring seals 18 are installed around head section 15b. Two seal the bottom of the CRD against water leakage and one seals the drive piston 24 under-piston pressure from the drive piston over-piston pressure. A position indicator probe 12a is slidably inserted into indicator tube 61. As shown in FIGS. 2A and 4, probe 12a is welded to a plate 12b, which plate is in turn bolted to housing 12. Housing 12 is secured to the CRD ring flange 17 by screws 13. A cable clamp 11, located at the bottom of a plug 106, secures a connecting electrical cable (not shown) to plug 106. Ring flange 17 is in turn secured to the CRD housing by screws 9. Thus, probe 12a, housing 12 and cable clamp 11 (with the cables passing therethrough) can be removed as a unit. Probe 12a includes a switch support 103 with 53 reed switches and a thermocouple for transmitting electrical signals to provide remote indications of control rod position and CRD operating temperature. Only switches S48, S49 and S50 are shown in FIG. 4. The reed switches are connected by electrical wires 105 to a receptacle 14, which receives plug 106. The plug and receptacle are standard electrical components with 27 pins and sockets respectively. Housing 12 serves as a protective covering for the electrical wires 104. The switch support assembly consists of a switch support 103 and a flange (not shown). The switch support 103 has two channels extending its full length which provide for mounting of the position switches on two sides of the support. A thin-walled protective tube 107 is installed over the length of the switch support. Tube 107 is held in place by a split rivet (not shown) which penetrates the switch support at the upper end. The 53 reed switches are identical and are attached to switch support 103 by spring clips 109. Each switch is encased in a silicone-impregnated fiberglass sleeve for insulation. The switches are normally open and are closed individually during CRD operation by ring magnet 67 installed in the bottom of drive piston 24. The stop piston 33 threads onto the stud 59 at the upper end of piston tube 15. This piston provides the seal between reactor pressure and the area above the drive piston. It also functions as a positive-end stop at the upper limit of drive piston travel. Six spring washers 30 below the stop piston help absorb the final mechanical shock at the end of travel. Seals 34 include an upper pair used to maintain pressure above the drive piston during CRD withdrawal and a lower pair used only during the cushioning of the drive piston at the upper end of the stroke. Two external bushings 32 prevent metal-to-metal contact between stop piston 33 and index tube 26. As seen in FIG. 3, spud 46, which connects the control rod 90 and the CRD, is threaded onto the upper end of index tube 26 and held in place by locking band 44. The coupling arrangement will accommodate a small amount of angular misalignment between the CRD and the control rod. Six spring fingers permit the spud to enter the mating socket 92 on the control rod. A lock plug 94 then enters spud 46 from socket 92 and prevents uncoupling. Two uncoupling mechanisms are provided. The lock plug 94 may be raised against the return force of a spring 95 by an actuating shaft 96 which extends through the center of the control rod velocity limiter to an unlocking handle (not shown). The control rod, with lock plug 94 raised, may then be lifted from the CRD. The lock plug may also be raised from below to uncouple the CRD from below the reactor vessel. To accomplish this, a special tool is attached to the bottom of the CRD and used to raise the piston tube 15 (see FIG. 2B). This raises an uncoupling rod, lifting lock plug 94 so that spud 46 disengages from the control rod coupling socket 92. The uncoupling rod consists of a rod 48 and a tube 43, supported in the base of the spud at the upper end of the CRD. The rod 48 is welded to the flared end of tube 43 such that a dimension of 1.125 inch exists between the top of rod 48 and the top end of spud 46. This is a critical dimension and must be maintained to ensure proper CRD-and control-rod coupling. For this reason, uncoupling rods cannot be interchanged unless the critical dimension is verified. In addition to its function in uncoupling, rod 48 positions the control rod lock plug 92 such that it supports (i.e., opposes radially inward deflection of) the spud fingers when the control rod and CRD are coupled. In order to perform maintenance on a CRD, the CRD must be removed from the CRD housing. To accomplish this, the CRD must first be uncoupled from the control rod. Conventional practice is to remove the position indicator probe from the CRD prior to drive removal. The purpose is to allow access by an uncoupling tool in the space occupied by the probe. The uncoupling tool is used for final determination that the CRD is uncoupled from the control rod prior to lowering the drive out of its housing. The uncoupling tool is also used to uncouple the drive from the control rod from beneath the RPV, but often this function is performed from the refueling floor. All work performed under vessel is in a high-radiation area and reduction of any time or tasks in the under vessel area results in a reduction in the overall radiation exposure accrued by the utility during an outage. The removal of the position indicator probe under vessel contributes approximately one man-rem to the total radiation exposure received by the crew performing the CRD exchange. SUMMARY OF THE INVENTION The present invention is a method for removing a CRD with the position indicator probe in place. This allows probe removal to be performed in a low-dose area, thereby effectively reducing the exposure received by the crew removing the probe to nearly zero. A further feature of the invention is an electronic tool for continuous CRD uncoupled monitoring during drive removal. The tool uses the position indicator probe to verify that the drive is uncoupled. The electronic monitoring tool is mounted on the CRD removal equipment. The monitoring circuit is connected to selected position switches inside the position indicator probe, which is installed in the stationary CRD piston tube. These selected switches are normally open and are closed When a ring magnet on the movable drive piston is in proximity to the respective switch. Accordingly, the position of the index tube/drive piston assembly, and the control rod coupled thereto via the spud, can be determined from the state of the position switches. The detected state of the switches can be used to determine whether the index tube/drive piston assembly is being extended relative to the piston tube, as the CRD is lowered during the initial stage of removal. Indicator lights are activated in dependence on the position of the ring magnet on the drive piston relative to selected position switches. These lights annunciate a coupled condition wherein the index tube is displacing relative to the piston tube, due to coupling with the control rod, as the unbolted CRD flange is lowered. In response to this annunciation, removal will be discontinued until the drive has been uncoupled.
	description	This application claims the benefit of Japanese Application No. 2003-328260 filed Sep. 19, 2003. The present invention relates to a radiation computed tomographic imaging apparatus such as an X-ray CT (computed tomography) apparatus. More particularly, the present invention relates to a radiation computed tomography apparatus capable of acquiring volume data, such as a VCT (volume CT) apparatus or a multi-row CT apparatus, and a radiation detector for use in such an apparatus. Known X-ray CT apparatuses include, for example, one that acquires projection data for a subject by an X-ray detector having a plurality of X-ray detector channels arranged in a two-dimensional manner. The plurality of X-ray detector channels are positioned to have their width in a direction along a predefined axis with respect to the subject. Since X-ray detector channel rows are formed over a certain width in the axis direction, the X-ray detector having X-ray detector channels arranged in a two-dimensional manner is generally referred to as a multi-row detector. In the multi-row detector, a direction along the axis is sometimes referred to as a column direction, and a direction orthogonal to the column direction as a channel direction, for example. In the X-ray CT apparatus comprising the multi-row detector, projection data of a cross section of the subject is collected by emitting an X-ray fan beam, which has an extent in both the column and channel directions, from a predefined focal spot at a plurality of positions around the axis to the multi-row detector. A tomographic image of the subject is produced by a reconstruction calculation based on the projection data. Patent Document 1 discloses an X-ray CT apparatus having an X-ray detector provided with collimators for the X-ray detector channels, which collimators are arranged in the channel direction and directed toward a focal spot of an X-ray fan beam. In the X-ray detector described in Patent Document 1, each X-ray detector channel is disposed in the channel direction to have its detecting surface for detecting X-rays directed toward the focal spot. [Patent Document 1] Japanese Patent Application Laid Open No. H6-22949. In the imaging using an X-ray CT apparatus, there is a possibility that the detecting surfaces in the X-ray detector may be struck also by X-rays other than those directly impinging upon the detecting surfaces from a focal spot, i.e., for example, by scatter X-rays (scatter rays), which are caused by X-rays having their direction of travel deflected due to collision with an object, such as bone, in the subject. The scatter rays contain projection information on the subject that the X-ray detector channels receiving the scatter rays should not detect. Therefore, the scatter rays cause generation of artifacts, and image quality of the tomographic image may be degraded. Since the X-ray CT apparatus disclosed in Patent Document 1 has the collimators in the channel direction, scatter rays can be prevented from impinging upon the detecting surfaces to some extent. However, when the detector channels are arranged in more than one row and a fan beam is used to acquire projection data, the X-ray fan beam must have a larger width. The increase in the width of the X-ray fan beam causes X-rays to impinge upon more divergent positions in the subject, thus increasing the probability of generation of scatter rays. It is therefore difficult for a collimator merely provided at each X-ray detector channel in the channel direction, as in the X-ray CT apparatus described in Patent Document 1, to effectively prevent scatter rays from impinging upon the detecting surface. Consequently, image quality is more likely degraded. It is therefore an object of the present invention to provide a radiation computed tomographic imaging apparatus capable of more effectively reducing the influence by scatter rays, and improving image quality of a tomographic image. It is another object of the present invention to provide a radiation detector for use in a radiation computed tomographic imaging apparatus, capable of more effectively reducing the influence by scatter rays, and improving image quality of a tomographic image. A radiation computed tomographic imaging apparatus, in accordance with the present invention, comprises: a radiation source for emitting radiation while rotating around a predefined axis of rotation; a radiation detector for detecting said radiation passing through a subject around said axis of rotation, said radiation detector having a plurality of radiation detector elements for detecting said radiation, extending in a two-dimensional manner in first and second arrangement directions, said first arrangement direction being contained in a plane of rotation of said radiation source, said second arrangement direction being orthogonal to said first arrangement direction and aligned along said axis of rotation; and reconstructing means for arithmetically reconstructing tomographic image data for a tomographic image of said subject based on projection data of said subject obtained from said radiation detected by said radiation detector, wherein said radiation detector comprises collimators for confining an angle at which said radiation impinges upon said radiation detector elements, said collimators being provided at borders between said radiation detector elements adjoining in said second arrangement direction. A radiation detector in accordance with the present invention is a radiation detector for use in a radiation computed tomographic imaging apparatus for generating tomographic image data for a tomographic image of a subject based on projection data of said subject obtained from radiation emitted from a radiation source rotating around a predefined axis of rotation and passing through said subject, which comprises: a plurality of radiation detector elements for detecting said radiation for acquiring said projection data, extending in a two-dimensional manner in first and second arrangement directions, said first arrangement direction being contained in a plane of rotation of said radiation source, said second arrangement direction being orthogonal to said first arrangement direction and aligned along said axis of rotation; and collimators for confining an angle at which said radiation impinges upon said radiation detector elements, provided at borders between said radiation detector elements adjoining in said second arrangement direction. In the present invention, a radiation detector is comprised of radiation detector elements extending in a two-dimensional manner in first and second arrangement directions. The first arrangement direction is contained in a plane of rotation of a radiation source around a predefined axis of rotation, and the second arrangement direction is orthogonal to the first arrangement direction and aligned along the axis of rotation. At the borders between the radiation detector elements adjoining in the second arrangement direction of the radiation detector, collimators are provided. The radiation emitted from the radiation source impinges upon the radiation detector elements with its angle confined by the collimators in the second arrangement direction. Under such a condition, the radiation passing through the subject is detected by the radiation detector around the predefined axis. According to the present invention, the influence by scatter rays is more effectively reduced, and image quality of a tomographic image can be improved. The present invention can be applied to a computed tomographic imaging (CT) apparatus employing radiation. Moreover, the present invention can be applied to a radiation detector for use in a CT apparatus. Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings. Embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that radiation in the present invention includes X-rays. The following description will be made exemplifying an X-ray CT apparatus employing X-rays as the radiation. FIG. 1 is a diagram showing the general configuration of an X-ray CT apparatus in accordance with an embodiment of the present invention. The X-ray CT apparatus 10 shown in FIG. 1 comprises an X-ray CT apparatus main body 10A and a console 10B. One embodiment of the radiation computed tomography apparatus of the present invention is the X-ray CT apparatus 10 shown in FIG. 1. The X-ray CT apparatus main body 10A comprises a rotating section 2 and a data acquisition system (DAS) 20, as shown in FIG. 1. One embodiment of the moving means in the present invention corresponds to the rotating section 2. The rotating section 2 comprises an X-ray source XL for emitting X-rays, and an X-ray detector 70 for detecting the X-rays emitted by the X-ray source XL. The X-ray source XL emits a fan-shaped X-ray beam 5 from an X-ray focal spot 3. The fan-shaped X-ray beam 5 is sometimes referred to as a fan beam. The intensity of the X-ray beam 5 is detected by an X-ray detector 70. The X-ray detector 70 has a plurality of detector channels ch arranged in a two-dimensional matrix (array), as shown in FIG. 2. An embodiment of the radiation detector elements in the present invention corresponds to the detector channels ch. Each detector channel ch is made by, for example, a combination of a scintillator and a photodiode. The detector channels ch arranged in a two-dimensional manner are designated by a column index i along the row direction and a row index j along the column direction. The number of column indices i is of the order of 1000, and the number of row indices j is of the order of 16, for example. The row direction is sometimes referred to as the channel direction here. The detector channels ch lined up in a row in the channel direction are together referred to as a detector channel row. In the column direction, a plurality of detector channel rows 7 are juxtaposed to one another in parallel. An embodiment of the first arrangement direction in the present invention corresponds to the row direction (channel direction), and an embodiment of the second arrangement direction corresponds to the column direction. As shown in FIGS. 1 and 2, the column direction in the X-ray detector 70 is defined as the z-axis direction. A plane orthogonal to the z-axis is defined as an x-y plane. The X-ray beam 5 is a fan beam having an extent in both the x-y and x-z planes. A detecting surface Su of each detector channel ch can individually and independently detect X-ray intensity of the X-ray beam 5, and data corresponding to the number of the detector channels ch arranged in a two-dimensional manner can be obtained. Detailed description on the X-ray detector 70 will be made later. A subject 1 is positioned between the X-ray source XL and X-ray detector 70. The X-ray source XL and X-ray detector 70 of the X-ray CT apparatus 10 in accordance with the present embodiment are rotated around a predefined axis O by the rotating section 2 as shown in FIG. 1 while maintaining their positional relationship relative to each other. An embodiment of the axis of rotation in the present invention corresponds to the axis O. For example, the body axis direction of the subject 1 from head to toe is made to coincide with the direction of the axis O. Moreover, the direction of the axis O coincides with the z-axis direction in FIG. 1. Collection of X-ray intensity data is achieved by a scan in which the intensity of the X-ray beam 5 passing through the subject 1 is detected by the detector channels ch in a sequentially varying direction of emission of the X-ray beam 5 toward the subject 1 while rotating the X-ray source XL and X-ray detector 70 around the axis O by the rotating section 2. Data in a plurality of directions in one rotation around the axis O are thus obtained. The direction of data collection is referred to as a view. In FIG. 1, a reference symbol k represents a view index. The number of views per rotation is of the order of 1000, for example. In this case, the spacing Δθ between the views shown in FIG. 1 is of the order of 360°/1000. The DAS 20 collects a plurality of sets of the data acquired by the X-ray detector 70. The DAS 20 converts analog data of X-ray intensity detected by the X-ray detector 70 into digital data, and sends them to the console 10B. The digital data sent to the console 10B represent projection data of a cross-sectional plane through which the X-ray beam 5 passes in the subject 1. As shown in FIG. 1, the console 10B comprises a calculation/control apparatus 23 and a display device 25. One embodiment of the reconstructing means in the present invention corresponds to the calculation/control apparatus 23. The calculation/control apparatus 23 is implemented by hardware, such as a CPU (central processing unit), and software for driving the hardware, for example. The calculation/control apparatus 23 receives the projection data collected by the DAS 20. The calculation/control apparatus 23 performs a reconstruction calculation, such as backprojection, based on the received projection data to generate image data. The image data generated based on the projection data represents an image of a cross section through which the X-ray beam 5 passes in the subject 1, i.e., image data for a tomographic image (tomographic image data). Moreover, the calculation/control apparatus 23 controls the X-ray CT apparatus 10 for tomographic image production to execute operations including rotation of the X-ray source XL and X-ray detector 70 by the rotating section 2 and acquisition of projection data via the DAS 20. Furthermore, the calculation/control apparatus 23 conducts control for displaying the produced tomographic image on the display device 25, such as a CRT (cathode-ray tube) or a liquid crystal display panel. The display device 25 also displays an operation image for operating the X-ray CT apparatus 10. The calculation/control apparatus 23 is connected with an input device, such as a keyboard (not shown). Instructions from a human operator operating the X-ray CT apparatus 10 are input to the calculation/control apparatus 23 via the input device. The X-ray detector 70 in the present embodiment will now be described in detail. As shown in FIG. 2, the X-ray detector 70 having the plurality of detector channels ch arranged in a two-dimensional manner forms a curve along the direction of rotation of the X-ray source XL and X-ray detector 70 around the axis O. In this case, the X-ray detecting surface Su of each detector channel ch is directed toward the X-ray focal spot 3 in the channel direction. The channel direction may be regarded as a direction contained in a plane of rotation of the X-ray source XL and X-ray detector 70 around the axis O. On the other hand, in the column direction orthogonal to the channel direction and along the z-axis direction, the detector channels ch are straightly arranged in a direction parallel to the z-axis. Thus, the detecting surfaces Su are not all directed toward the X-ray focal spot 3, but uniformly face in different directions, one of which is the X-ray focal spot 3 direction. The length L of the X-ray detector 70 in the channel direction shown in FIG. 2 is of the order of 1000 mm, for example. The length W in the column direction is of the order of 30–50 mm, for example. However, the length W may increase with an increase in the number of detector channel rows 7. In the present embodiment, the X-ray detector 70 is provided with collimators 50 extending in the channel direction, at the borders between the detector channels ch adjoining in the column direction. Each collimator 50 is formed in a rectangular plate, for example. Each collimator 50 is directed in a direction normal to the detecting surfaces Su, for example. It should be noted that although an apparatus (not shown) provided near the X-ray focal spot 3 for fan-shaping the X-ray beam 5 is also sometimes referred to in the art as a collimator, the collimators 50 in the present embodiment are different from that collimator for shaping the X-ray beam 5. FIG. 3 is a diagram showing the positional relationship between the X-ray focal spot 3 and X-ray detector 70 as viewed in the x-axis direction in FIG. 1. It should be noted that FIG. 3 is illustrative, and the scale is not an actual one. By providing the aforementioned collimators 50, the incident angle of X-rays on the detecting surfaces Su is confined in the column direction. Therefore, scatter X-rays (scatter rays) are less likely to impinge upon the detecting surfaces Su and be detected, and the influence by scatter rays is reduced. The scatter rays are caused by X-rays having their direction of travel deflected due to collision with an object in the subject 1 that has extremely different X-ray permeability, such as bone. Therefore, it can be considered that some scatter rays will always be generated in imaging the subject 1. As an increase in the number of rows in the X-ray detector 70 enlarges the width of the X-ray beam 5 in the column direction, the X-ray beam 5 is directed onto a wider area in the subject 1, resulting in generation of more scatter rays and accordingly an increase in the probability that the detector channels ch pick up scatter rays. From the viewpoint of causing only X-rays directly reaching detector channels ch from the X-ray focal spot 3 to impinge upon the detecting surfaces Su, and blocking scatter rays by the collimators 50, the collimators 50 are preferably constructed by using a material of high X-ray absorptivity such as tungsten. However, too many collimators 50 may reduce efficiency of X-ray usage because X-rays that would otherwise directly impinge upon the detecting surfaces Su are blocked by the collimators 50. Thus, in the present embodiment, the collimators 50 are provided at predetermined intervals in the column direction, as exemplarily shown in FIG. 3. For example, the collimators 50 are provided at regular intervals in the column direction. The interval between the collimators 50 is preferably of the order of 10–20 mm, for example, from the viewpoint of trade-off between maintenance of efficiency of X-ray usage and reduction of scatter rays. As shown in FIG. 3, the X-ray detector 70 in accordance with the present embodiment is configured to be symmetric in the column direction along the z-axis with respect to a line SAL connecting a midpoint ct and the X-ray focal spot 3. Then, it is preferred that no collimator 50 be provided at the borders between the detector channels ch at and near the center ct, and the collimators 50 be provided at the borders between the detector channels ch other than those at and near the center ct. This is done for preventing the higher efficiency in X-ray usage in the detector channels ch at and near the center ct from decreasing, because the distance from the X-ray focal spot 3 to the detecting surfaces Su of the detector channels ch there is shorter than the distance to the detector channels ch lying in the outer side in the column direction, resulting the higher efficiency in X-ray usage. By providing the collimators 50 as described above, however, when exposed to the X-ray beam 5, a shadowed portion is created by a collimator 50 in a detector channel ch that lies adjacent to that collimator 50 and on the outer side with respect to the collimator 50, as shown in FIG. 3. For example, a detector channel chn+1 in FIG. 3 is shadowed by the collimator 50. On the other hand, a detector channel chn that lies adjacent to the collimator 50 and detector channel chn+1, and lies on the inner side with respect to the collimator 50, is not shadowed by the collimator 50. X-rays cannot directly enter any such shadowed portion created by the collimator 50 from the X-ray focal spot 3, and efficiency of X-ray usage is reduced in the detector channel chn+1, for example. Accordingly, to maintain a certain level of efficiency of X-ray usage in the detector channels ch shadowed by the collimators 50, the height of each collimator 50 is determined so that efficiency of X-ray usage exceeds a certain threshold. The size of the shadowed portion by the collimators 50 varies depending upon the amount of drift of the X-ray focal spot 3. Therefore, the height of each collimator 50 is determined taking drift of the X-ray focal spot 3 into account. The drift of the X-ray focal spot 3 here refers to a position offset of the X-ray focal spot 3 due to, for example, thermal expansion. The process of determining the height of each collimator 50 will now be described in detail. Referring further to FIG. 3, the length of a perpendicular from the X-ray focal spot 3 to the X-ray detector 70 is represented as FD. The width of one detector channel ch in the z-axis direction is represented as CL. Moreover, the amount of drift of the X-ray focal spot 3 with respect to a reference position on a normal to the midpoint ct is represented as D. It should be noted that the amount of drift D may take both positive and negative values depending on the direction of drift of the X-ray focal spot 3. At the reference position, an X-ray beam 5I impinges upon a detector channel chn+1, and an X-ray beam 5D at a drifted position impinges upon a detector channel chn. The number of detector channels ch counted from the midpoint ct up to a detector channel ch provided with a target collimator 50 whose height is to be determined is represented as N. The height of the target collimator 50 is represented as Ed, and the length in the z-axis direction of a shadowed portion created by the target collimator 50 is represented as S. Obviously from FIG. 3, S:Ed=S+D+N·CL:FD. Therefore, (S+D+N·CL)Ed=FD·S, and hence, (D+N·CL)Ed=(FD−Ed)S. From the equation, the length S can be obtained according to: S=((D+N·CL)Ed)/(FD−Ed). The length S is set so that efficiency of X-ray usage, (1−S/CL), which is defined using the length S, exceeds a predetermined threshold. Since the width CL is constant, the value of efficiency of X-ray usage, (1−S/CL), varies with the length S. For example, since it is undesirable for efficiency of X-ray usage to be reduced by more than 5% by providing the collimator 50, the value of the length S is determined so that 0.95<(1−S/CL)<1 holds when a certain amount of drift D is accounted for. After determining the length S as described above, the height Ed of the target collimator 50 to be determined is obtained from the equation (S+D+N·CL)Ed=FD·S, as Ed=(FD·S)/(S+D+N·CL) when a certain amount of drift D is accounted for. Since the incident angle θ of the X-ray beam 5 on a detecting surface Su is larger on the outer side farther from the midpoint ct, and X-ray beam 5 impinges more slantingly upon the detecting surface Su there, the length S is larger for a collimator 50 having the same height Ed on the outer side. Thus, to securely maintain efficiency of X-ray usage above the threshold by reducing the length S on the outer side, the height Ed of the collimator 50 is preferably smaller with increasing separation from the midpoint ct toward the outside, as shown in FIG. 3. When the collimators 50 are provided as described above, the detector channel chn+1 with a shadow and the detector channel chn without a shadow, for example, have different X-ray detection sensitivity. Efficiency of X-ray usage according to the amount of X-rays impinging upon a detecting surface Su is one of the main factors that dictate the X-ray detection sensitivity in each detector channel ch. Therefore, the calculation/control apparatus 23 in the X-ray CT apparatus 10 corrects the difference in X-ray detection sensitivity between the detector channels ch due to the collimators 50, and then reconstructs tomographic image data. However, since the X-ray detection sensitivity also varies with the amount of drift D of the X-ray focal spot 3, the correction must be made taking the amount of drift D into account. The process of correcting the X-ray detection sensitivity will now be described in detail. To correct the X-ray detection sensitivity, a calibration process is conducted for determining an offset of the X-ray detection sensitivity with respect to a reference value for each detector channel ch. FIG. 4 is a flow chart of an exemplary procedure of the calibration. In the calibration, X-rays are first detected by the rotating section 2 (Step ST1). Since the detection of X-rays at Step ST1 is for the purpose of inspecting the X-ray detection sensitivity in each detector channel ch, the intensity of X-rays emitted from the X-ray source XL is detected by the X-ray detector 70 in the absence of the subject 1. Moreover, the detection need not necessarily be conducted with the rotating section 2 being rotated, and it is sufficient to detect the intensity of X-rays impinging upon the X-ray detector 70 in at least one view. As previously discussed, detected data of the X-ray intensity detected by the X-ray detector 70 is collected by the DAS 20, and sent to the calculation/control apparatus 23. The calculation/control apparatus 23 conducts pre-processing including offset and reference corrections on the detected data sent from the DAS 20 (Step ST2). The offset and reference corrections and other such processing are generally called pre-processing because they are conducted before the data is back-projected by a technique such as backprojection to generate image data. The offset correction refers to a correction of an offset value incorporated into the detected data mainly due to drift of an A–D (analog-to-digital) converter provided in the DAS 20. The reference correction is for correcting variation in the intensity of X-rays emitted from the X-ray source XL. X-rays emitted from the X-ray source XL do not always have the same intensity, and the intensity of the emitted X-rays may vary under some conditions. In such a case, the ratio dact(ij)/dref(j) between detected data dref(j) from a detector channel ch generally referred to as a reference channel, i.e., a detector channel ch upon which X-rays not passing through the subject 1 always impinge even in the presence of the subject 1, and detected data dact(ij) from other detector channels ch, can be used to correct the variation in intensity of the emitted X-rays. The reference channel chR is provided at an end of the X-ray detector 70 in the channel direction, and a plurality of the reference channels chR are arranged in the column direction, as exemplarily shown in FIG. 2. The value dpre of the detected data after the processing up to Step ST2 is compared with a predetermined reference value for each detector channel ch (Step ST3). The reference value is defined as a value obtained from each detector channel ch in the absence of the collimators 50, for example. Then, for example, it may be considered that a value dpre for the detector channel chn shown in FIG. 3 is approximately equal to the reference value, and a value dpre for the detector channel chn+1 is smaller than the reference value due to the influence by the portion shadowed by the collimator 50. To correct the difference in X-ray detection sensitivity among the detector channels ch caused by the presence of the collimators 50 as described above, the calculation/control apparatus 23 creates a sensitivity correction vector based on the value dpre (Step ST4). Specifically, the calculation/control apparatus 23 calculates a value Vt for transforming the value dpre to the reference value for each detector channel ch, and defines a vector in which the values Vt are arranged in the channel direction for each detector channel row 7 as the sensitivity correction vector. The sensitivity correction vector does not need to be created for a detector channel row 7 in which the X-ray detection sensitivity is substantially invariant, regardless of the presence of the collimator 50, and the vector is created at least for detector channel rows 7 having the X-ray detection sensitivity varying by the presence of the collimator 50. As previously discussed, the X-ray detection sensitivity varies with the amount of drift D of the X-ray focal spot 3. Therefore, the calibration process from Step ST1 to Step ST4 is repeated a plurality of times for different amounts of drift D. The calculation/control apparatus 23 then decides whether the calibration process is to be terminated (Step ST5). The calculation/control apparatus 23 repeats Steps ST1–ST4 until the calibration process is executed for a predetermined number of times for different amounts of drift D. Upon completing the calibration process for the predetermined number of times for different amounts of drift, the calibration is terminated. The amount of drift D of the X-ray focal spot 3 varies due to, for example, thermal expansion of components in the X-ray source XL as the temperature of the X-ray source XL changes with use. The value dpre obtained by a reference channel chRn in a certain detector channel row 7, such as the detector channel row 7 containing the detector channel chn in FIG. 3, in which the X-ray detection sensitivity is invariant and constant, is represented as the value drefpn. Moreover, the value dpre obtained by a reference channel chRn+1 in a certain detector channel row 7, such as the detector channel row 7 containing the detector channel chn+1, in which the X-ray detection sensitivity varies, is represented as the value drefpn+1. The amount of drift D can be determined according to the magnitude of the ratio Idx=(drefpn+1)/(drefpn). By using the ratio Idx as an index (argument), a plurality of sensitivity correction vectors for correcting the X-ray detection sensitivity of the detector channels ch in each detector channel row 7 can be obtained according to the indices for that detector channel row 7. FIG. 5 represents the sensitivity correction vectors in one detector channel row 7 as a tri-axial graph. The first axis in the horizontal direction in FIG. 5 represents the channel index i in the detector channel row 7. The second axis in the depth direction represents the value of the ratio Idx. The third axis in the vertical direction represents a corrective value for transforming the value dpre obtained by each detector channel ch in the target detector channel row 7 into the reference value. These corrective values can be arranged in the sequence of the channel index as elements for generating a vector serving as the sensitivity correction vector. A sensitivity correction vector for a ratio Idx that cannot be obtained by the processing of Steps ST1–ST 5 is generated by fitting processing such as interpolation or extrapolation. In FIG. 5, the corrective values corresponding to the detector channels ch only for four ratios Idx are shown by connecting them with line segments as an example, though corrective values corresponding to other ratios Idx can be obtained by fitting processing. Moreover, the number of channel indices i shown in FIG. 5 is merely an example, and data corresponding to a number of corrective values that is the same as the number of the detector channels ch are actually obtained. These sensitivity correction vectors are, for example, stored in a storage device (not shown), such as a memory or hard disk drive, within the console 10B. Now a procedure of tomographic imaging on the subject 1 using the X-ray CT apparatus 10 comprising the X-ray detector 70 provided with the aforementioned collimators 50 will be described hereinbelow with reference to the flow chart shown in FIG. 6. To obtain a tomographic image of the subject 1, projection data of a cross-sectional plane through the subject 1 is first acquired (Step ST10). As previously discussed, the X-ray source XL and X-ray detector 70 are rotated around the axis O by the rotating section 2 to scan the subject 1, whereby projection data of a cross-sectional plane are obtained in a plurality of views. The calculation/control apparatus 23 applies first pre-processing such as offset correction, as in the calibration, to the projection data obtained at Step ST10 (Step ST11). After executing Step ST11, the calculation/control apparatus 23 calculates a ratio Idxr serving as the index for a sensitivity correction vector (Step ST12). The ratio Idxr is calculated using, for example, values drefrn and drefrn+1 in a first view, corresponding to the aforementioned reference channel chRn in which the X-ray detection sensitivity is approximately constant and to the reference channel chRn+1 in which the X-ray detection sensitivity varies, respectively. The calculation/control apparatus 23 uses these values to calculate the ratio Idxr according to Idxr =(drefrn+1)/(drefrn). The calculation/control apparatus 23 reads from the storage device a sensitivity correction vector corresponding to the index obtained by the calculation. The calculation/control apparatus 23 uses the read sensitivity correction vector to correct projection data corresponding to each detector channel ch subjected to the processing at Step ST11 (Step ST13). The calculation/control apparatus 23 corrects the projection data corresponding to each detector channel ch by a calculation of, for example, multiplying a detector channel ch by a corrective value as an element in the sensitivity correction vector, for each detector channel row 7. The value for the corrected projection data is approximately equal to a projection data value obtained by a detector channel ch having approximately the same X-ray detection sensitivity as that in the absence of the collimators 50. The calculation/control apparatus 23 furthermore applies second pre-processing such as beam hardening (BH) correction to the corrected projection data (Step ST14). The beam hardening correction is for correcting a non-linear relationship between the X-ray path length over which X-rays pass through the subject, and detected X-ray intensity, due to a difference in X-ray absorptivity in different materials. After the processing set forth above, the calculation/control apparatus 23 applies filtering processing preparatory for image reconstruction to the projection data obtained at Step ST14 (Step ST15). Steps ST11–ST15 are collectively referred to as a pre-processing stage here because they are preparatory processing for image reconstruction processing. The calculation/control apparatus 23 conducts a calculation for backprojection/image reconstruction using the filtered projection data to generate image data of a predefined cross section through the subject 1 (Step ST16). Moreover, the calculation/control apparatus 23 conducts post-processing, such as rendering, based on the generated image data (Step ST17). The post-processing at Step ST17 provides several kinds of processing, such as, for example, color conversion in the tomographic image, or switching between two-dimensional display and three-dimensional display. A tomographic image based on image data post-processed at Step ST17 is displayed on the display device 25 (Step ST18). As described above, according to the present embodiment, scatter rays are prevented from reaching the detecting surfaces Su in the X-ray detector 70 by providing the X-ray detector 70 with the collimators 50 each extending in the channel direction, arranged in the column direction. Moreover, according to the present embodiment, X-ray detection sensitivity of the detector channels ch in the X-ray detector 70 varies due to the provision of the collimators 50, and considering this, a projection data value corresponding to each detector channel ch is corrected. Thus, a tomographic image of the subject 1 can be produced with substantially only the influence by scatter rays removed. FIGS. 7(a) and (b) are diagrams schematically showing exemplary tomographic images of the subject 1, in which (a) shows a tomographic image Im1A obtained using the X-ray CT apparatus 10 in accordance with the present embodiment, and (b) shows a tomographic image Im1B obtained using a conventional X-ray CT apparatus. As shown in FIG. 7(b), the conventional apparatus without collimators in the column direction of the X-ray detector for preventing impingement of scatter rays is likely to generate a shade Sd caused by scatter rays at, for example, the border between a bone Br and other tissue. Such a shade Sd is clinically undesirable in that the tomographic image Im1B becomes inaccurate and unclear. On the other hand, the present embodiment capable of removing the influence by scatter rays provides the tomographic image Im1A without the shade Sd, as shown in FIG. 7(a). Image quality of the tomographic image Im1A without the shade Sd can be considered as being improved over that of the tomographic image Im1B with the shade Sd. It should be noted that the present invention is not limited to the aforementioned embodiments, and several modifications may be done. For example, there may be provided not only the collimators 50 but also collimators between detector channels ch adjoining in the channel direction. FIG. 8 is a diagram depicting an X-ray detector 77 as viewed in the column direction (z-axis direction), which comprises, in addition to the collimators 50, collimators 55 extending in the column direction at the borders between the detector channels ch adjoining in the channel direction. The collimators 55 are provided on the side of the detecting surfaces Su, and are directed toward the X-ray focal spot 3, for example. By using the X-ray detector 77 comprising such collimators 55, instead of the X-ray detector 70, the influence by scatter rays are more effectively removed and a tomographic image can be obtained with still higher image quality. Moreover, the flow chart shown in FIG. 6 is an exemplary procedure of tomographic imaging, and the index calculation procedure at Step ST12 or the correction procedure at Step ST13 may be executed at any point within the pre-processing stage. Furthermore, while X-rays are employed as the radiation in the embodiment set forth above, other radiation, such as gamma rays, may be employed. Many widely different embodiments of the invention may be configured without departing from the spirit and the scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in the specification, except as defined in the appended claims.
	summary
	description	This is a continuation, under 35 U.S.C. §120, of copending international application No. PCT/EP2003/009209, filed Aug. 20, 2003, which designated the United States; this application also claims the priority, under 35 U.S.C. §119, of German patent application No. 102 46 131.7, filed Oct. 1, 2002; the prior applications are herewith incorporated by reference in their entirety. The invention relates to a fuel assembly for a boiling water reactor. Such a fuel assembly contains a bundle of fuel rods held laterally by spacers and surrounded by a fuel assembly case. There is a foot part at its bottom end, and a top part at its top end. Between the outer side of the spacers and an inner side of the fuel assembly case there is a gap, in order that fuel rods at the edge can also be supplied with cooling water during operation. Studs project from the outer side of the spacers. The width across flats of such a spacer, that is to say its width measured over the studs, is less than the clearance width of the fuel assembly. For reasons of neutron economy, fuel rods, spacers and the fuel assembly case are fabricated from zirconium alloys. Components of zirconium alloys whose texture factor differs from 0.33 exhibit growth during the reactor operation corresponding to the texture (for example as a result of irradiation with neutrons, corrosion influences and so on), which in the case of spacers has the effect that their width across flats increases during use in the reactor. In order to permit disassembly without difficulty in the event of service, the neutron-induced growth is compensated for by a corresponding reduction in the width across flats of the spacers. In the case of a new fuel assembly, there is thus a relatively large gap between the fuel assembly case and the fuel rods and the spacers of a bundle of fuel rods. Added to this is the fact that the central regions of the fuel assembly case, remote from the foot and top part, widen permanently under the temperatures and pressures prevailing during operation, which can be attributed to radiation-induced creep of the zirconium material. The gap present between the spacers and an inner side of the fuel assembly case in the installed state will therefore initially become larger still during operation. Thus, for example on account of different flow conditions, a fuel assembly can deflect laterally and, as a result, come close to an inner side of the fuel assembly case, which results in that the gap assigned to the inner side decreases but the opposite gap is enlarged. The consequence is a change in the thermohydraulic conditions in the region of the relevant fuel rods close to the edge. In the case of the fuel assembly disclosed by U.S. Pat. No. 5,267,291, this is to be prevented as follows: on two mutually adjacent edge webs of the spacers there are studs which project less farther from their outer side than the studs of the respective other two edge webs. In addition, spring elements are fitted to the outer side of the first-mentioned edge webs, are supported on the fuel assembly case and center the fuel assembly therein. Accordingly, the aforementioned gaps all have the same width. It is accordingly an object of the invention to provide a fuel assembly for a boiling water reactor that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which ensures defined mounting in a fuel assembly case and which is improved from a thermohydraulic point of view. With the foregoing and other objects in view there is provided, in accordance with the invention, a fuel assembly for a boiling water reactor. The fuel assembly contains a spacer for laterally holding a bundle of fuel rods, and the spacer has outer walls and flats. A fuel assembly case surrounds the spacer, a width across the flats of the spacer being smaller than a clearance width of the fuel assembly case. Studs project from the outer walls of the spacer and ensure an outer gap between a respective outer wall of the spacer and the fuel assembly case. The spacer is held in an off-center position by a force acting laterally on the spacer such that the outer gap present between the respective outer wall of the spacer assigned to an outer side of a core cell and the fuel assembly case is narrower than an inner gap formed opposite the outer gap and facing a center of the core cell having a control element in the center. The object is achieved in that a spacer is held in an off-center position by a force acting laterally on it or on a fuel assembly such that the outer gap which is present between an outer side of the spacer assigned to the outer side of a core cell and the fuel assembly case is narrower than a gap opposite the gap and facing the center or a control element present there. This ensures that, in the region of a spacer, there are gaps which are defined and can be calculated in advance and which do not change in an unpredictable manner during reactor operation. A core cell is a configuration of four fuel assemblies between which a control element with a cross-shaped cross section is disposed. The fuel rods adjacent to the control element have a higher power density, because of the quantity of water or moderator, which is higher there, than the fuel rods assigned to the outer side of a core cell. They are therefore normally less enriched than the fuel rods on the outer side. By the off-center position according to the invention of the fuel assembly in the fuel assembly case, the cooling in the region of an inner gap is improved by enlarging the cooling cross section, and thus the margin from the boiling transition power (MASL) is increased. In the case of the fuel rods of lower power density located on the outside, although there is a reduction in the coolant throughput, this can be compensated for by an optimized enrichment distribution. The force, which maintains a bundle of fuel rods in it's off-center position is preferably applied by spring elements. However, it is also conceivable for the force to be produced by flow-induced pressure differences. In a preferred embodiment, the spring elements are provided on an outer side of the spacer assigned to an inner gap. This ensures that the opposite outer side of the spacer can come closer to the fuel assembly case than if spring elements, for example like those in a fuel assembly according to U.S. Pat. No. 5,267,291, were to be arranged there. In accordance with a preferred embodiment of the invention, the outer gap contains two outer gaps and both of the outer gaps are narrower than the inner gap formed of two inner gaps. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a fuel assembly for a boiling water reactor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 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 embodiments when read in connection with the accompanying drawings. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a pressure vessel of a boiling water reactor. In each case groups of four fuel assemblies 1 are combined to form a core cell 2. In the figures, for illustrative reasons, only a spacer 3 of one bundle of fuel rods are illustrated; the water channel and fuel rods have been left out. The overall shape of the spacer 3 is in principle arbitrary. In the exemplary embodiment shown, however, the spacer 3 is composed of longitudinal and transverse webs 4, 5 plugged into one another and edge webs 6a-d surrounding the latter. On the longitudinal and transverse webs 4, 5 there are spring elements 7 used to hold fuel rods 30 of which only a few fuel rods 30 are illustrated in FIG. 1. In addition, the spacer 3 has an opening 8 which is disposed off-center and through which a water channel passes. A bundle of fuel rods with its spacer 3 is surrounded by a fuel assembly case 9. The bundle of fuel rods of the core cell 2 is disposed such that their centers or the centers of the spacers 3 respectively assigned to them lie approximately at the corners of a square. Between the bundles of fuel rods and the spacers 3 located at the same vertical level there is an interspace 10, which accommodates a control element 12 of cross-shaped cross section. Between the control element 12 and the fuel assembly case 9 adjacent to it there is a space 13. The inner edge webs 6a, 6b and those adjacent to the control element 12 are provided with, for example, two spring elements 14, which extend away from the outer side 15a of the edge webs 6a, 6b (see FIG. 2). The spring elements 14 are supported against an inner side 16 of the fuel assembly casing 9. The two spring elements 14 of an edge web 6a, 6b are in each case disposed close to a corner 17 of the spacer 3. On the two outer edge webs 6c, 6d, which are assigned to an outer side 18 of a core cell, there are no spring elements, instead only studs 19 on the outside (see FIG. 3). The spring elements 14 press the spacer 3 away from the inner side 16 of the fuel element case 9, in each case with a force extending transversely with respect to the corresponding edge web 6a, 6b. This results in a force component acting diagonally on the spacer 3 in the direction of arrow 20. The result of the force action is that the edge webs 6c, 6d that are free of the spring elements are pressed with their studs 19 against the inner side 16 of the fuel element case 9. Because of the studs, which project from the outer side of the edge webs 6c, 6d, there is a narrow gap 22 between these and the fuel assembly case 9. By contrast, a gap 23 between the outer edge webs 6a, 6b and the fuel assembly case 9 is substantially larger. As compared with a central configuration of the spacer in the fuel assembly case 9, implemented for example by spring elements distributed around the circumference of the spacer 3, in the configuration according to the invention there is a relatively large gap 23 and therefore intensified cooling at the location of greater power density, that is to say for example the rows of fuel rods 24 immediately adjacent to the control element 12. This application claims the priority, under 35 U.S.C. §119, of German patent application No. 102 46 131.7, filed Oct. 1, 2002; the entire disclosure of the prior application is herewith incorporated by reference. Referring to FIG. 2, it can be seen that the inner edge webs 6a and 6b of the spacer 3 are adjacent the inner region 52 of the core cell 2. The gap 23 between the inner edge webs 6a, 6b and the fuel assembly case 9 extends at least from one of the spring elements 14 to another one of the spring elements 14. The inner edge webs 6a, 6b are adjacent the control element 12 and the interspace 10 that accommodates the control element 12. The two outer edge webs 6c, 6d are remote from the control element 12. Referring to FIG. 3, it can be seen that the outer edge webs 6c and 6d are adjacent the outer region 55 of the core cell 2.
	abstract	This invention relates to radioactive, bone-seeking, pharmaceutical methods, compositions and formulations that have a lower impurity profile, a longer shelf life, improved availability and are less expensive to prepare. The compositions of this invention can be conveniently prepared in a timely manner resulting in improved availability and delivery of the drugs to patients.
051134233	abstract	A method and apparatus for increasing the coherence and reducing the emittance of a beam-shaped pulse operates by splitting the pulse into multiple sub-beams, delaying the propagation of the various sub-beams by varying amounts, and then recombining the sub-beams by means of a rotating optical element to form a pulse of longer duration with improved transverse coherence.
	abstract	The invention relates to a sight device (1), in particular a reflector sight or telescopic sight, which sight device has a lighting apparatus (2) for producing or illuminating a target mark, wherein the lighting apparatus (2) comprises an light guide (3) made of photoluminescent, in particular fluorescent material and a radioluminescent light source (7) coupled to the light guide (3), wherein the light guide (3) is designed to receive ambient light and convert said ambient light into photoluminescence light along at least one segment (4) of the longitudinal extent of the light guide, and wherein the absorption spectrum (10) of the photoluminescent material of the light guide (3) and the emission spectrum (9) of the radioluminescent light source (7) in the visible range can both be characterized by a spectral bandwidth and a center wavelength. In order to increase the luminance of the lighting apparatus and thus the visibility of the target mark, the center wavelength of the emission spectrum (9) of the radioluminescent light source (7) is greater than the center wavelength of the absorption spectrum (10) of the photoluminescent material of the light guide (3).
	description	FIG. 1 is a diagrammatic an x-ray system utilizing the lenses of the present invention. The x-ray lens system is generally shown as 20 in this present embodiment and includes an x-ray filter 22, lens 24, a main lens 26, and an extension lens 28. The present invention may be used with only one of these lenses or any combination of these lenses or other lenses defined in this description. An x-ray generator 30 produces x-rays 32 which include direct or coaxial x-rays that are filtered by x-ray filter 22. The x-ray filter 22, which may be a bandpass, highpass or lowpass filter, is comprised of a ring 21 which blocks or absorbs off-axis x-rays that are not reflected by the interior of the lenses and/or do not converge to the focal point 34 of the lens system 20. A filtering medium 23 is placed within the ring 21 of the x-ray filter 22 to filter x-rays entering the lens system 20, bypassing the reflective surfaces of the lens system 20, and traveling directly to focal point 34. Alternatively, the filter 22 may be placed at the exit aperture of a lens system 20 or two filters 22 may be used simultaneously at both the entrance and exit apertures of a lens system 20. The x-rays 32 are collected by the x-ray lens system 20 and focused by the lens system 20 as x-rays 36 which converge to focal point 34. In radiotherapy, a system utilizing the x-ray focusing properties of the present invention can destroy a malignancy with reduced damage to collateral tissue and an energy use in the KeV range rather than the MeV range. This use of lower energy x-rays allows quicker fall-off behind the target tissue and reduced damage to tissue located behind the target tissue. A malignancy or target volume 38 is subjected to the greatest intensity of the focused x-rays 36 when the focal point 34 of the lens system is placed directly upon the malignancy 38. This focusing action also minimizes the radiation exposure of the healthy tissue surrounding the malignancy, decreasing collateral damage to the healthy tissue. The modular nature of the lens system 20 is evidenced by the ease at which the focal length and focal point area is adjusted. The focal length X and focal point 34 area of the x-ray lens system is easily changed by substituting different individual lens components with lenses of the desired aspect combinations. The focusing properties of the present invention also lead to the advantages of having improved flux and resolution in x-ray diffraction or other x-ray applications. The x-ray lenses of the present invention utilize the principles of Bragg reflection and Laue diffraction. FIG. 2 provides a graphical illustration of a simple Bragg reflector. X-ray radiation 40 of wavelength xcex is incident on a crystal or multilayer 42 having lattice or multilayer spacing d. Narrow band or generally monochromatic radiation 44 is than reflected according to Bragg""s Law. Mosaic graphite is the preferred crystal structure which may be utilized as a Bragg reflector to provide a narrow band or generally monochromatized x-ray beam. In other embodiments other crystals or Bragg structures such as multilayers can be substituted within the lens system to reflect radiation using Bragg""s law. Mosaic graphite and other Bragg structures only reflect radiation when Bragg""s equation is satisfied: nxcex=2dsin(xcex8) where n=the order of reflection xcex=wavelength of the incident radiation d=layer-set spacing of a Bragg structure or the lattice spacing of a crystal xcex8=angle of incidence Mosaic graphite was chosen as the preferred x-ray reflecting or diffracting material in the embodiments of the present invention because of its superior performance properties, such as a large reflection angle, large rocking curve width due to the mosaic structure, and high reflectivity. In both Bragg and Laue diffraction, Bragg""s law dictates the reflection and/or diffraction of the incident x-rays. The only difference is in Bragg diffraction the incident and diffracted beam share the same crystal surface, while in the Laue case the incident and diffracted beam use two different surfaces. The former is usually called a xe2x80x9creflection schemexe2x80x9d and the latter is referred to as a xe2x80x9ctransmission schemexe2x80x9d. The structure of the mosaic graphite consists of a regular three dimensional array of atoms which forms a natural diffraction grating for x-rays. The quantity d in Bragg""s equation is the perpendicular distance between the planes of atoms in the mosaic graphite forming the diffraction grating. Mosaic crystal consists of numerous tiny independent crystal regions which are nearly parallel but not quite parallel with one another. When x-rays from an x-ray source strike a reflective surface the incidence angle varies since the point of reflection of various x-rays are at differing distances from an x-ray source. As the incidence angle of x-rays falling upon the mosaic graphite is varied so will the crystal regions reflecting the x-rays. This is caused by the differing orientations of the individual crystal regions within the mosaic graphite. There is not only an incidence angle upon the general surface of the mosaic graphite but individual local incidence angles upon the independent crystal regions. An x-ray beam falling on the mosaic graphite will reflect at a wider incident angle than a perfect crystal because x-rays entering into the graphite at wider incident angles will reach mosaic elements oriented correctly for reflection at that angle. The mosaic graphite reflects over an angular range which depends on the scatter of the mosaic orientations but the range is greater than that of a perfect crystal or multi-layered thin film Bragg reflector. The arrangement of the lattice structure and crystal regions may be varied from slightly ordered to highly ordered depending on the application. For x-rays of differing energy, the Bragg angle is different and mosaicity provides the capability to accept more energy over a wider angular range. In the preferred embodiment, the main parameters of the graphite used in the Bragg reflective lenses of the present invention are: d-spacing d: 3.33 xc3x85 FWHM w: 0.5xc2x0 Reflectivity R.: 50% Density p: 2.25 g/cm3 Attenuation xcexc: 0.175 gxe2x88x921xc2x7cm2 FIG. 3 is a diagrammatic view of the crystal regions 46 in mosaic carbon reflecting x-rays. The reflecting surface 48 of the Bragg lens is curved in a circular manner. This curvature will improve the focusing properties of the lens by keeping the incident angle constant for x-rays that are incident throughout the extent of reflecting surface 48. This ideal reflective surface will allow x-rays 50 generated at point A and incident upon individual crystal regions 46 to be focused at point B. The individual crystal regions 46 are shown slightly out of parallel with respect to each other resulting in the focal point B. The Bragg condition is guaranteed by the following two conditions, the angle made by an incident x-ray and reflected x-ray is constant along the circle and the tiny crystal regions will make correct Bragg angle exits. For crystal with different d-spacings, and different source-focus point a different size circle will be chosen to meet the Bragg angle requirements. In a real application, x-rays might meet proper crystal regions not exactly on the circle due to using flat crystals. This will give a widened beam spot on focal point B. The parallelism and performance of a mosaic crystal reflector is characterized and described completely by its rocking curve width, its inherent reflectivity, and attenuation coefficient. In further embodiments of the present invention, the principle of Laue diffraction/transmission is utilized to direct and focus x-rays. As seen in FIG. 4, incident x-rays 52 penetrate a crystal 54 and a portion of the incident x-rays 52 is diffracted and travels through the crystal 54 along the diffracted direction and exits the crystal 54 as focused x-rays 56. In a Laue lens configured as a ring, x-rays are diffracted at different focusing circles within the crystal. The Bragg angles are different at different point in the crystal volume, which results in an overall wider spectrum than Bragg reflectors. The ideal inner mosaic graphite crystal surfaces and crystal planes of the lenses of the present invention follow the Johansson scheme. As seen in FIG. 5, a bent Johansson crystal 58 is used to reflect and focus x-rays. The bent Johansson crystal 58 will reflect x-rays according to Bragg""s law. The Johansson crystal 58 is made by bending a crystal into a cylindrical surface with a normal radius 2R, and then polishing the reflection surface 60 to a cylindrical surface with radius R. The angle made by each pair of incident rays 62 generated by x-ray source 64 and reflected rays 66 is the same. The lines 68 that connect reflection points 70 to the point 72 on the other side of the circle 74, which is the symmetric point to the source and the focal point, are always equal and bi-partition the angle. Therefore, the curve that is perpendicular to these lines will constitute a Bragg plane, which are the bent 2R crystal planes in this Figure. FIG. 6 is a perspective of the main x-ray lens 26 used in the present invention. The main x-ray lens 26 is cylindrical in form with a hollow interior lined with a graphite layer 76. Preformed or xe2x80x9cbentxe2x80x9d graphite blocks can be bonded together to form the graphite layer 76 on the interior of a lens housing 78. In one embodiment of the present invention four graphite blocks, each covering a quarter of the interior of the x-ray lens 26, are mounted on the interior of the x-ray long 26 to form a curved interior surface. In an alternate configuration graphite can be grown by deposition process inside the lens housing 78 to form a reflection layer. In the preferred embodiment of the present invention, as seen in FIG. 6, the mosaic graphite layer 76 will approximate the reflecting surface of the Johansson Crystal illustrated in FIG. 5. The surface of the interior of the main x-ray lens 26 will be curved in a circular manner relative to the housing and incident x-rays 75. The term circular is used when referring to a Gross section or two-dimensional picture of the lens system, but a person of ordinary skill in the art would recognize that in three dimensions the lenses would be curved relative to the housing. This curving results in a smaller focal point area, as the mosaic graphite crystal will be aligned in the ideal form of the Johansson crystal to improve the focusing properties of the main x-ray lens 26 FIG. 7 is a lengthwise cross sectional view of an alternate embodiment of the main Bragg reflective lens 26xe2x80x2 of the present invention focusing x-rays. The main Bragg reflective lens 26xe2x80x2, as shown by the drawing, has a graphite layer 76xe2x80x2 that is not inclined or angled, rather it is substantially concentrically flat relative to the cylindrical housing of the main lens 78xe2x80x2 relative to incident x-rays 75xe2x80x2. The barrel or interior surface of the main lens 26xe2x80x2 therefore has generally a constant inner diameter throughout its full length. The flat reflecting surface of the graphite layer 76xe2x80x2 is easier to fabricate than the curved graphite surface 76 shown in FIG. 6 and will roughly approximate the surface of a the Johansson crystal shown in FIG. 5. The focusing properties of flat reflecting surface of the graphite layer 76xe2x80x2 will have more aberration than the curved graphite surface 76, shown in FIG. 6 of the leading to a larger focal point 79xe2x80x2. FIG. 8 is a cross sectional view of a modular x-ray lens system of the present invention. The lens system 20 can be constructed from a plurality of lens components. In the present embodiment, the lens 24 is coupled to the main lens 26 which further couples to an extension lens 28 to focus x-rays. The lenses may be coaxially physically coupled by threaded members, flanges or other connection devices known in the art. The lenses are preferably in a cylindrical configuration. The inner mosaic graphite crystal surfaces 80, 76 and 82 of these lenses follow the Johansson scheme shown in FIG. 5 when adjacent to each other. The mosaic graphite surfaces have been configured to approximate the ideal Johansson crystal reflecting shape. As discussed previously, the term circular is used when referring to a cross section or two dimensional picture of the lens system, but a person of ordinary skill in the art would recognize that in three dimensions the lenses would be curved. The modularity of the system is also beneficial. The focal point and x-ray intensity of the present invention can be varied by simply arranging, removing, or adding lenses with various reflecting characteristics. Multiple combinations of individual lenses can be configured to meet almost any application. Referring to FIG. 9, the mosaic graphite layer 80xe2x80x2 of lens 24xe2x80x2 is sloped in linear fashion (conical in three dimensions), the mosaic graphite layer 76xe2x80x2 of main lens 26xe2x80x2 is flat (cylindrical in three dimensions), and the mosaic graphite layer 82xe2x80x2 of extension lens 28xe2x80x2 is also sloped in linear fashion (conical in three dimensions) opposite to that of mosaic graphite layer 80xe2x80x2. These lenses alone do not possess a curved shape but when placed together approximate the curved circular shape of the ideal reflective surface of the Johansson crystal with their angular and flat surfaces. This conical system is also modular and lenses may be added or removed to improve performance. The main performance of an x-ray lens is its collecting and transmitting capability for x-rays. It can be described by throughput which is defined as the solid angle from the source, which contains the same amount of photons the lens delivers to the focal point. If we define a solid angle which extends 1xc2x0 in both directions, as a unit for the throughput, this unit will be equal to: unit ⁢ xe2x80x83 ⁢ throughput = ∫ 89.5 ⁢ xc2x0 90.5 ⁢ xc2x0 ⁢ sin ⁢ xe2x80x83 ⁢ θ ⁢ xe2x80x83 ⁢ ⅆ θ ⁢ ∫ 0 0.01745 ⁢ xe2x80x83 ⁢ ⅆ φ = 3.05 xc3x97 10 - 4 ⁢ xe2x80x83 ⁢ strad All Bragg reflective lenses in this section will be estimated in this unit. The parameters of the main lens 26xe2x80x2 are: Inner diameter: 25 mm Length: 115 mm Source-lens center distance: 400 mm Lens center-focus distance: 400 mm Capture angle: 1.70xc3x9710xe2x88x923 strad Focal spot size: 2-4 mm Throughput 2.78 The wavelength of an x-ray at 60 KeV is calculated from the following formula: λ = 12.4 E ⁡ ( keV ) = 12.4 60 = 0.207 ⁢ xe2x80x83 ⁢ Angstroms The Bragg angle is: θ = sin - 1 ⁢ ( λ 2 ⁢ d ) = sin - 1 ⁢ ( 0.207 2 xc3x97 3.33 ) = 1.779 ⁢ xc2x0 The capture angle will be determined by: Δ ⁢ xe2x80x83 ⁢ Ω = ∫ 1.529 ⁢ xc2x0 2.029 ⁢ xc2x0 ⁢ sin ⁢ xe2x80x83 ⁢ θ ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = 1.70 xc3x97 10 - 3 ⁢ xe2x80x83 ⁢ strad In the case of the main lens 26xe2x80x2, the throughput is equal to the capture angle multiplied by the average reflectivity. Therefore the throughput is 8.5xc3x9710xe2x88x924 strad. In the unit defined above, the throughput of our lens 26xe2x80x2 will be 2.78. The parameters of the lens 24xe2x80x2 are: Inner diameter of the exit: 25 mm Inner diameter of the entrance; 23.5 mm Length: 86.5mm Source-lens center distance: 299 mm Lens center-focus distance: 501 mm Capture angle: 2.18xc3x9710xe2x88x923 strad Focal spot size: 4-10 mm, depending on source size Throughput 3.57 The capture angle will be determined by: Δ ⁢ xe2x80x83 ⁢ Ω = ∫ 2.029 ⁢ xc2x0 2.529 ⁢ xc2x0 ⁢ sin ⁢ xe2x80x83 ⁢ θ ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = 2.18 xc3x97 10 - 3 ⁢ xe2x80x83 ⁢ strad As discussed above, the throughput is equal to the capture angle multiplied by the average reflectivity. Therefore the throughput is 1.09xc3x9710xe2x88x923 strad and in the unit defined above, the throughput of the lens 24xe2x80x2 will be 3.57. The lens 24xe2x80x2 will give a large throughput, but will generate a larger focal spot. The parameters of the extension lens 28xe2x80x2 are: Inner diameter of the exit: 23.5 mm Inner diameter of the entrance: 25 mm Length: 86.5 mm Source-lens center distance: 501 mm Lens center-focus distance: 299 mm Capture angle: 1.22xc3x9710xe2x88x923 strad Focal spot size: depends on source size Throughput 1.97 The capture angle will be determined by: Δ ⁢ xe2x80x83 ⁢ Ω = ∫ 1.026 ⁢ xc2x0 1.526 ⁢ xc2x0 ⁢ sin ⁢ xe2x80x83 ⁢ θ ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = 1.22 xc3x97 10 - 3 ⁢ xe2x80x83 ⁢ strad The throughput is 0.61xc3x9710xe2x88x924 strad and in the unit defined above, the throughput of lens 28xe2x80x2 will be 1.97. The extension lens 28xe2x80x2 has finer focus and larger convergent angle. The intensity distribution and throughput of a particular combination of lenses can be calculated based on source information, source projection size, intensity distribution, etc. In further embodiments of the present invention, Laue diffraction/transmission lenses are utilized to direct and focus x-rays. Referring to FIG. 10, a Laue lens 86 of the present invention is illustrated. Incident x-rays 84 penetrate the Laue lens or crystal 86 (in a ring configuration) and a portion of the x-rays 84 is diffracted and travels through the lens 86 along the diffracted direction and exits the lens 86 as focused x-rays 88. In Laue diffraction, x-rays are diffracted at different focusing circles within the crystal. The Bragg angles are different at different points in the crystal volume, which results in an overall wider spectrum than Bragg reflectors. The x-rays 84 are reflected from each lattice layer and directed towards a focal point 90. The distance between the source 92 and the lens 86 is f1 and the distance between the lens 86 and the focal point 90 is f2. The length of the lens is L. The inner diameter of the Laue lens 86 is R1 and the outer diameter is R2. In the case where f1 is not equal to f2, the direction of the atomic planes of the Laue lens 86 will need to change along the diameter direction. Otherwise, the x-rays will not be reflected to the desired focal point. With f1=f2, the lens will be a flat ring instead of a tilted ring with varying atomic planes. Following are two designs; one has symmetric design, and the other has asymmetric design. They have the same working distance and different focal spot size. The main reason for the asymmetric design is to conserve materials and reduce the overall dimension of the system. In the symmetric design, the performance parameters of the graphite for Laue reflection are the same as for Bragg reflection, except for the reflectivity. As measured recently by Applicants, it is about 18% around 60 KeV. d-spacing d: 3.33 ◯ FWHM w: 0.4 (24 arc minutes) Laue reflectivity R: less than 18% Density xcfx81: 2.25 g/cm3 Attenuation xcexc: 0.175 gxe2x88x921xc2x7cm2 The following is a particular design of a Laue lens 86 for the performance estimation. The main parameters of the lens 86 are listed below: Inner diameter: 16.3 mm Outer diameter: 32.6 mm Length: variable Source-lens center distance: 350 mm Lens center-focus distance: 350 mm The inner edge of the Laue lens 86 is tuned to work at 80 KeV; and the outer edge is tuned to work at 40 KeV. The band pass at each point is given by Δ ⁢ xe2x80x83 ⁢ E = E ⁢ xe2x80x83 ⁢ cos ⁢ xe2x80x83 ⁢ θ · Δ ⁢ xe2x80x83 ⁢ θ sin ⁢ xe2x80x83 ⁢ θ At the position where the incident angle xcex8, the energy of the x-rays which satisfy the Bragg law is E = 12.4 2 ⁢ d ⁢ xe2x80x83 ⁢ sin ⁢ xe2x80x83 ⁢ θ Therefore the band pass as a function of q can be written as Δ ⁢ xe2x80x83 ⁢ E = 12.4 ⁢ cos ⁢ xe2x80x83 ⁢ θ · Δ ⁢ xe2x80x83 ⁢ θ 2 ⁢ d ⁢ xe2x80x83 ⁢ sin 2 ⁢ θ where xcex94xcex8 is the rocking curve width. The capture angle will be determined by, Δ ⁢ xe2x80x83 ⁢ Ω = ∫ θ 1 θ 2 ⁢ sin ⁢ xe2x80x83 ⁢ θ · xe2x80x83 ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ where xcex82 is the incident angle at the outer edge and xcex81 is the incident angle at inner edge. θ 1 = sin - 1 ⁡ ( 12.4 80 ⁢ 1 2 xc3x97 3.33 ) = 1.33 ⁢ xc2x0 θ 2 = sin - 1 ⁡ ( 12.4 40 ⁢ 1 2 xc3x97 3.33 ) = 2.67 ⁢ xc2x0 Δ ⁢ xe2x80x83 ⁢ Ω = ∫ θ 1 θ 2 ⁢ sin ⁢ xe2x80x83 ⁢ θ · ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = 5.13 xc3x97 10 - 3 ⁢ xe2x80x83 ⁢ sterad . The efficiency of the lens 86 can be written as Efficiency = ∫ θ 1 θ 2 ⁢ R · Δ ⁢ xe2x80x83 ⁢ E · sin ⁢ xe2x80x83 ⁢ θ · ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = ∫ θ 1 θ 2 ⁢ R ⁢ xe2x80x83 ⁢ 12.4 ⁢ cos ⁢ xe2x80x83 ⁢ θ · Δ ⁢ xe2x80x83 ⁢ θ 2 ⁢ d ⁢ xe2x80x83 ⁢ sin ⁢ xe2x80x83 ⁢ θ ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ where R is 0.18 and xcex94xcex8=0.4xc2x0=0.00698 Rad. Efficiency = 0.00234 ⁢ ∫ 1.33 ⁢ xc2x0 2.67 ⁢ xc2x0 ⁢ cos ⁢ xe2x80x83 ⁢ θ sin ⁢ xe2x80x83 ⁢ θ ⁢ xe2x80x83 ⁢ ⅆ θ ⁢ ∫ 0 2 ⁢ π ⁢ xe2x80x83 ⁢ ⅆ φ = 0.021 Throughput ≈ Efficiency 3.05 xc3x97 10 - 4 · 40 ≈ 0.82 In the unit xe2x80x9cEffective solid anglexe2x80x9d unit, the throughput should be xcex94xcexa9xe2x80x2≈8.2xc3x9710xe2x88x925 assuming the voltage setting is 120 kV. The performance summary is: Capture angle: 5.13xc3x9710xe2x88x923 strad Focal spot size: xcx9c3 mm (depends on fabrication accuracy) Throughput: 0.82 Effective solid angle: 8.2xc3x9710xe2x88x925 The asymmetric lens design shown in FIG. 12 can save material and shorten assembly time. However, as discussed above, theoretically the tilting angle of each layer 94 is different. In practice, it can be approximated by limited number of crystal layers. Each layer 94 is made of whole piece of crystal. Therefore the tilting angle of the crystal plane is the same within each layer 94. This particular lens 100 design includes three concentric layers 94 (rings) having a thickness of 2 mm in the preferred embodiment. The inner radius of the lens is 5.4 mm, while the outer radius of the lens is 11.4 mm. Each lens layer 94 has a conical configuration. The main parameters of this design are given in Table 1. Referring to FIG. 13, a further embodiment of the present invention is shown utilizing Laue reflection to focus x-rays. An x-ray source 92xe2x80x2 directs x-rays 84xe2x80x2 to the lens or crystal 86xe2x80x2 where some of the x-rays 88xe2x80x2 are diffracted and focused and transmitted x-rays 96 exit the crystal without being diffracted. Beam stopper 98 blocks these transmitted x-rays 96. Coaxial x-rays 102 will be filtered by x-ray filter 22xe2x80x2 similar to the previously described x-ray filter 22. A cross section of a combination Laue and Bragg lens system is illustrated by FIG. 14. The x-ray source 92xe2x80x3 directs a portion of the x-rays 84xe2x80x3 to a Bragg reflective surface 104, preferably comprised of mosaic graphite crystal, which reflects generally monochromatic x-rays to the focal point 90xe2x80x3. A portion of the x-rays 84xe2x80x3 also are directed to the graphite crystal 86xe2x80x3 where some of the x-rays 88xe2x80x3 are diffracted and focused to a focal point 90xe2x80x3. Transmitted x-rays 96xe2x80x2 which travel through the crystal 86xe2x80x3 are incident upon a second Bragg reflective surface or lens 106 configured to focus the transmitted x-rays 96xe2x80x2 to focal point 90xe2x80x3. This configuration of multiple Bragg and Laue lenses increases the flux concentrating power of the combination lens system. X-rays which were previously occluded or blocked ore now conditioned and directed towards focal point 90xe2x80x3. The graphite reflecting and diffraction layers of the x-ray lenses of the present invention may be formed by a variety methods including but not limited to direct growth on a lens housing and the bending of a generally flat graphite sheet. The bending process will allow the creation of a conical graphite lens at room temperature. Referring to FIGS. 15-17, in one embodiment of the present invention a generally conical lens is formed by the bending of four identical plates 110 of graphite, each bent plate 110 representing a quarter of the lens, i.e. ninety degrees. The bent plates 110 are assembled in a housing to create the complete conical lens. The quality of bending will directly affect the performance of a graphite lens since the positive stress (compressing force) along the layer direction during bending will damage the mosaicity of the graphite. For example, as shown in FIG. 15, there are three different layers 112 of stress if a graphite lens is bent without a supporting structure. The central layer 114 undergoes no stress during bending. Below and above this central layer the graphite layers 116 will experience negative and positive stresses. The magnitude of the stress is linearly proportional to the distance from the central layer 114 and the length of the graphite plate 110. Damage to the mosaicity of the graphite is directly related to positive stress. In order to minimize the damage to the graphite plate 110 during the bending procedure, three methods of bending may be used. In the first method, since a shorter graphite plate will experience lesser stress during the bending process, several bent graphite plates 110 can be used to form a complete circle as seen in the previous embodiments of the invention. The number of graphite plates 110 to be segmented depends on the radius of the graphite plate 110, thickness of the graphite plate 110 and the mechanical properties of the graphite plate 110. In the second bending method, as shown in FIG. 16, a reinforcement plate 118 is introduced to shift the zero-stress layer to the front surface of the graphite plate 110. In the preferred embodiment, the reinforcement plate 118 is comprised of a piece of transparent mylar sheet glued or affixed onto the front surface of the graphite sheet 110 before bending. The reinforcement plate 118 is removed after bending in order to expose the front surface of the graphite plate 110 to the environment. In the third method, as seen in FIG. 17, two guiding plates 120 and 122 are used to guide the graphite plate 110 for uniform bending. In the third method shown in FIG. 17, a conical rod 109 is placed on the inner guiding plate 120 and the graphite plate 110 is sandwiched by inner guiding plate 120 and outer guiding plate 122. The bending forces are applied to the graphite plate 110 through the guiding plates 120 and 122 so that the graphite plate 110 will form along the conical rod 109 and assume the shape of the conical rod 109. There are two methods for lens assembly to be used in the present invention. FIG. 18 shows a first method of lens mounting where individual bent graphite lens segments are assembled into a complete lens. The axis 128 of a lens holder 126 defines the axis of the lens system. The x-ray camera 130 is positioned at the focal point 132. The position and the angles of an individual bent graphite plate 134 are adjusted such that the reflected beam is focused on the focal point 132. The bent graphite plate 134 is fixed to the holder 126 after the alignment. All remaining graphite plate segments are mounted onto the holder 126 with this procedure. Referring to FIG. 19, another method of lens assembly using a conical ring 152 and a conical rod 150 formed with the desired conical angles is illustrated. All bent graphite plates 154 are assembled simultaneously in this single ring lens method. One or more spacers are needed to fill the gap caused by different conical angles between layers for a multi-layer lens system. The inner rod 150 and the spacers are made from a material with less x-ray absorption than the bent graphite plates 154 and enough mechanical strength and chemical stability to withstand the bending forces generated by the conical rod 150. It is to be understood that the invention is not limited to the exact construction illustrated and described above, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
	description	The present invention relates to the inspection of pipes, and more particularly, to a device and/or method of using x-rays or gamma rays transmitted through a pipe and collected on the other side of the pipe in a digital detector array to determine if there are defects in the pipe. Pipelines are commonly used to transport material such as gas, oil, slurry or similar substances over long distances. Such pipelines are normally made out of metal and are commonly joined together with welds. In refineries, pipelines are used to transport material from one portion of the refinery to another. The pipeline may (or may not) be covered with insulation. Such pipelines may corrode and, if the corrosion is not detected early enough, the pipelines may start to leak. If the leak is not detected early, catastrophic results may occur, including fires and/or explosions. Preferably, the corrosion is detected before a leak ever occurs. Non-destructive testing, including the use of x-rays or gamma rays penetrating the pipeline, is used to determine if a pipeline has defects therein as may typically be caused by corrosion. U.S. Patent Publication No. US 2012/0201347 A1, published on Aug. 9, 2012 by Prentice et al. and assigned to Shawcore Ltd. shows a method and apparatus for inspecting pipelines to determine if there are any defects in a pipeline. However, the Prentice patent is difficult to install and requires access to the entire circumference of the pipeline. If a pipeline is in a refinery and is supported on support beams, the Prentice invention cannot inspect the pipe where the pipe touches the support beam. In pipelines, if the pipeline is buried, non-destructive testing of the buried pipeline is normally made by sending a pig through the pipeline. The pig is typically made up of (a) a drive package, (b) a flux loop that does the sensing and (c) a recorder package. Using such a pig, the entire Trans Alaska Crude Oil Pipeline was tested in 1997. However, for many pipelines, especially in refineries or processing plants, a pig cannot be run through the pipeline. Also, many of the pipelines are covered with insulated material which prevents direct access to the pipeline. The purpose of the non-destructive testing is to use a non-invasive technique to determine the integrity of a pipe or quantitatively measure any corrosions or defects in the pipe. Non-destructive testing inspects and measures without doing harm to the pipe. There are many different ways of non-destructive testing, including, but not limited to, (a) acoustical emissions, (b) ultrasonic, (c) eddy current, (d) magnetic measurements, (e) microwave, (f) flux leakage or (g) x-ray. The use of x-rays or gamma rays is one of the more common techniques for non-destructive testing. In the use of x-ray or gamma ray technology for non-destructive testing, the pipe being tested is placed between the radiation source and a detector. The less radiation that reaches the detector, the better the pipe. The more radiation that reaches the detector, the more wear or corrosion in the pipe. In industrialized countries such as the United States, many refineries or processing facilities were built years ago. Over time, corrosion or erosion can cause the pipes in the plant to wear thin and eventually leak. If a pipe leaks, depending upon what is being moved through the pipe, the leak can cause catastrophic results. The detection of a thin section of pipe before it leaks can be very critical. The use of non-destructive testing for pipelines has become so common that standards have been developed by ASTM International. A collection of ASTM standards under “Radiology (X and Gamma) Method” have been developed. One of the entities that has performed non-destructive testing on insulated pipes in the past is IHI Southwest Technologies, Inc. located in San Antonio, Tex., assignee of this invention. IHI has developed digital radiograph tools for detecting internal and external corrosion in insulated piping. Generally, a radiation source will create a radiation beam that penetrates a pipe under test. The radiation beam will penetrate not only the pipe, but also insulation there-around. A detector array is located on generally the opposing side of the pipe being inspected using a radiation source. In this manner, the detector array can determine if there is any corrosion and the severity of the corrosion. However, the prior systems developed by IHI were very complex and hard to move along a pipe being inspected to give good results. Also, dead zones would occur that were not being penetrated by the radiation. Because of the difficulty in installation and maneuverability of the prior digital radiographic imaging by IHI, it was difficult to eliminate the dead zones. The prior developed digital radiographic tool requires a lot of time to install and operate. It is an object of the present invention to provide for digital radiographic imaging of pipes. It is another object of the present invention to provide a simplified, easy to use, structure for a digital radiograph tool that can be used for inspection of pipes. It is yet another object of the present invention to provide a method and apparatus for using a digital radiograph tool for the inspection of pipes, particularly pipes that are insulated. It is still another object of the present invention to provide an apparatus and method for the inspection of pipes using x-rays or gamma rays, which x-rays or gamma rays after passing through a pipe being inspected are detected and collected in a digital detector array. After processing the images received in the digital detector array, a determination of defects, location of defects, and severity of the defects is made. A radiation source of x-rays or gamma rays is projected through a pipe under test. As the radiation source is moved along the pipe, a digital detector array is also moved along the pipeline, but on an opposing side from the radiation source. The amount of radiation that hits the digital detector array determines, after processing, if there is corrosion or other defects at predetermined points along the pipe. The more of the radiation signal that passes through the pipe, the greater the probability is of a defect in the pipe, such as corrosion. The stronger the signal reaching the digital detector array, the greater the probability of a defect. The digital radiograph tool of the present invention has a track assembly attached to the pipe being inspected. On the track assembly is mounted a car assembly which has attached thereto an arm assembly. On the opposite end of the arm assembly is a linear digital array that is located adjacent to the pipe being inspected. Also connected to the car assembly is a collimator assembly which is located as close as possible to the opposing side of the pipe being tested from the linear digital array. By making the arm assembly expandable and the collimator assembly adjustable, different size pipes can be accommodated. Also, the collimator assembly, track assembly, car assembly and linear digital array can be adjusted on the pipe as necessary to overcome obstructions that may be adjacent to (or touching) the pipe being inspected. By keeping the digital radiographic tool small and fully adjustable, it is much easier to inspect pipes with a minimum of cost and personnel. Referring now to FIGS. 1, 2 and 3 in combination, a pipe 10 is being inspected by a digital radiographic tool 12. The digital radiographic tool 12 has a track assembly 14 with a drive car 16 mounted thereon. The drive car 16 can move back and forth along the track assembly 14. Attached to one side of the drive car 16 is an arm assembly 18. On the distal end of the arm assembly 18 is mounted a linear digital array 20. On the opposite side of the drive car 16 from the arm assembly 18 is attached the collimator assembly 22. The drive car 16 of the digital radiographic tool 12 moves back and forth along pipe 10 on the track assembly 14. As the drive car 16 moves back and forth, it carries the collimator assembly 22 which generates x-rays or gamma rays projected towards the pipe 10. On the opposite side of the pipe 10 from the collimator assembly 22, the x-rays or gamma rays are collected in the linear digital array 20. Referring now to FIG. 4, a pictorial block diagram of the pipe 10 being inspected by a digital radiographic tool 12 is shown. The digital radiographic tool 12 includes the arm assembly 18 and the collimator assembly 22. Power is supplied to the digital radiographic tool 12 by 115V power supply 24 which connects to a power supply and control box 26 via 115 VAC power line 28. Simultaneously, the 115V power supply 24 supplies power to a user laptop 30 via power line 32. The power supply and control box 26 has a joy stick 34 connected to a stepper motor 36 within the drive car 16 (see FIGS. 1, 2 and 3) via drive signal connection 38. The stepper motor 36 provides a 75V drive signal 40 to stepper motor 42. The stepper motor 42 through a gear box 44 drives gears 46 that mechanically connect with track assembly 14. As the drive car 16 (see FIGS. 1, 2 and 3) is driven along track 14, the collimator assembly 22 emits x-rays (or gamma rays) 48 which penetrate pipe 10. The x-rays 48 that penetrate the pipe 10 are then collected by the linear digital array 20. The signals collected by the linear digital array 20 are fed via Ethernet data connection 50 to the user laptop 30. From the laptop 30, USB data connection 52 connects to power supply and control box 26. Also, the linear digital array 20 receives its power from power supply and control box 26 via power connection 54. While many different types of software can be used, Applicants have found that iX-Control by Shaw Pipeline Systems to be a good software to use. Using the iX-Control software, the user laptop 30 can give the commands to the power supply and control box 26 to move the digital radiographic tool 12 a certain distance along pipe 10 and it will occur. By having the collimator assembly 22 emit x-rays 48 as the digital radiographic tool 12 is moved along the track assembly 14, radiated signals will be detected by the linear digital array 20. The user, through the user laptop 30, will set the start point to determine the distance of movement and speed while recording data. The recorded data will indicate whether pipe 10 does (or does not) have defects therein such as would be caused by corrosion. Even if the pipe 10 is surrounded by insulation, the x-rays 48 will penetrate the insulation and the pipe 10 sufficient to give a table recording or a pictorial recording as illustrated in the user laptop 30. If an emergency stop is necessary, an emergency stop button 56 is provided on the power supply and control box 26. Referring now to FIGS. 5(a), (b), (c) and (d), the track assembly 14 will be explained in more detail. Track assembly 14 is made up of modular sections 58 and 60 (see FIG. 5c). As many more sections as may be necessary can be used. Applicants have found that section links of 2 ft. and/or 4 ft. to be ideal. The modular sections 58 and 60 are aligned by alignment pins 62 at each end of the linear rails 64. Opposing ends of the linear rail 64 from the alignment pins 62 have holes therein (not shown) to receive the alignment pins 62. The modular sections 58 and 60 are held together by latch 66. The linear rails 64 are mounted on a track frame 68. Contained within the track frame 68 is a gear rack 70 for meshing with a gear as will be subsequently described. On each end of the modular sections 58 and 60 are located idle roller wheels 72. The idle roller wheels 72 may be held on the track frame 68 by any conventional means such as by bearings and axles. Each of the modular sections 58 and/or 60 are held to the pipe 20 by tie-downs 75 that extend through tie-down slots 74 and around pipe 10 (see FIGS. 1-4). Referring now to FIG. 9 in conjunction with FIGS. 5(a), (b), (c) and (d), a bottom view with the latch 66 is illustrated. FIG. 9 is a cross-sectional view of FIG. 5(b) along section lines 9-9. The latch 66 is pivotally mounted on pivot pin 76. If a user presses release button 78, the latch 66 will be pivoted about pivot pin 76 so that it disengages from latch stop 80. The idle roller wheels 72 are shown threadably connected to the track frame 68 by wheel screws 82. Referring now to FIGS. 6(a)-(e), the drive car 16 will be discussed in detail. The drive car 16 has a stepper motor 42 that connects through a coupler 82 to drive the worm 84 that will mesh with worm gear 86 (see FIG. 6e). The worm gear 86 is connected by drive shaft 88 to the spur gear 90. Spur gear 90 meshes with the gear rack 70 (shown in FIGS. 5(a), (c) and (d)) to drive the entire drive car 16. Power for the stepper motor 42 is received through the drive signal connection 38 connecting through the drive signal input 92. Attached to the top of the car body 94 is the stepper motor driver 36. A waterproof cover 96 seals the stepper motor driver 36 inside of car body 94. Front cap 98 enclosed the front of car body 94. Pin holes 100 and 102 extend through car body 94 to receive removable pins 104 and 106, respectively, there through. Removable pin 104 and 106 are spring-loaded to be removed upon pushing end buttons 108 or 110, respectively (see FIGS. 6d and 6e). T-slots 112 are formed on both sides and in the top of the car body 94. The T-slots 112 allow T-bolts (not shown) to be inserted therein on which items can be attached to the drive car 16. For example, the stepper motor driver 36 is contained in stepper motor driver housing 114 by means of T-slots 112 in the car body 94, which T-slots are located directly below the stepper motor driver housing 114. Referring to FIG. 6c, a linear bearing chassis 116 is shown disconnected and below from the car body 94. The linear bearing chassis 116 is connected to the car body 94 by removable pins 104 and 106 extending through pin holes 100 and 102, respectively (see FIG. 6d). The spur gear 90 extends below the drive car 16 as is illustrated in FIG. 6b. Hence, the spur gear 90 meshes with the gear rack 70 of the track assembly as shown in FIGS. 5a, c and d. The bottom of the linear bearing chassis 66 has linear bearings 118 mounted there below. The linear bearings 118 receive the linear rails 64 (see FIGS. 5a, b, c and d and FIG. 6d) therein. To reduce friction between the linear bearings 118 and the linear rail 64, the linear bearings 118 have bearing liners 120 therein. Referring now to FIGS. 7a-d, the arm assembly 18 is shown in more detail. The arm assembly 18 has a radial arm plate 122 on either side thereof. In FIGS. 7a, b and c, the arm assembly 18 is fully collapsed. In FIG. 8d, the arm assembly 18 is fully extended with an intermediate telescoping T-slot frame 124 and an upper telescoping T-slot frame 126. The intermediate telescoping T-slot frame 124 is held in position by thumb screws 128. The upper telescoping T-slot frame 126 is held in position by thumb screws 130. On the upper end of the arm assembly 18, a T-slot clamp 132 may be pivoted by loosening clamping L-handles 134. By loosening clamping L-handles 134, the T-slot clamp 132 may be pivotally adjusted (see FIG. 7b). At the bottom of the arm assembly 18 and mounted between radial arm plates 122 is the linear digital array 20. The linear digital array 20 has an Ethernet data connection 50 and a power connection 54. Connected in the T-slot clamp 134 is the T-slot mount 136 of the collimator assembly 22 (see FIGS. 8a and b). The first angle adjustment 138 of the collimator assembly 22 is provided by loosening clamping L-handle 140. Held in position by first clamping L-handle 140 is a first collimator arm 142 and a second collimator arm 144, on either of which can be mounted collimator housing 146. Thumb screw 148 secures the collimator housing via slot 150 on the second collimator arm 144. The thumb screw 148 allows for linear adjustment 152 of the collimator housing 146. Also, the collimator housing 146 could be mounted in slot 154 of first collimator arm 142. A second angle adjustment 156 is provided between first collimator arm 142 and second collimator arm 144 by a second clamping L-handle 158. Inside of the collimator housing 146 is located the collimator 160. A shim slot 162 is also provided if minor adjustments to the collimator 160 need to be made. By use of the arm assembly 18 as described in FIGS. 7a-d and the collimator assembly 22 as described in FIGS. 8a and b, the adjustability of the digital radiographic tool 12 is illustrated. This adjustability feature allows either the collimator 160 or the linear digital array 20 to be adjusted to reach under and/or around pipe supports. Due to the adjustability features, various diameter pipes can be accommodated. The adjustability features of the digital radiographic tool 12 allow a single person to operate the tool and to inspect a greater percentage of the pipe than prior inspection devices. Referring now to FIG. 10, connection of the stepper motor 42 through coupler 82 to the worm 84 is illustrated in more detail. The worm 84 meshes with the worm gear 86 mounted on drive shaft 88. As the worm 84 turns, the worm gear 86 also turns and rotates drive shaft 88 on which spur gear 90 is also mounted. The turning of the spur gear 90 which meshes with the gear rack 70 (see FIG. 2), moves the drive car 16 and the entire digital radiographic tool 12 along the track assembly 14.
	summary
	description	This invention involves radioactive waste disposal in deep permanent ice. Properly carried out, it has the advantage of isolating the high level radioactive waste from the biosphere in remote areas, far from human habitation. The isolation from the environment can last for sufficiently long to ensure that the ingestion hazard index posed by the waste is no more than that associated with the uranium ore that it originated from. Furthermore, disposal in deep permanent ice provides for relatively easy placement of the radioactive waste in its ultimate repository by letting it melt its way to the bottom, while making it exceedingly hard to retrieve from glacial depths as the ice will refreeze over it. It was mentioned above that the hazard index for fission products, after separation from the actinides, declined to the same value as that of natural uranium in a time span of the order of a thousand years. Reprocessing on such a basis leaves less of a radioactive legacy for future generations than the alternative of not reprocessing. Such a process encourages use of nuclear power with a simultaneous suggestion of the means of ultimate disposal of radioactive waste. Recent drillings in the central Greenland icecap have revealed a stability that has a time scale of a hundred thousand years. Encapsulating radioactive waste, preferably in solid form, in such amounts and in sufficiently strong and corrosion-resistant containers of such size that the heat from the radiation should suffice to melt the ice at a rate which brings them relatively quickly to the bottom, is possible. After about 800-1000 years the waste will be no more hazardous than the natural uranium which undoubtedly is to be found in many places underneath the ice cap. Antarctica would be even more suitable for disposal because of its remoteness from any human habitation, now or in the foreseeable future. The following calculations and configuration description for the spherical capsules demonstrate the feasibility of the invention with respect to the spheres shown in FIG. 1 which are described below. The example is offered as illustrative, but not limiting. As an example of a disposal site, the central Greenland icecap was chosen. Recent drillings to the bottom of the ice have shown that it has remained stable for 100,000 years. Borehole temperature varies from xe2x88x9235xc2x0 C. on top to about xe2x88x9210xc2x0 C. at the bottom. For the fission product disposal, a typical power reactor, namely a 1000 MWe reactor, was chosen as the reference case. A 1000 MWe reactor operating at 33% efficiency will generate 3.12 kg of fission products per day. Typically about 100 metric tons (i.e. Megagrams, Mg, or tonnes) of fuel will be irradiated in a power reactor to a burnup of 2600 TJ per ton of reactor fuel (30,000 Megawatt days per tonne). One third of the fuel is generally replaced annually, giving a residence time of three years. Annual reactor operation for 330 days will thus generate 330xc3x973.12=1029.6 kg of fission products, or just about one tonne. From yield tables for the fission of U235 (Benedict, M. and Pigford, T., et al., Nuclear Chemical Engineering, 2nd ed., McGraw Hill, New York, 1981) and density data (Emsley, J., The Elements, Oxford University Press, Oxford, 1989) it can be shown that fission products from one tonne of U235 fissioned will, when Xenon and Krypton are discounted, produce close to 834 kilograms of elemental fission products that have a mean density of 4200 kg/m3. If the fission products apart from Xenon and Krypton are in oxide form (assuming the highest oxidation states), one tonne of U235 will generate about one tonne of fission product oxides. These will have a mean density of about 4260 kg/m3 and occupy a volume of 0.237 m3. The results of such a calculation are shown in Table 1. It is given that the actinides should be separated from the fission products to the maximum feasible extent because of their long life. They can be reprocessed to be used mostly as fuel. The remaining fission products will have to be isolated from the environment for 800-1000 years, after which they are no more hazardous than the uranium ore from which they originated, or the uranium ore that must also exist naturally under such large icecaps as the Greenland icecap. FIG. 1 shows a typical disposal capsule (spherical in this example) configuration and its dimensions. The constraints on the design of a capsule 10, which consists of a core matrix 11 in which the fission products 12 are embedded and a radiation shield 13, to transport them through the ice are: (1) the temperature at the center 14, which limits both the amount and the concentration of the fission products 12 which can be encapsulated in one unit 10; (2) the radiation outside the capsule 10, which must not exceed safety limits while being handled and transported prior to burial in the ice; and (3) the outside surface 16 temperature of the capsule which must be sufficient to melt the ice while it is reaching bottom, yet not sufficiently high to seriously enhance corrosion of the capsule. The constraint that the fission products (in oxide form in this example) 12 at the center of the container shall remain solid and preferably none to decompose, puts very strict limitations on how high the temperature can be allowed to rise at the center 14. Ultimately this depends on the rate of heat generation per unit volume in the core 11 that the fission products 12 are embedded in, the volume they occupy, their age, the material they may be mixed with, and the rate of heat removal. The heat removal rate, in turn, depends upon the size of the container 10, the thermal conductivity of the core 11 and shield 13, as well as the thermal conductivity of the surrounding environment (i.e., whether it is air, water, or ice). The second criterion listed above also depends upon the core volume containing the fission products 12, the materials they are mixed with, and the thickness of the shield 13, as well as its material. The same factors apply to the third criterion. The restrictions that these criteria impose may overlap, yet all three have to be met. The best solution is to start by storing the spent fuel for a period to let the short lived fission products decay. All things considered, a period of ten years seems desirable. Then the fuel should be reprocessed and the fission products separated from the actinides. The latter should be recycled and fissioned or transmuted into shorter lived isotopes. The extended storage and the removal of the actinides greatly relaxes both the shielding and thermal constraints. None the less, it was found that the thermal restrictions still necessitated dividing the ton of fission product oxides into smaller portions to be individually encapsulated. The size of the portions depends on the core temperature restrictions which, in turn, depend on whether the fission products (or their oxides in this example) are mixed with another material or not and, if so, which material. A conservative approach would be to embed the calcined fission products 12 in a metal matrix , similar to what is done in the PAMELA process (Benedict, M., Pigford, T. H., Levi H. W., Nuclear Chemical Engineering, McGraw Hill Book Company, New York, 1981), which is incorporated herein by reference. This entails a lead content of 33% by volume. A lead alloy, such as a tin lead alloy, or some other metal may also be used. However, lead""s or the lead alloy""s low melting point and poor thermal conductivity limit the total energy released by radiation within each sphere to much lesser values than a metal with a higher melting point, or thermal conductivity such as copper. Copper, on the other hand, may be incompatible with some of the more volatile fission products or their unstable oxides when molten copper is applied to form the embedding matrix. This might require separate handling for the volatile fission products such as iodine. However, the embedding matrix may also be deposited by electrochemical means. Copper also has a lower linear absorption coefficient for gamma rays than does lead. During the storage period many fission products with short half lives become insignificant as radiation sources. The more pertinent ones from a shielding point of view are listed in Table 2. Because of the low penetrating power of beta radiation, only gamma shielding needs consideration. The shield can be made of a variety of corrosion resistant materials that have good radiation shielding and thermal characteristics, certain grades of stainless steel being among them. An accurate shield 13 design, of for example stainless steel (other known corrosion resistant materials can also be used), requires a multigroup-multiregion calculation, but a less precise analytical approach will be used here which none the less is sufficiently accurate for illustrative design purposes. The basis for the capsule design in this example will be 100 kg of fission products embedded in oxide form in a lead matrix where the fission product oxide content is 67% by volume. The volume occupied by the oxides and the lead is referred to as the core volume. Averaging of density data from Table 1 and the density of lead will give an average density of 6600 kg/m3 for the core volume. For 100 kg of fission products this volume will be 0.036 m3 which corresponds to a radius of just about 0.2 m. From Table 2 it is seen that the average gamma energy is 0.72 Mev. This gives the core a mass absorption coefficient of 0.085 cm2/g, which at the given density corresponds to a linear absorption coefficient of 0.563 cmxe2x88x921. The reciprocal, namely the relaxation length, xcexc, will be 1.77 cm or 0.0177 m for the core volume. For the stainless steel encapsulating the core, with a density of 7800 kg/m3 and a corresponding mass absorption coefficient of 0.073 cm2/g, the value of the relaxation length turns out to be almost the same, or 0.0176 m. From Table 2 it is seen that the gamma flux for the ton or so of fission product oxides that stem from 33 tons of spent fuel that has been stored for ten years is 1.042xc3x971017 photons/s. When the fission product oxides are subdivided into the 100 kg lots as are contained in the core volume, it is seen that the gamma radiation from the core is 1.042xc3x971017xc3x970.1=1.042xc3x971016 photons/s. Given the core volume of 0.036 m3, this will give a core volume unit strength, S(xcexd,xcex3), of: S(xcexd,xcex3)=1.042xc3x971016/0.036xc3x972.894xc3x971017 photons/s m3xe2x80x83xe2x80x83(1) The corresponding surface flux, S(a,xcex3), from the core will be: S(a,xcex3)=xcexcS(xcexd,xcex3)=0.0177xc3x972.894xc3x971017=5.123xc3x971015 photons/s m2xe2x80x83xe2x80x83(2) If the criterion is set that the gamma energy flux outside the shield should not exceed five nanowatts/m2, this would correspond to a flux of about 50,000 photons/s m2 as the average gamma photon energy is 0.7 Mev. For a reasonable approximation for the necessary shield thickness for a spherical surface source one can use the expression (See Glasstone, S. and Sesonsky, A., Nuclear Reactor Engineering, D. Van Nostrand and Co., New York, 1963, Chapter 10). xcfx86(z)=B(z)(S(a,xcex3)(r/r(i))E1(z/xcex)/2xe2x80x83xe2x80x83(3) where: xcfx86(z)=gamma flux outside the shield=50,000 photons/s m2. B(z)=Buildup factor here taken as=1. r=distance from center of the sphere to the detector, m. r(i)=radius of spherical source=0.2 m. z=distance from surface of the source to the detector, m. xcex=relaxation length of gamma photons in shield=0.0177 m. E1(z/xcex)=the exponential integral of the first order of z/xcex. For large values, such as here, the approximation E1(x)=exp(xe2x88x92x)/x may be used. If the detector is at the outer surface of the shield 16, z=r-r(i). With the above established numbers the solution to eq""n (3) then gives a value of r=0.6 m., i.e. the shield thickness will be 0.4 m. Whereas the beta activity could be ignored for the purposes of shielding calculations, it is a major contributor to the generation of thermal power in the core 11. From Table 2 it is seen that the beta activity of the major fission products after ten years of storage contributes 1470 W. per tonne of spent fuel, or 3.3xc3x971470=4851 W. for the 3.3 tonnes that correspond to the 100 kg of fission product oxides in the core volume. Corresponding gamma energy is 365xc3x973.3=1205 W. This gives a total heat rate of 4851+1205=6056 W. for the core volume. As essentially all the beta radiation is absorbed within the core volume because of its low penetrating power, all the associated heating may be considered arising there. The gamma radiation penetrates into the shield, as was borne out by the shielding calculations. However, the bulk (i.e. 95%) of the gamma heat energy is deposited in the first three relaxation lengths of shield enclosing the core (and much of that in the first cm or so). For the present case the gamma heating in the shield may be ignored for heat transmission purposes and all the gamma heat also considered to stem from the core volume. (The incurred error should not exceed 3%). Using the previously calculated figures for heat generation rate and core volume, the specific rate of heat generation in the core, S(v,q), is found to be 6056/0.036=168,222 W/m3. The Poisson equation describes the relationship between heat generation, thermal conductivity, k, and the temperature profile for the steady state case: ∇2T+S(v, q)/k=0xe2x80x83xe2x80x83(4) In spherical coordinates, with the boundary conditions that T(c) is the temperature at the center and T(i) its value at the surface of the fission product sphere of radius r(i), the solution is: xe2x80x83T(c)xe2x88x92T(i)=S(v,q)r(i)2/(6k)xe2x80x83xe2x80x83(5) The value of k for the core is taken as 10 W/m deg. C (Benedict, M. and Pigford, T., et al., Nuclear Chemical Engineering, 2nd ed., McGraw Hill, New York, 1981 p. 584). Then using the values calculated above, i.e. S(v,q)=168,222 W/m3 and r(i)=0.2 m: T(c)xe2x88x92T(i)=168,222xc3x970.22/(6xc3x9710)=112 deg. Cxe2x80x83xe2x80x83(6) For the shield, when S(v,q) becomes zero, the Poisson equation simplifies to the Laplace equation: ∇2T=0xe2x80x83xe2x80x83(7) the solution of which is: T(i)xe2x88x92T(o)=(q/4xcfx80k)(1/r(i)xe2x88x921/r(o))xe2x80x83xe2x80x83(8) where r(o) signifies the outer radius of the shield and T(o) the corresponding temperature and q the rate of heat transfer through the shield. The value of k, the heat transfer coefficient, for the stainless steel is taken as 18 W/m deg C. With the appropriate numbers introduced into the equation, the temperature drop across the shield is found to be: T(i)xe2x88x92T(o)=(6056/4xcfx80xc3x9718)(1/0.2xe2x88x921/0.6)=89 deg Cxe2x80x83xe2x80x83(9) The temperature profile for both core and shield is shown in FIG. 2. The temperature drop from the center of the core to the outer surface of the shield is 89+112=201 deg C. The ratio of the thermal conductivities of ice (2.24 W/m deg C) and stainless steel are such that even if the surface ice is at xe2x88x9235xc2x0 C., it cannot conduct the heat away fast enough to prevent melting at the rate of heat generation under consideration. The temperature gradient in the water boundary layer adjacent to the surface of the sphere will be steeper than in the shield and raise the sphere surface temperature somewhat above the freezing point. Once an icemelt is formed, convection will also play a part in cooling the sphere but the exact calculation is quite complicated and will not be undertaken here. In the central region of the Greenland Icecap (or Antarctica) the sphere will have to melt a volume of ice that equals its own diameter and is 3000 m in height. Given the density of ice at 900 kg/m3 and the radius of the sphere of 0.6 m, the mass of ice, m, that the sphere will have to melt will be: m=900xc3x97xcfx80xc3x970.62xc3x973000=3.053xc3x97106 kgxe2x80x83xe2x80x83(10) Besides melting the ice the sphere has to heat the ice from the ambient temperature to the melting point. The former varies from xe2x88x9235xc2x0 C. at the surface to xe2x88x9210xc2x0 C. or so at the bottom, as mentioned earlier, and the melting point somewhat because of pressure increase with depth. Nonetheless, for a conservative estimate the temperature will be considered constant at xe2x88x9235xc2x0 C. and the melting point also constant. The heat of fusion of water is 334 kJ/kg and the specific heat of ice just about 2 kJ/kg deg C. The total heat required to heat the ice from xe2x88x9235xc2x0 C. and melt the sphere to the bottom, Q, will thus be: Q=3.053xc3x97106xc3x97(2xc3x9735+334)=1.233xc3x97109 kJxe2x80x83xe2x80x83(11) or 1.233xc3x971012 J. After ten years of storage the dominant fission products are Sr 90 and Cs 137 in secular equilibrium with their daughter nuclides, Y 90 and Ba 137m. Sr 90 and Cs 137 decay with very similar half lifes, namely nearly 29 years for both. For these reasons the ten year old mixture of fission products under consideration here may be considered to have a half life of 29 years for heat generation purposes. (This can change with time as the strontium and cesium isotopes decay further over a period of centuries, which leaves some longer lived nuclides dominant). Hence the effective decay constant for the fission product mixture, xcexd, will have the value: xcexd=1n(2)/t1/2=0.693/30=0.0231 per yearxe2x80x83xe2x80x83(12) To be commensurate with watts xcexd should be expressed in reciprocal seconds, that is xcexd=0.0231/3.156xc3x97107=7.320xc3x971010 per second where the denominator is the number of seconds in a year. The rate of heat generation, q, as a function of time will then be given by q(t)=q10exp(xe2x88x92xcexdt). The heat output must be integrated over the time that it takes the radwaste sphere to reach the bottom of the glacier, t(b). This has to equal the total heat requirements, Q, calculated above. Hence: Q = ∫ 0 t ⁡ ( b ) ⁢ q 10 ⁢ exp ⁡ ( - λ d ⁢ t ) ( 13 ) where, as before: xcexd=effective decay constant at ten years=7.320xc3x971010 sxe2x88x921 q10=decay heat rate of ten year old fission products=6056 w. Q=total heat requirements for reaching bottom=1.233xc3x971012J. Solving for t(b) yields the expression: t (b)=(1/xcexd)ln(lxe2x88x92xcexdQ/q10)xe2x80x83xe2x80x83(14) or, when the numbers are substituted: t(b)=(1/7.32xc3x971010)ln(1xe2x88x927.32xc3x9710xe2x88x9210xc3x971.233xc3x971012/6056)=2.205xc3x97108sxe2x80x83xe2x80x83(15) which is equivalent to 2.205xc3x97108/3.156xc3x97107=7.0 years. This example and its calculations demonstrate the feasibility of storing nuclear wastes in a safe manner in deep permanent icefields. It should be recalled that the assumption was made that spent fuel reprocessing would be undertaken and the long lived actinides recycled, or disposed of by other means. That is not to say that ice burial might not be considered for them as well, whether separately or unseparated from the fission products. Although separation and recycling of the actinides is preferable, an assured storage of the actinides for 100,000 years would diminish the activity of the plutonium by a factor of 16. Although the Greenland glacier was taken as an example in this study, it should be borne in mind that from a disposal point of view Antarctica would be even better because of its remoteness and greater depth of the ice. The disposal of fission products in deep permanent icefields as is described here is a technically feasible solution to the worrisome problem of accumulating nuclear waste in many countries. Apart from providing permanent storage (in any case long enough for the fission product activity to cease being a hazard and a time period of the order of 100,000 years), the fission products are adequately shielded in remote unpopulated areas. Furthermore, they are easily placed in storage but become inaccessible a few years if not months after they are placed on the ice. This holds the promise of making it a much more cost effective solution than deep geological burial, or shooting the nuclear wastes into space, as has been proposed. It therefore can be seen that the invention accomplishes all of its stated objectives.
050531913	claims	1. A hold-down spring for a nuclear fuel assembly, comprising: an elongated metal bar having a substantially straight long leg portion with one end adapted to be mounted to a fuel assembly, an arcuate transition portion at the other end of the long leg, a straight short leg portion extending from the transition portion at an acute included angle with the long leg portion, and load transfer means projecting from the straight leg intermediate the transition portion and the long leg first end. 2. In a nuclear fuel assembly having an upper end fitting and at least one spring pack projecting above the upper end fitting for interaction with a core upper support plate bearing on the assembly through said spring packs, the improvement wherein said spring pack comprises: a primary spring member including a long straight leg portion having one end attached to the frame of the upper end fitting an arcuate transition portion at the other end of the long leg, and a straight short leg portion extending from the transition portion at an acute included angle with the long leg, the primary spring member being oriented on the end fitting so that the transition portion is at the vertical highest elevation, whereby movement of the end fitting and upper core plate relatively toward each other primarily loads the transition portion and deflects the long leg portion about the attachment to the end fitting frame; at least one secondary spring having first and second end, the first end attached to the upper end fitting adjacent the first end of the primary spring long leg, and a second end terminating adjacent the transition portion, and means at the second end of the secondary spring for interacting with the transition portion to resist downward movement of the transition portion as the primary spring member deflects in a cantilever fashion; load transfer means formed on the long leg portion intermediate the transition portion and the long leg first end, said transfer means having an elevation vertically lower than that of the primary loading point and vertically higher than the upper end fitting frame; whereby at a known deflection of the primary spring member resulting from the movement of the core plate and end fitting toward each other, the core plate contacts the load transfer means and thereby reduces the effective length and increases the stiffness of the primary spring. 3. In a nuclear reactor having a core defined by a plurality of side by side, vertically extending, elongated nuclear fuel assemblies each having an upper end fitting, an upper core plate oriented horizontally in closely spaced relation to the upper end fittings, and a plurality of spring packs attached to the upper end fittings and cantilevered toward the core plate so as to resiliently urge the fuel assemblies against the lower core plate, said cantilevered spring having a loading point at a preset distance from the attachment point, wherein the improvement comprises the cantilevered spring having a projection toward the upper core plate which contacts the core plate when the core plate deflects the spring a predetermined amount, thereby effectively shortening and stiffening the spring against further movement of the core plate relatively toward the upper end fitting of the spring a second loading.
	description	This application is a continuation-in-part of U.S. patent application Ser. No. 15/152,479 filed May 11, 2016, which: is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/087,096 filed Apr. 14, 2011, which claims benefit of U.S. provisional patent application No. 61/324,776 filed Apr. 16, 2010; is a continuation-in-part of U.S. patent application Ser. No. 14/952,817 filed Nov. 25, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 14/293,861 filed Jun. 2, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 12/985,039 filed Jan. 5, 2011, which claims the benefit of U.S. provisional patent application No. 61/324,776, filed Apr. 16, 2010; and is a continuation-in-part of U.S. patent application Ser. No. 14/860,577 filed Sep. 21, 2015, which is a continuation of U.S. patent application Ser. No. 14/223,289 filed Mar. 24, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 12/985,039 filed Jan. 5, 2011, which claims the benefit of U.S. provisional patent application No. 61/324,776, filed Apr. 16, 2010, all of which are incorporated herein in their entirety by this reference thereto. Field of the Invention This invention relates generally to treatment of solid cancers. More particularly, the invention relates to a synchrotron energy control system of a multi-axis and/or multi-field charged particle cancer therapy method and apparatus. Discussion of the Prior Art Cancer Treatment Proton therapy works by aiming energetic ionizing particles, such as protons accelerated with a particle accelerator, onto a target tumor. These particles damage the DNA of cells, ultimately causing their death. Cancerous cells, because of their high rate of division and their reduced ability to repair damaged DNA, are particularly vulnerable to attack on their DNA. Synchrotron Patents related to the current invention are summarized here. Proton Beam Therapy System F. Cole, et. al. of Loma Linda University Medical Center “Multi-Station Proton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describe a proton beam therapy system for selectively generating and transporting proton beams from a single proton source and accelerator to a selected treatment room of a plurality of patient treatment rooms. Imaging P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,274,018 (Sep. 25, 2007) and P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,045,781 (May 16, 2006) describe a charged particle beam apparatus configured for serial and/or parallel imaging of an object. K. Hiramoto, et. al. “Ion Beam Therapy System and its Couch Positioning System”, U.S. Pat. No. 7,193,227 (Mar. 20, 2007) describe an ion beam therapy system having an X-ray imaging system moving in conjunction with a rotating gantry. C. Maurer, et. al. “Apparatus and Method for Registration of Images to Physical Space Using a Weighted Combination of Points and Surfaces”, U.S. Pat. No. 6,560,354 (May 6, 2003) described a process of X-ray computed tomography registered to physical measurements taken on the patient's body, where different body parts are given different weights. Weights are used in an iterative registration process to determine a rigid body transformation process, where the transformation function is used to assist surgical or stereotactic procedures. M. Blair, et. al. “Proton Beam Digital Imaging System”, U.S. Pat. No. 5,825,845 (Oct. 20, 1998) describe a proton beam digital imaging system having an X-ray source that is movable into a treatment beam line that can produce an X-ray beam through a region of the body. By comparison of the relative positions of the center of the beam in the patient orientation image and the isocentre in the master prescription image with respect to selected monuments, the amount and direction of movement of the patient to make the best beam center correspond to the target isocentre is determined. S. Nishihara, et. al. “Therapeutic Apparatus”, U.S. Pat. No. 5,039,867 (Aug. 13, 1991) describe a method and apparatus for positioning a therapeutic beam in which a first distance is determined on the basis of a first image, a second distance is determined on the basis of a second image, and the patient is moved to a therapy beam irradiation position on the basis of the first and second distances. Problem There exists in the art of charged particle irradiation therapy a need to accurately and precisely deliver an effective and uniform radiation dose to all positions of a tumor. There further exists a need for accurately, precisely, and timely locating and targeting a tumor in a patient. There still further exists a need in the art to control the charged particle cancer therapy system in terms of patient translation position, patient rotation position, specified energy, specified intensity, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. There yet still further exists a need for an integrated control system to control and/or to directly control subsystems of a cancer treatment process for enhanced efficacy and safety. Preferably, the system would operate in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus. The invention comprises a synchrotron energy control apparatus and method of use thereof. Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that are performed concurrently or in different order are illustrated in the figures to help improve understanding of embodiments of the present invention. The invention relates generally to control of energy of a beam of charged particles extracted from a synchrotron. Herein, for clarity of presentation and without limitation, extracted beam energy control is described in combination with a charged particle cancer therapy system. However, more generally, the method and apparatus for extracting a charged particle beam from a synchrotron is optionally used in conjunction with any apparatus and/or technique coupled to a synchrotron. In one embodiment, an energy of a charged particle beam is calculated from a known pathlength of beam circulation in a synchrotron, a time period of beam circulation in the synchrotron, and a knowledge of an amount of beam slowing resultant from an extraction material. In another embodiment, the charged particle energy control apparatus is used in combination with a charged particle cancer therapy system. The charged particle cancer therapy system uses the same injector, accelerator, and guided delivery system in delivering charged particles to the cancerous tumor. For example, the tomography apparatus and cancer therapy system use a common raster beam method and apparatus for treatment of solid cancers. More particularly, the invention comprises a multi-axis and/or multi-field raster beam charged particle accelerator used in tomography and cancer therapy. Optionally, the system independently controls patient translation position, patient rotation position, two-dimensional beam trajectory, delivered radiation beam energy, delivered radiation beam intensity, beam velocity, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. The system operates in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus to deliver an effective and uniform dose of radiation to a tumor while distributing radiation striking healthy tissue. In various embodiments, the charged particle tomography system optionally includes any of: charged particle imaging at the same time or within seconds of delivery of charged particles for cancer therapy; ability to image the tumor by rotation of the patient; ability to collect tens or hundreds of rotationally independent images to construct the three-dimensional image of the tumor and the patient; adaptive charged particle therapy; and/or imaging of the patient in an upright position. Herein, common elements of the tomography system are first described using a cancer therapy system. Any of the cancer therapy elements are optionally used in the later described charged particle tomography system. Used in combination with the invention, novel design features of a charged particle beam cancer therapy system are described. Particularly, a negative ion beam source with novel features in the negative ion source, ion source vacuum system, ion beam focusing lens, and tandem accelerator is described. Additionally, the synchrotron includes: turning magnets, edge focusing magnets, magnetic field concentration magnets, winding and correction coils, flat magnetic field incident surfaces, and extraction elements, which minimize the overall size of the synchrotron, provide a tightly controlled proton beam, directly reduce the size of required magnetic fields, directly reduce required operating power, and allow continual acceleration of protons in a synchrotron even during a process of extracting protons from the synchrotron. The ion beam source system and synchrotron are preferably computer integrated with a patient imaging system and a patient interface including respiration monitoring sensors and patient positioning elements. Further, the system is integrated with intensity control of a charged particle beam, acceleration, extraction, and/or targeting method and apparatus. More particularly, intensity, energy, and timing control of a charged particle stream of a synchrotron is coordinated with patient positioning and tumor treatment. The synchrotron control elements allow tight control of the charged particle beam, which compliments the tight control of patient positioning to yield efficient treatment of a solid tumor with reduced tissue damage to surrounding healthy tissue. In addition, the system reduces the overall size of the synchrotron, provides a tightly controlled proton beam, directly reduces the size of required magnetic fields, directly reduces required operating power, and allows continual acceleration of protons in a synchrotron even during a process of extracting protons from the synchrotron. All of these systems are preferably used in conjunction with an X-ray system capable of collecting X-rays of a patient: (1) in a positioning, immobilization, and automated repositioning system for proton treatment; (2) at a specified moment of the patient's respiration cycle; and (3) using coordinated translation and rotation of the patient. Combined, the systems provide for efficient, accurate, and precise noninvasive tumor treatment with minimal damage to surrounding healthy tissue. In various embodiments, the charged particle cancer therapy system incorporates any of: an injection system having a central magnetic member and a magnetic field separating high and low temperature plasma regions; a dual vacuum system creating a first partial pressure region on a plasma generation system side of a foil in a tandem accelerator and a second lower partial pressure region on the synchrotron side of the foil; a negative ion beam focusing system having a conductive mesh axially crossing the negative ion beam; a synchrotron having four straight sections and four turning sections; a synchrotron having no hexapole magnets; four bending magnets in each turning section of the synchrotron; a winding coil wrapping multiple bending magnets; a plurality of bending magnets that are beveled and charged particle focusing in each turning section; a magnetic field concentrating geometry approaching the gap through which the charged particles travel; correction coils for rapid magnetic field changes; magnetic field feedback sensors providing signal to the correction coils; integrated RF-amplifier microcircuits providing currents through loops about accelerating coils; a low density foil for charged particle extraction; a feedback sensor for measuring particle extraction allowing intensity control; a synchrotron independently controlling charged particle energy and intensity; a layer, after synchrotron extraction and before the tumor, for imaging the particle beam x-, y-axis position; a rotatable platform for turning the subject allowing multi-field imaging and/or multi-field proton therapy; a radiation plan dispersing ingress Bragg profile energy 360 degrees about the tumor; a long lifetime X-ray source; an X-ray source proximate the charged particle beam path; a multi-field X-ray system; positioning, immobilizing, and repositioning systems; respiratory sensors; simultaneous and independent control of: x-axis beam control; y-axis beam control; irradiation beam energy; irradiation beam intensity; patient translation; and/or patient rotation; and a system timing charged particle therapy to one or more of: patient translation; patient rotation; and patient respiration. In another embodiment, safety systems for a charged particle system are implemented. For example, the safety system includes any of: multiple X-ray images from multiple directions, a three-dimensional X-ray image, a proton beam approximating a path of an X-ray beam, tight control of a proton beam cross-sectional area with magnets, ability to control proton beam energy, ability to control proton beam energy, a set of patient movement constrains, a patient controlled charged particle interrupt system, distribution of radiation around a tumor, and timed irradiation in terms of respiration. In yet another embodiment, the tumor is imaged from multiple directions in phase with patient respiration. For example, a plurality of two-dimensional pictures are collected that are all in the about the same phase of respiration. The two-dimensional pictures are combined to produce a three-dimensional picture of the tumor relative to the patient. One or more safety features are optionally used in the charged particle cancer therapy system independently and/or in combination with the three-dimensional imaging system, as described infra. In still yet another embodiment, the system independently controls patient translation position, patient rotation position, two-dimensional beam trajectory, delivered radiation beam energy, delivered radiation beam intensity, timing of charged particle delivery, beam velocity, and/or distribution of radiation striking healthy tissue. The system operates in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus to deliver an effective and uniform dose of radiation to a tumor while distributing radiation striking healthy tissue. Charged Particle Beam Therapy Throughout this document, a charged particle beam therapy system, such as a proton beam, hydrogen ion beam, or carbon ion beam, is described. Herein, the charged particle beam therapy system is described using a proton beam. However, the aspects taught and described in terms of a proton beam are not intended to be limiting to that of a proton beam and are illustrative of a charged particle beam system. Any of the techniques described herein are equally applicable to any charged particle beam system. Referring now to FIG. 1, a charged particle beam system 100 is illustrated. The charged particle beam preferably comprises a number of subsystems including any of: a main controller 110; an injection system 120; a synchrotron 130 that typically includes: (1) an accelerator system 132 and (2) an extraction system 134; a scanning/targeting/delivery system 140; a patient interface module 150; a display system 160; and/or an imaging system 170. An exemplary method of use of the charged particle beam system 100 is provided. The main controller 110 controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller 110 obtains an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 then optionally controls the injection system 120 to inject a proton into a synchrotron 130. The synchrotron typically contains at least an accelerator system 132 and an extraction system 134. The main controller 110 preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The controller 110 also preferably controls targeting of the proton beam through the scanning/targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150, such as translational and rotational position of the patient, are preferably controlled by the main controller 110. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient. Herein, the main controller 110 refers to a single system controlling the charged particle beam system 100, to a single controller controlling a plurality of subsystems controlling the charged particle beam system 100, or to a plurality of individual controllers controlling one or more sub-systems of the charged particle beam system 100. Referring now to FIG. 2, an illustrative exemplary embodiment of one version of the charged particle beam system 100 is provided. The number, position, and described type of components is illustrative and non-limiting in nature. In the illustrated embodiment, the injection system 120 or ion source or charged particle beam source generates protons. The protons are delivered into a vacuum tube that runs into, through, and out of the synchrotron. The generated protons are delivered along an initial path 262. Focusing magnets 230, such as quadrupole magnets or injection quadrupole magnets, are used to focus the proton beam path. A quadrupole magnet is a focusing magnet. An injector bending magnet 232 bends the proton beam toward the plane of the synchrotron 130. The focused protons having an initial energy are introduced into an injector magnet 240, which is preferably an injection Lamberson magnet. Typically, the initial beam path 262 is along an axis off of, such as above, a circulating plane of the synchrotron 130. The injector bending magnet 232 and injector magnet 240 combine to move the protons into the synchrotron 130. Main bending magnets, dipole magnets, turning magnets, or circulating magnets 250 are used to turn the protons along a circulating beam path 264. A dipole magnet is a bending magnet. The main bending magnets 250 bend the initial beam path 262 into a circulating beam path 264. In this example, the main bending magnets 250 or circulating magnets are represented as four sets of four magnets to maintain the circulating beam path 264 into a stable circulating beam path. However, any number of magnets or sets of magnets are optionally used to move the protons around a single orbit in the circulation process. The protons pass through an accelerator 270. The accelerator accelerates the protons in the circulating beam path 264. As the protons are accelerated, the fields applied by the magnets are increased. Particularly, the speed of the protons achieved by the accelerator 270 are synchronized with magnetic fields of the main bending magnets 250 or circulating magnets to maintain stable circulation of the protons about a central point or region 280 of the synchrotron. At separate points in time the accelerator 270/main bending magnet 250 combination is used to accelerate and/or decelerate the circulating protons while maintaining the protons in the circulating path or orbit. An extraction element of the inflector/deflector system 290 is used in combination with a Lamberson extraction magnet 292 to remove protons from their circulating beam path 264 within the synchrotron 130. One example of a deflector component is a Lamberson magnet. Typically the deflector moves the protons from the circulating plane to an axis off of the circulating plane, such as above the circulating plane. Extracted protons are preferably directed and/or focused using an extraction bending magnet 237 and extraction focusing magnets 235, such as quadrupole magnets along a transport path 268 into the scanning/targeting/delivery system 140. Two components of a scanning system 140 or targeting system typically include a first axis control 142, such as a vertical control, and a second axis control 144, such as a horizontal control. In one embodiment, the first axis control 142 allows for about 100 mm of vertical or y-axis scanning of the proton beam 268 and the second axis control 144 allows for about 700 mm of horizontal or x-axis scanning of the proton beam 268. A nozzle system 146 is used for imaging the proton beam and/or as a vacuum barrier between the low pressure beam path of the synchrotron and the atmosphere. Protons are delivered with control to the patient interface module 150 and to a tumor of a patient. All of the above listed elements are optional and may be used in various permutations and combinations. Each of the above listed elements are further described, infra. Ion Beam Generation System An ion beam generation system generates a negative ion beam, such as a hydrogen anion or H− beam; preferably focuses the negative ion beam; converts the negative ion beam to a positive ion beam, such as a proton or H+ beam; and injects the positive ion beam 262 into the synchrotron 130. Portions of the ion beam path are preferably under partial vacuum. Each of these systems are further described, infra. Referring now to FIG. 3, an exemplary ion beam generation system 300 is illustrated. As illustrated, the ion beam generation system 300 has four major subsections: a negative ion source 310, a first partial vacuum system 330, an optional ion beam focusing system 350, and a tandem accelerator 390. Still referring to FIG. 3, the negative ion source 310 preferably includes an inlet port 312 for injection of hydrogen gas into a high temperature plasma chamber 314. In one embodiment, the plasma chamber includes a magnetic material 316, which provides a magnetic field 317 between the high temperature plasma chamber 314 and a low temperature plasma region on the opposite side of the magnetic field barrier. An extraction pulse is applied to a negative ion extraction electrode 318 to pull the negative ion beam into a negative ion beam path 319, which proceeds through the first partial vacuum system 330, through the ion beam focusing system 350, and into the tandem accelerator 390. Still referring to FIG. 3, the first partial vacuum system 330 is an enclosed system running from the hydrogen gas inlet port 312 to a foil 395 in the tandem accelerator 390. The foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the first partial vacuum system side of the foil 395 and a lower pressure, such as about 10−7 torr, to be maintained on the synchrotron side of the foil. By only pumping first partial vacuum system 330 and by only semi-continuously operating the ion beam source vacuum based on sensor readings, the lifetime of the semi-continuously operating pump is extended. The sensor readings are further described, infra. Still referring to FIG. 3, the first partial vacuum system 330 preferably includes: a first pump 332, such as a continuously operating pump and/or a turbo molecular pump; a large holding volume 334; and a semi-continuously operating pump 336. Preferably, a pump controller 340 receives a signal from a pressure sensor 342 monitoring pressure in the large holding volume 334. Upon a signal representative of a sufficient pressure in the large holding volume 334, the pump controller 340 instructs an actuator 345 to open a valve 346 between the large holding volume and the semi-continuously operating pump 336 and instructs the semi-continuously operating pump to turn on and pump to atmosphere residual gases out of the vacuum line 320 about the charged particle stream. In this fashion, the lifetime of the semi-continuously operating pump is extended by only operating semi-continuously and as needed. In one example, the semi-continuously operating pump 336 operates for a few minutes every few hours, such as 5 minutes every 4 hours, thereby extending a pump with a lifetime of about 2,000 hours to about 96,000 hours. Further, by isolating the inlet gas from the synchrotron vacuum system, the synchrotron vacuum pumps, such as turbo molecular pumps can operate over a longer lifetime as the synchrotron vacuum pumps have fewer gas molecules to deal with. For example, the inlet gas is primarily hydrogen gas but may contain impurities, such as nitrogen and carbon dioxide. By isolating the inlet gases in the negative ion source system 310, first partial vacuum system 330, ion beam focusing system 350, and negative ion beam side of the tandem accelerator 390, the synchrotron vacuum pumps can operate at lower pressures with longer lifetimes, which increases operating efficiency of the synchrotron 130. Still referring to FIG. 3, the optimal ion beam focusing system 350 preferably includes two or more electrodes where one electrode of each electrode pair partially obstructs the ion beam path with conductive paths 372, such as a conductive mesh. In the illustrated example, two ion beam focusing system sections are illustrated, a two electrode ion beam focusing section 360 and a three electrode ion beam focusing section 370. For a given electrode pair, electric field lines, running between the conductive mesh of a first electrode and a second electrode, provide inward forces focusing the negative ion beam. Multiple such electrode pairs provide multiple negative ion beam focusing regions. Preferably the two electrode ion focusing section 360 and the three electrode ion focusing section 370 are placed after the negative ion source and before the tandem accelerator and/or cover a space of about 0.5, 1, or 2 meters along the ion beam path 319. Ion beam focusing systems are further described, infra. Still referring to FIG. 3, the tandem accelerator 390 preferably includes a foil 395, such as a carbon foil. The negative ions in the negative ion beam path 319 are converted to positive ions, such as protons, and the initial ion beam path 262 results. The foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the side of the foil 395 having the negative ion beam path 319 and a lower pressure, such as about 10−7 torr, to be maintained on the side of the foil 390 having the proton ion beam path 262. Having the foil 395 physically separating the vacuum chamber 320 into two pressure regions allows for a system having fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron 130 as the inlet hydrogen and its residuals are extracted in a separate contained and isolated space by the first partial vacuum system 330. Negative Ion Source An example of the negative ion source 310 is further described herein. Referring now to FIG. 4, a cross-section of an exemplary negative ion source system 400 is provided. The negative ion beam 319 is created in multiple stages. During a first stage, hydrogen gas is injected into a chamber. During a second stage, a negative ion is created by application of a first high voltage pulse, which creates a plasma about the hydrogen gas to create negative ions. During a third stage, a magnetic field filter is applied to components of the plasma. During a fourth stage, the negative ions are extracted from a low temperature plasma region, on the opposite side of the magnetic field barrier, by application of a second high voltage pulse. Each of the four stages are further described, infra. While the chamber is illustrated as a cross-section of a cylinder, the cylinder is exemplary only and any geometry applies to the magnetic loop containment walls, described infra. In the first stage, hydrogen gas 440 is injected through the inlet port 312 into a high temperature plasma region 490. The injection port 312 is open for a short period of time, such as less than about 1, 5, or 10 microseconds to minimize vacuum pump requirements to maintain vacuum chamber 320 requirements. The high temperature plasma region is maintained at reduced pressure by the partial vacuum system 330. The injection of the hydrogen gas is optionally controlled by the main controller 110, which is responsive to imaging system 170 information and patient interface module 150 information, such as patient positioning and period in a respiration cycle. In the second stage, a high temperature plasma region is created by applying a first high voltage pulse across a first electrode 422 and a second electrode 424. For example a 5 kV pulse is applied for about 20 microseconds with 5 kV at the second electrode 424 and about 0 kV applied at the first electrode 422. Hydrogen in the chamber is broken, in the high temperature plasma region 490, into component parts, such as any of: atomic hydrogen, H0, a proton, H+, an electron, e−, and a hydrogen anion, H−. In the third stage, the high temperature plasma region 490 is at least partially separated from a low temperature plasma region 492 by the magnetic field 317 or in this specific example a magnetic field barrier 430. High energy electrons are restricted from passing through the magnetic field barrier 430. In this manner, the magnetic field barrier 430 acts as a filter between, zone A and zone B, in the negative ion source. Preferably, a central magnetic material 410, which is an example of the magnetic material 316, is placed within the high temperature plasma region 490, such as along a central axis of the high temperature plasma region 490. Preferably, the first electrode 422 and second electrode 424 are composed of magnetic materials, such as iron. Preferably, the outer walls 450 of the high temperature plasma region, such as cylinder walls, are composed of a magnetic material, such as a permanent magnet, ferric or iron based material, or a ferrite dielectric ring magnet. In this manner a magnetic field loop is created by: the central magnetic material 410, first electrode 422, the outer walls 450, the second electrode 424, and the magnetic field barrier 430. Again, the magnetic field barrier 430 restricts high energy electrons from passing through the magnetic field barrier 430. Low energy electrons interact with atomic hydrogen, H0, to create a hydrogen anion, H−, in the low temperature plasma region 492. In the fourth stage, a second high voltage pulse or extraction pulse is applied at a third electrode 426. The second high voltage pulse is preferentially applied during the later period of application of the first high voltage pulse. For example, an extraction pulse of about 25 kV is applied for about the last 5 microseconds of the first creation pulse of about 20 microseconds. The potential difference, of about 20 kV, between the third electrode 426 and second electrode 424 extracts the negative ion, H−, from the low temperature plasma region 492 and initiates the negative ion beam 319, from zone B to zone C. The magnetic field barrier 430 is optionally created in number of ways. An example of creation of the magnetic field barrier 430 using coils is provided. In this example, the elements described, supra, in relation to FIG. 4 are maintained with several differences. First, the magnetic field is created using coils. An isolating material is preferably provided between the first electrode 422 and the cylinder walls 450 as well as between the second electrode 424 and the cylinder walls 450. The central material 410 and/or cylinder walls 450 are optionally metallic. In this manner, the coils create a magnetic field loop through the first electrode 422, isolating material, outer walls 450, second electrode 424, magnetic field barrier 430, and the central material 410. Essentially, the coils generate a magnetic field in place of production of the magnetic field by the magnetic material 410. The magnetic field barrier 430 operates as described, supra. Generally, any manner that creates the magnetic field barrier 430 between the high temperature plasma region 490 and low temperature plasma region 492 is functionally applicable to the ion beam extraction system 400, described herein. Ion Beam Focusing System Referring now to FIG. 5, the ion beam focusing system 350 is further described. In this example, three electrodes are used. In this example, a first electrode 510 and third electrode 530 are both negatively charged and each is a ring electrode circumferentially enclosing or at least partially enclosing the negative ion beam path 319. A second electrode 520 is positively charged and is also a ring electrode at least partially and preferably substantially circumferentially enclosing the negative ion beam path. In addition, the second electrode includes one or more conducting paths 372 running through the negative ion beam path 319. For example, the conducting paths are a wire mesh, a conducting grid, or a series of substantially parallel conducting lines running across the second electrode. In use, electric field lines run from the conducting paths of the positively charged electrode to the negatively charged electrodes. For example, in use the electric field lines 540 run from the conducting paths 372 in the negative ion beam path 319 to the negatively charged electrodes 510, 530. Two ray trace lines 550, 560 of the negative ion beam path are used to illustrate focusing forces. In the first ray trace line 550, the negative ion beam encounters a first electric field line at point M. Negatively charged ions in the negative ion beam 550 encounter forces running up the electric field line 572, illustrated with an x-axis component vector 571. The x-axis component force vectors 571 alters the trajectory of the first ray trace line to a inward focused vector 552, which encounters a second electric field line at point N. Again, the negative ion beam 552 encounters forces running up the electric field line 574, illustrated as having an inward force vector with an x-axis component 573, which alters the inward focused vector 552 to a more inward focused vector 554. Similarly, in the second ray trace line 560, the negative ion beam encounters a first electric field line at point O. Negatively charged ions in the negative ion beam encounter forces running up the electric field line 576, illustrated as having a force vector with an x-axis force 575. The inward force vector 575 alters the trajectory of the second ray trace line 560 to an inward focused vector 562, which encounters a second electric field line at point P. Again, the negative ion beam encounters forces running up the electric field line 578, illustrated as having force vector with an x-axis component 577, which alters the inward focused vector 562 to a more inward focused vector 564. The net result is a focusing effect on the negative ion beam. Each of the force vectors 572, 574, 576, 578 optionally has x and/or y force vector components resulting in a 3-dimensional focusing of the negative ion beam path. Naturally, the force vectors are illustrative in nature, many electric field lines are encountered, and the focusing effect is observed at each encounter resulting in integral focusing. The example is used to illustrate the focusing effect. Still referring to FIG. 5, optionally any number of electrodes are used, such as 2, 3, 4, 5, 6, 7, 8, or 9 electrodes, to focus the negative ion beam path where every other electrode, in a given focusing section, is either positively or negatively charged. For example, three focusing sections are optionally used. In the first ion focusing section 360, a pair of electrodes is used where the first electrode encountered along the negative ion beam path is negatively charged and the second electrode is positively charged, resulting in focusing of the negative ion beam path. In the second ion focusing section 370, two pairs of electrodes are used, where a common positively charged electrode with a conductive mesh running through the negatively ion beam path 319 is used. Thus, in the second ion focusing section 370, the first electrode encountered along the negative ion beam path is negatively charged and the second electrode is positively charged, resulting in focusing of the negative ion beam path. Further, in the second ion focusing section, moving along the negative ion beam path, a second focusing effect is observed between the second positively charged electrode and a third negatively charged electrode. In this example, a third ion focusing section is used that again has three electrodes, which acts in the fashion of the second ion focusing section, described supra. Referring now to FIGS. 6(A-D), the central region of the electrodes in the ion beam focusing system 350 is further described. Referring now to FIG. 6A, the central region of the negatively charged ring electrode 510 is preferably void of conductive material. Referring now to FIGS. 6(B-D), the central region of positively charged electrode ring 520 preferably contains conductive paths 372. Preferably, the conductive paths 372 or conductive material within the positively charged electrode ring 520 blocks about 1, 2, 5, or 10 percent of the area and more preferably blocks about five percent of the cross-sectional area of the negative ion beam path 319. Referring now to FIG. 6B, one option is a conductive mesh 610. Referring now to FIG. 6C, a second option is a series of conductive lines 620 running substantially in parallel across the positively charged electrode ring 520 that surrounds a portion of the negative ion beam path 319. Referring now to FIG. 6D, a third option is to have a foil 630 or metallic layer cover all of the cross-sectional area of the negative ion beam path with holes punched through the material, where the holes take up about 90-99 percent and more preferably about 95 percent of the area of the foil. More generally, the pair of electrodes 510, 520 are configured to provide electric field lines that provide focusing force vectors to the negative ion beam 319 when the ions in the negative ion beam 319 translate through the electric field lines, as described supra. In an example of a two electrode negative beam ion focusing system having a first cross-sectional diameter, d1, the negative ions are focused to a second cross-sectional diameter, d2, where d1>d2. Similarly, in an example of a three electrode negative beam ion focusing system having a first ion beam cross-sectional diameter, d1, the negative ions are focused using the three electrode system to a third negative ion beam cross-sectional diameter, d3, where d1>d3. For like potentials on the electrodes, the three electrode system provides tighter or stronger focusing compared to the two-electrode system, d3<d2. In the examples provided, supra, of a multi-electrode ion beam focusing system, the electrodes are rings. More generally, the electrodes are of any geometry sufficient to provide electric field lines that provide focusing force vectors to the negative ion beam when the ions in the negative ion beam 319 translate through the electric field lines, as described supra. For example, one negative ring electrode is optionally replaced by a number of negatively charged electrodes, such as about 2, 3, 4, 6, 8, 10, or more electrodes placed about the outer region of a cross-sectional area of the negative ion beam probe. Generally, more electrodes are required to converge or diverge a faster or higher energy beam. In another embodiment, by reversing the polarity of electrodes in the above example, the negative ion beam is made to diverge. Thus, the negative ion beam path 319 is optionally focused and/or expanded using combinations of electrode pairs. For example, if the electrode having the mesh across the negative ion beam path is made negative, then the negative ion beam path is made to defocus. Hence, combinations of electrode pairs are used for focusing and defocusing a negative ion beam path, such as where a first pair includes a positively charged mesh for focusing and a where a second pair includes a negatively charged mesh for defocusing. Tandem Accelerator Referring now to FIG. 7A, the tandem accelerator 390 is further described. The tandem accelerator accelerates ions using a series of electrodes 710, 711, 712, 713, 714, 715. For example, negative ions, such as H−, in the negative ion beam path are accelerated using a series of electrodes having progressively higher voltages relative to the voltage of the extraction electrode 426, or third electrode 426, of the negative ion beam source 310. For instance, the tandem accelerator 390 optionally has electrodes ranging from the 25 kV of the extraction electrode 426 to about 525 kV near the foil 395 in the tandem accelerator 390. Upon passing through the foil 395, the negative ion, H−, loses two electrons to yield a proton, H+, according to equation 1.H−→H++2e− (eq. 1) The proton is further accelerated in the tandem accelerator using appropriate voltages at a multitude of further electrodes 713, 714, 715. The protons are then injected into the synchrotron 130 as described, supra. Still referring to FIG. 7A, the foil 395 in the tandem accelerator 390 is further described. The foil 395 is preferably a very thin carbon film of about thirty to two hundred angstroms in thickness. The foil thickness is designed to both: (1) not block the ion beam and (2) allow the transfer of electrons yielding protons to form the proton beam path 262. The foil 395 is preferably substantially in contact with a support layer 720, such as a support grid. The support layer 720 provides mechanical strength to the foil 395 to combine to form a vacuum blocking element 725. The foil 395 blocks nitrogen, carbon dioxide, hydrogen, and other gases from passing and thus acts as a vacuum barrier. In one embodiment, the foil 395 is preferably sealed directly or indirectly to the edges of the vacuum tube 320 providing for a higher pressure, such as about 10−5 torr, to be maintained on the side of the foil 395 having the negative ion beam path 319 and a lower pressure, such as about 10−7 torr, to be maintained on the side of the foil 395 having the proton ion beam path 262. Having the foil 395 physically separating the vacuum chamber 320 into two pressure regions allows for a vacuum system having fewer and/or smaller pumps to maintain the lower pressure system in the synchrotron 130 as the inlet hydrogen and its residuals are extracted in a separate contained and isolated space by the first partial vacuum system 330. The foil 395 and support layer 720 are preferably attached to the structure 750 of the tandem accelerator 390 or vacuum tube 320 to form a pressure barrier using any mechanical means, such as a metal, plastic, or ceramic ring 730 compressed to the walls with an attachment screw 740. Any mechanical means for separating and sealing the two vacuum chamber sides with the foil 395 are equally applicable to this system. Referring now to FIG. 7B and FIG. 7C, the support structure 720 and foil 395 are, respectively, individually viewed in the x-, y-plane. Referring now to FIG. 8, another exemplary method of use of the charged particle beam system 100 is provided. The main controller 110, or one or more sub-controllers, controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller sends a message to the patient indicating when or how to breathe. The main controller 110 obtains a sensor reading from the patient interface module, such as a temperature breath sensor or a force reading indicative of where in a respiration cycle the subject is. Coordinated at a specific and reproducible point in the respiration cycle, the main controller collects an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 then optionally controls the injection system 120 to inject hydrogen gas into a negative ion beam source 310 and controls timing of extraction of the negative ion from the negative ion beam source 310. Optionally, the main controller controls ion beam focusing using the ion beam focusing lens system 350; acceleration of the proton beam with the tandem accelerator 390; and/or injection of the proton into the synchrotron 130. The synchrotron typically contains at least an accelerator system 132 and an extraction system 134. The synchrotron preferably contains one or more of: turning magnets, edge focusing magnets, magnetic field concentration magnets, winding and correction coils, and flat magnetic field incident surfaces, some of which contain elements under control by the main controller 110. The main controller preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and/or timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The main controller 110 also preferably controls targeting of the proton beam through the targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150 are preferably controlled by the main controller 110, such as vertical position of the patient, rotational position of the patient, and patient chair positioning/stabilization/immobilization/control elements. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient. A radio frequency quadrupole (RFQ) accelerator 4850 is optionally used as an injector of charged particles to the synchrotron. For example, the RFQ accelerator is a 1.6 MeV RFQ accelerator used as an injector for a synchrotron and a buncher/debuncher cavity as necessary. The RFQ accelerator optionally operates at 425±0.05 MHz, has an ion injector output energy of about 30 keV, has an RFQ output energy of nominally 1/60±0.01 MeV, has a maximum pulsed output current of f10 mA, an output beam pulse flat-top width of 1-5 microseconds, and a beam pulse repetition rate of 0.1 to 20 Hz. Synchrotron Herein, the term synchrotron is used to refer to a system maintaining the charged particle beam in a circulating path. Further, the charged particle beam is referred to herein as circulating along a circulating path about a central point of the synchrotron. The circulating path is alternatively referred to as an orbiting path; however, the orbiting path does not refer to a perfect circle or ellipse, rather it refers to cycling of the protons around a central point or region 280. Circulating System Referring now to FIG. 9, the synchrotron 130 preferably comprises a combination of straight sections 910 and ion beam turning sections 920. Hence, the circulating path of the protons is not circular in a synchrotron, but is rather a polygon with rounded corners. In one illustrative embodiment, the synchrotron 130, which is also referred to as an accelerator system, has four straight sections or elements and four turning sections. Examples of straight sections 910 include the: inflector 240, accelerator 270, extraction system 290, and deflector 292. Along with the four straight sections are four ion beam turning sections 920, which are also referred to as magnet sections or turning sections. Turning sections are further described, infra. Referring still to FIG. 9, an exemplary synchrotron is illustrated. In this example, protons delivered along the initial proton beam path 262 are inflected into the circulating beam path with the inflector 240 and after acceleration are extracted via a deflector 292 to the beam transport path 268. In this example, the synchrotron 130 comprises four straight sections 910 and four bending or turning sections 920 where each of the four turning sections use one or more magnets to turn the proton beam about ninety degrees. As is further described, infra, the ability to closely space the turning sections and efficiently turn the proton beam results in shorter straight sections. Shorter straight sections allow for a synchrotron design without the use of focusing quadrupoles in the circulating beam path of the synchrotron. The removal of the focusing quadrupoles from the circulating proton beam path results in a more compact design. In this example, the illustrated synchrotron has about a five meter diameter versus eight meter and larger cross-sectional diameters for systems using a quadrupole focusing magnet in the circulating proton beam path. Referring now to FIG. 10, additional description of the first bending or turning section 920 is provided. Each of the turning sections preferably comprise multiple magnets, such as about 2, 4, 6, 8, 10, or 12 magnets. In this example, four turning magnets 1010, 1020, 1030, 1040 in the first turning section 920 are used to illustrate key principles, which are the same regardless of the number of magnets in a turning section 920. The turning magnets 1010, 1020, 1030, 1040 are particular types of main bending or circulating magnets 250. In physics, the Lorentz force is the force on a point charge due to electromagnetic fields. The Lorentz force is given by equation 2 in terms of magnetic fields with the electron field terms not included.F=q(v×B) (eq. 2) In equation 2, F is the force in newtons; q is the electric charge in coulombs; B is the magnetic field in Teslas; and v is the instantaneous velocity of the particles in meters per second. Referring now to FIG. 11, an example of a single magnet bending or turning section 1010 is expanded. The turning section includes a gap 1110 through which protons circulate. The gap 1110 is preferably a flat gap, allowing for a magnetic field across the gap 1110 that is more uniform, even, and intense. A magnetic field enters the gap 1110 through a magnetic field incident surface and exits the gap 1110 through a magnetic field exiting surface. The gap 1110 runs in a vacuum tube between two magnet halves. The gap 1110 is controlled by at least two parameters: (1) the gap 1110 is kept as large as possible to minimize loss of protons and (2) the gap 1110 is kept as small as possible to minimize magnet sizes and the associated size and power requirements of the magnet power supplies. The flat nature of the gap 1110 allows for a compressed and more uniform magnetic field across the gap 1110. One example of a gap dimension is to accommodate a vertical proton beam size of about two centimeters with a horizontal beam size of about five to six centimeters. As described, supra, a larger gap size requires a larger power supply. For instance, if the gap 1110 size doubles in vertical size, then the power supply requirements increase by about a factor of four. The flatness of the gap 1110 is also important. For example, the flat nature of the gap 1110 allows for an increase in energy of the extracted protons from about 250 to about 330 MeV. More particularly, if the gap 1110 has an extremely flat surface, then the limits of a magnetic field of an iron magnet are reachable. An exemplary precision of the flat surface of the gap 1110 is a polish of less than about five microns and preferably with a polish of about one to three microns. Unevenness in the surface results in imperfections in the applied magnetic field. The polished flat surface spreads unevenness of the applied magnetic field. Still referring to FIG. 11, the charged particle beam moves through the gap 1110 with an instantaneous velocity, v. A first magnetic coil 1120 and a second magnetic coil 1130 run above and below the gap 1110, respectively. Current running through the coils 1120, 1130 results in a magnetic field, B, running through the single magnet turning section 1010. In this example, the magnetic field, B, runs upward, which results in a force, F, pushing the charged particle beam inward toward a central point of the synchrotron, which turns the charged particle beam in an arc. Still referring to FIG. 11, a portion of an optional second magnet bending or turning section 1020 is illustrated. The coils 1120, 1130 typically have return elements 1140, 1150 or turns at the end of one magnet, such as at the end of the first magnet turning section 1010. The turns 1140, 1150 take space. The space reduces the percentage of the path about one orbit of the synchrotron that is covered by the turning magnets. This leads to portions of the circulating path where the protons are not turned and/or focused and allows for portions of the circulating path where the proton path defocuses. Thus, the space results in a larger synchrotron. Therefore, the space between magnet turning sections 1160 is preferably minimized. The second turning magnet is used to illustrate that the coils 1120, 1130 optionally run along a plurality of magnets, such as 2, 3, 4, 5, 6, or more magnets. Coils 1120, 1130 running across multiple turning section magnets allows for two turning section magnets to be spatially positioned closer to each other due to the removal of the steric constraint of the turns, which reduces and/or minimizes the space 1160 between two turning section magnets. Referring now to FIG. 12 and FIG. 13, two illustrative 90 degree rotated cross-sections of single magnet bending or turning sections 1010 are presented. The magnet assembly has a first magnet 1210 and a second magnet 1220. A magnetic field induced by coils, described infra, runs between the first magnet 1210 to the second magnet 1220 across the gap 1110. Return magnetic fields run through a first yoke 1212 and second yoke 1222. The combined cross-section area of the return yokes roughly approximates the cross-sectional area of the first magnet 1210 or second magnet 1220. The charged particles run through the vacuum tube in the gap 1110. As illustrated, protons run into FIG. 12 through the gap 1110 and the magnetic field, illustrated as vector B, applies a force F to the protons pushing the protons towards the center of the synchrotron, which is off page to the right in FIG. 12. The magnetic field is created using windings. A first coil is used to form a first winding coil 1250 and a second coil of wire is used to form a second winding coil 1260. Isolating or concentrating gaps 1230, 1240, such as air gaps, isolate the iron based yokes from the gap 1110. The gap 1110 is approximately flat to yield a uniform magnetic field across the gap 1110, as described supra. Still referring to FIG. 13, the ends of a single bending or turning magnet are preferably beveled. Nearly perpendicular or right angle edges of a turning magnet 1010 are represented by dashed lines 1374, 1384. The dashed lines 1374, 1384 intersect at a point 1390 beyond the center of the synchrotron 280. Preferably, the edge of the turning magnet is beveled at angles alpha, α, and beta, β, which are angles formed by a first line 1372, 1382 going from an edge of the turning magnet 1010 and the center 280 and a second line 1374, 1384 going from the same edge of the turning magnet and the intersecting point 1390. The angle alpha is used to describe the effect and the description of angle alpha applies to angle beta, but angle alpha is optionally different from angle beta. The angle alpha provides an edge focusing effect. Beveling the edge of the turning magnet 1010 at angle alpha focuses the proton beam. Multiple turning magnets provide multiple magnet edges that each have edge focusing effects in the synchrotron 130. If only one turning magnet is used, then the beam is only focused once for angle alpha or twice for angle alpha and angle beta. However, by using smaller turning magnets, more turning magnets fit into the turning sections 920 of the synchrotron 130. For example, if four magnets are used in a turning section 920 of the synchrotron, then for a single turning section there are eight possible edge focusing effect surfaces, two edges per magnet. The eight focusing surfaces yield a smaller cross-sectional beam size, which allows the use of a smaller gap. The use of multiple edge focusing effects in the turning magnets results in not only a smaller gap 1110, but also the use of smaller magnets and smaller power supplies. For a synchrotron 130 having four turning sections 920 where each turning sections has four turning magnets and each turning magnet has two focusing edges, a total of thirty-two focusing edges exist for each orbit of the protons in the circulating path of the synchrotron 130. Similarly, if 2, 6, or 8 magnets are used in a given turning section, or if 2, 3, 5, or 6 turning sections are used, then the number of edge focusing surfaces expands or contracts according to equation 3. TFE = NTS * M NTS * FE M ( eq . ⁢ 3 ) where TFE is the number of total focusing edges, NTS is the number of turning sections, M is the number of magnets, and FE is the number of focusing edges. Naturally, not all magnets are necessarily beveled and some magnets are optionally beveled on only one edge. The inventors have determined that multiple smaller magnets have benefits over fewer larger magnets. For example, the use of 16 small magnets yields 32 focusing edges whereas the use of 4 larger magnets yields only 8 focusing edges. The use of a synchrotron having more focusing edges results in a circulating path of the synchrotron built without the use of focusing quadrupole magnets. All prior art synchrotrons use quadrupoles in the circulating path of the synchrotron. Further, the use of quadrupoles in the circulating path necessitates additional straight sections in the circulating path of the synchrotron. Thus, the use of quadrupoles in the circulating path of a synchrotron results in synchrotrons having larger diameters, larger circulating beam pathlengths, and/or larger circumferences. In various embodiments of the system described herein, the synchrotron has any combination of: at least four and preferably six, eight, ten, or more edge focusing edges per 90 degrees of turn of the charged particle beam in a synchrotron having four turning sections; at least about sixteen and preferably about twenty-four, thirty-two, or more edge focusing edges per orbit of the charged particle beam in the synchrotron; only four turning sections where each of the turning sections includes at least four and preferably eight edge focusing edges; an equal number of straight sections and turning sections; exactly four turning sections; at least four focusing edges per turning section; no quadrupoles in the circulating path of the synchrotron; a rounded corner rectangular polygon configuration; a circumference of less than sixty meters; a circumference of less than sixty meters and thirty-two edge focusing surfaces; and/or any of about eight, sixteen, twenty-four, or thirty-two non-quadrupole magnets per circulating path of the synchrotron, where the non-quadrupole magnets include edge focusing edges. Flat Gap Surface While the gap surface is described in terms of the first turning magnet 1010, the discussion applies to each of the turning magnets in the synchrotron. Similarly, while the gap 1110 surface is described in terms of the magnetic field incident surface 1270, the discussion additionally optionally applies to the magnetic field exiting surface 1280. Referring again to FIG. 12, the incident magnetic field surface 1270 of the first magnet 1210 is further described. FIG. 12 is not to scale and is illustrative in nature. Local imperfections or unevenness in quality of the finish of the incident surface 1270 results in inhomogeneities or imperfections in the magnetic field applied to the gap 1110. The magnetic field incident surface 1270 and/or exiting surface 1280 of the first magnet 1210 is preferably about flat, such as to within about a zero to three micron finish polish or less preferably to about a ten micron finish polish. By being very flat, the polished surface spreads the unevenness of the applied magnetic field across the gap 1110. The very flat surface, such as about 0, 1, 2, 4, 6, 8, 10, 15, or 20 micron finish, allows for a smaller gap size, a smaller applied magnetic field, smaller power supplies, and tighter control of the proton beam cross-sectional area. Referring now to FIG. 14, additional optional magnet elements, of the magnet cross-section illustratively represented in FIG. 12, are described. The first magnet 1210 preferably contains an initial cross-sectional distance 1410 of the iron based core. The contours of the magnetic field are shaped by the magnets 1210, 1220 and the yokes 1212, 1222. The iron based core tapers to a second cross-sectional distance 1420. The shape of the magnetic field vector 1440 is illustrative only. The magnetic field in the magnet preferentially stays in the iron based core as opposed to the gaps 1230, 1240. As the cross-sectional distance decreases from the initial cross-sectional distance 1410 to the final cross-sectional distance 1420, the magnetic field concentrates. The change in shape of the magnet from the longer distance 1410 to the smaller distance 1420 acts as an amplifier. The concentration of the magnetic field is illustrated by representing an initial density of magnetic field vectors 1430 in the initial cross-section 1410 to a concentrated density of magnetic field vectors 1440 in the final cross-section 1420. The concentration of the magnetic field due to the geometry of the turning magnets results in fewer winding coils 1250, 1260 being required and also a smaller power supply to the coils being required. In one example, the initial cross-section distance 1410 is about fifteen centimeters and the final cross-section distance 1420 is about ten centimeters. Using the provided numbers, the concentration of the magnetic field is about 15/10 or 1.5 times at the incident surface 1270 of the gap 1110, though the relationship is not linear. The taper 1460 has a slope, such as about twenty, forty, or sixty degrees. The concentration of the magnetic field, such as by 1.5 times, leads to a corresponding decrease in power consumption requirements to the magnets. Referring now to FIG. 15, an additional example of geometry of the magnet used to concentrate the magnetic field is illustrated. As illustrated in FIG. 14, the first magnet 1210 preferably contains an initial cross-sectional distance 1410 of the iron based core. The contours of the magnetic field are shaped by the magnets 1210, 1220 and the yokes 1212, 1222. In this example, the core tapers to a second cross-sectional distance 1420 with a smaller angle theta, θ. As described, supra, the magnetic field in the magnet preferentially stays in the iron based core as opposed to the gaps 1230, 1240. As the cross-sectional distance decreases from the initial cross-sectional distance 1410 to the final cross-sectional distance 1420, the magnetic field concentrates. The smaller angle, theta, results in a greater amplification of the magnetic field in going from the longer distance 1410 to the smaller distance 1420. The concentration of the magnetic field is illustrated by representing an initial density of magnetic field vectors 1430 in the initial cross-section 1410 to a concentrated density of magnetic field vectors 1440 in the final cross-section 1420. The concentration of the magnetic field due to the geometry of the turning magnets results in fewer winding coils 1250, 1260 being required and also a smaller power supply to the winding coils 1250, 1260 being required. Still referring to FIG. 15, optional correction coils 1510, 1520 are illustrated that are used to correct the strength of one or more turning magnets. The correction coils 1520, 1530 supplement the winding coils 1250, 1260. The correction coils 1510, 1520 have correction coil power supplies that are separate from winding coil power supplies used with the winding coils 1250, 1260. The correction coil power supplies typically operate at a fraction of the power required compared to the winding coil power supplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power and more preferably about 1 or 2 percent of the power used with the winding coils 1250, 1260. The smaller operating power applied to the correction coils 1510, 1520 allows for more accurate and/or precise control of the correction coils. The correction coils are used to adjust for imperfection in the turning magnets. Optionally, separate correction coils are used for each turning magnet allowing individual tuning of the magnetic field for each turning magnet, which eases quality requirements in the manufacture of each turning magnet. Referring now to FIG. 16, an example of winding coils 1630 and correction coils 1620 about a plurality of turning magnets 1010, 1020 in an ion beam turning section 920 is illustrated. The winding coils preferably cover 1, 2, or 4 turning magnets. One or more high precision magnetic field sensors 1650 are placed into the synchrotron and are used to measure the magnetic field at or near the proton beam path. For example, the magnetic sensors are optionally placed between turning magnets and/or within a turning magnet, such as at or near the gap 1110 or at or near the magnet core or yoke. The sensors are part of a feedback system to the correction coils, which is optionally run by the main controller. Thus, the system preferably stabilizes the magnetic field in the synchrotron rather than stabilizing the current applied to the magnets. Stabilization of the magnetic field allows the synchrotron to come to a new energy level quickly. This allows the system to be controlled to an operator or algorithm selected energy level with each pulse of the synchrotron and/or with each breath of the patient. The winding and/or correction coils correct one, two, three, or four turning magnets, and preferably correct a magnetic field generated by two turning magnets. Optionally, a correction coil 1640 winds a single magnet section 1010 or a correction coil 1620 winds two or more magnet turning sections 1010, 1020. A winding or correction coil covering multiple magnets reduces space between magnets as fewer winding or correction coil ends are required, which occupy space. Reduction of space between turning magnets allows operation of the turning magnets with smaller power supplies and optionally without quadrupole magnet focusing sections. Space 1160 at the end of a turning magnets 1010, 1040 is optionally further reduced by changing the cross-sectional shape of the winding coils. For example, when the winding coils are running longitudinally along the length of the circulating path or along the length of the turning magnet, the cross-sectional dimension is thick and when the winding coils turn at the end of a turning magnet to run axially across the winding coil, then the cross-sectional area of the winding coils is preferably thin. For example, the cross-sectional area of winding coils as measured by an m×n matrix is 3×2 running longitudinally along the turning magnet and 6×1 running axially at the end of the turning magnet, thereby reducing the width of the coils, n, while keeping the number of coils constant. Preferably, the turn from the longitudinal to axial direction of the winding coil approximates ninety degrees by cutting each winding and welding each longitudinal section to the connecting axial section at about a ninety degree angle. The nearly perpendicular weld further reduces space requirements of the turn in the winding coil, which reduces space in circulating orbit not experiencing focusing and turning forces, which reduces the size of the synchrotron. Still referring to FIG. 16 and now additionally referring to FIG. 2, FIG. 9, and FIG. 10, an optional modular magnet system is described. As illustrated in FIG. 2, the synchrotron 130 optionally uses sixteen main bending magnets 250. As illustrated in FIG. 9 and FIG. 10, in one case, the sixteen main bending magnets are organized into four beam turning sections 920, where each of the four beam turning sections, as described supra, contain a group of four turning magnets 1010, 1020, 1030, 1040. Now referring to FIG. 16, the winding coil 1630 is illustrated as optionally connecting a sub-group of two turning magnets 1010, 1020. The sub-group of two turning magnets optionally uses a common winding coil for the two turning magnets. The sub-group using a common coil for two magnets is optionally repeated twice in one turning section to form four magnets, is repeated eight times in the synchrotron to form eight groups of two magnets, where two sub-groups of two turning magnets are used in each turning section 920, and/or is repeated n times where n is a positive integer. Generally, the sub-group of two magnets wound with a common winding coil is a building block used to build a synchrotron. Having one sub-group of magnets that is used multiple times in the synchrotron reduces manufacturing costs, simplifies quality control and/or quality assurance procedures, and simplifies inspection. Referring now to FIG. 17A and FIG. 17B, the accelerator system 270, such as a radio-frequency (RF) accelerator system, is further described. The accelerator includes a series of coils 1710-1719, such as iron or ferrite coils, each circumferentially enclosing the vacuum system 320 through which the proton beam 264 passes in the synchrotron 130. Referring now to FIG. 17B, the first coil 1710 is further described. A loop of standard wire 1730 completes at least one turn about the first coil 1710. The loop attaches to a microcircuit 1720. Referring again to FIG. 17A, an RF synthesizer 1740, which is preferably connected to the main controller 110, provides a low voltage RF signal that is synchronized to the period of circulation of protons in the proton beam path 264. The RF synthesizer 1740, microcircuit 1720, loop 1730, and coil 1710 combine to provide an accelerating voltage to the protons in the proton beam path 264. For example, the RF synthesizer 1740 sends a signal to the microcircuit 1720, which amplifies the low voltage RF signal and yields an acceleration voltage, such as about 10 volts. The actual acceleration voltage for a single microcircuit/loop/coil combination is about five, ten, fifteen, or twenty volts, but is preferably about ten volts. Preferably, the RF-amplifier microcircuit and accelerating coil are integrated. Still referring to FIG. 17A, the integrated RF-amplifier microcircuit and accelerating coil presented in FIG. 17B is repeated, as illustrated as the set of coils 1711-1719 surrounding the vacuum tube 320. For example, the RF-synthesizer 1740, under main controller 130 direction, sends an RF-signal to the microcircuits 1720-1729 connected to coils 1710-1719, respectively. Each of the microcircuit/loop/coil combinations generates a proton accelerating voltage, such as about ten volts each. Hence, a set of five coil combinations generates about fifty volts for proton acceleration. Preferably about five to twenty microcircuit/loop/coil combinations are used and more preferably about nine or ten microcircuit/loop/coil combinations are used in the accelerator system 270. As a further clarifying example, the RF synthesizer 1740 sends an RF-signal, with a period equal to a period of circulation of a proton about the synchrotron 130, to a set of ten microcircuit/loop/coil combinations, which results in about 100 volts for acceleration of the protons in the proton beam path 264. The 100 volts is generated at a range of frequencies, such as at about one MHz for a low energy proton beam to about fifteen MHz for a high energy proton beam. The RF-signal is optionally set at an integer multiple of a period of circulation of the proton about the synchrotron circulating path. Each of the microcircuit/loop/coil combinations are optionally independently controlled in terms of acceleration voltage and frequency. Integration of the RF-amplifier microcircuit and accelerating coil, in each microcircuit/loop/coil combination, results in three considerable advantages. First, for synchrotrons, the prior art does not use microcircuits integrated with the accelerating coils but rather uses a set of long cables to provide power to a corresponding set of coils. The long cables have an impedance/resistance, which is problematic for high frequency RF control. As a result, the prior art system is not operable at high frequencies, such as above about ten MHz. The integrated RF-amplifier microcircuit/accelerating coil system is operable at above about ten MHz and even fifteen MHz where the impedance and/or resistance of the long cables in the prior art systems results in poor control or failure in proton acceleration. Second, the long cable system, operating at lower frequencies, costs about $50,000 and the integrated microcircuit system costs about $1000, which is fifty times less expensive. Third, the microcircuit/loop/coil combinations in conjunction with the RF-amplifier system results in a compact low power consumption design allowing production and use of a proton cancer therapy system in a small space, as described supra, and in a cost effective manner. Referring again to FIG. 16, an example of a winding coil 1630 that covers two turning magnets 1010, 1020 is provided. Optionally, a first winding coil 1640 covers two magnets 1010, 1020 and a second winding coil, not illustrated, covers another two magnets 1030, 1040. As described, supra, this system reduces space between turning section allowing more magnetic field to be applied per radian of turn. A first correction coil 1640 is illustrated that is used to correct the magnetic field for the first turning magnet 1010. A second correction coil 1620 is illustrated that is used to correct the magnetic field for a winding coil 1630 about two turning magnets. Individual correction coils for each turning magnet are preferred and individual correction coils yield the most precise and/or accurate magnetic field in each turning section. Particularly, an individual correction coil is preferably used to compensate for imperfections in the individual magnet of a given turning section. Hence, with a series of magnetic field sensors, corresponding magnetic fields are individually adjustable in a series of feedback loops, via a magnetic field monitoring system, as an independent coil is used for each turning section. Alternatively, a multiple magnet correction coil is used to correct the magnetic field for a plurality of turning section magnets. Proton Beam Extraction Referring now to FIG. 18, an exemplary proton beam extraction process 1800 from the synchrotron 130 is illustrated. For clarity, FIG. 18 removes elements represented in FIG. 2, such as the turning magnets, which allows for greater clarity of presentation of the proton beam path as a function of time. Generally, protons are extracted from the synchrotron 130 by slowing the protons. As described, supra, the protons were initially accelerated in a circulating path 264, which is maintained with a plurality of main bending magnets 250. The circulating path is referred to herein as an original central beamline 264. The protons repeatedly cycle around a central point in the synchrotron 280. The proton path traverses through a radio frequency (RF) cavity system 1910. To initiate extraction, an RF field is applied across a first blade 1912 and a second blade 1914, in the RF cavity system 1910. The first blade 1912 and second blade 1914 are referred to herein as a first pair of blades. In the proton extraction process, an RF voltage is applied across the first pair of blades, where the first blade 1912 of the first pair of blades is on one side of the circulating proton beam path 264 and the second blade 1914 of the first pair of blades is on an opposite side of the circulating proton beam path 264. The applied RF field applies energy to the circulating charged-particle beam. The applied RF field alters the orbiting or circulating beam path slightly of the protons from the original central beamline 264 to an altered circulating beam path 265. Upon a second pass of the protons through the RF cavity system, the RF field further moves the protons off of the original proton beamline 264. For example, if the original beamline is considered as a circular path, then the altered beamline is slightly elliptical. The applied RF field is timed to apply outward or inward movement to a given band of protons circulating in the synchrotron accelerator. Each orbit of the protons is slightly more off axis compared to the original circulating beam path 264. Successive passes of the protons through the RF cavity system are forced further and further from the original central beamline 264 by altering the direction and/or intensity of the RF field with each successive pass of the proton beam through the RF field. The RF voltage is frequency modulated at a frequency about equal to the period of one proton cycling around the synchrotron for one revolution or at a frequency than is an integer multiplier of the period of one proton cycling about the synchrotron. The applied RF frequency modulated voltage excites a betatron oscillation. For example, the oscillation is a sine wave motion of the protons. The process of timing the RF field to a given proton beam within the RF cavity system is repeated thousands of times with each successive pass of the protons being moved approximately one micrometer further off of the original central beamline 264. For clarity, the approximately 1000 changing beam paths with each successive path of a given band of protons through the RF field are illustrated as the altered beam path 265. With a sufficient sine wave betatron amplitude, the altered circulating beam path 265 touches and/or traverses a material 1930, such as a foil or a sheet of foil. The foil is preferably a lightweight material, such as beryllium, a lithium hydride, a carbon sheet, or a material having low nuclear charge components. Herein, a material of low nuclear charge is a material composed of atoms consisting essentially of atoms having six or fewer protons. The foil is preferably about 10 to 150 microns thick, is more preferably about 30 to 100 microns thick, and is still more preferably about 40 to 60 microns thick. In one example, the foil is beryllium with a thickness of about 50 microns. When the protons traverse through the foil, energy of the protons is lost and the speed of the protons is reduced. Typically, a current is also generated, described infra. Protons moving at a slower speed travel in the synchrotron with a reduced radius of curvature 266 compared to either the original central beamline 264 or the altered circulating path 265. The reduced radius of curvature 266 path is also referred to herein as a path having a smaller diameter of trajectory or a path having protons with reduced energy. The reduced radius of curvature 266 is typically about two millimeters less than a radius of curvature of the last pass of the protons along the altered proton beam path 265. The thickness of the material 1930 is optionally adjusted to created a change in the radius of curvature, such as about ½, 1, 2, 3, or 4 mm less than the last pass of the protons 265 or original radius of curvature 264. Protons moving with the smaller radius of curvature travel between a second pair of blades. In one case, the second pair of blades is physically distinct and/or is separated from the first pair of blades. In a second case, one of the first pair of blades is also a member of the second pair of blades. For example, the second pair of blades is the second blade 1914 and a third blade 1916 in the RF cavity system 1910. A high voltage DC signal, such as about 1 to 5 kV, is then applied across the second pair of blades, which directs the protons out of the synchrotron through an extraction magnet 292, such as a Lamberson extraction magnet, into a transport path 268. Control of acceleration of the charged particle beam path in the synchrotron with the accelerator and/or applied fields of the turning magnets in combination with the above described extraction system allows for control of the intensity of the extracted proton beam, where intensity is a proton flux per unit time or the number of protons extracted as a function of time. For example, when a current is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In another embodiment, instead of moving the charged particles to the material 1930, the material 1930 is mechanically moved to the circulating charged particles. Particularly, the material 1930 is mechanically or electromechanically translated into the path of the circulating charged particles to induce the extraction process, described supra. In either case, because the extraction system does not depend on any change in magnetic field properties, it allows the synchrotron to continue to operate in acceleration or deceleration mode during the extraction process. Stated differently, the extraction process does not interfere with synchrotron acceleration. In stark contrast, traditional extraction systems introduce a new magnetic field, such as via a hexapole, during the extraction process. More particularly, traditional synchrotrons have a magnet, such as a hexapole magnet, that is off during an acceleration stage. During the extraction phase, the hexapole magnetic field is introduced to the circulating path of the synchrotron. The introduction of the magnetic field necessitates two distinct modes, an acceleration mode and an extraction mode, which are mutually exclusive in time. The herein described system allows for acceleration and/or deceleration of the proton during the extraction step without the use of a newly introduced magnetic field, such as by a hexapole magnet. Charged Particle Beam Intensity Control Control of applied field, such as a radio-frequency (RF) field, frequency and magnitude in the RF cavity system 1910 allows for intensity control of the extracted proton beam, where intensity is extracted proton flux per unit time or the number of protons extracted as a function of time. Referring now to FIG. 19, an intensity control system 1900 is illustrated. In this example, an intensity control feedback loop is added to the extraction system, described supra. When protons in the proton beam hit the material 1930 electrons are given off resulting in a current. The resulting current is converted to a voltage and is used as part of a ion beam intensity monitoring system or as part of an ion beam feedback loop for controlling beam intensity. The voltage is optionally measured and sent to the main controller 110 or to an intensity controller subsystem 1940, which is preferably in communication or under the direction of the main controller 110. More particularly, when protons in the charged particle beam path pass through the material 1930, some of the protons lose a small fraction of their energy, such as about one-tenth of a percent, which results in a secondary electron. That is, protons in the charged particle beam push some electrons when passing through material 1930 giving the electrons enough energy to cause secondary emission. The resulting electron flow results in a current or signal that is proportional to the number of protons going through the target material 1930. The resulting current is preferably converted to voltage and amplified. The resulting signal is referred to as a measured intensity signal. The amplified signal or measured intensity signal resulting from the protons passing through the material 1930 is optionally used in monitoring the intensity of the extracted protons and is preferably used in controlling the intensity of the extracted protons. For example, the measured intensity signal is compared to a goal signal, which is predetermined in an irradiation of the tumor plan. The difference between the measured intensity signal and the planned for goal signal is calculated. The difference is used as a control to the RF generator. Hence, the measured flow of current resulting from the protons passing through the material 1930 is used as a control in the RF generator to increase or decrease the number of protons undergoing betatron oscillation and striking the material 1930. Hence, the voltage determined off of the material 1930 is used as a measure of the orbital path and is used as a feedback control to control the RF cavity system. In one example, the intensity controller subsystem 1940 preferably additionally receives input from: (1) a detector 1950, which provides a reading of the actual intensity of the proton beam and (2) an irradiation plan 1960. The irradiation plan provides the desired intensity of the proton beam for each x, y, energy, and/or rotational position of the patient/tumor as a function of time. Thus, the intensity controller 1940 receives the desired intensity from the irradiation plan 1950, the actual intensity from the detector 1950 and/or a measure of intensity from the material 1930, and adjusts the radio-frequency field in the RF cavity system 1910 to yield an intensity of the proton beam that matches the desired intensity from the irradiation plan 1960. As described, supra, the photons striking the material 1930 is a step in the extraction of the protons from the synchrotron 130. Hence, the measured intensity signal is used to change the number of protons per unit time being extracted, which is referred to as intensity of the proton beam. The intensity of the proton beam is thus under algorithm control. Further, the intensity of the proton beam is controlled separately from the velocity of the protons in the synchrotron 130. Hence, intensity of the protons extracted and the energy of the protons extracted are independently variable. For example, protons initially move at an equilibrium trajectory in the synchrotron 130. An RF field is used to excite the protons into a betatron oscillation. In one case, the frequency of the protons orbit is about 10 MHz. In one example, in about one millisecond or after about 10,000 orbits, the first protons hit an outer edge of the target material 130. The specific frequency is dependent upon the period of the orbit. Upon hitting the material 130, the protons push electrons through the foil to produce a current. The current is converted to voltage and amplified to yield a measured intensity signal. The measured intensity signal is used as a feedback input to control the applied RF magnitude, RF frequency, or RF field. Preferably, the measured intensity signal is compared to a target signal and a measure of the difference between the measured intensity signal and target signal is used to adjust the applied RF field in the RF cavity system 1910 in the extraction system to control the intensity of the protons in the extraction step. Stated again, the signal resulting from the protons striking and/or passing through the material 130 is used as an input in RF field modulation. An increase in the magnitude of the RF modulation results in protons hitting the foil or material 130 sooner. By increasing the RF, more protons are pushed into the foil, which results in an increased intensity, or more protons per unit time, of protons extracted from the synchrotron 130. In another example, a detector 1950 external to the synchrotron 130 is used to determine the flux of protons extracted from the synchrotron and a signal from the external detector is used to alter the RF field or RF modulation in the RF cavity system 1910. Here the external detector generates an external signal, which is used in a manner similar to the measured intensity signal, described in the preceding paragraphs. Preferably, an algorithm or irradiation plan 1960 is used as an input to the intensity controller 1940, which controls the RF field modulation by directing the RF signal in the betatron oscillation generation in the RF cavity system 1910. The irradiation plan 1960 preferably includes the desired intensity of the charged particle beam as a function of time, energy of the charged particle beam as a function of time, for each patient rotation position, and/or for each x-, y-position of the charged particle beam. In yet another example, when a current from material 130 resulting from protons passing through or hitting material is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In still yet another embodiment, intensity modulation of the extracted proton beam is controlled by the main controller 110. The main controller 110 optionally and/or additionally controls timing of extraction of the charged particle beam and energy of the extracted proton beam. The benefits of the system include a multi-dimensional scanning system. Particularly, the system allows independence in: (1) energy of the protons extracted and (2) intensity of the protons extracted. That is, energy of the protons extracted is controlled by an energy control system and an intensity control system controls the intensity of the extracted protons. The energy control system and intensity control system are optionally independently controlled. Preferably, the main controller 110 controls the energy control system and the main controller 110 simultaneously controls the intensity control system to yield an extracted proton beam with controlled energy and controlled intensity where the controlled energy and controlled intensity are independently variable. Thus the irradiation spot hitting the tumor is under independent control of: time; energy; intensity; x-axis position, where the x-axis represents horizontal movement of the proton beam relative to the patient, and y-axis position, where the y-axis represents vertical movement of the proton beam relative to the patient.In addition, the patient is optionally independently translated and/or rotated relative to a translational axis of the proton beam at the same time. Referring now to FIG. 20A and FIG. 20B, a proton beam position verification system 2000 is described. A nozzle 2010 provides an outlet for the second reduced pressure vacuum system initiating at the foil 395 of the tandem accelerator 390 and running through the synchrotron 130 to a nozzle foil 2020 covering the end of the nozzle 2010. The nozzle expands in x-, y-cross-sectional area along the z-axis of the proton beam path 268 to allow the proton beam 268 to be scanned along the x- and y-axes by the vertical control element 142 and horizontal control element 144, respectively. The nozzle foil 2020 is preferably mechanically supported by the outer edges of an exit port of the nozzle 2010. An example of a nozzle foil 2020 is a sheet of about 0.1 inch thick aluminum foil. Generally, the nozzle foil separates atmosphere pressures on the patient side of the nozzle foil 2020 from the low pressure region, such as about 10−5 to 10−7 torr region, on the synchrotron 130 side of the nozzle foil 2020. The low pressure region is maintained to reduce scattering of the proton beam 264, 268. Still referring to FIG. 20A and FIG. 20B, the proton beam verification system 2000 is a system that allows for monitoring of the actual proton beam position 268, 269 in real-time without destruction of the proton beam. The proton beam verification system 2000 preferably includes a proton beam position verification layer 2030, which is also referred to herein as a coating, luminescent, fluorescent, phosphorescent, radiance, or viewing layer. The verification layer or coating layer 2030 is preferably a coating or thin layer substantially in contact with an inside surface of the nozzle foil 2020, where the inside surface is on the synchrotron side of the nozzle foil 2020. Less preferably, the verification layer or coating layer 2030 is substantially in contact with an outer surface of the nozzle foil 2020, where the outer surface is on the patient treatment side of the nozzle foil 2020. Preferably, the nozzle foil 2020 provides a substrate surface for coating by the coating layer. Optionally, a binding layer is located between the coating layer 2030 and the nozzle foil 2020. Optionally a separate coating layer support element, on which the coating 2030 is mounted, is placed anywhere in the proton beam path 268. Referring now to FIG. 20B, the coating 2030 yields a measurable spectroscopic response, spatially viewable by the detector 2040, as a result of transmission by the proton beam 268. The coating 2030 is preferably a phosphor, but is optionally any material that is viewable or imaged by a detector where the material changes spectroscopically as a result of the proton beam path 268 hitting or transmitting through the coating 2030. A detector or camera 2040 views the coating layer 2030 and determines the current position of the proton beam 269 by the spectroscopic differences resulting from protons passing through the coating layer. For example, the camera 2040 views the coating surface 2030 as the proton beam 268 is being scanned by the horizontal 144 and vertical 142 beam position control elements during treatment of the tumor 2120. The camera 2040 views the current position of the proton beam 269 as measured by spectroscopic response. The coating layer 2030 is preferably a phosphor or luminescent material that glows or emits photons for a short period of time, such as less than 5 seconds for a 50% intensity, as a result of excitation by the proton beam 268. Optionally, a plurality of cameras or detectors 2040 are used, where each detector views all or a portion of the coating layer 2030. For example, two detectors 2040 are used where a first detector views a first half of the coating layer and the second detector views a second half of the coating layer. Preferably, at least a portion of the detector 2040 is mounted into the nozzle 2010 to view the proton beam position after passing through the first axis and second axis controllers 142, 144. Preferably, the coating layer 2030 is positioned in the proton beam path 268 in a position prior to the protons striking the patient 2130. Still referring to FIG. 20B, the main controller 130, connected to the camera or detector 2040 output, compares the actual proton beam position 269 with the planned proton beam position and/or a calibration reference to determine if the actual proton beam position 269 is within tolerance. The proton beam verification system 2000 preferably is used in at least two phases, a calibration phase and a proton beam treatment phase. The calibration phase is used to correlate, as a function of x-, y-position of the glowing response the actual x-, y-position of the proton beam at the patient interface. During the proton beam treatment phase, the proton beam position is monitored and compared to the calibration and/or treatment plan to verify accurate proton delivery to the tumor 2120 and/or as a proton beam shutoff safety indicator. Patient Positioning Referring now to FIG. 21A and FIG. 21B, the patient is preferably positioned on or within a patient translation and rotation positioning system 2110 of the patient interface module 150. The patient translation and rotation positioning system 2110 is used to translate the patient and/or rotate the patient into a zone where the proton beam can scan the tumor using a scanning system 140 or proton targeting system, described infra. Essentially, the patient positioning system 2110 performs large movements of the patient to place the tumor near the center of a proton beam path 268 and the proton scanning or targeting system 140 performs fine movements of the momentary beam position 269 in targeting the tumor 2120. To illustrate, FIG. 21A shows the momentary proton beam position 269 and a range of scannable positions 2140 using the proton scanning or targeting system 140, where the scannable positions 2140 are about the tumor 2120 of the patient 2130. In this example, the scannable positions are scanned along the x- and y-axes; however, scanning is optionally simultaneously performed along the z-axis as described infra. This illustratively shows that the y-axis movement of the patient occurs on a scale of the body, such as adjustment of about 1, 2, 3, or 4 feet, while the scannable region of the proton beam 268 covers a portion of the body, such as a region of about 1, 2, 4, 6, 8, 10, or 12 inches. The patient positioning system and its rotation and/or translation of the patient combines with the proton targeting system to yield precise and/or accurate delivery of the protons to the tumor. Referring still to FIG. 21A and FIG. 21B, the patient positioning system 2110 optionally includes a bottom unit 2112 and a top unit 2114, such as discs or a platform. Referring now to FIG. 21A, the patient positioning unit 2110 is preferably y-axis adjustable 2116 to allow vertical shifting of the patient relative to the proton therapy beam 268. Preferably, the vertical motion of the patient positioning unit 2110 is about 10, 20, 30, or 50 centimeters per minute. Referring now to FIG. 21B, the patient positioning unit 2110 is also preferably rotatable 2117 about a rotation axis, such as about the y-axis running through the center of the bottom unit 2112 or about a y-axis running through the tumor 2120, to allow rotational control and positioning of the patient relative to the proton beam path 268. Preferably the rotational motion of the patient positioning unit 2110 is about 360 degrees per minute. Optionally, the patient positioning unit rotates about 45, 90, or 180 degrees. Optionally, the patient positioning unit 2110 rotates at a rate of about 45, 90, 180, 360, 720, or 1080 degrees per minute. The rotation of the positioning unit 2117 is illustrated about the rotation axis at two distinct times, t1 and t2. Protons are optionally delivered to the tumor 2120 at n times where each of the n times represent a different relative direction of the incident proton beam 269 hitting the patient 2130 due to rotation of the patient 2117 about the rotation axis. Any of the semi-vertical, sitting, or laying patient positioning embodiments described, infra, are optionally vertically translatable along the y-axis or rotatable about the rotation or y-axis. Preferably, the top and bottom units 2112, 2114 move together, such that they rotate at the same rates and translate in position at the same rates. Optionally, the top and bottom units 2112, 2114 are independently adjustable along the y-axis to allow a difference in distance between the top and bottom units 2112, 2114. Motors, power supplies, and mechanical assemblies for moving the top and bottom units 2112, 2114 are preferably located out of the proton beam path 269, such as below the bottom unit 2112 and/or above the top unit 2114. This is preferable as the patient positioning unit 2110 is preferably rotatable about 360 degrees and the motors, power supplies, and mechanical assemblies interfere with the protons if positioned in the proton beam path 269 Proton Delivery Efficiency Referring now to FIG. 22A, a common distribution of relative doses for both X-rays and proton irradiation is presented. As shown, X-rays deposit their highest dose near the surface of the targeted tissue and then deposited doses exponentially decrease as a function of tissue depth. The deposition of X-ray energy near the surface is non-ideal for tumors located deep within the body, which is usually the case, as excessive damage is done to the soft tissue layers surrounding the tumor 2120. The advantage of protons is that they deposit most of their energy near the end of the flight trajectory as the energy loss per unit path of the absorber transversed by a proton increases with decreasing particle velocity, giving rise to a sharp maximum in ionization near the end of the range, referred to herein as the Bragg peak. Furthermore, since the flight trajectory of the protons is variable by increasing or decreasing the initial kinetic energy or initial velocity of the proton, then the peak corresponding to maximum energy is movable within the tissue. Thus z-axis control of the proton depth of penetration is allowed by the acceleration/extraction process, described supra. As a result of proton dose-distribution characteristics, using the algorithm described, infra, a radiation oncologist can optimize dosage to the tumor 2120 while minimizing dosage to surrounding normal tissues. Herein, the term ingress refers to a place charged particles enter into the patient 2130 or a place of charged particles entering the tumor 2120. The ingress region of the Bragg energy profile refers to the relatively flat dose delivery portion at shallow depths of the Bragg energy profile. Similarly, herein the terms proximal or the clause proximal region refer to the shallow depth region of the tissue that receives the relatively flat radiation dose delivery portion of the delivered Bragg profile energy. Herein, the term distal refers to the back portion of the tumor located furthest away from the point of origin where the charged particles enter the tumor. In terms of the Bragg energy profile, the Bragg peak is at the distal point of the profile. Herein, the term ventral refers to the front of the patient and the term dorsal refers to the back of the patient. As an example of use, when delivering protons to a tumor in the body, the protons ingress through the healthy tissue and if delivered to the far side of the tumor, the Bragg peak occurs at the distal side of the tumor. For a case where the proton energy is not sufficient to reach the far side of the tumor, the distal point of the Bragg energy profile is the region of furthest penetration into the tumor. The Bragg peak energy profile shows that protons deliver their energy across the entire length of the body penetrated by the proton up to a maximum penetration depth. As a result, energy is being delivered, in the proximal portion of the Bragg peak energy profile, to healthy tissue, bone, and other body constituents before the proton beam hits the tumor. It follows that the shorter the pathlength in the body prior to the tumor, the higher the efficiency of proton delivery efficiency, where proton delivery efficiency is a measure of how much energy is delivered to the tumor relative to healthy portions of the patient. Examples of proton delivery efficiency include: (1) a ratio of proton energy delivered to the tumor over proton energy delivered to non-tumor tissue; (2) pathlength of protons in the tumor versus pathlength in the non-tumor tissue; and/or (3) damage to a tumor compared to damage to healthy body parts. Any of these measures are optionally weighted by damage to sensitive tissue, such as a nervous system element, heart, brain, or other organ. To illustrate, for a patient in a laying position where the patient is rotated about the y-axis during treatment, a tumor near the heart would at times be treated with protons running through the head-to-heart path, leg-to-heart path, or hip-to-heart path, which are all inefficient compared to a patient in a sitting or semi-vertical position where the protons are all delivered through a shorter chest-to-heart; side-of-body-to-heart, or back-to-heart path. Particularly, compared to a laying position, using a sitting or semi-vertical position of the patient, a shorter pathlength through the body to a tumor is provided to a tumor located in the torso or head, which results in a higher or better proton delivery efficiency. Herein proton delivery efficiency is separately described from time efficiency or synchrotron use efficiency, which is a fraction of time that the charged particle beam apparatus is in a tumor treating operation mode. Beam Energy Referring now to FIG. 22B, a method and apparatus for calculating beam energy of a beam extracted from the synchrotron 130 is described, where beam energy refers to a speed and/or a velocity of the charged particle beam. The synchrotron 130 has a circulating beam path 264, which has a circulation pathlength, b. The circulation pathlength is the charged particle beam pathlength of one orbit about the center 280 of the synchrotron. To induce the betatron oscillation, described supra, the radio-frequency field of the RF cavity system 1910 has a peak-to-peak interval time period that is: equal to the time or an integer multiple of the time, that the circulating charged particles takes to complete one circuit in the circulation beam path 264 having pathlength b. Alternatively, the time that the circulating charged particle takes to complete one circuit in the circulation beam path 264 having pathlength b is an integer multiple, such as 2, 3, 4, 5, or more, of the peak-to-peak interval time period of the radio-frequency applied in the RF cavity system 1910. As the beam is accelerated/decelerated, the time for the charged particles to complete one circuit of pathlength b decreases/increases and the peak-to-peak interval time period is reduced/increased so that the RF cavity system 1910 applies the above described RF field across the first blade 1912 and the second blade 1914 in phase with a grouping, referred to as a bunch, of the charged particles traversing the RF cavity system 1910. In any of the three cases, at the moment of extraction, the pathlength, b, is known and the peak-to-peak interval time period of the RF-field is known. As pathlength and time to move the charged particles along the pathlength is known, the speed or velocity of the charged particle beam, which relates to the energy of the charged particle beam, is readily calculated such as velocity being proportional and/or equal to distance per unit time. This initial energy is referred to herein as the pre-extraction energy. As described, supra, energy is lost upon the charged particle beam in the altered circulating beam path 265 traversing the extraction material 1930. Referring now to FIG. 22C, the amount of energy lost is dependent upon a thickness and/or density of the extraction material 1930, where the lost energy is: (1) determined via calculation and/or (2) is determined via measurement or empirical epistemology. Hence, the energy of the extracted beam is calculable from the pre-extraction energy, derived from the RF-field period and the circulation pathlength, b, less the energy lost when the charged particle beam traverses through the extraction material. Referring again to FIG. 22A, since the energy of the charged particle beam determines a depth of discharge of energy in the patient, knowledge of the actual energy of the extracted beam from metrics is critical in terms of tumor targeting and/or safety. Here, the energy of the charged particle beam is known with very small uncertainties, such as the known and constant pathlength, b, the extremely accurate and precise RF-field time period, and a controlled, testable, and calculable pathlength and density of the extraction material. In stark contrast, other methods of determining beam energy have many stackable errors, such as: (1) use non-uniform materials to slow the beam with resultant errors in pathlength, (2), rely on detectors for determining position of an energy discharge, with inherent errors inherent in spatial optics, and/or (3) occur on a beam at a specific time period not used to treat the tumor, specifically, the beam measured is not the beam used for treatment as the beam for treatment occurs at a separate time and/or even a distinctly different energy from that measured. Referring again to FIGS. 22(A-C) and FIG. 1, using the above described system of determining energy of the extracted charged particle beam, the main controller 110 of the charged particle cancer therapy system 100 controls the accelerator system 132 and the extraction system 134 of the synchrotron 130 in coordination with a charged particle cancer therapy treatment plan to deliver accurate and precise bunches of charged particles to the tumor 2120 of the patient 2130 in the multi-axes/multi-field cancer treatment system described herein. Depth Targeting Referring now to FIGS. 23(A-E), x-axis scanning of the proton beam is illustrated while z-axis energy of the proton beam undergoes controlled variation 2300 to allow irradiation of slices of the tumor 2120. For clarity of presentation, the simultaneous y-axis scanning that is performed is not illustrated. In FIG. 23A, irradiation is commencing with the momentary proton beam position 269 at the start of a first slice. Referring now to FIG. 23B, the momentary proton beam position is at the end of the first slice. Importantly, during a given slice of irradiation, the proton beam energy is preferably continuously controlled and changed according to the tissue mass and density in front of the tumor 2120. The variation of the proton beam energy to account for tissue density thus allows the beam stopping point, or Bragg peak, to remain inside the tissue slice. The variation of the proton beam energy during scanning or during x-, y-axes scanning is possible due to the acceleration/extraction techniques, described supra, which allow for acceleration of the proton beam during extraction. FIG. 23C, FIG. 23D, and FIG. 23E show the momentary proton beam position in the middle of the second slice, two-thirds of the way through a third slice, and after finalizing irradiation from a given direction, respectively. Using this approach, controlled, accurate, and precise delivery of proton irradiation energy to the tumor 2120, to a designated tumor subsection, or to a tumor layer is achieved. Efficiency of deposition of proton energy to tumor, as defined as the ratio of the proton irradiation energy delivered to the tumor relative to the proton irradiation energy delivered to the healthy tissue is further described infra. Multi-Field Irradiation It is desirable to maximize efficiency of deposition of protons to the tumor 2120, as defined by maximizing the ratio of the proton irradiation energy delivered to the tumor 2120 relative to the proton irradiation energy delivered to the healthy tissue. Irradiation from one, two, or three directions into the body, such as by rotating the body about 90 degrees between irradiation sub-sessions results in proton irradiation from the proximal portion of the Bragg peak concentrating into one, two, or three healthy tissue volumes, respectively. It is desirable to further distribute the proximal portion of the Bragg peak energy evenly through the healthy volume tissue surrounding the tumor 2120. Multi-field irradiation is proton beam irradiation from a plurality of entry points into the body. For example, the patient 2130 is rotated and the radiation source point is held constant. For example, the patient 2130 is rotated through 360 degrees and proton therapy is applied from a multitude of angles resulting in the ingress or proximal radiation being circumferentially spread about the tumor yielding enhanced proton irradiation efficiency. In one case, the body is rotated into greater than 3, 5, 10, 15, 20, 25, 30, or 35 positions and proton irradiation occurs with each rotation position. Rotation of the patient is preferably performed using the patient positioning system 2110 and/or the bottom unit 2112 or disc, described supra. Rotation of the patient 2130 while keeping the delivery proton beam 268 in a relatively fixed orientation allows irradiation of the tumor 2120 from multiple directions without use of a new collimator for each direction. Further, as no new setup is required for each rotation position of the patient 2130, the system allows the tumor 2120 to be treated from multiple directions without reseating or positioning the patient, thereby minimizing tumor 2120 regeneration time, increasing the synchrotrons efficiency, and increasing patient throughput. The patient is optionally centered on the bottom unit 2112 or the tumor 2120 is optionally centered on the bottom unit 2112. If the patient is centered on the bottom unit 2112, then the first axis control element 142 and second axis control element 144 are programmed to compensate for the off central axis of rotation position variation of the tumor 2120. Referring now to FIGS. 24(A-E), an example of multi-field irradiation 2400 is presented. In this example, five patient rotation positions are illustrated; however, the five rotation positions are discrete rotation positions of about thirty-six rotation positions, where the body is rotated about ten degrees with each position. Referring now to FIG. 24A, a range of irradiation beam positions 269 is illustrated from a first body rotation position, illustrated as the patient 2130 facing the proton irradiation beam where the tumor receives the bulk of the Bragg profile energy while a first healthy volume 2411 is irradiated by the less intense ingress portion of the Bragg profile energy. Referring now to FIG. 24B, the patient 2130 is rotated about forty degrees and the irradiation is repeated. In the second position, the tumor 2120 again receives the bulk of the irradiation energy and a second healthy tissue volume 2412 receives the smaller ingress portion of the Bragg profile energy. Referring now to FIG. 24C, FIG. 24D, and FIG. 24E, the patient 2130 is rotated a total of about 90, 130, and 180 degrees, respectively. For each of the third, fourth, and fifth rotation positions, the tumor 2120 receives the bulk of the irradiation energy and the third, fourth, and fifth healthy tissue volumes 2413, 2414, 1415 receive the smaller ingress portion of the Bragg peak energy, respectively. Thus, the rotation of the patient during proton therapy results in the proximal or ingress energy of the delivered proton energy to be distributed about the tumor 2120, such as to regions one to five 2411-2415, while along a given axis, at least about 75, 80, 85, 90, or 95 percent of the energy is delivered to the tumor 2120. For a given rotation position, all or part of the tumor is irradiated. For example, in one embodiment only a distal section or distal slice of the tumor 2120 is irradiated with each rotation position, where the distal section is a section furthest from the entry point of the proton beam into the patient 2130. For example, the distal section is the dorsal side of the tumor when the patient 2130 is facing the proton beam and the distal section is the ventral side of the tumor when the patient 2130 is facing away from the proton beam. Referring now to FIG. 25, a second example of multi-field irradiation 2500 is presented where the proton source is stationary and the patient 2130 is rotated. For ease of presentation, the stationary but scanning proton beam path 269 is illustrated as entering the patient 2130 from varying sides at times t1, t2, t3, . . . , tn, tn+1 as the patient is rotated. At a first time, t1, the ingress side or proximal region of the Bragg peak profile hits a first area, A1. Again, the proximal end of the Bragg peak profile refers to the relatively shallow depths of tissue where Bragg energy profile energy delivery is relatively flat. The patient is rotated and the proton beam path is illustrated at a second time, t2, where the ingress energy of the Bragg energy profile hits a second area, A2. Thus, the low radiation dosage of the ingress region of the Bragg profile energy is delivered to the second area. At a third time, the ingress end of the Bragg energy profile hits a third area, A3. This rotation and irradiation process is repeated n times, where n is a positive number greater than five and preferably greater than about 10, 20, 30, 100, or 300. As illustrated, at an nth time, tn, if the patient 2130 is rotated further, the scanning proton beam 269 would hit a sensitive body constituent 2150, such as the spinal cord or eyes. Irradiation is preferably suspended until the sensitive body constituent is rotated out of the scanning proton beam 269 path. Irradiation is resumed at a time, tn+1, after the sensitive body constituent 2150 is rotated out of the proton beam path. In this manner: the distal Bragg peak energy is always within the tumor; the radiation dose delivery of the distal region of the Bragg energy profile is spread over the tumor; the ingress or proximal region of the Bragg energy profile is distributed in healthy tissue about the tumor 2120; and sensitive body constituents 2150 receive minimal or no proton beam irradiation. Proton Delivery Efficiency Herein, charged particle or proton delivery efficiency is radiation dose delivered to the tumor compared to radiation dose delivered to the healthy regions of the patient. A proton delivery enhancement method is described where proton delivery efficiency is enhanced, optimized, or maximized. In general, multi-field irradiation is used to deliver protons to the tumor from a multitude of rotational directions. From each direction, the energy of the protons is adjusted to target the distal portion of the tumor, where the distal portion of the tumor is the volume of the tumor furthest from the entry point of the proton beam into the body. For clarity, the process is described using an example where the outer edges of the tumor are initially irradiated using distally applied radiation through a multitude of rotational positions, such as through 360 degrees. This results in a symbolic or calculated remaining smaller tumor for irradiation. The process is then repeated as many times as necessary on the smaller tumor. However, the presentation is for clarity. In actuality, irradiation from a given rotational angle is performed once with z-axis proton beam energy and intensity being adjusted for the calculated smaller inner tumors during x- and y-axis scanning. Referring now to FIG. 26A and FIG. 26B, the proton delivery enhancement method is further described. Referring now to FIG. 26A, at a first point in time protons are delivered to the tumor 2120 of the patient 2130 from a first direction. From the first rotational direction, the proton beam is scanned 269 across the tumor. As the proton beam is scanned across the tumor the energy of the proton beam is adjusted to allow the Bragg peak energy to target the distal portion of the tumor. Again, distal refers to the back portion of the tumor located furthest away from where the charged particles enter the tumor. As illustrated, the proton beam is scanned along an x-axis across the patient. This process allows the Bragg peak energy to fall within the tumor, for the middle area of the Bragg peak profile to fall in the middle and proximal portion of the tumor, and for the small intensity ingress portion of the Bragg peak to hit healthy tissue. In this manner, the maximum radiation dose is delivered to the tumor or the proton dose efficiency is maximized for the first rotational direction. After irradiation from the first rotational position, the patient is rotated to a new rotational position. Referring now to FIG. 26B, the scanning of the proton beam is repeated. Again, the distal portion of the tumor is targeted with adjustment of the proton beam energy to target the Bragg peak energy to the distal portion of the tumor. Naturally, the distal portion of the tumor for the second rotational position is different from the distal portion of the tumor for the first rotational position. Referring now to FIG. 26C, the process of rotating the patient and then irradiating the new distal portion of the tumor is further illustrated at an nth rotational position. Preferably, the process of rotating the patient and scanning along the x- and y-axes with the Z-axes energy targeting the new distal portion of the tumor is repeated, such as with more than 5, 10, 20, or 30 rotational positions or with about 36 rotational positions. For clarity, FIGS. 26(A-C) and FIG. 26 E show the proton beam as having moved, but in actuality, the proton beam is stationary and the patient is rotated, such as via use of rotating the bottom unit 2112 of the patient positioning system 2110. Also, FIGS. 26(A-C) and FIG. 26E show the proton beam being scanned across the tumor along the x-axis. Though not illustrated for clarity, the proton beam is additionally scanned up and down the tumor along the y-axis of the patient. Combined, the distal portion or volume of the tumor is irradiated along the x- and y-axes with adjustment of the z-axis energy level of the proton beam. In one case, the tumor is scanned along the x-axis and the scanning is repeated along the x-axis for multiple y-axis positions. In another case, the tumor is scanned along the y-axis and the scanning is repeated along the y-axis for multiple x-axis positions. In yet another case, the tumor is scanned by simultaneously adjusting the x- and y-axes so that the distal portion of the tumor is targeted. In all of these cases, the z-axis or energy of the proton beam is adjusted along the contour of the distal portion of the tumor to target the Bragg peak energy to the distal portion of the tumor. Referring now to FIG. 26D, after targeting the distal portion of the tumor from multiple directions, such as through 360 degrees, the outer perimeter of the tumor has been strongly irradiated with peak Bragg profile energy, the middle of the Bragg peak energy profile energy has been delivered along an inner edge of the heavily irradiated tumor perimeter, and smaller dosages from the ingress portion of the Bragg energy profile are distributed throughout the tumor and into some healthy tissue. The delivered dosages or accumulated radiation flux levels are illustrated in a cross-sectional area of the tumor 2120 using an iso-line plot. After a first full rotation of the patient, symbolically, the darkest regions of the tumor are nearly fully irradiated and the regions of the tissue having received less radiation are illustrated with a gray scale with the whitest portions having the lowest radiation dose. Referring now to FIG. 26E, after completing the distal targeting multi-field irradiation, a smaller inner tumor is defined, where the inner tumor is already partially irradiated. The smaller inner tumor is indicated by the dashed line 2630. The above process of irradiating the tumor is repeated for the newly defined smaller tumor. The proton dosages to the outer or distal portions of the smaller tumor are adjusted to account for the dosages delivered from other rotational positions. After the second tumor is irradiated, a yet smaller third tumor is defined. The process is repeated until the entire tumor is irradiated at the prescribed or defined dosage. As described at the onset of this example, the patient is preferably only rotated to each rotational position once. In the above described example, after irradiation of the outer perimeter of the tumor, the patient is rotationally positioned, such as through 360 degrees, and the distal portion of the newest smaller tumor is targeted as described, supra. However, the irradiation dosage to be delivered to the second smaller tumor and each subsequently smaller tumor is known a-priori. Hence, when at a given angle of rotation, the smaller tumor or multiple progressively smaller tumors, are optionally targeted so that the patient is only rotated to the multiple rotational irradiation positions once. The goal is to deliver a treatment dosage to each position of the tumor, to preferably not exceed the treatment dosage to any position of the tumor, to minimize ingress radiation dosage to healthy tissue, to circumferentially distribute ingress radiation hitting the healthy tissue, and to further minimize ingress radiation dosage to sensitive areas. Since the Bragg energy profile is known, it is possible to calculated the optimal intensity and energy of the proton beam for each rotational position and for each x- and y-axis scanning position. These calculation result in slightly less than threshold radiation dosage to be delivered to the distal portion of the tumor for each rotational position as the ingress dose energy from other positions bring the total dose energy for the targeted position up to the threshold delivery dose. Referring again to FIG. 26A and FIG. 26C, the intensity of the proton beam is preferably adjusted to account for the cross-sectional distance or density of the healthy tissue. An example is used for clarity. Referring now to FIG. 26A, when irradiating from the first position where the healthy tissue has a small area 2610, the intensity of the proton beam is preferably increased as relatively less energy is delivered by the ingress portion of the Bragg profile to the healthy tissue. Referring now to FIG. 26C, in contrast when irradiating from the nth rotational position where the healthy tissue has a large cross-sectional area 2620, the intensity of the proton beam is preferably decreased as a greater fraction the proton dose is delivered to the healthy tissue from this orientation. In one example, for each rotational position and/or for each z-axis distance into the tumor, the efficiency of proton dose delivery to the tumor is calculated. The intensity of the proton beam is made proportional to the calculated efficiency. Essentially, when the scanning direction has really good efficiency, the intensity is increased and vise-versa. For example, if the tumor is elongated, generally the efficiency of irradiating the distal portion by going through the length of the tumor is higher than irradiating a distal region of the tumor by going across the tumor with the Bragg energy distribution. Generally, in the optimization algorithm: distal portions of the tumor are targeted for each rotational position; the intensity of the proton beam is largest with the largest cross-sectional area of the tumor; intensity is larger when the intervening healthy tissue volume is smallest; and intensity is minimized or cut to zero when the intervening healthy tissue volume includes sensitive tissue, such as the spinal cord or eyes. Using an algorithm so defined, the efficiency of radiation dose delivery to the tumor is maximized. More particularly, the ratio of radiation dose delivered to the tumor versus the radiation dose delivered to surrounding healthy tissue approaches a maximum. Further, integrated radiation dose delivery to each x, y, and z-axis volume of the tumor as a result of irradiation from multiple rotation directions is at or near the preferred dose level. Still further, ingress radiation dose delivery to healthy tissue is circumferentially distributed about the tumor via use of multi-field irradiation where radiation is delivered from a plurality of directions into the body, such as more than 5, 10, 20, or 30 directions. Multi-Field Irradiation In one multi-field irradiation example, the particle therapy system with a synchrotron ring diameter of less than six meters includes ability to: rotate the patient through about 360 degrees; extract radiation in about 0.1 to 10 seconds; scan vertically about 100 millimeters; scan horizontally about 700 millimeters; vary beam energy from about 30 to 330 MeV/second during irradiation; vary the proton beam intensity independently of varying the proton beam energy; focus the proton beam with a cross-sectional distance from about 2 to 20 millimeters at the tumor; and/or complete multi-field irradiation of a tumor in less than about 1, 2, 4, or 6 minutes as measured from the time of initiating proton delivery to the patient 2130. Two multi-field irradiation methods are described. In the first method, the main controller 110 rotationally positions the patient 2130 and subsequently irradiates the tumor 2120. The process is repeated until a multi-field irradiation plan is complete. In the second method, the main controller 110 simultaneously rotates and irradiates the tumor 2120 within the patient 2130 until the multi-field irradiation plan is complete. More particularly, the proton beam irradiation occurs while the patient 2130 is being rotated. The 3-dimensional scanning system of the proton spot focal point, described herein, is preferably combined with a rotation/raster method. The method includes layer wise tumor irradiation from many directions. During a given irradiation slice, the proton beam energy is continuously changed according to the tissue's density in front of the tumor to result in the beam stopping point, defined by the Bragg peak, always being inside the tumor and inside the irradiated slice. The novel method allows for irradiation from many directions, referred to herein as multi-field irradiation, to achieve the maximal effective dose at the tumor level while simultaneously significantly reducing possible side-effects on the surrounding healthy tissues in comparison to existing methods. Essentially, the multi-field irradiation system distributes dose-distribution at tissue depths not yet reaching the tumor. Proton Beam Position Control Referring now to FIG. 27A and FIG. 27B, a beam delivery and tissue volume scanning system is illustrated. Presently, the worldwide radiotherapy community uses a method of dose field forming using a pencil beam scanning system. In stark contrast, FIG. 27A and FIG. 27B illustrate a spot scanning system or tissue volume scanning system. In the tissue volume scanning system, the proton beam is controlled, in terms of transportation and distribution, using an inexpensive and precise scanning system. The scanning system is an active system, where the beam is focused into a spot focal point of about one-half, one, two, or three millimeters in diameter. The focal point is translated along two axes while simultaneously altering the applied energy of the proton beam, which effectively changes the third dimension of the focal point. The system is applicable in combination with the above described rotation of the body, which preferably occurs in-between individual moments or cycles of proton delivery to the tumor. Optionally, the rotation of the body by the above described system occurs continuously and simultaneously with proton delivery to the tumor. For example, in the illustrated system in FIG. 27A, the spot is translated horizontally, is moved down a vertical y-axis, and is then back along the horizontal axis. In this example, current is used to control a vertical scanning system having at least one magnet. The applied current alters the magnetic field of the vertical scanning system to control the vertical deflection of the proton beam. Similarly, a horizontal scanning magnet system controls the horizontal deflection of the proton beam. The degree of transport along each axes is controlled to conform to the tumor cross-section at the given depth. The depth is controlled by changing the energy of the proton beam. For example, the proton beam energy is decreased, so as to define a new penetration depth, and the scanning process is repeated along the horizontal and vertical axes covering a new cross-sectional area of the tumor. Combined, the three axes of control allow scanning or movement of the proton beam focal point over the entire volume of the cancerous tumor. The time at each spot and the direction into the body for each spot is controlled to yield the desired radiation does at each sub-volume of the cancerous volume while distributing energy hitting outside of the tumor. The focused beam spot volume dimension is preferably tightly controlled to a diameter of about 0.5, 1, or 2 millimeters, but is alternatively several centimeters in diameter. Preferred design controls allow scanning in two directions with: (1) a vertical amplitude of about 100 mm amplitude and frequency up to about 200 Hz; and (2) a horizontal amplitude of about 700 mm amplitude and frequency up to about 1 Hz. Proton Beam Energy Control In FIG. 27A, the proton beam is illustrated along a z-axis controlled by the beam energy, the horizontal movement is along an x-axis, and the vertical direction is along a y-axis. The distance the protons move along the z-axis into the tissue, in this example, is controlled by the kinetic energy of the proton. This coordinate system is arbitrary and exemplary. Referring now to FIG. 27B, preferably control of the proton beam is controlled in 3-dimensional space using two scanning magnet systems and by simultaneously varying and controlling the kinetic energy of the proton beam. The use of the extraction system, described supra, allows for different scanning patterns. Particularly, the system allows simultaneous adjustment of the x-, y-, and z-axes in the irradiation of the solid tumor. Stated again, instead of scanning along an x,y-plane and then adjusting energy of the protons, such as with a range modulation wheel, the system allows for moving along the z-axes while simultaneously adjusting the x- and or y-axes. Hence, rather than irradiating slices of the tumor, the tumor is optionally irradiated in three simultaneous dimensions. For example, the tumor is irradiated around an outer edge of the tumor in three dimensions. Then the tumor is irradiated around an outer edge of an internal section of the tumor. This process is repeated until the entire tumor is irradiated. The outer edge irradiation is preferably coupled with simultaneous rotation of the subject, such as about a vertical y-axis. This system allows for maximum efficiency of deposition of protons to the tumor, as defined as the ratio of the proton irradiation energy delivered to the tumor relative to the proton irradiation energy delivered to the healthy tissue. Combined, the system allows for multi-axes control of the charged particle beam system in a small space with a low or small power supply. For example, the system uses multiple magnets where each magnet has at least one edge focusing effect in each turning section of the synchrotron and/or multiple magnets having concentrating magnetic field geometry, as described supra. The multiple edge focusing effects in the circulating beam path of the synchrotron combined with the concentration geometry of the magnets and described extraction system yields a synchrotron having: a small circumference system, such as less than about 50 meters; a vertical proton beam size gap of about 2 cm; corresponding reduced power supply requirements associated with the reduced gap size; an extraction system not requiring a newly introduced magnetic field; acceleration or deceleration of the protons during extraction; and control of z-axis energy during extraction.The result is a 3-dimensional scanning system, x-, y-, and z-axes control, where the z-axes control resides in the synchrotron and where the z-axes energy is variably controlled during the extraction process inside the synchrotron. Proton Beam Intensity Control Referring now to FIG. 28A and FIG. 28B, an intensity modulated 3-dimensional scanning system 2800 is described. Referring now to FIG. 28A, a proton beam is being scanned across and x- and/or y-axis as a function of time. With each time, the z-axis energy is optionally adjusted. In this case, from the first time, t1, to the third time, t3, the energy is increased, and from the third time, t3, to the fifth time, t5, the energy is decreased. Thus, the system is scanning in 3-dimensions along the x-, y-, and/or z-axes. Notably, the radiation energy delivery efficiency is increasing from t1 to t3 and decreasing from t3 to t5, where efficiency refers to the percentage of radiation delivered to the tumor. For example, at the third time, t3, the Bragg peak energy is located at the distal, or back, portion of the tumor located furthest away from the point of origin where the charged particles enter the tumor 2120. Delivered Bragg peak energy increases exponentially up to the maximum distance of proton energy penetration into the body. Hence, as illustrated the percentage of the delivered Bragg peak energy in the tumor is greatest at the third time period t3, which has the largest tumor cross-section pathlength, less at the second and fourth time periods, t2 and t4, and still less at the first and fifth time periods, t1 and t5, which have the smallest tumor cross-section pathlength Referring now to FIG. 28B, the intensity of the proton beam is also changing with time in a manner correlated with the radiation energy delivery efficiency. In this case, the intensity of the proton beam is greatest at the third time period t3, less at the second and fourth time periods, t2 and t4, and still less at the first and fifth time periods, t1 and t5. The intensity of the proton beam is adjusted to be more intense when radiation delivery efficiency increases using the proton beam extraction process 1800 and intensity control system 1900, described supra. Intensity is generally positively correlated with tumor cross-sectional pathlength, proton beam energy, and/or radiation delivery efficiency. Preferably, the distal portion of the tumor is targeted with each rotational position of the patient 2130 using the multi-field irradiation 2500, described supra, allowing repeated use of increased intensity at changing distal portions of the tumor 2120 as the patient 2130 is rotated in the multi-field irradiation system 2500. As an example, the intensity controller subsystem 1940 adjusts the radio-frequency field in the RF cavity system 1910 to yield an intensity to correlate with radiation delivery efficiency and/or with the irradiation plan 1960. Preferably, the intensity controller subsystem adjusts the intensity of the radiation beam using a reading of the actual intensity of the proton beam 1950 or from the feedback current from the extraction material 1930, which is proportional to the extracted beam intensity, as described supra. Thus, independent of the x- and y-axes targeting system and independent of the z-axis energy of the proton beam, the intensity of the proton beam is controlled, preferably in coordination with the multi-field irradiation system 2500, to yield peak intensities with greatest radiation delivery efficiency. The independent control of beam parameters allows use of a raster beam scanning system. Often, the greatest radiation delivery efficiency occurs, for a given rotational position of the patient, when the energy of the proton beam is largest. Hence, the intensity of the proton beam optionally correlates with the energy of the proton beam. The system is optionally timed with the patient's respiration cycle, as described infra. The system optionally operates in a raster beam scanning mode, as described infra. Proton Beam Position, Energy, and Intensity Control An example of a proton scanning or targeting system 140 used to direct the protons to the tumor with 4-dimensional scanning control is provided, where the 4-dimensional scanning control is along the x-, y-, and z-axes along with intensity control, as described supra. A fifth controllable axis is time. A sixth controllable axis is patient rotation. Typically, charged particles traveling along the transport path 268 are directed through a first axis control element 142, such as a vertical control, and a second axis control element 144, such as a horizontal control and into a tumor 2120. As described, supra, the extraction system also allows for simultaneous variation in the z-axis. Further, as described, supra, the intensity or dose of the extracted beam is optionally simultaneously and independently controlled and varied. Thus instead of irradiating a slice of the tumor, as in FIG. 27A, all four dimensions defining the targeting spot of the proton delivery in the tumor are simultaneously variable. The simultaneous variation of the proton delivery spot is illustrated in FIG. 27B by the spot delivery path 269 and in FIG. 28A, where the intensity is controlled as a function of efficiency of radiation delivery. In one example, the protons are initially directed around an outer edge of the tumor and are then directed around an inner radius of the tumor. Combined with rotation of the subject about a vertical axis, a multi-field irradiation process is used where a not yet irradiated portion of the tumor is preferably irradiated at the further distance of the tumor from the proton entry point into the body. This yields the greatest percentage of the proton delivery, as defined by the Bragg peak, into the tumor and minimizes damage to peripheral healthy tissue. Raster Scanning Raster beam scanning is optionally used. In traditional spot targeting systems, a spot of the tumor is targeted, then the radiation beam is turned off, a new spot is targeted, and the radiation beam is turned on. The cycle is repeated with changes in the x- and/or y-axis position. In stark contrast, in the raster beam scanning system, the proton beam is scanned from position to position in the tumor without turning off the radiation beam. In the raster scanning system, the irradiation is not necessarily turned off between spots, rather the irradiation of the tumor is optionally continuous as the beam scans between 3-dimensional locations in the tumor. The velocity of the scanning raster beam is optionally independently controlled. Velocity is change in the x, y, z position of the spot of the scanning beam with time. Hence, in a velocity control system, the rate of movement of the proton beam from coordinate to coordinate optionally varies with time or has a mathematical change in velocity with time. Stated again, the movement of the spot of the scanning beam with time is optionally not constant as a function of time. Further, the raster beam scanning system optionally uses the simultaneous and/or independent control of the x- and/or y-axes position, energy of the proton beam, intensity of the proton beam, and rotational position of the patient using the acceleration, extraction systems, and rotation systems, described supra. In one example, a charged particle beam system for irradiation of a tumor of a patient, includes: a synchrotron configured with an extraction foil, where a timing controller times the charged particle beam striking the extraction foil in an acceleration period in the synchrotron resulting in extraction of the charged particle beam at a selected energy and a raster beam scanning system configured to scan the charged particle beam across delivery positions while both (1) constantly delivering the charged particle beam at and between the delivery positions and (2) simultaneously varying the selected energy level of the charged particle beam across the delivery positions. Preferably, an intensity controller is used that is configured to measure a current resulting from the charged particle beam striking the extraction foil, the current used as a feedback control to a radio-frequency cavity system, wherein an applied radio frequency, using the feedback control, in the radio-frequency cavity system controls the number of particles in the charged particle beam striking the extraction foil resulting in intensity control of the charged particle beam. Preferably, a velocity controller is configured to change a rate of movement of the charged particle beam between the delivery position along x- and/or y-axes in the tumor as a function of time. Imaging/X-Ray System Herein, an X-ray system is used to illustrate an imaging system. Timing An X-ray is preferably collected either (1) just before or (2) concurrently with treating a subject with proton therapy for a couple of reasons. First, movement of the body, described supra, changes the local position of the tumor in the body relative to other body constituents. If the patient or subject 2130 has an X-ray taken and is then bodily moved to a proton treatment room, accurate alignment of the proton beam to the tumor is problematic. Alignment of the proton beam to the tumor 2120 using one or more X-rays is best performed at the time of proton delivery or in the seconds or minutes immediately prior to proton delivery and after the patient is placed into a therapeutic body position, which is typically a fixed position or partially immobilized position. Second, the X-ray taken after positioning the patient is used for verification of proton beam alignment to a targeted position, such as a tumor and/or internal organ position. Positioning An X-ray is preferably taken just before treating the subject to aid in patient positioning. For positioning purposes, an X-ray of a large body area is not needed. In one embodiment, an X-ray of only a local area is collected. When collecting an X-ray, the X-ray has an X-ray path. The proton beam has a proton beam path. Overlaying the X-ray path with the proton beam path is one method of aligning the proton beam to the tumor. However, this method involves putting the X-ray equipment into the proton beam path, taking the X-ray, and then moving the X-ray equipment out of the beam path. This process takes time. The elapsed time while the X-ray equipment moves has a couple of detrimental effects. First, during the time required to move the X-ray equipment, the body moves. The resulting movement decreases precision and/or accuracy of subsequent proton beam alignment to the tumor. Second, the time required to move the X-ray equipment is time that the proton beam therapy system is not in use, which decreases the total efficiency of the proton beam therapy system. X-Ray Source Lifetime Preferably, components in the particle beam therapy system require minimal or no maintenance over the lifetime of the particle beam therapy system. For example, it is desirable to equip the proton beam therapy system with an X-ray system having a long lifetime source, such as a lifetime of about 20 years. In one system, described infra, electrons are used to create X-rays. The electrons are generated at a cathode where the lifetime of the cathode is temperature dependent. Analogous to a light bulb, where the filament is kept in equilibrium, the cathode temperature is held in equilibrium at temperatures at about 200, 500, or 1000 degrees Celsius. Reduction of the cathode temperature results in increased lifetime of the cathode. Hence, the cathode used in generating the electrons is preferably held at as low of a temperature as possible. However, if the temperature of the cathode is reduced, then electron emissions also decrease. To overcome the need for more electrons at lower temperatures, a large cathode is used and the generated electrons are concentrated. The process is analogous to compressing electrons in an electron gun; however, here the compression techniques are adapted to apply to enhancing an X-ray tube lifetime. Referring now to FIG. 29, an example of an X-ray generation device 2900 having an enhanced lifetime is provided. Electrons 2920 are generated at a cathode 2910, focused with a control electrode 2912, and accelerated with a series of accelerating electrodes 2940. The accelerated electrons 2950 impact an X-ray generation source 2948 resulting in generated X-rays that are then directed along an X-ray path 3070 to the subject 2130. The concentrating of the electrons from a first diameter 2915 to a second diameter 2916 allows the cathode to operate at a reduced temperature and still yield the necessary amplified level of electrons at the X-ray generation source 2948. In one example, the X-ray generation source 2948 is the anode coupled with the cathode 2910 and/or the X-ray generation source is substantially composed of tungsten. Still referring to FIG. 29, a more detailed description of an exemplary X-ray generation device 2900 is described. An anode 2914/cathode 2910 pair is used to generated electrons. The electrons 2920 are generated at the cathode 2910 having a first diameter 2915, which is denoted d1. The control electrodes 2912 attract the generated electrons 2920. For example, if the cathode is held at about −150 kV and the control electrode is held at about −149 kV, then the generated electrons 2920 are attracted toward the control electrodes 2912 and focused. A series of accelerating electrodes 2940 are then used to accelerate the electrons into a substantially parallel path 2950 with a smaller diameter 2916, which is denoted d2. For example, with the cathode held at −150 kV, a first, second, third, and fourth accelerating electrodes 2942, 2944, 2946, 2948 are held at about −120, −90, −60, and −30 kV, respectively. If a thinner body part is to be analyzed, then the cathode 2910 is held at a smaller level, such as about −90 kV and the control electrode, first, second, third, and fourth electrode are each adjusted to lower levels. Generally, the voltage difference from the cathode to fourth electrode is less for a smaller negative voltage at the cathode and vise-versa. The accelerated electrons 2950 are optionally passed through a magnetic lens 2960 for adjustment of beam size, such as a cylindrical magnetic lens. The electrons are also optionally focused using quadrupole magnets 2970, which focus in one direction and defocus in another direction. The accelerated electrons 2950, which are now adjusted in beam size and focused strike the X-ray generation source 2948, such as tungsten, resulting in generated X-rays that pass through an optional blocker 3062 and proceed along an X-ray path 3070 to the subject. The X-ray generation source 2948 is optionally cooled with a cooling element 2949, such as water touching or thermally connected to a backside of the X-ray generation source 2948. The concentrating of the electrons from a first diameter 2915 to a second diameter 2916 allows the cathode to operate at a reduced temperature and still yield the necessary amplified level of electrons at the X-ray generation source 2948. More generally, the X-ray generation device 2900 produces electrons having initial vectors. One or more of the control electrode 2912, accelerating electrodes 2940, magnetic lens 2960, and quadrupole magnets 2970 combine to alter the initial electron vectors into parallel vectors with a decreased cross-sectional area having a substantially parallel path, referred to as the accelerated electrons 2950. The process allows the X-ray generation device 2900 to operate at a lower temperature. Particularly, instead of using a cathode that is the size of the electron beam needed, a larger electrode is used and the resulting electrons 2920 are focused and/or concentrated into the required electron beam needed. As lifetime is roughly an inverse of current density, the concentration of the current density results in a larger lifetime of the X-ray generation device. A specific example is provided for clarity. If the cathode has a fifteen mm radius or d1 is about 30 mm, then the area (π r2) is about 225 mm2 times pi. If the concentration of the electrons achieves a radius of five mm or d2 is about 10 mm, then the area (π r2) is about 25 mm2 times pi. The ratio of the two areas is about nine (225π/25π). Thus, there is about nine times less density of current at the larger cathode compared to the traditional cathode having an area of the desired electron beam. Hence, the lifetime of the larger cathode approximates nine times the lifetime of the traditional cathode, though the actual current through the larger cathode and traditional cathode is about the same. Preferably, the area of the cathode 2910 is about 2, 4, 6, 8, 10, 15, 20, or 25 times that of the cross-sectional area of the substantially parallel electron beam 2950. In another embodiment of the invention, the quadrupole magnets 2970 result in an oblong cross-sectional shape of the electron beam 2950. A projection of the oblong cross-sectional shape of the electron beam 2950 onto the X-ray generation source 2948 results in an X-ray beam 3070 that has a small spot in cross-sectional view, which is preferably substantially circular in cross-sectional shape, that is then passed through the patient 2930. The small spot is used to yield an X-ray having enhanced resolution at the patient. Referring now to FIG. 30, in one embodiment, an X-ray is generated close to, but not in, the proton beam path. A proton beam therapy system and an X-ray system combination 3000 is illustrated in FIG. 30. The proton beam therapy system has a proton beam 268 in a transport system after the Lamberson extraction magnet 292 of the synchrotron 130. The proton beam is directed by the scanning/targeting/delivery system 140 to a tumor 2120 of a patient 2130. The X-ray system 3005 includes an electron beam source 2905 generating an electron beam 2950. The electron beam is directed to an X-ray generation source 2948, such as a piece of tungsten. Preferably, the tungsten X-ray source is located about 1, 2, 3, 5, 10, 15, or 20 millimeters from the proton beam path 268. When the electron beam 2950 hits the tungsten, X-rays are generated in all directions. X-rays are blocked with a port 3062 and are selected for an X-ray beam path 3070. The X-ray beam path 3070 and proton beam path 268 run substantially in parallel as they progress to the tumor 2120. The distance between the X-ray beam path 3070 and proton beam path 269 preferably diminishes to near zero and/or the X-ray beam path 3070 and proton beam path 269 overlap by the time they reach the tumor 2120. Simple geometry shows this to be the case given the long distance, of at least a meter, between the tungsten and the tumor 2120. The distance is illustrated as a gap 3080 in FIG. 30. The X-rays are detected at an X-ray detector 3090, which is used to form an image of the tumor 2120 and/or position of the patient 2130. As a whole, the system generates an X-ray beam that lies in substantially the same path as the proton therapy beam. The X-ray beam is generated by striking a tungsten or equivalent material with an electron beam. The X-ray generation source is located proximate to the proton beam path. Geometry of the incident electrons, geometry of the X-ray generation material, and/or geometry of the X-ray beam blocker 262 yield an X-ray beam that runs either substantially in parallel with the proton beam or results in an X-ray beam path that starts proximate the proton beam path an expands to cover and transmit through a tumor cross-sectional area to strike an X-ray detector array or film allowing imaging of the tumor from a direction and alignment of the proton therapy beam. The X-ray image is then used to control the charged particle beam path to accurately and precisely target the tumor, and/or is used in system verification and validation. Referring now to FIG. 31, additional geometry of the electron beam path 2950 and X-ray beam path 3070 is illustrated. Particularly, the electron beam 2950 is shown as an expanded electron beam path 2952, 2954. Also, the X-ray beam path 3070 is shown as an expanded X-ray beam path 3072, 3074. Referring now to FIG. 32, a 3-dimensional (3-D) X-ray tomography system 3200 is presented. In a typical X-ray tomography system, the X-ray source and detector rotationally translate about a stationary subject. In the X-ray tomography system described herein, the X-ray source and detector are stationary and the patient 2130 rotates. The stationary X-ray source allows a system where the X-ray source 2948 is proximate the proton therapy beam path 268, as described supra. In addition, the rotation of the patient 2130 allows the proton dosage to be distributed around the body, rather than being concentrated on one static entrance side of the body. Further, the 3-D X-ray tomography system allows for simultaneous updates of the tumor position relative to body constituents in real-time during proton therapy treatment of the tumor 2120 in the patient 2130. The X-ray tomography system is further described, infra. Patient Imaging with Rotation In a first step of the X-ray tomography system 3200, the patient 2130 is positioned relative to the X-ray beam path 3070 and proton beam path 268 using a patient semi-immobilization/placement system, described infra. After patient 2130 positioning, a series of reference 2-D X-ray images are collected, on a detector array 3090 or film, of the patient 2130 and tumor 2120 as the subject is rotated about a y-axis 2117. For example, a series of about 50, 100, 200, or 400 X-ray images of the patient are collected as the patient is rotated. In a second example, an X-ray image is collected with each n degrees of rotation of the patient 2130, where n is about ½, 1, 2, 3, 5, 10, or 20 degrees of rotation. Preferably, about 200 images are collected during one full rotation of the patient through 360 degrees. Subsequently, using the reference 2-D X-ray images, an algorithm produces a reference 3-D picture of the tumor 2120 relative to the patient's constituent body parts. A tumor 2120 irradiation plan is made using the 3-D picture of the tumor 2120 and the patient's constituent body parts. Creation of the proton irradiation plan is optionally performed after the patient has moved from the X-ray imaging area. In a second step, the patient 2130 is repositioned relative to the X-ray beam path 3070 and proton beam path 268 using the patient semi-immobilization/placement system. Just prior to implementation of the proton irradiation plan, a few comparative X-ray images of the patient 2130 and tumor 2120 are collected at a limited number of positions using the X-ray tomography system 2600 setup. For example, a single X-ray image is collected with the patient positioned straight on, at angles of plus/minus forty-five degrees, and/or at angles of plus/minus ninety degrees relative to the proton beam path 268. The actual orientation of the patient 2130 relative to the proton beam path 268 is optionally any orientation. The actual number of comparative X-ray images is also optionally any number of images, though the preferable number of comparative X-ray images is about 2 to 5 comparative images. The comparative X-ray images are compared to the reference X-ray images and differences are detected. A medical expert or an algorithm determines if the difference between the reference images and the comparative images is significant. Based upon the differences, the medical expert or algorithm determines if: proton treatment should commence, be halted, or adapted in real-time. For example, if significant differences in the X-ray images are observed, then the treatment is preferably halted and the process of collecting a reference 3-D picture of the patient's tumor is reinitiated. In a second example, if the differences in the X-ray images are observed to be small, then the proton irradiation plan commences. In a third example, the algorithm or medical expert can adapt the proton irradiation plan in real-time to adjust for differences in tumor location resulting from changes in position of the tumor 2120 in the patient 2130 or from differences in the patient 2130 placement. In the third example, the adaptive proton therapy increases patient throughput and enhances precision and accuracy of proton irradiation of the tumor 2120 relative to the healthy tissue of the patient 2130. Patient Immobilization Accurate and precise delivery of a proton beam to a tumor of a patient requires: (1) positioning control of the proton beam and (2) positioning control of the patient. As described, supra, the proton beam is controlled using algorithms and magnetic fields to a diameter of about 0.5, 1, or 2 millimeters. This section addresses partial immobilization, restraint, and/or alignment of the patient to insure the tightly controlled proton beam efficiently hits a target tumor and not surrounding healthy tissue as a result of patient movement. Herein, an x-, y-, and z-axes coordinate system and rotation axis is used to describe the orientation of the patient relative to the proton beam. The z-axis represent travel of the proton beam, such as the depth of the proton beam into the patient. When looking at the patient down the z-axis of travel of the proton beam, the x-axis refers to moving left or right across the patient and the y-axis refers to movement up or down the patient. A first rotation axis is rotation of the patient about the y-axis and is referred to herein as a rotation axis, bottom unit 2112 rotation axis, or y-axis of rotation 2117. In addition, tilt is rotation about the x-axis, yaw is rotation about the y-axis, and roll is rotation about the z-axis. In this coordinate system, the proton beam path 269 optionally runs in any direction. As an illustrative matter, the proton beam path running through a treatment room is described as running horizontally through the treatment room. In this section, three examples of positioning systems are provided: (1) a semi-vertical partial immobilization system 3300; (2) a sitting partial immobilization system 3400; and (3) a laying position 3500. Elements described for one immobilization system apply to other immobilization systems with small changes. For example, a headrest, a head support, or head restraint will adjust along one axis for a reclined position, along a second axis for a seated position, and along a third axis for a laying position. However, the headrest itself is similar for each immobilization position. Vertical Patient Positioning/Immobilization Referring now to FIG. 33, the semi-vertical patient positioning system 3300 is preferably used in conjunction with proton therapy of tumors in the torso. The patient positioning and/or immobilization system controls and/or restricts movement of the patient during proton beam therapy. In a first partial immobilization embodiment, the patient is positioned in a semi-vertical position in a proton beam therapy system. As illustrated, the patient is reclining at an angle alpha, α, about 45 degrees off of the y-axis as defined by an axis running from head to foot of the patient. More generally, the patient is optionally completely standing in a vertical position of zero degrees off the of y-axis or is in a semi-vertical position alpha that is reclined about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65 degrees off of the y-axis toward the z-axis. Patient positioning constraints 3315 that are used to maintain the patient in a treatment position, include one or more of: a seat support 3320, a back support 3330, a head support 3340, an arm support 3350, a knee support 3360, and a foot support 3370. The constraints are optionally and independently rigid or semi-rigid. Examples of a semi-rigid material include a high or low density foam or a visco-elastic foam. For example the foot support is preferably rigid and the back support is preferably semi-rigid, such as a high density foam material. One or more of the positioning constraints 3315 are movable and/or under computer control for rapid positioning and/or immobilization of the patient. For example, the seat support 3320 is adjustable along a seat adjustment axis 3322, which is preferably the y-axis; the back support 3330 is adjustable along a back support axis 3332, which is preferably dominated by z-axis movement with a y-axis element; the head support 3340 is adjustable along a head support axis 3342, which is preferably dominated by z-axis movement with a y-axis element; the arm support 3350 is adjustable along an arm support axis 3352, which is preferably dominated by z-axis movement with a y-axis element; the knee support 3360 is adjustable along a knee support axis 3362, which is preferably dominated by z-axis movement with a y-axis element; and the foot support 3370 is adjustable along a foot support axis 3372, which is preferably dominated by y-axis movement with a z-axis element. If the patient is not facing the incoming proton beam, then the description of movements of support elements along the axes change, but the immobilization elements are the same. An optional camera 3380 is used with the patient immobilization system. The camera views the patient/subject 2130 creating a video image. The image is provided to one or more operators of the charged particle beam system and allows the operators a safety mechanism for determining if the subject has moved or desires to terminate the proton therapy treatment procedure. Based on the video image, the operators optionally suspend or terminate the proton therapy procedure. For example, if the operator observes via the video image that the subject is moving, then the operator has the option to terminate or suspend the proton therapy procedure. An optional video display or display monitor 3390 is provided to the patient. The video display optionally presents to the patient any of: operator instructions, system instructions, status of treatment, or entertainment. Motors for positioning the patient positioning constraints 3315, the camera 3380, and/or video display 3390 are preferably mounted above or below the proton transport path 268 or momentary proton scanning path 269. Respiration control is optionally performed by using the video display. As the patient breathes, internal and external structures of the body move in both absolute terms and in relative terms. For example, the outside of the chest cavity and internal organs both have absolute moves with a breath. In addition, the relative position of an internal organ relative to another body component, such as an outer region of the body, a bone, support structure, or another organ, moves with each breath. Hence, for more accurate and precise tumor targeting, the proton beam is preferably delivered at a point in time where the position of the internal structure or tumor is well defined, such as at the bottom or top of each breath. The video display is used to help coordinate the proton beam delivery with the patient's respiration cycle. For example, the video display optionally displays to the patient a command, such as a hold breath statement, a breathe statement, a countdown indicating when a breath will next need to be held, or a countdown until breathing may resume. Sitting Patient Positioning/Immobilization In a second partial immobilization embodiment, the patient is partially restrained in a seated position 3400. The sitting restraint system uses support structures similar to the support structures in the semi-vertical positioning system, described supra, with an exception that the seat support is replaced by a chair and the knee support is not required. The seated restraint system generally retains the adjustable support, rotation about the y-axis, camera, video, and breath control parameters described in the semi-vertical embodiment, described supra. Referring now to FIG. 34, a particular example of a sitting patient semi-immobilization system 3400 is provided. The sitting system is preferably used for treatment of head and/or neck tumors. As illustrated, the patient is positioned in a seated position on a chair 3410 for particle therapy. The patient is further immobilized using any of the: the head support 3340, the back support 3330, the hand support 3350, the knee support 3360, and the foot support 3370. The supports 3320, 3330, 3340, 3350, 3360, 3370 preferably have respective axes of adjustment 3322, 3332, 3342, 3352, 3362, 3372 as illustrated. The chair 3410 is either readily removed to allow for use of a different patient constraint system or adapts under computer control to a new patient position, such as the semi-vertical system. Laying Patient Positioning/Immobilization In a third partial immobilization embodiment, the patient is partially restrained in a laying position. Referring now to FIG. 34, the laying restraint system 3500 has support structures that are similar to the support structures used in the sitting positioning system 3400 and semi-vertical positioning system 3300, described supra. In the laying position, optional restraint, support, or partial immobilization elements include one or more of: the head support 3340 and the back support, hip, and shoulder 3330 support. The supports preferably have respective axes of adjustment that are rotated as appropriate for a laying position of the patient. The laying position restraint system generally retains the adjustable supports, rotation about the y-axis, camera, video, and breath control parameters described in the semi-vertical embodiment, described supra. If the patient is very sick, such as the patient has trouble standing for a period of about one to three minutes required for treatment, then being in a partially supported system can result in some movement of the patient due to muscle strain. In this and similar situations, treatment of a patient in a laying position on a support table 3520 is preferentially used. The support table has a horizontal platform to support the bulk of the weight of the patient. Preferably, the horizontal platform is detachable from a treatment platform. In a laying positioning system 3500, the patient is positioned on a platform 3510, which has a substantially horizontal portion for supporting the weight of the body in a horizontal position. Optional hand grips are used, described infra. In one embodiment, the platform 3510 affixes relative to the table 3520 using a mechanical stop or lock element 3530 and matching key element 3535 and/or the patient 2130 is aligned or positioned relative to a placement element 3560. Additionally, upper leg support 3544, lower leg support 3540, and/or arm support 3550 elements are optionally added to raise, respectively, an arm or leg out of the proton beam path 269 for treatment of a tumor in the torso or to move an arm or leg into the proton beam path 269 for treatment of a tumor in the arm or leg. This increases proton delivery efficiency, as described supra. The leg supports 3540, 3544 and arm support 3550 are each optionally adjustable along support axes or arcs 3542, 3546, 3552. One or more leg support elements are optionally adjustable along an arc to position the leg into the proton beam path 269 or to remove the leg from the proton beam path 269, as described infra. An arm support element is preferably adjustable along at least one arm adjustment axis or along an arc to position the arm into the proton beam path 269 or to remove the arm from the proton beam path 269, as described infra. Preferably, the patient is positioned on the platform 3510 in an area or room outside of the proton beam path 268 and is wheeled or slid into the treatment room or proton beam path area. For example, the patient is wheeled into the treatment room on a gurney where the top of the gurney, which is the platform, detaches and is positioned onto a table. The platform is preferably lifted onto the table or slid onto the table so that the gurney or bed need not be lifted onto the table. The semi-vertical patient positioning system 3300 and sitting patient positioning system 3400 are preferentially used to treatment of tumors in the head or torso due to efficiency. The semi-vertical patient positioning system 3300, sitting patient positioning system 3400, and laying patient positioning system 3500 are all usable for treatment of tumors in the patient's limbs. Support System Elements Positioning constraints 3315 include all elements used to position the patient, such as those described in the semi-vertical positioning system 3300, sitting positioning system 3400, and laying positioning system 3500. Preferably, positioning constraints or support system elements are aligned in positions that do not impede or overlap the proton beam path 269. However, in some instances the positioning constraints are in the proton beam path 269 during at least part of the time of treatment of the patient. For instance, a positioning constraint element may reside in the proton beam path 269 during part of a time period where the patient is rotated about the y-axis during treatment. In cases or time periods that the positioning constraints or support system elements are in the proton beam path, then an upward adjustment of proton beam energy is preferably applied that increases the proton beam energy to offset the positioning constraint element impedance of the proton beam. This time period and energy is a function of rotational orientation of the patient. In one case, the proton beam energy is increased by a separate measure of the positioning constraint element impedance determined during a reference scan of the positioning constraint system element or set of reference scans of the positioning constraint element as a function of rotation about the y-axis. For clarity, the positioning constraints 3315 or support system elements are herein described relative to the semi-vertical positioning system 3300; however, the positioning elements and descriptive x-, y-, and z-axes are adjustable to fit any coordinate system, to the sitting positioning system 3400, or the laying positioning system 3500. An example of a head support system is described to support, align, and/or restrict movement of a human head. The head support system preferably has several head support elements including any of: a back of head support, a right of head alignment element, and a left of head alignment element. The back of head support element is preferably curved to fit the head and is optionally adjustable along a head support axis, such as along the z-axis. Further, the head supports, like the other patient positioning constraints, is preferably made of a semi-rigid material, such as a low or high density foam, and has an optional covering, such as a plastic or leather. The right of head alignment element and left of head alignment elements or head alignment elements, are primarily used to semi-constrain movement of the head or to fully immobilize the head. The head alignment elements are preferably padded and flat, but optionally have a radius of curvature to fit the side of the head. The right and left head alignment elements are preferably respectively movable along translation axes to make contact with the sides of the head. Restricted movement of the head during proton therapy is important when targeting and treating tumors in the head or neck. The head alignment elements and the back of head support element combine to restrict tilt, rotation or yaw, roll and/or position of the head in the x-, y-, z-axes coordinate system. Referring now to FIG. 36 another example of a head support system 3600 is described for positioning and/or restricting movement of a human head 2102 during proton therapy of a solid tumor in the head or neck. In this system, the head is restrained using 1, 2, 3, 4, or more straps or belts, which are preferably connected or replaceably connected to a back of head support element 3610. In the example illustrated, a first strap 3620 pulls or positions the forehead to the head support element 3610, such as by running predominantly along the z-axis. Preferably a second strap 3630 works in conjunction with the first strap 3620 to prevent the head from undergoing tilt, yaw, roll or moving in terms of translational movement on the x-, y-, and z-axes coordinate system. The second strap 3630 is preferably attached or replaceable attached to the first strap 3620 at or about: (1) a forehead position 3632; (2) at a position on one or both sides of the head 3634; and/or (3) at or about a position on the support element 3636. A third strap 3640 preferably orientates the chin of the subject relative to the support element 3610 by running dominantly along the z-axis. A fourth strap 3650 preferably runs along a predominantly y- and z-axes to hold the chin relative to the head support element 3610 and/or proton beam path. The third 3640 strap preferably is attached to or is replaceably attached to the fourth strap 3650 during use at or about the patient's chin position 3642. The second strap 3630 optionally connects 3636 to the fourth strap 3650 at or about the support element 3610. The four straps 3620, 3630, 3640, 3650 are illustrative in pathway and interconnection. Any of the straps optionally hold the head along different paths around the head and connect to each other in separate fashion. Naturally, a given strap preferably runs around the head and not just on one side of the head. Any of the straps 3620, 3630, 3640, and 3650 are optionally used independently or in combinations and permutations with the other straps. The straps are optionally indirectly connected to each other via a support element, such as the head support element 3610. The straps are optionally attached to the head support element 3610 using hook and loop technology, a buckle, or fastener. Generally, the straps combine to control position, front-to-back movement of the head, side-to-side movement of the head, tilt, yaw, roll, and/or translational position of the head. The straps are preferably of known impedance to proton transmission allowing a calculation of peak energy release along the z-axis to be calculated. For example, adjustment to the Bragg peak energy is made based on the slowing tendency of the straps to proton transport. Referring now to FIG. 37, still another example of a head support system 3340 is described. The head support 3340 is preferably curved to fit a standard or child sized head. The head support 3340 is optionally adjustable along a head support axis 3342. Further, the head supports, like the other patient positioning constraints, is preferably made of a semi-rigid material, such as a low or high density foam, and has an optional covering, such as a plastic or leather. Elements of the above described head support, head positioning, and head immobilization systems are optionally used separately or in combination. Still referring to FIG. 37, an example of the arm support 3350 is further described. The arm support preferably has a left hand grip 3710 and a right hand grip 3720 used for aligning the upper body of the patient 2130 through the action of the patient 2130 gripping the left and right hand grips 3710, 3720 with the patient's hands 2134. The left and right hand grips 3710, 3720 are preferably connected to the arm support 3350 that supports the mass of the patient's arms. The left and right hand grips 3710, 3720 are preferably constructed using a semi-rigid material. The left and right hand grips 3710, 3720 are optionally molded to the patient's hands to aid in alignment. The left and right hand grips optionally have electrodes, as described supra. Patient Respiration Monitoring Preferably, the patient's respiration pattern is monitored. When a subject or patient 2130 is breathing many portions of the body move with each breath. For example, when a subject breathes the lungs move as do relative positions of organs within the body, such as the stomach, kidneys, liver, chest muscles, skin, heart, and lungs. Generally, most or all parts of the torso move with each breath. Indeed, the inventors have recognized that in addition to motion of the torso with each breath, various motion also exists in the head and limbs with each breath. Motion is to be considered in delivery of a proton dose to the body as the protons are preferentially delivered to the tumor and not to surrounding tissue. Motion thus results in an ambiguity in where the tumor resides relative to the beam path. To partially overcome this concern, protons are preferentially delivered at the same point in each of a series of respiration cycles. Initially a rhythmic pattern of breathing of a subject is determined. The cycle is observed or measured. For example, an X-ray beam operator or proton beam operator can observe when a subject is breathing or is between breaths and can time the delivery of the protons to a given period of each breath. Alternatively, the subject is told to inhale, exhale, and/or hold their breath and the protons are delivered during the commanded time period. Preferably, one or more sensors are used to determine the respiration cycle of the individual. Two examples of a respiration monitoring system 4010 are provided: (1) a thermal monitoring system and (2) a force monitoring system. Referring again to FIG. 35, a first example of the thermal respiration monitoring system is provided. In the thermal respiration monitoring system, a sensor is placed by the nose and/or mouth of the patient. As the jaw of the patient is optionally constrained, as described supra, the thermal respiration monitoring system is preferably placed by the patient's nose exhalation path. To avoid steric interference of the thermal sensor system components with proton therapy, the thermal respiration monitoring system is preferably used when treating a tumor not located in the head or neck, such as a when treating a tumor in the torso or limbs. In the thermal monitoring system, a first thermal resistor 3670 is used to monitor the patient's respiration cycle and/or location in the patient's respiration cycle. Preferably, the first thermal resistor 3670 is placed by the patient's nose, such that the patient exhaling through their nose onto the first thermal resistor 3670 warms the first thermal resistor 3670 indicating an exhale. Preferably, a second thermal resistor 3660 operates as an environmental temperature sensor. The second thermal resistor 3660 is preferably placed out of the exhalation path of the patient but in the same local room environment as the first thermal resistor 3670. Generated signal, such as current from the thermal resistors 3670, 3660, is preferably converted to voltage and communicated with the main controller 110 or a sub-controller of the main controller. Preferably, the second thermal resistor 3660 is used to adjust for the environmental temperature fluctuation that is part of a signal of the first thermal resistor 3670, such as by calculating a difference between the values of the thermal resistors 3670, 3660 to yield a more accurate reading of the patient's respiration cycle. Referring again to FIG. 34, a second example of a monitoring system is provided. In an example of a force respiration monitoring system, a sensor is placed by the torso. To avoid steric interference of the force sensor system components with proton therapy, the force respiration monitoring system is preferably used when treating a tumor located in the head, neck, or limbs. In the force monitoring system, a belt or strap 3450 is placed around an area of the patient's torso that expands and contracts with each respiration cycle of the patient. The belt 3450 is preferably tight about the patient's chest and is flexible. A force meter 3452 is attached to the belt and senses the patients respiration pattern. The forces applied to the force meter 3452 correlate with periods of the respiration cycle. The signals from the force meter 3452 are preferably communicated with the main controller 110 or a sub-controller of the main controller. Coordinated Charged Particle Beam Control In this section, charged particle beam control systems, described supra, are coordinated for cancer therapy. Positioning, Imaging, and Irradiation Referring now to FIG. 38, a method of cancer therapy is provided. In this method, the patient is first positioned 3810, then the tumor is imaged 3820, subsequently a charged particle irradiation plan is developed 3830, and then the charged particle irradiation plan is implemented 3840. Further examples of the steps provided in FIG. 38 are described, infra, along with additional optional steps. For example, the positioning, imaging, and irradiation steps are optionally integrated with patient translation control, patient rotation control, and/or patient respiration control. Additionally, any of the steps described herein are optionally coordinated with charged particle beam generation, acceleration, extraction, and/or delivery. Additionally, any of the steps are optionally coordinated with x-, y-axis beam trajectory control, delivered energy control, delivered intensity control, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. Tumor Imaging Referring now to FIG. 39, a method of tumor imaging is provided. In a first step, the patient is positioned 3810, such as with the patient immobilization and/or positioning systems described supra. Subsequently, the tumor is imaged 3820, such as with the imaging/X-ray system described supra. Preferably, each image is a 2-dimensional image. If the image is not complete 3910, then the patient is rotated 3920, such as with the multi-field irradiation rotatable platform described supra. For instance, the image is collected with rotation of the patient about the y-axis 2117. After rotation of n degrees of rotation of the patient 2130, where n is about ½, 1, 2, 3, 5, 10, or 20 degrees, another image is collected 3820. The imaging 3820 and rotation 3920 processes are repeated until the tumor 2120 is suitably imaged. A 3-dimensional image is created 3930 using the two-dimensional images collected as a function of patient rotation. Respiration Control Referring now to FIG. 40, a patient is positioned 3810 and once the rhythmic pattern of the subject's breathing or respiration cycle is determined 4010, a signal is optionally delivered to the patient, such as via the display monitor 3390, to more precisely control the breathing frequency 4020. For example, the display screen 3390 is placed in front of the patient and a message or signal is transmitted to the display screen 3390 directing the subject when to hold their breath and when to breathe. Typically, a respiration control module uses input from one or more of the respiration sensors. For example, the input is used to determine when the next breath exhale is to complete. At the bottom of the breath, the control module displays a hold breath signal to the subject, such as on a monitor, via an oral signal, digitized and automatically generated voice command, or via a visual control signal. Preferably, a display monitor 3390 is positioned in front of the subject and the display monitor displays breathing commands to the subject. Typically, the subject is directed to hold their breath for a short period of time, such as about ½, 1, 2, 3, 5, or 10 seconds. The period of time the breath is held is preferably synchronized to the delivery time of the proton beam to the tumor, which is about ½, 1, 2, or 3 seconds. While delivery of the protons at the bottom of the breath is preferred, protons are optionally delivered at any point in the respiration cycle, such as upon full inhalation. Delivery at the top of the breath or when the patient is directed to inhale deeply and hold their breath by the respiration control module is optionally performed as at the top of the breath the chest cavity is largest and for some tumors the distance between the tumor and surrounding tissue is maximized or the surrounding tissue is rarefied as a result of the increased volume. Hence, protons hitting surrounding tissue is minimized. Optionally, the display screen tells the subject when they are about to be asked to hold their breath, such as with a 3, 2, 1, second countdown so that the subject is aware of the task they are about to be asked to perform. X-Ray Synchronization with Patient Respiration In one embodiment, X-ray images are collected in synchronization with patient respiration. The synchronization enhances X-ray image clarity by removing position ambiguity due to the relative movement of body constituents during a patient respiration cycle. In a second embodiment, an X-ray system is orientated to provide X-ray images of a patient in the same orientation as viewed by a proton therapy beam, is synchronized with patient respiration, is operable on a patient positioned for proton therapy, and does not interfere with a proton beam treatment path. Preferably, the synchronized system is used in conjunction with a negative ion beam source, synchrotron, and/or targeting method and apparatus to provide an X-ray timed with patient respiration. Preferably, X-ray images are collected immediately prior to and/or concurrently with particle beam therapy irradiation to ensure targeted and controlled delivery of energy relative to a patient position resulting in efficient, precise, and/or accurate in-vivo treatment of a solid cancerous tumor with minimization of damage to surrounding healthy tissue. An X-ray delivery control algorithm is used to synchronize delivery of the X-rays to the patient 2130 within a given period of each breath, such as at the top or bottom of a breath, and/or when the subject is holding their breath. For clarity of combined X-ray images, the patient is preferably both accurately positioned and precisely aligned relative to the X-ray beam path 3070. The X-ray delivery control algorithm is preferably integrated with the respiration control module. Thus, the X-ray delivery control algorithm knows when the subject is breathing, where in the respiration cycle the subject is, and/or when the subject is holding their breath. In this manner, the X-ray delivery control algorithm delivers X-rays at a selected period of the respiration cycle. Accuracy and precision of patient alignment allow for (1) more accurate and precise location of the tumor 2120 relative to other body constituents and (2) more accurate and precise combination of X-rays in generation of a 3-dimensional X-ray image of the patient 2130 and tumor 2120. Referring again to FIG. 40, an example of generating an X-ray image of the patient 2130 and tumor 2120 using the X-ray generation device 3000 or 3-dimensional X-ray generation device 3000 as a known function of time of the patient's respiration cycle is provided. In one embodiment, as a first step the main controller 110 instructs, monitors, and/or is informed of patient positioning 3810. In a first example of patient positioning 3810, the automated patient positioning system, described supra, under main controller 110 control, is used to align the patient 2130 relative to the X-ray beam path 3070. In a second example of patient positioning, the main controller 110 is told via sensors or human input that the patient 2130 is aligned. In a second step, patient respiration is then monitored 4010, as described infra. As a first example of respiration monitoring, an X-ray is collected 4030 at a known point in the patient respiration cycle. In a second example of respiration monitoring, the patient's respiration cycle is first controlled in a third step of controlling patient respiration 4020 and then as a fourth step an X-ray is collected 4030 at a controlled point in the patient respiration cycle. Preferably, the cycle of patient positioning 3810, patient respiration monitoring 4010, patient respiration control 4020, and collecting an X-ray 4030 is repeated with different patient positions. For example, the patient 2130 is rotated about an axis 2117 and X-rays are collected as a function of the rotation. In a fifth step, a 3-dimensional X-ray image 4040 is generated of the patient 2130, tumor 2120, and body constituents about the tumor using the collected X-ray images, such as with the 3-dimensional X-ray generation device 3000, described supra. The patient respiration monitoring and control steps are further described, infra. An X-ray timed with patient respiration where the X-ray is preferably collected immediately prior to and/or concurrently with particle beam therapy irradiation to ensure targeted and controlled delivery of energy relative to a patient position resulting in efficient, precise, and/or accurate treatment of a solid cancerous tumor with minimization of damage to surrounding healthy tissue in a patient using the proton beam position verification system. Proton Beam Therapy Synchronization with Respiration In one embodiment, charged particle therapy and preferably multi-field proton therapy is coordinated and synchronized with patient respiration via use of the respiration feedback sensors, described supra, used to monitor and/or control patient respiration. Preferably, the charged particle therapy is performed on a patient in a partially immobilized and repositionable position and the proton delivery to the tumor 2120 is timed to patient respiration via control of charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus. The synchronization enhances proton delivery accuracy by removing position ambiguity due to the relative movement of body constituents during a patient respiration cycle. Synchrotron control to deliver protons at a desired point in the respiration cycle is described infra. In a second embodiment, the X-ray system, described supra, is used to provide X-ray images of a patient in the same orientation as viewed by a proton therapy beam and both the X-ray system and the proton therapy beam are synchronized with patient respiration. Again, synchrotron control to deliver protons at a desired point in the respiration cycle is described infra. A proton delivery control algorithm is used to synchronize delivery of the protons to the tumor within a given period of each breath, such as at the top of a breath, at the bottom of a breath, and/or when the subject is holding their breath. The proton delivery control algorithm is preferably integrated with the respiration control module. Thus, the proton delivery control algorithm knows when the subject is breathing, where in the respiration cycle the subject is, and/or when the subject is holding their breath. The proton delivery control algorithm controls when protons are injected and/or inflected into the synchrotron, when an RF signal is applied to induce an oscillation, as described supra, and when a DC voltage is applied to extract protons from the synchrotron, as described supra. Typically, the proton delivery control algorithm initiates proton inflection and subsequent RF induced oscillation before the subject is directed to hold their breath or before the identified period of the respiration cycle selected for a proton delivery time. In this manner, the proton delivery control algorithm delivers protons at a selected period of the respiration cycle by simultaneously or nearly simultaneously delivering the high DC voltage to the second pair of plates, described supra, which results in extraction of the protons from the synchrotron and subsequent delivery to the subject at the selected time point. Since the period of acceleration of protons in the synchrotron is constant or known for a desired energy level of the proton beam, the proton delivery control algorithm is used to set an AC RF signal that matches the respiration cycle or directed respiration cycle of the subject. The above described charged particle therapy elements are combined in combinations and/or permutations in developing and implementing a tumor treatment plan, described infra. Proton Beam Generation, Injection, Acceleration, Extraction, and Delivery Referring now to FIG. 41, an example of implementation of the irradiation plan 3840 is provided. The multi-axis and/or multi-field charged particle cancer therapy system elements described herein are preferably coordinated with charged particle delivery 4100. After patient positioning 3810 and reading the irradiation plan instructions 4110, hydrogen is injected 4115 into the negative ion source 310, plasma is generated 4120, a negative ion is extracted 4125, and the negative ion is accelerated 4130, converted into a positive ion 4140, and injected into the synchrotron 4145. Subsequently, the positive ion is accelerated 4150, extraction is initiated 4155, intensity of the irradiation beam is controlled 4160, extraction of the charged particle beam is performed 4165, and the tumor is irradiated 4170. Preferably, one or more elements of the charged particle delivery 4100 system are timed with patient respiration. After tumor irradiation 4170, the patient is preferably rotated 3920 and the irradiation sequence is repeated yielding multi-field irradiation of the tumor 2120. The entire sequence is optionally performed using the intensity modulated 3-dimensional scanning system 2800, described supra. Multi-Axis Charged Particle Irradiation Referring now to FIG. 42, another example of implementation of the irradiation plan 3840 is provided. In this example, a multi-axis charged particle beam therapy system is provided, where multi-axis refers to independent control of: x-axis beam control, y-axis beam control, delivered beam energy, and/or delivered beam intensity. The multi-axis control is preferably implemented with multi-field charge particle irradiation, such as via use of independent control of rotation and/or translation of the patient. In this example, the main controller 110 independently adjusts x-axis targeting of the proton beam 4210, y-axis targeting of the proton beam 4220, rotational position of the patient 4230, delivered energy of the proton beam 4240, and/or delivered intensity of the proton beam in the step of irradiating the tumor 3840. The process is optionally repeated or iterated using a continuously irradiating and scanning charged particle irradiation system as described using the 3-dimensional scanning system 2800. Developing and Implementing a Tumor Irradiation Plan A series of steps are performed to design and execute a radiation treatment plan for treating a tumor 2120 in a patient 2130. The steps include one or more of: positioning and immobilizing the patient; recording the patient position; monitoring patient respiration; controlling patient respiration; collecting multi-field images of the patient to determine tumor location relative to body constituents; developing a radiation treatment plan; repositioning the patient; verifying tumor location; and irradiating the tumor. In this section, an overview of developing the irradiation plan and subsequent implementation of the irradiation plan is initially presented, the individual steps are further described, and a more detailed example of the process is then described. Referring now to FIG. 43, an overview of a system for development of an irradiation plan and subsequent implementation of the irradiation plan 4300 is provided. Preferably, all elements of the positioning, respiration monitoring, imaging, and tumor irradiation system 4300 are under main controller 110 control. Initially, the tumor containing volume of the patient 2130 is positioned and immobilized 3810 in a controlled and reproducible position. The process of positioning and immobilizing 3810 the patient 2310 is preferably iterated 4312 until the position is accepted. The position is preferably digitally recorded 4315 and is later used in a step of computer controlled repositioning of the patient 4317 in the minutes or seconds prior to implementation of the irradiation element 3840 of the tumor treatment plan. The process of positioning the patient in a reproducible fashion and reproducibly aligning the patient 2310 to the controlled position is further described, infra. Subsequent to patient positioning 3810, the steps of monitoring 4010 and preferably controlling 4020 the respiration cycle of the patient 2130 are preferably performed to yield more precise positioning of the tumor 2120 relative to other body constituents, as described supra. Multi-field images of the tumor are then collected 4340 in the controlled, immobilized, and reproducible position. For example, multi-field X-ray images of the tumor 2120 are collected using the X-ray source proximate the proton beam path, as described supra. The multi-field images are optionally from three or more positions and/or are collected while the patient is rotated, as described supra. At this point the patient 2130 is either maintained in the treatment position or is allowed to move from the controlled treatment position while an oncologist processes the multi-field images 4345 and generates a tumor treatment plan 4350 using the multi-field images. Optionally, the tumor irradiation plan is implemented 3840 at this point in time. Typically, in a subsequent treatment center visit, the patient 2130 is repositioned 4317. Preferably, the patient's respiration cycle is again monitored 4012 and/or controlled 4022, such as via use of the thermal monitoring respiration sensors, force monitoring respiration sensor, and/or via commands sent to the display monitor 3390, described supra. Once repositioned, verification images are collected 4360, such as X-ray location verification images from 1, 2, or 3 directions. For example, verification images are collected with the patient facing the proton beam and at rotation angles of 90, 180, and 270 degrees from this position. At this point, comparing the verification images to the original multi-field images used in generating the treatment plan, the algorithm or preferably the oncologist determines if the tumor 2120 is sufficiently repositioned 4365 relative to other body parts to allow for initiation of tumor irradiation using the charged particle beam. Essentially, the step of accepting the final position of the patient 4365 is a safety feature used to verify that that the tumor 2120 in the patient 2130 has not shifted or grown beyond set specifications. At this point the charged particle beam therapy commences 3840. Preferably the patient's respiration is monitored 4014 and/or controlled 4024, as described supra, prior to commencement of the charged particle beam treatment 3840. Optionally, simultaneous X-ray imaging 4390 of the tumor 2120 is performed during the multi-field proton beam irradiation procedure and the main controller 110 uses the X-ray images to adapt the radiation treatment plan in real-time to account for small variations in movement of the tumor 2120 within the patient 2130. Herein the steps of monitoring 4010, 4012, 4014 and controlling 4020, 4022, 4024 the patient's respiration are optional, but preferred. The steps of monitoring and controlling the patient's respiration are performed before and/or during the multi-filed imaging 4340, position verification 4360, and/or tumor irradiation 3840 steps. The patient positioning 3810 and patient repositioning 4317 steps are further described, infra. Coordinated Charged Particle Acceleration and Respiration Rate In yet another embodiment, the charged particle accelerator is synchronized to the patient's respiration cycle. More particularly, synchrotron acceleration cycle usage efficiency is enhanced by adjusting the synchrotron's acceleration cycle to correlate with a patient's respiration rate. Herein, efficiency refers to the duty cycle, the percentage of acceleration cycles used to deliver charged particles to the tumor, and/or the fraction of time that charged particles are delivered to the tumor from the synchrotron. The system senses patient respiration and controls timing of negative ion beam formation, injection of charged particles into a synchrotron, acceleration of the charged particles, and/or extraction to yield delivery of the particles to the tumor at a predetermine period of the patient's respiration cycle. Preferably, one or more magnetic fields in the synchrotron 130 are stabilized through use of a feedback loop, which allows rapid changing of energy levels and/or timing of extraction from pulse to pulse. Further, the feedback loop allows control of the acceleration/extraction to correlate with a changing patient respiration rate. Independent control of charged particle energy and intensity is maintained during the timed irradiation therapy. Multi-field irradiation ensures efficient delivery of Bragg peak energy to the tumor while spreading ingress energy about the tumor. In one example, a sensor, such as the first thermal sensor 3670 or the second thermal sensor 3660, is used to monitor a patient's respiration. A controller, such as the main controller 110, then controls charged particle formation and delivery to yield a charged particle beam delivered at a determined point or duration period of the respiration cycle, which ensures precise and accurate delivery of radiation to a tumor that moves during the respiration process. Optional charged particle therapy elements controlled by the controller include the injector 120, accelerator 132, and/or extraction 134 system. Elements optionally controlled in the injector system 120 include: injection of hydrogen gas into a negative ion source 310, generation of a high energy plasma within the negative ion source, filtering of the high energy plasma with a magnetic field, extracting a negative ion from the negative ion source, focusing the negative ion beam 319, and/or injecting a resulting positive ion beam 262 into the synchrotron 130. Elements optionally controlled in the accelerator 132 include: accelerator coils, applied magnetic fields in turning magnets, and/or applied current to correction coils in the synchrotron. Elements optionally controlled in the extraction system 134 include: radio-frequency fields in an extraction element and/or applied fields in an extraction process. By using the respiration sensor to control delivery of the charged particle beam to the tumor during a set period of the respiration cycle, the period of delivery of the charged particle to the tumor is adjustable to a varying respiration rate. Thus, if the patient breathes faster, the charged particle beam is delivered to the tumor more frequently and if the patient breathes slower, then the charged particle beam is delivered to the tumor less frequently. Optionally, the charged particle beam is delivered to the tumor with each breath of the patient regardless of the patient's changing respiration rate. This lies in stark contrast with a system where the charged particle beam delivers energy at a fixed time interval and the patient must adjust their respiration rate to match the period of the accelerator delivering energy and if the patient's respiration rate does not match the fixed period of the accelerator, then that accelerator cycle is not delivered to the tumor and the acceleration usage efficiency is reduced. Typically, in an accelerator the current is stabilized. A problem with current stabilized accelerators is that the magnets used have memories in terms of both magnitude and amplitude of a sine wave. Hence, in a traditional system, in order to change the circulation frequency of the charged particle beam in a synchrotron, slow changes in current must be used. However, in a second example, the magnetic field controlling the circulation of the charged particles about the synchrotron is stabilized. The magnetic field is stabilized through use of: (1) magnetic field sensors 1650 sensing the magnetic field about the circulating charged particles and (2) a feedback loop through a controller or main controller 110 controlling the magnetic field about the circulating charged particles. The feedback loop is optionally used as a feedback control to the first winding coil 1250 and the second winding coil 1260. However, preferably the feedback loop is used to control the correction coils 1510, 1520, described supra. With the use of the feedback loop described herein using the magnetic field sensors, the frequency and energy level of the synchrotron are rapidly adjustable and the problem is overcome. Further, the use of the smaller correction coils 1510, 1520 allows for rapid adjustment of the accelerator compared to the use of the larger winding coils 1250, 1260, described supra. More particularly, the feedback control allows an adjustment of the accelerator energy from pulse to pulse in the synchrotron 130. In this section, the first example yielded delivery of the charged particle beam during a particular period of the patient's respiration cycle even if the patient's respiration period is varying. In this section, the second example used a magnetic field sensor 1650 and a feedback loop to the correction coils 1510, 1520 to rapidly adjust the energy of the accelerator from pulse to pulse. In a third example, the respiration sensor of the first example is combined with the magnetic field sensor of the second example to control both the timing of the delivery of the charged particle beam from the accelerator and the energy of the charged particle beam from the accelerator. More particularly, the timing of the charged particle delivery is controlled using the respiration sensor, as described supra, and the energy of the charged particle beam is controlled using the magnetic field sensors and feedback loop, as described supra. Still more particularly, a magnetic field controller, such as the main controller 110, takes the input from the respiration sensor and uses the input as: (1) a feedback control to the magnetic fields controlling the circulating charged particles energy and (2) as a feedback control to time the pulse of the charged particle accelerator to the respiration cycle of the patient. This combination allows delivery of the charged particle beam to the tumor with each breath of the patient even if the breathing rate of the patient varies. In this manner, the accelerator efficiency is increased as the cancer therapy system does not need to lose cycles when the patient's breathing is not in phase with the synchrotron charged particle generation rate. Referring now to FIG. 44, the combined use of the respiration sensor and magnetic field sensor 4400 to deliver charged particles at varying energy and at varying time intervals is further described. The main controller 110 controls the injection system 120, charged particle acceleration system 132, extraction system 134, and targeting/delivery system 140. In this embodiment, the previously described respiration monitoring system 4410 of the patient interface module 150 is used as an input to a magnetic field controller 4420. A second input to the magnetic field controller 4420 is a magnetic field sensor 1650. In one case, the respiration rates from the respiration monitoring system 4410 are fed to the main controller 130, which controls the injection system 120 and/or components of the acceleration system 132 to yield a charged particle beam at a chosen period of the respiration cycle, as described supra. In a second case, the respiration data from the respiration monitoring system is used as an input to the magnetic field controller 4420. The magnetic field controller also receives feedback input from the magnetic field sensor 1650. The magnetic field controller thus times charged particle energy delivery to correlate with sensed respiration rates and delivers energy levels of the charged particle beam that are rapidly adjustable with each pulse of the accelerator using the feedback loop through the magnetic field sensor 1650. Referring still to FIG. 44 and now additionally referring to FIG. 45, a further example is used to clarify the magnetic field control using a feedback loop 4400 to change delivery times and/or periods of proton pulse delivery. In one case, a respiratory sensor 4410 senses the respiration cycle of the patient. The respiratory sensor sends the patient's respiration pattern or information to an algorithm in the magnetic field controller 4420, typically via the patient interface module 150 and/or via the main controller 110 or a subcomponent thereof. The algorithm predicts and/or measures when the patient is at a particular point in the respiration cycle, such as at the top or bottom of a breath. One or more magnetic field sensors 1650 are used as inputs to the magnetic field controller 4420, which controls a magnet power supply for a given magnetic, such as within a first turning magnet 1010 of a synchrotron 130. The control feedback loop is thus used to dial the synchrotron to a selected energy level and to deliver protons with the desired energy at a selected point in time, such as at a particular point in the respiration cycle. The selected point in the respiration cycle is optionally anywhere in the respiration cycle and/or for any duration during the respiration cycle. As illustrated in FIG. 45, the selected time period is at the top of a breath for a period of about 0.1, 0.5, 1 seconds. More particularly, the main controller 110 controls injection of hydrogen into the injection system, formation of the negative ion 310, controls extraction of negative ions from negative ion source 310, controls injection 120 of protons into the synchrotron 130, and/or controls acceleration of the protons in a manner that combined with extraction 134 delivers the protons 140 to the tumor at a selected point in the respiration cycle. Intensity of the proton beam is also selectable and controllable by the main controller 130 at this stage, as described supra. The feedback control from the magnetic field controller 4420 is optionally to a power or power supplies for one or both of the main bending magnet 250, described supra, or to the correction coils 1520 within the main bending magnet 250. Having smaller applied currents, the correction coils 1510, 1520 are rapidly adjustable to a newly selected acceleration frequency or corresponding charged particle energy level. Particularly, the magnetic field controller 4420 alters the applied fields to the main bending magnets or correction coils that are tied to the patient's respiration cycle. This system is in stark contrast to a system where the current is stabilized and the synchrotron delivers pulses with a fixed period. Preferably, the feedback of the magnetic field design coupled with the correction coils allows for the extraction cycle to match the varying respiratory rate of the patient, such as where a first respiration period 4510, P1, does not equal a second respiration period 4520, P2. Referring now to FIG. 46, an example of a charged particle cancer therapy system 100 is provided. A main controller receives input from one, two, three, or four of a respiration monitoring and/or controlling controller 4610, a beam controller 4615, a rotation controller 4650, and/or a timing to a time period in a respiration cycle controller 4660. The beam controller 4615 preferably includes one or more or a beam energy controller 4620, the beam intensity controller 1940, a beam velocity controller 4630, and/or a horizontal/vertical beam positioning controller 4640. The main controller 110 controls any element of the injection system 120; the synchrotron 130; the scanning/targeting/delivery system 140; the patient interface module 150; the display system 160; and/or the imaging system 170. For example, the respiration monitoring/controlling controller 4610 controls any element or method associated with the respiration of the patient; the beam controller 4615 controls any of the elements controlling acceleration and/or extraction of the charged particle beam; the rotation controller 4650 controls any element associated with rotation of the patient 2130 or gantry; and the timing to a period in respiration cycle controller 4660 controls any aspects affecting delivery time of the charged particle beam to the patient. As a further example, the beam controller 4615 optionally controls any magnetic and/or electric field about any magnet in the charged particle cancer therapy system 100. Computer Controlled Patient Repositioning One or more of the patient positioning unit components and/or one of more of the patient positioning constraints are preferably under computer control. For example, the computer records or controls the position of the patient positioning elements 3315, such as via recording a series of motor positions connected to drives that move the patient positioning elements 3315. For example, the patient is initially positioned 3810 and constrained by the patient positioning constraints 3315. The position of each of the patient positioning constraints is recorded and saved by the main controller 110, by a sub-controller of the main controller 110, or by a separate computer controller. Then, imaging systems are used to locate the tumor 2120 in the patient 2130 while the patient is in the controlled position of final treatment. Preferably, when the patient is in the controlled position, multi-field imaging is performed, as described herein. The imaging system 170 includes one or more of: MRI's, X-rays, CT's, proton beam tomography, and the like. Time optionally passes at this point while images from the imaging system 170 are analyzed and a proton therapy treatment plan is devised. The patient optionally exits the constraint system during this time period, which may be minutes, hours, or days. Upon, and preferably after, return of the patient and initial patient placement into the patient positioning unit, the computer returns the patient positioning constraints to the recorded positions. This system allows for rapid repositioning of the patient to the position used during imaging and development of the multi-field charged particle irradiation treatment plan, which minimizes setup time of patient positioning and maximizes time that the charged particle beam system 100 is used for cancer treatment. Reproducing Patient Positioning and Immobilization In one embodiment, using a patient positioning and immobilization system 4000, a region of the patient 2130 about the tumor 2120 is reproducibly positioned and immobilized, such as with the motorized patient translation and rotation positioning system 2110 and/or with the patient positioning constraints 3315. For example, one of the above described positioning systems, such as (1) the semi-vertical partial immobilization system 3300; (2) the sitting partial immobilization system 3400; or (3) the laying position system 3500 is used in combination with the patient translation and rotation system 2110 to position the tumor 2120 of the patient 2130 relative to the proton beam path 268. Preferably, the position and immobilization system controls position of the tumor 2120 relative to the proton beam path 268, immobilizes position of the tumor 2120, and facilitates repositioning the tumor 2120 relative to the proton beam path 268 after the patient 2130 has moved away from the proton beam path 268, such as during development of the irradiation treatment plan 4345. Preferably, the tumor 2120 of the patient 2130 is positioned in terms of 3-D location and in terms of orientation attitude. Herein, 3-D location is defined in terms of the x-, y-, and z-axes and orientation attitude is the state of pitch, yaw, and roll. Roll is rotation of a plane about the z-axis, pitch is rotation of a plane about the x-axis, and yaw is the rotation of a plane about the y-axis. Tilt is used to describe both roll and pitch. Preferably, the positioning and immobilization system controls the tumor 2120 location relative to the proton beam path 268 in terms of at least three of and preferably in terms of four, five, or six of: pitch, yaw, roll, x-axis location, y-axis location, and z-axis location. Chair The patient positioning and immobilization system 4000 is further described using a chair positioning example. For clarity, a case of positioning and immobilizing a tumor in a shoulder is described using chair positioning. Using the semi-vertical immobilization system 3300, the patient is generally positioned using the seat support 3320, knee support 3360, and/or foot support 3370. To further position the shoulder, a motor in the back support 3330 pushes against the torso of the patient. Additional arm support 3350 motors align the arm, such as by pushing with a first force in one direction against the elbow of the patient and the wrist of the patient is positioned using a second force in a counter direction. This restricts movement of the arm, which helps to position the shoulder. Optionally, the head support is positioned to further restrict movement of the shoulder by applying tension to the neck. Combined, the patient positioning constraints 3315 control position of the tumor 2120 of the patient 2130 in at least three dimensions and preferably control position of the tumor 2120 in terms of all of yaw, roll, and pitch movement as well as in terms of x-, y-, and z-axis position. For instance, the patient positioning constraints position the tumor 2120 and restricts movement of the tumor, such as by preventing patient slumping. Optionally, sensors in one or more of the patient positioning constraints 3315 record an applied force. In one case, the seat support senses weight and applies a force to support a fraction of the patient's weight, such as about 50, 60, 70, or 80 percent of the patient's weight. In a second case, a force applied to the neck, arm, and/or leg is recorded. Generally, the patient positioning and immobilization system 4000 removes movement degrees of freedom from the patient 2130 to accurately and precisely position and control the position of the tumor 2120 relative to the X-ray beam path 3070, proton beam path 268, and/or an imaging beam path. Further, once the degrees of freedom are removed, the motor positions for each of the patient positioning constraints are recorded and communicated digitally to the main controller 110. Once the patient moves from the immobilization system 4000, such as when the irradiation treatment plan is generated 4350, the patient 2130 must be accurately repositioned in a patient repositioning system 4300 before the irradiation plan is implemented. To accomplish this, the patient 2130 sits generally in the positioning device, such as the chair, and the main controller sends the motor position signals and optionally the applied forces back to motors controlling each of the patient positioning constraints 3315 and each of the patient positioning constraints 3315 are automatically moved back to their respective recorded positions. Hence, re-positioning and re-immobilizing the patient 2130 is accomplished from a time of sitting to fully controlled position in less than about 10, 30, 60, 120, or 600 seconds. Using the computer controlled and automated patient positioning system, the patient is re-positioned in the positioning and immobilization system 4300 using the recalled patient positioning constraint 3315 motor positions; the patient 2130 is translated and rotated using the patient translation and rotation system 2120 relative to the proton beam 268; and the proton beam 268 is scanned to its momentary beam position 269 by the main controller 110, which follows the generated irradiation treatment plan 4350. Tomography In one embodiment, the charged particle tomography apparatus is used to image a tumor in a patient. In another embodiment, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system using common elements. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system that are part of the cancer therapy system, described supra. In various embodiments, the tomography imaging system is optionally simultaneously operational with a charged particle cancer therapy system using common elements, allows tomographic imaging with rotation of the patient, is operational on a patient in an upright, semi-upright, and/or horizontal position, is simultaneously operational with X-ray imaging, and/or allows use of adaptive charged particle cancer therapy. Further, the common tomography and cancer therapy apparatus elements are optionally operational in a multi-axis and/or multi-field raster beam mode. In conventional medical X-ray tomography, a sectional image through a body is made by moving one or both of an X-ray source and the X-ray film in opposite directions during the exposure. By modifying the direction and extent of the movement, operators can select different focal planes, which contain the structures of interest. More modern variations of tomography involve gathering projection data from multiple directions by moving the X-ray source and feeding the data into a tomographic reconstruction software algorithm processed by a computer. Herein, in stark contrast to known methods, the radiation source is a charged particle, such as a proton ion beam or a carbon ion beam. A proton beam is used herein to describe the tomography system, but the description applies to a heavier ion beam, such as a carbon ion beam. Further, in stark contrast to known techniques, herein the radiation source is preferably stationary while the patient is rotated. Referring now to FIG. 47, an example of a tomography apparatus is described. In one example, the tomography system 4700 uses elements in common with the charged particle beam system 100, including elements of one or more of the injection system 120, accelerator 130, targeting/delivery system 140, patient interface module 150, display system 160, and/or imaging system 170, such as the X-ray imaging system. Preferably, a scintillation plate 4710, such as a scintillating plastic is positioned behind the patient 2130 relative to the targeting/delivery system 140 elements. The charged particle beam system 100 as described has proven operation at up to and including 330 MeV, which is sufficient to send protons through the body and into contact with the scintillation material. The intensity or count of protons hitting the plate as a function of position is used to create an image. The patient 2130 is rotated 2117 about the y-axis and a new image is collected. Preferably, a new image is collected with about every one degree of rotation of the patient resulting in about 360 images that are combined into a tomogram using tomographic reconstruction software. The tomographic reconstruction software uses overlapping rotationally varied images in the reconstruction. Optionally, a new image is collected at about every 2, 3, 4, 5, 10, 15, 30, or 45 degrees of rotation of the patient. In one embodiment, a tomogram or an individual tomogram section image is collected at about the same time as cancer therapy occurs using the charged particle beam system. For example, an tomogram is collected and cancer therapy is subsequently performed: without the patient moving from the positioning systems, such as the above described semi-vertical partial immobilization system 3300, the sitting partial immobilization system 3400, or the a laying position 3500. In a second example, an individual tomogram slice is collected using a first cycle of the accelerator 130 and using a following cycle of the accelerator 130, the tumor 2120 is irradiated, such as within about 1, 2, 5, 10, 15 or 30 seconds. In a third case, about 2, 3, 4, or 5 tomogram slices are collected using 1, 2, 3, 4, or more rotation positions of the patient 2130 within about 5, 10, 15, 30, or 60 seconds of subsequent tumor irradiation therapy. In another embodiment, the independent control of the tomographic imaging process and X-ray collection process allows simultaneous single and/or multi-field collection of X-ray images and tomographic images easing interpretation of multiple images. Indeed, the X-ray and tomographic images are optionally overlaid to from a hybrid X-ray/proton beam tomographic image as the patient is optionally in the same position for each image. In still another embodiment, the tomogram is collected with the patient 2130 in the about the same position as when the patient's tumor is treated using subsequent irradiation therapy. For some tumors, the patient being positioned in the same upright or semi-upright position allows the tumor 2120 to be separated from surrounding organs or tissue of the patient 2130 better than in a laying position. Positioning of the scintillation plate 4710 behind the patient 2130 allows the tomographic imaging to occur while the patient is in the same upright or semi-upright position. The use of common elements in the tomographic imaging and in the charged particle cancer therapy allows benefits of the cancer therapy, described supra, to optionally be used with the tomographic imaging, such as proton beam x-axis control, proton beam y-axis control, control of proton beam energy, control of proton beam intensity, timing control of beam delivery to the patient, rotation control of the patient, and control of patient translation all in a raster beam mode of proton energy delivery. In yet still another embodiment, initially a three-dimensional tomographic proton based reference image is collected, such as with hundreds of individual rotation images of the tumor 2120 and patient 2130. Subsequently, just prior to proton treatment of the cancer, just a few 2-dimensional control tomographic images of the patient are collected, such as with a stationary patient or at just a few rotation positions, such as an image straight on to the patient, with the patient rotated about 45 degrees each way, and/or the patient rotated about 90 degrees each way about the y-axis. The individual control images are compared with the 3-dimensional reference image. An adaptive proton therapy is subsequently performed where: (1) the proton cancer therapy is not used for a given position based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images and/or (2) the proton cancer therapy is modified in real time based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images System Integration Any of the systems and/or elements described herein are optionally integrated together and/or are optionally integrated with known systems. Treatment Delivery Control System Referring now to FIG. 48, a centralized charged particle treatment system 4800 is illustrated. Generally, once a charged particle therapy plan is devised, a central control system or treatment delivery control system 112 is used to control sub-systems while reducing and/or eliminating direct communication between major subsystems. Generally, the treatment delivery control system 112 is used to directly control multiple subsystems of the cancer therapy system without direct communication between selected subsystems, which enhances safety, simplifies quality assurance and quality control, and facilitates programming. For example, the treatment delivery control system 112 directly controls one or more of: an imaging system, a positioning system, an injection system, a radio-frequency quadrupole system, a linear accelerator, a ring accelerator or synchrotron, an extraction system, a beam line, an irradiation nozzle, a gantry, a display system, a targeting system, and a verification system. Generally, the control system integrates subsystems and/or integrates output of one or more of the above described cancer therapy system elements with inputs of one or more of the above described cancer therapy system elements. Still referring to FIG. 48, an example of the centralized charged particle treatment system 4800 is provided. Initially, a doctor, such as an oncologist, prescribes 4810 or recommends tumor therapy using charged particles. Subsequently, treatment planning 4820 is initiated and output of the treatment planning step 4820 is sent to an oncology information system 4830 and/or is directly sent to the treatment delivery system 112, which is an example of the main controller 110. Still referring to FIG. 48, the treatment planning step 4820 is further described. Generally, radiation treatment planning is a process where a team of oncologist, radiation therapists, medical physicists, and/or medical dosimetrists plan appropriate charged particle treatment of a cancer in a patient. Typically, one or more imaging systems 170 are used to image the tumor and/or the patient, described infra. Planning is optionally: (1) forward planning and/or (2) inverse planning. Cancer therapy plans are optionally assessed with the aid of a dose-volume histogram, which allows the clinician to evaluate the uniformity of the dose to the tumor and surrounding healthy structures. Typically, treatment planning is almost entirely computer based using patient computed tomography data sets using multimodality image matching, image coregistration, or fusion. Forward Planning In forward planning, a treatment oncologist places beams into a radiotherapy treatment planning system including: how many radiation beams to use and which angles to deliver each of the beams from. This type of planning is used for relatively simple cases where the tumor has a simple shape and is not near any critical organs. Inverse Planning In inverse planning, a radiation oncologist defines a patient's critical organs and tumor and gives target doses and importance factors for each. Subsequently, an optimization program is run to find the treatment plan which best matches all of the input criteria. Oncology Information System Still referring to FIG. 48, the oncology information system 4830 is further described. Generally, the oncology information system 4830 is one or more of: (1) an oncology-specific electronic medical record, which manages clinical, financial, and administrative processes in medical, radiation, and surgical oncology departments; (2) a comprehensive information and image management system; and (3) a complete patient information management system that centralizes patient data; and (4) a treatment plan provided to the charged particle beam system 100, main controller 110, and/or the treatment delivery control system 112. Generally, the oncology information system 4830 interfaces with commercial charged particle treatment systems. Safety System/Treatment Delivery Control System Still referring to FIG. 48, the treatment delivery control system 112 is further described. Generally, the treatment delivery control system 112 receives treatment input, such as a charged particle cancer treatment plan from the treatment planning step 4820 and/or from the oncology information system 4830 and uses the treatment input and/or treatment plan to control one or more subsystems of the charged particle beam system 100. The treatment delivery control system 112 is an example of the main controller 110, where the treatment delivery control system receives subsystem input from a first subsystem of the charged particle beam system 100 and provides to a second subsystem of the charged particle beam system 100: (1) the received subsystem input directly, (2) a processed version of the received subsystem input, and/or (3) a command, such as used to fulfill requisites of the treatment planning step 4820 or direction of the oncology information system 4830. Generally, most or all of the communication between subsystems of the charged particle beam system 100 go to and from the treatment delivery control system 112 and not directly to another subsystem of the charged particle beam system 100. Use of a logically centralized treatment delivery control system has many benefits, including: (1) a single centralized code to maintain, debug, secure, update, and to perform checks on, such as quality assurance and quality control checks; (2) a controlled logical flow of information between subsystems; (3) an ability to replace a subsystem with only one interfacing code revision; (4) room security; (5) software access control; (6) a single centralized control for safety monitoring; and (7) that the centralized code results in an integrated safety system 4840 encompassing a majority or all of the subsystems of the charged particle beam system 100. Examples of subsystems of the charged particle cancer therapy system 100 include: a radio frequency quadrupole 4850, a radio frequency quadrupole linear accelerator, the injection system 120, the synchrotron 130, the accelerator system 132, the extraction system 134, any controllable or monitorable element of the beam line 268, the targeting/delivery system 140, the nozzle 146, a gantry 4860 or an element of the gantry 4860, the patient interface module 150, a patient positioner 152, the display system 160, the imaging system 170, a patient position verification system 172, any element described supra, and/or any subsystem element. Still yet another embodiment includes any combination and/or permutation of any of the elements described herein. The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. In the foregoing description, the invention has been described with reference to specific exemplary embodiments; however, it will be appreciated that various modifications and changes may be made without departing from the scope of the present invention as set forth herein. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the generic embodiments described herein and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present invention and are accordingly not limited to the specific configuration recited in the specific examples. Herein, any integer number is optionally at least the integer number or less than the integer number. Herein, any integer number is optionally the number plus or minus 1, 2, 5, 10, or 20 percent of the integer number. Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below.
051715147	summary	BACKGROUND This invention generally relates to apparatus for sealing conduits and more particularly relates to a nozzle dam having a unitary plug for sealing the primary nozzles of a nuclear steam generator. Before discussing the current state of the art, it is instructive first to briefly describe the structure and operation of a typical nuclear steam generator. In this regard, a typical nuclear steam generator generally comprises a vertically oriented shell and a plurality of inverted U-shaped heat transfer tubes disposed in the shell. Pressurized radioactive primary fluid (e.g., water), which is heated by the core of a nuclear reactor, flows through the tubes as nonradioactive secondary fluid (i.e., water) of lower temperature circulates around the tubes. The steam generator further comprises a lower plenum defining an inlet plenum chamber and an outlet plenum chamber. A first leg of each inverted U-shaped heat transfer tube is in fluid communication with the inlet plenum chamber and the second leg of each inverted U-shaped heat transfer tube is in fluid communication with the outlet plenum chamber. Attached to the lower plenum and in fluid communication with the inlet plenum chamber is an inlet primary nozzle for delivering the primary fluid into the inlet plenum chamber. Moreover, attached to the lower plenum and in fluid communication with the outlet plenum chamber is an outlet primary nozzle for allowing the primary fluid to exit the outlet plenum chamber and thus exit the steam generator in the manner disclosed hereinbelow. In addition, the steam generator also includes a plurality of relatively small diameter manway openings in the lower plenum for allowing access to the inlet and outlet plenum chambers so that maintenance can be performed in the steam generator. In this typical nuclear steam generator, each manway opening has a diameter substantially less than the inside diameters of the inlet and outlet primary nozzles. During operation of the steam generator, the primary fluid, which is heated by the nuclear reactor core, flows from the nuclear reactor core, through the inlet primary nozzle and into the inlet plenum chamber. The primary fluid then flows into the first leg of each heat transfer tube, out the second leg of each heat transfer tube and then into the outlet plenum chamber, whereupon it exits the outlet primary nozzle. Moreover, as the primary fluid exits the outlet primary nozzle, it is returned to the nuclear reactor core to be reheated. It will be appreciated that as the primary fluid flows through the heat transfer tubes, heat is transferred from the primary fluid to the secondary fluid for producing steam in a manner well known in the art of nuclear-powered electricity production. Such a nuclear steam generator is more fully disclosed in U.S. Pat. No. 4,079,701 entitled "Steam Generator Sludge Removal System" issued Mar. 21, 1978 to Robert A. Hickman et al. Periodically, it is necessary to shut down the nuclear reactor core for refueling. At that time, it is also advantageous to perform maintenance on the steam generator. Such maintenance, for example, may be to plug and/or sleeve potentially degraded steam generator tubes or to decontaminate the steam generator. During maintenance activities, the reactor is partially drained of primary fluid to a level that is below the elevation of the inlet and outlet primary nozzles of the steam generator. However, it should be appreciated that the nuclear reactor should never be drained to a level that uncovers the reactor core. This process of partially draining the reactor also drains the heat transfer tubes and the inlet and outlet plenum chambers. After the heat transfer tubes and the inlet and outlet plenum chambers are drained of primary fluid, nozzle dams are inserted through the relatively small diameter manways and installed in the inlet and outlet primary nozzles to block the nozzles. Once these dams are in place, the nuclear reactor and the refueling cavity can then be refilled with primary fluid for the refueling operation, without interfering with maintenance activities being performed in the steam generator lower plenum because the nozzle dams prevent radioactive primary fluid from rising into the lower plenum of the steam generator. Also, once the nozzle dams are installed, the steam generator can be subjected to a chemical decontamination procedure without contaminating the nuclear reactor with contaminants removed during the decontamination of the steam generator because the inlet and outlet primary nozzles are blocked by the nozzle dams. Moreover, it is cost advantageous to simultaneously perform steam generator maintenance while the reactor core is being refueled rather than performing these activities in seriatim. This is true because it is necessary to shut down the reactor core during refueling or during steam generator maintenance. Of course, revenue-producing electricity is not generated while the reactor core is shut down. Each day the reactor core is shut down results in approximately $200,000 in lost revenue. Therefore, simultaneously performing reactor refueling and steam generator maintenance activities reduces the time the reactor core is shut down, thereby recapturing a portion of the approximately $200,000 each day in revenue that would otherwise be lost. As stated hereinabove, the manway openings are typically substantially smaller than the inside diameter of the primary nozzles. Therefore, it has been necessary in the art to use foldable nozzle dams that can be folded to fit through the relatively small diameter manways and then unfolded to be disposed in the primary nozzles. The elastomeric seals of such nozzle dams are subjected to stresses, such as bending stresses, as the nozzle dams are folded and unfolded. Repeated folding and unfolding of the nozzle dam may increase the risk that the seals will loose their sealing ability over time after being subjected to these stresses as the nozzle dam is repeatedly folded and unfolded. Steam generator nozzle dams are known. One such nozzle dam is disclosed in U.S. Pat. No. 4,637,588 entitled "Non-Bolted Ringless Nozzle Dam" issued Jan. 20, 1987 in the name of John J. Wilhelm et al. and assigned to the assignee of the present invention. This patent discloses a nozzle dam having one or more seal assemblies, each including a foldable circular seal plate encircled with an inflatable seal which is disposable in frictional engagement with the nozzle wall. It is a significant aspect of the Wilhelm et al. device that the seal plate be foldable because the nozzle dam must fit through the steam generator manway which has a diameter substantially less than that of the nozzle into which the nozzle dam will fit. Another nozzle dam is disclosed in U.S. Pat. No. 4,671,326 entitled "Dual Seal Nozzle Dam and Alignment Means Therefor" issued Jun. 9, 1987 in the name of John J. Wilhelm et al. and assigned to the assignee of the present invention. This patent discloses a seal assembly including a foldable circular seal plate having a center section hingedly connected to two side sections. The seal plate is foldable for inserting the nozzle dam through the relatively small diameter steam generator manway. This patent also provides that a worker is present in the steam generator to unfold and insert the nozzle dam into the primary nozzle. Therefore, a problem in the art has been to provide a nozzle dam that need not be folded and unfolded, so that the sealing ability of the seals attached to the nozzle dam are not compromised. Another problem in the art has been to provide a nozzle dam having a unitary plug that is remotely installable so that maintenance personnel need not be present in the radioactive environment of the steam generator to manually insert the nozzle dam in the primary nozzles. Thus, although the above recited patents may disclose nozzle dam devices, these patents do not appear to disclose a nozzle dam having a unitary plug capable of being remotely inserted through a relatively small diameter steam generator manway without the necessity of the nozzle dam and plug being foldable and unfoldable. Therefore, what is needed is a nozzle dam having a unitary plug for sealing the primary nozzles of a nuclear steam generator, the unitary plug capable of being remotely inserted through a relatively small diameter steam generator manway without the necessity of the nozzle dam and plug being foldable and unfoldable in order to insert it through the manway opening. SUMMARY Disclosed herein is a nozzle dam having a unitary plug for sealing the primary nozzles of a nuclear steam generator. In the preferred embodiment, the nozzle dam includes a bracket having an outside surface for matingly engaging the inside surface of the nozzle. The bracket, which preferably will have been previously attached to the inside surface of the nozzle, such as during manufacture of the steam generator, also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A unitary plug is associated with each opening of the bracket and is matingly disposed in each associated opening for sealably plugging each opening. Each plug includes a plurality of slidable elongated arms operable to engage the slots of the bracket for connecting the plug to the bracket. The plug further includes a first plate disposed in each opening of the bracket, the first plate having a threaded longitudinal first bore and a plurality of substantially smooth transverse channels therethrough, each channel capable of matingly slidably receiving an associated arm belonging to each plug. The plug also includes a second plate mounted on the top surface of the bracket and disposed coaxially adjacent the first plate. The second plate has a threaded second bore longitudinally therethrough. A rotatable threaded shaft extends through the threaded bores of the first and second plates for connecting the first and second plates together. More specifically, the shaft has a first threaded portion for threadably engaging the threaded first bore of the first plate and a second threaded portion for threadably engaging the threaded second bore of the second plate. The shaft also has a third threaded portion intermediate the first threaded portion and the second threaded portion of the shaft. The threads of the first bore of the first plate are "finer" than the threads of the second bore of the second plate, so that the first and second plates move as the shaft is turned. That is, the threads of the first threaded portion and the second threaded portion are in the same direction but have a different pitch, so that as the shaft is rotated the first plate and the second plate move closer together or further apart, depending on the direction of rotation of the shaft. The threads of the third threaded portion of the shaft are disposed in a direction opposite that of the first threaded portion and the second threaded portion of the shaft for reasons provided immediately hereinbelow. The plug also includes a wing nut having a threaded bore longitudinally therethrough for threadably engaging the third threaded portion of the shaft. The wing nut also has a hole of a predetermined contour transversely therethrough defining a cam surface. Each of the slidable arms is slidably disposed in each associated channel of the first plate, each arm having a first end portion and a second end portion, the second end portion sized to engage the transverse slot of the bracket. A rounded cam is integrally attached to the first end portion of the arm for slidably engaging the contour of the cam surface defined by the hole of the wing nut. As the shaft is rotated, the wing nut threadably traverses along the shaft because the threads of the third threaded portion of the shaft are oppositely disposed with respect to the threads of the first and second threaded portions of the shaft. As the wing nut threadably traverses along the shaft, the contoured cam surface of the wing nut slidably engages the cam, thus causing the arm to slide in the channel because the cam is attached to the arm. As the arm slides in the channel, the second end portion of each arm slidably engages its associated slot for connecting the plug to the bracket. An object of the present invention is to provide a remotely installable apparatus for sealing a conduit, such as the primary nozzles of a nuclear steam generator. Another object of the present invention is to provide a nozzle dam having a unitary plug that need not be folded and unfolded in order to pass it through the relatively small diameter manway of the nuclear steam generator. A feature of the present invention is that the unitary plug is sized to pass through the relatively small diameter manway of the nuclear steam generator. Another feature of the present invention is the provision of a seal attached to the plug in such a manner that the seal is not subjected to substantial stresses, such as bending stresses. An advantage of the present invention is that it is not necessary to fold or to disassemble the plug in order to pass the plug through the relatively small diameter manway and thereafter dispose personnel in the radioactive environment of the steam generator to unfold or reassemble the plug to install the plug in the primary nozzle. Another advantage of the present invention is that, because of its unitary construction, the plug belonging to the nozzle dam is easily remotely installable in the primary nozzle of the steam generator, thus eliminating the radiation dose to maintenance personnel otherwise required to enter the steam generator to unfold or reassemble the plug in order to install the plug in the primary nozzle.
	summary
046408118	abstract	Magnetic actuators with dogs for positioning regulating rods in a nuclear reactor. The dogs (2) for lifting and/or holding the control shaft (1) are provided with at least two teeth (4) separated by a distance equalling that separating two successive grooves (3) of the shaft (1).
	description	Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components. As shown in the accompanying drawings, a lips-type multi-purposed spacer grid 50 according to the present invention receives and supports a plurality of elongated nuclear fuel rods 8 at positions spaced at regular intervals in a nuclear fuel assembly, and comprises a plurality of two types of inner strips 12 and 13. The two types of inner strips 12 and 13 intersect each other at right angles in accordance with a designed array, thus forming the spacer grid 50 with a plurality of four-walled unit cells for receiving and supporting the elongated nuclear fuel rods 8, as shown in FIGS. 2, 4a and 4b. Each of the inner strips 12 and 13 is fabricated, as shown in FIGS. 3a and 3b, by integrating a plurality of unit strip parts 45 into a linear strip, and each of the unit strip parts 45 is comprised of a water strider-type spring 16, an upper dimple 15 and a lower dimple 17, as will be described later herein. The inner strips 12 and 13 each have a plurality of notches at the junctions of the unit strip parts 45 such that each notch having a predetermined length vertically extends downward or upward. In the nuclear fuel assembly, one fuel rod 8 is received and supported within one cell. As shown in FIGS. 5 to 7d, each of the unit strip parts 45 constituting the inner strips 12 and 13 is comprised of a frame used as a support frame of the unit strip part 45, the water strider-type spring 16 formed in an opening defined at the middle part of the frame, and the upper and lower dimples 15 and 17 provided at the upper and lower parts of the frame, respectively. That is, the upper and lower dimples 15 and 17 are formed at positions above and under the water strider-type spring 16 in each unit strip part 45. The unit strip part 45 also has a mixing blade 14. The mixing blade 14 extends upward to a predetermined length from a side of the upper edge of the upper dimple 15, as best seen in FIG. 5. In the spacer grid 50 according to the present invention, the spring 16 has a shape similar to the profile of a water strider that is an aquatic insect of the family Gerridae, having six slender legs fringed with hairs, enabling the insect to dart about on the surface of water. Of the six legs of the water strider, four long legs except for two relatively short forelegs extend from the body in diagonal directions in a manner similar to that of the spring 16, so the spring 16 is a so-called xe2x80x9cwater strider-type springxe2x80x9d. The frame of each unit strip part 45 is comprised of two vertical support columns 40 and two horizontal support beams 25. The two support columns 40 are vertically disposed in parallel while being spaced apart from each other at a predetermined interval. The two horizontal support beams 25 horizontally extend between the two columns 40 at vertically symmetrical upper and lower positions, thus connecting the two columns 40 to each other and defining a rectangular middle opening between the beams 25 and the columns 40. An upper opening which is open upward is defined between the two columns 40 and the upper beam 25, and a lower opening which is open downward is defined between the two columns 40 and the lower beam 25. The water strider-type spring 16 is formed in the rectangular middle opening of the frame. As shown in FIGS. 6a to 6c, the water strider-type spring 16 is comprised of an equiangular curved part 23, two side extensions 36 and 37, and four spring legs 28. The equiangular curved part 23 is axially formed along the central axis of the spring 16, and has a predetermined width while being curved within the direction of the width at a radius of curvature allowing the equiangular curved part 23 of the spring 16 to come into surface contact with the cladding of a fuel rod 8. The two side extensions 36 and 37 extend outward to a predetermined width while being bent at a predetermined angle in opposite directions from both sides of the equiangular curved part 23. The four spring legs 28 diagonally extend from upper and lower comers of the two side extensions 36 and 37. The four spring legs 28 are connected to the inside edges of the frame at the four corners of the rectangular middle opening of the frame. The four spring legs 28 are thus integrated with the frame of the unit strip part 45 at four points, so that the water strider-type spring 16 has a four point support structure in which the spring 16 supports a fuel rod at the four points. The spring 16 is also projected in a direction from a vertical surface formed by the frame. The upper and lower dimples 15 and 17 are formed at positions above and under the water strider-type spring 16 in each unit strip part 45. As shown in FIGS. 7a to 8b, each of the upper and lower dimples 15 and 17 is comprised of a curved dimple part 20 and two side dimple extensions 21. The curved dimple part 20 is axially formed along the central axis of each dimple 15, 17, and has a predetermined width while being curved within the direction of the width at a radius of curvature allowing the curved dimple part 20 to come into surface contact with the cladding of the fuel rod 8. The two side dimple extensions 21 extend outward in opposite directions from both sides of the curved dimple part 20 to a predetermined width is while being curved at a predetermined angle. The upper dimple 15 is curved along the lower edge thereof to form an arc-shaped lower edge 32, while the lower dimple 17 is curved along the upper edge thereof to form an arc-shaped upper edge 31. The upper and lower dimples 15 and 17 are also projected from the vertical surface formed by the frame in a direction opposed to the projecting direction of the water strider-type spring 16. The radius of curvature of the equiangular curved part 23 of the water strider-type spring 16 is determined to be slightly larger than that of the cladding of each fuel rod 8, so that the equiangular curved part 23 comes into close surface contact with the cladding of the fuel rod 8 and soundly supports the fuel rod 8 even when the fuel rod 8 vibrates or is impacted by external force. That is, the radius of curvature of the equiangular curved part 23 is designed to be slightly larger than that of the cladding of each fuel rod 8 before the fuel rod 8 is installed in a unit cell of the spacer grid. However, after the fuel rod 8 is installed in the unit cell of the spacer grid, the radius of curvature of the equiangular curved part 23 becomes equal to that of the cladding because the cladding pushes the spring 16 in a direction opposed to the projecting direction of the spring 16. An axial opening 29 is formed along the central axis of the equiangular curved part 23 to have a slender appearance, so that coolant is completely collected in the gap between the cladding of the fuel rod 8 and the equiangular curved part 23. Therefore, it is possible to prevent disturbance of heat transfer at a part of the cladding-due to the coolant remaining at the gap between the cladding and the equiangular curved part 23, so that the spacer grid does not cause nucleate boiling at the claddings of fuel rods 8. The four spring legs 28 of the water strider-type spring 16 may have bent parts 24 at which the spring legs 28 are bent in a direction opposed to the bent direction of the two side extensions 36 and 37. In such a case, the bent parts 24 of the spring legs 28 are projected from the vertical surface formed by the frame in a direction opposed to the projecting direction of the equiangular curved part 23. In addition, it is possible to control the fuel rod support force of the water strider-type spring 16 by adjusting the bent angle of the bent parts 24. The upper and lower edges of the water strider-type spring 16 are curved to form arc-shaped edges 38 which are symmetrical with respect to a horizontal axis of the spring 16. That is, the upper edge of the spring 16, formed by the upper edges of the equiangular curved part 23, the two side extensions 36 and 37 and the two upper spring legs 28, is downwardly curved to form an arc-shaped edge. In the same manner, the lower edge of the spring 16, formed by the lower edges of the equiangular curved part 23, the two side extensions 36 and 37 and the two lower spring legs 28, is upwardly curved to form an arc-shaped edge. The arc-shaped upper and lower edges of the water strider-type spring 16 are symmetrical with respect to the horizontal axis of the spring 16. Therefore, when the spacer grid of the present invention fabricated by the intersecting inner strips 12 and 13 is sectioned along a horizontal direction as shown in FIG. 4b, each of the water strider-type springs 16 is viewed in the form of a lower lip, while each of the upper and lower dimples 15 and 17 is viewed in the form of an upper lip. In each unit strip part 45 of the spacer grid, the water strider-type spring 16 is projected in a direction opposed to that of the upper and lower dimples 15 and 17, so that the spring 16 and the dimples 12 and 13 of each unit strip part 45 support different fuel rods 8, separately. In addition, when the spring 16 and the dimples 12 and 13 of each unit strip part 45 are viewed from the top or the bottom of the spacer grid, they form a pair of lips. As shown in FIGS. 9a to 9d, the mixing blade 14 extends upward to a predetermined length from the upper edge of one side dimple extension 21 of the upper dimple 15 while being smoothly curved in the same direction as the projecting direction of the water strider-type spring 16. The mixing blade 14 thus has a spoon-shaped configuration which is concave at a side surface thereof facing the fuel rod 8. It is preferable to determine the bent angle of the mixing blade 14 relative to a vertical surface of the unit strip part to 90xc2x0 or less. That is, the mixing blade 14 is curved such that an acute angle is formed between a normal line at the uppermost end of the mixing blade 14 and an axial line of the side dimple extension 21 of the upper dimple 15. In addition, the upper edge of each mixing blade 14 is placed along a circle which has a radius larger than that of the cladding of a fuel rod 8, as shown in FIG. 9b, so that the mixing blades 14 do not scratch or damage the cladding of the fuel rod 8 during a process of installing fuel rods 8 in the spacer grid while producing a nuclear fuel assembly. In order to space the mixing blades 14 apart from the cladding of the fuel rod 8, the upper edges of the mixing blades 14 are designed such that they are placed along a circle having a diameter larger than that of the cladding. As shown in FIGS. 4a and 4b, the lips-type multi-purposed spacer grid 50 according to the present invention is fabricated by the two types of inner strips 12 and 13 which are each comprised of a plurality of unit strip parts 45 integrated into a linear strip, and which intersect each other at right angles to form a plurality of four-walled unit cells in the spacer grid 50 for receiving and supporting the elongated nuclear fuel rods 8 such that one fuel rod 8 is received and supported within one cell. The water strider-type spring 16 of each unit strip part 45 is projected from a vertical surface formed by the frame of the unit strip part 45 in a direction opposed to the projecting direction of the upper and lower dimples 15 and 17. Therefore, within each four-walled unit cell of the spacer grid 50 defined by four unit strip parts 45, the two water strider-type springs 16 of two neighboring unit strip parts 45 meeting each other at a right angle are projected toward the center of the unit cell, and the upper and lower dimples 15 and 17 of the remaining two unit strip parts 45 are projected toward the center of the unit cell. The fuel rod 8, installed within the four-walled unit cell of the spacer grid 50, is thus supported at six points by the two springs 16 and the four dimples 15 and 17. In addition, the mixing blade 14 of each unit strip part 45 extends upward from the upper dimple 15 while being smoothly curved in the same direction as that of the water strider-type spring 16 of the unit strip part 45. Therefore, the mixing blades 14 of unit strip parts 45,are directed toward fuel rods 8 installed in neighboring unit cells. When viewing the spacer grid 50 of the present invention from the top as shown in FIG. 4a, the upper dimples 15 and the water strider-type springs 16 support the fuel rods 8 while being curved at their fuel rod contact surfaces at the same radius of curvature as that of the claddings of the fuel rods 8, and the mixing blades 14 extending from the upper dimples 15 are outwardly curved to be directed over neighboring unit cells. When viewing the spacer grid 50 from the bottom as shown in FIG. 4b, the lower dimples 17 and the: water strider-type springs 16 support the fuel rods 8 while being curved at their fuel rod contact surfaces at the same radius of curvature as that of the claddings of the fuel rods 8. FIGS. 9a and 9b show a four-walled unit cell 18 of the spacer grid according to the present invention, with a fuel rod 8 supported within the cell 18. Particularly, these drawings show the surface contact between the fuel rod 8 and the water strider-type springs 16 and the upper and lower dimples 15 and 17 of unit strip parts 45 defining the four-walled unit cell 18. FIG. 9d shows currents of coolant guided by the mixing blades 14 of the intersecting strips 12 and 13. Due to the mixing blades 14, the spacer grid 50 forcibly mixes coolants flowing through the coolant passages of the spacer grid, thus enhancing the fuel rod cooling efficiency of the nuclear fuel assembly. Since the upper dimple 15 has the arc-shaped lower edge 32, and the lower dimple 17 has the arc-shaped upper edge 31, it is possible to reduce pressure loss inside the spacer grid 50. In addition, the spacer grid 50 of the present invention does not have any horizontal support beam at a position under the lower dimple 17, different from conventional spacer grids, so that the inventive spacer grid 50 effectively removes impurities from coolant when the coolant having the impurities flows into the spacer grid 50 through the lower end of the spacer grid 50. The equiangular curved part 23 of each water strider-type spring 16 is axially formed along the central axis of the spring 16 such that the curved part 23 has a substantial length. Therefore, the fuel rod support surface of the springs 16 is enlarged, and the fuel rod support force of the springs 16 is increased. Soundness of the spacer grid 50 supporting the fuel rods 8 within a nuclear fuel assembly is thus improved. Another advantage of the spacer grid 50 according to the present invention resides in that load, applied to the water strider-type spring 16 of each unit strip part 45 from a fuel rod 8 through the equiangular curved part 23, is effectively distributed to the entire structure of the unit strip parts 45 through the four spring legs 28. FIG. 10 shows an inner strip constituting a lips-type multi-purposed spacer grid for nuclear fuel assemblies according to a second embodiment of the present invention. As shown in the drawing, the water strider-type spring 16xe2x80x2 provided in each unit strip part of the inner strip constituting the spacer grid according to the second embodiment is designed such that the width of the axial opening formed along the central axis of the equiangular curved part 23 is enlarged to reduce the width of the two side extensions 36 and 37. The spacer grid according to the second embodiment of the present invention improves heat transfer efficiency thereof, thus more effectively transferring heat from the claddings of fuel rods to coolant. In this embodiment, the size of the axial opening of the equiangular curved part 23 may be adjusted in an effort to control the fuel rod support force of the water strider-type spring 16xe2x80x2, thus improving the fuel rod support force of the springs 16xe2x80x2 and soundness of the spacer grid supporting the fuel rods in a nuclear fuel assembly. FIGS. 11a and 11b show an inner strip according to a third embodiment of the present invention, and a lips-type multi-purposed spacer grid fabricated by intersecting the inner strips, respectively. As shown in the drawings, each unit strip part of the inner strip according to the third embodiment is designed such that two water strider-type springs 16xe2x80x3, each having a short equiangular curved part 23, two short side extensions 36 and 37, and four short spring legs 28, are formed at upper and lower portions inside the rectangular middle opening of the unit strip part. Therefore, a fuel rod 8, installed within a four-walled unit cell of the spacer grid, is supported at eight points by four water strider-type springs 16xe2x80x3 and four dimples, so that the spacer grid more stably supports the fuel rods inside a nuclear fuel assembly. In addition, even though one of the two springs 16xe2x80x3 of each unit strip part is broken by, for example, impurities, the remaining spring 16xe2x80x3 effectively supports the fuel rod, so that soundness of the spacer grid supporting the fuel rods is improved. As described above, the present invention provides a lips-type multi-purposed spacer grid for nuclear fuel assemblies. In the spacer grid of the present invention, fuel rods are in contact with dimples and water strider-type springs in an equiangular surface contact manner. The spacer grid thus soundly supports the fuel rods even when the fuel rods are excessively loaded in any direction due to a variation in operational conditions of a nuclear reactor. Particularly, the fuel rod support surface of the springs is enlarged, and the fuel rod support force of the springs is increased. Soundness of the spacer grid supporting the fuel rods within a nuclear fuel assembly is thus improved, and the spacer grid reduces possible fretting wear of the fuel rods due to hydraulic vibration of the fuel rods. The springs of the inventive spacer grid each have four spring legs designed in the form of four long slender legs of a water strider. In addition, the four legs of the water strider-type spring each have a bent part which appropriately controls the fuel rod support spring force of the water strider-type spring, and enlarges the allowable elastic range of the spring. The upper and lower edges of the water strider-type spring are curved to form arc-shaped edges which are symmetrical with respect to a horizontal axis of the spring. Due to the arc-shaped upper and lower edges of the water strider-type spring, the torsion applied to the spring from a fuel rod through the equiangular curved part is effectively distributed to the entire structure of the unit strip part, so that the spacer grid effectively supports the fuel rods during an operation of a nuclear reactor. An axial opening is formed in the equiangular curved part of the water strider-type spring, so that it is possible to prevent disturbance of heat transfer at a part of the cladding due to coolant remaining at a gap between the cladding and the equiangular curved part. Therefore, the spacer grid does not cause nucleate boiling at the claddings of the fuel rods. It is also possible to control the fuel rod support spring force of the spacer grid to a desired level by appropriately changing the size of the axial opening formed at the equiangular curved part of the water strider-type spring. It is thus not necessary to impose excessive force on the fuel rods when installing or removing the fuel rods in or from the spacer grid, so that the claddings of the fuel rods are less likely to be scratched or damaged by the springs of the spacer grid. The claddings of the fuel rods are thus prevented from corrosion caused by such scratched or damaged parts. This results in an extension of life spans of the fuel rods. In addition, a mixing blade extends upward from the upper edge of an upper dimple while being smoothly curved to have a spoon-shaped configuration, so that the mixing blade changes the axial flow of coolant to a lateral flow within each unit four-walled cell of the spacer grid, thus effectively mixing the coolant within the spacer grid. Since the upper dimple has an arc-shaped lower edge, and the lower dimple has an arc-shaped upper edge, it is possible to reduce pressure loss inside the spacer grid. In addition, the flow direction of coolant flowed in from at the lower end of the spacer grid is changed, and the debris of coolant is guided to the gaps between the dimples and the water strider-type springs of the spacer grid, so that debris are effectively captured at the gaps. The spacer grid thus minimizes damage to the fuel rods due to such debris. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
	abstract	An auxiliary wedge positioning apparatus/assembly 100 for use in a nuclear reactor pressure vessel 12 having riser piping 44 and 144 and a jet pump assembly 46 and 120, the apparatus 100 having a combination slide wedge 105 and spring 103 mounted on a restraint bracket body 102 having a transverse rail 110 with end gull-wing hooked protrusions 111 with sections 150, 152, 156 and wing stability attachment 155, the slide wedge used for placement between the riser piping 44 and 144 and jet pump assembly 46 and 120 to control vibrations during operation of the reactor vessel 12.
	description	This application claims the benefit of Korean Patent Application No. 10-2007-0050506, filed on May 23, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 1. Field of the Invention The present invention relates to a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt which prevents a shutdown, due to a crack, of a heat exchanger and a steam generator in the nuclear reactor system using the liquid metal and molten salt by early monitoring and reporting of the crack of the heat exchanger or the steam generator. 2. Description of Related Art In nuclear power generation, materials with a nucleus possessing tremendous energy, such as Uranium, are used. Specifically, in nuclear power generation, tremendous energy, generated when atomic nucleus is fissioned or fused, is slowly converted into electric power. In this instance, various types of liquid metal reactors such as a pressurized water reactor (PWR), a heavy water reactor, a fast reactor, and the like are used to slowly generate a great amount of energy. Currently, liquid metal reactors such as a sodium cooled fast reactor (SFR) using liquid metals and molten salts, for example, liquid sodium, as a coolant is mainly used. In this instance, liquid metals and molten salts are excellent in heat transfer and do not decelerate neutrons. However, in a conventional art, nuclear reactor systems using liquid metals and molten salts have safety problems. In steam generators or heat exchangers of nuclear reactor systems using liquid metals and molten salts, cracks in heat pipes may occur due to corrosions or thermal imbalance. Such cracks cause serious damage to heat pipe tubes of steam generators or heat exchangers. Accordingly, such damage of heat pipe tubes results in shutdowns of steam generators in nuclear reactor systems using liquid metals and molten salts, heat exchangers in nuclear reactor systems using liquid metals and molten salts, or nuclear reactors. Thus, a sensing method and system which may sense cracks early as described above is required. The present invention provides a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt which sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may help the steam generator or the heat exchanger to control the water leakage (steam leakage). The present invention also provides a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt which sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may prevent a shutdown of nuclear reactor. The present invention also provides a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt which sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may prevent a shutdown of the steam generator or the heat exchanger included in the nuclear reactor system using the liquid metal and molten salt. According to an aspect of the present invention, there is provided a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt, the method including: measuring an electrical conductivity of a first channel and a second channel of a heat-related device included in the nuclear reactor system using the liquid metal and the molten salt; calculating an identification value associated with the water leakage in the heat-related device using the measured electrical conductivity; and sensing the water leakage by comparing the calculated identification value and a predetermined reference value. In the present invention, the heat-related device may indicate a steam generator or a heat exchanger included in the nuclear reactor using the liquid metal and the molten salt, for example, a liquid metal reactor, a sodium cooled fast reactor, a nuclear transmutation, and the like. In the present specification, the steam generator or the heat exchanger included in the nuclear reactor using the liquid metal and the molten salt is described as an example of the heat-related device for convenience of description. The nuclear reactor using the liquid metal and the molten salt may cover all types of reactors using the liquid metal and the molten salt as a coolant, and may include a fast reactor, a nuclear transmutation, and the like. For example, the nuclear reactor may include a liquid metal reactor, a sodium cooled fast reactor, a nuclear transmutation, a pressurized water reactor, a heavy water reactor, and the like. The heat exchanger uses two types of heating media. In the heat exchanger, water (steam) may be used in a tube side, and the liquid metal and molten salt such as sodium may be used in a shell side. Conversely, in the heat exchanger, the water (steam) may be used in the shell side, and the liquid metal and molten salt such as the sodium may be used in the tube side. According to another aspect of the present invention, there is provided a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt, the method including: measuring a mass spectrum of a first channel and a second channel of a heat-related device included in the nuclear reactor system using the liquid metal and the molten salt; calculating an identification value associated with the water leakage in the heat-related device using the measured mass spectrum; and sensing the water leakage by comparing the calculated identification value and a predetermined reference value. According to still another aspect of the present invention, there is provided a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt, the method including: measuring an electrical conductivity and a mass spectrum of a first channel and a second channel of a heat-related device included in the nuclear reactor system using the liquid metal and the molten salt; calculating a first identification value associated with the water leakage in the heat-related device using the measured electrical conductivity; calculating a second identification value associated with the water leakage in the heat-related device using the measured mass spectrum; and sensing the water leakage by comparing a predetermined reference value and a summed identification value, the summed identification value being the sum of the first identification value and the second identification value. Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. FIG. 1 is a flowchart illustrating a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt according to an embodiment of the present invention. In operation S101, a system for early sensing of water leakage according to the present invention measures an electrical conductivity of a first channel and a second channel of a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and the molten salt. Specifically, in operation S101, the electrical conductivity of each of the first channel and the second channel is measured using an electrical conductivity sensor. The first channel includes outlet 1 and outlet 2 of the steam generator or the heat exchanger. Also, the second channel includes an inlet of the steam generator or the heat exchanger. Although it is described that the first channel includes two outlets, that is, the outlet 1 and the outlet 2, and the second channel includes one inlet in the present specification, a number of outlets or a number of inlets, included in the first channel and the second channel, respectively, may vary considering a system environment. Here, the measured electrical conductivity may be different in the inlet and the outlet of the steam generator or the heat exchanger depending on a chemical reaction of sodium and water, since development of sodium oxide occurs due to the chemical reaction of sodium and water when the sodium penetrates into the water (steam) at an early stage of a crack generation in a heat pipe of the steam generator or the heat exchanger. The sodium oxide generated by the chemical reaction fills the crack at the early stage of the crack generation. Then, the sodium oxide in the crack contacts with the water (steam) and dissolves in the water (steam). Also, after the crack occurs, the crack gradually grows, and the sodium oxide penetrates into the water (steam) along a wall of the crack. Also, concentrations of chemicals increase due to the dissolving of the sodium oxide in the water (steam), and thus an electrical conductivity and a mass spectrum increase. That is, the system for early sensing of water leakage measures the electrical conductivity of the outlet 1, the outlet 2, and the inlet to determine whether the crack of the steam generator or the heat exchanger occurs. Accordingly, the system for early sensing of water leakage may ascertain whether the sodium into the crack reacting with the water (steam) in the steam generator or the heat exchanger is penetrated. The steam generator or the heat exchanger may include an m number of outlets or an n number of inlets. In this instance, each of the m and the n is a natural number greater than 1. Although it is described that the two outlets and one inlet are included in the steam generator or the heat exchanger in the present specification, it will be apparent to those skilled in the related arts the present invention is not limited to the above-described embodiment. Also, the electrical conductivity may be replaced with a acidity (pH). The pH may be different in the inlet and the outlet due to the chemical reaction of the water (steam) and the sodium. In operation S102, the system for early sensing of water leakage performs a dilution correction or a temperature compensation with respect to the measured electrical conductivity. In operation S102, the dilution correction or the temperature compensation with respect to the measured electrical conductivity is performed considering a fact that the measured electrical conductivity is affected by a temperature and a dilution of the sodium when measured. Specifically, the system for early sensing of water leakage may correct the measured electrical conductivity to be consistent with a standard temperature or a standard dilution. Here, the standard temperature or the standard dilution is used as a standard for determining whether the water leaks. As an example of correcting the measured electrical conductivity, the standard temperature is set to ‘15 degrees Celsius’ and the standard dilution is set to ‘4%’. It is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a temperature when measuring the electrical conductivity is different from the standard temperature by ‘±1 degree’. Also, it is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a dilution when measuring the electrical conductivity is different from the standard dilution by ‘±1%’. When the temperature when measuring the electrical conductivity is ‘10 degrees Celsius’ and the dilution when measuring the electrical conductivity is ‘3%’, the system for early sensing of water leakage may correct the measured electrical conductivity to be consistent with the standard temperature or the standard dilution. Specifically, when the measured electrical conductivity is ‘15S’, a corrected electrical conductivity is ‘9S’ (9=15−5−1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. In operation S103, the system for early sensing of water leakage calculates a first difference value between an electrical conductivity of the outlet 1 and an electrical conductivity of the inlet, and calculates a second difference value between an electrical conductivity of the outlet 2 and the electrical conductivity of the inlet. In operation S1103, a difference between the electrical conductivity of each of the outlet 1, the outlet 2, and the inlet is ascertained using the measured electrical conductivity. Specifically, the system for early sensing of water leakage may calculate the difference between the electrical conductivity of the inlet and the electrical conductivity of the outlet 1 or the outlet 2. In this instance, the electrical conductivity is different depending on the chemical reaction of sodium and water. Accordingly, the system for early sensing of water leakage may determine whether the water (steam) leaks based on the difference. Here, the system for early sensing of water leakage may calculate the first difference value and the second difference value using a Wheatstone Bridge circuit. As an example of calculating of the first difference value and the second difference value, it is assumed that the electrical conductivity of the inlet is ‘10S’, the electrical conductivity of the outlet 1 is ‘15S’, and the electrical conductivity of the outlet 2 is ‘20S’. A first difference value ‘5’ (5=15−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 1. A second difference value ‘10’ (10=20−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 2. In operation S104, the system for early sensing of water leakage calculates an identification value by summing comparison values. In this instance, the comparison values are outputted by comparing a predetermined threshold value and each of the calculated first difference value and the calculated second difference value. In operation S104, the identification value, which may be compared to the predetermined reference value, that is, a standard for determining whether water leaks due to the crack, is calculated. As an example of calculating the identification value, it is assumed that the first difference value is ‘2’, the second difference value is ‘12’, and the threshold value is ‘5’. Here, when the first difference value or the second difference value is greater than the threshold value, the comparison values may correspond to the first difference value or the second difference value, or a logical value ‘1’. Also, when the first difference value or the second difference value is less than or equal to the threshold value, the comparison values may be ‘0’ or a logical value ‘0’. Since the first difference value is ‘2’ and the threshold value is ‘5’, a first comparison value, that is, a comparison result of the first difference value and the threshold value, is ‘0’ or the logical value ‘0’. Also, since the second difference value is ‘12’ and the threshold value is ‘5’, a second comparison value, that is, a comparison result of the second difference value and the threshold value, is ‘12’, that is, the second difference value, or the logical value ‘1’. Then, the system for early sensing of water leakage sums the first comparison value and the second comparison value, and thereby may calculate the identification value, that is, ‘12’ (12=0+12) or the logical value ‘1’ (1=1+0). In operation S105, the system for early sensing of water leakage senses water leakage by comparing the calculated identification value and a predetermined reference value. In operation S105, the system for early sensing of water leakage senses whether the water leaks by comparing the calculated identification value with the predetermined reference value which is a standard for determination with respect to whether the water leaks in the steam generator or the heat exchanger. Specifically, the system for early sensing of water leakage may determine whether the water leaks by comparing the predetermined reference value and the identification value calculated using the measured electrical conductivity. When the identification value is greater than the reference value, that is, ‘yes’ direction in FIG. 1, the system for early sensing of water leakage determines the water leaks, outputs the logical value ‘1’, and may perform a subsequent operation. Conversely, when the identification value is less than or equal to the reference value, that is, ‘no’ direction in FIG. 1, the system for early sensing of water leakage outputs the logical value ‘0’ and determines the water does not leak. As an example of comparing the identification value and the reference value, it is assumed that the identification value is ‘12’ and the reference value is ‘10’. Since the identification value is greater than the reference value, the system for early sensing of water leakage may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the identification value is ‘9’ and the reference value is ‘10’, since the identification value is less than or equal to the reference value, the system for early sensing of water leakage may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’. As another example of comparing the identification value and the reference value, it is assumed that the identification value is logical value ‘1’ and the reference value is the same as the logical value ‘0’. Since the identification value is greater than the reference value, the system for early sensing of water leakage may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the identification value is the same as the logical value ‘0’ and the reference value is the same as the logical value ‘0’, since the identification value is identical to the reference value, the system for early sensing of water leakage may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’. In operation S106, when the water leakage is sensed in the steam generator or the heat exchanger, the system for early sensing of water leakage raises a leakage alarm. In operation S106, when the water leakage in the steam generator or the heat exchanger is sensed, that is, the logical value ‘1’ is outputted in operation S105, the system for early sensing of water leakage reports the leakage to a person in charge of operating the system for early sensing of water leakage. Specifically, the system for early sensing of water leakage may inform the person of the situation using light, sound, video, characters, and the like. FIG. 2 is a flowchart illustrating a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt according to another embodiment of the present invention. As illustrated in FIG. 2, a system for early sensing of water leakage according to the other embodiment of the present invention measures a mass spectrum instead of an electrical conductivity. For this, the system for early sensing of water leakage uses a sampling port which measures the mass spectrum, instead of an electrical conductivity sensor which measures the electrical conductivity, of an inlet, an outlet 1, or an outlet 2 of a steam generator or a heat exchanger. When comparing the method of early sensing of water leakage according to the other embodiment of the present invention, that is, a mass spectrum measurement, with a method of early sensing of water leakage according to an embodiment of the present invention, that is, an electrical conductivity measurement, only methods used for measuring and objects of measurement are different. Thus, operations S201, S202, S203, S204, and S205 are analogous to operations S101, S102, S103, S104, and S105, respectively. in the related arts may fully understand the method of early sensing of water leakage according to the other embodiment of the present invention, that is, the mass spectrum measurement, based on the method of early sensing of water leakage according to the above embodiment of the present invention, that is, the electrical conductivity measurement. Thus, a more detailed description is omitted. FIG. 3 is a flowchart illustrating a method of early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt according to still another embodiment of the present invention. In operation S301, a system for early sensing of water leakage measures an electrical conductivity and a mass spectrum of a first channel and a second channel of a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and the molten salt. Specifically, the electrical conductivity and the mass spectrum each of the first channel and the second channel of the steam generator or the heat exchanger are measured. The first channel includes an outlet 1 and an outlet 2 of the steam generator or the heat exchanger, and the second channel includes an inlet of the steam generator or the heat exchanger. Accordingly, the system for early sensing of water leakage may measure the electrical conductivity and the mass spectrum of each of the outlet 1, the outlet 2, and the inlet of the steam generator or the heat exchanger. In operation S302, the system for early sensing of water leakage performs a dilution correction or a temperature compensation with respect to the measured electrical conductivity or mass spectrum. In operation S302, the dilution correction or the temperature compensation with respect to the measured electrical conductivity or mass spectrum is performed considering a fact that the measured electrical conductivity or mass spectrum is affected by a temperature and a dilution of sodium when measured. Specifically, the system for early sensing of water leakage may correct the measured electrical conductivity or mass spectrum to be consistent with a standard temperature or a standard dilution. Here, the standard temperature or the standard dilution is used to determine whether water leaks. As an example of correcting the measured electrical conductivity or mass spectrum, when measuring the electrical conductivity or mass spectrum, the standard temperature is set to ‘15 degrees Celsius’ and the standard dilution is set to ‘4%’. It is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a temperature when measuring the electrical conductivity is different from the standard temperature by ‘±1 degree’. Also, it is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a dilution when measuring the electrical conductivity is different from the standard dilution by ‘±1%’. Also, it is assumed that a correction method with respect to the mass spectrum is performed in the same way as the electrical conductivity. As an example, when the temperature when measuring the electrical conductivity or mass spectrum is ‘10 degrees Celsius’ and the dilution when measuring the electrical conductivity or mass spectrum is ‘3%’, the system for early sensing of water leakage may assume a measurement environment described above to be different from the standard temperature and the standard dilution, and correct the measured electrical conductivity or mass spectrum to be consistent with the standard temperature and the standard dilution. Specifically, when the measured electrical conductivity is ‘15S’, a corrected electrical conductivity is ‘9S’ (9=15-5-1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. Also, when the measured mass spectrum is ‘14’, a corrected mass spectrum is ‘8’ (8=14−5−1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. In operation S303, the system for early sensing of water leakage calculates a first difference value between the electrical conductivity of the outlet 1 and the electrical conductivity of the inlet, and calculates a second difference value between the electrical conductivity of the outlet 2 and the electrical conductivity of the inlet. Also, the system for early sensing of water leakage calculates a third difference value between the mass spectrum of the outlet 1 and the mass spectrum of the inlet, and calculates a fourth difference value between the mass spectrum of the outlet 2 and the mass spectrum of the inlet. In operation S303, a difference between the electrical conductivity and the mass spectrum of each of the outlet 1, the outlet 2, and the inlet is ascertained using the measured electrical conductivity and mass spectrum. Specifically, the system for early sensing of water leakage may calculate the difference between the electrical conductivity and the mass spectrum of the inlet and the electrical conductivity and the mass spectrum of the outlet 1 and the outlet 2, depending on a chemical reaction of sodium and water. Accordingly, the system for early sensing of water leakage may determine how significant a crack is based on the difference. Here, the system for early sensing of water leakage may calculate the first difference value, the second difference value, the third difference value, and the fourth difference value using a Wheatstone Bridge circuit. As an example of calculating of the first difference value, the second difference value, the third difference value, and the fourth difference value, it is assumed that the electrical conductivity of the inlet is ‘10S’, the electrical conductivity of the outlet 1 is ‘15S’, and the electrical conductivity of the outlet 2 is ‘20S’. Also, it is assumed that the mass spectrum of the inlet is ‘10’, the mass spectrum of the outlet 1 is ‘15’, and the mass spectrum of the outlet 2 is ‘20’. Here, a first difference value ‘5’ (5=15−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 1. A second difference value ‘10’ (10=20−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 2. Also, a third difference value ‘5’ (5=15-10) is obtained by subtracting the mass spectrum of the inlet from the mass spectrum of the outlet 1. A fourth difference value ‘10’ (10=20−10) is obtained by subtracting the mass spectrum of the inlet from the mass spectrum of the outlet 2. In operation S304, the system for early sensing of water leakage calculates a first identification value by summing comparison values. In this instance, the comparison values are outputted by comparing a predetermined first threshold value and each of the calculated first difference value and the calculated second difference value. That is, in operation S304, the first difference value is calculated to obtain a numerical value, that is, a summed identification value. The summed identification value may be compared to the predetermined reference value, that is, a standard for determining whether the water leaks due to the crack. Specifically, the system for early sensing of water leakage may output the comparison values, and sum the comparison values in order to obtain the first identification value. The comparison values are obtained by comparing the first threshold value with each of the first difference value and the second difference value. As an example of calculating the identification value, it is assumed that the first difference value is ‘2’, the second difference value is ‘12’, and the first threshold value is ‘5’. Here, when the first difference value or the second difference value is greater than the threshold value, the comparison values may be the first difference value or the second difference value, or a logical value ‘1’. Conversely, when the first difference value or the second difference value is less than or equal to the threshold value, the comparison value may be ‘0’ or a logical value ‘0’. Since the first difference value is ‘2’ and the threshold value is ‘5’, a first comparison value, that is, a comparison result of the first difference value and the threshold value, is ‘0’ or the logical value ‘0’. Also, since the second difference value is ‘12’ and the threshold value is ‘5’, a second comparison value, that is, a comparison result of the second difference value and the threshold value, is ‘12’ or the logical value ‘1’. Then, the system for early sensing of water leakage sums the first comparison value and the second comparison value, and thereby may calculate the first identification value, that is, ‘12’ (12=0+12) or the logical value ‘1’ (1=1+0). Also, in operation S304, a second identification value is calculated. In this instance, each of the third difference value and the fourth difference value are compared to a predetermined second threshold value, and thus comparison values are outputted. The comparison values are summed, and thus the second identification value is obtained. Since a method of calculating the second identification value is the same as the method of calculating the first identification value, a description of the method of calculating of the second identification value is omitted. In operation S305, the system for early sensing of water leakage calculates the summed identification value by summing the first identification value and the second identification value. In operation S305, the summed identification value which may be compared to the predetermined reference value, that is, the standard for determining whether the water leaks due to the crack. In operation S306, the system for early sensing of water leakage senses water leakage by comparing the calculated summed identification value and the predetermined reference value. In operation S306, the system for early sensing of water leakage senses whether the water leaks by comparing the calculated summed identification value with the predetermined reference value which is the standard for determination with respect to whether the water leaks in the steam generator or the heat exchanger. Specifically, the system for early sensing of water leakage may determine whether the water leaks by comparing the predetermined reference value and the summed identification value calculated using the measured electrical conductivity and mass spectrum. When the summed identification value is greater than the reference value, that is, ‘yes’ direction in operation S306, the system for early sensing of water leakage determines the water leaks, outputs the logical value ‘1’, and may perform a subsequent operation. Conversely, when the summed identification value is less than or equal to the reference value, that is, ‘no’ direction in operation S306, the system for early sensing of water leakage determines the water does not leak and outputs the logical value ‘0’. As an example of comparing the summed identification value and the reference value, it is assumed that the summed identification value is ‘12’ and the reference value is ‘10’. Since the summed identification value is greater than the reference value, the system for early sensing of water leakage may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the summed identification value is ‘9’ and the reference value is ‘10’, the system for early sensing of water leakage may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’, since the summed identification value is less than or equal to the reference value. As another example of comparing the summed identification value and the reference value, it is assumed that the summed identification value is the same as the logical value ‘1’ and the reference value is the same as the logical value ‘0’. Since the summed identification value is greater than the reference value, the system for early sensing of water leakage may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the summed identification value is the same as the logical value ‘0’ and the reference value is the same as the logical value ‘0’, since the summed identification value is identical to the reference value, the system for early sensing of water leakage may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’. In operation S307, when the water leakage is sensed in the steam generator or the heat exchanger, the system for early sensing of water leakage raises a leakage alarm. In operation S307, when the water leakage in the steam generator or the heat exchanger is sensed, that is, the logical value ‘1’ is outputted in operation S306, the system for early sensing of water leakage reports the leakage to a person in charge of operating the system for early sensing of water leakage. Specifically, the system for early sensing of water leakage may inform the person of the situation using light, sound, video, characters, and the like. In operation S308, the system for early sensing of water leakage outputs a first auxiliary value by comparing the first threshold value and a difference value between the electrical conductivity of the outlet 1 included in the first channel and the electrical conductivity of the inlet included in the second channel. Also, the system for early sensing of water leakage outputs a second auxiliary value by comparing the second threshold value and a difference value between the mass spectrum of the outlet 1 and the mass spectrum of the inlet. Also, the system for early sensing of water leakage outputs a third auxiliary value by comparing a third threshold value and a difference value between the electrical conductivity of the outlet 2 included in the first channel and the electrical conductivity of the inlet included in the second channel. Also, the system for early sensing of water leakage outputs a fourth auxiliary value by comparing a fourth threshold value and a difference value between the mass spectrum of the outlet 2 and the mass spectrum of the inlet. In operation S308, the first auxiliary value, the second auxiliary value, the third auxiliary value, and the fourth auxiliary value are outputted to determine whether the water leaks in a first bundle or a second bundle of the steam generator or the heat exchanger, using the measured electrical conductivity and mass spectrum. In operation S309, the system for early sensing of water leakage senses water leakage in the first bundle of the steam generator or the heat exchanger using the outputted first auxiliary value and second auxiliary value. Also, the system for early sensing of water leakage senses water leakage in the second bundle of the steam generator or the heat exchanger using the outputted third auxiliary value and fourth auxiliary value. In operation S309, the water leakage is sensed by dividing the steam generator or the heat exchanger into the first bundle and the second bundle. As an example of sensing the water leakage in the first bundle and the second bundle, when the first auxiliary value, for example, 11, is greater than the predetermined threshold value, for example, 10, or the second auxiliary value, for example, 15, is greater than another predetermined threshold value, for example, 13, the system for early sensing of water leakage may determine the water leaks in the first bundle. Also, when the third auxiliary value, for example, 11, is greater than the predetermined threshold value, for example, 10, or the fourth auxiliary value, for example, 15, is greater than the other predetermined threshold value, for example, 13, the system for early sensing of water leakage may determine the water leaks in the second bundle. Specifically, the system for early sensing of water leakage may accurately sense the water leakage occurs in the steam generator or the heat exchanger. For example, the system for early sensing of water leakage may accurately sense the water leakage occurs by dividing the steam generator or the heat exchanger into an N number of bundles. In this instance, N is a natural number. FIG. 4 is a block diagram illustrating a configuration of a system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt according to an embodiment of the present invention. A measurement unit 401 measures an electrical conductivity or a mass spectrum of a first channel and a second channel of a steam generator or a heat exchanger. The steam generator or the heat exchanger is included in the nuclear reactor system using the liquid metal and the molten salt. The measurement unit 401 may measure the electrical conductivity or the mass spectrum of the first channel including an outlet 1 and an outlet 2 of the steam generator or the heat exchanger. Also, the measurement unit 401 may measure the electrical conductivity or the mass spectrum of the second channel including an inlet of the steam generator or the heat exchanger. A correction unit 402 performs a dilution correction or a temperature compensation with respect to the measured electrical conductivity or mass spectrum. In the correction unit 402, the dilution correction or the temperature compensation with respect to the measured electrical conductivity is performed considering a fact that the measured electrical conductivity is affected by a temperature and a dilution of the sodium when measured. Specifically, the correction unit 402 may correct the measured electrical conductivity according to a standard temperature or a standard dilution. As an example of correcting the measured electrical conductivity, when measuring the electrical conductivity, the standard temperature is set to ‘15 degrees Celsius’ and the standard dilution is set to ‘4%’. It is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a temperature when measuring the electrical conductivity is different from the standard temperature by ‘±1 degree’. Also, it is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a dilution when measuring the electrical conductivity is different from the standard dilution by ‘±1%’. It is apparent that the measured mass spectrum is corrected in the same way as the measured electrical conductivity. When the temperature when measuring the electrical conductivity is ‘10 degrees Celsius’ and the dilution when measuring the electrical conductivity is ‘3%’, the correction unit 402 may consider a measurement environment to be different from the standard temperature or the standard dilution, and correct the measured electrical conductivity to be consistent with the standard temperature and the standard dilution. Specifically, when the measured electrical conductivity is ‘15S’, a corrected electrical conductivity becomes ‘9’ (9=15−5−1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. A calculation unit 403 calculates a first difference value between an electrical conductivity or a mass spectrum of the outlet 1 and an electrical conductivity or a mass spectrum of the inlet. Also, the calculation unit 403 calculates a second difference value between an electrical conductivity or a mass spectrum of the outlet 2 and the electrical conductivity or the mass spectrum of the inlet. Specifically, the calculation unit 403 may calculate a difference between the electrical conductivity or the mass spectrum of the inlet and the electrical conductivity or the mass spectrum of the outlet 1 and the outlet 2 based on a chemical reaction of sodium and water (steam). Accordingly, the calculation unit 403 may determine how significant a crack is based on the difference. Components included in the calculation unit 403 are described in detail with reference to FIG. 5. FIG. 5 is a block diagram illustrating a configuration of the calculation unit 403 of FIG. 4 in detail. As illustrated in FIG. 5, the calculation unit 403 may include a computation unit 501 and an identification value calculation unit 502. As an example of calculating of the first difference value and the second difference value, it is assumed that the electrical conductivity or the mass spectrum of the inlet is ‘10’, the electrical conductivity or the mass spectrum of the outlet 1 is ‘15’, and the electrical conductivity or the mass spectrum of the outlet 2 is ‘20’. The computation unit 501 calculates the first difference value ‘5’ (5=15−10) by subtracting the electrical conductivity or the mass spectrum of the inlet from the electrical conductivity or the mass spectrum of the outlet 1. The computation unit 501 calculates the second difference value ‘10’ (10=20−10) by subtracting the electrical conductivity or the mass spectrum of the inlet from the electrical conductivity or the mass spectrum of the outlet 2. The identification value calculation unit 502 calculates an identification value by summing comparison values. In this instance, the comparison values are outputted by comparing a predetermined threshold value and each of the calculated first difference value and the calculated second difference value. The identification value calculation unit 502 may calculate the identification value which may be compared to the predetermined reference value, that is, a standard for determining whether water leaks due to a crack. Specifically, the identification value calculation unit 502 may compare the predetermined threshold value with each of the calculated first difference value and the calculated second difference value, output the comparison values as a result of the comparing, and sum the comparison values. As an example of calculating the identification value, it is assumed that the first difference value is ‘2’, the second difference value is ‘12’, and the threshold value is ‘5’. Here, when the first difference value or the second difference value is greater than the threshold value, the comparison value may be the first difference value or the second difference value, or a logical value ‘1’. Conversely, when the first difference value or the second difference value is less than or equal to the threshold value, the comparison value may be ‘0’ or a logical value ‘0’. Since the first difference value is ‘2’ and the threshold value is ‘5’, the identification value calculation unit 502 calculates a first comparison value ‘0’ or the logical value ‘0’. The first comparison value is a comparison result of the first difference value and the threshold value. Also, since the second difference value is ‘12’ and the threshold value is ‘5’, the identification value calculation unit 502 calculates a second comparison value ‘12’, that is, the second difference value, or the logical value ‘1’. The second comparison value is a comparison result of the second difference value and the threshold value. Then, the identification value calculation unit 502 sums the first comparison value and the second comparison value, and thereby may calculate the identification value, that is, ‘12’ (12=0+12) or the logical value ‘1’ (1=1+0). The sensing unit 404 senses water leakage by comparing the calculated identification value and a predetermined reference value. The sensing unit 404 may sense whether the water leaks by comparing the calculated identification value with the predetermined reference value which is a standard for determination with respect to whether the water leaks in the steam generator or the heat exchanger. Specifically, the sensing unit 404 may determine whether the water leaks by comparing the predetermined reference value and the identification value calculated using the measured electrical conductivity or the mass spectrum. When the identification value is greater than the reference value, the sensing unit 404 determines the water leaks, outputs the logical value ‘1’, and may perform a subsequent operation. Conversely, when the identification value is less than or equal to the reference value, the sensing unit 404 determines the water does not leak and outputs the logical value ‘0’. As an example of comparing the identification value and the reference value, it is assumed that the identification value is ‘12’ and the reference value is ‘10’. Since the identification value is greater than the reference value, the sensing unit 404 may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the identification value is ‘9’ and the reference value is ‘10’, since the identification value is less than or equal to the reference value, the sensing unit 404 may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’. When sensing the water leakage in the steam generator or the heat exchanger, the sensing unit 404 raises a leakage alarm. When the water leakage in the steam generator or the heat exchanger is sensed, the sensing unit 404 reports the leakage to a person in charge of operating the system for early sensing of water leakage. Specifically, the sensing unit 404 may inform the person of the situation using light, sound, video, characters, and the like. FIG. 6 is a block diagram illustrating a configuration of a system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt according to still another embodiment of the present invention. A measurement unit 601 measures an electrical conductivity and a mass spectrum of a first channel and a second channel of a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and the molten salt. Specifically, the measurement unit 601 may measure the electrical conductivity and the mass spectrum of the first channel and the second channel of the steam generator or the heat exchanger. The first channel includes an outlet 1 and an outlet 2 of the steam generator or the heat exchanger, and the second channel includes an inlet of the steam generator or the heat exchanger. Accordingly, the system for early sensing of water leakage may measure the electrical conductivity and the mass spectrum of each of the outlet 1, the outlet 2, and the inlet of the steam generator or the heat exchanger to determine whether water leaks. A correction unit 602 performs a dilution correction or a temperature compensation with respect to the measured electrical conductivity or mass spectrum. The correction unit 602 may perform the dilution correction or the temperature compensation with respect to the measured electrical conductivity or mass spectrum considering a fact that the measured electrical conductivity or mass spectrum is affected by a temperature and a dilution of sodium when measured. Specifically, the correction unit 602 may correct the measured electrical conductivity or mass spectrum according to a standard temperature or a standard dilution. As an example of correcting the measured electrical conductivity or mass spectrum, when measuring the electrical conductivity or mass spectrum, the standard temperature is set to ‘15 degrees Celsius’ and the standard dilution is set to ‘4%’. It is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a temperature when measuring the electrical conductivity is different from the standard temperature by ‘±1 degree’. Also, it is assumed that the measured electrical conductivity is required to be corrected to be within ‘±1S’, when a dilution when measuring the electrical conductivity is different from the standard dilution by ‘±1%’. Also, it is assumed that a correction method with respect to the mass spectrum is performed in the same way as the electrical conductivity. When the temperature when measuring the electrical conductivity or mass spectrum is ‘10 degrees Celsius’ and the dilution when measuring the electrical conductivity or mass spectrum is ‘3%’, the correction unit 602 may consider a measurement environment described above to be different from the standard temperature and the standard dilution, and correct the measured electrical conductivity or mass spectrum to be consistent with the standard temperature or the standard dilution. Specifically, when the measured electrical conductivity is ‘15S’, a corrected electrical conductivity is ‘9S’ (9=15−5−1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. Also, when the measured mass spectrum is ‘14’, a corrected mass spectrum is ‘8’ (8=14−5−1) according to the standard temperature ‘15 degrees Celsius’ and the standard dilution ‘4%’. A calculation unit 603 calculates a first difference value between the electrical conductivity of the outlet 1 and the electrical conductivity of the inlet, and calculates a second difference value between the electrical conductivity of the outlet 2 and the electrical conductivity of the inlet. Also, the calculation unit 603 calculates a third difference value between the mass spectrum of the outlet 1 and the mass spectrum of the inlet, and calculates a fourth difference value between the mass spectrum of the outlet 2 and the mass spectrum of the inlet. Specifically, the calculation unit 603 may calculate the difference between the electrical conductivity and the mass spectrum of the inlet and the electrical conductivity and the mass spectrum of the outlet 1 and the outlet 2, depending on a chemical reaction of sodium and water. Accordingly, the calculation unit 603 may determine how significant a crack is based on the difference. As an example of calculating of the first difference value, the second difference value, the third difference value, and the fourth difference value, it is assumed that the electrical conductivity of the inlet is ‘10S’, the electrical conductivity of the outlet 1 is ‘15S’, and the electrical conductivity of the outlet 2 is ‘20S’. Also, it is assumed that the mass spectrum of the inlet is ‘10’, the mass spectrum of the outlet 1 is ‘15’, and the mass spectrum of the outlet 2 is ‘20’. Here, a first difference value ‘5’ (5=15−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 1. A second difference value ‘10’ (10=20−10) is obtained by subtracting the electrical conductivity of the inlet from the electrical conductivity of the outlet 2. Also, a third difference value ‘5’ (5=15−10) is obtained by subtracting the mass spectrum of the inlet from the mass spectrum of the outlet 1. A fourth difference value ‘10’ (10=20−10) is obtained by subtracting the mass spectrum of the inlet from the mass spectrum of the outlet 2. The calculation unit 603 calculates a first identification value by summing comparison values. In this instance, the comparison values are outputted by comparing a predetermined first threshold value and each of the calculated first difference value and the calculated second difference value. That is, the calculation unit 603 may calculate the first difference value to obtain a numeral value, that is, a summed identification value. The summed identification value may be compared to a predetermined reference value, that is, a standard for determining whether the water leaks due to the crack. Specifically, the calculation unit 603 may output the comparison values, and sum the comparison values in order to obtain the first identification value. The comparison values are obtained by comparing the first threshold value with each of the first difference value and the second difference value. As an example of calculating the identification value, it is assumed that the first difference value is ‘2’, the second difference value is ‘12’, and the first threshold value is ‘5’. Here, when the first difference value or the second difference value is greater than the threshold value, the comparison value may be the first difference value, the second difference value, or a logical value ‘1’. Conversely, when the first difference value or the second difference value is less than or equal to the threshold value, the comparison value may be ‘0’ or a logical value ‘0’. Since the first difference value is ‘2’ and the threshold value is ‘5’, a first comparison value, that is, a comparison result of the first difference value and the threshold value, is ‘0’ or the logical value ‘0’. Also, since the second difference value is ‘12’ and the threshold value is ‘5’, a second comparison value, that is, a comparison result of the second difference value and the threshold value, is ‘12’ or the logical value ‘1’. Then, the calculation unit 603 sums the first comparison value and the second comparison value, and thereby may calculate the first identification value, that is, ‘12’ (12=0+12) or the logical value ‘1’ (1=1+0). Also, the calculation unit 603 calculates a second identification value. In this instance, each of the third difference value and the fourth difference value are compared to a predetermined second threshold value, and thus comparison values are outputted. The comparison values are summed, and thus the second identification value is obtained. Since a method of calculating the second identification value is the same as the method of calculating the first identification value, a description of the method of calculating of the second identification value is omitted. The calculation unit 603 calculates the summed identification value by summing the first identification value and the second identification value. The calculation unit 603 may calculate the summed identification value which may be compared to the predetermined reference value, that is, the standard for determining whether the water leaks due to the crack. A sensing unit 604 senses water leakage by comparing the calculated summed identification value and the predetermined reference value. The sensing unit 604 may sense whether the water leaks by comparing the calculated summed identification value with the predetermined reference value which is a standard for determination with respect to whether the water leaks in the steam generator or the heat exchanger. Specifically, the sensing unit 604 may determine whether the water leaks by comparing the predetermined reference value and the summed identification value calculated using the measured electrical conductivity and mass spectrum. When the summed identification value is greater than the reference value, the sensing unit 604 determines the water leaks, and outputs the logical value ‘1’. Conversely, when the summed identification value is less than or equal to the reference value, the sensing unit 604 determines the water does not leak and outputs the logical value ‘0’. As an example of comparing the summed identification value and the reference value, it is assumed that the summed identification value is ‘12’ and the reference value is ‘10’. Since the summed identification value is greater than the reference value, the sensing unit 604 may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the summed identification value is ‘9’ and the reference value is ‘10’, the sensing unit 604 may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’, since the summed identification value is less than or equal to the reference value. As another example of comparing the summed identification value and the reference value, it is assumed that the summed identification value is the same as the logical value ‘1’ and the reference value is the same as the logical value ‘0’. Since the summed identification value is greater than the reference value, the sensing unit 604 may determine the water leaks in the steam generator or the heat exchanger, and output the logical value ‘1’. Conversely, when the summed identification value is the same as the logical value ‘0’ and the reference value is the same as the logical value ‘0’, since the summed identification value is identical to the reference value, the sensing unit 604 may determine the water does not leak in the steam generator or the heat exchanger, and output the logical value ‘0’. When the water leakage is sensed in the steam generator or the heat exchanger, the sensing unit 604 raises a leakage alarm. When the water leakage in the steam generator or the heat exchanger is sensed, the sensing unit 604 reports the leakage to a person in charge of managing the system for early sensing of water leakage. Specifically, the sensing unit 604 may inform the person of the situation using light, sound, video, characters, and the like. An auxiliary value outputting unit 605 outputs a first auxiliary value by comparing the first threshold value and a difference value between the electrical conductivity of the outlet 1 included in the first channel and the electrical conductivity of the inlet included in the second channel. Also, the auxiliary value outputting unit 605 outputs a second auxiliary value by comparing the second threshold value and a difference value between the mass spectrum of the outlet 1 and the mass spectrum of the inlet. Also, the auxiliary value outputting unit 605 outputs a third auxiliary value by comparing a third threshold value and a difference value between the electrical conductivity of the outlet 2 included in the first channel and the electrical conductivity of the inlet included in the second channel. Also, the auxiliary value outputting unit 605 outputs a fourth auxiliary value by comparing a fourth threshold value and a difference value between the mass spectrum of the outlet 2 and the mass spectrum of the inlet. Specifically, the auxiliary value outputting unit 605 may output the first auxiliary value, the second auxiliary value, the third auxiliary value, and the fourth auxiliary value to determine whether the water leaks in a first bundle or a second bundle of the steam generator or the heat exchanger, using the measured electrical conductivity and mass spectrum. A bundle sensing unit 606 senses the water leakage in the first bundle of the steam generator or the heat exchanger using the outputted first auxiliary value and second auxiliary value. Also, the bundle sensing unit 606 senses the water leakage in the second bundle of the steam generator or the heat exchanger using the outputted third auxiliary value and fourth auxiliary value. The bundle sensing unit 606 may sense the water leakage by dividing the steam generator or the heat exchanger into the first bundle and the second bundle. As an example of sensing the water leakage in the first bundle and the second bundle, when the first auxiliary value, for example, 11, is greater than the predetermined threshold value, for example, 10, or the second auxiliary value, for example, 15, is greater than another predetermined threshold value, for example, 13, the bundle sensing unit 606 may determine the water leaks in the first bundle. Also, when the third auxiliary value, for example, 11, is greater than the predetermined threshold value, for example, 10, or the fourth auxiliary value, for example, 15, is greater than the other predetermined threshold value, for example, 13, the bundle sensing unit 606 may determine the water leaks in the second bundle. Specifically, the bundle sensing unit 606 may accurately sense the water leakage occurs in the steam generator or the heat exchanger. FIG. 7 is a sectional view illustrating a steam generator in a nuclear reactor system using a liquid metal and molten salt according to an embodiment of the present invention. Sodium used as a coolant is injected from a sodium injection port 701 of the stream generator, and exhausted from a sodium exhaust port 702 of the stream generator. Water (steam) is injected from an inlet 703 to the stream generator, and exhausted to an outlet 1 704 and an outlet 2 705. An electrical conductivity sensor 706, installed in the inlet 703, measures an electrical conductivity at the inlet 703. Also, a sampling port 707, mounted in the inlet 703, measures a mass spectrum at the inlet 703. Also, an electrical conductivity sensor 708, mounted in the outlet 1 704, measures an electrical conductivity at the outlet 1 704. Also, a sampling port 709, mounted in the outlet 1 704, measures a mass spectrum at the outlet 1 704. Also, an electrical conductivity sensor 710, mounted in the outlet 2 705, measures an electrical conductivity at the outlet 2 705. Also, a sampling port 711, mounted in the outlet 2 705, measures a mass spectrum at the outlet 2 705. Accordingly, a system for early sensing of water leakage may sense water leakage by dividing the steam generator into a first bundle 712 and a second bundle 713. FIG. 8 is a sectional view illustrating an electrical conductivity sensor or a sampling port according to an embodiment of the present invention. The electrical conductivity sensor 801 or the sampling port 802 may be mounted in a small protuberance 803 in order not to be affected by a speed of water flow. Also, a baffle plate 804 may prevent fluid dynamic energy due to water flow from being added to an electrical conductivity sensor or a sampling port. In this instance, a temperature sensor 805 may be also mounted to correct a temperature. Further, a sight glass 806 may be mounted to check the electrical conductivity sensor 801 and the temperature sensor 805. FIG. 9 is a sectional view illustrating an apparatus where an electrical conductivity sensor or a sampling port is installed according to an embodiment of the present invention. A condensate producing reactor 901 collecting steam condensate is mounted in a water (steam) outlet pipe 902 of a steam generator. An electrical conductivity sensor 903 or a sampling port 904 measures an electrical conductivity and a mass spectrum with respect to water (steam) discharged from the condensate producing reactor 901. The above-described embodiments of the present invention may be recorded in computer-readable media including program instructions to implement various operations embodied by a computer. The media may also include, alone or in combination with the program instructions, data files, data structures, and the like. The media and program instructions may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM disks and DVD; magneto-optical media such as optical disks; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. The media may also be a transmission medium such as optical or metallic lines, wave guides, etc. including a carrier wave transmitting signals specifying the program instructions, data structures, etc. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter. The described hardware devices may be configured to act as one or more software modules in order to perform the operations of the above-described embodiments of the present invention. According to the present invention, a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt may sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may help the steam generator or the heat exchanger to control the water leakage (steam leakage). According to the present invention, a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt may sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may prevent a shutdown of nuclear reactor. According to the present invention, a method and system for early sensing of water leakage, through chemical concentration monitoring, in a nuclear reactor system using a liquid metal and molten salt may sense water leakage (steam leakage), due to a crack in a steam generator or a heat exchanger included in the nuclear reactor system using the liquid metal and molten salt, early and thereby may prevent a shutdown of the steam generator or the heat exchanger included in the nuclear reactor system using the liquid metal and molten salt. Although a few embodiments of the present invention have been shown and described, the present invention is not limited to the described embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
	description	1. Field of the Invention The present invention relates generally to melting apparatuses for melt decontamination of radioactive metal waste and, more particularly, to a melting apparatus which melt-decontaminates different kinds of metal waste generated from nuclear facilities, especially, facilities for processing or producing nuclear fuel, thus forming a decontaminated ingot from which radioactive contaminated slag is removed so that the decontaminated ingot can be recycled. 2. Description of the Related Art Industrial waste, the principal ingredients of which are ferrous metals such as stainless steel and carbon steels, is perceived as being a valuable resource, and its recycle ratio is quite high compared to other kinds of waste. Generally, the purpose of recycling waste is to cope with a dearth of natural resources and the problem of environmental pollution such as air, water or soil and other kinds of pollution. Particularly, although metal waste is a kind of waste which must be reprocessed to be recycled, given that the cost of recycling metal waste is markedly less than that of using natural resources to produce a product, it is a big loss in terms of protection of the environment or in the economic sense that metal waste is discarded rather than being recycled. Metal waste which is generated from nuclear facilities can also be reused by a recycling process in the same manner as other industrial metal waste. However, there is the possibility of such metal waste having been made radioactive by artificial neutron irradiation or been contaminated by radioactive substances used in the nuclear facilities. If such metal waste is recycled to produce products without adhering to appropriate regulations and the products are put on the market, an unspecified number of the general public may be exposed to radiation by the contaminated products. Therefore, all of the metal waste generated in radiation controlled areas in a nuclear facility is targeted for control. However, despite the case where the concentration of radio-nuclides in metal waste is infinitesimal so that it barely has any radiological effect on the public and the environment, if the same regulations are applied to the case, economic and social costs may be unnecessarily incurred. Hence, in the nuclear relevant act of South Korea, only when the concentration of radio-nuclides in metal waste is below a clearance level (a clearance limit), in other words, only when the radiological effect on the public and environment attributable to recycling of metal waste is below a disposal criterion that complies with the nuclear relevant act, is metal waste allowed to be discarded (or recycled). Furthermore, a related regulatory agency strictly requires radiation safety management and evaluation of radiological harm so that the radiological effect to the public and environment which is caused by clearance can be minimized. For example, it is expected that metal waste, such as a filter frame, a powder drum for a natural uranium, nuts, bolts and metal scraps, which were used in facilities for processing and producing nuclear fuel are contaminated with uranium compounds such as UO2, UO2F2 or U3O8. Therefore, such metal waste is regarded as radioactive waste which becomes a target of control, but if the concentration of the source of radiation pollution in the metal waste is below the clearance level, the metal waste is exempted from the regulations and is allowed to be disposed of by a recycling method or the like. If the shape of metal waste is that of a planar plate or the like which has a comparatively simple geometrical shape and a smooth surface, it can be recycled only by surface decontamination. Radioactive concentration is measured in real time during the decontamination process by a combination of a direct measurement method using a surface contamination monitor which is used in a nuclear fuel processing site and an indirect measurement method using a smear method. However, in the case of metal waste such as a nut or bolt which has a complex geometrical shape, it is impossible to directly measure its surface contamination, or it is difficult to use the smear measurement method. Therefore, such metal waste creates a lot of difficulties during decontamination or radiological monitoring processes. For the above reasons, a melt decontamination method is used. If metal waste is heated to a high temperature and melted, not only can radioactive substances in the metal be evenly distributed in a medium, but nuclear fuel material which is the source of the pollution can also be contained in slag on molten metal. The melt decontamination method uses these characteristics. If metal waste that has a complex structure which makes surface decontamination and direct radiation measurement difficult is processed by the melt decontamination method, the volume of the metal waste can be reduced, and uranium substances can be easily removed from a metal medium before the decontaminated metal waste is disposed of. Hitherto, a lot of research into a technique for melt-decontaminating metal waste that contains radioactive substances has taken place. Particularly, it has been reported that if the source of pollution is a nuclear fuel material (uranium radio-nuclide), most of the source of radiation pollution is contained in slag when melted. Although the decontamination effect is different depending on the initial conditions of contamination, the kind of melting additive and operation conditions such as the type of a melting furnace, the amount of uranium that is contained in slag when melt-decontaminating metal waste is over 1,000 times the amount of uranium that is contained in an ingot. It has been reported that as the initial degree of contamination increases, such a tendency also increases. For example, a system for melt decontamination of radioactive scrap metal was proposed in Korean Patent Registration No. 10-1016223. In this melt decontamination system, U-238, Ce-144, Cs-134, Cs-137, Sr-89, Sr-90, Ni-63, Co-58, Co-60, Cr-51, etc. are the target nuclides to be decontaminated. The system melt-decontaminates metal waste polluted by radioactivity generated in nuclear facilities, thus forming a decontaminated ingot from which slag that contains radioactivity is removed. The decontaminated ingot is recycled, and the slag that contains radioactivity is disposed of as radioactive waste. Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a melting apparatus which is a comparatively small apparatus appropriate for melt decontamination of metal waste of about 250 kg per single cycle, and which melt-decontaminates radioactive metal waste, thus forming a decontaminated ingot from which radioactive slag is removed, so that the decontaminated ingot can be recycled. In order to accomplish the above object, the present invention provides a melting apparatus for melt-decontaminating radioactive metal waste so as to allow the metal waste to be recycled, the melting apparatus including: a melting furnace comprising a crucible into which the metal waste is input, and an induction coil wound around the crucible to melt the metal waste using a current induced by electromagnetic induction, the induction coil having a hollow hole in which a cooling fluid flows; a high frequency generator applying a high-frequency current to the induction coil; a ladle supplying molten metal, from which slag has been removed in the crucible, into molds; a bogie disposed adjacent to the ladle so as to be movable in a horizontal direction, the bogie being provided with the molds, each of which forms an ingot using the molten metal supplied thereinto by the ladle; a cooling unit cooling the cooling fluid and circulating the cooling fluid along the induction coil; and a dust collector provided in the melting furnace, the dust collector filtering out dust and purifying gas generated while melting the metal waste, before discharging the gas. The bogie may be provided on a guide rail so as to be movable in the horizontal direction, the bogie being operated by a motor. The molds may be provided on the bogie such that each of the molds is able to be turned upside down. The melting furnace may include: a first support member rotatably supporting a first rotational shaft provided on the melting furnace; and a rotation drive unit rotating the melting furnace around the first rotational shaft. The ladle may include: a second support member rotatably supporting a second rotational shaft provided on the ladle; and a second rotation drive unit rotating the ladle around the second rotational shaft. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Referring to FIG. 1, a melting apparatus for melt decontamination of radioactive metal waste according to the present invention includes a melting furnace 110, a high frequency generator 120, a ladle 130, a bogie 140, a cooling unit 150 and a dust collector 160. The melting furnace 110 melts metal waste using current induced by electromagnetic induction. The high frequency generator 120 applies high-frequency current to the melting furnace 110. The ladle 130 pours molten metal, from which slag has been removed in the melting furnace 110, into a mold 141. The bogie 140 has a plurality of molds 141 into which molten metal is injected from the ladle 130 to form ingots. The cooling unit 150 cools cooling fluid that circulates along an induction coil provided on the melting furnace 110. The dust collector 160 removes dust and purifies gas generated in the melting furnace 110. The melting furnace 110 uses a high-frequency induction heating method. When AC high-frequency current is applied to a coil, alternate magnetic flux is generated around the coil, so that induced current is generated in a conductor disposed in this magnetic field. This current is called eddy current. The inductive heating melting furnace becomes a heat generating source wherein heat is generated by eddy current and specific resistance of metal that is a target to be heated. The inductive heating melting furnace is advantageous in that the homogeneity of an ingot is ensured because molten metal is agitated in the melting furnace. This makes it easy to measure the level of radiation of an ingot that has been formed after a melt decontamination process has been conducted. Further, compared to other melting furnaces, there are advantages of easy melting operation and reduced metal loss. Referring to FIG. 2, the melting furnace 110 of the present invention includes a crucible 111 into which metal waste is charged, an induction coil 112 which is wound around the crucible 111, and a structure which encloses the induction coil 112 and supports the crucible 111 and the induction coil 112. In other words, the melting furnace 110 includes the crucible 111 which is open on an upper end thereof so that metal waste and an impurity remover are supplied into the crucible 111 through the open upper end thereof, the induction coil 112 which is wound around the crucible 111 in a spiral shape, and a housing 113 which encloses the crucible 111 and the induction coil 112. The induction coil 112 has a hollow space 112a through which cooling fluid flows. The cooling fluid circulates along the hollow space 112a, thus reducing heat generated in the induction coil 112 itself. The cooling fluid that circulates through the induction coil 112 may be water (distilled water) or gas. The crucible 111 provided with the induction coil 112 is received and supported in the housing 113. In the present invention, the melting furnace 110 is supported by two support members which are firmly fixed to the support surface and are symmetrical with each other. Particularly, the melting furnace 110 is rotatably supported on upper ends of the support members so that after decontamination has finished, the melting furnace 110 can be tilted to pour molten metal out of it. This structure will be explained in more detail later herein with reference to FIG. 5. The high frequency generator 120 is electrically connected to the induction coil 112 of the melting furnace 110. High-frequency current generated from the high frequency generator 120 is applied to the induction coil 112 of the melting furnace 110. Thereby, metal waste that has been supplied into the crucible 111 is melted by eddy current induced by electromagnetic induction. The ladle 130 is disposed adjacent to the melting furnace 110 and functions to pour molten metal into a mold 141 after the melt decontamination in which slag is removed from the molten metal in the crucible 111 has been completed. In the same manner as the melting furnace 110, the ladle 130 is supported by two second support members which are firmly fixed to the support surface and are symmetrical with each other. Preferably, the ladle 130 is rotatably supported on upper ends of the second support members so that the ladle 130 can be tilted to pour molten metal into the mold 141. This structure will be explained in detail later herein with reference to FIG. 5. The bogie 140 is disposed adjacent to the ladle 130 and provided so as to movable in the horizontal direction. The bogie 140 is provided with the molds 141. Molten metal that is injected into each mold 141 is cooled, thus forming an ingot. Preferably, a guide rail 145 is installed on the support surface to guide the direction in which the bogie 140 moves. The bogie 140 includes a rectangular frame 142 which supports structures thereon, a plurality of wheels 143 which are rotatably provided under the frame 142, and the molds 141 which are provided on the frame 142. The wheels 143 that are provided under the frame 142 are connected to an electric motor 144 by a power transmission member, such as a chain or a belt. Thereby, the wheels 143 can be electrically operated. Each of the molds 141 that are provided on the frame 142 is configured such that it can be turned upside down to facilitate removal of an ingot produced using the mold 141. Preferably, a pair of support brackets 142a is provided on the frame 142 at a position corresponding to each mold 141. A rotational shaft 141a of each mold 141 is supported by the corresponding support brackets 142a. A lever 141b protrudes sideways from a side surface of each mold 141 to allow a worker to grasp the lever 141b and turn the mold 141 so that an ingot can be easily removed from the mold 141. A fixing bracket 141c is coupled to two adjacent molds 141 by bolts or the like so that the two adjacent molds 141 are fixed to each other, thus preventing the molds 141 from undesirably turning when molten metal is being poured into the molds 141. Referring to FIG. 1, the cooling unit 150 functions to cool and circulate the cooling fluid along the induction coil of the melting furnace 110. The cooling unit 150 includes a cooling pump 151 and a cooling fan 152. The cooling pump 151 is connected to the induction coil 112 of the melting furnace 110 to circulate the cooling fluid along the induction coil 112. The cooling fan 152 functions to cool the cooling fluid that is circulated by the cooling pump 151. The cooling unit 150 may be configured such that the cooling fluid is able to continuously circulate when the melting furnace 110 is being operated. Alternatively, a separate control unit may be provided along with a sensor which is provided on the induction coil 112 of the melting furnace 110 or a circulation pipe so as to sense the temperature of the cooling fluid, wherein the control unit controls the circulation of the cooling fluid depending on its temperature. The dust collector 160 is provided on the melting furnace 110. The dust collector 160 filters out dust or purifies gas generated during the operation of the melting furnace 110 and then exhausts it. As a detailed example, referring to FIG. 4, the dust collector 160 includes a filter body 162 which has a container-shape and includes an inlet port 161 that is connected, by a duct, to a hood (not shown) disposed above the melting furnace. A filter cartridge is provided in the filter body 162 to remove dust or the like from air that is drawn into the filter body 162. A dust collection unit 163 is provided under a lower end of the filter body 162 to collect the dust removed from air. To prevent accumulated dust from clogging the filter cartridge that is provided in the filter body 162 and filters out dust, an air pulse method in which a blow pipe periodically supplies compressed air to the filter cartridge to remove dust from the filter cartridge is used. A discharge port 164 is provided on the lower end of the filter body 162 so that filtered gas is discharged out of the filter body 162 by the discharge port 164. The discharge port 164 is connected to a duct so that filtered gas can be exhausted to the outside via an exhaust duct 166 by suction pressure generated by a blower 165. FIG. 5 is side view illustrating the operation of critical parts of the melting apparatus according to the present invention. The melting furnace 110 includes the first support members 171 which rotatably support a first rotational shaft 171a of the melting furnace 110, and a rotation drive unit which rotates the melting furnace around the first rotational shaft 171a. Lower ends of the first support members 171 are firmly fixed on the support surface, and the first rotational shaft 171a of the melting furnace 110 is rotatably coupled to the upper ends of the first support members 171. A first cylinder 172 which functions as a first rotation drive unit is provided to rotate the melting furnace 110 around the first rotational shaft 171a. A lower end of the first cylinder 172 is provided on the support surface so as to be rotatable by a first rotary shaft 172a. An upper end of the first cylinder 172 is rotatably coupled to the melting furnace 110 by a second rotary shaft 172b. The first cylinder 172 is extended or contracted in the longitudinal direction by hydraulic or pneumatic pressure. Depending on the degree of extension or contraction of the first cylinder 172, the melting furnace 110 can rotate around the first rotational shaft 171a, thus pouring molten metal into the ladle 130. In the same manner, the ladle 130 includes the second support members 181 which rotatably support a second rotational shaft 181a of the ladle 130, and a second rotation drive unit which rotates the ladle 130 around the second rotational shaft 181a. Lower ends of the second support members 181 are firmly fixed on the support surface, and the second rotational shaft 181a of the ladle 130 is rotatably coupled to the upper ends of the second support members 181. A second cylinder 182 which functions as a second rotation drive unit is provided to generate drive force by which the ladle 130 can be rotated around the second rotational shaft 181a. A lower end and an upper end of the second cylinder 182 are respectively rotatably coupled to the support surface and the ladle 130. The second cylinder 182 is extended or contracted by hydraulic or pneumatic pressure in the longitudinal direction. Depending on the degree of extension or contraction of the second cylinder 182, the ladle 130 can rotate around the second rotational shaft 181a, thus pouring molten metal into the corresponding mold 141 that is disposed adjacent to the ladle 130. A hydraulic unit 190 of FIG. 1 is a hydraulic pressure control device which controls a hydraulic signal that is applied to the first cylinder that drives the melting furnace 110 or to the second cylinder that drives the ladle 130. The melting apparatus according to the present invention having the above-mentioned construction conducts a melt decontamination process in which metal waste is input into the melting furnace 110, and a single additive or more are added to molten metal depending on characteristics of metals to be melted and a content of impurities. In detail, melting metal waste includes applying high-frequency current generated from the high frequency generator 120 to the induction coil 112 of the melting furnace 110 so that current induced by electromagnetic induction is generated in the metal waste in the crucible 111 disposed inside the induction coil 112, thus melting the metal waste. During the melting process, the cooling unit 150 connected to the induction coil 112 circulates the cooling fluid along the induction coil 112, preventing the induction coil 112 from overheating. Meanwhile, the dust collector 160 connected to the melting furnace 110 removes dust and purifies gas generated during the melting process before discharging the gas to the outside. An impurity remover (SiO2) which removes impurities from the molten metal is input into the melting furnace 110 as the melting additive. The impurity remover causes impurities including radio-nuclides to form slag on the surface of the molten metal. Furthermore, recarburizer and ferrosilicon may be input as other melting additives along with metal waste at the initial stage of the melting process so as to adjust the carbon content of the molten metal and increase fluidity of the molten metal. Because the density of slag created in the molten metal is lower than that of melting metals, the slag floats on the surface of the molten metal. Radio-nuclides that have been in the melting metal moves from metals to the slag, thus forming a more stable oxide in the slag. After slag created in the molten metal has been removed, the decontaminated molten metal is poured into the ladle 130. Molten metal that has been poured in the ladle 130 is supplied into the molds 141 and then cooled in the molds 141 for a predetermined period of time, thus producing ingots. It is preferable for a small amount of deoxidizer (Al2O3) to be input into the molten metal to prevent bubbles from being created because of oxidation while forming ingots. Referring to FIG. 4, after the melt decontamination process has been completed, the first cylinder 172 is extended so that the melting furnace 110 is tilted around the first rotational shaft 171a, thus pouring molten metal from the melting furnace 110 into the ladle 130. After a predetermined amount of molten metal has been supplied into the ladle 130, the bogie 140 is disposed adjacent to the ladle 130 and then the second cylinder 182 is extended so that the ladle 130 is tilted around the second rotational shaft 181a, thus pouring molten metal from the ladle 130 into the molds 141. After a predetermined amount of molten metal has been supplied into each of the molds 141 of the bogie 140, it is cooled for a predetermined period of time, thus producing a decontaminated ingot. The decontaminated ingots are thereafter removed from the molds 141. Subsequently, the ingots take part in a radioactivity investigation. If the amount of detected radioactivity of each ingot is below a disposal limit, the ingot is recycled. If it is beyond the disposal limit, the ingot is processed again by melt decontamination. As described above, a melting apparatus for melt decontamination of radioactive metal waste according to the present invention includes a melting furnace which uses a high-frequency induction heating method, a cooling unit and a dust collector which are provided to reliably and efficiently operate the melting furnace, a ladle which is used to supply molten metal into molds that form ingots, and a bogie which is provided with the molds. It was confirmed in a process of decontaminating metal waste of about 250 kg per a cycle that the melting apparatus of the present invention can efficiently and effectively decontaminate metal waste. Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
	abstract	A concrete cask enabling suppression of occurrence of stress corrosion cracking (SCC) in a lid welded part of a canister. The concrete cask includes: a metal canister accommodating spent fuel; a concrete container body for accommodating the canister inside the container body; a cooling passage provided between the external peripheral surface of the canister and the internal peripheral surface of the container body, and allowing air for cooling the external peripheral surface of the canister to pass; and a top space provided between the top surface part of the canister, and the inside of a lid of the container body. A baffle plate for suppressing introduction of air rising through the cooling passage to the top space is provided.
	summary
	abstract	A collimator for a radiotherapy apparatus comprising a block of radiation-attenuating material having a front face forming the leading edge of the block and at least one main rear face defining the trailing edge of the block, in which the least one main rear face has a material disposed thereon and is non-parallel to the front face. The collimator may form part of a radiotherapy apparatus, and methods of operation of such apparatus are described.
	abstract	The present invention relates to a kit for radiolabelling a targeting agent with gallium-68. The present invention also relates to the use of the kit for radiolabelling a targeting agent, and a method for radiolabelling a targeting agent with gallium-68 using the kit.
	abstract	The present invention provides a charged particle beam energy width reduction system. The system comprises a first element acting in a focusing and dispersive manner in an x-z-plane; a second element acting in a focusing and dispersive manner in the x-z-plane; a charged particle selection element positioned between the first and the second element acting in a focusing and dispersive manner; and a focusing element positioned between the first and the second element acting in a focusing and dispersive manner.
039403106	claims	1. A pressurized-water reactor comprising a reactor pressure vessel having an inside with an upper portion and a lower portion, said portions containing pressurized-water core coolant, a nuclear core in said lower portion, said core comprising fuel element and at least three substantially vertical control rod guide tubes therein, said guide tubes having top and bottom ends, a duct interconnecting said bottom ends, a guide tube adaptor positioned in said upper portion of said vessel and above said core, said adaptor comprising a substantially vertically high-pressure feed line tube having a bottom end releasably connecting with said top end of a first one of said guide tubes, said adapter also including a substantially vertical guide tube extension for each of said other guide tubes, each said guide tube extension having a bottom end registered with a top end of a respective one of said other guide tubes, said extensions each having a top end having a passage for said coolant, and which is open to said vessel's said upper portion, a control rod reciprocative in each of said other guide tubes and their respective guide tube extensions, said first one of said guide tubes being void of any control rod said feed line tube having a top end, and means for controllably removing a portion of said coolant from said vessel and increasing the removed coolant's pressure and returning the coolant to said top end of said high-pressure feed line. 2. The reactor of claim 1 in which said duct interconnecting said bottom ends of said guide tubes, is formed in a base plate to which the just-named bottom ends are connected. 3. The reactor of claim 1 in which said guide tube forms a space around said control rod and at least a portion of said high-pressure feed line tube has a cross sectional area less than the cross sectional area of said space. 4. The reactor of claim 1 in which said means comprises a pump, a suction line connecting said pump with said vessel, and a high pressure line having a pressure-responsive valve means and connecting said pump through conduit means with said top end of said adaptor's said high pressure feed line, said valve means closing in response to a pressure increase. 5. The reactor of claim 1 having a flexible coupling connecting said bottom end of each of said guide tube extensions with a respective top end of other second one of said guide tubes. 6. The reactor of claim 1 in which said guide tube extensions and their respective guide tubes have their respective registered said bottom and said top ends, separated by a space providing tolerance for thermal movements of said guide tube extension and said guide tube.
050900447	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an X-ray examination apparatus and more particularly, to an X-ray examination apparatus for examining the circulatory system, such as, the blood vessels and the heart. 2. Description of the Related Art X-ray examination of the circulatory system is broadly classified into two methods. One method is angiocardiography in which blood flow, the running and form of the blood vessels, the movement of the heart, etc. is X-rayed by injecting a contrast medium of a high X-ray absorption property into the heart or blood vessel. The other one is cardio catheterization in which the circulation of blood or the cardic function is examined by inserting a catheter into the heart or blood vessel and blood pressure or the rate of blood flow is quantitatively measured. In both of these examination methods, a catheter is inserted into a blood vessel from the brachial or femoral region of a subject to be examined. The method of inserting a catheter from the brachial region is called the Sones method and the method of insertion from the femoral region is called the Judkins method. In performing an X-ray examination by inserting a catheter into the brachium of the subject, an arm is placed on an arm rest and insertion of the catheter takes place under X-ray fluoroscopy. Therefore, it is necessary to protect the operator handling the catheter against scattered X-rays. X-ray protection gloves and protection aprons, for example, are available as means for protecting the catheter-handling operator against scattered X-rays. There exist difficulties, however, with the protecting gloves in that a fine touch in operating the catheter is not fully conveyed to the operator. SUMMARY OF THE INVENTION An object of this invention is to provide an X-ray examination apparatus capable of protecting the operator's arms/hands against scattered X-rays during catheterization by inserting a catheter into a blood vessel of the subject from the brachial region. To accomplish the above object, the invention provides an X-ray examination apparatus which comprises a bed having arm rest means for supporting a brachial region of a subject when an operator inserts a catheter into a blood vessel of the subject from the brachial region; means for radiating X-rays to the subject lying on the bed; means for converting X-rays passing through the subject into an X-ray image; X-ray shield means, mounted on the arm rest means, for protecting arms/hands of the operator against scattered X-rays.
	abstract	A system for storing nuclear fuel, the system including a storage rack and a bearing pad. The storage rack includes an array of cells, each cell configured to receive and store nuclear fuel rods, a base plate configured to support the array of cells, and a support structure configured to support the base plate and to allow cooling fluid to circulate under and up through apertures in the base plate. The bearing pad is coupled to the support structure and is configured to limit lateral movement of the storage rack independent from lateral movement of the bearing pad. The base plate defines a base plate profile in a horizontal plane of the base plate, and the bearing pad defines a bearing pad profile in the horizontal plane of the base plate, wherein the bearing pad profile extends outside of the base plate profile.
	abstract	Slip joint clamps seat on a diffuser end via external features of the diffuser, like guide ears, regardless of slip joint wear or damage. The clamps can be opened and closed to surround an inlet mixer forming a slip joint with the diffuser without disassembly. Slip joint clamps drive or bias the inlet mixer in a lateral direction largely perpendicular to the axial orientation and end of the diffuser to achieve a desired preload force in the inlet mixer and clamp connection. Clamp arms include rotatable halves that, when joined, form a complete fill between an inner surface of the diffuser and outer surface of the inlet mixer. A lateral drive pushes the inlet mixer against the clamp and may include a resistive element. An accessible set of guide ear bolts and lateral driving bolts permit exterior manipulation to axially mount or laterally bias the clamp in the slip joint.
	abstract	The present invention relates to an alternate feedwater injection system to at least partially mitigate the effects of an aircraft impact on a light water nuclear reactor positioned in a reactor building. The light water nuclear reactor has a primary system and a reactor core. The alternate feedwater injection system includes a water storage tank, an injection point into the primary system, a pump capable to transfer water from the water storage tank to the injection point and ultimately to the reactor core. The water storage tank and pump are located external to a reactor building and outside of an identified aircraft impact area or inside the identified aircraft impact area and provided with a means of protection from the aircraft impact.
047553529	claims	1. In a swimming pool type nuclear reactor, a thermodynamic system for converting heat produced by the reactor to a more useful form of energy, comprising: a pool containing light water functioning as a moderator-coolant-shielding for the reactor and being open to atmospheric pressure; moderator-coolant passage means having an intake end and a discharge end and defining a flow of the moderator-coolant between the ends, the both ends and a substantial part of the passage means being positioned in the pool; the said discharge end having pressure restriction means; a nuclear reactor core containing a fissionable material, the said reactor core being positioned inside the pool and located in the moderator-coolant passage means; pump means provided in the passage means near the said intake end, the said pump means, in cooperation with the said pressure restriction means to circulate the light water contained in the pool through the passage means under an appropriately sufficient pressure so that the light water is heated above 100.degree. C. but the surface subcooled nucleate boiling is still maintained in the reactor core; primary heat exchanger means in the moderator-coolant passage means between the reactor core and the discharge end to transfer heat energy of the light water to a heat exchanger fluid contained in a secondary circuit, the said primary heat exchanger means being located in the pool; boiler means provided in the secondary circuit to heat an organic fluid contained in a turbine circuit; turbine means being provided in the turbine circuit so that the heated organic fluid drives the turbine means; condenser means in the turbine circuit to condense the heated organic fluid; and an electric generator connected to the turbine means to be driven thereby to generate electricity. poison solution tank means containing a poison solution under pressure higher than atmospheric pressure, and injection means provided on the passage means to inject the poison solution thereinto. the heat exchanger fluid is light water and the organic fluid is Freon [Trade Mark]. 2. The thermodynamic system according to claim 1 wherein: the pump means is provided in a part of the passage means located outside the pool near the intake end to draw the light water from the pool and circulate it under pressure through the passage means and back to the pool by the discharge end. 3. The thermodynamic system according to claim 2 wherein: the said primary heat exchanger means is located below the reactor core. 4. The thermodynamic system according to claim 3 further comprising: 5. The thermodynamic system according to claim 4, wherein:
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	summary
047568526	description	DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the passive vent employed in a nuclear waste storage container 10. The nuclear waste storage container 10 consists of a cask 12 open on one end. A cover 16 is secured and sealed to the open end of cask 12 so that the cask 12 and cover 16 define a nuclear waste storage chamber 14. In FIG. 1, a port 18 is shown located in the cover 16, defining a passageway between the chamber 14 and the environment 20 that surrounds the nuclear waste storage container 10. A vent plug 22, described in greater detail below, is inserted in port 18, passively venting nuclear waste storage container 10. The nuclear waste 24, however, is effectively confined within chamber 14, protecting the environment 20 from the effects of the nuclear waste 24. Pressure differences between the environment 20 and chamber 14, created by temperature changes or gas generation within the chamber 14, are relieved by vent plug 22, preventing an overpressurization of the nuclear waste storage container 10. While FIG. 1 shows vent plug 22 located in the cover 16, a passive vent may be formed by placing vent plug 22 in a port 18 provided in any of the walls of container 10. It should be noted, however, that maximum air diffusion through vent plug 22 occurs when port 18 is located above the level of nuclear waste 24 in the chamber 14. For that reason, the location of port 18 in the cover 16, as shown in FIG. 1, is often preferred as a convenient arrangement for ensuring maximum air diffusion. The passive vent system illustrated in FIG. 1 additionally shows vent plug 22 recessed in port 18. In this manner, the vent plug 22 is protected from physical damage should the nuclear waste storage container 10 be dropped or struck by an object during shipping or handling. FIG. 2 is a pictorial view illustrating the vent plug 22 of FIG. 1 in greater detail. The body of vent plug 22 is substantially cylindrical and has an external face 26 that is exposed to the environment 20 when vent plug 22 is installed in port 18. Similarly, vent plug 22 has an internal face 28 that is exposed to the chamber 14 upon insertion of vent plug 22 in the port 18. A substantially cylindrical contact face 30 completes vent plug 22, connecting external face 26 to internal face 28 and difining a surface that contacts the wall of port 18 when plug 22 is installed in port 18. The vent plug 22 is formed from a reversibly porous, air-diffusible, water-restrictive polymer capable of properly venting the chamber 14 and enduring the rigors imparted by the environment 20 of the container 10 and the waste 24 stored therein. Low-density, linear porous polyethylene has been found acceptable for this purpose and the currently preferred material for vent plug 22 is available from General Polymeric Co., 621 Franklin Street, West Reading, Pa. 19611, under the trademark QUICKUP, part number 200-12A. Selection of porous polyethylene as the plug material provides a number of advantages. First, polyethylene is relatively resistant to the effects of nuclear radiation. For example, polyethylene is reported to maintain 80 percent of its strength when subject to a radiation level of 10.sup.9 rads. Even when the strength of the polyethylene is impaired, the most significant effect is on the material's ability to tolerate deformation. Because the vent plug 22 is subject to litte or no deformation, and because the radiation in a typical storage system is on the order of 10.sup.8 rads, or less, polyethylene can endure the effects of the radiation emitted by the nuclear waste 24 stored within chamber 14. Polyethylene also has the chemical resistance required of a vent plug 22. Polyethylene is highly resistant to deterioration from inorganic materials. While it is less resistant to the influence of organic materials, these materials are unlikely to occur in concentrations sufficient to cause deterioration of the vent. In addition, deterioration occurring as a result of the absorportion of organic material into the polyethylene simply softens or weakens the material. Thus, even if some deterioration occurred, the resultant decrease in vent strength would not be critical because vent plug 22 is not subject to significant loading. The use of polyethylene also satisfies various other environmental criteria imposed on passive vents for use with nuclear waste storage containers 10. Galvanic coupling with the wall of nuclear waste storage container 10, as well as corrosion, is eliminated. The vent plug 22, so comprised, has also proved satisfactory in withstanding the loading effects of the pressure developed within chamber 14 and the burial and compressive loads imposed by the environment 20. Finally, the plug 22 remains securely in place when the waste storage container 10 is exposed to vibration and when container 10 is dropped from heights simulating potential impacts that might be experienced during shipping and handling. The requirement that the vent allow air to flow through plug 22, while simultaneously restricting the flow of liquids, is satisfied by the reversibly porous, air-diffusible, water-restrictive nature or the material. The vent, constructed from such material, allows gases generated within chamber 14 to escape to the environment 20, preventing overpressurization of container 10. These gases include hydrogen, oxygen, carbon dioxide, carbon monoxide, nitrogen, and methane, generated by the polyethylene material, ion-exchange resins, and wastes stored in the container. If the environment 20 is at a higher pressure than chamber 14, air may also diffuse into chamber 14 through vent plug 22. The pressure of environment 20 and chamber 14 are, thus, equalized, relieving any stress placed on the walls of nuclear waste storage container 10. As noted, such a vent plug 22 also restricts the flow of liquids. The magnitude of the restrictive effect is proportional to the amount of liquid present in the plug 22. The liquid causes the material to swell and, because the cross-sectional area of plug 22 is constrained by port 18, the effective porosity of the material decreases. Thus, while some flow of liquids through vent plug 22 is possible, it becomes severely restricted when the entire plug 22 is saturated. In this condition, the diffusibility of the material to air is also reduced. The resultant airflow, however, is sufficient for the vent to remain operative. An added benefit is provided by the reversibly porous nature of the material, which allows a vent, once saturated, to regain its orginally high air-diffusibility when dried. The water-restrictive nature of plug 22 restricts the escape of nuclear waste 24 in liquid form through the passive vent. Thus, although the nuclear waste storage container 10 is generally intended for storage at dry locations, groundwater present around the container is protected from contamination by the waste stored in container 10. This is true even though a continuous communication between chamber 14 and external environment 20 is provided to relieve pressure variations between the two. The average porosity of the material utilized in plug 22 is selected in view of several factors. The pore size of the material is generally inversely proportional to the cross-sectional area of the vent plug 22 required to obtain a given amount of venting. Thus, relatively small pores may require use of a correspondingly large vent plug 22. While larger pores enhance the venting of container 10, the ability of vent plug 22 to restrict the flow of liquids is impaired. In the preferred embodiment, an average pore diameter of one micron, employed in a vent plug having a cross-sectional area of less than 0.5 square inch (approximately 3.2 square centimeters), has been found suitable. A cross-sectional area of less than 0.5 square inch is desirable for vent plug 22 because, in the unlikely event vent plug 22 is displaced from port 18, the resultant opening formed by port 18 in the container wall will be relatively small. While liquids would be free to transfer between the environment 20 and chamber 14 of nuclear waste storage container 10 in this condition, the restrictive effect of the reduced opening would keep such transfer at a minimum. FIG. 2 also indicates the manner in which the currently preferred embodiments of vent plug 22 are secured to the wall of port 18. In FIG. 2, the contact face 30 of vent plug 22 is provided with threads 32 that engage with mating threads provided in the wall of port 18. A means 34 for receiving a tool for driving vent plug 22 into port 18 is provided on the external face 26 of vent plug 22. As illustrated in FIG. 2, one suitable means 34 is a slot for a screwdriver bit. Other means of receiving an insertion tool capable of inducing rotation of vent plug 22 include, for example, a female depression for use with an allen wrench or Phillips head screwdriver. FIG. 3 illustrates one embodiment of vent plug 22 prior to insertion in a wall 36 of nuclear waste storage container 10. Vent plug 22 has a cylindrical height or thickness that is greater than the thickness of wall 36. The excess thickness roughly defines an excess region 38 of vent plug 22 that extends beyond the external surface 40 of wall 36 when vent plug 22 is properly seated in wall 36 (FIG. 4). From FIG. 4, it is clear that the means 34 for receiving an insertion tool lies within this excess region 38. Excess region 38 can be removed from vent plug 22 in a manner leaving an exposed surface of vent plug 22 that is substantially flush with (or protrudes slightly from) the external surface 40 of wall 36 (FIG. 5). In this manner, a vent installed in a nuclear waste storage container 10 having a relatively thin wall 36 may be protected both from tampering and from environmental forces incurred by the container wall 36. With the means 34 for receiving the insertion tool removed, vent plug 22 cannot be easily removed by unauthorized personnel. Thus, tampering with the passive vent is reduced. Additionally, groundwater cannot collect in the means 34. Because the exterior of the passive vent lies substantially flush with the external surface 40 of wall 36, any impact or other force on wall 36 is distributed to the wall 36 rather than directly to vent plug 22, protecting the plug. Preferably, vent plug 22 is sealed within port 18 to ensure that neither liquid nor gas passes between contact face 30 of plug 22 and the walls of port 18. As indicated in FIG. 3, a thread sealant 44 that is impervious to gas and liquid can be applied to contact surface 30 for compression between the contact surface and port 18 when vent plug 22 is installed. One such sealant tape is formed of a fluorocarbon resin that is commonly known as "Teflon" (a trademark of E.I. duPont de Nemours & Company). From the preceding discussion, it can be recognized that the invention provides a method of forming a passive vent in a nuclear waste storage container. Pursuant to this method, a vent plug is formed in the manner, and of the material, described herein. If necessary, a sealant is applied to the vent plug 22 prior to installation in port 18 to prevent gas or liquid from passing around the vent plug. Next, vent plug 22 is inserted in port 18 of wall 36 by applying an insertion tool to the receiving means 34 of vent plug excess region 38. Vent plug 22 is then inserted a predetermined distance, for example, until the interal face 28 of vent plug 22 extends slightly beyond the internal surface 42 of wall 36 as shown in FIG. 4 or until vent plug 22 is properly seated. At this point, the excess region 38 of vent plug 22 is removed, leaving a passive vent as shown in FIG. 5. As noted previously, the resulting vent is subject to a reduced likelihood of collecting water, being tampered with by unauthorized personnel, or damaged from forces exerted upon the external surface 40 of wall 36 by foreign objects. Vent plug 22, after this step, may optionally protrude slightly from the external surface 40 of wall 36 to prevent water from accumulating at port 18. It is to be understood that the invention may be practiced with other specific forms of apparatus without departing from the spirit or basic characteristics of the invention. For example, the body of the vent plug may be shaped like a cylinder, polyhedron or frustum of a cone. Similarly, the location of the plug in the wall of the housing, while providing optimal venting when above the waste level in the container, can be anywhere. Alternative means of securing the vent plug in the container wall may be employed. The scope of the invention is, therefore, to be determined by the appended claim rather than by the drawings and foregoing description.
	abstract	Disclosed is an X-ray imaging system that comprises a high ratio, high primary transmission anti-scatter grid in combination with a dynamic X-ray tube output function to eliminate or reduce gridline artifacts. Conventional X-ray imaging systems utilizing conventional anti-scatter grids generally require that the grid be moved a distance of at least 20 grid pitches to eliminate gridline artifacts. Through the use of the anti-scatter grid and dynamic output function described, such artifacts are eliminated or substantially reduced when the grid travels a short distance. Any function that has zero frequency components at positive integer multiples of the reciprocal of the grid repeat time will completely suppress gridline artifacts. Any function that is equal to the convolution of an arbitrary function with a rect function whose width is a positive multiple of the grid repeat time will fit this criterion, and its use will completely suppress gridline artifacts.
	description	In accordance with preferred embodiments of the present invention, electromagnetic fields may be used to raster scan the focal spot of an x-ray tube across the x-ray tube target, thereby advantageously allowing a smaller focal spot to be obtained without requiring additional power dissipation capacity. Fundamental components of a typical x-ray generator 10 are described with reference to FIG. 2. A beam 12 of charged particles is emitted by a particle source 14 which, in the case of electrons, is typically a cathode. Beam 12 of charged particles may be referred to herein, without limitation, as an electron beam, though reversal of electrical polarities, in the case of a beam of positive ions, is known to persons skilled in the art and is within the scope of the present invention. Electron beam 12 is accelerated toward target 16 either by virtue of a positive electrical potential applied to target 16 with respect to cathode 14 or by means of one or more accelerating grids intervening between cathode 14 and target 16 as known to persons skilled in the electronic arts. The size of focal spot 18, where electron beam 12 impinges upon target 16, defines the region of target 16 that emits x-ray emission 20, and may thus be a limiting factor in the resolution of any image obtained using x-ray emission 20. As discussed in the background section above, the size of focal spot 18 also determines the electron energy density that must be dissipated by target 16. If focal spot 18 is scanned across target 16, such as along the two-dimensional pattern designated generally by the dotted line denoted 22, the electron energy may be dissipated over a larger area of target 16 than if the focal spot remains stationary. Steering of beam 12 may be provided by any of a variety of electromagnetic steering arrangements such as, by way of example, magnetic coils 24 placed around the trajectory of beam 12 or by means of an electrostatic lens. Additionally, as known to persons skilled in the art of x-ray tubes, the size and shape of beam 12 as it impinges upon target 16 may also be adjusted by operation of steering arrangement 24. The focal spot can be raster-scanned across target 16 in two dimensions much like the electron beam in a television cathode ray tube, or it can be raster-scanned in only one dimension. Clearly, the size of the focal spot can be made smaller with a two dimensional scan because the electron beam energy is dissipated over a larger area of the target. The raster scanning can be achieved, for example, by applying a sinusoidal waveform to coils 24. Other waveforms can be used depending on the scanning pattern that is advantageous in a particular application. Referring now to FIG. 3, application of the scanning of the focal spot 18 of electron beam 12 across the face of target 16 is now discussed in the context of a system in which the direction of x-ray beam 64 is varied for purposes of imaging in accordance with preferred embodiments of the invention. In the embodiment depicted in FIG. 3, x-ray beam 64 has a substantially circular cross section and is a xe2x80x9cpencilxe2x80x9d beam. Direction 64 (also representing the x-ray beam) is an instantaneous direction of propagation, as defined by collimator jaw 30. The position of collimator jaw 30 relative to the source of x-ray beam 20 is typically varied as a function of time by a beam director which may be a mechanical chopper wheel 61 or, alternatively, may be an oscillating slot mechanism or other beam direction arrangement, some of which mechanisms are discussed below in the context of alternate embodiments of the invention. X-rays 20 are blocked from propagating along any direction other than through collimator jaw 30 by virtue of the x-ray opacity of the beam director 61, shown here as a rotating chopper wheel. As chopper wheel 61 rotates in a counterclockwise direction, x-ray beam 64 is sweep in the direction designated by arrow 32. The center of rotation of chopper wheel 61 defines an effective center 36 on the surface of target 16. In accordance with preferred embodiments of the invention, focal spot 18 is scanned along a scan path 34 such that the centroid of focal spot 18 always lies instantaneously on line 64 along which x-rays are emitted by the collimator. In the case of rotation of chopper wheel 61 about effective center 36, the centroid of focal spot 18 lies, more particularly, along the line defined by effective center 36 and the central bore of collimator jaw 30. Thus, the centroid of focal spot 18 is scanned in an arc in synchrony with the change in direction of the beam 64 of penetrating radiation. As a result of the operation as described, the distribution of emitted x-rays 20 is always similarly located with respect to collimator jaw 30 and distortion of the beam as viewed along beam direction 64 will thereby be advantageously minimized. The size of the collimator wheel is determined by the required image resolution and the size of the x-ray tube focal spot. By reducing the focal spot size, the collimator wheel may be made smaller (without degrading the image resolution). By raster scanning the focal spot in one dimension across the target, as described above, the size of the focal spot can be reduced, while maintaining a constant average energy density on the target. Thus, a reduction in the size of the collimator wheel is facilitated. By aligning the direction of the one-dimensional raster scan with the direction of the x-ray beam sweep, adverse affects on the image quality due to the raster scanning of the focal spot are advantageously reduced. In accordance with embodiments of the present invention, the dimensions of the focal spot 18 incident on target 16 may be asymmetrical with respect to its dimensions in the directions parallel and perpendicular to the direction of scanning of the beam. Thus, as shown in FIG. 4, width w of focal spot 18 in direction 40 corresponding to the direction of extraction of x-rays from target 16 is smaller, typically by a factor of approximately 5, from that typically employed for a fixed focal spot. The height h of focal spot 18 is comparable to that employed for a fixed focal spot arrangement. Electron beam 12 is swept across target 16 in direction 42, such as by applying a periodic input voltage, such as a sinusoidal voltage, for example, to deflection coils 24 (shown in FIG. 2). Thus, while the focal spot is smaller, the time averaged power per unit area on the target is advantageously reduced and local overheating of the target may be prevented. By applying the teachings provided in the above discussion, a uranium wheel of a diameter smaller by a factor of four from a diameter typical for a particular application may be employed. It is to be understood that embodiments other than rotation of the spokes of a chopping wheel may be used in accordance with the invention for creating a scanning beam of x-rays. Thus, for example, a slit may be translated relative to the source of penetrating radiation in order to form a scanning fan beam. In this case, in accordance with an alternate embodiment of the invention, a focal region of incidence of the particle beam on the target, having a substantially rectangular shape, may be scanned across the target subject to a constraint analogous to that described above: namely, the focal region lies in a plane instantaneously containing the emitted fan beam, possibly relative to an effective vertex of motion of the scanning beam. In accordance with an alternate embodiment of the concept heretofore described, a translated linear slit 48 is described with reference to FIG. 5. An electron beam (designated by numeral 12 in FIG. 2) is incident, from a direction directed substantially out from behind the plane of the page, onto an arcuate target or anode 16. A tungsten cylinder 50 rotates about an axis 52 perpendicular to the plane of the page thereby scanning slit 48 in synchrony with the motion of focal spot 18 on the face of anode 16. Axis 52 coincides with the center of curvature of anode 16 such that the emitted x-ray beam always passes through the center of curvature 52. Shielding 54, typically lead, is provided so that x-ray radiation is emitted only via slit 48. Cylinder 50 has a transverse collimating hole 56 defining the size of the emitted beam of penetrating radiation. With a single slit 48 as shown, an x-ray beam is emitted approximately 40% of the time. If two perpendicular slits are used, the beams exit 80% of the time. The 20% dead time may be used for flyback of the electron beam to begin the scanning cycle of focal spot 18 on target 16. Advantages of the rotating slip embodiment of FIG. 5 include the smaller size of the rotating element and the flexibility afforded in the placement of the x-ray anode and its shielding and cooling. Additionally, the x-ray beam may advantageously be taken off in the forward direction with respect to the electron beam, with an attendant gain in the power and energy of the x-ray spectrum, especially at high electron energies. Additionally, the linear scan length (in the dimension into the page) may be extended relative to the limited axial opening of a chopper wheel configuration. Referring now to FIG. 6, a pair of counter-rotating slits 48 and 58 are shown in cross-section, for generating a high duty cycle scanning x-ray beam in accordance with an alternate embodiment of the present invention. A first cylinder 50 rotates in a clockwise sense, in synchrony with the scanning of a focal spot of the electron beam onto a target during a portion of a cycle, whereas a second cylinder 60 counterrotates with respect to first cylinder 50, but is in synchrony with the scanning focal spot of the electron beam onto the target during a second portion of the cycle. The electron beam oscillates along two closely parallel arcs on the anode, thus, the electron beam moves up along a first arc, generating s-rays that pass through first cylinder 50, then jogs and moves down a second arc, generating s-rays that pass through the collimator of the abutting second cylinder 60. In accordance with a further embodiment of the invention, the integrity of the x-ray beam exiting from the collimator may be enhanced by providing a signal based on the angular position of the collimating cylinder to control the steering coil that governs the direction of the electron beam in the x-ray generator. The described embodiments of the invention are intended to be merely exemplary and numerous variations and modifications will be apparent to those skilled in the art. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.
	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 High Energy Beam Diffraction Material Treatment System and currently pending, 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 now 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. 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. 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. 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).